Radiometric Dating - A.Snelling

Dr. Andrew A. Snelling Education PhD, Geology, University of Sydney, Sydney, Australia, 1982 BSc, Applied Geology, The University of New South Wales, Sydney, Australia, First Class Honours, 1975 Professional Experience 

Field, mine, and research geologist, various mining companies, Australia

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, Australian Nuclear Science and Technology Organisation (ANSTO), Consultant researcher and writer , Australia, 1983–1992

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Geological consultant, Koongarra uranium project, Denison Australia PL, 1983–1992

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Collaborative researcher and writer, Commonwealth Scientific and Industrial Organisation (CSIRO), Australia, 1981–1987

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Professor of geology, Institute for Creation Research, San Diego, CA, 1998–2007

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Staff member, Creation Science Foundation (later Answers in Genesis–Australia), Australia, 1983– 1998

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Founding editor, Creation Ex Nihilo Technical Journal (now Journal of Creation), 1984–1998

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Researcher and editor, Radioisotopes and the Age of The Earth (RATE), 1997–2005

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Editor-in-chief, Proceedings of the Sixth International Conference on Creationism, 2008

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Director of Research, Answers in Genesis, Petersburg, KY, 2007–present

Professional Affiliations Geological Society of Australia /Geological Society of America /Geological Association of Canada/ Mineralogical Society of America /Society of Economic Geologists /Society for Geology Applied to Mineral Deposits / Creation Research Society /Creation Geology Society Dr. Andrew A. Snelling is perhaps one of the world's leading researchers in flood geology.He worked for a number of years in the mining industry throughout Australia undertaking mineral exploration surveys and field research. He has also been a consultant research geologist for more than a decade to the Australian Nuclear Science and Technology Organization and the US Nuclear Regulatory Commission for internationally funded research on the geology and geochemistry of uranium ore deposits as analogues of nuclear waste disposal sites..His primary research interests include radioisotopic methods for the dating of rocks, formation of igneous and metamorphic rocks, and ore deposits. He is one of a controlled number permitted to take rock samples from the Grand Canyon.He was also a founding member of the RATE group (Radioisotopes and the Age of The Earth). Andrew completed a Bachelor of Science degree in Applied Geology with First Class Honours at The University of New South Wales in Sydney, and graduated a Doctor of Philosophy (in geology) at The University of Sydney, for his thesis entitled A geochemical study of the Koongarra uranium deposit, Northern Territory, Australia. Between studies and since, Andrew worked for six years in the exploration and mining industries in Tasmania, New South Wales, Victoria, Western Australia and the Northern Territory variously as a field, mine and research geologist. Full-time with the Australian creation ministry from 1983 to 1998, he was during this time also called upon as a geological consultant to the Koongarra uranium project (1983–1992). Consequently, he was involved in research projects with various CSIRO (Commonwealth Scientific and Industrial Research Organisation), ANSTO (Australian Nuclear Science and Technology Organisation) and University scientists across Australia, and with scientists from the USA, Britain, Japan, Sweden and the International Atomic Energy Agency. As a result of this research, Andrew was involved in writing scientific papers that were published in international scientific journals.Andrew has been involved in extensive creationist research in Australia and overseas, including the formation of all types of mineral deposits, radioactivity in rocks and radioisotopic dating, and the formation of metamorphic and igneous rocks, sedimentary strata and landscape features (e.g. Grand Canyon, USA, and Ayers Rock, Australia) within the creation framework for earth history. As well as writing regularly and extensively in international creationist publications, Andrew has travelled around Australia and widely overseas (USA, UK, New Zealand, South Africa, Korea, Indonesia, Hong Kong, China) speaking in schools, churches, colleges and universities, particularly on the overwhelming scientific evidence consistent with the Global Flood and the Creation.

THE RADIOMETRIC DATING          

Radioisotopes and the Age of the Earth ………………………………………………………………………………4 Radiometric Dating: Back to Basics ……………………………………………………………………………………9 Radiometric Dating: Problems with the Assumptions ………………………………………………………………..11 Radiometric Dating: Making Sense of the Patterns ………………………………………………………………….13 Radioactive “Dating” Failure Recent New Zealand Lava Flows Yield “Ages” of Millions of Years ……….……..14 Radioactive Dating Method ‘Under Fire’ ………………………………………………………………………………16 RATE Radioisotopes and the Age of the Earth ……………………………………………………………………….19 U-Th-Pb “Dating”: An Example of False “Isochrons” …………………………………………………………………20 The Failure of U-Th-Pb ‘Dating’ at Koongarra, Australia …………………………………………………………….25 Determination of the Radioisotope Decay Constants and Half-Lives: Rubidium-87 (87Rb) ………………….….43 ***

CARBON DATING        

Carbon-14 Dating Understanding the Basics ……………………………………………………………………50 Carbon-14 in Fossils and Diamonds An Evolution Dilemma …………………………………………….……..51 A Creationist Puzzle 50,000-Year-Old-Fossils …………………………………………………………………..53 Measurable 14C in Fossilized Organic Materials: Confirming the Young Earth Creation-Flood Model ……54 Radiocarbon Ages for Fossil Ammonites and Wood in Cretaceous Strata near Redding, California ……..63 Radiocarbon in Diamonds Confirmed ………………………………………………………………………….….71 Geological Conflict Young Radiocarbon Date for Ancient Fossil Wood Challenges Fossil Dating……….…72 Radiocarbon in an ‘ancient’ fossil tree stump casts doubt on traditional rock/fossil dating …………..….….75

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Determination of the Radioisotope Decay Constants and Half-Lives: Lutetium-176 (176Lu)……………….76

*** Determination of the Radioisotope Decay Constants and Half-Lives: Rhenium-187 (187Re)………………85 Determination of the Radioisotope Decay Constants and Half-Lives: Samarium-147 (147Sm)…………….95

DATING RESULTS            

Significance of Highly Discordant Radioisotope Dates for Precambrian Amphibolites in Grand Canyon, USA ………..105 Whole-Rock K-Ar Model and Isochron, and Rb-Sr, Sm-Nd, and Pb-Pb Isochron, “Dating” of the Somerset Dam Layered Mafic Intrusion, Australia ………..117 Radioisotopes in the Diabase Sill (Upper Precambrian) at Bass Rapids, Grand Canyon, Arizona An Application and Test of the Isochron Dating Method ……….130 Discordant Potassium-Argon Model and Isochron “Ages” for Cardenas Basalt (Middle Proterozoic) and Associated Diabase of Eastern Grand Canyon, Arizona ………..140 The Relevance of Rb-Sr, Sm-Nd, and Pb-Pb Isotope Systematics to Elucidation of the Genesis and History of Recent Andesite Flows at Mt. Ngauruhoe, New Zealand, and the Implications for Radioisotopic Da ……….150 The Cause of Anomalous Potassium-Argon “Ages” for Recent Andesite Flows at Mt. Ngauruhoe, New Zealand, and the Implications for Potassium-Argon “Dating” ……….161 The Fallacies of Radioactive Dating of Rocks Basalt Lava Flows in Grand Canyon …………………….…172 Radioisotope Dating of Rocks in the Grand Canyon ……………………………………………………………174 Radioisotope Dating of Rocks in the Grand Canyon ……………………………………………………………175 Radioactive “Dating” in Conflict! Fossil Wood in “Ancient” Lava Flow Yields Radiocarbon …………………178 The age of Australian Uranium A case study of the Koongarra uranium deposit …………………….………179 Helium Diffusion Rates Support Accelerated Nuclear Decay …………………………………………………..183

METEORS

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Radioisotope Dating of Meteorites: I ………………………………………………………………………………195 Radioisotope Dating of Meteorites: II ……………………………………………………………………………..239 Radioisotope Dating of Meteorites: III ……………………………………………………………………………..277

Radioisotopes and the Age of the Earth by Dr. Russell Humphreys, Dr. Steve Austin, Dr. Don DeYoung, Eugene Chaffin, Dr. Andrew A. Snelling, and Dr. John Baumgardneron March 9, 2011 Abstract RATE is an acronym applied to a research project investigating radioisotope dating sponsored by the Institute for Creation Research and the Creation Research Society. It stands for Radioisotopes and the Age of The Earth. This article summarizes the purpose, history, and intermediate findings of the RATE project five years into an eightyear effort. It reports on the latest status of the research on helium diffusion through minerals in granitic rock, accelerated nuclear decay theory, radiohalos, isochron discordance studies, case studies in rock dating, and carbon-14 in deep geologic strata. Each of the RATE scientists will present separate technical papers at the Fifth International Conference on Creationism on the details of this research. Keywords: radioisotopes, isotopes, age, dating, nuclear decay, accelerated nuclear decay This paper was originally published in the Proceedings of the Fifth International Conference on Creationism, pp. 337–348 (2003) and is reproduced here with the permission of the Creation Science Fellowship of Pittsburgh (www.csfpittsburgh. org). Introduction The conventional scientific view typically expressed today is that the earth is about 4.6 billion years old and the universe between 10 and 20 billion years old. These estimates are based primarily on the abundances of parent and daughter radioisotopes and the implications of stellar and cosmological models. Yet, a literal interpretation of Scripture and much scientific evidence has been gathered to indicate that the creation of the earth, the solar system, and the universe occurred only a few thousand years ago.One of the principal forces which has traditionally driven estimates of an old age for the earth is the necessity for long periods of time for evolution. Even before radioactivity was discovered in the 1890s, estimates of the age of the earth were growing longer and longer as the complex nature of life became more evident. However, it has never been demonstrated that the evolution of life from inorganic chemicals has occurred or that life has evolved from simple life forms to the complex ones we see today. Living systems, even the simplest ones, are based upon symbolic language structures of extreme complexity. There is no hint in the laws of chemistry and physics that matter on its own can ever generate symbolic language regardless of the time allowed. Because it has no solution to this fundamental difficulty, evolutionary dogma is now facing a major crisis that long periods of time simply cannot mend.Young-earth creationists on the other hand are not convinced that long periods of time have transpired since the origin of the earth—and some include the origin of the entire universe. In defending a young-earth position, they typically point to important assumptions underlying these dating schemes. For example, when a parent isotope decays into a daughter isotope, the initial concentration of the daughter isotope may affect the estimate of time since the process started. Creationists in some cases question the conventional assumption that the initial amount of daughter product is small or at least can be tightly constrained. Isochron methods attempt to remove this uncertainty, but the results are not wholly satisfactory. Also often questioned by creationists are the assumptions that the quantities of the parent and daughter isotopes have not been altered by non-radioactive processes such as migration and transport, and that the rate of decay from parent to daughter has been constant during the period under consideration. Most researchers attempt to justify each of these three assumptions, but ultimately no one can be certain if the conditions have been met, particularly over long periods of time. It is hypothesized by the RATE group that at some time in the past much higher rates of radioisotope decay have occurred, leading to the production of large quantities of daughter products in a short period of time. It has been suggested that these increased decay rates may have been associated with the rock-forming processes on the early earth.The RATE group suspects that large amounts of radioactive decay may have occurred during the first two and a half days of creation as part of the supernatural creation process. The jury is still out and, until we complete our research phase, this thesis remains tentative. The presence of supernatural “process” during creation is essential to our approach, however. Scripture talks of at least two major events which occurred after creation, the Judgment in the Garden of Eden and the Flood. It would seem appropriate to consider at least that an original distribution of elements could have been mixed, and radioactive processes speeded up during one or both of these events. History of the RATE Project On July 5, 1997 a group of young-earth creationist researchers met in San Diego, California to address the issue of reconciling radioisotopes and the age of the earth as reported by Vardiman.1 It was recognized by the group that this was a significant problem which must be addressed if young-earth creationism was to continue to have a significant impact on the issue of origins both within and outside the creation community. The group, which has since become known as RATE, decided that the primary approach would be to explore accelerated rates of decay of radioisotopes during one or more of the Creation, Fall, and Flood events. A second approach would be to address the mixing of mantle and crustal reservoirs since the origin of the earth. Additional processes and issues have been suggested and explored as part of the research. The focus of the RATE research would be primarily on long-age isotopes and their use as chronometers.By February, 2003 six annual meetings of RATE had been held by the principal investigators. These meetings included reports, discussion, allocation of funds, and research decisions. During the third meeting thirteen research experiments were identified as shown in Tables 1 and 2. A brief description of each experiment, expected results, the estimated cost, and estimated time were developed. At the annual meeting in 2001 the importance to this project of 14C in deeply buried fossil material was identified, and a research thrust on this topic was added. The cost of the eight-year project was estimated to be about $500,000. Before 2002 about 80% of these funds had been raised through private donations. Two major reports were planned for RATE. The first report, a 675-page book was published in December 2000 entitled, Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Initiative. It contains an introduction to the project, a report on the literature searches by the principal investigators on most of the topics of concern, a glossary, and a set of research proposals. The purpose of the initial report was to stake a claim. It was also published to lend structure and direction to the effort and to inform contributors about what they could expect from their donations. The second and final book is planned to be published in 2005 and is

expected to be titled Radioisotopes and the Age of the Earth: A Young-Earth Creationist Research Report. It will report on the findings of the five-year research phase. Intermediate Results of RATE Research Helium Diffusion—Dr. D. Russell Humphreys, PI Two decades ago, it was reported by Gentry, Glish, and McBay2 that up to 58% of the helium (a daughter product of uranium and thorium decay) generated during the alleged 1.5 billion year age of the Precambrian granodiorite beneath the Jemez Mountains near Los Alamos, New Mexico, was still in the zircons embedded in the biotite crystals contained within the granodiorite. Yet, the zircons were so small (see Fig. 1 for a picture of typical zircons) that they should not have retained the helium for even a small fraction of that time. The high retentions suggest to us and many other creationists that the helium has not had time to diffuse out of the zircons—that accelerated nuclear decay produced over a billion years worth of helium only thousands of years ago. Such accelerated decay could reduce the radiometric timescale from gigayears down to months.A theoretical creationist model, based on observed helium retention, of diffusion rates of helium over a period of 6,000 years was reported by Humphreys3 and Humphreys et al.4). It compares well with laboratory measurements in Jemez zircons, as shown in Fig. 2. The solid dots show the diffusion coefficient as a function of inverse temperature for the measurements with the Jemez zircons and the solid lines through empty squares show the theoretical predictions from the theoretical model. There is a five-order-of-magnitude difference (100,000 ×) between the predictions of diffusion for the evolutionist and creationist models. The measured diffusion rates of He predict that helium would leak out of a zircon/biotite matrix in a period of time on the order of thousands of years, not hundreds of millions of years. This is consistent with the high concentrations of helium still found in the Jemez granodiorite. Table 1. High priority RATE experiments. Experiment

Description

Expected Results

Time

He Diffusion

Acquisition of data on which to base a claim that the amount of He in rocks today should not be so high if it was produced by nuclear decay over millions of years. If the He Determine He diffusion rates throughwas produced within the most recent thousands of years, it minerals under various conditions would be expected to remain still in the rocks as observed. 2 years

Isochron Discordance

Increased evidence for discordance among isotopic dating methods using isochrons for mineral components of FloodConstruct 5-point mineral and whole-rockrelated rocks. Based on the consistency of the discordance isochrons on selected basaltic rocksfrom these specimens and others, infer the processes formed during the Flood which led to the distribution of isotopes. 2 years

Conduct a literature search for evidence and models of accelerated nuclear decayIncrease evidence that nuclear decay can vary radically in and adapt to a creationist worldview, if response to changes in cosmological “constants” and Nuclear appropriate. Complete studies on a and benvironmental effects. Associate other likely effects with Decay Theory decay. biblical statements and observational data. 2 years

Radiohalos

Determine the geological distribution of Resolve the question if Po halos are special evidence for Po halos, their proximity tocreated rocks only , or could they also occur in Flood rocks. concentrations of U and the relationshipThis effort may also allow inferences about the process of to different halo types. radioisotope decay and halo formation. 5 years

Fission Tracks

Estimate nuclear decay rates during theFission track estimates of nuclear decay rates are thought Flood using the fission track method.to be absolute following rock formation and do not inherit Select an initial sample from a tuff bed in prior evidence of decay. It is important to know if decay the Muav Formation of Grand Canyon. rates were accelerated during the Flood. 2 years

Additional laboratory measurements and modeling studies of helium diffusion in zircon are expected to lead to a further refinement of the creationist model. The data of Fig. 2 indicate an age between 4,000 and 14,000 years since the helium began to diffuse from the zircons. This is far short of the 1.5 billion year evolutionist age! We believe that the final results will resoundingly support our hypothesis concerning diffusion and radiogenic helium. Table 2. Lower priority RATE experiments. Experiment Uranium Halos

Time (years) (U)/Thorium

(Th) 4

Case Studies in Rock Dating

5

Biblical Word Studies

2

Pu in OKLO Reactor

1

Allende Meteorite Origin

1

Diffusion of Ar in Biotite

2

Origin of Chemical Elements

2

Cosmology and Nuclear Decay

5

Search for Carbon-14 *

3

* Added in 2001 Nuclear Decay Theory—Dr. Eugene F. Chaffin, PI

Fig. 1. Zircons from the Muav Tuff, Grand Canyon, Arizona (Courtesy of Geotrack International Laboratory).

The quantum theory of alpha and beta decay are being reviewed by Chaffin,5,6 with extensions of the standard models being explored to see if they could lead to accelerated decay during episodic variations of the coupling constants. Variations in the radii of compactified extra dimensions and consequent variation in coupling constants over the history of the universe could cause accelerated decay. If, during early Creation Week, say the first 2+ days before the creation of plants, such variations were to occur, they could lead to accelerated nuclear decay, thus adjusting isotopic abundances, without giving unacceptable doses of radiation to life.Grasses, herbs, and fruit

trees which could have been damaged by high radiation. Fig. 2. Plot of diffusion coefficient of He in zircon vs. inverse temperature. Fig. 3. Plot of nuclear potential energy vs. radial distance from the center of a nucleus. These variations may help explain the abundances of radioisotopes, including radioactive equilibrium found in decay chains such as the uranium series, within the young-earth time frame. We are also exploring the tunneling theory of alpha decay to see how much change in half-life is possible without drastically affecting other measurable properties of nuclei. For only slight changes in the depth of the nuclear potential well (see Fig. 3), abrupt changes in the number of nodes of the alpha particle wave function occur which can lead to drastic changes in half-life. Also, the half-life depends exponentially on the shape of the potential well, so that even slight changes are effective in accelerating alpha-decay. PIThe significance of radiohalos is due to the fact they represent a physical, integral historical record of the decay of radioisotopes in the radiocenters over a period of time as discussed by Snelling7 and Snelling and Armitage.8 The darkening of the minerals surrounding the radiocenters is caused by damage to their crystal structure by alpha particles produced by nuclear decay. As part of a systematic effort to investigate radiohalo occurrences in granitic rocks globally and throughout the geologic record, suitable samples have been collected from the La Posta (southern California), Stone Mountain (near Atlanta, Georgia) and Cooma (southern New South Wales, Australia) plutons. Fig. 4. Number of radiohalos vs. type and location. The biotite crystals in all these granites contain abundant 238U, 210Po, and 214Po radiohalos. The occurrence ratio is approximately five 210Po radiohalos for every 214Po and 238U radiohalo, which occur roughly in equal numbers except in the Cooma pluton (see Fig. 4). While these radiohalos are homogeneously distributed throughout the mineralogically uniform Stone Mountain pluton, they are almost exclusively concentrated in the muscovite-biotite granodiorite core of the La Posta pluton. Furthermore, there are four to five times more of all these radiohalos in the associated late-stage, Indian Hills granite (southern California).Hydrothermal fluids are invariably concentrated in the last liquid phases during the rapid convective cooling of granite plutons as discussed by Snelling and Woodmorappe,9 so this pattern of radiohalo occurrence in the La Posta pluton and Indian Hills granite strongly suggests that the Po radiohalos have formed as a result of late hydrothermal fluid transport of Po radioisotopes locally within the biotite flakes separating them from their parent 238U in the zircons.The Cooma granite was produced by partial melting at the center of a regional metamorphic complex. Thus, this research has the potential to demonstrate that both the cooling of granite plutons and regional metamorphism occurred within weeks to months, not over millions of years, because of the short half-life of 218Po. Radiohalo occurrences in other granitic plutons at many levels in the geologic record are also under continuing investigation. Isochron Discordance—Dr. Steven A. Austin, PI Field observations, petrographic study, and geochemical analysis by Snelling, Austin, and Hoesch10 indicate that a 95-meter-thick sill in sharp contact with the intruded Hakatai shale near Bass Rapids in Grand Canyon was well mixed isotopically when emplaced. However, after

intrusion, it segregated mineralogically and chemically by crystal settling. Such a condition of thorough isotopic mixing followed by rapid chemical segregation is ideally suited to test the assumptions that underlie whole-rock and mineral isochron dating. Both creationists and evolutionists should accept the well-mixed initial isotopic condition of the original magma body. Fig. 5. Isochron age vs. half-life and mode of decay. New K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb radioisotope data from eleven whole-rock samples (eight diabase, three granophyre) and six mineral phases separated from one of the whole-rock diabase samples yield discordant whole-rock and mineral isochron “ages.” These isochron “ages” range from 842 ± 164 Ma (whole-rock K-Ar) to 1375 ± 170 Ma (mineral Sm-Nd). (See Fig. 5 for a graph of the isochron “age” versus half-life and type of decay for each of the four radioisotope systems investigated.) Although significant discordance exists between the K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb radioisotope methods, each method appears to yield concordant “ages” internally between whole rocks and minerals. Internal concordance is best illustrated by the Rb-Sr whole-rock and mineral isochron “ages” of 1055 ± 46 Ma and 1059 ± 48 Ma, respectively. It is, therefore, argued that only changing radioisotope decay rates in the past could account for these discordant isochron “ages” for the same geologic event. Furthermore, these data are consistent with alpha decay having been accelerated more than beta decay, and with a greater acceleration factor for a greater present half-life. Case Studies in Rock Dating—Dr. Andrew A. Snelling, PI Snelling11,12 earlier reported having obtained K-Ar model ages for recent andesites collected from Mt. Ngauruhoe in New Zealand. Dates of less than 0.27 to 3.5 Ma could not be reproduced, even from splits of the same samples from the same flow, the explanation being variations in the 40Ar* (radiogenic 40Ar) content in excess of the “zero-age” amount. It was concluded that this excess 40Ar* had been inherited by these magmas during their genesis in the upper mantle. Two samples from each of the lava flows and deposits have now been analyzed for Rb-Sr, Sm-Nd, and Pb-Pb isotopes. Together with the trace and rare earth element analyses, they further elucidate the petrogenetic history of these andesites, including crustal components which may have contaminated originally pure basalt magmas. Whereas valid isochron ages cannot be obtained from this isotopic data except by subjective manipulation, depleted mantle Nd model ages of 801–1594  Ma and positive εNd(to) values suggest the original basalt magmas were generated from partial melting of the residual solids in old depleted upper mantle, while the large positive εSr(to) values and the 87Sr/86Sr ratios suggest contamination during their ascent with basement greywackes to produce the andesite magmas. Consequently, evidence continues to accumulate that systematic mixing of mantle and crustal sources makes it nearly impossible to obtain unambiguous radioisotopic results in these environments.

Fig. 6. Petrogenetic model of melt formation near a subducting slab, based on Tatsumi17 and Davies and Stevenson.18 Mixing and inheritance of radioisotopes invalidate conventional age dating. The petrogenetic model therefore favored by Gamble et al.,13 which is consistent with all the isotopic data discussed in Snelling,14 and shown in Fig. 6, is based on Tatsumi15 and Davies and Stevenson.16 This model envisages a zone of melt formation approximately coincident to the volcanic front, which includes Ruapehu and Ngauruhoe, and a melt generation region delimited by the interface of the subducting slab, the base of the arc lithosphere (of continental New Zealand) and two vertical columns, one delineating the volcanic front, the other, the coupled back-arc basin. Fluids liberated from the descending slab ascend into and enrich the overlying periodite down to higher pressures, where the amphibole breaks down giving rise to amphibole dehydration, while progressive dehydration reactions in the slab itself lead to fluid transfer from the slab into the mantle wedge, both processes producing partial melting as amphibole breaks down over the depth range 112 ±  19 km as discussed by Tatsumi19 and Davies and Stevenson.20 The lower density melt then rises and pools in the upwelling melt column, eventually penetrating upwards into the overlying arc lithosphere to fill magma chambers that then

erupt when full.The Rb-Sr, Sm-Nd, and Pb-Pb radioisotopic ratios in the samples of this study of recent (1949–1975) andesite lava flows at Mt. Ngauruhoe, New Zealand, as anticipated, do not yield any meaningful age information, even by selective manipulation of the data. Instead, these data provide evidence of the mantle source, of magma genesis, and of the crustal contamination of the parental basalt magmas. By implication, the radioisotopic ratios in ancient lavas found throughout the geologic record must similarly express the fundamental characteristics of their geochemistry. They therefore must also strongly reflect the magmatic origin of the lavas from mantle and crustal sources and any history of mixing or contamination in their petrogenesis which can dramatically distort any inferred isotopic age. Even though radioisotopic decay has undoubtedly occurred during the earth’s history, conventional radioisotopic dating of these rocks therefore cannot provide valid absolute ages for them. This is especially so if accelerated nuclear decay accompanied the catastrophic geologic and tectonic processes responsible for the mixing of the radioisotopic decay products during magma genesis. Fifteen rock samples have also been collected from the Somerset Dam gabbro intrusion near Brisbane, Australia (Snelling21), probably a well-preserved, unmetamorphosed subvolcanic magma chamber. The samples were processed and submitted to various laboratories for whole-rock major and trace element analyses and for K-Ar, Rb-Sr, Sm-Nd, and PbPb radioisotopic analyses. Additionally, one of the gabbro samples from one of the cyclic units was separated into its mineral constituents using heavy liquids, and the resultant plagioclase, augite, olivine, and magnetite-ilmenite concentrates, along with a duplicate piece of the whole-rock, submitted for K-Ar, Rb-Sr, Sm-Nd, and Pb-Pb radioisotopic analyses. The objective of this study was not only to compare the different dating methods, but also to compare whole-rock and mineral isochron ages and to test whether there are variations in the radioisotopes between the cyclic units, and between the macrolayers within them. From these studies it may be possible to infer how mixing occurs in a magma chamber and demonstrate that radioisotopic compositions of crustal rock may reflect characteristics of the magma sources in the mantle rather than the ages of the intrusion. Significant Amounts of 14C in Deep Strata—Dr. John R. Baumgardner, PI Fig. 7. Distribution of 14C values for biogenic samples from the radiocarbon literature. Given their position in the geological record, all these samples should contain no detectable 14C according to the conventional geological timescale. Fig. 8. Histogram representation of AMS14C analysis of ten coal samples undertaken by the RATE 14C research project. According to the conventional geologic time-scale, organic materials older than about 250,000 years should be utterly 14C “dead.” This is because the half-life of 14C, only 5,730 years, is so short. 250,000 years of decay (corresponding to 43.6 half-lives) reduces the number of initial14C atoms by a factor of 7 × 10-14. A gram of modern carbon contains about 6  × 1010 14C atoms, so not a single 14C atom should remain after 250,000 years. The astonishing result, however, is that, almost without exception, when tested by accelerator mass spectrometer (AMS) methods, organic samples from every portion of the Phanerozoic record show detectable and reproducible amounts of 14C! This reality has been established as dozens of AMS laboratories around the world over the last 20 years have sought desperately to understand why organic samples from deep within the geological record, thought to be tens to hundreds of millions of years old, should consistently contain 0.1–0.5% of the modern level of 14C. Believing this 14C had to be contamination, they have mounted an intense quest to identify and eliminate sources of contamination in their AMS procedures. But despite improvements in techniques, this level of 14C, on the order of 0.1–0.5 percent modern carbon (pmc), continues to be reported for samples that, given their location in the geological record, should be entirely 14C “dead.” Many scores of such measurements are readily available in the standard peer-reviewed radiocarbon literature as documented by Giem22 and Baumgardner et al.23 and displayed in Fig. 7. Measurable 14C at roughly uniform values in pre-Flood organic materials fossilized in Flood strata, of course, represents powerful support for the young earth Creation-Flood model.Aware of this, Snelling24,25,26,27,28 analyzed the 14C content of fossilized wood conventionally regarded as 14C “dead” because it was derived from Tertiary, Mesozoic, and upper Paleozoic strata having conventional ages of 40 to 250 million years. All samples were analyzed using AMS technology by a reputable commercial laboratory, with some duplicate samples also tested by a specialist laboratory in a major research institute. Measurable 14C well above background was obtained in all cases.More recently, as a check on the AMS results in the peer-reviewed literature, the RATE team acquired a suite of ten coal samples from the U.S. Department of Energy Coal Repository. These samples represent important U.S. coal deposits and span the geological record from Carboniferous to Eocene. The 14C measurements by one of the best AMS laboratories in the world for these ten samples are displayed in graphical form in Fig. 8 and discussed in Baumgardner et al.29 The 14C levels for these samples fall nicely within the range of values shown in Fig. 7. We conclude that the well-documented evidence of 14C in fossil organic material provides compelling support for the young earth Creation-Flood model and represents a severe challenge for the uniformitarian assumptions underlying the long half-life radioisotope methods. Tentative Conclusions

At this point in the RATE research several tentative conclusions are beginning to emerge, based on the literature searches, theoretical studies, and laboratory findings. Although some are firmer than others, the following conclusions are likely to be in the final report. There will likely also be additional conclusions which are too early to include at this time. The tentative conclusions will only be reported here in outline form. More detail and justifications for most of these conclusions are discussed in the referenced papers in these Proceedings. Conventional radioisotope dating methods are unreliable. Discordance among different dating methods is common. Key assumptions underlying radioisotope dating methods are untenable. Mixing of mantle and crustal sources also mixes their isotopic signatures. Residual 14C appears to be present in all fossil biogenic material. Massive nuclear decay has occurred in rocks. Large quantities of daughter elements like Pb, He, and Ar are present. Many of the daughter elements are in proximity to the parent elements. Fission tracks and radiohalos are numerous. Isotopic mixing between the earth’s mantle and crust has occurred. Lava flows exhibit isotopic characteristics of the mantle. Isotopic data suggest basalts were generated from melting of old mantle. Isotopic data also suggest basalt magmas were contaminated during their ascent. Residual He and radiohalos suggest recent nuclear decay. Large quantities of He are still present in many granites today. If He was formed millions of years ago, it should have already escaped. Experimentally-determined diffusion rates of He agree with recent production of He. Po halos appear to have formed during rapid cooling of granite plutons during the Flood (eliminating millions of years). If the cooling of the plutons was rapid, then metamorphism was also rapid during the Flood (eliminating millions of years). Massive nuclear decay, radiohalos, helium diffusion, and deep 14C all imply accelerated decay. Massive nuclear decay requires higher decay rates before the present. Radiohalos formed during the Flood require decay rates higher than observed today. Helium diffusion data imply the decay occurred within thousands of years ago. Deep 14C implies the decay occurred within thousands of years ago. Studies in theoretical physics suggest accelerated nuclear decay can occur. Variation in compactified dimensions could affect coupling constants. Consequent variation in coupling constants could cause accelerated decay. Changes in potential well depth change the α-particle wave function. Changes in the α-particle wave function change decay half-lives. Summary The basic conclusion of this research is that conventional radioisotopic dating methods are unreliable. The chief reason is that uniformitarianism is not a legitimate model of earth history. Observational evidence supports the recent occurrence of a global catastrophic Flood. Because the earth has suffered a major tectonic catastrophe corresponding to the Flood, the uniformitarian assumptions that are applied to obtain age estimates from radioisotopic data are simply not true. Intermediate results from RATE support a young-earth, catastrophic, creationist model.Two remaining years in the research phase will be needed to complete the analysis of samples yet being processed and theoretical studies still being made. By the end of the research phase the final report should be based on a larger data set than was available for this paper. A few research projects within RATE such as Fission Tracks and Biblical Word Studies that have not been discussed in this paper are also expected to contribute to the final report. It is apparent that significant progress has been made in explaining the presence of large quantities of nuclear decay products in a young-earth time frame. The evidence should be stronger and more convincing by the time the research project is completed in 2005. We also hope that by then a more detailed young-earth creationist model of the history of radioactive decay will also have been developed. Radiometric Dating: Back to Basics by Dr. Andrew A. Snelling on June 17, 2009; last featured February 19, 2014 Radiometric dating is often used to “prove” rocks are millions of years old. Once you understand the basic science, however, you can see how wrong assumptions lead to incorrect dates. Shop Now Radiometric Dating 101 PART 1: Back to Basics PART 2: Problems with the Assumptions PART 3: Making Sense of the Patterns This three-part series will help you properly understand radiometric dating, the assumptions that lead to inaccurate dates, and the clues about what really happened in the past. Most people think that radioactive dating has proven the earth is billions of years old. After all, textbooks, media, and museums glibly present ages of millions of years as fact. Yet few people know how radiometric dating works or bother to ask what assumptions drive the conclusions. So let’s take a closer look and see how reliable this dating method really is. Atoms—Basics We Observe Today Each chemical element, such as carbon and oxygen, consists of atoms. Each atom is thought to be made up of three basic parts.The nucleus contains protons (tiny particles each with a single positive electric charge) and neutrons (particles without any electric charge). Orbiting around the nucleus are electrons (tiny particles each with a single negative electric charge).

