ENCYCLOPAEDIA OF PETROLEUM SCIENCE AND ENGINEERING (Volume 14)
S.L. Sah
KALPAZ PUBLICATIONS
ENCYCLOPAeDIA Of' PeTROLEUM SCIENCE AND ENGINEERING
Left Blank
ENCYCLOPAEDIA OF PETROLEUM SCIENCE AND ENGINEERING (Volume 14)
Well Logs Interpretation, and Fundamentals of Palynology
S.L.Sah
IB PDBucmONS
KALPAZ PUBLICATIONS DELHI-11 0052
"This page is Intentionally Left Blank"
Encyclopaedia of Petroleum Science and Engineering
© S.L. Sah
ISBN: 978-81-7835-652-5
All rights reserved. No Part of this book may be reproduced in any manner without written permission. Published in 2008 in India by Kalpaz Publications C-30, Satyawati Nagar, Delhi-110052 E-mail:
[email protected] Phone : 9212729499 Lasser Type Setting by: Quick Media, Delhi Printed at : Singhal Print Media, Delhi
"This page is Intentionally Left Blank"
Dedicated to the Geophysicists, Geologists, Engineers, Scientists, Universities, Organisations, Teachers, Students, and other working in different disciplines ofpetroleum science and engineering
Left Blank
(CONTENTS ) Preface
11
1.
Well Logs Interpretation
15
2.
Fundamentals of Pleontology
101
3. Appendices
Appendix-B: Biological Evolution
241 245
Appendix-C: National Oil CompanyONGC (India)
265
Appendix-D: Important Figures and Data India after 60 Years (1947 to 2007)
280
Appendix-A: Evolution of Species
Appendix-E: News in Focus India to Soon Have a Research Base in Arctic
288
Left Blank
PREFACE "We usually find oil in new pla..
. I'~'-"'-' ~ -- -.~ ...-...... -. I H.. - .- .. :. "-
.
. ''5""
.
I
.__ •••.• -t.--~"
i~O
•
~..
R1
..
- - _. ~I!._ ~onlC
~C'
.
''':',
:.
-.- I-
--
. '-'
~ .
~~ ~H -. -. .
..
1--
. I
t;AS-
c: ..". ::
.,
-
.-
f:::
__ L-__ .
Fig. I. A compensated neutron and sonic log on the Louisiana Gulf Coast showing gas sands (Courtesy Schlumberger).
~
-J .
18
Encyclopaedia of Petroleum Science and Engineering
and the acoustic is in travel time. In some of the water zones there is an apparent gas separation. Advanced Gas Diction
Distinguishing between gas bearing and oil bearing reservoirs with resistivity logs is almost impossible. Although the gas bearing zones have lower water saturations than oil bearing zones the pore size variations usually marks our ability to separate the two on a pure resistivity or water saturation basis. Most gas detection today is done with the density and neutron log. Other porosity log combinations are sometimes used but are usually more difficult to analyze. The acoustic log generally is not influenced by gas when the formations are well consolidated or compacted. This includes essentially all carbonates, cements and consolidated sandstones and unconsolidated sandstones that are deeply buried and under normal net overburden stress. Normal overburden pressures are those where the pore (fluid) pressure is in the 0.433 to 0.465 psilft range. Values higher than that are considered abnormally pressured. . Gas effects on the acoustic log show up as increases in travel time (porosity calculated). The changes are apparently not related to the volume of gas (gas saturation) as the influences appear on the logs to be sharp and significant. There is little difference between 85 percent gas saturation and 60 percent gas saturation on the travel time measured. The gas effect appears to more influenced by the formation consolidation or compaction than by the gas saturation. In modestly uncompacted formations, where shale travel time is in the 100 to 125 1-1 seclft range the porosity can be corrected using the following equation:
;!
g
. ! " ;.'
I' .... ····I·!··I.············ ' , I
l;'
•
: ! ,
.
-.--
I
....... - ..................
~
. . ..
i
;0
I
, I
'
~s
Fig. 12. An overlay of neutron porosity and dielectric constant to show hydrocarbon zones.
is less than 10 ohm metres the DCL has troubles and when the resistivity drops below 5 ohm metres the dielectric constant will not be calculated. These dielectric logging systems are probably only qualitative below a porosity of 15 percent. Qualitatively the DCL appears to be a good overlay for the neutron log. The neutron log is looking at total water plus oil while the DCL is looking at water. In an oil saturated zone the neutron will round high and the DCL will record low. In water zones they should agree. Fig. 12 shows a computer overlay of a neutron and DCL.
31
Well Logs Interpretation Dual Porosity Systems
Often in carbonate fonnations there are two porosity system existing in the same rock. There is the matrix porosity which is the intergranular porosity. This porosity exists between the small grains. Also existing in many carbonates is the vuggy porosity. This can be solution cavities, moldic, secondary or big holes that supplies the permeability for the rock. In a hydrocarbon bearing reservoir, the oil or gas is usually in the vuggy porosity and sometimes in the intra-granular (matrix) porosity. In carbonates the matrix porosity concept may be expanded to include micro-porosity. This microporosity has an irreducible water saturation in the 100 percent range. The idea is to separate the water saturation that is associated with the very small pores and if often not a factor in determining if the well will produce hydrocarbons or water, from the water saturation in the large pores that is directly related to fonnation permeability and type of production. The relationship between these two different water saturations can be related by t!le following equation: Sw = VSwv + (1 - V) Swm
Sw
...(1)
total water saturation for the total rock
Swv
water saturation in the vugs or equivalents
Swm
water saturation in the matrix
V
fraction of pore space represented by the vugs.
Swv is the water saturation related to what will be produced, water or oil, and Swm is the immobile water tied up by capillary pressure. The extreme in this case would be a fractured rock. If the matrix is 4.5 percent porosity and the fractures are 1 percent porosity the water saturation could be not lower than 80 percent for this conditions. This would make the identification of a reservoir from logs very difficult. This problem can be solved by multiple porosity systems. The major problem with this technique is the obtaining of data to put into equation (1). Pyrite in the rocks results in a unique problem in well log interpretation. pnder nonnal conditions the conduction of electricity through the rocKs is via ionic conduction, i.e., ions actually result in the passage of curren~ With pyrite, which is a metal, the conduction is via electrons. !
32
Encyclopaedia of Petroleum Science and Engineering
The influence of pyrite on the resistivity measurement is greater using high frequency electrical current, like the induction logs, than on low frequency logs such as the old electrical logs. The formations with lower Rw have a greater response to pyrite than the formations with higher ~. The low frequency measurements such as LLd have essentially no pyrite response at low pyrite concentrations. If the pyrite is continuous as a thin layer the influence will be much greater and will show up as a low resistivity thin bed. The induction log, in the case of a thin continuous bed of pyrite will show a greater thickness than the focussed resistivity logs. This is due to shoulder bed resistivity effects. The density log is made almost unusable by the existence of pyrite in the rocks. Pyrite has an apparent density of 4.99 gm/cc. This makes for a reduction in calculated porosity of 1.4 porosity percent for every 1 percent of pyrite in the formation. Pyrite can be identified with the litho-density log (LDT) because it has a Pe of 17. Additionally pyrite influences the density log because of its significant photoelectric effect. The short spacing part of the measurement is more influenced than the longer spacing and thus the correction can be distorted. The influence of pyrite on the neutron logs depends upon the type of neutron log. Epithermal neutron logs should have little to no influence on the recorded porosity. 10 percent pyrite should show up as less than half porosity percent reduction to the real porosity. The influence on thermal neutron logs is much larger as iron is a significant thermal neutron absorber. At 10 percent pyrite the porosity has been increased by 3 to 4 porosity percent. At 30 percent pyrite the increased porosity on the neutron log is a total of 5 to 6 percent increase in porosity the influence of pyrite on the porosity derived from a density neutron crossplot is to create a crossplot porosity less than the actual porosity. A straight neutron porosity (CNL) would be closer than the crossplot porosity. The matrix travel time for pyrite is 67 microsecondlft (Clavier et. al., 1976). 10 percent pyrite would put the porosity off 1 percent. The pulsed neutron capture logs are very sensitive to pyrite due to the significant cross-section of iron. The matrix cross section of pyrite is 90 cu versus 10 for sand. Dispersed pyrite has no influence on the SP but continuou:; pyrite in a zone will cause a positive shift on the SP. Pyrite has no influence on the gamma ray log. Gas effects on both the density and neutron will reduce the apparent pyrite influences as gas effects are opposite to pyrite effects. A common philosophy is that the core porosities may be used to calibrate the porosity log to obtain better values. This mayor may not be true. Plug core analysis is not free from problems either. If the core is not homogenous, the plug core data will be optimistic. Plugs, on a per foot basis, represent a little more than 1 percent of\the volume of the
Well Logs Interpretation
33
core from which they were taken. Matching core and log porosities takes a little fmesse. We must match the depths, compensate for missing core and than match the porosities. A core gamma often helps. Correlating of log and core porosities may be performed by using digitized data or trend data that has been high graded. For the digitized correlation the log and the core data must be digitized at the same depth interval. Usually the log is digitized on a foot by foot basis. The core is also digitized in the same manner. If the core is not on a foot by foot basis, it must be converted. Once we get the core and log data digitized we can either overlay the core data on the log, after we have depth corrected the core data. Since the density and neutron log have a vertical resolutions of between two and three feet a three foot filter is usually applied to the core data to smooth it. The key to how good the filter is how good the core data tracks the log data. A fmer digitizing interval than 1 foot would increase the flexibility of choosing length of the filter and weights. Different filters apply for different logs as the vertical resolution of the density and neutron logs is not only a function of the source to detector spacing but also the logging speed and time constant used. Filtering data for correlations using core data and the acoustic log is much simplier. The acoustic log vertical resolution is defined by the receiver to receiver spacing (usually 2 feet) and the log averages linearly. Thus we usually, for a two foot receiver to receiver spacing, apply a two foot filter that is linear, e.g., 1 : 1. Most of the correlations between core and log porosity can be done easier and quicker by high grading the data optically taking into account the resolution of the tools and the statistical scatter. It is also less expensive. The key to good core log calibrations is the original depth correlations between the core and logs. If these are not good the whole exercise is irrelevant. Electromagnetic Propagation Tool (EPT) Log The electromagnetic propagation tool which Schlumberger runs measures the travel time of the electromagnetic wave as it passed by the two receivers (or antennas). It operates at 1.1 GHz. The pad containing the two receivers and transmitters is forced against the side the borehole as shown in Fig. 13. The path through the mudcake does not influence the measurement as long as the mudcake is less than 3/8 inch thick. Propagation time is related to dielectric constant. Print Table 1 here shows dielectric and equivalent propagation travel times. The two are closely related. The non-computer output for the ETP is porosity which should be water filled. The equation is given as :
34
Encyclopaedia of Petroleum Science and Engineering Table 1 Detectric versus propagation times (after Wharton et aL, 1980) (at 1.1 GHz)
I'r
Mineral
Sandstone Dolomite Limestone Anhydrite Dry Colloids* Halite* Gypsum* Petroleum Shale Fresh Water at 25°C
=
I'II0
lpt
4.65 6.8 7.5-9.2 635 5.76 5.6-635 4.16 2.0-2.4 5-25 783
nanosecim
7.2 8.7 9.1-10.2 8.4 8.0 7.9-8.4 6.8 4.7-5.2 7.45-16.6 29.5
*Values estimated from published literature. BOREHOLE flUID
•
NONINVADE1l ZONE
ENERGY 'ATH IN fORMATION UPPER IJlRA Y
EIIERGY II( MUoc.w
,
BACKUP t - - - - - {
ARM
MUOCAXE
Fig. 13. Schematic of the EPT tool (Courtesy Wharton et. al.).