The atoms of each element may vary slightly in the numbers of neutrons within their nuclei. These variations are called isotopes of that element. While the number of neutrons varies, every atom of any element always has the same number of protons and electrons.So, for example, every carbon atom contains six protons and six electrons, but the number of neutrons in each nucleus can be six, seven, or even eight. Therefore, carbon has three isotopes (variations), which are specified carbon-12, carbon-13, and carbon-14 (Figure 1). Radioactive Decay Some isotopes are radioactive; that is, they are unstable because their nuclei are too large. To achieve stability, the atom must make adjustments, particularly in its nucleus. In some cases, the isotopes eject particles, primarily neutrons and protons. (These are the moving particles measured by Geiger counters and the like.) The end result is a stable atom, but of a different chemical element (not carbon) because the atom now has a different number of protons and electrons.This process of changing one element (designated as the parent isotope) into another element (referred to as the daughter isotope) is called radioactive decay. The parent isotopes that decay are called radioisotopes.Actually, it isn’t really a decay process in the normal sense of the word, like the decay of fruit. The daughter atoms are not lesser in quality than the parent atoms from which they were produced. Both are complete atoms in every sense of the word.Geologists regularly use five parent isotopes to date rocks: uranium-238, uranium-235, potassium-40, rubidium-87, and samarium-147. These parent radioisotopes change into daughter lead-206, lead-207, argon-40, strontium-87, and neodymium-143 isotopes, respectively. Thus geologists refer to uranium-lead (two versions), potassium-argon, rubidium-strontium, or samarium-neodymium dates for rocks. Note that the carbon-14 (or radiocarbon) method is not used to date rocks because most rocks do not contain carbon. Chemical Analysis of Rocks Today Geologists can’t use just any old rock for dating. They must find rocks that have the isotopes listed above, even if these isotopes are present only in minute amounts. Most often, this is a rock body, or unit, that has formed from the cooling of molten rock material (called magma). Examples are granites (formed by cooling under the ground) and basalts (formed by cooling of lava at the earth’s surface).The next step is to measure the amount of the parent and daughter isotopes in a sample of the rock unit. Specially equipped laboratories can do this with accuracy and precision. So, in general, few people quarrel with the resulting chemical analyses.It is the interpretation of these chemical analyses that raises potential problems. To understand how geologists “read” the age of a rock from these chemical analyses, let’s use the analogy of an hourglass “clock” (Figure 2). In an hourglass, grains of fine sand fall at a steady rate from the top bowl to the bottom. After one hour, all the sand has fallen into the bottom bowl. So, after only half an hour, half the sand should be in the top bowl, and the other half should be in the bottom bowl. Suppose that a person did not observe when the hourglass was turned over. He walks into the room when half the sand is in the top bowl, and half the sand is in the bottom bowl. Most people would assume that the “clock” started half an hour earlier. By way of analogy, the sand grains in the top bowl represent atoms of the parent radioisotope (uranium-238, potassium-40, etc.) (Figure 2). The falling sand represents radioactive decay, and the sand at the bottom represents the daughter isotope (lead-206, argon-40, etc). When a geologist tests a rock sample, he assumes all the daughter atoms were produced by the decay of the parent since the rock formed. So if he knows the rate at which the parent decays, he can calculate how long it took for the daughter (measured in the rock today) to form. But what if the assumptions are wrong? For example, what if radioactive material was added to the top bowl or if the decay rate has changed? Future articles will explore the assumptions that can

lead to incorrect dates and how the creation model helps us make better sense of the patterns of radioactive “dates” we find in the rocks today.

Radiometric Dating: Problems with the Assumptions by Dr. Andrew A. Snelling on October 1, 2009; last featured August 4, 2010 Radiometric dating is often used to “prove” rocks are millions of years old. Once you understand the basic science, however, you can see how wrong assumptions lead to incorrect dates. Radiometric Dating 101 PART 1: Back to Basics PART 2: Problems with the Assumptions PART 3: Making Sense of the Patterns This three-part series will help you properly understand radiometric dating, the assumptions that lead to inaccurate dates, and the clues about what really happened in the past.Most people think that radioactive dating has proven the earth is billions of years old. Yet this view is based on a misunderstanding of how radiometric dating works. Part 1 (in the previous issue) explained how scientists observe unstable atoms changing into stable atoms in the present. Part 2 explains how scientists run into problems when they make assumptions about what happened in the unobserved past. The Hourglass “Clock”—An Analogy for Dating Rocks An hourglass is a helpful analogy to explain how geologists calculate the ages of rocks. When we look at sand in an hourglass, we can estimate how much time has passed based on the amount of sand that has fallen to the bottom. Radioactive rocks offer a similar “clock.” Radioactive atoms, such as uranium (the parent isotopes), decay into stable atoms, such as lead (the daughter isotopes), at a measurable rate. To date a radioactive rock, geologists first measure the “sand grains” in the top glass bowl (the parent radioisotope, such as uranium-238 or potassium-40).They also measure the sand grains in the bottom bowl (the daughter isotope, such as lead-206 or argon-40, respectively). Based on these observations and the known rate of radioactive decay, they estimate the time it has taken for the daughter isotope to accumulate in the rock.However, unlike the hourglass whose accuracy can be tested by turning it upside down and comparing it to trustworthy clocks, the reliability of the radioactive “clock” is subject to three unprovable assumptions. No geologist was present when the rocks were formed to see their contents, and no geologist was present to measure how fast the radioactive “clock” has been running through the millions of years that supposedly passed after the rock was formed. Assumption 1: Conditions at Time Zero No geologists were present when most rocks formed, so they cannot test whether the original rocks already contained daughter isotopes alongside their parent radioisotopes. For example, with regard to the volcanic lavas that erupted, flowed, and cooled to form rocks in the unobserved past, evolutionary geologists simply assume that none of the daughter argon-40 atoms was in the lava rocks.For the other radioactive “clocks,” it is assumed that by analyzing multiple samples of a rock body, or unit, today it is possible to determine how much of the daughter isotopes (lead, strontium, or neodymium) were present when the rock formed (via the so-called isochron technique, which is still based on unproven assumptions 2 and 3). Yet lava flows that have occurred in the present have been tested soon after they erupted, and they invariably contained much more argon-40 than expected.1 For example, when a sample of the lava in the Mt. St. Helens crater (that had been observed to form and cool in 1986) (Figure 1) was analyzed in 1996, it contained so much argon-40 that it had a calculated “age” of 350,000 years!2 Similarly, lava flows on the sides of Mt. Ngauruhoe, New Zealand (Figure 2), known to be less than 50 years old, yielded “ages” of up to 3.5 million years.3

Click here to view larger picture (PDF format). So it is logical to conclude that if recent lava flows of known age yield incorrect old potassium-argon ages due to the extra argon-40 that they inherited from the erupting volcanoes, then ancient lava flows of unknown ages could likewise have inherited extra argon-40 and yield excessively old ages. There are similar problems with the other radioactive “clocks.” For example, consider the dating of Grand Canyon’s basalts (rocks formed by lava cooling at the earth’s surface). We find places on the North Rim where volcanoes erupted after the Canyon was formed, sending lavas cascading over the walls and down into the Canyon.Obviously, these eruptions took place very recently, after the Canyon’s layers were deposited (Figure 3). These basalts yield ages of up to 1 million years based on the amounts of potassium and argon isotopes in the rocks. But when we date the rocks using the rubidium and strontium isotopes, we get an age of 1.143 billion years. This is the same age that we get for the basalt layers deep below the walls of the eastern Grand Canyon.4How could both lavas—one at the top and one at the bottom of the Canyon—be the same age based on these parent and daughter isotopes? One solution is that both the recent and early lava flows inherited the same rubidium-strontium chemistry—not age—from the same source, deep in the earth’s upper mantle. This source already had both rubidium and strontium.To make matters even worse for the claimed reliability of these radiometric dating methods, these same basalts that flowed from the top of the Canyon yield a samarium-neodymium age of about 916 million years,5 and a uranium-lead age of about 2.6 billion years!6 Assumption 2: No Contamination The problems with contamination, as with inheritance, are already well-documented in the textbooks on radioactive dating of rocks.7 Unlike the hourglass, where its two bowls are sealed, the radioactive “clock” in rocks is open to contamination by gain or loss of parent or daughter isotopes because of waters flowing in the ground from rainfall and from the molten rocks beneath volcanoes. Similarly, as molten lava rises through a conduit from deep inside the earth to be erupted through a volcano, pieces of the conduit wallrocks and their isotopes can mix into the lava and contaminate it.Because of such contamination, the less than 50-year-old lava flows at Mt. Ngauruhoe, New Zealand (Figure 4), yield a rubidium-strontium “age” of 133 million years, a samarium-neodymium “age” of 197 million years, and a uranium-lead “age” of 3.908 billion years!8 Assumption 3: Constant Decay Rate Physicists have carefully measured the radioactive decay rates of parent radioisotopes in laboratories over the last 100 or so years and have found them to be essentially constant (within the measurement error margins). Furthermore, they have not been able to significantly change these decay rates by heat, pressure, or electrical and magnetic fields. So geologists have assumed these radioactive decay rates have been constant for billions of years. However, this is an enormous extrapolation of seven orders of magnitude back through immense spans of unobserved time without any concrete proof that such an extrapolation is credible. Nevertheless, geologists insist the radioactive decay rates have always been constant, because it makes these radioactive clocks “work”!New evidence, however, has recently been discovered that can only be explained by the radioactive decay rates not having been constant in the past. 9 For example, the radioactive decay of uranium in tiny crystals in a New Mexico granite (Figure 5) yields a uranium-lead “age” of 1.5 billion years. Yet the same uranium decay also produced abundant helium, but only 6,000 years worth of that helium was found to have leaked out of the tiny crystals.This means that the uranium must have decayed very rapidly over the same 6,000 years that the helium was leaking. The rate of uranium decay must have been at least 250,000 times faster than today’s measured rate! For more details see Don DeYoung’s Thousands . . . Not Billions (Master Books, Green Forest, Arkansas, 2005), pages 65–78.The assumptions on which the radioactive dating is based are not only unprovable but plagued with problems. As this article has illustrated, rocks may have inherited parent and daughter isotopes from their sources, or they may have been contaminated when they moved through other rocks to their current locations. Or inflowing water may have mixed isotopes into the rocks. In addition, the radioactive decay rates have not been constant.So if these clocks are based on faulty assumptions and yield unreliable results, then scientists should not trust or promote the claimed radioactive “ages” of countless millions of years, especially since they contradict the true history of the universe. Radiometric Dating: Making Sense of the Patterns

by Dr. Andrew A. Snelling on January 1, 2010; last featured March 16, 2011 Radiometric dating methods sometimes yield conflicting results, but the technique itself is scientific and reliable, and once the results are interpreted in a creation framework, they yield clear patterns that help us better understand the earth’s history since creation six thousand years ago. Shop Now Radiometric Dating 101 PART 1: Radiometric Dating: Back to Basics PART 2: Radiometric Dating: Problems with the Assumptions PART 3: Making Sense of the Patterns This three-part series will help you properly understand radiometric dating, the assumptions that lead to inaccurate dates, and the clues about what really happened in the past.Part Two of this series showed that the same rocks can yield very different ages, depending on which radiometric dating technique you use. These inconsistent results are due to the problems of inheritance and contamination, which cause the rocks’ chemistry to differ from the assumptions of standard radioactive “clocks.”Furthermore, new evidence indicates that radioactive elements in the rocks, which are used to date the rocks, decayed at much faster rates during some past event (or events) in the last 6,000 years. So the claimed ages of many millions of years, which are based on today’s slow decay rates, are totally unreliable.Does this mean we should throw out the radioactive clocks? Surprisingly, they are useful!The general principles of using radioisotopes to date rocks are sound; it’s just that the assumptions have been wrong and led to exaggerated dates. While the clocks cannot yield absolute dates for rocks, they can provide relative ages that allow us to compare any two rock units and know which one formed first. They also allow us to compare rock units in different areas of the world to find which ones formed at the same time. Furthermore, if physicists examine why the same rocks yield different dates, they may discover new clues about the unusual behavior of radioactive elements during the past.With the help of this growing body of information, creation geologists hope to piece together a better understanding of the precise sequence of events in earth’s history, from Creation Week to the Flood and beyond. Different Dates for the Same Rocks Usually geologists do not use all four main radioactive clocks to date a rock unit. This is considered an unnecessary waste of time and money. After all, if these clocks really do work, then they should all yield the same age for a given rock unit. Sometimes though, using different parent radioisotopes to date different samples (or minerals) from the same rock unit does yield different ages, hinting that something is amiss.1Recently, creationist researchers have utilized all four common radioactive clocks to date the same samples from the same rock units.2 Among these were four rock units far down in the Grand Canyon rock sequence (Figure 1), chosen because they are well known and characterized. These were as follows: Radiometric Ages of Rock Samples: Figures 1 through 5, and Table 1. Click the picture to view a larger, pdf version. Cardenas Basalt (lava flows deep in the east Canyon sequence) (Figure 2). Bass Rapids diabase sill (where basalt magma squeezed between layers and cooled) (Figure 3). Brahma amphibolites (basalt lava flows deep in the Canyon sequence that later metamorphosed) (Figure 4). Elves Chasm Granodiorite (a granite regarded as the oldest Canyon rock unit) (Figure 5). Table 1 lists the dates obtained from each rock unit. Figure 6 (see below) graphically illustrates the range in the supposed ages of these rock units, obtained by utilizing all four radioactive clocks. It is immediately apparent that the ages for each rock unit do not agree. Indeed, in the Cardenas Basalt, for example, the samarium-neodymium age is three times the potassium-argon age. Nevertheless, the ages follow three obvious patterns. Two techniques (potassium-argon age and rubidiumstrontium)always yield younger ages than two other techniques (uranium-lead and samarium-neodymium). Furthermore, the potassium-argon ages are always younger than the rubidium-strontium ages. And often the samarium-neodymium ages are younger than the uranium-lead ages.What then do these patterns mean? All the radioactive clocks in each rock unit should have started “ticking” at the same time, the instant that each rock unit was formed. So how do we explain that they have each recorded different ages?The answer is simple but profound. Each of the radioactive elements must have decayed at different, faster rates in the past!In the case of the Cardenas Basalt, while the potassium-argon clock ticked through 516 million years, two other clocks ticked through 1,111 million years and 1,588 million years. So if these clocks ticked at such different rates in the past, not only are they inaccurate, but these rocks may not be millions of years old!

Patterns in the Radiometric Ages: Figures 6 and 7. Click the picture to view a larger, pdf version. But how could radioactive decay rates have been different in the past? Creationist researchers don’t fully understand yet. However, the observed age patterns provide clues. Potassium and rubidium decay radioactively by the process known as beta (β) decay, whereas uranium and neodymium decay via alpha (α) decay (Figure 6). The former always gives younger ages. We see another pattern within beta decay. Potassium today decays faster than rubidium and always gives younger ages.Both of these patterns suggest something happened in the past inside the nuclei of these parent atoms to accelerate their decay. The decay rate varied based on the stability or instability of the parent atoms. Research is continuing. Relative Ages Look again at Figure 1, which is a geologic diagram depicting the rock layers in the walls of the Grand Canyon, along with the rock units deep in the inner gorge along the Colorado River. This diagram shows that the radiometric dating methods accurately show the top rock layer is younger than the layers beneath it.That’s logical because the sediment making up that layer was deposited on top of, and therefore after, the layers below. So reading this diagram tells us basic information about the time that rock layers and rock units were formed relative to other layers.Based on the radioactive clocks, we can conclude that these four rock units deep in the gorge (Table 1) are all older in a relative sense than the horizontal sedimentary layers in the Canyon walls. Conventionally the lowermost or oldest of these horizontal sedimentary layers is labeled early to middle Cambrian3 and thus regarded as about 510–520 million years old.4 All the rocks below it are then labeled Precambrian and regarded as older than 542 million years.So accordingly all four dated rock units (Table 1) are also Precambrian. And apart from the potassium-argon age for the Cardenas Basalt, all the radioactive clocks have correctly shown that these four rock units were formed earlier than Cambrian, so they are pre-Cambrian. (But the passage of time between these Precambrian rock units and the horizontal sedimentary layers above them was a maximum of about 1,700 years—the time between creation and the Flood—not millions of years.)Similarly, in the relative sense the Brahma amphibolites and Elves Chasm Granodiorite are older (by hours or days) than the Cardenas Basalt and Bass Rapids diabase sill (Figure 1). Once again, the radioactive clocks have correctly shown that those two rock units are older than the rock units above them.Why then should we expect the radioactive clocks to yield relative ages that follow a logical pattern? (Actually, younger sedimentary layers yield a similar general pattern,5 Figure 7.) The answer is again simple but profound! The radioactive clocks in the rock units at the bottom of the Grand Canyon, formed during Creation Week, have been ticking for longer than the radioactive clocks in the younger sedimentary layers higher up in the sequence that were formed later during the Flood. Conclusion Although it is a mistake to accept radioactive dates of millions of years, the clocks can still be useful to us, in principle, to date the relative sequence of rock formation during earth history.The different clocks have ticked at different, faster rates in the past, so the standard old ages are certainly not accurate, correct, or absolute. However, because the radioactive clocks in rocks that formed early in earth history have been ticking longer, they should generally yield older radioactive ages than rock layers formed later.So it is possible that relative radioactive ages of rocks, in addition to mineral contents and other rock features, could be used to compare and correlate similar rocks in other areas to find which ones formed at the same time during the earth history. Radioactive “Dating” Failure Recent New Zealand Lava Flows Yield “Ages” of Millions of Years by Dr. Andrew A. Snelling on December 1, 1999 Originally published in Creation 22, no 1 (December 1999): 18-21. Recent New Zealand lava flows yield ‘ages’ of millions of years. Standing roughly in the centre of New Zealand’s North Island, Mt Ngauruhoe is New Zealand’s newest volcano and one of the most active (Figures 1 and 2). It is not as well publicized as its larger close neighbour MT Ruapehu, which has erupted briefly several times in the last five years.However, Mt Ngauruhoe is an imposing, almost perfect cone that rises more than 1,000 metres (3,300 feet) above the surrounding landscape to an elevation of 2,291 m (7,500 feet) above sea level1 (Figure 3). Eruptions from a central 400 m (1,300 foot) wide crater have constructed the cone’s steep (33°) outer slopes. Figure 1. The location of Mt Ngauruhoe, central North Island, New Zealand. (click image for larger view) Mt Ngauruhoe is thought to have been active for at least 2,500 years, with more than 70 eruptive periods since 1839, when European settlers first recorded a steam eruption.2 Of

course, before that, the Maoris witnessed many eruptions from the mountain. The first lava eruption seen by Europeans occurred in 1870.3 Then there were ash eruptions every few years until a major explosive eruption in April–May 1948, followed by lava flowing down the northwestern slopes in February 1949.4,5 The estimated lava volume was about 575,000 cubic metres (20 million cubic feet). Figure 2. Aerial view, looking south at sunrise, of volcanoes Mt Ngauruhoe (foreground) and MT Ruapehu (background). The eruption lasting from 13 May 1954 to 10 March 1955 began with an explosive ejection of ash and blocks.6,7 Then almost 8 million cubic metres (280 million cubic feet) of lava flowed from the crater in a series of 17 distinct flows on the following 1954 dates: June 4, 30 July 8, 9, 10, 11, 13, 14, 23, 28, 29, 30 August 15(?), 18 September 16, 18, 26 These flows are still distinguishable today on the northwestern and western slopes of Ngauruhoe (Figure 4). The 18 August flow was more than 18 m (55 feet) thick and still warm almost a year after congealing. Explosions of ash completed this long eruptive period. Figure 3. Mt Ngauruhoe as seen looking north from near MT Ruapehu. Afterwards, Ngauruhoe steamed almost continuously, with many small ash eruptions8 (Figure 5). Cannon-like, highly explosive eruptions in January and March 1974 threw out large quantities of ash as a column into the atmosphere, and as avalanches flowing down the cone’s sides. Blocks weighing up to 1,000 tonnes were hurled 100 m (330 feet). However, the most violent explosions occurred on 19 February 1975, accompanied by what eye-witnesses described as atmospheric shock waves.9 Blocks up to 30 m (100 ft) across were catapulted up to 3 km (almost 2 miles). The eruption plume was 11–13 km (7–8 miles) high.Turbulent avalanches of ash and blocks swept down Ngauruhoe’s sides at about 60 km (35 miles) per hour.10 It is estimated that at least 3.4 million cubic metres (120 million cubic feet) of ash and blocks were ejected in 7 hours.11up> No further eruptions have occurred since. Dating the rocks Figure 4. View from the Mangateopopo Valley at the base of Mt Ngauruhoe, showing the darkercoloured recent lava flows on its northwestern slopes. Radioactive dating in general depends on three major assumptions: When the rock forms (hardens) there should only be parent radioactive atoms in the rock and no daughter radiogenic (derived by radioactive decay of another element) atoms;512After hardening, the rock must remain a closed system, that is, no parent or daughter atoms should be added to or removed from the rock by external influences such as percolating groundwaters; and The radioactive decay rate must remain constant. If any of these assumptions are violated, then the technique fails and any “dates” are false. The potassium-argon (K–Ar) dating method is often used to date volcanic rocks (and by extension, nearby fossils). In using this method, it is assumed that there was no daughter radiogenic argon ( 40Ar*) in rocks when they formed.13 For volcanic rocks which cool from molten lavas, this would seem to be a reasonable assumption. Because argon is a gas, it should escape to the atmosphere due to the intense heat of the lavas. Of course, no geologist was present to test this assumption by observing ancient lavas when they cooled, but we can study modern lava flows. Potassium-argon “dates” Figure 5. Small ash eruption, Mt Ngauruhoe. Figure 6. Inset: Andesite of the June 30, 1954 flow, Mt Ngauruhoe, seen at 60 times magnification under a geological microscope. Different minerals have different colours. All are embedded in a fine-grained matrix.Eleven samples were collected from five recent lava flows during field work in January 1996—two each from the 11 February 1949, 4 June 1954, and 14 July 1954 flows and from the 19 February 1975 avalanche deposits, and three from the 30 June 1954 flow14 (Figure 6). The darker recent lavas were clearly visible and each one easily identified (with the aid of maps) on the northwestern slopes against the lighter-coloured older portions of the cone (Figures 4 and 7). All flows were typically made up of jumbled blocks of congealed lava, resulting in rough, jagged, clinkery surfaces (Figure 8). The samples were sent progressively in batches to Geochron Laboratories in Cambridge, Boston (USA), for whole-rock potassium-argon (K–Ar) dating—first a piece of one sample from each flow, then a piece of the second sample from each flow after the first set of results was received, and finally, a piece of the third sample from the 30 June 1954 flow.15 To also test the consistency of results within samples, second pieces of two of the 30 June 1954 lava samples were also sent for analysis.Geochron is a respected commercial laboratory, the K–Ar lab manager having a Ph.D. in K–Ar dating. No specific location or expected age information was supplied to the laboratory. However, the samples were described as probably young with very little argon in them so as to ensure extra care was taken during the analytical work. Figure 7. Map of the northwestern slopes of Mt Ngauruhoe showing the lava flows of 1949 and 1954, and the 1975 avalanche deposits.3,4 (Click image for larger view) The “dates” obtained from the K–Ar analyses are listed in Table 1.16 The “ages” range from 3.15 Pb–Pb

4.567

0.0007

Assuming primordial Pb

Amelin et al. 2002

model age

CAI TS32, Type CTA, >3.15 Pb–Pb

4.5669

0.0008

Assuming primordial Pb

Amelin et al. 2002

model age

CAI TS33, Type B1, >3.15 Pb–Pb

4.5676

0.0009

Assuming primordial Pb

Amelin et al. 2002

model age

CAI F2, Type B2, 2.85–3.15 Pb–Pb

4.5663

0.0008

Assuming primordial Pb

Amelin et al. 2002

model age

CAI TS32, Type CTA, 2.85–3.15 Pb–Pb

4.5678

0.0008

Assuming primordial Pb

Amelin et al. 2002

model age

CAI TS33, Type B1, 2.85–3.15 Pb–Pb

4.5667

0.0007

Assuming primordial Pb

Amelin et al. 2002

model age

CAI F2, Type B2, >3.15 Pb–Pb

4.5675

0.001

Assuming common Pb

Amelin et al. 2002

model age

CAI TS32, Type CTA, >3.15 Pb–Pb

4.5679

0.0017

Assuming common Pb

Amelin et al. 2002

model age

CAI TS33, Type B1, >3.15 Pb–Pb

4.5686

0.0018

Assuming common Pb

Amelin et al. 2002

model age

CAI F2, Type B2, 2.85–3.15 Pb–Pb

4.5671

0.0015

Assuming common Pb

Amelin et al. 2002

model age

CAI TS32, Type CTA, 2.85–3.15 Pb–Pb

4.5682

0.001

Assuming common Pb

Amelin et al. 2002

model age

CAI TS33, Type B1, 2.85–3.15 Pb–Pb

4.5678

0.0019

Assuming common Pb

Amelin et al. 2002

model age

model age

207

Pb–206Pb 4.5679

0.0005

Mean of six ages on three inclusions with Canyon Diablo troilite Amelin et al. 2002

inclusions

207

Pb–206Pb 4.5336

0.0011

F2 plagioclase rich

Connelly et al. 2008

model age

inclusions

207

Pb–206Pb 4.5664

0.0008

F2 melilite rich

Connelly et al. 2008

model age

inclusions

207

Pb–206Pb 4.5664

0.0008

F2 pyroxene rich

Connelly et al. 2008

model age

inclusions

207

Pb–206Pb 4.5663

0.0016

TS32 plagioclase rich

Connelly et al. 2008

model age

inclusions

207

Pb– Pb 4.5678

0.0008

TS32 melilite rich

Connelly et al. 2008

model age

inclusions

207

Pb–206Pb 4.5669

0.0008

TS32 pyroxene rich

Connelly et al. 2008

model age

inclusions

207

Pb– Pb 4.5580

0.0020

TS33 plagioclase rich

Connelly et al. 2008

model age

inclusions

207

Pb–206Pb 4.5668

0.0007

TS33 melilite rich

Connelly et al. 2008

model age

inclusions

207

Pb–206Pb 4.5676

0.0009

TS33 pyroxene rich

Connelly et al. 2008

model age

207

Pb–206Pb 4.56759

0.0001

Acid–leached residues (3) +Bouvier, Vervoort, and leachate Patchett 2008 model age