Well Logs Interpretation
..
;t z
"'S ~
g
. Q
e 0 IX
Fig. 14. An EPT log example with computer processed results (After Wharton et. aI., 1980).
35
36
Encyclopaedia of Petroleum Science and Engineering Tpo - tPnl t pwo - tpm
where, propagation travel time obtained from the log propagation travel time obtained from solid matrix tpwo propagation travel time obtained from the water in the pores. Fig. 14 shows an example of the EPT combined with other logs. Zone A is gas bearing, zone B contains light oil, while zones C, D and E are essentially water saturated. Empty Hole Log Interpretation Empty holes are filled with gas at the time of logging. They have been either air or gas drilled or have been drilled with cable tool rigs. In empty hole log interpretation we are dealing with non-permeable formations and formation that produce gas. The logging program is limited to the density, neutron, gamma ray, caliper and induction resistivity logs. The other logs do not work in this environment because the gas in the borehole will not conduct electricity or acoustic waves effectively. Even the neutron logs are somewhat limited in that the CNL's are either not calibrated for gas filled holes or the tools require a neutron moderator for them to work properly. So in empty holes the neutron logs are either sidewall neutron logs or old conventional "uncalibrated type" neutron logs that output in cps, inches of deflection, API units or other units. In empty boreholes the density log must also be watched as often the sandstone formationscave badly when being drilled with air or gas. The three major logs are the density, neutron and resistivity. The density log is the source of porosity. Since the formations of interest contain both water and gas and the density log is investigating the uncontaminated virgin zone (because of no invasion), the interpretation requires some fmesse. The gas is a very low pressure because there is only gas in the borehole. The gas is assumed to have a zero density. Since gas at low pressure has a Z fA ratio significant different than the normal water filling the pores a correction must be made. This correction is approximately: P b = 0.9353 Plog +0.1747 ...(1) This correction is close enough to use for sandstones, limestones and dolomites and must be used to correct the log values of density to the "true" formation density. The neutron log responds to only the water in the formation unless the porosity is relatively high. The existence of significant quantities of gas in a formation will cause the neutron log to read too low because of the change in density of the formation. This has been called excavation effect by Schlumberger. Fig. 15 shows a plot Tpo tpm
37
Well Logs Interpretation
of excavation effect versus water saturation. At low porosities the influence is only around I porosity percent on the neutron log but reaches to 6 porosity percent at porosities of 30 percent and water saturations in the 50 percent range. It tends to increase the calculated porosity and decreases the gas saturation, and decreases the total gas in place. Since the neutron responds primarily to the liquid saturation it is used to determine the liquid saturation by the following equation: 8 --DOLOMITE -._.- LIMESTONE - - - SANDSTONE
C)
o...J Z
~
!:; '"z
e g ~
40
80
I
I
Water Saturation (Sw%) ~ _4L-__J -__-L__~L__ _~_ _-L__~____~__~__~__~
6~
Nex
= K(2 ~2 Sw
+ .04 ~)(1-Sw)
where K - 1 for 55, 1. 046 for 1s', 1.173 for dol.
Fig. 15. Excavation effect correction (Courtesy Schlumberger).
S
= fiq
~N ~
... (2)
Where the liquid saturation is the ratio of neutron porosity, corrected for excavation effect if necessary, to actual porosity. The induction resistivity log responds only to the water filled porosity. With the density neutron combination we can determine porosity and liquid saturation. If no oil is present, this liquid saturation is then the water saturation. To do this, we can either the equations or the chart shown as Fig. 16. This figure includes the density log correction for ZIA effects but not excavation effects on the neutron log because the latter is small for low porosities. Using the equations we first use equation (1) to obtain with density from the log density. Then, assuming the fluid density is equal to ~J~ and the gas density is zero, we have: ~
=
Pma -Pb +~N
...(3)
38
Encyclopaedia of Petroleum Science and Engineering POROSITY AND GAS SATURATION IN EMPTY HOLES DENSITY AND HYDROGEN INDEX OF THE GAS ASSUMED TO BE ZERO
Use Onl'l If no
Shale
IS
----
6
8
01;
~5
14
12
u;~
!
~~ 16
&' ~
18
16
20 .... u :>- 22
!oJ
24 ...;.:.. . .c.
,.-.
' - ' f..·- -:. .... '"
26
-;;
...
E 265
->-
iii 275 z w 280 0
z 285 1 4>1 is recorded in a continuous mode. A comparison of porosity from the density log or crossplot porosity with 4>1 will indicate the liquid bound to the formation. The mud is treated with a magnetite slurry before logging with an NML. This causes the mud signal to decay very quickly and thus not influence the measurement. Fig. 24 shows an example of 4>1 from an NML and a set of conventional openhole logs. The 4>1 is always less than the porosities indicated by the other logs. These logs are from the Texas Gulf Coast and thus are in essentially sandstone and shale sequences (Herrick et. at., 1979). Since the 4>/is related to the surface area of the rock it is expected that the determination of permeability could be better. Gas will show up as a lower 4>1 due to the lack of hydrogen. RESISTIVITY SP
.2
LL8
Ii 12mV
,
~
---~",
Z
3
4
Fig. 24. An example of dual induction, porosity and NML logs (After Herrick et. aI., 1978).
An additional measurement that can be made with the NML is TI • Although TI and ckf can be measured more accurately fi-om a stationary mode they are also both obtainable (with reduced accuracy) from the continuous mode. T2 is the bulk relaxation time of the liquid in the pore
Well Logs Interpretation
49
spaces. T, is the relaxation time of the complete system, i.e., bulk liquid, adsorbed liquids and anything else. This can be measured as the total energy needed to polarize the material or the total energy given off during relation. Bulk relaxation times are thus longer than T, because of the short relaxation times of protons in solids or bound to surfaces. T, is also influenced by the coexistence of oil and mud filtrate when the mud filtrate has a different T,. See Fig. 25. The hydrocarbon looks like it influences (a)
· ...... : .. ,- :----'~~~~~3;tt!:tt==l ."t+:----= , · .. ~ .•.... ·-Fqrmalion: . ',-,-.'ffi"".·~'-~ · .. +- .. ~- .... ~ of Tl"2.000 MS-......+'ffif-':---J - •••••• -
,
J,..1. ••
'
, j 1LV~
-::
I
-
=-:=~
: : 1.. - ••
"
',I
:
I
Time (millisecs) ms
(b)
Time
ms
Fig. 25. Tl measurements: (a) for an oil zone, and (b) for a water zone (After Collidge, 1962)
the T, by increasing the surface area. Fig. 26 shows the influence of water saturation versus hydrocarbon (decane) saturation on T, versus mercury injection pressure (which relates to pore size). The higher the mercury injection (capillary) pressure the smaller the pore size. The porous media is porcelain samples. Residual oil saturation has also be determined using the NML. Residual oil saturation is needed for enhanced oil recovery
50
Encyclopaedia of Petroleum Science and Engineering
WERCuA, INJECTlON PRESSURE AT 5O'Y. SATURATION.
,.i.
Fig. 26. Relationship between Tl and Capillary pressure.
methods. The mud is treated so that it has a very short relaxation time. Thus the only signal comes from the oil and the FFI reflects only the residual oil and not the mud filtrate. For this to work invasion must be efficient and greater than about 6 inches. Porosity and Lithology Determination
The conventinal density-neutron and acoustic-neutron crossplots assume that the rock is composed of two minerals. In mathematical terms the solution is one of three equations and three unknowns. One of these unknowns is porosity. These conventional crossplots can be used singularly or in combination. Fig. 27. This crossplots for the densityCNL for the appropriate fluid density assume a two minerals composition of the rock. In most cases the porosity obtained is good. We discuss only relatively cleans rocks filled with liquid. Since both the neutron and density log respond to density, if we adopt the theory that as the points on this chart move to the lower right hand corner (they move in a southeast direction) the matrix rocks have increased density. Then the lines labeled sandstone, limestone and dolomite are not lithology lines but lines of rocks with matrix densities of2.65, 2.71 and 2.87. A sandstone with a heavy quartz matrix, and there are a significant number, will plot towards or on the limestone line. A sandstone with anhydrite or dolomite cement will also leave the sandstone line and more towards the dolomite line depending upon the fraction of cementing material present. For example, a sandstone with significant amounts of ironstone will plot below the limestone line. The porosity read from the chart will be about right but the lithology cannot be read off the labeled lines.
51
Well Logs Interpretation '9~---r----r----l~I--~~--~--~-:-----'~~~=_~_-'~~~-_-:-':~.~
20r---+---~---4----~--+--'---"-~'----=-~~'--~----~'~~~----:~~nt-
~~:.~ ~~ ~=~~40 .. --. y-:-:~ 7~' 2.1~-:-:-"N"'~.14>. :!~;:--t-~--:-~r==t=7-t=~~:=i' . ~ I : ,,~~~..., ::=-="IHZ T ~3~ 'tC~",-
2.2
... _ .: - -P£'- - -
u
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.V" "'- .. --l;L:.:.:..:~:-:. -- .. H~ ~
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.
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.w
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. "-'bl'--' - ....--. 1---.
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.. ..=... ... Ii... .. ..... 0
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./
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llanvirn
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-----
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« fu.;;;;;- -----
0 c< 0
----'I;M;;-ed:::;;:ina=--L....J-O----;l-=o=we-:r:-1 Stlurian
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Cayugan
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:;;
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---- ----- ---I Caerfai
Ta,:oman
_ - - L ______ _
Fig. 18. Stratigraphic units used for lower Paleozoic systems in Europe and North America (After Tschudy and Scott, 1969).
fossiliferous beds of Cambrian age. Diversification of the plant-microfossil assemblages anticipates this faunal change. Fig. 19 shows the more common and simple types that occur in both the Proterozoic and Cambrian. Simple sporelike forms, commonly adpressed in irregular groups, occur in deposits as young as Ordovician. Microfossils of quite a different and more distinctive type, many of which are bilaterally
138
Encyclopaedia of Petroleum Science and Engineering
4
16
crj 19
0
20
22
Fig. 19. Acritarches from upper Precambrian and lower Paleozoic deposits (After Timofeyeu, 1959).
139
Fundamentals of Palynology
symmetrical, occur in the Ischorian (Middle Cambrian) beds and above. See Fig. 20. The spheroidal types (35 to 45), no doubt are acritarchs or
2
· O i:
;
-.. "~ 9
Fig. 20. Diacrodioid palynomorphs and acritarchs.
140
Encyclopaedia of Petroleum Science and Engineering
"hystrichs" that are widely distributed in the middle as well as lower Paleozoic. The bilateral symmetry shown by SOIne' of the sporelike microfossils of early Paleozoic assemblages is a most striking indication of floristic differentiation. The diacrodioid fossils commonly are compressed to form two accurate folds, which must be prominent microscopic features. A defInite gametophytic polarity with a functional trilete suture would be a more reliable indication of the existence ofland plants. The palynomorphs of the early and middle Paleozoic have usually been reported as hystrichosphaerids or as acritarchs. Acritarchs offer perplexing taxonomical problems. The most fundamental question concerning these microfossils relates in evaluation of the degree of polyphyleticism within the group. No doubt a great deal of the similarity of appearance reflects a universal biologic application of principles governing size and form and dissemination. For purposes 9ftexonomic assignment it may be necessary to emphasize and attach more signillcance to incidental features and minor resemblances than seems, on casual inspection, reasonable. Morphologic terminology may be used either in the sense of functional analogy or in the sense of homology. It seems doubtful that these supragenetic taxa can be regarded as having formal states in taxonomy because an all-important functional biologic justifIcation appears to be lacking for each of them. They represent arbitrary groups of genera. The group proposed can probably provide a useful artifIcial basis for identifIcation. Illustrations of specimens assigned to various genera that exemplify these morphologic groups are shows in Fig. 21. The authors who proposed these groupings of acritarchs agree that many of the rather similar microfossils in Mesozoic and Tertiary deposits are referable to the Dinophyceae. The abundant bilateral types of acritarchs that characterize Middle and Upper Cambrian and Tremadoc appear to be much diminised or lacking in younger deposits. Simple, thinwalled, spheroidal types, known as leiospheres, become abundant in the Upper Ordovician, Silurian, and Devonian. The smooth-walled acritarchs with a few hollow, elongate appendages have been studied by Downie (1963) from the Wenlock Shale. See Fig. 22. Downie reported a more or less progressive change in the acritarch populations throughout the Wenlock sequence. A fIrst attempt at derming stratigraphic distribution of acritarch general was provided by Eisenach (1963a), who simply listed ranges. Tasmanites was defIned and named by Newton in 1875. Characteristic disseminules of the type species make up a large proportion of the marine
Fundamentals of Palynology
141
~
Q
~
J ACANTHOMJRPH
2
SPHAEROMORPH
4 HERKOMORPH 5 PTEROMORPH NETROI>DRPH 9
7 POLYGONOMORPH
·'-:· 63 \
. O
;,
6 PRr3MATOMORPH
-~ . ~
~····~··
.. -...... ...
8
...
':
OOMORPH
-~
10 DISPHAEROMORPH
11 PLATYMORffi
DINETROI>DRPH
Fig. 21. Acritarch microfossils, representative of morphologic groups (After Tschudy and Scott, \969).
black shale of Permian age in the Mersey Valley of Tasmania. Solid deposits of the Tasmanites disseminules from Alaska have been reported. Recognition of Tasmanites as a planktonic alga suggests that such pure tasmanite deposits accumulated from algal blooms. The fossil disseminules of Tasmanites is as cysts of members of the class Prasinophyceae. Pachysphaera cysts develop from motile swarmers and may be as small as 10 microns in diameter. The great range of size in Tasmanites, as in the cysts of Pachysphaera, is a result of ontogeny and normal growth. Differences in micellar organization may make the cysts ofTasmanites more anisotropic than spores of higher plants when viewed by means of polarized light. Some microfossils assemblages include an abundance ofTasmanites cysts that are split into two lenticular segments. The time range of the Tasmanaceae is Ordovician and younger according to Downie and Sarjeant (1967). Phyletic antiquity implies a corresponding genetic isolation. Fossil evidence seems to support the identification of these plants as a separate class of green algae.
142
Encyclopaedia of Petroleum Science and Engineering
,::..
2
'r":;
~
(
':,,"
J
.JJj"
)(
"
~~8~.
Fig. 22. Silurian and Devonian acritarchs (After Tschudy and Scott, 1969). Fossil Plant (Angiosperm History) Angiospenns have dominated the land flora of the earth since midCretaceous time. The angiosperm-fossil record, which consists mostly of leaves, is the most extensive from the standpoint of numbers of specimens of any vascular-plant group. The oldest known plants that can reasonably be called angiospenns are Sanmiguelia, the palmlike plant from the Late Triassic, and Furcula, from the Rhaetic. The remains consists only of leaf impressions and a few fragmentary stem
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casts, though some cuticle is retained in Furcula. Angiosperms did undergo remarkable spread and diversity during Cretaceous time. 40 families appeared in the Dakota Sandstone flora of the early Late Cretaceous. Flowering plants had evolved rapidly during the Early Cretaceous interval. At least 80 percent of the living angiosperm families have fossil records of sorts. A considerable number are limited to remains in Pleistocene peat deposits, but more than half of the extant families have Tertiary records, and a considerable member can be traced into the Cretaceous. Leaf impressions and silicified trunks of palms occur in a number of Upper Cretaceous localities. The list of angiosperm families is continually expanding as investigations on cuticles and pollen are completed and published, and as old collections are reexamined and analyzed by modern techniques. For additional information consult Engler (1964). Partial list of Cretaceous Angiosperm Families is give below: Palmae
Ericaceae
Meliaceae
Rosaceae
Aceraceae
Fagaceae
Menispermaceae
Salicaceae
Annonaceae
Guttiferae
Moraceae
Sapindaceae
Araliaceae
Hamamelidaceae
Myricaceae
Starculiaceae
Betulaceae
Icacinaceae
Nyrnphaeaceae
Tiliaceae
Celastraceae
Lauraceae
Oleaceae
Ulmaceae
Plantanaceae
Vitaceae
Cercidiphyllaceae Leguminosae Comaceae
Magnoliaceae
Proteaceae
Fossil Plant Record
Fossil plants occur mostly in sedimentary rocks. Marine deposits may contain algae and other forms of sea life, but terrestrial vegetation is preserved in greatest abundance in sediments laid down under nonmarine conditions. Wherever coal seams occur fossil plants are likely to be found. Volcanic activity provides ideal condItions for preservation of plants in large numbers. Lava flows dam streams and form fresh-water lakes that quickly become filled with erosion products of loosely consolidated ash deposits. Man of the best known Tertiary floras were preserved under such circumstances, e.g., Florissant in Colorado. All parts of the plant body may be preserved as fossils, but they are usually disconnected from each other, e.g., leaves, pollen, seeds, or stems. The organs preserved in the greatest quantities are made up of tissues with
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the greatest resistance to decay or abrasion, e.g., woody tissues, hard nuts, seeds, cutinized parts such as spores, pollen grains, and leaves of coriaceous texture. Plants are fossilized in several ways. The most familiar types are impressions, which are merely imprints left in soft sediments. In compressions or compactions the plant parts are squeezed flat between layers of compacted sediments but under conditions that arrest decay. In casts a cavity left by decay of a plant part is secondarily filled. In petrifications some or all the tissue structure is retained by infiltration with various minerals. The process of petrification is responsible for the preservation of countless tree trunks found in many parts of the world, ranging in age from the Devonian to the Recent. Coal balls, carbonate, and pyritic nodular masses sometimes found in coal seams or roof shales. Petrifications are of special value in paleobotanical research because they supply information not revealed in other types of fossils on the internal structure of extinct plants. Changes do take place in the chemical composition of plants during petrification. Analyses of petrified wood have revealed the persistence of cellulose and lignin, though in proportions that are somewhat different from those found in living woods. Fossil Plant Record (In Different Eras) Archeozoic Era has a dim plant record. The fossil record fails to enlighten us as to when, where, or how life came into existence. Plants capable of photosynthesis and the consequent release of free oxgen into the air had certainly come into existence by middle Precambrian time roughly 2.3 billion years ago. At about this time the oldest fossilized organisms were alive. From the middle Huronian Gunflint chest Barghoom and Tyler (1965) found minute objects that resemble colonies of bluegreen algae and filamentous objects with attached spores that seem to represent fungi. Most of the Evidence of life during the Archeozoic is indirect, in the form of precipitates of calcium, iron or sulfur. In the Belt series of Montana large and distinctly formed reeflike structures show a close resemblance to similar ones formed by blue-green algae of the present day. In the Paleozoic Era the development ofland floras is started. Remains of higher plants are scare in the predominantly marine rocks of the earlier half of the Paleozoic Era. There is ample evidence of both calcareous and noncalcareous algae in the Cambrian seas. An axis bearing small, sinlple, leaflike appendages from the Middle Cambrian of Siberia was named Aldenophyton antiquissimum. Externally the plant resembles