207

Pb–206Pb 4.5668

0.0004

AJEF Pyroxene

Jacobsen et al. 2008

model age

207

Pb–206Pb 4566.6

0.0007

AJEF Metilite coarse

Jacobsen et al. 2008

model age

207

Pb–206Pb 4.5677

0.0006

AJEF 1.8 A m medium–coarse

Jacobsen et al. 2008

model age

207

Pb–206Pb 4.5696

0.0009

AJEF Pyroxene first wash

Jacobsen et al. 2008

model age

207

Pb–206Pb 4.5659

0.001

AJEF wash

Jacobsen et al. 2008

model age

inclusions (Ca– Al)

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

206

206

Pyroxene

+

nm

second

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al) inclusions (Ca– Al)

207

Pb–206Pb 4.5667

0.0004

A43 Pyroxene from 0.4–1.1 A Jacobsen et al. 2008

model age

207

Pb–206Pb 4.5682

0.0039

A43 0.4–1.1 A mag med– coarse Jacobsen et al. 2008

model age

207

Pb–206Pb 4.5656

0.0027

A43 0.4–1.1 A mag med– fine Jacobsen et al. 2008

model age

207

Pb–206Pb 4.5659

0.0014

A43 0.4–1.1 A mag

model age

207

Pb–206Pb 4.568

0.003

MNHN–A residue Canyon Diablo troilite

withBouvier, Vervoort, and Patchett 2008 model age

Pb–206Pb 4.5715

0.0005

MNHN–A leachate 1

residue

207

withBouvier, Vervoort, and Patchett 2008 model age

Pb–206Pb 4.5482

0.0005

MNHN–A leachate 2

residue

207

withBouvier, Vervoort, and Patchett 2008 model age

207

Pb–206Pb 4.5222

0.003

MNHN–B residue Canyon Diablo troilite

withBouvier, Vervoort, and Patchett 2008 model age

Pb–206Pb 4.5188

0.029

MNHN–B leachate 1

residue

207

withBouvier, Vervoort, and Patchett 2008 model age

Pb–206Pb 4.4914

0.0046

MNHN–B leachate 2

residue

207

withBouvier, Vervoort, and Patchett 2008 model age

207

Pb–206Pb 4.5657

0.0023

UCLA–A residue Canyon Diablo troilite

withBouvier, Vervoort, and Patchett 2008 model age

Pb–206Pb 4.566

0.0023

UCLA–A leachate 1

residue

207

withBouvier, Vervoort, and Patchett 2008 model age

Pb–206Pb 4.5603

0.0033

UCLA–A leachate 2

residue

207

withBouvier, Vervoort, and Patchett 2008 model age

207

Pb–206Pb 4.5655

0.0023

UCLA–B residue withBouvier, Vervoort, and Canyon Diablo troilite Patchett 2008 model age

207

Pb–206Pb 4.5659

0.0023

UCLA–B residue withBouvier, Vervoort, and leachate 1 Patchett 2008 model age

207

Pb–206Pb 4.57

0.0036

UCLA–B residue withBouvier, Vervoort, and leachate 2 Patchett 2008 model age

207

Pb–206Pb 4.5646

0.0029

UCLA–C residue withBouvier, Vervoort, and Canyon Diablo troilite Patchett 2008 model age

207

Pb–206Pb 4.5653

0.003

UCLA–C residue withBouvier, Vervoort, and leachate 1 Patchett 2008 model age

207

Pb–206Pb 4.5685

0.0042

UCLA–C residue withBouvier, Vervoort, and leachate 2 Patchett 2008 model age

Jacobsen et al. 2008

inclusions

Pb–Pb

4.56857

0.00087

Mean of A004 third washes Amelin et al. 2010

model age

inclusions

Pb–Pb

4.56702

0.00022

Mean of A003 and A005 residues Amelin et al. 2010

model age

inclusions

Pb–Pb

4.56664

0.00033

Mean of residues

Amelin et al. 2010

model age

inclusion

232

White

Chen and Tilton 1976

model age

inclusion

232

Th– Pb 4.063

Pink

Chen and Tilton 1976

model age

inclusion

238

U–206Pb 4.023

White

Chen and Tilton 1976

model age

inclusion

238

U–206Pb 4.644

Pink

Chen and Tilton 1976

model age

inclusion

238

U–206Pb 4.73

Coarse–grained

Chen and Wasserburg 1981 model age

inclusion

238

U–206Pb 5.31

Coarse–grained

Chen and Wasserburg 1981 model age

inclusion

238

U–206Pb 4.83

Coarse–grained

Chen and Wasserburg 1981 model age

Th–208Pb 3.773 208

A004

inclusion

238

U–206Pb 13.0

Fine–grained

Chen and Wasserburg 1981 model age

inclusion

238

U–206Pb 5.0

Fine–grained

Chen and Wasserburg 1981 model age

inclusion

238

U–206Pb 4.56

Coarse–grained

Chen and Wasserburg 1981 model age

inclusion

238

U–206Pb 4.59

Coarse–grained

Chen and Wasserburg 1981 model age

inclusion

238

U–206Pb 16.7

Fine–grained

Chen and Wasserburg 1981 model age

238

U–206Pb 4.301

AJEF Pyroxene first wash Jacobsen et al. 2008

model age

238

U–206Pb 4.34

AJEF Pyroxene second wash Jacobsen et al. 2008

model age

238

U–206Pb 4.761

AJEF 1.8 A m + nm medium–coarse Jacobsen et al. 2008

model age

238

U–206Pb 4.827

A43 Pyroxene from 0.4–1.1 A Jacobsen et al. 2008

model age

238

U–206Pb 4.741

A43 0.4–1.1 A mag med–coarse Jacobsen et al. 2008

model age

238

U–206Pb 4.663

A43 0.4–1.1 A mag med–fine Jacobsen et al. 2008

model age

238

U–206Pb 4.858

A43 0.4–1.1 A mag

Jacobsen et al. 2008

model age

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca–

inclusion Al)

(Ca– 207

inclusion

235U– Pb4.385

White

Chen and Tilton 1976

model age

inclusion

235U–207Pb4.583

Pink

Chen and Tilton 1976

model age

CAI F2, Type B2, >3.15 U–Pb

4.564

0.029

Amelin et al. 2002

model age

CAI TS32, Type CTA, >3.15 U–Pb

4.604

0.01

Amelin et al. 2002

model age

CAI TS33, Type B1, >3.15 U–Pb

4.67

0.016

Amelin et al. 2002

model age

CAI F2, Type B2, 2.85–3.15 U–Pb

4.762

0.038

Amelin et al. 2002

model age

CAI TS32, Type CTA, 2.85–3.15 U–Pb

4.573

0.009

Amelin et al. 2002

model age

CAI TS33, Type B1, 2.85–3.15 U–Pb

4.716

0.02

Amelin et al. 2002

model age

inclusions (Ca– Al) U–Pb inclusions (Ca– Al) U–Pb

4.5666

4.5675

concordia intercept)

age

(upper

0.0013

CAIs AJEF & A43 residues & px second washes Jacobsen et al. 2008

concordia intercept)

age

(upper

0.0012

CAIs AJEF & A43 residues & px second washes Jacobsen et al. 2008

0.0001

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

0.0002

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

0.0002

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

0.0003

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

Calibrated by Pb–Pb Ages

dark inclusions

dark inclusions

dark inclusions

dark inclusions

I–Xe

I–Xe

I–Xe

I–Xe

4.5645

4.5649

4.5641

4.5652

inclusions (Ca– Al) I–Xe inclusions (Ca– Al) I–Xe inclusions (Ca– Al) I–Xe

4.5629

4.563

4.5623

0.0002

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

0.0002

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

0.0002

Relative to Shallowater absolute I–Xe age Pravdivtseva et al. 2003 model age

Table 4. Model ages for whole-rock, matrix and other samples of the Allende CV3 carbonaceous chondrite meteorite, with the details and literature sources. Sample

Method

Age

Error +/–

Notes

Source

Type

β–Decayers whole rock

40

whole rock

Ar–39Ar

4.57

0.03

Sample 2

Jessberger et al. 1980

plateau age

K–Ar

4.43

0.10

Fine–grained

Dominik and Jessberger 1979 model age

matrix

K–Ar

3.34

0.02

Sample 3915

Herzog et al. 1980

total fusion model age

matrix

K–Ar

3.58

0.02

Sample 3915

Herzog et al. 1980

total fusion model age

matrix

K–Ar

3.43

0.04

Sample 3915

Herzog et al. 1980

total fusion model age

matrix

K–Ar

3.63

0.05

Sample 3915

Herzog et al. 1980

total fusion model age

matrix

K–Ar

3.99

0.01

Sample 3915

Herzog et al. 1980

total fusion model age

granular material

K–Ar

6.29

0.01

Sample 3915

Herzog et al. 1980

total fusion model age

granular material

K–Ar

4.11

0.02

Sample 3915

Herzog et al. 1980

total fusion model age

anorthite

K–Ar

14.2

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

anorthite

K–Ar

8.5

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

anorthite

K–Ar

6.2

1.1

Sample 3529Z

Herzog et al. 1980

total fusion model age

anorthite

K–Ar

14.5

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

pyroxene

K–Ar

8.5

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

pyroxene

K–Ar

5.3

0.9

Sample 3529Z

Herzog et al. 1980

total fusion model age

pyroxene

K–Ar

8.2

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

melilite

K–Ar

6.0

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

melilite

K–Ar

5.4

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

fine–grained material

K–Ar

8.8

1.3

Sample 3529Z

Herzog et al. 1980

total fusion model age

fine–grained material

K–Ar

6.8

0.9

Sample 3529Z

Herzog et al. 1980

total fusion model age

fine–grained material

K–Ar

7.6

0.9

Sample 3529Z

Herzog et al. 1980

total fusion model age

vein

K–Ar

7.97

0.6

Sample 3655A

Herzog et al. 1980

total fusion model age

vein

K–Ar

5.10

0.17

Sample 3655A

Herzog et al. 1980

total

fusion

model age vein

K–Ar

4.30

0.03

Sample 3655A

Herzog et al. 1980

total fusion model age

vein

K–Ar

4.86

0.04

Sample 3655A

Herzog et al. 1980

total fusion model age

vein

K–Ar

7.12

0.9

Sample 3655A

Herzog et al. 1980

total fusion model age

spinel

K–Ar

6.46

0.6

Sample 3655A

Herzog et al. 1980

total fusion model age

spinel

K–Ar

7.33

1.2

Sample 3655A

Herzog et al. 1980

total fusion model age

spinel

K–Ar

6.13

0.46

Sample 3655A

Herzog et al. 1980

total fusion model age

spinel

K–Ar

9.37

1

Sample 3655A

Herzog et al. 1980

total fusion model age

melilite

K–Ar

10.90

1.3

Sample 3655A

Herzog et al. 1980

total fusion model age

melilite

K–Ar

16.24

1.3

Sample 3655A

Herzog et al. 1980

total fusion model age

melilite

K–Ar

10.07

1.34

Sample 3655A

Herzog et al. 1980

total fusion model age

melilite

K–Ar

14.80

1.34

Sample 3655A

Herzog et al. 1980

total fusion model age

pyroxene

K–Ar

13.50

1.3

Sample 3655A

Herzog et al. 1980

total fusion model age

pyroxene

K–Ar

9.3

1.3

Sample 3655A

Herzog et al. 1980

total fusion model age

pyroxene

K–Ar

8.87

1.34

Sample 3655A

Herzog et al. 1980

total fusion model age

rim

K–Ar

4.09

0.02

Sample 3655A

Herzog et al. 1980

total fusion model age

rim

K–Ar

4.01

0.02

Sample 3655A

Herzog et al. 1980

total fusion model age

rim

K–Ar

4.18

0.01

Sample 3655A

Herzog et al. 1980

total fusion model age

inner part of vein K–Ar

16.83

1.34

Sample 3655A

Herzog et al. 1980

total fusion model age

fine–grained material

K–Ar

9.18

1.32

Sample 3655A

Herzog et al. 1980

total fusion model age

matrix

K–Ar

3.80

0.09

Sample 1

Jessberger et al. 1980

model age

whole rock

K–Ar

4.43

0.09

Sample 2

Jessberger et al. 1980

model age

4.52

0.04

A6 a

Gray, Papanastassiou, Wasserburg 1973

and

total meteorite Rb–Sr

4.55

0.04

A6 b

Gray, Papanastassiou, Wasserburg 1973

and

total meteorite Rb–Sr

4.56

0.03

A6 s1

Gray, Papanastassiou, Wasserburg 1973

and

total meteorite Rb–Sr

4.59

0.03

A6 s2

Gray, Papanastassiou, Wasserburg 1973

and

total meteorite Rb–Sr

4.56

0.04

A6 s3

Gray, Papanastassiou, Wasserburg 1973

and

total meteorite Rb–Sr Rb–Sr

4.48

Tatsumoto, Unruh, Desborough1976

and

whole rock

Rb–Sr

4.49

Tatsumoto, Unruh, Desborough1976

and

whole rock

model age model age model age model age model age model age model age

Rb–Sr

4.84

Tatsumoto, Unruh, Desborough1976

and

matrix

Rb–Sr

4.60

Tatsumoto, Unruh, Desborough1976

and

matrix

Rb–Sr

3.33

White

Tatsumoto, Unruh, Desborough1976

and

aggregate

Rb–Sr

4.41

Pinkish–white

Tatsumoto, Unruh, Desborough1976

and

aggregate whole rock

Rb–Sr

4.56

WR1

Shimoda et al. 2005

model age

whole rock

Rb–Sr

4.58

WR2

Shimoda et al. 2005

model age

model age

model age model age model age model age

α–Decayers 207

whole rock

206 207

whole rock

206 207

whole rock

206 207

whole rock

206 207

aggregate

206 207

whole rock

206 207

matrix

206 207

matrix

206 207

matrix

206 207

matrix

206 207

matrix

206 207

magnetic

206 207

magnetic

206 207

magnetic

206 207

aggregate

206 207

aggregate

206 207

aggregate

206 207

aggregate

206 207

matrix

206 207

matrix

206 207

A003 1W1

206

A003 1W1 + extra HBr

207 206

Pb– Pb

4.528

0.04

Huey and Kohman 1973

Pb– Pb

4.496

0.01

Tatsumoto, Knight, and Allègre 1973 model age

Pb– Pb

4.51

Tilton 1973

model age

Pb– Pb

4.52

Tilton 1973

model age

Pb– Pb

4.562

Chen and Tilton 1976

model age

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.496

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.494

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.481

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.489

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.506

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.524

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.467

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.492

Pb– Pb

Tatsumoto, Unruh, Desborough1976

and

4.483

Pb– Pb

White

Tatsumoto, Unruh, Desborough1976

and

4.557

Pb– Pb

White

Tatsumoto, Unruh, Desborough1976

and

4.562

Pb– Pb

Pinkish

Tatsumoto, Unruh, Desborough1976

and

4.547

Pb– Pb

Pinkish

Tatsumoto, Unruh, Desborough1976

and

4.533

Pb– Pb

C3 same sample

Tatsumoto, Unruh, Desborough1976

and

4.49

Pb– Pb

C3 same sample

Tatsumoto, Unruh, Desborough1976

and

4.52

Pb– Pb

4.54569

0.0027

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.54968

0.00186

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

White

model age model age model age model age model age model age model age model age model age model age model age model age model age model age model age

207

A004 2W1

206 207

A004 3W1

206 207

A004 4W1

206 207

A004 5W1

206 207

A005 6W1

206 207

A005 7W1

206 207

A005 8W1

206 207

A005 9W1

206 207

A003 1W2

206

A003 1W2 + extra HBr

207 206 207

A004 2W2

206 207

A004 4W2

206 207

A004 5W2

206 207

A005 6W2

206 207

A005 7W2

206 207

A005 8W2

206 207

A005 9W2

206 207

A004 2W3

206 207

A004 3W3

206 207

A004 4W3

206 207

A004 5W3

206

A003 1R Medium–fine “whole rock”

207

A003 1R+ (aliquot 2 + extra HBr)

207

A004 2R Coarse pyroxene–rich

207

A004 3R Coarse melilite and feldspar–rich A004 4R Coarse “whole

206

206

206

207 206 207 206

Pb– Pb

4.55967

0.00861

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.55548

0.00507

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.54045

0.00276

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.53429

0.00209

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.55282

0.00555

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.55808

0.00235

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.53446

0.00244

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.55494

0.00164

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56563

0.00143

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56748

0.00159

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56847

0.00114

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56926

0.00187

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56756

0.00101

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.50331

0.00358

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56954

0.00137

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56872

0.00206

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.57021

0.00101

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.57036

0.00175

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56837

0.00033

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56905

0.00047

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56758

0.00103

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56679

0.00025

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56697

0.00024

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56697

0.00029

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56643

0.00017

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

4.5667

0.00018

Pb– Pb

Assuming primordial isotopicAmelin et al. 2010 composition of initial Pb

model age

rock” A004 5R Medium–fine “whole rock”

207

A005 6R Medium–fine dark

207

A005 7R Medium–fine light

207

A005 8R “whole rock”

206

206

206

Pb– Pb

4.56671

0.00023

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56781

0.00044

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Pb– Pb

4.56712

0.0003

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010

model age

Fine

207 206

A005 9R Very fine “whole rock”

207

A004 2R+W3 recombined

207

A004 3R+W3 recombined

207

A004 4R+W3 recombined

207

A004 5R+W3 recombined

207

A003 Frac.1 recombined

207

A003 Frac.1+ recombined

207

A004 Frac.2 recombined

207

A004 Frac.3 recombined

207

A004 Frac.4 recombined

207

A004 Frac.5 recombined

207

A005 Frac.6 recombined

207

A005 Frac.7 recombined

207

A005 Frac.8 recombined

207

A005 Frac.9 recombined

207

206

206

206

206

206

206

206

206

206

206

206

206

206

206

206 207

A004 3W1

206 207

A004 5W1

206 207

A005 7W1

206 207

A005 9W1

206 207

A003 1W2

206

A003 1W2 + extra HBr

207 206 207

A004 2W2

206

Pb– Pb

4.56714

0.00028

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56725

0.00033

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56787

0.00068

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56701

0.00021

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.5673

0.00025

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56699

0.00049

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56314

0.00077

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56413

0.00064

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56717

0.0015

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56595

0.00066

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56453

0.00077

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56047

0.00088

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.5297

0.00287

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56594

0.00079

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56079

0.00094

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56455

0.00077

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.75219

0.00657

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

6.14348

0.07377

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.80634

0.00291

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.87254

0.00258

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.65712

0.00142

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.65956

0.00195

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.61145

0.00096

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

207 206

A004 4W2

207 206

A004 5W2

207 206

A005 6W2

207 206

A005 7W2

207 206

A005 8W2

207 206

A005 9W2

207 206

A004 2W3

207 206

A004 3W3

207 206

A004 4W3

207

A004 5W3

206

A003 1R Medium– fine “whole rock”

207

A003 1R+ (aliquot 2 + extra HBr)

207

A004 2R Coarse pyroxene–rich

207

A004 3R Coarse melilite and feldspar–rich

206

206

206

207 206

A004 4R Coarse “whole rock”

207

A004 5R Medium– fine “whole rock”

207

A005 6R Medium– fine dark

207

A005 7R Medium– fine light

207

A005 8R “whole rock”

207

Fine

206

206

206

206

206

A005 9R Very fine “whole rock”

207

A004 2R+W3 recombined

207

A004 3R+W3 recombined

207

A004 4R+W3 recombined

207

A004 5R+W3 recombined

207

A003 Frac.1 recombined

207

A003 Frac.1+ recombined

207

A004 Frac.2 recombined

207

A004

207

Frac.3

206

206

206

206

206

206

206

206

Pb– Pb

4.69912

0.00217

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.59785

0.00082

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

5.41676

0.04032

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.61215

0.00121

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.59428

0.00184

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.59091

0.00073

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.57146

0.00155

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56929

0.0003

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.57121

0.00044

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56825

0.00101

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56755

0.00022

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.5677

0.00021

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56751

0.00022

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56669

0.0001

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56722

0.00014

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56708

0.00013

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56822

0.00019

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56733

0.00021

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56733

0.00013

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56754

0.0002

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56856

0.00058

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56747

0.00016

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56823

0.00022

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.56746

0.00041

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

3.81054

0.0003

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

3.81241

0.00034

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb– Pb

4.13562

0.00058

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Pb–

4.5844

0.00075

Assuming primordial isotopicAmelin et al. 2010 model age

recombined

206

Pb

A004 Frac.4 recombined

207

Pb– Pb

4.0668

0.00048

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

A004 Frac.5 recombined

207

Pb– Pb

4.8893

0.01526

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

A005 Frac.6 recombined

207

Pb– Pb

4.44588

0.02266

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

A005 Frac.7 recombined

207

Pb– Pb

4.61371

0.0008

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

A005 Frac.8 recombined

207

Pb– Pb

3.65461

0.00033

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

A005 Frac.9 recombined

207

Pb– Pb

4.64884

0.00089

Assuming primordial isotopic composition of initial Pb Amelin et al. 2010 model age

Th– Pb

4.391

206

206

206

206

206

206 232

aggregate

208

composition of initial Pb

Chen 1976

White

whole rock

10.40

9.86

Tatsumoto, Unruh, and Desborough 1976 model age

16.49

Tatsumoto, Unruh, and Desborough 1976 model age

9.15

Tatsumoto, Unruh, and Desborough 1976 model age

232

matrix

Th– 208 Pb 232

matrix

Th– 208 Pb 232

matrix

Th– 208 Pb 232

magnetic

208 232

magnetic

208 232

aggregate

208 232

model age

Tatsumoto, Unruh, and Desborough 1976 model age

232

Th– 208 Pb

and Tilton

Th– Pb

Tatsumoto, Unruh, Desborough 1976

and

4.81

Th– Pb

Tatsumoto, Unruh, Desborough 1976

and

10.1

Th– Pb

White

Tatsumoto, Unruh, Desborough 1976

and

5.15

Th– Pb

Pinkish

Tatsumoto, Unruh, Desborough 1976

and

5.44

White

Chen and Tilton 1976

model age model age model age

aggregate

208

aggregate

238

U–206Pb4.349

238

U–206Pb8.82

Tatsumoto, Unruh, Desborough 1976

and

whole rock

238

U–206Pb6.44

Tatsumoto, Unruh, Desborough 1976

and

matrix

238

U–206Pb6.33

Tatsumoto, Unruh, Desborough 1976

and

matrix

238

U–206Pb6.42

Tatsumoto, Unruh, Desborough 1976

and

matrix

238

U–206Pb7.80

Tatsumoto, Unruh, Desborough 1976

and

matrix

238

U–206Pb5.45

Tatsumoto, Unruh, Desborough 1976

and

matrix

238

U–206Pb4.41

Tatsumoto, Unruh, Desborough 1976

and

magnetic

238

U–206Pb7.75

Tatsumoto, Unruh, Desborough 1976

and

magnetic

238

U–206Pb7.82

Tatsumoto, Unruh, Desborough 1976

and

magnetic

238

U–206Pb4.96

Tatsumoto, Unruh, Desborough 1976

and

aggregate

White

model age model age model age model age model age model age model age model age model age model age model age model age

238

U–206Pb4.92

White

Tatsumoto, Unruh, Desborough 1976

and

aggregate

238

U–206Pb5.73

Pinkish

Tatsumoto, Unruh, Desborough 1976

and

aggregate

238

U–206Pb5.50

Pinkish

Tatsumoto, Unruh, Desborough 1976

and

aggregate A003 1W1

238

U–206Pb4.2287

A003 1W1 + extra HBr

238

A004 2W1

model age model age model age

Amelin et al. 2010

model age

U– Pb4.2333

Amelin et al. 2010

model age

238

U–206Pb5.0618

Amelin et al. 2010

model age

A004 3W1

238

U–206Pb3.5471

Amelin et al. 2010

model age

A004 4W1

238

U–206Pb4.1125

Amelin et al. 2010

model age

A004 5W1

238

U–206Pb4.6855

Amelin et al. 2010

model age

A005 6W1

238

U– Pb4.1773

Amelin et al. 2010

model age

A005 7W1

238

U–206Pb4.029

Amelin et al. 2010

model age

A005 8W1

238

U– Pb4.4346

Amelin et al. 2010

model age

A005 9W1

238

U–206Pb4.1142

Amelin et al. 2010

model age

A003 1W2

238

U–206Pb3.634

Amelin et al. 2010

model age

A003 1W2 + extra HBr

238

U–206Pb3.6411

Amelin et al. 2010

model age

A004 2W2

238

U–206Pb3.7778

Amelin et al. 2010

model age

A004 4W2

238

U– Pb3.8166

Amelin et al. 2010

model age

A004 5W2

238

U–206Pb3.9313

Amelin et al. 2010

model age

A005 6W2

238

U– Pb11.6247

Amelin et al. 2010

model age

A005 7W2

238

U–206Pb4.1284

Amelin et al. 2010

model age

A005 8W2

238

U–206Pb3.8734

Amelin et al. 2010

model age

A005 9W2

238

U–206Pb4.0317

Amelin et al. 2010

model age

A004 2W3

238

U–206Pb4.3613

Amelin et al. 2010

model age

A004 3W3

238

U– Pb4.3663

Amelin et al. 2010

model age

A004 4W3

238

U–206Pb4.316

Amelin et al. 2010

model age

A004 5W3

238

U– Pb4.3897

Amelin et al. 2010

model age

238

U–206Pb4.772

Amelin et al. 2010

model age

238

U–206Pb4.7727

Amelin et al. 2010

model age

238

U–206Pb4.9657

Amelin et al. 2010

model age

238

U–206Pb5.0338

Amelin et al. 2010

model age

238

U–206Pb4.963

Amelin et al. 2010

model age

238

U–206Pb5.0656

Amelin et al. 2010

model age

A005 6R Medium–fine dark

238

U–206Pb4.7688

Amelin et al. 2010

model age

A005 7R Medium–fine light

238

U–206Pb4.7881

Amelin et al. 2010

model age

A005 8R Fine “whole rock”

238

U–206Pb4.8041

Amelin et al. 2010

model age

238

U–206Pb4.8472

Amelin et al. 2010

model age

A004 2R+W3 recombined

238

U–206Pb4.8047

Amelin et al. 2010

model age

A004 3R+W3 recombined

238

Amelin et al. 2010

model age

A003 1R “whole rock”

206

206

206

206

206

Coarse

A004 3R Coarse melilite and feldspar–rich A004 4R Coarse “whole rock” A004 5R “whole rock”

206

Medium–fine

A003 1R+ (aliquot 2 + extra HBr) A004 2R pyroxene–rich

206

Medium–fine

A005 9R Very fine “whole rock”

206

U– Pb4.834

A004 4R+W3 recombined

238

U–206Pb4.7986

Amelin et al. 2010

model age

A004 5R+W3 recombined

238

U–206Pb4.8475

Amelin et al. 2010

model age

A003 Frac.1 recombined

238

U– Pb4.5705

Amelin et al. 2010

model age

A003 Frac.1+ recombined

238

U–206Pb4.5727

Amelin et al. 2010

model age

A004 Frac.2 recombined

238

U–206Pb4.6835

Amelin et al. 2010

model age

A004 Frac.3 recombined

238

U– Pb4.716

Amelin et al. 2010

model age

A004 Frac.4 recombined

238

U–206Pb4.5766

Amelin et al. 2010

model age

A004 Frac.5 recombined

238

U– Pb4.6935

Amelin et al. 2010

model age

A005 Frac.6 recombined

238

U–206Pb8.5341

Amelin et al. 2010

model age

A005 Frac.7 recombined

238

U–206Pb4.5683

Amelin et al. 2010

model age

A005 Frac.8 recombined

238

U–206Pb4.6101

Amelin et al. 2010

model age

A005 Frac.9 recombined

238

U–206Pb4.5388

Amelin et al. 2010

model age

aggregate

235

U– Pb4.496

Chen and Tilton 1976

model age

235

U–207Pb5.57

Tatsumoto, Unruh, Desborough 1976

and

whole rock

235

U–207Pb5.03

Tatsumoto, Unruh, Desborough 1976

and

matrix

235U–207Pb

4.99

Tatsumoto, Unruh, Desborough 1976

and

matrix

235U–207Pb

5.02

Tatsumoto, Unruh, Desborough 1976

and

matrix

235U–207Pb

5.36

Tatsumoto, Unruh, Desborough 1976

and

matrix

235U–207Pb

4.79

Tatsumoto, Unruh, Desborough 1976

and

matrix

235U–207Pb

4.45

Tatsumoto, Unruh, Desborough 1976

and

magnetic

235U–207Pb

5.34

Tatsumoto, Unruh, Desborough 1976

and

magnetic

235U–207Pb

5.34

Tatsumoto, Unruh, Desborough 1976

and

magnetic

235U–207Pb

4.68

White

Tatsumoto, Unruh, Desborough 1976

and

aggregate

235U–207Pb

4.67

White

Tatsumoto, Unruh, Desborough 1976

and

aggregate

235U–207Pb

4.88

Pinkish

Tatsumoto, Unruh, Desborough 1976

and

aggregate

235U–207Pb

4.81

Pinkish

Tatsumoto, Unruh, Desborough 1976

and

aggregate A003 1W1

235U–207Pb

4.446

Amelin et al. 2010

model age

A003 1W1 + extra HBr

235U–207Pb

4.450

Amelin et al. 2010

model age

A004 2W1

235U–207Pb

4.709

Amelin et al. 2010

model age

A004 3W1

235U–207Pb

4.218

Amelin et al. 2010

model age

A004 4W1

235U–207Pb

4.404

Amelin et al. 2010

model age

A004 5W1

235U–207Pb

4.580

Amelin et al. 2010

model age

A005 6W1

235U–207Pb

4.434

Amelin et al. 2010

model age

A005 7W1

235U–207Pb

4.389

Amelin et al. 2010

model age

A005 8W1

235U–207Pb

4.503

Amelin et al. 2010

model age

206

206

206

207

White

235

A005 9W1

207

U– Pb

4.415

Amelin 2010

model age model age model age model age model age model age model age model age model age model age model age model age model age

et

al. model age

235

A003 1W2

207 235

A003 1W2 + extra HBr

207 235

A004 2W2

207 235

A004 4W2

207 235

A004 5W2

207 235

A005 6W2

207 235

A005 7W2

207 235

A005 8W2

207 235

A005 9W2

207 235

A004 2W3

207 235

A004 3W3

207 235

A004 4W3

207 235

A004 5W3

207 235

A003 1R Medium–fine “whole rock”

207 235

A003 1R+ (aliquot 2 + extra HBr)

207 235

A004 2R Coarse pyroxene–rich

207 235

A004 3R Coarse melilite and feldspar–rich

207 235

A004 4R Coarse “whole rock”

207 235

A004 5R Medium–fine “whole rock”

207 235

A005 6R Medium–fine dark

207 235

A005 7R Medium–fine light

207 235

A005 8R Fine “whole rock”

207 235

A005 9R Very fine “whole rock”

207 235

A004 2R+W3 recombined

207 235

A004 3R+W3 recombined

207 235

A004 4R+W3 recombined

207 235

A004 5R+W3 recombined

207 235

A003 Frac.1 recombined

207

U– Pb

Amelin 2010

et

4.257

U– Pb

Amelin 2010

et

4.261

U– Pb

Amelin 2010

et

4.310

U– Pb

Amelin 2010

et

4.324

U– Pb

Amelin 2010

et

4.362

U– Pb

Amelin 2010

et

6.131

U– Pb

Amelin 2010

et

4.430

U– Pb

Amelin 2010

et

4.343

U– Pb

Amelin 2010

et

4.398

U– Pb

Amelin 2010

et

4.505

U– Pb

Amelin 2010

et

4.505

U– Pb

Amelin 2010

et

4.490

U– Pb

Amelin 2010

et

4.512

U– Pb

Amelin 2010

et

4.629

U– Pb

Amelin 2010

et

4.629

U– Pb

Amelin 2010

et

4.686

U– Pb

Amelin 2010

et

4.705

U– Pb

Amelin 2010

et

4.685

U– Pb

Amelin 2010

et

4.715

U– Pb

Amelin 2010

et

4.629

U– Pb

Amelin 2010

et

4.634

U– Pb

Amelin 2010

et

4.639

U– Pb

Amelin 2010

et

4.651

U– Pb

Amelin 2010

et

4.638

U– Pb

Amelin 2010

et

4.645

U– Pb

Amelin 2010

et

4.635

U– Pb

Amelin 2010

et

4.649

U– Pb

Amelin 2010

et

4.562

al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age

235

A003 Frac.1+ recombined

207 235

A004 Frac.2 recombined

207 235

A004 Frac.3 recombined

207 235

A004 Frac.4 recombined

207 235

A004 Frac.5 recombined

207 235

A005 Frac.6 recombined

207 235

A005 Frac.7 recombined

207 235

A005 Frac.8 recombined

207 235

A005 Frac.9 recombined

207

U– Pb

Amelin 2010

et

4.563

U– Pb

Amelin 2010

et

4.598

U– Pb

Amelin 2010

et

4.606

U– Pb

Amelin 2010

et

4.563

U– Pb

Amelin 2010

et

4.597

U– Pb

Amelin 2010

et

5.445

U– Pb

Amelin 2010

et

4.564

U– Pb

Amelin 2010

et

4.573

U– Pb

Amelin 2010

et

4.553

al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age al. model age

Discussion In all instances the investigators took extreme care in the preparation of whole-rock samples and the separation of components for subsequent radioisotope analyses. Fusion crusts were removed before crushing whole-rock samples, and often components were then hand picked. If components were separated by density differences in heavy liquids and/or by their magnetic properties, care was always taken to inspect under a microscope the purity of the final products before proceeding with the radioisotope analyses. In whole-rock analyses the complete samples were digested and therefore the components were homogenized in solution before the target radioisotopes were extracted. Whether it was component minerals or constituents such as chondrules or CAIs that were separated, they too were similarly digested and homogenised in solution. In the literature the suitability and integrity for radioisotope analyses of components such as chondrules and CAIs has never been questioned. This is because such components have been found from microscope study to be distinct entities within the overall fabric of meteorites, independent from other components and therefore “self-contained” units suitable for radioisotope analyses on their own. Furthermore, the fairly uniform mineralogical composition of chondrules and CAIs insures that bulk samples of such separated components from individual meteorites will be representative. Therefore, the integrity and quality of the tabulated radioisotope dates has been carefully maintained. The two most obvious observations from a quick glance at Figs. 18–21 are that: In spite of some outlying scattered data, the bulk of the results strongly cluster so that the mode in all four frequency diagrams lies in the range 4.56–4.57 Ga, which would appear to convincingly suggest the Allende CV3 chondrite has an apparent age of between 4.56 and 4.57 Ga. However, this mode disappears entirely if the Pb-Pb ages (and the radioisotope systems calibrated to them) are omitted. The “some outlying scattered data” refers to >90% of the non-Pb-Pb and non-PbPb-calibrated data. Consequently, the only dating method that shows strong clustering is Pb-Pb, and that clustering occurs between 4.56 and 4.57 Ga, although the wide scatter in the results from the other dating methods does seem to roughly group around an apparent age of 4.56 and 4.57 Ga. As already noted the dominant radioisotope system used to obtain this apparent age is Pb-Pb, via both isochron (multisample) and model (single sample) methods. Indeed, if the Pb-Pb and ages calibrated with the Pb-Pb ages are ignored, there is no strong clustering at all.

Fig. 18. Frequency versus radioisotope ages histogram diagram for the isochron ages for some or all components of the Allende CV3 carbonaceous chondrite meteorite, with color coding being used to show the ages obtained by the different radioisotope dating methods. Click image for larger view.

Fig. 19. Frequency versus radioisotope ages histogram diagram for the model ages for chondrules in the Allende CV3 carbonaceous chondrite meteorite, with color coding being used to show the ages obtained by the different radioisotope dating methods. Click image for larger view.

Fig. 20. Frequency versus radioisotope ages histogram diagram for the model ages for Ca-Al inclusions (CAIs) in the Allende CV3 carbonaceous chondrite meteorite, with color coding being used to show the ages obtained by the different radioisotope dating methods. Click image for larger view.

Fig. 21. Frequency versus radioisotope ages histogram diagram for the model ages for whole-rock, matrix and other samples of the Allende CV3 carbonaceous chondrite meteorite, with color coding being used to show the ages obtained by the different radioisotope dating methods. Click image for larger view. Furthermore, a perusal of Tables 1–4 readily reveals that In spite of improvements in the technology and greater sophistication in the techniques to measure the Pb-Pb isotope ratios even more precisely over the decades during which the listed studies were undertaken, there has really been no substantial change in the estimated age for the Allende CV3 chondrite. Indeed, Tatsumoto, Unruh, and Desborough in 1976 determined the first Pb-Pb isochron age of 4.553 ± 0.004 Ga (fig. 16), and yet 34 years later Amelin et al. in 2010 reported the most recently determined Pb-Pb isochron age of 4.56718 ± 0.0002 Ga (fig. 17), a mere difference between these two determinations of only 0.01418 billion years, or 14.18 million years! The Pb-Pb model ages on the Allende whole-rock samples, chondrules, Ca-Al inclusions (CAIs), and its matrix all essentially cluster strongly around the same 4.56–4.57 Ga mark, giving the uniformitarians much certainty that they have successfully and firmly dated the Allende CV3 chondrite as 4.567 Ga old. The same pattern apparent in the Pb-Pb isochron ages is also apparent in the Pb-Pb model ages, namely, that in spite of improvements in the technology and greater sophistication in the techniques to measure the Pb-Pb isotope ratios even more precisely over the decades during which the listed studies were undertaken, there has really been no substantial change in the estimated age for the Allende CV3 chondrite. For example: Huey and Kohman in 1973 obtained a Pb-Pb model age for an Allende whole-rock sample of 4.528 ± 0.04 Ga, yet 37 years later Amelin et al. in 2010 determined a Pb-Pb model age of 4.56755 ± 0.0002 Ga, a mere difference between these two determinations of only 0.03955 billion years, or 39.55 million years! Similarly, Chen and Tilton in 1976 determined Pb-Pb model ages for Allende chondrules of 4.568 Ga and 4.573 Ga, yet 33 years later Connelly and Bizzarro in 2009 obtained Pb-Pb model ages of 4.5659 ± 0.0004 Ga and 4.5666 ± 0.001 Ga, again only meager differences between these determinations of 0.0021 billion years or 2.1 million years and 0.0064 billion years or 6.4 million years respectively! And again, Chen and Tilton in 1976 determined Pb-Pb model ages for Allende Ca-Al inclusions of 4.555 Ga and 4.556 Ga, yet 34 years later Amelin et al. in 2010 obtained Pb-Pb model ages of 4.56664 ± 0.0003 Ga and 4.56702 ± 0.0002 Ga, again only small differences between these determinations of 0.01164 billion years or 11.64 million years and 0.01102 billion years or 11.02 million years respectively! But what of the other radioisotope dating methods? As to be expected, the U-Pb isochron method also yielded similar ages to those obtained by the Pb-Pb isochron method, because both methods involve the radioisotope decay of U to Pb. However, the Rb-Sr and Sm-Nd isochron methods yielded some results within the 4.56–4.57 Ga mode, but also results within 0.3 billion years either side of that mode (fig. 18). Not only are the Rb-Sr isochron ages on either side of the mode of Pb-Pb isochron ages, but so are the model Rb-Sr ages generally in Figs. 19–21. In contrast, the Sm-Nd isochron ages are greater than the Pb-Pb isochron ages (fig. 18). The other “successful” radioisotope methods are not really independent and thus objective, because they are calibrated against the Pb-Pb method (see table 1) and therefore are automatically guaranteed to give ages identical to those obtained by the Pb-Pb isochron method. Specifically, the Al-Mg method is calibrated against the Pb-Pb isochron age for the D’Orbigny achondrite meteorite (Bouvier, Vervoort, and Patchett 2008), the Hf-W method is calibrated against the Pb-Pb isochron age for the St. Marguerite chondrite meteorite (Kleine et al. 2005) and the D’Orbigny achondrite meteorite (Burkhardt et al. 2008), the Mn-Cr method is calibrated against the Pb-Pb isochron age for the St. Marguerite chondrite meteorite (Trinquier et al. 2008), and the D’Orbigny and LEW 86010 achondrite meteorites (Yin et al. 2009), and the I-Xe method is calibrated against the I-Xe age of the Shallowater achondrite meteorite (Hohenberg et al. 2001), which is

calibrated against the Pb-Pb isochron age for the St. Marguerite chondrite meteorite (Brazzle et al. 1999). Thus, as to be expected, all the dates obtained by these methods which are calibrated against these Pb-Pb isochron ages all plot in the 4.56–4.57 Ga mode with the clustered Pb-Pb dates (figs 18 and 20). This strong clustering around the mode of 4.56–4.57 Ga is thus an example of high precision (versus accuracy), with only the Pb-Pb (and calibrated methods) shows precision in ages. So in the eyes of uniformitarians the Pb-Pb isochron dating method stands supreme as the ultimate, most reliable tool for determining the age of the Allende CV3 carbonaceous chondrite meteorite. The same is also true for the model ages obtained for Allende (figs. 19–21 and tables 2–4). Whether it samples, the Pb-Pb model ages have proven to be the most precise, the overwhelming numbers of analyses consistently clustering around the 4.56–4.57 Ga mark. Model ages obtained via the U-Pb, Rb-Sr, and Ar-Ar methods occasionally confirm the Pb-Pb model ages, but they along with the Th-Pb method are also the major contributors to the many scattered model ages among the data. So having established the superior precision of the Pb-Pb radioisotope dating method, now we need to explore whether there are any other patterns in all these isochron and model ages for the Allende CV3 carbonaceous chondrite meteorite that might provide us with clues about the meaning and significance of these isochron and model ages within the creation framework for the history of the earth and the solar system. The major conclusion of the 1997–2005 RATE (radioisotopes and the age of the earth) project was that radioisotope decay rates have not necessarily been constant throughout earth history, because there is evidence that there have been one or more episodes of accelerated rates of radioisotope decay, particularly during the Flood only about 4350 years ago (Vardiman, Snelling, and Chaffin 2005). While there were several lines of documented evidence that confirmed this conclusion, the principal evidence was different isochron ages obtained from the same samples from the same rock units by the different radioisotope dating methods (Snelling 2005; Vardiman, Snelling, and Chaffin 2005). Furthermore, there was a consistent pattern to the isochron ages from the different methods that indicated that there was an underlying systematic cause of these age differences, namely, an episode of accelerated radioisotope decay (Snelling 2005; Vardiman, Snelling, and Chaffin 2005). For example, it was found that the α-decaying radioisotopes U and Sm always gave older ages than the β-decaying K and Rb. And then between the β-decayers, K with the shorter half-life (more rapid decay today) and the lighter atomic weight, always yielded younger ages than the slower decaying and heavier Rb. While exactly the same pattern was not confirmed among the α-decaying U and Sm, both the half-lives and the atomic weights were still believed to be the factors at work. An example will best illustrate how this pattern of different isochron ages obtained from the same samples from the same rock units by the different radioisotope dating methods provides evidence of the proposed accelerated radioisotope decay event. Snelling, Austin, and Hoesch (2003) used the same samples from the Precambrian Bass Rapids diabase sill in the Grand Canyon to obtain isochron dates for this rock unit of 841.5 ± 164 Ma (K-Ar), 1060 ± 24 Ma (Rb-Sr), 1250 ± 130 Ma (Pb-Pb), and 1379 ± 140 Ma (Sm-Nd). Thus it was argued that if all the radioisotope “clocks” were set to zero when the diabase sill crystallized and cooled, then the only way to reconcile these discordant radioisotope dates is if the different parent radioisotopes then decayed over the same real time period from formation of the sill until today at different faster rates than their rates today. It was also suggested that the parent radioisotopes decaying at different accelerated rates was caused by their different atomic weights and abilities to decay (their half-lives) (Snelling, 2005; Vardiman, Snelling, and Chaffin 2005). The mechanism proposed for this past episode of accelerated radioisotope decay was small changes to the binding forces in the nuclei of the parent radioisotopes (Vardiman, Snelling, and Chaffin 2005). These changes would thus have to have affected every atom making up the earth, and by logical extension every atom of the universe at the same time physical laws were created to governing the universe, to operate consistently through time and space. Therefore, we should expect that this past episode of accelerated radioisotope decay had affected the asteroids from where many meteorites have come, and that the meteorites may thus today yield the same pattern of different radioisotope ages from the different radioisotope dating methods. However, looking over Figs. 18–21 again, there appears to be no identical systematic pattern of different radioisotope ages from the different radioisotope dating methods, whether isochron or even model ages. This is more easily seen in Figs. 22 and 23, which are plots of the isochron ages versus the atomic weights and half-lives respectively, based on the data in Table 1 in which the data has been grouped according to the mode of decay of the parent radioisotope. The sole K-Ar isochron age is greater than any of the Rb-Sr isochron ages, and it is also greater than the sole Lu-Hf isochron age, although the latter has a very broad error margin (see table 1). Yet this is the opposite of what should be expected, because K has the shortest half-life today and has the lightest atomic weight among these three β-decayers. At least the sole Lu-Hf isochron age is predictably older than all the Rb-Sr isochron ages, expected because the β-decaying Lu has a longer halflife today and has a heavier atomic weight than Rb. But the Sm-Nd isochron ages are both older and younger than, and similar to, the Pb-Pb and U-Pb isochron ages (figs. 22 and 23). And among all the model ages (tables 2–4) there is so much scatter no discernible systematic pattern is evident. In any case, model ages were not determined and compared during the RATE project, primarily because model ages are dependent on, and thus subject to, the assumptions and deficiencies of the models used to derive them. This is well documented in the literature, and is why model ages generally, apart from Pb-Pb model ages, are regarded as unreliable (Faure and Mensing 2005). Of course, it is premature to draw too firm a conclusion from these observations, because this is just one set of radioisotope ages for one meteorite. More sets of such data from more meteorites are needed, and subsequent papers in preparation will supply these, enabling firmer conclusions to be drawn.

Fig, 22. The isochron age yielded by five radioisotope systems in samples of some or all components from the Allende CV3 carbonaceous chondrite meteorite plotted against the atomic weights of the parent radioisotopes according to their mode of decay. Fig. 23. The isochron ages yielded by five radioisotope systems in samples of some or all components from the Allende CV3 carbonaceous chondrite meteorite plotted against the present half-lives of the parent radioisotopes according to their mode of decay. What is also clear is that even for earthbound rock units there are not yet enough data sets of discordant radioisotope ages derived by different radioisotope dating methods. Those we so far have are primarily for Precambrian rock units, and even for those the pattern of discordance and the amount of discordance are not uniform or the same (Snelling 2005). For example, Austin and Snelling (1998) reported their radioisotope dating study of the Precambrian Cardenas Basalt in the Grand Canyon. The same samples yielded isochron ages of 516 ± 30 Ma (K-Ar), 1111 ± 81 Ma (Rb-Sr) and 1588 ± 170 Ma (SmNd). No Pb-Pb isochron age could be derived from the U-Pb isotopic analytical results. Now while these ages follow the same discordance pattern as those for the Precambrian Bass Rapids diabase sill listed earlier, the amount of discordance is even greater, since the Rb-Sr isochron age is more than twice as large as the KAr isochron age, and the Sm-Nd isochron age is more than three times as large as the K-Ar isochron age. These two Precambrian rock units are about the same 1060–1111 Ma Rb-Sr isochron age, are found in the same Grand Canyon region, and within the creation framework of earth history are generally regarded as pre-Flood. One would have thought that these two Precambrian rock units would have thus both equally suffered from the same accelerated radioisotope decay episode during the Flood year about 4350 years ago, and therefore their radioisotope ages should be discordant by about the same amount.Similarly, the discordance between the isochron ages of 1240 ± 84 Ma (Rb-Sr), 1655 ± 40 Ma (Sm-Nd), and 1883 ± 53 Ma (Pb-Pb) for the Precambrian Brahma amphibolites in the Grand Canyon is different again (Snelling 2005, 2008). Not only is the amount of discordance between the isochron ages different to the discordances between the isochron ages for the other two Grand Canyon Precambrian rock units, but the pattern is also different. For the Bass Rapids diabase sill the Sm-Nd isochron age is older than the Pb-Pb isochron age, whereas for the Brahma amphibolites the Sm-Nd isochron age is younger than the Pb-Pb isochron age. So again, we need many more sets of discordant radioisotope ages data for many more rock units spanning more of the geologic record before any further conclusions can be drawn.However, there is still the issue of why the isochron and model ages for the Allende CV3 carbonaceous chondrite meteorite so definitely cluster around an apparent radioisotope age of 4.56–4.57 Ga, with the current best Pb-Pb isochron and model ages of 4.56718 ± 0.0002 Ga (fig. 17) and 4.56702 ± 0.0002 Ga respectively (Amelin et al. 2010). Of course, it is premature to come to any firm conclusions just based on this set of radioisotope dating data for this one meteorite, but it is nevertheless worthwhile to begin considering possibilities, which can then be discussed in the light of more data sets in future papers. Most meteorites are believed have been derived from asteroids via collisions between them breaking off fragments that then hurtled towards the earth. So to be consistent, if the asteroids were also made on Day Four from this Day One primordial material left over from the making of the planets and their satellites in the solar system, then this would imply the meteorites could represent samples of this same “primordial material.” Similarly, this would have to also mean that at the beginning of Day One the earth was also fashioned out of the same “primordial material.” Thus the 4.56–4.57 Ga Pb isotopic composition

of both this Allende meteorite and the bulk earth (as plotted on the geochron) may represent a geochemical signature from this “primordial material.This raises the obvious question about another aspect of the radioisotope dating technique. The evidence of past accelerated radioisotope decay (non-constant radioisotope decay rates), that is, the inconsistent radioisotope age data in earth rocks (Vardiman, Snelling, and Chaffin 2005), would appear to negate the assumption of constant decay rates that enables the radioisotope “clocks” to be “reading” 4.56–4.57 Ga for the supposed elapsed real time since the formation of the meteorites and the earth. However, another assumption necessary for these radioisotope “clocks” to work is that all the daughter isotopes were only derived by radioisotope decay from the parent isotopes. But what if all the isotopes were created at the beginning in the “primordial material,” including isotopes that subsequently formed by radioisotope decay as daughter isotopes from parent isotopes? In other words, when the “primordial material” was created d was it include in it 206Pb, 207Pb, and 208Pb atoms along with 238U, 235U, and 232Th atoms? It may be reasonable to posit that He did, given that when created the “primordial material” had to have some initial isotopic ratios. Even the conventional scientific community have assumed the initial material of the solar system had the “primeval” Pb isotopic ratios as measured in the troilite (iron sulfide) in the Canyon Diablo iron meteorite (Faure and Mensing 2005). So if He did, then the Pb isotopes we measure today are not all the product of radioisotope decay, and they therefore cannot be measuring the elapsed real time.Following from this is one final consideration. How many atoms of the Pb isotopes were create in the “primordial material”? And if the 4.56–4.57 Ga “age” for this meteorite is a geochemical signature of the “primordial material” were created with some of the Pb isotopes we measure today already in it, then how many of the atoms of the measuredtoday Pb isotopes are due to past accelerated radioisotope decay? Was it most of them, or only some of them? So far we don’t know. What we do know is that here on the earth we don’t find rocks that still have the 4.56–4.57 Ga Pb isotopic signature in them, though most rocks that date back to the continental foundations laid down during Creation Week still contain various large amounts of Pb isotopes in them and therefore yield an array of multi-Ga “ages.” Significantly, the earth sample that plotted on Patterson’s 1956 geochron (fig. 1) was a modern ocean sediment sample whose Pb isotopic signature had been acquired by mixing and integration from many earth rocks over time. This may point to a third possible process responsible for the Pb isotopic compositions in earth rocks, namely, inheritance and mixing in the earth’s mantle and crust subsequent to the creation of the original earth on Day One of the Creation Week, as previously proposed by Snelling (2000, 2005), primarily during the catastrophic geologic processes of the Day Three upheaval when the dry land was formed and during the Flood (Snelling 2009). The resultant conclusion from all these considerations and deliberations, based on the assumptions made, is that the 4.56718 ± 0.0002 Ga “age” for the Allende CV3 carbonaceous chondrite meteorite obtained by Pb-Pb radioisotope isochron dating of one of its Ca-Al inclusions (CAIs) (Amelin et al. 2010) is likely not its true real-time age. The assumptions on which the radioisotope dating methods are based are simply unprovable, and in the light of the evidence for possible past accelerated radioisotope decay in earth rocks and the possibility of an inherited primordial geochemical signature, these assumptions are unreasonable. However, we are still left without a coherent explanation of what these radioisotope compositions really mean within our young-age Creation-Flood framework for earth and universe history. We have some possible clues already, and a clearer picture may yet emerge from continued investigations now in progress, for example, of the radioisotope dating of many other meteorites. Conclusions There is no doubt that after decades of numerous careful radioisotope dating investigations of the Allende CV3 carbonaceous chondrite meteorite that its Pb-Pb isochron age of 4.56718 ± 0.0002 Ga has been well established. This date for Allende is supported by a very strong clustering of other Pb-Pb isochron and model ages in the 4.56–4.57 Ga range, as well as being confirmed by Pb-Pb model ages and by both isochron and model age results by the U-Pb, and to a lesser extent, the Rb-Sr and Sm-Nd methods. The Al-Mg, Hf-W, Mn-Cr, and I-Xe methods are all calibrated against the Pb-Pb isochron method, so their results are not objectively independent. Thus the Pb-Pb isochron dating method stands supreme as the ultimate, most precise tool for determining the age of the Allende CV3 carbonaceous chondrite meteorite. There is no other discernible systematic pattern in the isochron and model ages for Allende, apart from scatter of the U-Pb, Th-Pb, Rb-Sr, and Ar-Ar model ages particularly. The Allende ages do not follow the systematic pattern found in Grand Canyon Precambrian rock units during the RATE project, where the β-decay ages are younger than the α-decay ages according to the lengths of the half-lives and the atomic weights of the parent radioisotopes. Thus there appears to be no evidence in the Allende CV3 carbonaceous chondrite meteorite similar to the evidence found in earth rocks of past accelerated radioisotope decay. Any explanation for the 4.56718 ± 0.0002 Ga age for this Allende meteorite needs to consider the origin of meteorites. Most meteorites appear to be fragments derived from asteroids via collisions, but even in the naturalistic paradigm the asteroids, and thus the meteorites, are regarded as primordial material left over from the formation of the solar system. If some of the daughter isotopes were “inherited” by the Allende meteorite when it was formed from that primordial material, and the parent isotopes in the meteorite were also subject to subsequent accelerated radioisotope decay, then the 4.56718 ± 0.0002 Ga Pb-Pb isochron “age” for the Allende CV3 carbonaceous chondrite meteorite cannot be its true real-time age, which according to the creation paradigm is only about 6000 real-time years. However, these conclusions and the suggested explanation can at best be regarded as tentative and interim while their confirmation or adjustment awaits the examination of more radioisotope dating data from many more meteorites. Such studies are already in progress. Radioisotope Dating of Meteorites II: The Ordinary and Enstatite Chondrites by Dr. Andrew A. Snelling on August 20, 2014 Abstract Meteorites date the earth with a 4.55 ± 0.07 Ga Pb-Pb isochron called the geochron. They appear to consistently yield 4.554.57 Ga radioisotope ages, adding to the uniformitarians’ confidence in the radioisotope dating methods. About 82% of all meteorite falls are chondrites, stony meteorites containing chondrules. Nearly 94% of chondrites are ordinary (O) chondrites, which are subdivided into H, L, and LL chondrites based on their iron contents. Enstatite (E) chondrites comprise only 1.4% of the chondrites. Many radioisotope dating studies in the last 45 years have used the K-Ar, Ar-Ar, RbSr, Sm-Nd, U-Th-Pb, Re-Os, U-Th/He, Mn-Cr, Hf-W, and I-Xe methods to yield an abundance of isochron and model ages for these meteorites from whole-rock samples, and mineral and other fractions. Such age data for fifteen O and E chondrites were tabulated and plotted on frequency versus age histogram diagrams. They generally cluster, strongly in some of these chondrites, at 4.55–4.57 Ga, dominated by Pb-Pb and U-Pb isochron and model ages, testimony to that technique’s supremacy as the uniformitarians’ ultimate, most reliable dating tool. These ages are confirmed by Ar-Ar, Rb-Sr, Re-Os, and Sm-Nd isochron ages, but there is also scatter of the U-Pb, Th-Pb, Rb-Sr, and Ar-Ar model ages, in some cases possibly due to thermal disturbance. No pattern was found in these meteorites’ isochron ages similar to the systematic patterns of isochron ages found in Precambrian rock units during the RATE project, so there is no evidence of past accelerated