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a herbaceous lycopod. 12 types of cutinized spores have warty exines and triradiate tetrad scars. They resemble some of the vascular plant spores found in Devonian and Carboniferous rocks. The Ordovician seas supported rich algae floras that supplied ample food for the many forms of invertebrates and primitive fishes that appeared during that time. The algal floras of the Ordovician seas persisted into the Silurian. An enigmatic plant that appeared in the Silurian was Prototaxites. The Middle Cambrian Aldanophyton is a vascular plant, the oldest plants of this category come from the Middle Silurian. In the Devonian exphasis shifts from the predominantly marine algal floras to land floras composed of vascular plants. The floras of the Lower and Middle Devonian were formerly referred to as the Psilophyton flora, and that of the Upper Devonian, as the Archaeopteris flora. The lycopods are especially well represented in the Middle Devonian by several genera. Upper Devonian floras contain a variety of lycopods. No objects definitely identified as seeds have been found in the Devonian. Floras evolved rapidly during the transition from the Devonian to the Mississippian Period, and the plants existed in the latter period in greater variety and abundance then in the rocks of the Devonian System. Several new lycopods appear in the Lower Mississipian. The oldest seed plants, the pteridbsperms, are found in rocks of the earliest Mississipian age. The Mississippian phase of the New Albany black shale contains a rather large flora represented mostly by small sterns and petiole fragments preserved in small phosphatic concretions. Plant remains are abundant in the Pennsylvanian rocks that represented deposition in swamps where coal was formed. In some places large quantities of plant material is preserved in coal balls, and these have yielded valuable information on the internal anatomy of the plants of that period. Pennsylvanian floras, early and late, are set apart from those of other periods by an abundance of arborescent lycopods such as Lepidodendron and Sigillaria, giant-sized members of the scouringrush group typified by Calamities, the low growing Sphenophyllum, true ferns and the fernlike Coenopteridales, seed ferns of the Lyginopteris and Medullosa types, and early fore-runners of the conifer class, the Cordaitales. Members of these groups are often preserved in profusion in the shales that overlie coal beds. Equisetites closely resembles and may have been virtually indistinguishable from a modem Equisetum. The Mississipian and Pennsylvanian Periods were for a long time referred to
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collectively as the Carboniferous because of the abundance of fernlike foliage in rocks of the two periods. A number of form genera had been created for the various kinds of fossil fernlike foliage, e.g., Pecopteris, Sphenopteris, Neuropteris, Mariopteris, and Alethopteris. They are distinguished from each other mainly by the form and venation pattern of the pinnules. Probably the largest and most diversified group of fernlike plants in the late Paleozoic floras was the Coenopteridales. The largest of the known late Paleozoic ferns was Psaronius, which appears in the Early Pennsylvanian and extends into the Early Permian. Several families are recognised among the Paleozoic pteridosperms, but the best established ones are the Lyginopteridaceae and the Medullosaceae. The Cordaitales constituted another group of seed-bearing plants of the late Palezoic coal-swamp forests. The Coniferales apparently date from the Pennsylvanian Period. Vast changes took place in the plant world during the Permian Period. The cold climate that had spread over much of the Southern Hemisphere began to extend its influence over the rest of the earth. The lowered temperatures were accompanied by aridity. The swamps dried up, and the lush vegetation that they supported disappeared. It was replaced by newly evolved forms with smaller, thick, heavily cutinized leaves. Only the groups that were able to modify themselves to the adverse conditions were able to survive, e.g., Gigantopteris, Callipteris, Tingia. The youngest Permian flora found in North America was described by White (1929). Glossopteris flora spread throughout the Southern Hemisphere during the latter part of the Paleozoic Era, occupying ancient Gondwana-land, and remnants of it are found in southern Africa, India, Australia, and South America. The Glossopteris flora characterizes the lower of the two divisions of the Gondwana group. It has a total thickness of 30,000 feet in India and other places in the Southern Hemisphere. The upper Gondwana flora is quite different from that of the lower series. No actual traces of the Glossopteris flora have been found in North America. The Mesozoic flora was initiated during the latter part of the Paleozoic Era. In the earliest Triassic the scouring-rush order is represented by Equisetites and Schizoneura. The principal lycopod is Pleuromeia, a plant more than a metre high that resembled a dwarf Sigillaria. Neuropteridium is the most characteristic fern genus, and a few fronds
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are referred to Zamites and Pterophyllum. Voltzia is the best known of the Early Triassic Coniferales. The most thoroughly studied Middle Triassic flora is the Ipswich flora of Queensland. It contains the probable pteridosperm Stenopteris, a few ferns identified as Cladophlebis and Dictyophyllum, and leaves resemble with the modem Ginkgo. The much richer Late Triassic flora contains Neocalamites, which is intermediate in size between Calamites and Equisetum, numerous pteridosperms, an abundance of cycadophytic foliage types, and conifers resembling Voltzia. The Rhaetic is sometimes regarded as uppermost Triassic. From the Rhaetic of Sweden comes Bjuvia simplex. Jurassic plants range from the Arctic to Antarctic and are especially abundant in eastern Asia, Siberia, Argentina, South Africa, India, Australia, Great Britain and Central Europe. Almost all Jurassic floras consist of ferns, cycads and cycadeoids, ginkgophytes, and conifers. A series of deltaic deposits known as the Oolite contain exceptionally well preserved foliage and fructifications of almost all of the plant groups known at that time. In Bihar in eastern India, the Rajmahal upper Gondwana series, which is believed to be of Late Jurassic age, contains plant similar to those found in Jurassic rocks elsewhere. A group of plants peculiar to this regions is the Pentoxylales. Several modem fern families are recognizable in the Jurassic. Among these are the Matoniaceae, Marattiaceae, Cyatheaceae, Osmundaceae, and Schizaeaceae. The Jurassic rocks are rich in remains of conifers. Sequoria first appears in rocks of this age in China. Typical Jurassic genera are Araucarites, Brachyphyllum, Pagiophyllum, and Podozamites. Silicified trunks of Cycadeoidea occur in Jurassic beds. Tempskya fern range from the Wealden to the Senonian, it seems to be confirmed to the middle part of the Cretaceous System. Weichselia fern possibly ranges into the Late Cretaceous. Two other ferns are knowltonella and Schizaeopsis from the early and late Early Cretaceous, respectively. The Cretaceous was an important period in the history of the plant kingdom. It was during this time that the ferns and gymnosperms surrendered to the flowering plants. Overlying the Lower Cretaceous Potomac group with its early angiosperms are the Raritan and Magothy Formations, which are assigned to the lower Upper Cretaceous. These have large floras that contain upto 60 percent angiosperms. The flora of the Dakota Sandstone contains 460 named species. 99 percent of these are angiosperms. All Late Cretaceous floras are dominated by angiosperms, and they consists largely of families in existence today. Even the ferns are modem. The
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plant fossils that are most commonly encountered in Upper Cretaceous rocks are leaves that resembles those of laurels, figs, oaks, and other broad-leaved trees of today in forests of moderately warm and wellwatered regions. Modem floras of the Cenozoic Era come after the Mesozoic flora. Warm climates extended into far northern latitudes during the Paleocene and Eocene Epoches. Palms thrived in southern Canada, and pines, birches, and willows grew in land areas now only 8 degree from the North Pole. One of the largest of the early Tertiary floras is the Wilcox flora. This floras ranges from Alabana to Texas and consists of several hundred species .that represent 180 genera and 82 families. It bears a close resemblance to the Recent flora of the Antilles and Central America. Legumes are the dominating elements in this flora, but there are numerous members of the Lauraceae, Araliaceae, Me1iaceae, Moraceae, and Palmaceae. The Green River flora of Wyoming, Colorado, and Utah contains abundant algal remains that must have originated in warm, shallow water. The Green river flora also contains cycads, conifers, palms, figs, sweet gums, laurels and oaks. For three centuries casts of seeds and dry indehiscent fruits have been collected in large numbers where they weather out of the Eocene London clay along the Thames below London and on the Island of Sheppey. The blocking of streams by flowing lava (between Late Cretaceous and Miocene) produced numerous freshwater lakes, which were in tum filled with falling ash and material freshly eroded from ash deposits. These lake beds contain the most extensive records of Tertiary floras known anywhere. Remains of the floras are the best indicators of Tertiary climates. They show the increase in warmth over northern latitudes. They also show the effect of proximity to ocean basins by revealing marked differences between inland and coastal floras at similar latitudes. Western American floras existed in North America upto Miocene or Pliocene time. Some of these floras are Ginkgo, Pseudolarix, Metasequoia, Ailanthus, Koelreuteria, Cercidiphyllum, Trapa, and Zelkova. Large floras of early to middle Oligocene age are preserved in the lake beds at Florissant in Colorado and in the Ruby valley in southwestern Montana, e.g., Metasequoia, Salix, Morns, Populus, Quercus, Mahonia, Carya, Zalkova, Sassafras, Persea, Cercis, and Sapindus. The effect of proximity to the sea is showd by the Weaverville flora in California. It is quite different, being a subtropical assemblage, as
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indicated by such genera as Taxodium, Nyssa, Tetracera, and Ficus. The late Oligocene or early Miocene Bridge Creek flora of the John Day valley reflects the return of slightly lower temperatures after the peak of the warmth. Miocene floras are rich in such genera as Acer, Alnus, Quercus, Populus, Salix, Prinuis, Picea, Platanus, Fagus, and Mahonia. The summers became drier and seasonal changes become more pronounced. Several genera such as Carpinus, Ulmus, Tilia, and Fagus persisted in the eastern half part of the continent. The cooling trend that culminated in the Pleistocene ice age continued to develop during the Pliocene. It was then that the Arctic tundras. Elevation of the Cascade range during late Miocene time reduced the rainfall to the eastward, thus initiating the desert environments of the Great Basin and adjoining areas. The last remaining link between Tertiary floras and those of the present are revealed to some extent by pollen and other plant remains preserved in peat bogs of Pleistocene and post-Pleistocene times. Fossil Plant (Time Scale)
The conventional eras and periods of geological time are based principally on major changes in faunas revealed in the rock succession. Proterozoic means the age of earlier animal life. Paleozoic in turns means the age of ancient animal life and Mesozic and Cenozoic mean middle and recent life, respectively. Plant kingdom establishes five eras but retains the periods of the conventional geological time. The oldest era, the Archeophytic, embraces the oldest known rocks up through the early Precambrian. It would include the oldest living things and the simple organs that evolved from them The succeeding era is the Eophytic, which extends from the later Precambrian into the Silurian. This could be called the algal age. Vascular plants, which might have been in existence during the latter part of the Eophytic era, first become recognizable as floras at about the middle of the Silurian, which marks the beginning of the Paleophytic era. This begins with the Upper Silurian and continues through the Lower Permian. Within it appeared the early land floras of the Devonian and the Mississippian, Pennsylvanian, and Early Permian floras that followed. By Late Permian time the spread of colder climates and the disappearance of the lush coal swamp forests is everywhere manifest, and this marks the beginning of the Mesophytic era, which extend to about the middle of the Cretaceous Period. Then floras marked by the dominance of angiosperms characterize the upper half of the
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Cretaceous Period, which represents the earliest phase of the Cenophytic era, or the era of modem flowering plants. The Cenophytic embraces the Upper Cretaceous and the Cenozoic of the standard sequence. The Mesophytic and Canophytic thus each began about half a period earlier than the conventional Mesozoic and Cenozoic, evidently due to the fact that plant evolution had preceded changes of corresponding magnitude in animals by approximately half a period. The stimulus to dinosaur evolution might have been major changes in floras during the Permian, just as mammalian evolution received a boost from the Late Cretaceous angiosperms.