radioisotope decay having occurred in these chondrites. This is not as expected, because if accelerated radioisotope decay did occur on the earth, then it could be argued every atom in the universe would be similarly affected at the same time. Otherwise, asteroids and the meteorites derived from them are regarded as “primordial material” left over from the formation of the solar system, which .Doday’s measured radioisotope compositions of these O and E chondrites may reflect a geochemical signature of that “primordial material,” which included atoms of all elemental isotopes. So if some of the daughter isotopes were already in these O and E chondrites when they were formed, then the 4.55-4.57 Ga “ages” for the Richardton (H5), St. Marguerite (H4), Bardwell (L5), Bjurbole (L4), and St. Séverin (LL6) ordinary chondrite meteorites obtained by Pb-Pb and U-Pb isochron and model age dating are likely not their true real-time ages, which according to the creation paradigm is only about 6,000 real-time years. The results of further studies of more radioisotope ages data for many more other meteorites should further elucidate these interim suggestions. Keywords: meteorites, classification, ordinary (O) chondrites, H chondrites, L and LL chondrites, enstatite (E) chondrites, radioisotope dating, Allegan, Forest Vale, Guarena, Richardton, St. Marguerite, Barwell, Bjurbole, Bruderheim, Olivenza, St. Séverin, Abee, Hvittis, Indarch, St. Marks, St. Sauveur, K-Ar, Ar-Ar, Rb-Sr, Sm-Nd, U-Th-Pb, U-Th/He, Re-Os, Mn-Cr, Hf-W, I-Xe, isochron ages, model ages, discordant radioisotope ages, accelerated radioactive decay, asteroids, “primordial material,” geochemical signature, inheritance and mixing Introduction Ever since 1956 when Claire Patterson at the California Institute of Technology in Pasadena reported a Pb-Pb isochron age of 4.55 ± 0.07 Ga for three stony and two iron meteorites, this has been declared the age of the earth (Patterson 1956). Furthermore, many meteorites appear to have consistently dated around the same “age” (Dalrymple 1991, 2004), bolstering the evolutionary community’s confidence that they have successfully dated the age of the earth and the solar system at around 4.57 Ga. It has also strengthened their case for the supposed reliability of the increasingly sophisticated radioisotope dating methods.Creationists have commented little on the radioisotope dating of meteorites, apart from acknowledging the use of Patterson’s geochron to establish the age of the earth, and that many meteorites give a similar old age. Morris (2007) did focus on the Allende carbonaceous chondrite as an example of a well-studied meteorite analysed by many radioisotope dating methods, but he only discussed the radioisotope dating results from one, older (1976) paper. Furthermore, he only focused on the U-Th-Pb model ages published in that paper, apparently ignoring the excellent Pb-Pb isochron age of 4.553 ± 0.004 Ga based on some twenty isotopic analyses of the matrix, magnetic separates, aggregates and chondrules reported in that same paper, as well as the U-Pb concordia isochron age of 4.548 ± 0.025 Ga based on those same samples. In order to rectify this lack of engagement by the creationist community with the meteorite radioisotope dating data, Snelling (2014) obtained as much radioisotope dating data as possible for the Allende CV3 carbonaceous chondrite meteorite (due to its claimed status as the most studied meteorite), displayed the data, and attempted to analyse it. He found that both isochron and model ages for the total rock, separated components, or combinations of these strongly clustered around a Pb-Pb age of 4.56–4.57 Ga. However, while he then sought to discuss the possible significance of this clustering in terms of various potential creationist models for the history of radioisotopes and their decay, drawing firm conclusions from the radioisotope dating data for just this one meteorite was premature. This present contribution is therefore designed to document the radioisotope dating data for more meteorites, the ordinary and enstatite chondrites, so as to continue the discussion of the significance of these data. The Classification of Meteorites Meteorites have been classified into distinct groups and subgroups that show similar chemical, isotopic, mineral, and physical relationships. Within the evolutionary community the ultimate goal of such a classification scheme is to group all known specimens that apparently share a common origin on a single, identifiable parent body, or even a body yet to be identified. This could be another planet, moon, asteroid, or other current solar system object, or one that is believed to have existed in the past (for example, a shattered asteroid). However, several meteorite groups classified this way appear to have come from a single, heterogeneous parent body, or even a single group may contain members that may have come from a variety of similar but distinct parent bodies. So any meteorite classification system is not absolute, and is only as valid as the criteria used to develop it.More than 24,000 meteorites are currently catalogued (Norton 2002), and this number is rapidly growing due to the ongoing discovery of large concentrations of meteorites in the world’s cold and hot deserts (for example, in Antarctica, and Australia and Africa, respectively). Traditionally meteorites have been divided into three overall categories based on whether they are dominantly composed of rocky materials (stones or stony meteorites), metallic material (irons or iron meteorites), or mixtures (stony-irons or stony-iron meteorites). These categories have been in use since at least the early nineteenth century, but they are merely descriptive and do not have any genetic connotations. In reality, the term “stony-iron” is a misnomer, as the meteorites in one group (the CB chondrites) have over 50% metal by volume and were called stony-irons until their affinities with chondrites were recognized. Similarly, some iron meteorites also contain many silicate inclusions but are rarely described as stony-irons.Nevertheless, these three categories are still part of the most widely used meteorite classification system. Stony meteorites are traditionally divided into two other categories—chondrites (meteorites that are characterized by containing chondrules and which apparently have undergone little change since their parent bodies originally formed), and achondrites (meteorites that appear to have had a complex origin involving asteroidal or planetary differentiation). Iron meteorites were traditionally divided into objects with similar internal structures (octahedrites, hexahedrites, and ataxites), but these terms are now only used for descriptive purposes and have given way to chemical group names. Stony-iron meteorites have always been divided into pallasites (which now comprise several distinct groups) and mesosiderites (a textural term which is also synonymous with the name of a modern group).Based on their bulk compositions and textures, meteorites have been more recently divided by Krot et al. (2005) into two major categories—chondrites and non-chondritic meteorites. They also further subdivided the non-chondritic meteorites into the primitive achondrites and igneously differentiated meteorites, the latter including the achondrites, stony-irons (pallasites and mesosiderites), and the irons. Within all these categories the meteorites are grouped on the basis of their oxygen isotopes, chemistry, mineralogy, and petrography.Weisberg, McCoy and Krot (2006) made only minor changes to this classification scheme, which is illustrated in Fig. 1. Note that the three main categories have now been reduced just to chondrites, primitive achondrites and achondrites, the main change being to simply rename the igneously differentiated meteorites the achondrites. As in Krot et al.’s (2005) classification scheme, the IAB and IIICD irons are included in the primitive achondrites because of their silicate inclusions, while the rest of the groups of irons, the stony-irons, the martian and lunar meteorites are included with the other achondrite groups in the achondrites. The Chondrites About 82% of all meteorite falls are chondrites (Norton 2002). As already noted, the chondrites derive their name from their interior texture, which is unlike any found in terrestrial rocks. Dispersed more or less uniformly throughout these meteorites are spherical, sub-spherical and sometimes ellipsoidal structures called chondrules. These range in size from about 0.1 to 4 mm (0,0039 to 0,15 in) diameter, with a few reaching centimeter size. Their abundance within a given chondrite can vary enormously from only a few per cent of the total volume of the meteorite to as much as 70%, with fine-grained matrix

material dispersed between the chondrules. Most chondrules are rich in the silicate minerals olivine and pyroxene. The other major components of chondrites are refractory inclusions—Ca-Al-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs)—and Fe-Ni metal alloys and sulfides (Brearley and Jones 1998; Scott and Krot 2005; Snelling 2014). The chondrites have been subdivided into three classes—carbonaceous (C), ordinary (O), and enstatite (E) chondrites—and fifteen groups, including the rare R and K chondrites (fig. 1). The carbonaceous (C) chondrites, representing almost 4% of all chondrites, are so named because their matrix is carbon-rich, containing various amounts of carbon in the form of carbonates and complex organic compounds including amino acids (Cronin, Pizzarello, and Cruikshank 1988). Further classification involves typing according to where the first meteorite or prototype in the category was found and whose characteristics are used to define the group—for example, CI where I denotes Ivuna, a town in Tanzania, CM where M stands for Mighei in Ukraine, CV where V designates Vigarano in Italy, CO where the O stands for the town of Ornans in France, CR where R denotes Renazzo in Italy, and CK where K designates Karoonda, a town in South Australia (Krot et al. 2009; Norton 2002).

Fig. 1. The classification system for meteorites (after Weisberg, McCoy, and Krot 2006). Click image for larger view. Ordinary (O) chondrites are by far the most common type of meteorite to fall to earth. About 77% of all meteorites and nearly 94% of chondrites are ordinary chondrites. They have been divided into three groups—H, L and LL chondrites—the letters designating their different bulk iron contents and different amounts of metal (Krot et al. 2005; Norton 2002): H chondrites have High total iron contents and high metallic Fe (15–20% Fe-Ni alloys by mass) and smaller chondrules than L and LL chondrites. About 42% of ordinary chondrite falls belong to this group. L chondrites have Low total iron contents (including 7–11% Fe-Ni alloys by mass). About 46% of ordinary chondrite falls belong to this group, which makes them the most common type of meteorite to fall to earth. LL chondrites have Low total iron and Low metal contents (3–5% Fe-Ni alloys by mass, of which 2% is metallic Fe). About 10–12% of ordinary chondrite falls belong to this group. Fig. 2. Two histograms showing the Mg/Si and Ca/Si compositions of chondrites (after Norton 2002; Von Michaelis, Ahrens, and Willis 1969; Van Schmus and Hayes 1974). These atomic ratios differ significantly so that three divisions or classes of chondrites are evident—the enstatite (E) chondrites, ordinary (O) chondrites, and carbonaceous (C) chondrites. The data even allows each class to be resolved into groups—enstatite chondrites into EH and EL; ordinary chondrites into H, L, and LL; and carbonaceous chondrites into CI, CM, CV, and CO. Fig. 3. Plot of the weight percent oxidized iron (in minerals) versus the weight percent iron metal plus FeS (unoxidized iron) in chondrites observed to fall and recovered shortly

thereafter (after Mason 1962). A clear division of the three classes of chondrites is obvious, along with the three groups in the ordinary chondrites—H, L, and LL. Fig. 4. Plot of the fayalite (Fa) content of olivine versus the ferrosilite (Fs) content of orthopyroxene in equilibrated ordinary chondrites clearly reveals the existence of the three oxidation groups—H, L, and LL (after Keil and Fredriksson 1964; Norton 2002).The E chondrites comprise only 1.4% of the chondrites, and are obviously named after their primary silicate mineral, enstatite. Enstatite is the Mg-rich end member of the orthopyroxene solid-solution series and makes up 60–80 vol. % of these meteorites (Krot et al. 2009; Norton 2002). E chondrites contain more metal phases than any other stony meteorite class, with total iron contents varying between 22 and 33 wt %. Virtually all of their iron is in metal phases (13–28 vol. %) or as sulfides (5–17 vol. %). So like the ordinary (O) chondrites, the E chondrites are divided into two groups, EH and EL, according to whether they have relatively High or Low total iron and metal contents. EH chondrites average about 30 vol. % total iron of which about 5 vol. % is sulfides, whereas EL chondrites have about 25 vol. % total iron with 3.5 vol. % sulfides.Of all the meteorites, the chondrites show the greatest similarities in composition, so there are only subtle chemical differences between them. The lithophile elements (those with a strong affinity for oxygen that tend to concentrate in silicate phases) Mg and Ca show the most distinct divisions among the chondrites. Fig. 2 provides histogram plots of Mg/Si and Ca/Si abundances in the chondrite groups (Von Michaelis, Ahrens, and Willis 1969; Van Schmus and Hayes 1974), and shows an obvious distinction between the chondrite groups. The E chondrites exhibit the lowest element/Si ratios, while the C chondrites cluster among the highest ratios, and the ordinary chondrites fall in a tight cluster between the two.An even more striking distinction among the chondrites is evident when oxidized Fe is plotted against Fe in the metal phase and FeS (Mason 1962). Fig. 3 shows a clear distinction between the three classes of chondrites. The E chondrites form a tight cluster exhibiting little oxidation, while the C chondrites display the greatest oxidation of their Fe. Again, the O chondrites fall in between, with separate clusters for each of their constituent H, L and LL groups reflecting their respective Fe metal contents, the H chondrites having the highest Fe metal content.The O chondrites can thus also be classified according to their range of FeO/(FeO + MgO) molecular percentages in their two most common ferromagnesian minerals, olivine and pyroxene. For meteorites in general the fayalite (Fe2SiO4) composition of olivine most commonly lies between 15 and 30% (Fa15-30), with the olivine in a typical O chondrite in the H group having an Fa 18 composition. Like olivine, the orthopyroxene composition in meteorites is measured as the mole percent of the Fe-bearing end member, ferrosilite (FeSiO 3). A typical pyroxene composition for an L group O chondrite would be Fs 22.The enstatite and three groups of ordinary chondrites are distinguished by their total iron content, both oxidized iron (combined in minerals) and metal (unoxidized iron), with the normal variations found in the metal phase, total iron, fayalite (in olivine) and ferrosilite (in pyroxene) contents listed in Table 1. The H, L, and LL designations are as defined above, and are applied to both the O and E chondrites. From these data in Table 1 it is evident that the more oxidized iron in minerals such as fayalite and ferrosilite, the less unoxidized iron there is as metal in the bulk composition of these chondrite meteorites. Furthermore, as the oxidized iron increases in minerals so their oxygen content also increases. So if the mole percent fayalite (Fa) in the olivine and the mole percent ferrosilite (Fs) in the pyroxene are plotted against each other the three ordinary chondrite groups are clearly distinguished, because the H chondrites are the least oxidized and the LL chondrites are the most oxidized of the ordinary chondrites (fig. 4).The classification of chondrites based on chemical and mineralogical criteria is considered a primary classification because the bulk chemistry of meteorites is a primary characteristic. However, meteorites within a particular chemical group, such as the three groups within the ordinary (O) chondrite class, have remarkably similar bulk compositions, but under a hand lens and microscope there are striking petrographic differences. Thus a classification system needs to take into account these petrographic differences so that meteorites can be at least roughly classified by visual inspection. This requires secondary properties be considered, that is, properties that formed from processes which modified the original primary petrographic characteristics. Consequently, an effective classification of chondrites takes into account both their petrographic properties and their chemical differences, using the petrographic differences to subdivide and further refine the chemical groups. Table 1. The classification of the enstatite (E) chondrites (H, L) and ordinary (O) chondrites (H, L, LL) according to their total iron content (after Norton 2002).The symbols H, L, and LL designate the chemical abundance of iron found in each, both as metal (unoxidized) and iron combined in minerals (oxidized)—H (High total iron), L (Low total iron), and LL (Low total iron and Low iron). The fayalite content of olivine and the ferrosilite content of pyroxene are both distinguishing indicators of each group. Fig. 5 is a comprehensive classification chart Metal Total IronFayalite Ferrosilite giving ten criteria proposed by Van Schmus and Class Group (wt %) (wt %) (Fa mole %) (Fs mole %) Wood (1967) that with some modification is still being used to determine the petrographic type Enstatite EH & EL 17–23 22–33 1 0 of each chondrite group. Of the ten, most H 15–19 25–30 16–20 14–20 involve precise chemical and mineral analyses. However, fortunately, among the criteria L 1–10 20–23 21–25 20–30 (numbers 3, 4, 7, and 8) there are well-defined properties that are readily observable through Ordinary LL 1–3 19–22 26–32 32–40 microscope study of thin sections so that the petrographic type can be visually estimated with some confidence without chemical analyses. Criteria numbers 7 and 8 are discussed here because they establish the features needed to understand the classification of the petrographic types to which the remaining criteria refer.

Fig. 5. Chart showing the criteria for distinguishing petrographic types in chondrites (after Brearley and Jones 1998; Norton 2002; Sears and Dodd 1988; Van Schmus and Wood 1967). The ten criteria used in this scheme as they were originally devised are displayed with the details that define each type for each criterion. The broken lines are intended to reflect the lack of sharpness of the boundaries between two petrographic types. Of the ten criteria, the chondrule texture and density (criterion number 7) is the most easily observed. Petrographic types range from 1 to 6. In Type 1 chondrites chondrules are absent. Type 2 chondrites contain distinct chondrules but they are sparsely distributed within a matrix that constitutes nearly 50% of the meteorite by volume. Types 3–6 show progressive stages of thermal metamorphism. The chondrule boundaries became progressively indistinct as solid state recrystallization occurred. This caused alteration of the original chondrule boundaries due to intergrowth of chondrules and the matrix. This recrystallization does not represent heating to the point of fusion, but only sufficient heating to allow migration and recombination of the mineral elements into new minerals. This solid state recrystallization occurred between 400 and 950°C. Ordinary chondrites show petrographic types from 3 to 6 (fig. 5). Often Types 5 and 6 O chondrites show brecciated textures, composed of light clasts set against a dark matrix. It is not unusual to see more than one petrographic type in these breccias. Typically the clasts show Type 5 or 6, while the matrix shows Type 3 or 4. In that case the entire petrographic range is designated Type 3–6. Matrix texture (criterion number 8) is easily observed in thin sections. Matrix textures in Type 1 and 2 chondrites are opaque (black) and very fine-grained with scattered recognizable crystal fragments. Type 2 chondrites show small chondrules, enclosing only about 12% of the meteorites by volume. Type 3 chondrites are still unequilibrated and their matrix is still dark but chondrules are increased in number and take up 30% or more of the volume. From Type 4 to 6, increasing thermal metamorphism in ordinary chondrites produced recrystallization of the matrix in which the crystals grew from cryptocrystalline to near naked-eye visibility. This turned the matrix transparent, giving the interior of the chondrite a white appearance. In examining the homogeneity of olivine and pyroxene compositions (criterion number 1) (fig. 5), from the textures of the ordinary chondrites it is assumed they all began in a relatively unmetamorphosed state designated Type 3. The parent chondritic body from which the meteorite came is said to have been chemically unequilibrated; that is, its mineral composition was heterogeneous, showing wide variations in chemical composition within each mineral. In particular, the two most common minerals in chondrites, olivine and pyroxene, show wide variations in their Mg/Fe compositions (table 1 and fig. 4). The minerals in unequilibrated Type 3 O chondrites were therefore not in equilibrium with their surroundings, the iron composition in olivine and orthopyroxene varying from grain to grain by more than 5%. This variation was progressively reduced through Type 4 until it reached nearly a singular composition at Type 5 where both have become more ferrous. All the olivine and orthopyroxene then have similar iron compositions. Types 5 and 6 chondrites are both homogeneous and equilibrated. The other criteria are listed in Fig. 5 and the characteristics for each criterion are provided for each petrographic type. Most are self-evident and require thin section examinations, whereas others require mineral or bulk chemical analyses. The defining of these petrographic types adds to the classification of chondrite meteorites. The known petrographic types for the chondrite groups are summarized in Fig. 6. Thus chemical types H, L, and LL ordinary (O) chondrites can have a petrographic type between 3 and 6, labelled as H3–H6, L3–L6, and LL3–LL6, respectively. Taken together, the carbonaceous (C) chondrites vary from C1–6 and the enstatite (E) chondrites EH and EL 1–6.

Fig. 6. Chart summarizing the grouping of all chondrites into chemical and petrographic types (after Norton 2002). The chemical types are claimed to represent different asteroid parent bodies, while the petrographic types refer to various states of thermal metamorphism or aqueous alteration occurring on or within the parent bodies. The ordinary chondrites show thermal metamorphism, while the carbonaceous chondrites can be divided into those that show aqueous alteration and those that show thermal metamorphism. The blank boxes indicate the combinations that either do not exist or have yet to be found.However, the exceptions are the Type 3 ordinary and carbonaceous chondrites, which have been sub-typed from 3.0 to 3.9 using a different set of criteria. This was found necessary because Type 3 ordinary chondrites appear to have gone through an unusually large range of thermal metamorphism, more so than other types. Among the new criteria are thermoluminesence sensitivity (tendency to emit light or infrared energy upon heating), percent matrix recrystallization, variation of cobalt in the low nickel kamacite, variations of the fayalite in olivine, and the FeO/(FeO + MgO) ratio in the matrix.While these details are all background information, their presentation is necessary for an understanding of the identifications and designations of the meteorites investigated in this study. It is important to establish what the different designations mean so that one can have confidence that within the groupings of the meteorites chosen for comparing their radioisotope dates the meteorites are essentially the same chemically and mineralogically. This hopefully eliminates any differences in radioisotope ages being due to chemical and/or mineralogical differences. The Radioisotope Dating of the Ordinary and Enstatite Chondrites Fig. 7. Hand specimen of the L4 chondrite Bjurbole (after Norton 2002). Its extreme friability makes it subject to crumbling, so that the chondrules (the high relief, ovoid shapes) frequently fall out of the surrounding matrix leaving cavities. The specimen is 5.3 cm (2 in) in the largest dimension. To thoroughly investigate the radioisotope dating of the ordinary (O) and enstatite (E) chondrite meteorites all the relevant literature was searched. The objective was to find chondrites that have been dated by more than one radioisotope method, and a convenient place to start was Dalrymple (1991, 2004), who compiled lists of such data. Ordinary (O) chondrite meteorites that were found to have been dated multiple times by more than one radioisotope method included five H chondrites—Allegan (H5), Forest Vale (H4), Guarena (H6), Richardton (H5), and St. Marguerite (H4); three L chondrites—Bardwell (L5), Bjurbole (L4) (fig. 7), and Bruderheim (L6) (fig. 8); and two LL chondrites—Olivenza (LL5) and St. Séverin (LL6). Five E chondrite meteorites were found to have been dated multiple times by more than one radioisotope method—Abee (EH4), Hvittis (EL6), Indarch (EH4), St. Marks (EH5), and St. Sauveur (EH5). So this study focused on all fifteen of these meteorites. When papers containing radioisotope dating results for these chondrites were found, the reference lists were also scanned to find further relevant papers. In this way a comprehensive set of papers, articles and abstracts on radioisotope dating of these chondrite meteorites was collected. While it cannot be claimed that all the papers, articles and abstracts which have ever been published containing radioisotope dating results for these chondrites have thus been obtained, the cross-checking undertaken between these publications does indicate the data set obtained is very comprehensive. All the radioisotope dating results from these papers, articles and abstracts were then compiled and tabulated. For ease of viewing and comparing the radioisotope dating data, the isochron and model ages for some or all components of each meteorite were tabulated separately—the H chondrites in Tables 2 (isochron ages) and 3 (model ages), the L chondrites (tables 4 and 5 respectively), the LL chondrites (tables 6 and 7 respectively), and the E chondrites (tables 8 and 9 respectively).

Fig. 8. Photomicrograph of a cut surface of the L6 chondrite Bruderheim, which fell in Alberta, Canada, in 1960 (after Norton 2002). The limonite (yellow-brown hydrated iron oxides) staining of the matrix around the included metallic iron-nickel grains demonstrates the effect of chemical weathering after meteorites fall to earth due to the reactions with water and atmospheric oxygen. The horizontal field of view is 35 mm (1.3 in). The data in these tables were then plotted on frequency versus age histogram diagrams, with the same color coding being used to show the ages obtained by the different radioisotope dating methods—the isochron and model ages for some or all components of the H chondrites (figs. 9 and 10 respectively), of the L chondrites (figs. 11 and 12 respectively), of the LL chondrites (figs. 13 and 14 respectively), and of the E chondrites (figs. 15 and 16 respectively).

Fig. 9. Frequency versus radioisotope ages histogram diagram for the isochron ages for some or all components of the H chondrite meteorites (a) Allegan (H5), (b) Forest Vale (H4), (c) Guarena (H6), (d) Richardton (H5), and (e) St. Marguerite (H4), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 10. Frequency versus radioisotope ages histogram diagram for the model ages for some or all components of the H chondrite meteorites (a) Allegan (H5), (b) Forest Vale (H4), (c) Guarena (H6), (d) Richardton (H5), and (e) St. Marguerite (H4), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 11. Frequency versus radioisotope ages histogram diagram for the isochron ages for some or all components of the L chondrite meteorites (a) Bardwell (L5), (b) Bjurbole (L4), and (c) Bruderheim (L6), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 12. Frequency versus radioisotope ages histogram diagram for the model ages for some or all components of the L chondrite meteorites (a) Bardwell (L5), (b) Bjurbole (L4), and (c) Bruderheim (L6), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 13. Frequency versus radioisotope ages histogram diagram for the isochron ages for some or all components of the LL chondrite meteorites (a) Olivenza (LL5) and (b) St. Séverin (LL6), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 14. Frequency versus radioisotope ages histogram diagram for the model ages for some or all components of the LL chondrite meteorites (a) Olivenza (LL5) and (b) St. Séverin (LL6), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 15. Frequency versus radioisotope ages histogram diagram for the isochron ages for some or all components of the E chondrite meteorites (a) Abee (EH4), (b) Hvittis (EL6), (c) Indarch (EH4), (d) St. Marks (EH5), and (e) St. Sauveur (EH5), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view.

Fig. 16. Frequency versus radioisotope ages histogram diagram for the model ages for some or all components of the E chondrite meteorites (a) Abee (EH4), (b) Hvittis (EL6), (c) Indarch (EH4), (d) St. Marks (EH5), and (e) St. Sauveur (EH5), with color coding being used to show the ages obtained by the different radioisotope dating methods. Click images for larger view. Table 2. Isochron ages for some or all components of the H chondrite meteorites Allegan (H5), Forest Vale (H4), Guarena (H6), Richardton (H5) and St. Marguerite (H4), with the details and literature sources. Sample

Method

Reading

Err +/-

Note

Source

Type

206

4.557

0.008

Unruh, Hutchison, andisochron Tatsumoto 1982 age

4.573

0.003

Brazzle et al. 1999

Mn-Cr

4.5613

0.0008

Polnau and Lugmairisochron 2000 age

Mn-Cr

4.5609

0.0008

Polnau and Lugmairisochron 2001 age

4.63

0.16

Sanz and Wasserburgisochron 1969 age

4.56

0.08

Wasserburg, Papanastassiou, Sanz 1969

Rb-Sr

4.46

0.08

Dalrymple 2004

Rb-Sr

4.48

0.08

Minster, Birck, Allègre 1982

Allegan (H5) whole rock samples plotted with five Barwell samples (1 each) from three other chondrite meteorites

Pb-207Pb

feldspar, temperature extractions (800–1800°C) I-Xe

isochron age

Forest Vale (H4)

Guarena (H6) two pyroxene samples plotted with eighteen fractions of the Olivenza chondrite Rb-Sr

Rb-Sr

thirteen fractions plotted—whole meteorite (3), phosphate (1) and density splits (9)

one sample plotted with ten analyses from five other meteorites Sm-Nd

andisochron age isochron age andisochron age

Jacobsen andisochron Wasserburg 1980 age

4.6

Richardton (H5) seven chondrules

Rb-Sr

isochron age

4.39

0.03

Evensen et al 1979

six silicate chondrules combined with phosphates (4) Rb-Sr

4.611

0.11

Rotenberg and Amelinisochron 2002 age

only phosphates (4)

Rb-Sr

2.284

0.88

Rotenberg and Amelinisochron 2002 age

only silicates (6)

Rb-Sr

4.62

0.14

Rotenberg and Amelinisochron 2002 age

chondrules and fragments

Pb-Pb

4.5627

0.0017

Amelin, Ghosh, Rotenberg 2005

andisochron age

phosphate fractions

Pb-Pb

4.5507

0.0026

Amelin, Ghosh, Rotenberg 2005

andisochron age

nine meteorite fragments

207

Pb-206Pb

4.545

0.01

Abranches, Arden, andisochron Gale 1980 age

six mineral fractions

207

Pb-206Pb

4.5622

0.0012

Amelin 2001

204

Pb/206PbPb/206Pb

4.5512

0.0032

phosphates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5505

0.0008

phosphates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.551

0.001

phosphates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5583

0.0077

phosphates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5546

0.0036

phosphates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5507

0.0026

phosphates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5629

0.0016

silicates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5621

0.0042

silicates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206/PbPb/206Pb

4.5626

0.0014

silicates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5627

0.0017

silicates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.5631

0.0007

silicates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/206PbPb/206Pb

4.562

0.0008

silicates

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/238UPb/238U

4.5523

0.0031

Amelin, Ghosh, Rotenberg 2005

andisochron age

Pb/238UPb/238U

4.5624

0.0022

Amelin, Ghosh, Rotenberg 2005

andisochron age

all fractions

207 204

#2 excluded

207 204

radiogenic (206Pb-204Pb > 200)

207 204

all fractions plus troilite

207 204

all fractions plus primordial Pb

207

all fractions plus Göpel, Manhès, and Allègre 1994 analyses

204 207 204

all fractions

207 204

all fractions plus troilite

207 204

all fractions plus primordial Pb

207 204

chondrules

207 204

chondrules plus troilite

207 204

chondrules plus primordial Pb

207 206

phosphates (5)

207 206

isochron age

silicates (8)

207

nine meteorite fragments

U-Pb

4.549

0.007

Abranches, Arden, andisochron Gale 1980 age

five phosphate fractions

U-Pb

4.551

0.0035

Amelin 2000

isochron age

six mineral fractions

U-Pb

4.5623

0.0013

3D linear regression Amelin 2001

isochron age

phosphates (5)

U-Pb

4.5513

0.0029

3D linearAmelin, Ghosh, regression Rotenberg 2005

andisochron age

silicates (8)

U-Pb

4.563

0.001

3D linearAmelin, Ghosh, regression Rotenberg 2005

andisochron age

phosphates (5)

235

U-207Pb

4.538

0.004

Amelin, Ghosh, Rotenberg 2005

andisochron age

silicates (8)

235

U-207Pb

4.562

0.026

Amelin, Ghosh, Rotenberg 2005

andisochron age

phosphates (5)

232

Th-208Pb

4.486

0.14

Amelin, Ghosh, Rotenberg 2005

andisochron age

silicates (8)

232

Th-208Pb

4.594

0.15

Amelin, Ghosh, Rotenberg 2005

andisochron age

four phosphate samples plotted with nine other samples of four other chondrite meteorites Sm-Nd

4.182

0.51

Rotenberg and Amelinisochron 2001 age

twelve chondrules and phosphates plotted with twentytwo other samples with seven other meteorites Sm-Nd

4.588

0.1

Amelin and Rotenbergisochron 2004 age

twelve chondrules and phosphates plotted with seventyseven other samples of other chondrite meteorites Sm-Nd

4.547

0.11

Amelin and Rotenbergisochron 2004 age

five phosphates chondrule fractions

Sm-Nd

4.624

0.12

Amelin and Rotenbergisochron 2004 age

Hf-W

4.5628

0.001

Kleine et al 2008

Mn-Cr

4.5563

0.0016

Polnau and Lugmairisochron 2001 age

4.588

0.002

Brazzle et al. 1999

isochron age

and

seven

eleven fractions whole rock, silicates, chondrite fractions

and

feldspar, temperature extractions (800-1800°C) I-Xe

isochron age

St. Marguerite (H4) whole rock residue—CDT

206

Pb-207Pb

4.5624

0.0011

Bouvier et al 2007

isochron age

chondrule residue—CDT

206

Pb-207Pb

4.5655

0.0012

Bouvier et al 2007

isochron age

206

Pb-207Pb

4.5633

0.0011

Bouvier et al 2007

isochron age

206

Pb-207Pb

4.5643

0.0008

Bouvier et al 2007

isochron age

206

Pb-207Pb

4.5617

0.0012

Bouvier et al 2007

isochron age

207

Pb-204Pb

4.5627

0.0006

Bouvier et al 2007

isochron age

Radioisotope Dating of Meteorites II: The Ordinary and Enstatite Chondrites 267 mean of a whole rock and chondrule ages of Göpel, Manhès, and Allègre (1994) and Bouvier et al (2007) Pb-Pb

4.5644

0.0034

Kleine et al 2008

isochron age

one magnetic and three nonmagnetic fractions Hf-W

4.5653

0.0006

Kleine et al 2002

isochron age

four non-magnetic fractions and the mean of three analyses of a metal fraction Hf-W

4.5669

0.0005

Kleine et al 2008

isochron age

internal isochron recalculated

4.5665

0.0005

Kleine et al 2008

isochron age

whole rock, silicate and chromite fractions Mn-Cr

4.5649

0.0007

Polnau and Lugmairisochron 2001 age

seven fractions of minerals and chondrules Mn-Cr

4.5629

0.001

Trinquier et al 2008

isochron age

phosphate, temperature extractions (800–1800°C) I-Xe

4.565

0.006

Brazzle et al 1999

isochron age

feldspar, temperature extractions (800–1800°C) I-Xe

4.567

0.002

Brazzle et al 1999

isochron age

pyroxene-olivine leachate

residue—

pyroxene-olivine residue—CDT chondrule—pyroxene—olivine residue whole rock, chondrules, phosphates, olivene leachates— ten point plotted

Hf-W

Table 3. Model ages for some or all components of the H chondrite meteorites Allegan (H5), Forest Vale (H4), Guarena (H6), Richardton (H5), and St. Marguerite (H4), with the details and literature sources. Sample

Method

Reading

Err +/-

4.511

Note

Source

Type

0.011

Trieloff et al 2003

plateau age

Allegan (H5) whole rock (with 100%, 24 out of 26 extractions) Ar-Ar fragments of the meteorite

206

Pb-207Pb 4.5477

0.0019

Göpel, Manhès, and Allègre 1994 model age

fragments of the meteorite

206

Pb-207Pb 4.5359

0.0019

Göpel, Manhès, and Allègre 1994 model age

fragments of the meteorite

206

Pb-207Pb 4.5385

0.0015

Göpel, Manhès, and Allègre 1994 model age

phosphate separates

206

Pb-207Pb 4.5502

0.0007

Göpel, Manhès, and Allègre 1994 model age

phosphate separates

206

Pb-207Pb 4.5563

0.0008

Göpel, Manhès, and Allègre 1994 model age

Forest Vale (H4) whole rock (width 40%, 19 out of 42 extractions) Ar-Ar

4.522

0.008

Trieloff et al 2003

whole rock

Ar-Ar

4.52

0.03

Turner, Enright, and Hennessey 1978 plateau age

fragment of meteorite

206

Pb-207Pb 4.6142

0.0042

Göpel, Manhès, and Allègre 1994 model age

phosphate separate

206

Pb-207Pb

0.0007

Göpel, Manhès, and Allègre 1994 model age

plateau age

Guarena (H6) Ar-Ar

4.44

0.03

Turner, Enright, and Hennessey 1978 plateau age

Ar-Ar

4.445

0.008

Trieloff et al 2003

plateau age

feldspar separate (9/14 extractions, 90% Ar) Ar-Ar

4.472

0.013

Trieloff et al 2003

plateau age

pyroxene separate (9/14 extractions, 80% Ar) Ar-Ar

4.46

0.013

Trieloff et al 2003

plateau age

mean of the whole rock, feldspar and pyroxene ages Ar-Ar

4.454

0.006

Trieloff et al 2003

plateau age

4.44

0.06

Dalrymple 2004

plateau age

whole rock (10/24 extractions, 80% Ar)

Ar-Ar two phosphate separates

206

Pb-207Pb 4.5044

0.0005

Göpel, Manhès, and Allègre 1994 model age

two phosphate separates

206

Pb-207Pb 4.5044

0.0005

Göpel, Manhès, and Allègre 1994 model age

two phosphate separates

206

Pb-207Pb 4.5056

0.0005

Göpel, Manhès, and Allègre 1994 model age

fragment of meteorite

206

Pb-207Pb 4.5172

0.0018

Göpel, Manhès, and Allègre 1994 model age

phosphates (5)

235

U-207Pb

4.538

0.004

Amelin, Ghosh, andisochron Rotenberg 2005 age

silicates (8)

235

U-207Pb

4.562

0.026

Amelin, Ghosh, andisochron Rotenberg 2005 age

phosphates (5)

232

Th-208Pb 4.486

0.14

Amelin, Ghosh, andisochron Rotenberg 2005 age

silicates (8)

232

Th-208Pb 4.594

0.15

Amelin, Ghosh, andisochron Rotenberg 2005 age

Richardton (H5) whole rock (width 100%, 32 out of 32 extractions) Ar-Ar

4.595

0.011

Trieloff et al 2003

whole rock

Ar-Ar

4.5

0.03

Turner, Enright, and Hennessey 1978 plateau age

chondrules (6) plus matrix

Rb-Sr

4.5

Evensen et al 1979 model age

chondrules (6) plus matrix

Rb-Sr

4.44

Evensen et al 1979 model age

chondrules (6) plus matrix

Rb-Sr

4.48

Evensen et al 1979 model age

chondrules (6) plus matrix

Rb-Sr

4.59

Evensen et al 1979 model age

chondrules (6) plus matrix

Rb-Sr

4.5

Evensen et al 1979 model age

chondrules (6) plus matrix

Rb-Sr

4.46

Evensen et al 1979 model age

chondrules (6) plus matrix

Rb-Sr

4.8

Evensen et al 1979 model age

plateau age

mean of five phosphate fractions

Pb-Pb

whole rock

207

whole rock

207

Pb- Pb 4.604

whole rock

207

Pb-206Pb 4.478

0.008

Huey and Kohman 1973 model age

whole rock

207

Pb-206Pb 4.519

0.015

Tatsumoto, Knight, and Allègre 1973 model age

phosphates

207

Pb-206Pb 4.5514

0.0006

Göpel, Manhès, and Allègre 1994 model age

phosphates

207

Pb-206Pb 4.5534

0.0006

Göpel, Manhès, and Allègre 1994 model age

plagioclase

207

Pb-206Pb 4.5644

0.0064

Amelin 2001

model age

olivine

207

Pb- Pb 4.5646

0.0037

Amelin 2001

model age

pyroxene

207

Pb-206Pb 4.5621

0.0009

Amelin 2001

model age

pyroxene

207

Pb- Pb 4.5627

0.001

Amelin 2001

model age

pyroxene

207

Pb-206Pb 4.5649

0.0023

Amelin 2001

model age

pyroxene

207

Pb-206Pb 4.5623

0.0007

Amelin 2001

model age

phosphate fractions

207

Pb-206Pb 4.554

0.001

Rotenberg Amelin 2001

and model age

phosphate fractions

207

Pb-206Pb 4.555

0.001

Rotenberg Amelin 2001

and model age

phosphate fractions

207

Pb-206Pb 4.56

0.002

Rotenberg Amelin 2001

and model age

phosphate fractions

207

Pb-206Pb 4.552

0.001

Rotenberg Amelin 2001

and model age

silicate chondrules

207

Pb-206Pb 4.572

0.001

Rotenberg Amelin 2002

and model age

silicate chondrules

207

Pb-206Pb 4.559

0.003

Rotenberg Amelin 2002

and model age

silicate chondrules

207

Pb-206Pb 4.562

0.001

Rotenberg Amelin 2002

and model age

silicate chondrules

207

Pb-206Pb 4.561

0.001

Rotenberg Amelin 2002

and model age

silicate chondrules

207

Pb-206Pb 4.563

0.002

Rotenberg Amelin 2002

and model age

silicate chondrules

207

Pb-206Pb 4.56

0.001

Rotenberg Amelin 2002

and model age

207

Pb-206Pb 4.554

0.0013

Phosphate 1

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5554

0.0007

Phosphate 2

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5531

0.0008

Phosphate 3

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5597

0.0016

Phosphate 4

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5519

0.0007

Phosphate 5

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.4593

0.005

Troilite

Amelin, Ghosh, and Rotenberg 2005 model age

meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973

4.5539

0.0028

Pb-206Pb 4.633 206

206

206

Amelin 2000

model age

Tilton 1973

model age

Tilton 1973

model age

meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Tatsumoto, Knight, and Allègre 1973 meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite meteorite fractions and fragments using primodial Pb of Richardson troilite

207

Pb-206Pb 4.5666

0.0065

Low-density fraction 1

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5638

0.0045

Low-density fraction 2

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5608

0.0261

Olivine

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5621

0.0008

Chondrule fragment 1

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5627

0.0008

Chondrule fragment 2

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5623

0.0007

Chondrule Fragment 3

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5626

0.0007

Chondrule 3

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5613

0.0008

Chondrule 4

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5608

0.001

Chondrule 8

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5608

0.001

Chondrule 8

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5574

0.0014

Phosphate 1

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5581

0.0008

Phosphate 2

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5566

0.0008

Phosphate 3

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5705

0.0018

Phosphate 4

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.553

0.0008

Phosphate 5

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5674

0.0052

Low-density fraction 1

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5674

0.0037

Low-density fraction 2

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5864

0.0249

Olivine

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5629

0.0008

Chondrule fragment 1

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5635

0.0008

Chondrule fragment 2

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5629

0.0007

Chondrule Fragment 3

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5641

0.0007

Chondrule 3

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5623

0.0008

Chondrule 4

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5632

0.0011

Chondrule 8

Amelin, Ghosh, and Rotenberg 2005 model age

fractions, weighted averages, corrected using primodial Pb (all fractions) fractions, weighted averages, corrected using primodial Pb (#2 excluded) fractions, weighted averages, corrected using primodial Pb (radiogenic [206Pb204Pb > 200])

207

Pb-206Pb 4.553

0.0028

phosphates

Amelin, Ghosh, and Rotenberg 2005 model age

207

Pb-206Pb 4.5533

0.0039

phosphates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5535

0.0026

phosphates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5531

0.0023

silicates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5621

0.0005

silicates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.562

0.0007

silicates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5568

0.0053

phosphates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5562

0.0081

phosphates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.556

0.0039

phosphates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.556

0.004

silicates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5632

0.0007

silicates

Amelin, Ghosh, and Rotenberg 2005 model age

207Pb-206Pb

4.5631

0.0028

silicates

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 1

206Pb-238U

4.628

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 2

206Pb-238U

4.596

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 3

206Pb-238U

4.647

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 4

206Pb-238U

4.845

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 5

206Pb-238U

4.548

Amelin, Ghosh, and Rotenberg 2005 model age

Troilite

206Pb-238U

6.473

Amelin, Ghosh, and Rotenberg 2005 model age

Low-density fraction 1

206Pb-238U

5.165

Amelin, Ghosh, and Rotenberg 2005 model age

Low-density fraction 2

206Pb-238U

4.724

Amelin, Ghosh, and Rotenberg 2005 model age

Olivine

206Pb-238U

5.519

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 1

206Pb-238U

4.576

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 2

206Pb-238U

4.593

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule Fragment 3

206Pb-238U

4.554

Amelin, Ghosh, and Rotenberg 2005 model age

fractions, weighted averages, corrected using primodial Pb (all fractions plus Göpel, Manhès, and Allègre 1994 analyses) fractions, weighted averages, corrected using primodial Pb (all fractions) fractions, weighted averages, corrected using primodial Pb (chondrules) fractions, weighted averages, corrected using Richardton troilite Pb (all fractions) fractions, weighted averages, corrected using Richardton troilite Pb (#2 excluded) fractions, weighted averages, corrected using Richardton troilite Pb (radiogenic [206Pb-204Pb >200]) fractions, weighted averages, corrected using Richardton troilite Pb (all fractions plus Göpel, Manhès, and Allègre 1994 analyses) fractions, weighted averages, corrected using Richardton troilite Pb (all fractions) fractions, weighted averages, corrected using Richardton troilite Pb (chondrules)

Chondrule 3

206Pb-238U

4.643

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule 8

206Pb-238U

4.625

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 1

207Pb-235U

4.577

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 2

207Pb-235U

4.568

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 3

207Pb-235U

4.582

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 4

207Pb-235U

4.646

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 5

207Pb-235U

4.551

Amelin, Ghosh, and Rotenberg 2005 model age

Troilite

207Pb-235U

5.013

Amelin, Ghosh, and Rotenberg 2005 model age

Low-density fraction 1

207Pb-235U

4.743

Amelin, Ghosh, and Rotenberg 2005 model age

Low-density fraction 2

207Pb-235U

4.612

Amelin, Ghosh, and Rotenberg 2005 model age

Olivine

207Pb-235U

4.837

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 1

207Pb-235U

4.566

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 2

207Pb-235U

4.572

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule Fragment 3

207Pb-235U

4.56

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule 3

207Pb-235U

4.587

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule 8

207Pb-235U

4.58

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 1

208Pb-232Th

4.607

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 2

208Pb-232Th

4.619

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 3

208Pb-232Th

4.683

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 4

208Pb-232Th

4.98

Amelin, Ghosh, and Rotenberg 2005 model age

Phosphate 5

208Pb-232Th

4.604

Amelin, Ghosh, and Rotenberg 2005 model age

Low-density fraction 1

208Pb-232Th

4.6

Amelin, Ghosh, and Rotenberg 2005 model age

Low-density fraction 2

208Pb-232Th

4.626

Amelin, Ghosh, and Rotenberg 2005 model age

Olivine

208Pb-232Th

5.127

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 1

208Pb-232Th

4.582

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 2

208Pb-232Th

4.57

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule fragment 3

208Pb-232Th

4.565

Amelin, Ghosh, and Rotenberg 2005 model age

Chondrule 3

208Pb-232Th

4.32

Amelin, Ghosh, and Rotenberg 2005 model age

208Pb-232Th

4.249

whole rock (30/38 extractions, 93% Ar)

Ar-Ar

4.532

two phosphate fractions

206

two phosphate fractions

Chondrule 8

Amelin, Ghosh, and Rotenberg 2005 model age

St. Marguerite (H4) 0.016

Trieloff et al 2003

plateau age

Pb-207Pb 4.563

0.0006

Göpel, Manhès, and Allègre 1994 model age

206

Pb-207Pb 4.5627

0.0007

Göpel, Manhès, and Allègre 1994 model age

two phosphate fractions

206

Pb-207Pb 4.5627

0.0006

Göpel, Manhès, and Allègre 1994 model age

fragment of meteorite

206

Pb-207Pb 4.5667

0.0016

Göpel, Manhès, and Allègre 1994 model age

Table 4. Isochron ages for some or all components of the L chondrite meteorites Bardwell (L5), Bjurböle (L4), and Bruderheim (L6), with the details and literature sources. Sample

Method

Reading

Err +/-

Note

Source

Type

isochron age

Barwell (L5) two samples plotted with 16 other points from six other meteorites two whole rocks, chondrules and troilie fractions, plus -150 mesh fraction

207

Pb-206Pb 4.521

0.01

Unruh 1982

207

Pb-206Pb 4.557

0.008

Unruh, Hutchison, Tatsumoto 1982

whole rock and troilite plotted with other L chondrites U-Pb

Unruh 1980

4.55

and

and isochron age

Tatsumoto isochron age

Bjurböle (L4) two silicate fractions with seven other samples of two other L chondrites Rb-Sr

0.054

Rotenberg 2002

and

4.54

Amelin isochron age

silicate (2) and phosphate (3) fractions plotted with silicate (7) and phosphate (4) fractions of two other L chrondrites Rb-Sr

0.04

Rotenberg 2002

and

4.499

Amelin isochron age

two pyroxene fractions

Pb-Pb

4.5542

0.0046

Amelin 2001

pyroxenes

Pb-Pb

4.5543

0.0033

Rotenberg 2001 Unruh 1980

isochron age and

and

Amelin isochron age

triolite sample plotted with seven other L chondrites U-Pb

4.55

Tatsumoto

three phosphate fractions plotted with ten other samples of four other chondrite meteorites Sm-Nd

4.182

0.51

Rotenberg 2001

four chondrules and three phosphates plotted with 27 other samples of seven other chondrite meteorites Sm-Nd

0.1

Amelin 2004

and

4.588

four chondrules and three phosphates plotted with 82 other samples of seven other chondrite meteorites Sm-Nd

0.11

Amelin 2004

and

4.547

whole rock

I-Xe

4.566

0.22

Hohenberg and Kennedy 1981; Brazzle et al. 1999 isochron age

whole rock and fractions (eight total)

Rb-Sr

4.54

15 whole rock samples

207

15 whole rock samples

U-Pb

isochron age and

Amelin isochron age

Rotenberg isochron age Rotenberg isochron age

Bruderheim (L6)

Pb-206Pb 4.482

triolite and whole rock plotted with seven other L-chrondrites U-Pb

4.536

Shima and Honda 1967

isochron age

Gale. Arden, Abranches 1980

and

0.017

isochron age

Gale. Arden, Abranches 1980

and

0.006

Unruh 1980

4.55

and

isochron age

Tatsumoto isochron age

Table 5. Model ages for some or all components of the L chondrite meteorites Bardwell (L5), Bjurböle (L4), and Bruderheim (L6), with the details and literature sources. Sample

Method

Reading

Err +/-

Note

Source

Type

Barwell (L5) Ar-Ar

4.45

0.06

Turner, Enright, and Hennessey 1978 plateau age

Ar-Ar

4.45

0.03

Turner, Enright, and Cardogan, 1979 plateau age Gale, Arden, and Hutchinson 1972 model age

whole rock sample

207

Pb-206Pb 4.68

troilite sample

207

Pb-206Pb 4.548

whole rock sample

207

Pb-206Pb 4.561

207

Pb-206Pb 4.549

0.004

Unruh 1982

model age

207

Pb-206Pb 4.545

0.003

Unruh 1982

model age

207

Pb-206Pb 4.56

0.005

Unruh 1982

model age

207

Pb-206Pb 4.56

0.005

meteorite fragments

207

Pb-206Pb 4.5577

0.0018

Göpel, Manhès, and Allègre 1994 model age

meteorite fragments

207

Pb-206Pb 4.5522

0.001

Göpel, Manhès, and Allègre 1994 model age

phosphate separates

207

Pb-206Pb 4.5382

0.0007

Göpel, Manhès, and Allègre 1994 model age

phosphate separates

207

Pb-206Pb 4.5384

0.0008

Göpel, Manhès, and Allègre 1994 model age

207

Pb-208Pb 4.583

0.025

Unruh 1982

model age

207

Pb-208Pb 4.578

0.025

Unruh 1982

model age

silicate fractions of two whole rock samples silicate fractions of two whole rock samples “contaminant-corrected” concordant model ages for two silicate fractions of whole-rock samples

silicate fractions of two whole rock samples “contaminant-corrected” concordant model ages for two silicate fractions of whole rock samples

Unruh and Tatsumoto 1980 model age

0.004

Unruh and Tatsumoto 1980 model age

model age

two samples plotted with 16 other points from six other meteorites U-Pb

4.547

0.015

Unruh 1982

concordia age

triolite-corrected data for two samples plotted with 16 other data points from six other meteorites U-Pb

4.551

0.007

Unruh 1982

concordia age

U-Pb

4.564

0.005

Unruh 1982

concordia age

whole rock

K-Ar

4.32

K-Ar

4.394

0.016

Podosek and Hunekestep 630°C extraction 1973b age

model

whole rock

K-Ar

4.369

0.005

Podesek and Hunekestep 745°C extraction 1973b age

model

whole rock

K-Ar

4.413

0.009

Podosek & Hunekestep 850°C extraction 1973b age

model

whole rock

K-Ar

4.438

0.015

Podesek and Hunekestep 935°C extraction 1973b age

model

whole rock

K-Ar

4.334

0.029

1040°C extraction

Podosek and Hunekestep 1973b age

model

whole rock

K-Ar

4.518

0.005

1125°C extraction

Podesek and Hunekestep 1973b age

model

whole rock

K-Ar

4.496

0.004

1195°C extraction

Podosek and Hunekestep 1973b age

model

whole rock

Bjurböle (L4) Geiss and Hess 1958; Wood 1967 model age

K-Ar

4.486

0.002

1370°C extraction

Podesek and Hunekestep 1973b age

model

whole rock

K-Ar

4.513

0.005

1515°C extraction

Podesek and Hunekestep 1973b age

model

whole rock whole rock

K-Ar

4.51

high temperature

Podesek and Huneke 1973b plateau age

whole rock

Ar-Ar

4.51

triolite

207

Pb-206Pb 4.556

whole rock

207

Pb-206Pb 4.583

whole rock

207

Pb-206Pb 4.59

0.006

Unruh 1982

207

Pb-206Pb 4.5543

0.0033

Rotenberg Amelin 2001

and model age

silicate fractions

207

Pb-206Pb 4.556

0.004

Rotenberg Amelin 2001

and model age

silicate fractions

207

Pb-206Pb 4.552

0.003

Rotenberg Amelin 2001

and model age

phosphate fractions

207

Pb-206Pb 4.59

0.011

Rotenberg Amelin 2001

and model age

phosphate fractions

207

Pb-206Pb 4.661

0.011

Rotenberg & Amelin 2001 model age

phosphate fractions

207

Pb-206Pb 4.519

0.002

Rotenberg & Amelin 2001 model age

pyroxene

207

Pb-206Pb 4.5545

0.0012

Amelin 2001

model age

pyroxene

207

Pb-206Pb 4.5546

0.0018

Amelin 2001

model age

whole rock

U-Th/He

0.08

Turner 1969

plateau age

0.01

Unruh and Tatsumoto 1980 model age Unruh and Tatsumoto 1980 model age model age

Eberhardt and Hess 1960; Wood 1967 model age

4.2

Bruderheim (L6) whole rock

207

Pb-206Pb 4.53

whole rock

207

Pb-206Pb 4.518

whole rock sample

207

Pb- Pb 4.605

triolite

207

Pb-206Pb 4.537

whole rock

207

Pb-206Pb 4.55

whole rock

207

Pb-206Pb 4.535

whole rock sample

206

Pb-238U

whole rock sample

206

whole rock sample

Gale, Arden, and Hutchinson 1972 model age Huey 1973

0.003

206

and

Tilton 1973

Kohman model age model age

Unruh and Tatsumoto 1980 model age

0.004

Unruh and Tatsumoto 1980 model age Unruh 1982

model age

4.126

Tilton 1973

model age

Pb-238U

4.542

Tilton 1973

model age

206

Pb-238U

4.959

Tilton 1973

model age

whole rock sample

207

Pb-235U

4.447

Tilton 1973

model age

whole rock sample

207

Pb- U

4.592

Tilton 1973

model age

whole rock sample

207

Pb-235U

4.703

Tilton 1973

model age

235

0.004

Table 6. Isochron ages for some or all components of the LL chondrite meteorites Olivenza (LL5) and St. Séverin (LL6), with the details and literature sources. Sample

Method

Reading

Err +/-

4.63

0.16

Note

Source

Type

Olivenza (LL5) 18 fractions—whole rock, chondrules, pyroxene, olivene, density splits and leachates Rb-Sr

Sanz and Wasserburg 1969 isochron age

Rb-Sr

4.53

0.16

Dalrymple 1991

isochron age

4.486

0.02

Minster and Allègre 1981

isochron age

Rb-Sr

4.56

0.15

These four on isochron Gopalan and Wetherill 1969 isochron age

whole rock + heavy liquid separates + whitlockite Rb-Sr

4.61

0.15

Manhès, Minster, and Allègre 1978 isochron age

two whole rock samples with ten other meteorites Rb-Sr

4.486

0.02

Minster and Allègre 1981

isochron age

recalculated

Rb-Sr

4.51

0.15

Minster and Allègre 1981

isochron age

one sample plotted with five iron meteorites Re-Os

4.58

0.21

Luck, Birck, and Allègre 1980isochron age

one sample plotted with 21 other meteorites Re-Os

4.55

five whole rock, two metal, one FeS analyses Re-Os

4.68

0.15

Chen, Papanastassiou, and Wasserburg 1998 isochron age

whole rock, px + ol, ap + met, 3 leachates Pb-Pb

4.5759

0.009

Bouvier et al 2007

isochron age

phosphates

Pb-Pb

4.5549

0.0002

Bouvier et al 2007

isochron age

whole rock + plagioclase + whitlockite

206

Pb-207Pb 4.543

0.019

Manhès, Minster, and Allègre 1978 isochron age

208

Pb-206Pb 4.55

207

Pb-204Pb 4.558

one whole rock plotted with ten other meteorites Rb-Sr St. Séverin (LL6) four fractions meteorites

ploted

with

other

whole rock + plagioclase + Canyon Diablo triolite phosphates (Manhès, Minster, and Allègre1978; Chen and Wasserburg 1981; Göpel, Manhès, and Allègre 1994)

Luck and Allègre 1983

isochron age

Manhès, Minster, and Allègre 1978 isochron age

0.006

Tera and Carlson 1999

isochron age

whole rock, whitlockite, light and dark fractions Sm-Nd

4.55

0.33

Jacobson and Wasserburg 1984 isochron age

whole rock, silicates, and chromitespinel fractions Mn-Cr

4.5546

0.0014

Glavin and Lugmair 2003

isochron age

feldspar, temperature extractions (800– 1800°C) I-Xe

4.558

0.004

Brazzle et al 1999

isochron age

Table 7. Model ages for some or all components of the LL chondrite meteorites Olivenza (LL5) and St. Séverin (LL6), with the details and literature sources. Sample

Method

Reading

Err +/-

Note

Source

Type

Ar-Ar

4.49

0.06

Turner, Enright, and Hennessey 1978 plateau age

one sample

K-Ar

4.38

0.06

Funkhouser, Kirsten, and Schaeffer 1967 model age

whole rock sample

K-Ar

4.6

0.05

used Ar-Ar measurements

Podosek 1971

14 samples from drill core K-Ar

4.4

0.45

used Ar-Ar measurements

Schultz 1976

used as irradiated, heating

Ar-Ar

4.56

0.05

Alexander, Davis, and Lewis 1972 plateau age

Ar-Ar

4.5

0.03

Podosek and Huneke 1973a model age

weighted average calculated from three standards irradiated Ar-Ar

4.504

0.02

Alexander and Davis 1974 model age

light and dark fractions

4.383

0.03

Hohenberg et al 1981 plateau age

Olivenza (LL5)

St. Séverin (LL6)

monitor, stepwise-

Ar-Ar

and

plateau age Signer plateau age

Ar-Ar

4.42

0.03

plateau age

Ar-Ar

4.333

0.03

total age

Ar-Ar

4.359

0.03

total age

light fraction (Hohenberg et al 1981) Ar-Ar

4.4313

Ar-Ar

4.4053

dark fraction (Hohenberg et al 1981) Ar-Ar

4.4688

Ar-Ar

4.4424

single separate

using revised constants

decayMin, Reiners, Shuster 2013

one whitlockite analysis only one whitlockite analysis only

plateau age plateau age

using revised constants

decayMin, Reiners, Shuster 2013

and plateau age plateau age

phosphate

one whitlockite analysis only

and

206

Pb-207Pb 4.5536

0.0007

Göpel, Manhès, and Allègre 1994 model age

206

Pb-207Pb 4.5571

0.0015

model age

206

Pb-207Pb 4.55

0.01

Manhès, Minster, and Allègre 1978 model age

208

Pb-232Th 4.57

0.05

Manhès, Minster, and Allègre 1978 model age

238

U-206Pb

4.52

0.04

Manhès, Minster, andconcordia Allègre 1978 age

235

U-207Pb

4.54

0.02

concordia age

five phosphates (merrillite) grains U-Th/He

4.412

0.075

weighted mean of five oldest grains out of fourteenMin, Reiners, analyzed Shuster 2013

four phosphates (merrillite) grains U-Th/He

4.152

0.07

weighted mean of four oldestMin, Reiners, grains out of five analyzed Shuster 2013

interior sample

whole

U-Th/He

4.1

0.15

Eugster 1988

revised, ADOR

anchored

I-Xe

4.556

0.04

Glavin and Lugmair 2003 model age

and model age and model age

rock to

model age

Table 8. Isochron ages for some or all components of the E chondrite meteorites Abee (EH4), Hvittis (EL6), Indarch (EH4), St. Marks (EH5), and St. Sauveur (EH5), with the details and literature sources. Sample

Method

Reading

Err +/-

Note

Source

Type

Rb-Sr

4.52

two whole rock samples plotted with 12 whole rock samples from seven other meteorites Rb-Sr

4.54

0.13

Goplan and Wetherill 1970 isochron age

nine whole rock and density fractions

4.51

0.1

Minster, Rickard, and Allègre 1979 isochron age

one whole rock samples plotted with seven other whole rock samples from three other Echondrite meteorites Rb-Sr

4.516

0.029

Minster, Rickard, and Allègre 1979 isochron age

one whole rock samples plotted with seven other whole rock samples from three other Echondrite meteorites Rb-Sr