Jurassic and Early Cretaceous PoDen and Spores Palynology shows that plant evolution was an eventful in the Jurassic and Early Cretaceous as in any other period of comparable duration. The marine stratigraphic succession is well correlated in Europe and in many other areas, and therefore dating of nonmarine successions by palynologic correlation can be particularly effective in these periods. Table 4 shows the stratigraphic divisions of the Jurassic and Early Cretaceous in Western Europe. Plant-microfossil assemblages of the Jurassic and Early Cretaceous reflect their provenance from a much more diverse group of gymnosperms from petridophytes to bryophytes. Of the gymnosperm representatives the bisaccates, when present, frequently predominate. More than 100 genera have been used for the many organ species described from this period. The most prominent type is classified as Cyathidites (Couper, 1958), which has a concavely triangular amb and simple long laesurae. Spores with a circular amb are found in compression ferns such as Todites williarnsoni. Other smooth spores with the laesurae enclosed within elevated lips are classified in Biretisporites, which has a uniform exim. See Fig. 23. One of the most difficult spores to identify is Calamospora mesozoica. Some smell, thick walled spores of the genus Stereisporites are believed to represent the Sphagnales. Osmundacidites was erected for granulate spores. Species of Pilosisporites are common in Lower Cretaceous rocks. Kuylisporites bears distally a number of crescentic pseudopores. Cyclosporites has a distal recticulum of highcrested muri with an unusual proximal radial arrangement of similar muri. Staplinisporites has radial and concentric distal muri and a distal polar thickening. Perhaps the most striking murornate spores fall in the genus Cicatricosisporites with distal and equatorial parallel muri. The smooth valvate spores are included in Matonisporites. Plicatella has parallel
Table-4 Stratigraphic Divisions of the Jurassic and Early Cretaceous in Western Europe Period
T Early Cretaceous
1
Jurassic
Age (Stage)
Definition ofBeginning of Division (Zone oj)
Notes
Albian Aptian Barremian Hauterivian Valanginian Berriasian
Leymeriella tardefurcata Prodeshayesites fissicostatus Paracrioceras strombecki Acanthodiscus radiatus Kilianella roubaudiana Berriasella boisseri (approximately)
Including upper and middle Purbeck beds
"Tithonian"
Gravesia spp., Taramelliceras lithographicum
Including lower Purbeck beds, Portland beds, upper and middle Kim meridge Clay
Kimmeridgian Oxfordian Callovian Bathonian Bajocian
Pictonia baylei Quenstedtoceras mariae Macrocephalites macrocephalus Zigzagiceras zigzag Leioceras opalinum
Including lower Kimmeridge Clay
Toarcian Pliensbachian Sinemurian Hettangian
Dactylioceras tenuicostatum Uptonia jamesoni Arietites bucklandi Psiloceras planorbis
Including French Aalenian Bajocian and Vesulian (sensu Arkell, 1956)
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:6
"
.,.
2J
Fig. 23. Smooth Azonotrilete Miospores (After Couper, 1958).
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regular equatorial and distal muri and also short radial equatorial appendages. Interradial crassitudes are clearly displayed by Gleicheniidites, which has a smooth exine. Cingutriletes and Taurocusporites are genera for spores with a circular ambo Forarninisporis includes granulate to verrucate species with a very narrow, sculptured cingulum. Contiginsporites shows a single distal set of parallel muri that coalesces with the cingulum. Spores with a cavate separation of exine layers are not common. Monolete fern spores are relatively rate in the Mesozoic, the most common being Marathisporites. Aequitriradites has a broad membraneous zona. Tsugaepollenites seems to be most appropriate genus. Bisaccate pollen grains form a most important element of Mesozoic assemblages. In the Jurassic there are records of the very large Abietinaepollenites dunrobinensis with a corpus length of about 100 microns. In the Early Cretaceous species of Parvisaccites became important stratigraphically. Monocolpate pollen is mostly unsculptured. The most surprising colpate grain is Eucommiidites. Calvatipollenites is monocolpate, with a finely clavate exine that become tectate. Throughout the Jurassic and most of the Early Cretaceous the small spherical monoporate Classopollis occurs in a large proportion of assemblages as is the dominant form in certain facies, e.g., Perinopollenites, and Elatides williarnsonii. Ararcariacites is a large thin, walled scabrate grain common in the Early and Mid-Jurassic. Dispersed megaspores have a mean diameter of over 200 microns and could in many cases be accommodated on morphographic ground in miospore taxa, e.g., azonate megaspores, zonate megaspores, barb ate megaspores, and pyrobolotrilete megaspores. All the spores of this group belonged to aquatic plants of which the main organs are unlikely to have been fossilized. They may have belonged to the fern family 'Marsiliaceae, although it contains no precise Recent parallels. Jurassic and Early Cretaceous (Distribution, Sequence, and Evolution of Floras) In Europe, there is a full rock succession, and, although much of it was of marine origin, there were always extensive islands and embayments with non-marine facies. The Lias a of Poland was deposited in such an embayment, and the assemblages have been described by Rogalska (1962). Similar assemblages from southern Sweden and other parts of Europe show a marked rise of Osmundacidites and the appearance of Eucommiidites. Classopollis becomes abundant and
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remains so for the rest of the Jurassic Period. The assemblages are not very different from those of the Rhaetian (Late Triassic) immediately below, although Ovalipollis and some other Triassic genera have disappeared. European assemblages from the stages Sinemurian to Toarcian are less well known and thus less distinctive, because of the effect of fairly widespread of marine transgression. Very large bisaccate grains appeared at this time in Britan, but not in Europe. Bajocian and Bathonian floras are well known from the classic area of Yorkshire, England. Numbers of Tsugaepollenites and Araucariacites increase rapidly, as do several species of Lycopodiumsporites. Among monosu1cates the large benettitalean types become less common than the small oval species. Callovian to Tithonian assemblages continue to be dominated by Classopollis, Tsugaepollenites, and Araucariacites. There is less variety in bisaccates, although these include some grains with a short, wide corpus. The assemblages of the fIrst from Early Cretaceous stages are marked by striking charges in the fern spores. Cicatricosisporites becomes universal, as do to a lesser degree Trilobosprites, Pilosisporites, and others. Aqequitriradites become numerous among the hilates, and Schizosporis retriculatus is a regular occurrence. Aptian and Albian assemblages are marked by a sharp increase in the Gleicheniidites and a decrease in Cicatricosisporites, Plicatalla, etc. Ephedripites becomes more common, and bisaccates appear with a clear resemblance to some Recent genera. Among megaspores the sudden diversifIcation of Arcellites and Pyrobolospora is striking. In northern temperate areas many assemblages have been described from Asia, but they are not very different from those in Europe. Cycadophytes would be more common in lower latitudes and coniferophytes more abundant further north. In the "tropics" Chlamydospermae such as Eucommiidites and also Classopollis predominate over saccate and monoporate conifer grains. In Australia (Southern Hemisphere) Cicatricosisporites is much less diverse, and Plicatella does not appear. Exesipollenites is an important element with Classopollis in the Early Jurassic. Polysaccate conifer grains are suddenly important in the Early Cretaceous. The Albian in Australia is characterized by the unusual Hoegisporis. The Jurassic and Early Cretaceous were periods of very varied selection for new types of spore and pollen apertures, some of which
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originated in Late Triassic time. The pollen apertures seem to culminate in the tricolpate type just before the Cenomanian age. Spore exine sculpture shows much greater variety than at any time since the Carboniferous, particularly in the Early Crataceous. Monosaccate pollen becomes much less important after the Triassic. The variety and size of the bisaccate conifer pollen decrease through the Jurassic, and the trend changes only with the sudden increase ofParvisaccites in the Barremian. Podocarpidites is rare through the Jurassic and into the Early Cretaceous. There are Early Cretaceous macrofossils ofPinites leaves and cones. Any evolution is not found in the small-grained nonsaccate gymnosperms represented by Spheripollenites and Inaperturopollenites, which are closely parallel pollen of some living trees. Monosulcites type of grain does persist unaltered to the present day in living cycads. Classopollis appears to provide one extreme of the logical development of all-sound germinal apertures by the zonosulcate method. Species ofEurommiidites are distinctly smaller in the Early Cretaceous than the type species in the Jurassic. Strongly sculptured fern spores is well illustrated by Bolkhovitina (1961). The exine sculpture pattern of angiosperm pollen become subsequently modified in more subtle ways. Many of hilate spores certainly represent bryophytes of which macrofossil evidence is unlikely to be found for preservational and paleoecological reasons. By their very nature fresh-water vascular plants are unlikely to have sufficient cuticle to favour reasonable preservation of macrofossils. Their requirements for distribution lead to the development of elaborate structures for floating, for entangling, for water seal against premature growth in their usually thick-walled spores. Throughout the Jurassic and Early Cretaceous magaspore "species" are much more numerous than the known heterosporous land plants. Late Cenozoic Palynology
Late Cenozoic floras can be compared with living plants on a more detailed taxonomic basis than can older floras. The large amount of detail available from late Cenozoic floras emphasizes considerations that are not usually as apparent in older assemblages. In many instances much could be learned from the comparison of modem pollen rain with late Tertiary pollen assemblages. The late Cenozoic includes the Miocene and Pliocene Epochs of the Tertiary Period and the Quaternary period. The Quaternary Period is comprised of the Pleistocene plus the Holocene Epochs. The best documented late Tertiary floras are from the middle
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and high latitudes of the Northern Hemisphere. Late Cenozoic floras differ from earlier ones. These characteristics of late Cenozoic floras are given below: 1. Decreasing diversity of flora.
2. A higher proportion of fossil-plant forms from late Cenozoic assemblages can be placed in living genera or species than can forms from early Cenozoic floras. 3. Pollen of certain families fIrst appearing or becoming abundant in the Neogene can be useful as indicators oflate Cenozoic age. The fIrst occurrence of pollen of Compositae is a stratigraphic marker for the late Oligocene or early Miocene all over the world. Also certain herbaceous as well as woody angiosperm are included in highly evolved families. 4. A large proportion of Neogene plants or their close relatives are now living near their Neogene sites of occurrence, but typically only a small proportion of such plants or their near relatives in Paleogene floras are now a part of the local flora. This characteristic is evident on both the generic and specifIc levels. 5. Unlike most of early Cenozoic age, late Cenozoic floras typically demonstrate marked provincialism Assemblages of post-middle Miocene age may differ widely within small areas; this is apparently the result of latitudinal and topographic differentiation during the late Cenozoic. Because of this differentiation the distances over which floras can be correlated are lessened for Pliocene and younger assemblages.