4.508

0.037

Minster, Birck, Allègre 1982

207

Pb-206Pb 4.505

0.008

Huey 1973

Pb-206Pb 4.578

0.007

Bogard, Unruh, Tatsumoto 1983

and

207

Abee (EH4) whole rock and three fractions

one whole rock sample plotted with 16 other meteorites 10 fractions from three clasts plotted with Manhès and Allègre, 1978 analyses of four meteorites

Rb-Sr

Shima 1967

and

Honda isochron age

and

and isochron age

Kohman isochron age

isochron age

Ar-Ar

4.547

0.006

Bogard, Dixon, Garrison 2010

and

Hvittis (EL6) 7–95% heating steps

Ar-Ar

4.569

0.008

Bogard, Dixon, Garrison 2010

and

7–95% heating steps

4.54

0.13

Gopalan and Wetherillisochron age

one whole rock sample plotted with 13 whole Rb-Sr

isochron age isochron age

rock samples from other meterorites

1970

Indarch (EH4) three whole rock samples plotted with five other whole rock samples from three other meteorites Rb-Sr

4.516

0.029

Minster, Rickard, and Allègre 1979 isochron age

three whole rock E-chondrite samples plotted with five other E-chondrite samples Rb-Sr

4.508

0.037

Minster, Birck, Allègre 1982

updated decay constant applied to Gopalan and Wetherill 1970 Rb-Sr

4.46

0.08

Dalrymple 1991

Rb-Sr

4.52

0.15

Bogard, Dixon, Garrison 2010

and

updated with newer decay constant

Rb-Sr

4.449

0.043

Bogard, Dixon, Garrison 2010

and

updated with newer decay constant

Rb-Sr

4.5

0.13

Bogard, Dixon, Garrison 2010

and

updated with newer decay constant

St. Marks (EH5) two whole rock samples plotted with 12 other whole rock samples of seven other meteorites Rb-Sr

4.54

0.13

Goplan and Wetherill 1970 isochron age

three whole rock samples plotted with five other whole rock samples from three other Echondrite meteorites Rb-Sr

4.516

0.029

Minster, Rickard,and Allègre 1979 isochron age

nine fractions of whole rock

Rb-Sr

4.335

0.05

Minster, Rickard, and Allègre 1979 isochron age

three whole rock samples plotted with five other whole rock samples from three other Echondrite meteorites Rb-Sr

0.037

Minster, Birck, Allègre 1982

and

4.508

Rb-Sr

4.391

0.05

Bogard, Dixon, Garrison 2010

and

updated with newer decay constant

one whole rock sample plotted with seven other whole rock samples from three other Echondrite meteorites Rb-Sr

4.516

0.029

Minster, Rickard, and Allègre 1979 isochron age

nine fractions of whole rock

Rb-Sr

4.457

0.047

Minster, Rickard, and Allègre 1979 isochron age

one whole rock sample plotted with seven other whole rock samples from three other Echondrite meteorites Rb-Sr

4.508

0.037

Minster et al 1982

updated with newer decay constant

4.514

0.047

Bogard, Dixon, Garrison 2010

Pb-206Pb 4.577

0.004

Manhès 1978

and isochron age isochron age isochron age isochron age isochron age

isochron age isochron age

St. Sauveur (EH5)

Rb-Sr

one whole rock sample plotted with three other E-chondrite meteorites

207

and

isochron age and isochron age

Allègre isochron age

Table 9. Model ages for some or all components of the E chondrite meteorites Abee (EH4), Hvittis (EL6), Indarch (EH4), St. Marks (EH5), and St. Sauveur (EH5), with the details and literature sources. Sample

Method

Reading

Err +/-

Note

Source

Type

Ar-Ar

4.5

0.03

Bogard, Unruh, Tatsumoto 1983

and

Clast 1, 1, 04

Ar-Ar

4.52

0.03

Bogard, Unruh, Tatsumoto 1983

and

Clast 2, 2, 05

Ar-Ar

4.49

0.03

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06

Ar-Ar

4.1

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 1, 1, 04 (350°C)

Ar-Ar

4.43

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 1, 1, 04 (450°C)

Ar-Ar

4.5

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 1, 1, 04 (525°C)

Abee (EH4) plateau age plateau age plateau age step-heating age step-heating age step-heating age

Bogard, Unruh, Tatsumoto 1983

and

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

4.52

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Ar-Ar

4.5

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (875°C)

Ar-Ar

4.53

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (975°C)

Ar-Ar

4.48

0.03

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (1090°C)

Ar-Ar

4.39

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (1250°C)

Ar-Ar

4.13

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (1400°C)

Ar-Ar

3.63

0.06

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (1500°C)

Ar-Ar

3.56

0.06

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (300°C)

Ar-Ar

7.2

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (400°C)

Ar-Ar

4.8

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (500°C)

Ar-Ar

4.33

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (600°C)

Ar-Ar

4.5

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (675°C)

Ar-Ar

4.52

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (750°C)

Ar-Ar

4.52

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (800°C)

Ar-Ar

4.54

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (900°C)

Ar-Ar

4.5

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (1000°C)

Ar-Ar

4.43

0.03

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (1150°C)

Ar-Ar

4.27

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (1300°C)

Ar-Ar

4.03

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 2, 2, 05 (1550°C)

Ar-Ar

3.99

0.09

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 3, 3, 06 (300°C)

Ar-Ar

8.9

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 3, 3, 06 (400°C)

Ar-Ar

5.4

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 3, 3, 06 (500°C)

Ar-Ar

3.82

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 3, 3, 06 (600°C)

Ar-Ar

4.15

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 3, 3, 06 (675°C)

Ar-Ar

4.31

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 3, 3, 06 (725°C)

Ar-Ar

4.38

0.02

Bogard, Unruh, Tatsumoto 1983

andstep-heating age

Clast 1, 1, 04 (600°C)

Ar-Ar

4.38

0.02

Clast 1, 1, 04 (650°C)

Ar-Ar

4.41

Clast 1, 1, 04 (725°C)

Ar-Ar

Clast 1, 1, 04 (800°C)

step-heating age

Ar-Ar

4.47

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (775°C)

Ar-Ar

4.49

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (850°C)

Ar-Ar

4.39

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (950°C)

Ar-Ar

4.29

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (1050°C)

Ar-Ar

4

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (1175°C)

Ar-Ar

3.76

0.02

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (1325°C)

Ar-Ar

3.58

0.09

Bogard, Unruh, Tatsumoto 1983

and

Clast 3, 3, 06 (1500°C)

207

Pb-208Pb

4.56

0.15

Bogard, Unruh, Tatsumoto 1983

and

Clast 1, 1, 01; fraction 1, 1, I

Pb-208Pb

4.72

0.05

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.56

0.1

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.45

0.07

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.7

0.1

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.54

0.13

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.41

0.03

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.56

0.1

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.7

0.06

Bogard, Unruh, Tatsumoto 1983

and

207

Pb-208Pb

4.55

0.05

Bogard, Unruh, Tatsumoto 1983

and

207

Clast 1, 1, 01; fraction 1, 1, E1 Clast 1, 1, 01; fraction 1, 1, E2 Clast 1, 1, 01; fraction 1, 1, E2 (H2O-L) Clast 2, 2, 02; fraction 2, 2, I Clast 2, 2, 02; fraction 2, 2, E Clast 2, 2, 02; fraction 2, 2, E (H2O-L) Clast 3, 3, 07; fraction 3, 3, I Clast 3, 3, 07; fraction 3, 3, E Clast 3, 3, 07; fraction 3, 3, E (H2O-L)

step-heating age step-heating age step-heating age step-heating age step-heating age step-heating age step-heating age model age model age model age model age model age model age model age model age model age model age

Hvittis (EL6) clast (whole rock)

Ar-Ar

4.47

Kinsey et al 1995

plateau age

Ar-Ar

4.544

0.018

Bogard, Dixon, and Garrison 2010 plateau age

7-95% heating steps

Ar-Ar

4.494

0.046

Bogard, Dixon, and Garrison 2010 plateau age

250°C

Ar-Ar

4.2276

0.0131

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

300°C

Ar-Ar

3.7347

0.0078

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

350°C

Ar-Ar

3.6969

0.0054

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

400°C

Ar-Ar

3.9411

0.0057

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

475°C

Ar-Ar

4.2912

0.0049

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

550°C

Ar-Ar

4.5024

0.0049

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

600°C

Ar-Ar

4.5285

0.0048

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

650°C

Ar-Ar

4.5295

0.0047

Bogard, Dixon, and Garrisonmodel (step heating)

2010

age

700°C

Ar-Ar

4.5457

0.0044

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

725°C

Ar-Ar

4.5535

0.0045

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

750°C

Ar-Ar

4.5606

0.0044

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

775°C

Ar-Ar

4.56

0.0046

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

825°C

Ar-Ar

4.5557

0.0045

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

875°C

Ar-Ar

4.5393

0.0046

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

925°C

Ar-Ar

4.5112

0.0046

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

975°C

Ar-Ar

4.4783

0.0052

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1025°C

Ar-Ar

4.4222

0.005

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1100°C

Ar-Ar

4.4498

0.0045

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1200°C

Ar-Ar

4.4444

0.0043

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1300°C

Ar-Ar

4.1384

0.0047

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1400°C

Ar-Ar

4.4291

0.0283

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

29-83% five extractions

Ar-Ar

4.249

0.013

Bogard, Dixon, and Garrison 2010 model (plateau) age

83–99% extractions

Ar-Ar

4.351

0.008

Bogard, Dixon, and Garrison 2010 model (plateau) age

525°C

Ar-Ar

3.8659

0.0059

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

625°C

Ar-Ar

4.0582

0.005

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

700°C

Ar-Ar

4.1812

0.0044

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

775°C

Ar-Ar

4.2169

0.0036

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

825°C

Ar-Ar

4.255

0.004

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

875°C

Ar-Ar

4.2538

0.0048

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

925°C

Ar-Ar

4.2492

0.0038

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

975°C

Ar-Ar

4.2275

0.0038

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1075°C

Ar-Ar

4.2525

0.0035

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1125°C

Ar-Ar

4.2977

0.0037

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1225°C

Ar-Ar

4.2958

0.0048

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1325°C

Ar-Ar

4.3511

0.0073

Bogard, Dixon, and Garrisonmodel (step heating)

Indarch (EH4)

2010

age

1450°C

Ar-Ar

4.1725

0.0149

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

whole rock

K-Ar

4.2

0.1

Schaeffer and Stoenner 1965 model age

enstatite

K-Ar

4.45

0.16

Schaeffer and Stoenner 1965 model age

relative to Shallowater

I-Xe

4.56

Busfield, Turner, and Gilmour 2008 model age

St. Marks (EH5) 71–91% extraction Ar-Ar

4.433

0.004

Bogard, Dixon, and Garrison 2010 model (maximum) age

59–71% extraction

Ar-Ar

4.411

0.005

Bogard, Dixon, and Garrison 2010 model (maximum) age

950°C

Ar-Ar

3.7429

0.0103

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1050°C

Ar-Ar

4.0609

0.0051

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1125°C

Ar-Ar

4.2363

0.004

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1200°C

Ar-Ar

4.236

0.0058

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1275°C

Ar-Ar

4.3382

0.0039

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1325°C

Ar-Ar

4.4107

0.004

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1375°C

Ar-Ar

4.4329

0.0031

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1450°C

Ar-Ar

4.3504

0.0066

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

1600°C

Ar-Ar

4.1247

0.0666

Bogard, Dixon, and Garrisonmodel (step heating) 2010 age

relative to Shallowater

I-Xe

4.56

Busfield, Turner, and Gilmour 2008 model age

I-Xe

4.56

Busfield, Turner, and Gilmour 2008 model age

St. Sauveur (EH5) relative to Shallowater

Discussion In contrast to the Allende CV3 carbonaceous chondrite meteorite (Snelling 2014), there have been fewer radioisotope methods used on these meteorites and therefore fewer radioisotope ages obtained. However, even a cursory examination of Figs. 9–16 reveals that there is still a clustering of radioisotope ages, both isochron and model ages, around 4.55–4.57 Ga. And where there are larger numbers of radioisotope ages available the clustering around 4.55–4.57 Ga is very pronounced, similar to the pattern found for Allende CV3 carbonaceous chondrite by Snelling (2014). Again this clustering is dominated by Pb-Pb isochron and model ages, and Pb-Pb calibrated Mn-Cr, Hf-W, and I-Xe ages, but it is also supported by some UPb, Th-Pb, Rb-Sr, Sm-Nd, Ar-Ar, and Re-Os ages. There is also much scattering of K-Ar, Ar-Ar, Rb-Sr, Sm-Nd, U-Pb, ThPb, Re-Os, and U-Th/He ages, though the pattern varies from meteorite to meteorite and depends on which methods were applied to them. The H Chondrites The Richardton (H5) meteorite has been the most radioisotope dated of the H chondrites, and the clustering of both its PbPb isochron and model ages at 4.55–4.57 Ga is very strong (figs 9 and 10). St. Marguerite (H4) has only Pb-Pb isochron ages that are around 4.56–4.57 Ga. As to be expected, by definition the Mn-Cr and Hf-W isochron ages coincide with the St. Marguerite’s Pb-Pb isochron ages because they have been calibrated against the St. Marguerite meteorite’s Pb-Pb isochron and model ages (figs. 9 and 10) (Göpel, Manhès, and Allègre 1994; Polnau and Lugmair 2001; Kleine et al. 2002, 2008; Trinquier et al. 2008), and the I-Xe isochron ages similarly coincide with the Pb-Pb isochron ages (fig. 9), because they are calibrated against the I-Xe isochron age of the Shallowater achondrite, which in turn is calibrated against the Pb-Pb ages of several other meteorites (Brazzle et al. 1999; Gilmour et al. 2006, 2009). Thus the Richardton (H5) meteorite’s Mn-Cr, Hf-W, and I-Xe isochron ages also coincide with its Pb-Pb isochron ages at 4.56–4.57 Ga for the same reasons. But Richardton’s Pb-Pb isochron and model 4.56–4.57 Ga ages are both supported by U-Pb isochron and model ages and a Th-Pb model age (figs. 9 and 10). Nevertheless, there is also some scatter of U-Pb, Th-Pb, Sm-Nd, and Rb-Sr isochron ages for Richardton (H5) either side of this strong 4.56–4.57 Ga clustering, plus two outlying Rb-Sr isochron ages and one outlying Sm-Nd isochron age (table 2 and fig. 9). In contrast, there is considerable wide scatter of U-Pb, Th-Pb, Ar-Ar, and Rb-Sr model ages for Richardton (H5) (table 3 and fig. 10). And there is no real pattern to this scatter. For both isochron and model ages there are U-Pb, Th-Pb, Rb-Sr, Sm-Nd, and Ar-Ar ages respectively either side of the strong 4.56–4.57 Ga clustering, although the U-Pb isochron ages are all lower (younger) than the clustering, while the U-Pb model ages are nearly all above (older) than the clustering. Furthermore, when the U-Pb and Th-Pb model ages for the same sample fractions in the same study are compared [for example, the Amelin, Ghosh, and Rotenberg (2005) data in table 3], the U-Pb model ages are for

some sample fractions older than the Th-Pb model ages, and for other sample fractions younger than the Th-Pb model ages.The other three H chondrites in tables 2 and 3, and figs. 9 and 10, have only a few radioisotope age data for them. Allegan (H5) has one Pb-Pb 4.56 Ga isochron age, one I-Xe isochron age (which via calibration agrees with the Pb-Pb isochron age) and two Pb-Pb 4.56 Ga model ages. Forest Vale (H4) has only two Mn-Cr isochron ages that are calibrated by St. Marguerite’s Pb-Pb isochron age (Polnau and Lugmair 2000, 2001), so by definition there is agreement. In contrast, the Guarena (H6) meteorite only has one Sm-Nd isochron age which is older than 4.56–4.57 Ga, whereas the four Rb-Sr isochron ages are scattered, with one at 4.56 Ga, one above 4.56 Ga, and two below 4.50 Ga. Among the model ages for these three H chondrites, the Ar-Ar model ages are all younger than their corresponding Pb-Pb-Pb model ages (fig. 10). However, whereas one Pb-Pb model age for Forest Vale (H4) is older than the other 4.56 Ga Pb-Pb model age, all four PbPb model ages for Guarena (H6) are younger than the 4.56–4.57 Ga “target,” and all six Ar-Ar model ages are much younger. This could well be related to the classification of these meteorites on a scale of increasing thermal metamorphism from H4 through to H6 (fig. 6) based on the observable and measurable criteria listed in fig. 5 (Norton 2002; Van Schmus and Wood 1967). It is thus logical that the U-Pb and K-Ar systems in the more thermally metamorphosed (to higher temperatures) Guarena (H6) meteorite have been disturbed, some of the daughter Ar gas particularly having been lost and thus resulting in younger Ar-Ar measured ages. The L Chondrites All three meteorites investigated have only a few isochron and model ages via only a few radioisotope dating methods (tables 4 and 5, and figs. 11 and 12). However, the clustering of the radioisotope ages is again around the 4.55–4.57 Ga mark. This “target” date was achieved by both Pb-Pb and U-Pb isochron ages for Bardwell (L5) and Bjurböle (L4), and by both Pb-Pb and U-Pb model ages for Bardwell (L5), but only by Pb-Pb model ages for Bjurböle (L4). One Rb-Sr, one I-Xe, and two Sm-Nd isochron ages also cluster around the 4.55–4.57 Ga mark for Bjurböle (L4), but one Rb-Sr isochron age is slightly younger and one Sm-Nd isochron age is very much younger. The I-Xe isochron age, though initially designated as the I-Xe standard (Hohenberg and Kennedy 1981), by definition agrees with Bjurböle’s Pb-Pb isochron age, because its I-Xe isochron age has also been calibrated against the I-Xe isochron age of the Shallowater achondrite, which in turn is calibrated against the Pb-Pb ages of several other meteorites (Brazzle et al. 1999; Gilmour et al. 2006, 2009). The other patterns are that for both Bardwell (L5) and Bjurböle (L4) the K-Ar and Ar-Ar model ages are consistently younger than the “target” age, while one Pb-Pb model age for each meteorite is well above (much older) than the 4.55–4.57 Ga cluster. The sole U-Th/He model age for Bjurböle (L4), similar to its K-Ar and Ar-Ar model ages, is much younger than the 4.55–4.57 Ga mark (fig. 12), probably because these methods depend on daughter isotopes He and Ar that are noble (inert) gases of light atomic weights and small sizes which therefore are prone to diffusing away from their parent radioisotopes and escaping completely from the host mineral lattices. Indeed, it has been suggested that severe heating after meteorite formation may cause total loss of both gases, which results in the He and Ar ages being younger and concordant, with both clocks reset to zero at the time of the heating event after the meteorites formed (Lewis 1997). Furthermore, where U-Th/He ages are younger than K-Ar and Ar-Ar ages, as here for the Bjurböle (L4) chondrite (fig. 12), it has been suggested that even moderate heating of the meteorites would have caused He to diffuse out of the mineral grains in a time too short for major loss of the more slowly diffusing Ar.As a more thermally metamorphosed meteorite, Bruderheim (L6) displays a slightly different pattern, consistent with disturbance of the radioisotope systems. Among the few isochron ages it is the two U-Pb and single Rb-Sr isochron ages that cluster around the 4.55–4.57 Ga mark, while the single Pb-Pb isochron age is less than 4.50 Ga (fig. 11). However, among the model ages it is the Pb-Pb model ages that cluster close to and just below the 4.55–4.57 Ga mark, while the U-Pb model ages are widely scattered both well above (older) and well below (younger), and around the 4.55–4.57 Ga mark. The LL Chondrites Only two LL chondrites have been radioisotope dated multiple times. For the Olivenza (LL5) meteorite only Rb-Sr isochron and Ar-Ar model ages have been obtained (figs. 13 and 14), and these are somewhat scattered with respect to the 4.55– 4.57 Ga mark, with one Rb-Sr isochron age above and the other ages below. In contrast, the St. Séverin (LL6) meteorite’s age has been well constrained by one Rb-Sr, one Re-Os, three Pb-Pb, and one Sm-Nd 4.56–4.57 Ga isochron ages (fig. 13), and by three Pb-Pb, one Th-Pb, and one Ar-Ar 4.56–4.57 Ga model ages (fig. 14). These 4.56–4.57 Ga ages are also supported by Mn-Cr isochron and I-Xe isochron and model ages, as is to be expected because of these methods being calibrated against Pb-Pb isochron and model ages for other meteorites (Brazzle et al. 1999; Gilmour et al. 2006, 2009; Kleine et al. 2008; Polnau and Lugmair 2001; Trinquier et al. 2008). Again there is also scatter, with Re-Os, Rb-Sr, and PbPb isochron ages above the 4.56–4.57 Ga mark, and Rb-Sr and Pb-Pb isochron ages below. In contrast, apart from one KAr model age above the 4.56–4.57 Ga mark (table 7), all the other K-Ar and Ar-Ar (bar one) model ages, and the U-Pb and U-Th/He model ages, are below the 4.56–4.57 Ga mark. In fact, many of the Ar-Ar, K-Ar, and U-Th/He model ages are well below the 4.56–4.57 Ga mark (table 7), with a clustering of such model ages centred around the 4.00–4.20 Ga mark. Two UTh/He ages are lower outliers. The probable explanation for this pattern would seem to be that these methods depend on daughter isotopes that are noble (inert) gases of light atomic weights and small sizes which therefore are prone to diffusing away from their parent radioisotopes and escaping completely from the host mineral lattices, especially due to a heating event subsequent to meteorite formation (Lewis 1997). Conventionally this 4.00–4.20 Ga age clustering would be identified as the age of such a re-heating event that reset the K-Ar, Ar-Ar, and U-Th/He model ages due to the loss of Ar and He gases (Bogard 2011; Min, Reiners, and Shuster 2013; Trieloff et al. 2003). The E Chondrites Five E chondrites have been dated by more than one radioisotope method—four by the Rb-Sr and Pb-Pb isochron methods and one by the Ar-Ar and Rb-Sr isochron methods (fig. 15); two by the Ar-Ar and Pb-Pb model age methods, two by the KAr, Ar-Ar, and I-Xe model age methods, and one just by the I-Xe model age method (fig. 16). None of the methods produced results on these meteorites that clustered at the 4.56–4.57 Ga mark, except for the I-Xe model ages for Indarch (EH4), St. Marks (EH5), and St. Sauveur (EH5). These are by definition in agreement with this 4.56–4.57 age, because I-Xe ages are always calibrated against the I-Xe age of the Shallowater achondrite (Busfield, Turner, and Gilmour 2008), which in turn is calibrated against the Pb-Pb ages of several other meteorites that date at the 4.56–4.57 Ga mark (Brazzle et al. 1999; Gilmour et al. 2006, 2009). However, some individual age determinations did produce results in the 4.56–4.57 Ga range— one Ar-Ar isochron age for Hvittis (EL6), one Rb-Sr isochron age for Indarch (EH4), and one Pb-Pb isochron age for St. Sauveur (EH5) (fig.15); four Pb-Pb model ages for Abee (EH4), and four Ar-Ar model ages for Hvittis (EL6) (fig.16). Otherwise, in general the Rb-Sr isochron ages for these meteorites are younger than the 4.56–4.57 Ga “target” age (except for the one Rb-Sr isochron age for Indarch that is in that range), and younger than or equal to all of both the Pb-Pb and ArAr isochron ages, the one exception being an Abee (EH4) Pb-Pb isochron age (fig. 15). This pattern of isochron ages for these two β-decaying radioisotope systems is not consistent with that reported by the RATE project, which found that K-Ar and Ar-Ar isochron ages were always younger than Rb-Sr isochron ages (Snelling 2005; Vardiman, Snelling and Chaffin 2005). Among the model ages the Ar-Ar (and the two K-Ar) model ages are widely scattered and invariably are younger than

both the 4.55–4.57 Ga target age and the Pb-Pb model ages, except for the four Hvittis (EL6) Ar-Ar ages in the 4.55–4.57 Ga range, and the four Abee (EH4) Ar-Ar model ages greater than 4.8 Ga (fig. 16). Both the K-Ar and Pb-Pb systems seem to have been affected in the Abee (EH4) meteorite, as the Pb-Pb model ages are scattered between 4.42 and 4.72 Ga (table 9), which is much less that the scatter in the Ar-Ar model ages between 3.56 and 8.9 Ga. The usual explanation for disturbance of the K-Ar (and Ar-Ar) system is a heating event sometime after formation of the meteorite’s parent body (Bogard 2011; Min, Reiners, and Shuster 2013; Trieloff et al. 2003), so that might explain this pattern in these E chondrites. The U-Pb system if usually perturbed by earth surface weathering, so perhaps the Abee (EH4) chondrite was affected by water on the earth’s surface before it was recovered for study. Comparisons to the RATE Study One of the issues Snelling (2014) discussed in relation to the radioisotope ages that have been obtained for the Allende CV3 carbonaceous chondrite is whether the meteorite yielded a pattern of isochron ages similar to that found for earth rocks by the 1997–2005 RATE (radioisotopes and the age of the earth) project (Vardiman, Snelling, and Chaffin 2005). The major conclusion of the RATE project was that radioisotope decay rates have not necessarily been constant throughout earth history, because there is evidence that there have been one or more episodes of accelerated rates of radioisotope decay, particularly during the Flood only about 4350 years ago (Vardiman, Snelling, and Chaffin 2005). While there were several lines of documented evidence that confirmed this conclusion, the principal evidence was different isochron ages obtained from the same samples from the same rock units by the different radioisotope dating methods (Snelling 2005; Vardiman, Snelling, and Chaffin 2005). Furthermore, there was a consistent pattern to the isochron ages from the different methods that indicated that there was an underlying systematic cause of these age differences, namely, an episode (or episodes) of accelerated radioisotope decay (Snelling 2005; Vardiman, Snelling, and Chaffin 2005). For example, it was found that the αdecaying radioisotopes U and Sm always gave older ages than the β-decaying K and Rb. And then between the β-decayers, K with the shorter half-life (more rapid decay today) and the lighter atomic weight, always yielded younger ages than the slower decaying and heavier Rb. While exactly the same pattern was not confirmed among the α-decaying U and Sm radioisotopes, both their half-lives and atomic weights were still believed to be the factors at work. The mechanism proposed for this past episode (or episodes) of accelerated radioisotope decay was small changes to the binding forces in the nuclei of the parent radioisotopes (Vardiman, Snelling, and Chaffin 2005). These changes would thus have to have affected every atom making up the earth, and by logical extension every atom of the universe at the same time. The designer Himself is not bound by those physical laws which He can change at any time anywhere or everywhere. Therefore, we should expect that this past episode(s) of accelerated radioisotope decay had affected the asteroids from where many meteorites have come, and that the meteorites may thus today yield the same pattern of different radioisotope ages from the different radioisotope dating methods.Snelling (2014) found no pattern of isochron ages similar to the patterns found in the RATE study was yielded by the Allende CV3 carbonaceous chondrite, and the same is true of the isochron ages for the fifteen H, L, LL, and E chondrites reported in this study, as already discussed above. In fact, the β-decay isochron ages (Rb-Sr, Re-Os) are sometimes older than the α-decay (U, Sm) isochron ages. Furthermore, the E chondrites yielded Rb-Sr isochron ages generally younger than or equal to their Ar-Ar isochron ages (table 8 and fig. 15), when the pattern in the RATE study’s rocks was the opposite because Rb has a longer half-life and a heavier atomic weight. In contrast, the ReOs isochron ages yielded by the St. Séverin (LL6) chondrite were greater than or equal to its Rb-Sr isochron ages (table 6 and fig. 13). While the RATE study didn’t deal with Re-Os isochron ages, this pattern is arguably somewhat predictable from the conclusions of the RATE study, because while the β-decaying Re has a slightly shorter half-life (at 42.7 billion years) than the β-decaying Rb (at 48.8 billion years), it has a heavier atomic weight (187 for Re compared to 87 for Rb) (Faure and Mensing 2005). So if the atomic weight is the dominant factor in the amount of accelerated radioisotope decay which occurred, then the Re-Os isochron ages should be older than the Rb-Sr isochron ages, though the effect of the half-lives may result in the occasional equality of their isochron ages.Extending this argument further, if the atomic weight is the dominant factor in the amount of accelerated radioisotope decay which occurred, then among the α-decaying parent radioisotopes the Pb-Pb isochron ages should be older than the Sm-Nd isochron ages, because the parent U radioisotopes have atomic weights of 238 and 235, whereas the parent Sm radioisotope’s atomic weight is only 147. But again the heavier atomic weight U radioisotopes have shorter half-lives (at 4.47 billion years and 0.704 billion years respectively) than Sm (at 106 billion years) (Faure and Mensing 2005). So the Pb-Pb isochron ages are mostly older (or equal to) the Sm-Nd isochron age of the St Séverin (LL6) chondrite (table 6 and fig. 13), but this is not the case with the Bjurböle (L4) chondrite (table 4 and fig. 11) and the Richardton (H5) chondrite (table 2 and fig. 9), where some Sm-Nd isochron ages are older than the PbPb isochron ages. So again the effect of the half-lives may result in the occasional equality or reversal in the pattern of their isochron ages.It is therefore fairly obvious that there are no clear and consistent patterns in these meteorite isochron ages comparable to the patterns of isochron ages obtained in the RATE study. However, there is a major difference between the RATE study and these studies on meteorites, in that the RATE study investigated earth rocks that yielded isochron ages of less than 3 Ga, whereas these meteorites come from elsewhere in the solar system and generally yield 4–5 Ga ages. So the origin of these meteorites could well have a major bearing on the radioisotope ages they yield, as initially discussed by Snelling (2014). The Origin of Meteorites from Asteroids There is unanimity among astronomers and planetary geologists that most meteorites come from asteroids, which are primarily orbiting the Sun in the asteroid belt between Mars and Jupiter (Libourel and Corrigan 2014). There is also unanimity among conventional scientists that the asteroids represent leftover precursors to the terrestrial planets (MercuryMars) (Michel 2014). They postulate that about 4.56 billion years ago the early solar system consisted of a rotating disk of gas and dust, called the protoplanetary disk, revolving around the sun. Planets then supposedly formed from that disk, and different populations of small bodies, in particular the main belt asteroids between the orbits of Mars and Jupiter, survived as remnants of that era.According to current conventional models, the asteroid belt that remained at the end of the planetforming processes was probably very different from the current main belt, perhaps containing an earth mass or more of material in planetary embryos with masses similar to the Moon or Mars, as well as tens, hundreds, or thousands of times more bodies like the asteroid 4 Vesta and the dwarf planet 1 Ceres than are present in the main belt today (Michel 2014). Throughout its history the asteroid belt appears to have been shaped by collisional processes, such as cratering, disruption, and the generation of new asteroids as collisional fragments. The net result is that the total mass of the main asteroid belt today is only about 4% of the Moon’s mass, or less than 1/1000th of the Earth’s mass (Libourel and Corrigan 2014). So it would appear that the asteroid belt has been significantly depleted of asteroids since its early history.Orbital resonances, when two bodies have orbital periods that are a simple integer ratio of each other, may lead to destabilization of the orbits of small bodies (Libourel and Corrigan 2014). Within the main asteroid belt, objects that have orbital periods in resonance with the orbital period of Jupiter are gradually ejected into different, random orbits, leading to the removal of asteroids from regions within the main asteroid belt that are now empty. Another important resonance is that between asteroids and Saturn, which has formed the inner boundary of the main asteroid belt, and which is responsible for delivering asteroids into planet-