Late Cretaceous and Early Tertiary Palynology The Late Cretaceous began under conditions of major worldwide marine transgressions that reached maxima during Cenomanian-Turonian and Maestrichtian times. The transition from Albian to Cenomanian time saw the continued increase in flowering plants, with some decline in pteridophytes. The transgressions, regressions, and orogenies occurring over the whole internal coincide with extraordinary evolutionary developments in insects, flowering plants, and placental mammals. Reconstruction and interpretation of the floral world of Late Cretaceous time rests primarily on the evidence afforded by the study of leaf
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impressions. Here floras from Greenland, Western Europe, Siberia, Japan, China and North America have played prominent roles. The pattern of evolutionary change that occurred within the major groups of vascular plants during the transition from Early into Late Cretaceous time seems remarkably similar wherever floral successions have been studied. Fig. 24 gives the selected stratigraphic divisions of the Late Cretaceous European Stages
Sen.s Oligocene
U S. Gulf Coastal Ptam
Ch.ttian
(upper)
Rupelaan
(mIddle)
Lattorlian
Eocene
Priabonian
Jackson Stage
lutetl,"
Claiborne Group
Ypres,an
Wilcox Group
Spamaclan
Paleocene
Thanetl.n
Midway Group
Montian - Daman
.j
Maestrtchtian
Navarro Group
Campanian
Taylor Group
Jf - - - - - - - SantOnian
Upper Cretaceous
Austm Chalk
ConiaCian I-_T_uron_ian______ Cenomanian
Eagle Ford Shale
~----------~ Woodbine Formallon
Fig. 24. Selected stratigraphic divisions of the Late Cretaceous and early Tertiary (After Tschudy and Scott, 1969).
and early Tertiary. Newer palynological analysis of mid-Cretaceous sediments have yielded preliminary evidence that is not always concordant with the paleofloristic and paleoecological interpretations based on leaf floras. Comparisons of the plant microfossils and megafossils of the Perutzer, Dakota, and Raritan Formations will illustrate this point. The Perutzer flora of western Czechoslovakia consists of more than 230 species ofleaf, fruit, and seed remains. More recent stratigraphic assignments have suggested an age range from Aptian to Cenomanian for the Dakota Sandstone throughout the wide area of its development in western interior United States. A third well-known early Late Cretaceous assemblage is the Raritan flora of Eastern United States.On strong megafossil evidence, supported by some faunal evidence, the formation is outcrop is of Cenomanian age. In their study of eight Portuguese samples ranging in age from Aptian to Cenomanian Groot and Groot
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(1962b) recorded 46 species of spores and pollen of which some 31 species were of pteridophytic or gymnospermous affinities. Pteridophytes, especially ferns, tend to be well represented by trilete and monolete spores. Species of Trilobosporites, Pilosisporites, and the more bizarre schizaeaceous types known from Lower Cretaceous deposits are absent or rare. The widespread transgressions of the Cenomanian seas swelled to their maxima during the next Turonina Epoch. Turonian megafossil evidence, confirmed at least by Northern Hemisphere microfossil records, attests to the attainment of full dominance by the angiosperms and to a slow decline in the number of fern, cycadophyte, and conifer genera. See Fig. 25. Cretaceous and Tertiary palynological
70
60
~50
t
1
40
.
~
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~ 20 "-
10
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0
Fig. 25. Total fossil pollen and spore groups Lower Cretaceous-Pleistocene (After Cousminer, 1961).
studies from 1930 onward have tended to establish Central European sequences as standards for correlation purposes. Generic similarity may exist in widely separated Turonian assemblages across much of Eurasia and North America, but perhaps not south of the Tethyan geosyncline. The Northern Hemisphere Turonian plantmicrofossil record is distinguished from the Cenomanian record by two features : (1) the first
Fundamentals of Palynology
159
clear dominance of angiosperms over pteridophytes and gymnosperms, and (2) the prevalence of a morphological type of nonporolate dicotyledonous pollen of remarkable variety, whose many form genera are usually grouped under the morphologic category Normapolles Plug. Turonian Normapolles types, such as Monstruosipollis Krutzsch, Extratriporopollenites Pflug, and others, are characterized by complex, often protruding and vestibulate, pores. A general post-Turonian decline and extinction of inadaptive species after minor climatic deterioration during Coniacian-Santonian time may have accounted for the disappearance of some Normapolles types. See Fig. 26. The surviving 50
is. ::J 40
e
..'" r.t 30 .. (;
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.!!
20
"0 Q.
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10
0
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Normapolles-producing dicotyledonous plants presumably were ancestral to many of the modern dicot genera appearing in the oldest Tertiary. There is no paleobotanical evidence of widespread climatic or other ecological change occurring at the onset of the Senoninan and plant microfossils of the Northern Hemisphere reflect the continued diversification and migration of the now completely dominant angiosperms. Southern Hemisphere spore-pollen floras of similar age remained dominated by conifer pollen. Nothofagus and Proteacidites make their fIrst appearance in New Zealand during the early Senonian. The angiosperm component of the earliest Northern Hemisphere Senonian
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pollen floras remains characterized by Norrnapolles forms of uncertain botanical aflinities. Toward the close of the Santonian Epoch Norrnapolles types became associated with types displaying increasing morphological resemblances to pollen of modern plants. Late Senoninan pollen assemblages tend to show a mix character that is intermediate between Late Cretaceous and early Tertiary. Middle European floras of latest Cretaceous age reflect maximum evolutionary development of such Normapolles types as Oculopollis, Trudopollis, and Vacuopollis, in company with the first appearance of pollen indicating sapotacean, nyssacean, and palm affmities. The fern-rich early Senonian floras of South America show, by Maestrichtian time, a marked influx of palm pollen in association with a variety of dicotyledonous types, presaging the more modern, and typical South American, Tertiary flora. Western North American pollen floras of Senonian age appear to show an early attainment of a modern aspect. From late Senonian time onward the compositions of pollen floras show an increase in the number of types assignable to extent genera, and a rapidly growing literature attests to the increasing use of palynology for climatic, vegetational facies, and age studies. Future use of palynomorphs of all categories for paleoecological studies in general, and facies recognition in particular, seems promising. Toward the end of the Maestrichtian Stage the last of the great Cretaceous marine transgressions gave way to slow, worldwide episodes of regression, attended in some places by the prolonged development of swamp and mudflat environments and in other places by the onset of major orogenic disturbances. Relatively few areas of the world have records of continuous sedimentation spanning the Cretaceous - Paleogene interval, yet no dramatic geologic event seems to bisect the time boundary. The stratigraphy of the Mesozoic-Cenozoic passage is not agreed on, particularly in regard to the stratigraphic position of the Danian. Significant faunal changes, i.e., extinction of dinosaurs, ammonites, and rudistid pelecypods, did occur at the MaestrichtianDanian boundary and contributed to one of the noteworthy faunal gaps in the paleontological record (Newell, 1962). The paleobotanical record seems to have no gap of comparable magnitude, so that the CretaceousTertiary passage appears to have occurred without drastic vegetational change. This is not to deny that floral changes reflected in stratigraphic floral breaks are encountered at the Cretaceous-Tertiary boundary. The Uper Cretaceous assemblage contain many species of Proteacidites and
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161
Aquilapollenites and numerous specimens of a characteristic tricolpate grain whose colpi are located between its rounded apical angles. In the lower Paleocene assemblages the characteristic tricolpate species is not present, only one species of Aquilapollenites can be observed. Data from Paleocene distribution of corals and bauxite soils and from oxygenisotope paleotemperature measurements adduced in support of an inferred general cooling of the climate during that epoch, are not supported unequivocally by paleobotanical evidence. Southern Hemisphere bearing on character of Paleocene tropical floras hints at strong dominance by evergreen dicotyledons and palms, with lesser representation of ferns, grass, and Ephedra. Pollen floras contain many kinds of unidentified dicotyledonous pollen and grains. Late Tertiary Floras (Interpretation) One of the most critical problems in evaluating the paleoecology of a fossil-pollen flora is determining what constitutes evidence of local provenance and what represents pollen drift or long distance transport. The palynologist should evaluate three aspects: (1) the nature of the sediment, (2) abundance of the pollen type, and (3) reworking. The taxa identified from a fossil flora may be classified according to their present geographical distributions or according to the distributions of their nearest relatives. This effort provides a basis for estimating paleoclimates, and it can provide leads for identifying some of the unknown elements within the flora. Stratigraphic records of pollen phenotypes are enhanced if the climatic, ecologic, and floristic connotations of the plants can be determined. The more accurately and completely a fossil assemblage is compared with modem plants, the more reliable will be the resulting identifications. As a supplement to a modem pollen reference collection, compilations of photographs and drawings of modem pollen and spores may be helpful. Geographic affinity of a fossil flora can be usefully expressed in terms of the floristic province in which the majority of the modem relatives of the identified forms live today. Additionally, the present range of minor elements in the flora can be of interest. Most helpful in these determinations are regional floras in which the ranges of a modem genus or its regional species are mapped. Broad floristic provinces were defmed for North America by Gleason and Cronquist (1964). They recognised 10 floristic provinces that have large groups of species with similar distributions. They are given below:
1. Arctic or Tundra Province : Silene acaulis, Betula glandulosa.
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Encyclopaedia of Petroleum Science and Engineering 2. Northern Deciduous Forest Province: Larix laricina, Abies balsomea, Picea mariana.
3. Eastern Deciduous Forest Province: Fagus, Magnolia acuminata, Castanea, Gymnocladus dioica, etc. 4. Costal Plain Province: Taxodium, Nyssa aquatica, Osmanthus.
5. West Indian Province: Rhizophoza, Dipholis, Guettarda, etc. 6. Prairies or Grassland Province: Various Gramineae, Buchloe. 7. Cordilleran Forest Province: Pseudotsuga taxifolia, Sequoia, Abies lasiocarpa, Tsuga heterophylla, etc. 8. Great Basin Province: Sarcobatus, Pinus monophylla. 9. Californian or Chaparral province: Arbutus menziesii, Fremontia.
to. Sonoran Province: Larrea, Fouquieria, Bursera, Sirnmondsia. Genera now occurring in the Eastern Deciduous Forest and Coastal Plain provinces are common in the Miocene of the Western United States, e.g., Carya. Other eastern elements were widespread in the Western States and Alaska during Miocene time, e.g., Liquidambar, Nyssa, Fagus, Castanea, etc. These then grew with eastern hardwoods over a large area in western North America. Miocene pollen documents the presence of many East Asian genera in the New World Miocene, e.g., Pterocarya, which now has a limited distribution in China, Japan, and in the Caspian Sea region. It also was widespread in the United States, Canada and Alaska. Other East Asian genera with a similar history include Sciadopitys, Eucommia, Cunninghamia-Glyptostrobus, and Melia. It would seem that climatic preferences and ecological relationships of modem vascular plants apply in detail to Pliocene floras and in general to those of Miocene or Oligocene age. Northwestern Europe has been the scene of much palynological activities since the 1930 'so Much European pollen work has dealt with the Rheinische Braunkohle from the Rhine and Elbe River deltas- near Amsterdam, Cologne, and Berlin. These deposits are coastal moor and marsh sediments that range in age from middle Oligocene through early Quaternary. The Oligocene and Neogene floras of these deposits are diverse: remains represented include leaves, fruits, seeds, wood, and pollen. The general sequence as inferred from pollen and megafossil evidence indicates a cooling of climate from at least middle Oligocene through the Praetiglian, or fIrst glaciation. The floristic changes of the Europe Neogene resulted partly from secular cooling, but
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the changes were probably ameliorated by the presence of the Tethys sea during the Neogene. Some portant numerical changes taking place in pollen representation between the middle Oligocene and middle Miocene include these : (1) decrease in the species Tricolpopollenites liblarensis and Triporopollenites robustus, (2) decrease in the triporate pollen, and (3) increase in the Alnus, Fagus type and both winged and non-winged conifer pollen. Teichmuller (in Ahrens, 1958) has described a possible reconstruction of Miocene plant communities from the coastal marshlands. See Fig. 27.
Open water
Coal,; from torest swamps
Coal~~~e59raS'i
Coarse/fine
Detrital Gyttl8s
Fig. 27. Inferred moor types of the Miocene niederreinische Braunkohe in their probable lateral succession (After TeichmiilIer, 1958).
Early Miocene pollen floras have been described from Silesia and from the Lausitz basin. Late Miocene pollen floras are known from Stare Gliwice in Silesia and from the Konin deposits. Pollen and seed floras from Mizerna in southern Polland represent the early Quaternary section through Mindel and probably include the latest Pliocene. The Polish Miocene is rich in Tertiary relict genera. See Table 5. In Fig. 28 the relative importance of various geographic elements in the floras is plotted according to geologic age. In Poland pollen of Gramineae and Compositae are rare or lacking in the early Miocene but become more common in younger beds. Megafossil evidence of arctic species does not appear in Poland until the Mindel, or third European glaciation. Hungarian late Miocene and early Pliocene floras have a general similarity to floras of similar age from north-western Europe. Pollen, spore, and plankton floras from primarily marine deposits of late Oligocene, Miocene, and Pliocene age in Romania are summarized. Each of these floras is distinctly more cool temperate than are floras of corresponding age from northwestern Europe. The evidence from Miocene and Plio-Pleistocene pollen floras of the Russia is summarized in a series of maps showing
Table-5 Percentages in the Total Pollen Count of Certain Tertiary Relict Groups in the Late Cenozoic of Poland Early M,ocene
Late Miocene
Pliocene
4 - 80
1 - 20°
0-1
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1-43
0-1
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1 - 18
Taxon
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and Cupressaceae
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0-2°
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0-3°
0-5
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1- 5
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+
1- 3
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-°
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Mizerna III (= Cromerian)
Fundamentals of Palynology
165
Pliocene
Fig. 28. Decreasing geographic elements in late Cenozoic floras of Southem Poland (After Tschudy and Scott, 1969).
inferred vegetation patterns. Early Miocene vegetation of the Russia is thought to have been subtropical in eastern Europe north of the Black Sea as far north as latitude 55 degree; subtropical elements were present in a predominantly warm temperate forest vegetation in northern White Russia west of the Urals and in the Far Eastern province along the Pacific Coast. The remainder of the Russia where records are available, which is the entire midcontinent west of Lake Baikal, had primarily a rich, forest flora of warm temperate character. Floras around the North Pacific basin were similar on a generic and in many cases even a specific basis during the early and middle Miocene. Altitudinal zonation existed during the middle Miocene, when confier forests dominated the highlands above 700 metres, but mixed hardwoods of a temperate character grew in the lowlands of the Pacific Northwest and in the southern Alaska. The cooling of the late Miocene brought about a severe reduction of temperate woody forms in Alaska and a restriction of these forms to low elevations in nortliwestern conterminous United States. On a generic basic the Alaska· flora was modernized by the end of Pliocene. The floras of high latitudes (Alaska and nearby Siberia) and those of the Pacific Northwest had few species in common by Pliocene time. Hence, through the latitudinal differentiation of climate during the Neogene the temperate floras of old and New Worlds became isolated from each other. A sequence of late Oligocene and Neogene leaf and pollen floras of the Cook Inlet area and of the Alaska Range in southern Alaska spans much of the late Cenozoic.
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The latest Oligocene pollen floras are characterized by the presence of extinct taxa, e.g., Aquilapollenites, Orbiculapollis, etc. A feature of the Neogene pollen floras is the appearance and increase of groups now characteristic in Alaska, e.g., Cyperaceae, Typha, Artemisia and Compositae, Polygonum etc. In southern Alaska during the middle and late Miocene plant evidence indicates a major deterioration of climate. During the middle to late Miocene a group of genera became extinct in the region, e.g., Fagus, Liquidamber, Nyssa. The Neogene climate in the Pacific Northwest, as indicated by pollen evidence was warm temperate to subtropical in the Miocene and temperate in the Pliocene. Neogene megafloras of Japan has been summarized by Tanai (1961). A late Oligocene or earliest Miocene floras at Creede, in southwestern Colorado in the San Juan Mountains, is severely depauperate compared to the early Oligocene Florissant flora but includes many genera that now grow in Colorado. Recent potassium-argon isotope dates establish the age of the Creede flora at 26 million years. The Troublesome Formation in Middle Park, north-central Colorado yielded a pollen assemblage from a vertebrate horizon of middle Miocene age, e.g., Pinus, Acer, Gramineae, Umbelliferae, etc. Like the Creede flora, the assemblage is composed dominantly of pine and spruce pollen. Pliocene floras from Wyoming, Idaho, and Arizona have a generic aspect similar to those from Colorado. A leaf flora of late Miocene age at Trapper Creek contains forms such as Sequoia, Carya, Nyssa, etc., now exotic to the Rocky Mountains, plus forms now characteristic of the area, e.g., Pigus, Abies, Acer, etc. The pollen flora of the Salt Lake Formation and of the Banbury Basalt are greatly impoverished compared with the Trapper Creek flora. A diverse pollen flora from the Glenns Ferry Formation of Blancan age in the western Snake River plain represents plants now native to Idaho, except for rare pollen of Carya and Ulmus-Zelkova. The succession of Miocene, Pliocene, and Quaternary pollen floras from southern Idaho demonstrates grac,lual loss of broad-leaved tree genera that still persist in Central and Eastern United States and along the Pacific Coast. The loss of broadleaved trees from the flora of the central and northern Rocky Mountains was undoubtedly progressive, owing to gradual deterioration in regional climate and the rise of mountains. Though two or three leaf floras of Miocene age have been reported along the East Coast. Reconnaissance work provides a skeletal picture of common pollen types in three Miocene formations in Maryland, i.e., the Choptank and Calvert Formations, both of middle Miocene age, and the St. Mary's Formation of middle and late
Fundamentals of Palynology
167
Miocene age. Most of the plant group identified area represented in the modem flora of the region. Ephedra does not grow in Eastern United States. Miocene pollen floras from Eniwetok, Fiji, Bikini, Palau Islands, and Guam indicate that the Miocene vegetation contained Micronesian plant genera that since have been eliminated from the islands. Early and middle Miocene pollen floras of New Zealand are dominated by Nothofagus. Bombax and Capaneidites types make their last appearance in the late Miocene. The Gatun Formation (Miocene) in the Panama Canal Zone furnishes evidence of Miocene vegetation in the New World tropics. Pollen and spores types were reported: Bombax, Anemia, Trichilia, Cupania, Roupala etc. In Panama Canal Zone, there have been few alterations or generic eliminations from the flora since Miocene time. Late Tertiary Floras (Summary) In the Northern Hemisphere at high and middle latitudes pollen evidence records a Miocene climate that was warmer and with less seasonal variation than at present. In many areas subtropical plants, such as members of the Sapotaceae and Meliaceae, grew alongside warm temperate and cool temperate plants. These groups for the most part are not found together today, but they grew only a few miles apart in mountainous terrain of the subtropics. Though the late Oligocene Climates brought some subtropical elements as far north as latitude 63 degree N in Alaska and the Russia, most of these genera extended only as far north as about latitude 40 degree N during the early Miocene along the Pacific Coast of North America and to about latitude 50 to 55 degree N in Europe and maritime East Asia. Today subtropical elements extend northward to about latitude 25 degree N in most areas. The early Miocene vegetation occupying the mid-latitudes of the Northern Hemisphere was mixed warm temperature and SUbtropical, with the true tropics apparently restricted to relatively low latitudes, i.e., 35 degree N. Middle Miocene leaf floras of Japan and the Pacific Coast of the United States indicate that the climates were warmer than early Miocene ones and that some subtropical broad-leaved evergreen elements moved northward to about latitude 45 degree N during that time. Many genera now restricted to the humid Eastern United States and to temperate parts of China and Japan ranged into Western United States and Europe. Limited evidence from low latitudes suggests that Miocene floras these were not significantly different from the local floras of today. By late Miocene time subtropical elements retreated to a position south of latitude 40 degree N, leaving the north latitude a region of strictly
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temperate vegetation, even in Siberia, Alaska, and coterminous United States. An exception is Western Europe, where a few subtropical forms persisted as far north as latitude 50 degree N until Pliocene time. During the late Miocene a temperate flora that was relatively homogeneous on the generic level occupied lowlands in the entire North Pacific Basin, though montane vegetation was more boreal in aspect. Now desert areas of Western United States and South-Central Russia showed development of steppe or subarid scrub vegetation as early as late Miocene. In Pliocene time the widespread climate deterioration decreased the ranges of temperate plants. The role of Pinaceae increased significantly in the high northern latitudes, replacing the earlier abundance of mixed hardwoods and Taxodiaceae. Pollen of herbaceous groups was increasingly important and more diverse than earlier. Deserts developed in the sea of Aral area of southwestern Russia and the Great Basin of Western United States, and semiarid conditions developed in the rainshadow of the Rocky Mountains in Colorado and Wyoming. By Pliocene time the mesophytic hardwood floras of Old and New Worlds were separated by the opening of the Bering Straits and by climatic barriers that limited the northern distribution of temperate plants to relict sites. Mississippian and Pennsylvanian Palynology
Most spores and pollen grains from Mississippian and Pennsylvanian rocks are believed to have been derived from vascular plants. These spores may be homospores, which are essentially the same size for a given species. The homospores, microspores, prepollen, or pollen have been called small spores, denoting a size generally less than 200 microns. Most Paleozoic spores can be divided into groups on the basis of symmetry: (a) bilateral and monolete, and (b) radial and trilete. A third division, alete, would include spores and pollen grains that lack an aperture. The presence of a vestigial trilete aperture in members of the Pinaceae is strong evidence that Pityosporites and other Paleozoic bisaccate genera have radial symmetry. Bilateral, monolete spores assigned to the genus Laevigatosporites are a conspicuous part of Pennsylvanian assemblages throughout the world. Radial and trilete spores, the most abundant spore types, occur throughout the Mississippian and Pennsylvanian Periods, e.g., Calamospora, and Punctatisporites. See Fig. 29. Radial, trilete spore without equatorial structures tended to preserved or flattened in good proximo-distal
Fundamentals of Palynology
169
o Fig. 29. Mississippian-Pennsylvanian spore genera (After Tschudy and Scott, 1969).