crossing orbits. Once asteroids become Mars-crossers they are usually ejected from the main asteroid belt due to close encounters with Mars’ gravitational field. If Mars-crossing asteroids fail to interact with Mars, then their orbital semi-major axes are gradually reduced and they become Near Earth Asteroids (NEAs).Asteroids that are nudged by the gravitational attraction of nearby planets or have significant inclination and eccentricity may collide with other bodies traveling along different orbits (Libourel and Corrigan 2014). Even if the current impact probability appears low, collisions between asteroids are not rare, and do not appear to have been rare in the past. Depending on the relative impact velocity between the bodies and on their sizes, collisions result in 1) fragmentation of a parent asteroid into several large pieces, and/or 2) the formation of fine, micron-sized asteroidal dust. A collision between large asteroids brings into play both fragmentation and gravitation (Michel 2014). The asteroids are partially to totally shattered, and subsequent gravitational attraction between fragments leads to reaccumulation, which finally forms an entire family of large and small objects (new asteroids). Accordingly, most of the smaller asteroids are thought to be piles of rubble held together loosely by gravity (Michel and Richardson 2013; Tsuchiyama 2014). The largest asteroids, those larger than 125 km (200 mi) in diameter, however, are probably primordial objects that have never been disrupted (Asphaug 2009; Michel 2014). Asteroids are therefore currently thought to have been quite mobile within the main belt. Due to asteroid collisions and other effects, main belt asteroids migrate, passing through the orbital resonances to end up crossing the orbits of Mars, Earth, Venus, and even Mercury (Libourel and Corrigan 2014). NEAs do not have stable orbits, so they have relatively short lifetimes. Once the orbits of asteroids whose diameters exceed 100–150 m (330–490 ft) are within 7.5 million km (4.7 million mi) of the earth’s orbit, there is a greater possibility of them colliding with the earth and impacting its surface. By definition, meteors are asteroids that enter the earth’s atmosphere. Due to their high entry velocity (several kilometers per second) they are heated to high temperatures as they are slowed by the atmosphere. This produces visible paths, and the meteors are then known as fireballs or shooting stars. If the meteors survive their plunge through the atmosphere and land on the earth’s surface, they are classified as meteorites. From these orbital and dynamical arguments, it is believed that most meteorites have indeed come from the asteroid belt and therefore are samples of asteroidal materials (Cloutis, Binzel, and Gaffey 2014; Libourel and Corrigan 2014). However, linking meteorites to their parent asteroids is a complicated issue. There is a photographic technique that has been used to get estimates of the orbital parameters (approximately) of meteors before they make contact with earth’s atmosphere. Two cameras have to have synchronized shutters and photograph the object before it makes contact with the atmosphere. This has been done for a few cases of meteors and the orbital elements suggest the objects did come from the asteroid region. So there are some cases where this has been done and then fragments of the photographed objects were found, which has established good indications of meteorites coming from asteroids. Furthermore, there have been a multitude of methods used to investigate asteroids, such as earth-based radar imaging, optical and radar polarimetry, thermal-infrared observations, reflectance spectroscopy, and thermal emission spectroscopy, but only the availability of meteorites of known provenance has enabled additional confirmation of asteroid-meteorite links. Two recent examples confirming the asteroidmeteorite link are relevant to the H, L, LL, and E chondrites in this study.On October 6, 2008, the small, ~4 m (13 ft) wide asteroid 2008 TC3 was discovered and predicted to hit the earth within ~19 hours (Goodrich, Bischoff, and O’Brien 2014). Early morning, October 7, 2008, eyewitnesses saw the fireball that resulted when the asteroid hit the earth’s atmosphere above the Nubian Desert of northern Sudan, Africa. A few seconds later, at ~37 km (23 mi) above the earth, the asteroid was shattered in the atmosphere by dynamic ram pressures in a series of explosions into fragments. Approximately 700 cmsized (275 in-sized) fragments were subsequently recovered and constitute what became known as the Almahata Sitta meteorite. Study of their physical, chemical, and mineralogical properties has revealed that the fragments are remarkably heterogeneous. The most abundant samples are ureilitic lithologies (see fig. 1— URE among the Primitive Achondrites) with various olivine/pyroxene ratios, mineral compositions and grain sizes (Bischoff et al. 2010; Goodrich, Bischoff, and O’Brien 2014). Among the chondritic samples, enstatite (E) chondrites are the most abundant, including both E chondrite subgroups (EL and EH), though the EL subgroup dominates, with representatives of the various petrologic types (EL3, EL4, EL5, and EL6), which are indistinguishable from previously known E chondrites. So far, several L and H group ordinary (O) chondrites have also been analysed. It has been concluded that the 2008 TC3 asteroid was not solid rock, but consisted mostly of finegrained, highly porous matrix material, weakly cementing a small fraction of isolated, centimeter-sized fragments of denser rocks that became the fallen meteorite.In June 2010 the Japanese spacecraft Hayabusa successfully returned to earth with fine particles collected in September 2005 from the surface of Near Earth Asteroid 25143 Itokawa (Nakamura et al. 2011; Tsuchiyama 2014). Measuring 30–180 μm (0.0011–0.007 in) in diameter, initial analyses of the mineralogy, micropetrology, and elemental and isotopic compositions of the returned regolith particles from asteroid Itokawa indicate that these dust particles are identical to thermally metamorphosed LL chondrites, particularly the LL5 and LL6 ordinary chondrites, such as Olivenza and St. Séverin (respectively) in this study. Conclusions After decades of numerous careful radioisotope dating investigations of ordinary (O) chondrite meteorites (H, L, and LL groups) and enstatite (E) chondrite meteorites their Pb-Pb isochron age of 4.55–4.57 Ga has been well established. This date for these chondrite meteorites is supported for some of them by a strong clustering of their Pb-Pb isochron and model ages in the 4.55–4.57 Ga range, as well as being confirmed by both isochron and model age results via the U-Pb method, and to a lesser extent, by the Ar-Ar, Rb-Sr, Re-Os, and Sm-Nd methods. The Hf-W, Mn-Cr, and I-Xe methods are all calibrated against the Pb-Pb isochron method, so their results are not objectively independent. Thus the Pb-Pb isochron dating method stands supreme as the ultimate, most precise tool for determining the ages of the chondrite meteorites.There are only two other discernible patterns in the isochron and model ages for these O and E chondrites, apart from scatter of the U-Pb, Th-Pb, Rb-Sr, and Ar-Ar model ages particularly. These chondrite ages do not follow the systematic pattern found in Grand Canyon Precambrian rock units during the RATE project. The α-decay ages are not always older than the β-decay ages for particular meteorites, and among the β-decayers the ages are not always older according to the increasing heaviness of the atomic weights of the parent radioisotopes, but may have also been modified according to the lengths of their half-lives. Thus there appears to be no consistent evidence in these O and E chondrite meteorites similar to the evidence found in earth rocks of past accelerated radioisotope decay.Any explanation for the 4.55–4.57 Ga age for these O and E chondrite meteorites needs to consider the origin of meteorites. Most meteorites appear to be fragments derived from asteroids via collisions, but even in the naturalistic paradigm the asteroids, and thus the meteorites, are regarded as “primordial material” left over from the formation of the solar system.If some of the daughter isotopes were thus “inherited” by these O and E chondrite meteorites when they were formed from that “primordial material,” and the parent isotopes in the meteorite were also subject to some subsequent accelerated radioisotope decay, then the 4.55–4.57 Ga Pb-Pb isochron “age” for these O and E chondrite meteorites cannot be their true real-time age, which according to the creation paradigm is only about 6000 real-time years.

However, these conclusions and the suggested explanation can at best be regarded as tentative and interim while their confirmation or adjustment awaits the examination of more radioisotope dating data from many more meteorites. Furthermore, further extensive studies of the radioisotope dating of many more earth rocks from all levels within the whole geologic record are required to attempt to systematize the proportions of isotopes in each radioisotope dating system measured today that are due to inheritance from the “primordial material,” past accelerated radioisotope decay, and mixing, additions and subtractions in the earth’s mantle and crust through earth history, particularly during the Day Three Upheaval and then subsequently during the Flood. Such studies are already in progress. Acknowledgments The invaluable help of my research assistant Lee Anderson, Jr., in compiling these radioisotope dating data into the tables and then plotting the data in the color coded age versus frequency histogram diagrams is acknowledged. Radioisotope Dating of Meteorites: III. The Eucrites (Basaltic Achondrites) by Dr. Andrew A. Snelling on December 31, 2014 Abstract Meteorites date the earth with a 4.55 ± 0.07 Ga Pb-Pb isochron called the geochron. They appear to consistently yield 4.55–4.57 Ga radioisotope ages, adding to the uniformitarians’ confidence in the radioisotope dating methods. Achondrites, meteorites not containing chondrules, account for about 8% of meteorites overall. About 3% of the witnessed falls of all meteorite types are the achondrites known as eucrites, which makes them the fourth-most-common meteorite to fall. Eucrites are similar to basalts and are believed to be space debris from the crust of main belt asteroid 4-Vesta. Many radioisotope dating studies in the last 45 years have used the K-Ar, Ar-Ar, Rb-Sr, Sm-Nd, U-Th-Pb, Lu-Hf, Mn-Cr, Hf-W, AlMg, I-Xe, and Pu-Xe methods to yield an abundance of isochron and model ages for these basaltic achondrites from wholerock samples, and mineral and other fractions. Such age data for 12 eucrites were tabulated and plotted on frequency versus age histogram diagrams. They strongly cluster in many of these eucrites at 4.55–4.57 Ga, dominated by Pb-Pb and U-Pb isochron and model ages, testimony to that technique’s supremacy as the uniformitarians’ ultimate dating tool, which they consider very reliable. These ages are confirmed by Rb-Sr, Lu-Hf, and Sm-Nd isochron ages, but agreement could be due to calibration with the Pb-Pb system. There is also scatter of the U-Pb, Pb-Pb, Th-Pb, Rb-Sr, K-Ar, and Ar-Ar model ages, in most cases likely due to thermal disturbances resulting from metamorphism or impact cratering of the parent asteroid. No pattern was found in these meteorites’ isochron ages similar to the systematic patterns of isochron ages found in Precambrian rock units during the RATE project, so there is no evidence of past accelerated radioisotope decay having occurred in these eucrites, and therefore on their parent asteroid. This is not as expected, yet it is the same for all meteorites so far studied. Thus it is argued that accelerated radioisotope decay must have only occurred on the earth, and only the 500–600 million years’ worth we have physical evidence for during the Flood. Otherwise, due to their 4.55–4.57 Ga “ages” these eucrites and their parent asteroid are regarded as originally representing “primordial material” Today’s measured radioisotope compositions of these eucrites could reflect a geochemical signature of that “primordial material,” which included atoms of all elemental isotopes. So if most of the measured daughter isotopes were already in these basaltic achondrites when they were formed on their parent asteroid, then their 4.55–4.57 Ga “ages” obtained by Pb-Pb and U-Pb isochron and model age dating are likely not their true real-time ages, which according to the creation paradigm is only about 6000 real-time years. Further investigation of radioisotope ages data for meteorites in remaining groups of achondrites, for lunar rocks, and for rocks from every level in the earth’s geologic record, should enable the interim ideas presented here to be confirmed or modified. Keywords: meteorites, classification, achondrites, eucrites, asteroids, 4-Vesta, radioisotope dating, Bereba, Cachari, Caldera, Camel Donga, Ibitira, Juvinas, Moama, Moore County, Pasamonte, Serra de Magé, Stannern, Yamato 75011, K-Ar, Ar-Ar, Rb-Sr, Sm-Nd, U-Th-Pb, Lu-Hf, Mn-Cr, Hf-W, Al-Mg, I-Xe, Pu-Xe, isochron ages, model ages, discordant radioisotope ages, accelerated radioactive decay, thermal disturbance, resetting, “primordial material,” geochemical signature, mixing, inheritance Introduction In 1956 Claire Patterson at the California Institute of Technology in Pasadena reported a Pb-Pb isochron age of 4.55 ± 0.07 Ga for three stony and two iron meteorites, which since then has been declared the age of the earth (Patterson 1956). Adding weight to that claim is the fact that many meteorites appear to consistently date to around the same “age” (Dalrymple 1991, 2004), thus bolstering the evolutionary community’s confidence that they have successfully dated the age of the earth and the solar system at around 4.56 Ga. These apparent successes have also strengthened their case for the supposed reliability of the increasingly sophisticated radioisotope dating methods.Creationists have commented little on the radioisotope dating of meteorites, apart from acknowledging the use of Patterson’s geochron to establish the age of the earth, and that many meteorites give a similar old age. Morris (2007) did focus on the Allende carbonaceous chondrite as an example of a well-studied meteorite analyzed by many radioisotope dating methods, but he only discussed the radioisotope dating results from one, older paper (Tatsumoto, Unruh, and Desborough 1976).In order to rectify this lack of engagement by the creationist community with the meteorite radioisotope dating data, Snelling (2014a) obtained as much radioisotope dating data as possible for the Allende CV3 carbonaceous chondrite meteorite (due to its claimed status as the most studied meteorite), displayed the data, and attempted to analyze them. He found that both isochron and model ages for the total rock, separated components, or combinations of these strongly clustered around a Pb-Pb age of 4.56–4.57 Ga, the earliest (Tatsumoto, Unruh, and Desborough 1976) and the latest (Amelin et al. 2010) determined Pb-Pb isochron ages at 4.553 ± 0.004 Ga and 4.56718 ± 0.0002 Ga respectively being essentially the same. Apart from scatter of the U-Pb, Th-Pb, Rb-Sr, and Ar-Ar ages, no systematic pattern was found in the Allende isochron and model ages similar to the systematic pattern of isochron ages found in Precambrian rock units during the RATE project that was interpreted as produced by an episode of past accelerated radioisotope decay (Snelling 2005c; Vardiman, Snelling, and Chaffin 2005).Snelling (2014b) subsequently gathered together all the radioisotope ages obtained for 10 ordinary (H, L, and LL) and five enstatite (E) chondrites and similarly displayed the data. They generally clustered, strongly in the Richardton (H5), St. Marguerite (H4), Bardwell (L5), Bjurbole (L4), and St. Séverin (LL6) ordinary chondrite meteorites, at 4.55–4.57 Ga, dominated by Pb-Pb and U-Pb isochron and model ages, but confirmed by Ar-Ar, Rb-Sr, Re-Os, and Sm-Nd isochron ages. There was also scatter of the U-Pb, ThPb, Rb-Sr, and Ar-Ar model ages, in some cases possibly due to thermal disturbance. Again, no pattern was found in these meteorites’ isochron ages indicative of past accelerated radioisotope decay.Snelling (2014a, b) then sought to discuss the possible significance of this clustering in terms of various potential creationist models for the history of radioisotopes and their decay. He favored the idea that asteroids and the meteorites derived from them are “primordial material” left over from the formation of the solar system, which is compatible Thus he argued that today’s measured radioisotope compositions of all these chondrites may reflect a geochemical signature of that “primordial material,” which included atoms of all elemental isotopes. So if some of the daughter isotopes were already in these chondrites when they were formed, then the 4.55–4.57 Ga “ages” for them obtained by Pb-Pb and U-Pb isochron and model age dating are likely not their true real-time ages,

which according to the creation paradigm is only about 6000 real-time years.However, Snelling (2014a, b) admitted that drawing firm conclusions from the radioisotope dating data for just these 16 chondrite meteorites was premature, and recommended further studies of more meteorites. This present contribution is therefore designed to further document the radioisotope dating data for more meteorites, the basaltic achondrites or eucrites, so as to continue the discussion of the potential significance of these data. The Classification of Achondrite Meteorites The most recent classification scheme for the meteorites is that of Weisberg, McCoy, and Krot (2006), which is reproduced in Fig. 1. Based on their bulk compositions and textures, Krot et al. (2005) divided meteorites into two major categories, chondrites (meteorites containing chondrules) and achondrites (meteorites not containing chondrules or non-chondritic meteorites). They further subdivided the achondrites into primitive achondrites and igneously differentiated achondrites. However, Weisberg, McCoy, and Krot (2006) simply subdivided all meteorites into three categories—chondrites, primitive achondrites and achondrites (fig. 1).The non-chondritic meteorites contain virtually none of the components found in chondrites. It is conventionally claimed that they were derived from chondritic materials by planetary melting, and that fractionation caused their bulk compositions to deviate to various degrees from chondritic materials (Krot et al. 2005). The degrees of melting that these rocks experienced are highly variable, and thus, these meteorites have been divided into the two major categories—primitive and differentiated. However, there is no clear cut boundary between these categories.The differentiated non-chondritic meteorites, or achondrites (fig. 1), are conventionally regarded as having been derived from parent bodies that experienced large-scale partial melting, isotopic homogenization (ureilites are the only exception), and subsequent differentiation. Based on abundance of FeNi-metal, these meteorites are commonly divided into three types— achondrites, stony-irons, and irons. Each of these types contains several meteorite groups and ungrouped members (fig. 1). Several groups of achondrites and iron meteorites are likely to be genetically related and were possibly derived from single asteroids or planetary bodies.The achondrites account for about 8% of meteorites overall, and the majority of them (about two-thirds) are HED meteorites (howardites, eucrites, and diogenites), believed to have originated from the crust of asteroid 4-Vesta (Norton 2002) (fig. 1). Other types include martian, lunar, and several types thought to originate from as-yet unidentified asteroids. These groups have been determined on the basis of, for example, their bulk Fe/Mn and 17O/18O ratios, which are thought to be characteristic “fingerprints” for each parent body (Mittlefehldt et al. 1998).The achondrites represent the products of classical igneous processes acting on the silicate-oxide system of asteroidal bodies—partial to complete melting, differentiation, and magmatic crystallization (Mittlefehldt 2005). Iron meteorites represent the complimentary metalsulfide system products of this process. Thus the achondrites consist of materials similar to terrestrial basalts and plutonic rocks, so they exhibit igneous textures, or igneous textures modified by impact and/or thermal metamorphism, and distinctive mineralogies indicative of igneous processes.The HED meteorites are sometimes grouped with the angrites and aubrites (fig. 1) and termed the asteroidal achondrites, because of all having been differentiated on parent asteroidal bodies. The howardite-eucrite-diogenite (HED) meteorites have been traditionally classified into the one clan, because there is strong evidence they originated on the same parent body, the asteroid 4-Vesta (Binzel and Xu 1993; Consolmagno and Drake 1977; Drake 2001; Mandler and Elkins-Tanton 2013; McCord, Adams, and Johnson 1970; McSween et al. 2011; McSween et al. 2013, 2014; Righter and Drake 1997). This was one of the first links made between meteorites and an asteroid (Cloutis, Binzel, and Gaffey 2014; McCord, Adams, and Johnson 1970). Initially their spectroscopic similarity, which suggested the HED achondrites are impact ejecta off 4-Vesta, was deemed dynamically dubious owing to the apparent lack of a plausible pathway from Vesta to the earth. The discovery of the Vesta family of asteroids or “Vestoids” (Binzel and Xu 1993) extending from Vesta to resonance delivery zones solidified the link. This link has stood the test of time and has been confirmed by the in situ results provided by the Dawn mission to this asteroid (McSween et al. 2014). Thus the HED clan allows the confident association of specific types of igneous processes with an asteroid body of known size.

Fig. 1. The classification system for meteorites (after Weisberg, McCoy, and Krot 2006). (Click image for larger view.) The HED clan is the most extensive suite of differentiated crustal rocks from an asteroid (Mittlefehldt 2005). Evidence that these achondrites belong in the same clan includes their identical oxygen isotopic compositions (Clayton and Mayeda 1996), similarities in Fe/Mn ratios in pyroxenes, the occurrence of polymict breccias consisting of materials of eucritic and diogenitic parentage (for example, the howardites), and the existence of rocks intermediate between diogenites and cumulate eucrites (Krot et al. 2005). The suite of meteorites comprising the HED clan is composed of mafic and ultramafic igneous rocks, most of which are breccias. The parent lithologies were mostly metamorphosed, which has obscured original igneous zoning in most cases (Mittlefehldt 2005). The suite contains four main igneous lithologies—basalt and cumulate gabbro (eucrites), and orthopyroxenite and harzburgite (diogenites). When both eucrite and diogenite clasts are present in a meteorite that is a polymict breccia, then it is a howardite. These lithologies are consistent with a postulated layered crust model for the HED parent body, 4-Vesta (Mandler and Elkins-Tanton 2013; McSween et al. 2013, 2014; Righter and Drake 1997; Takeda 1997). The Eucrites The eucrites are the most common of the achondrites. About 3% of the witnessed falls of all meteorite types are eucrites, which makes them the fourth most common meteorite to fall (Norton 2002). Of the HED meteorites, eucrites are by far the most common, about 52%. Until the meteorite finds in Antarctica became available with their large cache of eucrites, eucrites were defined as monomict breccias. However, the large number of eucrites recovered that show a wide variation of lithic fragments, unlike the fragments in howardites, has prompted the acceptance of eucrites as either monomict or polymict.The most obvious external characteristic of a freshly fallen eucrite is its very black and lustrous fusion crust

compared to the dull black crust of a chondrite, due to the intense heating of the outer surface during passage through the earth’s atmosphere (Norton 2002). Eucrites are Ca-rich and this combined with the usually present small amount of Fe gives these meteorites a “wet” look (fig. 2). Fusion crusts form in the final second or two of the ablation process as meteorites pass rapidly through the earth’s atmosphere during the fireball stage. The fusion crusts then rapidly cool, so contraction cracks often form, leaving the outer surface of the meteorites looking much like the crazing on pottery (figs. 2 and 3).The similarities of eucrites chemically and petrographically to terrestrial basalts is frequently noted, but a broken face of a eucrite exposes a light gray interior, which is unlike the dark gray to black interiors of terrestrial basalts. Eucrite textures are also fine-grained, and often glomeroporphyritic due to clumps of phenocrysts set in the groundmass. This is typical of terrestrial volcanic rocks that have cooled more slowly, producing glomerocrysts of interlocking plagioclase and pyroxene crystals. If basaltic lava contains dissolved gases when it suddenly erupts onto the earth’s surface, the sudden reduction in pressure releases the gases which quickly form bubbles that make their way to the top of the flow. The eucrite, Ibitira, one of the few unbrecciated eucrites known, shows a remarkable vesicular texture (fig. 4), similar to that seen in a terrestrial basalt lava flow as that just described. Microscopically, the resemblance of most eucrites to terrestrial basalts is also most striking (fig. 5a and b). Fig. 5. Thin section photomicrographs in transmitted light under crossed polars of four typical eucrites (basaltic achondrites) (after Krot et al. 2005; McSween et al. 2011).

(a) The unequilibrated noncumulate eucrite Pasamonte, showing the typical basaltic texture of plagioclase (light) and pyroxene (colored). (Click image for larger view.) (b) The metamorphosed (equilibrated) noncumulate eucrite Ibitira, showing a recrystallized texture with plagioclase (white) and pyroxene (colored), with the round, dark areas in the center, bottom, and left being vesicles. (Click image for larger view.)

(c) The cumulate eucrite Serra de Magé, consisting of large crystals of plagioclase (lighter material with straight twin lamellae) and mostly orthopyroxene with complex augite exsolution lamellae (darker material with irregular, sometimes worm-like exsolution lamellae). (Click image for larger view.)

(d) The cumulate eucrite Moore County, consisting of large crystals of plagioclase (lighter material with straight twin lamellae) and colorful abundant orthopyroxene (with occasional exsolution lamellae) (scale bar is 2.5mm [0.09in]).

Mineralogically, the eucrites are quite simple. They consist almost entirely of plagioclase (30–50%) and clinopyroxene (40– 60%), the clinopyroxene usually dominating by 10–20%. The plagioclase in eucrites is calcic, being primarily anorthite with some bytownite, that is, within the range An 75-95, and igneous zoning is commonly preserved. The clinopyroxene is low-Ca pigeonite, with a composition that varies widely from specimen to specimen, and even within a given specimen. A typical pyroxene composition (wollastonite-enstatite-ferrosilite) in mole percent might be Wo1-25 En42-48 Fs43-52. Minor minerals include chromite (FeCr2O4), Fe-Ni metal, ilmenite (FeTiO3) and troilite (FeS) as opaque minerals, orthopyroxene, and polymorphs of silica—quartz, tridymite, and cristobalite.Eucrites are subdivided into three major subclasses—the noncumulate eucrites (basaltic eucrites), the cumulate eucrites (cumulate gabbros), and the polymict eucrites (polymict breccias of basaltic and cumulate eucrites) (Krot et al. 2005; Mittlefehldt 2005).Noncumulate (basaltic) eucrites are mostly fragmental breccias of fine to medium grained, subophitic to ophitic basalts that are postulated to have formed originally as quickly cooled surface lava flows. They are known as unequilibrated, unmetamorphosed or least-metamorphosed, noncumulate eucrites (such as Pasamonte—see fig. 5a), and are composed of pigeonite and plagioclase, with minor silica, ilmenite, and chromite, and accessory phosphates, troilite, Fe-Ni metal, fayalitic olivine, zircon, and baddeleyite. As a result of their apparent fast cooling their pyroxenes (pigeonite of Mg# ~70–20) are zoned, and exsolution lamellae are only visible by TEM. However, most noncumulate eucrites appear to have been subsequently metamorphosed, and are thus known as metamorphosed or equilibrated noncumulate eucrites (such as Juvinas, Stannern, and Ibitira—see fig. 5b). They are highly abundant and so are also collectively referred to as the ordinary eucrites. They are unbrecciated or monomict-brecciated, metamorphosed basalts and contain homogeneous low-Ca pigeonite (Mg# ~42–30) with fine exsolution lamellae of high-Ca pyroxene. The pyroxenes were originally ferroan pigeonite (~Wo7-15 En29-43 Fs48-58) which exsolved augite during metamorphism. In most eucrites, pyroxene Fe/Mg is uniform as a result of metamorphism, but original igneous zoning is preserved in very few. Plagioclase is calcic, with most in the range An75-93, and igneous zoning is commonly preserved. Cumulate eucrites are coarse-grained gabbros, many unbrecciated (such as Serra de Magé—see fig. 5c, and Moore County —see fig. 5d), composed of pigeonite, plagioclase, and minor chromite with silica, ilmenite, Fe-Ni metal, troilite, and phosphate as trace accessory phases. The original igneous pyroxene was pigeonite (~Wo7-16 En38-61 Fs32-46) which exsolved augite and, in some, inverted to orthopyroxene. They contain orthopyroxene inverted from low-Ca clinopyroxene (Mg# ~67– 58) and orthopyroxene inverted from pigeonite (Mg# ~57–45). Plagioclase is generally more calcic than that typical for basaltic eucrites, with most in the range An91-95. Polymict eucrites are polymict breccias consisting of fragmental and melt-matrix breccias mostly of eucritic material, but they also contain 50 4.5–6.5 element contents to produce a more definite Octahedrites O classification with meaningful distinct genetic groups that could represent different parent bodies (table 2). Coarsest 0gg 3.3–50 6.5–7.2 There are certain trace elements such as gallium (Ga), germanium (Ge), and iridium (Ir) that like Ni are Coarse Og 1.3–3.3 6.5–7.2 siderophile (or iron-loving), so they are used to subdivide the iron meteorites into distinct chemical Medium Orn 0.5–1.3 7.4–10.3 groups. Experiments have shown that because Ni tends to accumulate and concentrate in the liquid Fine Of 0.2–0.5 7.8–12.7 phase, then the first solid Fe-Ni alloy accumulating, Finest Off