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orientation. Radial and trilete spores possessing continuous equatorial structure are present in Mississippian and Pennsylvanian strata. Radial and trilete spores which are roundly triangular to triangular in proximodistal view and which posses continuous equatorial thickening tended to be flattened in good proximo-distal orientation, e.g., Murospora.
An ideal system of classification is one in which only morphologic features are required to classify fossil spores and pollen. Theoretically, according to the "International Code of Botanical Nomenclature", a single texon may have but one valid name based on priority and other features of the code. Richardson (1964) and Butterworth (1964b) reported their fmdings relative to the stratigraphic distribution of genera. See Fig. 30. Most Mississippian and Pennsylvanian spore and pollen genera are radial U.S A MIIl-CONTINENT AND MISSISSIPPI VALLEY
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Fundamentals of Palynology
171
and trilete. We should consider morphology and afftnities of radial and trilete sores, prepollen, and pollen. Accordingly the subject is treated under the following categories:
1. Spores lacking equatorial structures. 2. Spores with continuous equatorial structures. 3. Spores with discontinuous equatorial structures. 4. The saccate spores, prepollen, or pollen that can be subdivided into the monosaccate, bisaccate, and multisaccate groupings. A megaspore may be defmed as a spore, produced by heterosporous plants, that gives rise to th~ female gametophyte or mega-gametophyte. Division of the individual spore mother cell (meiosis and mitosis) results in four megaspores. Usually megaspores from Paleozoic plants are significantly larger than their corresponding microspores. Some pollen grains of modem gymnosperms and angiosperms are as larger as or larger than their corresponding megaspores. Devonian megaspores are appreciably smaller in diameter than Carboniferous megaspores and that there is a continuous decrease in megaspore size from the Carboniferous to the Upper Cretaceous. The stratigraphic occurrence of megaspores is inevitably linked with the occurrence of heterospores plants. Triletes is associated with heterosporous, free-sporing lycopods. They have a stratigraphic range from late Devonian to Holocene. See Fig. 31. Sectio Lagenicula spores are characterized by a unique structural development of a portion of the pyramic surface resulting in an elongation, or beak, in the apical areas of the pyramic segments. Sectio Aphanozonati spores are characterized by being originally more or less saucer shaped and appearing circular to oval shaped in proximo-distal view. These spores ranges in size from 180 microns to 3000 microns. Sectio Zonales species are characterized by the presence of an equatorial rim and a zone composed of anastomosing appendages that form a more or less solid flange, or open. Sectio Triangulati spores are characterized by the presence of an equatorial, solid, membranous flange and are of small to medium size. They range in size from 350 microns to 1000 microns. Sectio Auriculati spores are characterized by the presence of arcuate thickening that are bulbose projections on "ears" developed at the radial extremities. The spores are subtriangular to trilobate in proximo-distal view. The genus Cystosporites is radial and has a trilete aperture. Fertile spores are more
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Encyclopaedia of Petroleum Science and Engineering
4
5
6
Fig. 31. Megaspore genera (After Wilson, 1959).
or less oval in proximo-distal view and saclike in longitudinal. Abortive spores are circular to oval in transverse and planes. The genus Calamospora is unique in that the generic circumscription includes homospores, microspores, and megaspores. Paleoecology
Pollen and spores, microscopic but vital elements in the life histories of the plants they present, do no more than suggest the life form of the
Fundamentals of Palynology
173
parent plant and are not necessarily found at the locality at which the parent plant grew. There are many limitations. Almost of the Normapolles group of pollen grains prevalent in the Late Cretaceous are extinct. That the plants themselves may have changed in their ecological requirements with time must be seriously considered. When dealing with assemblages of dispersed spores and pollen of Recent or near Recent age palynologists have been able to do a remarkable job of reconstructing past climates and past plant communities. Families and genera known to be limited to restricted ecological conditions are rare. Nevertheless, when such fossils are found careful inferences or conclusions based on them may be sound. Inferences based on fossil associations, especially in Tertiary and older rocks, are much more reliable than those derived from single species. The coals derived from the different associations are distinct petrographically. Inferences can be derived from the characteristics of the fossils. These inferences are based on the morphology of the fossil spores or pollen grains and include such features as the presence of thick or thin walls and the distributive mechanisms inherent in the fossils themselves. Float mechanisms, such as those on fossil Azolla spores, point to an aquatic habitat like that occupied by modem Azolla species. Inferences from adaptive mechanisms such as the wings, or sacs, on conifers have been made. On the basis of size and sculpture we may conclude that the fossil pollen species was probably adapted to distribution either by wind or by insects. Entomophily, pollination by insects, is more common in tropical humid, or rainy climatic conditions than is anemophily, pollination by wind Airborne pollen is constantly washed out of the humid tropical air by rain. Insect pollination under such conditions is a more effective fertilizing mechanism. Distribution of pollen by wind on a large scale is chiefly confmed to temperate and cool climates. Identity of fossil pollen with pollen from extant genera and species of plants is the most reliable basis for paleoecological interpretation. Members of the Gramineae signify nearby grassands. Juncaceae is a family that is composed of aquatic or semiaquatic members. Members of the Droseraceae are limited to boggy or swampy regions. Many members of the Chenopodiaceae are common inhabitants of dry, open localities. Nothofagus is at present a genus confmed to the south temperate zone. Palynology (Applications)
The application of palynology to geologic or stratigraphic problems involves the definition and delineation of specific strata, or segments of
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the stratigraphic column, in terms of the palynomorphs derived from these rocks. The concept that some stratigraphic segments can be identified and distinguished from other segments is based on the fact that plants have undergone evolutionary change during geological time. Evolutionary change is reflected in the parts preserved, i.e., pollen, spores, and some other structures (as well as in the plants as a whole). The preserved remains of plants will reliably identify and distinguished segments of the geologic column. Ecological factors, including climatic and edaphic, may also be reflected by changes in the floras of successive rock layers. The principal applications of palynology are to the correlation of strata and to the determination of the relative ages of strata. Age determination must be based on the correlation of palynomorphs assemblages of a particular stratigraphic section with the palynomorph assemblages from a similar section that has previously been reliably dated by some other means. Initially dating is done by comparison of palynomorph assemblages with vertebrate or invertebrate fossils of the same rocks. Sometimes the principle of interpolation is employed, e.g., a continental bed, which yields a plant-microfossil assemblage, can be given an approximate date if the overlying and underlying strata have been dated by some means other than pollen and spores.
Palynological Characterization of the Eocene Early Tertiary plant mega-fossils from Holarctic recovery sites indicate the existence of widely developed forests of mixed deciduous hardwoods and temperate conifers. Although relatively few pollen floras of Paleogene age have been described from high-latitude northern-sites, the palynological evidence in general agrees with that derived from leaf, fruit, and seed remains, and numerous genera are now known from both megafossils and microfossils. Cranwell (1959) has alluded to the difficulties of Antarctic collecting and to the disappointments of barren samples. Bunt (1956) speculated that the Macquarie fossil-pollen flora might be closely related to the Tertiary floras of the Antarctic .. Palynomorphs from calcareous rocks collected well within the Antarctic Circle were described. The assemblage is dominated by hystrichospheres and dinoflagellates. Pollen are scarce and small, although well preserved. They include Nothofagus and some palm and proteaceous forms. Pollen size and frequency, and the association with hystrichospheres and dinoflagellates, might indicate a deposition environment of offshore waters of normal salinity and low turbidity.
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The frrst extensive flora of the Neotropical Tertiary is that of the Eocene Wilcom group of the Gulf Coastal Plain of Southern United States. Known primarily from leaf remains and to a lesser extent from microfossils, the flora serves to characterize the Neotropical early Eocene. The plant families best represented from megafossils, e.g., Lauraceae, Araliaceae, Sapotaceae, Meliaceae, etc. Jones (1961) reported that the commonest pollen constituents were pine and oak. Wilcox flora is largely coastal and indicates a warm temperature climate and an abundant rainfall. Wilcox sediments from Arkansas yielded 62 spore and pollen types, comprising a mixed assemblage of tropical, subtropical, and temperate genera, including Anacolosa, Symplocos, Carya, etc. in company with the pine and oak pollen. The Arkansas sediments were deposited under brackishwater conditions. The flora of the Central American migration route suffered more widespread selectional pressures than did the flora of northern South America, which retains its essential Tertiary character to this day. The middle Eocene Green River flora is yet another Neotropical Eocene flora known from both megafossils and microfossils. The Microfossils consist of pollen from anemophilous trees and shrubs indicative of a temperate assemblage. The vegetation contributing to the Green River pollen flora grew under less well watered conditions than prevailed during an ealier and later mid-Eocene stage. The succeeding middle Eocene Claiborne Group includes some of the most fossiliferous sediments in the world, but its megaflora is not so rich as that of the Wilcox. Evidence from the major megafloras of the Pacific coastal region and the adjacent interior basins seems clearly indicative that the prePliocene forests were broadleaf evergreens growing under humid, warm temperature to sub-tropical climates. The Chalk Bluffs flora's greatest resemblances lie with the floras of southeastern Asia and Southeastern United States, and those of eastern Mexico and Central America. Van Der Hammen's (1954) palynological study oflate Mesozoic-early Tertiary Colombian coals and lignites represents the picture of densely forested tropical climax vegetation, marked by the cyclic fluctuations and alternating dominance of ferns, palms, and unidentified dicotyledons. Europe's widespread Eocene subsidence of the continent resulted in the development of lacustrine, river-swamp, and embayment habitas. Repeated interplay of strand-line changes and luxuriant plant growth, continuing through the Miocene, produced considerable intercalations of vegetational debris, with continental sediments contributing to one
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of the major coal-forming periods of earth history. On the basis of plantmicrofossil evidence alone the existence of the following major communities may be inferred for the Central European middle Eocene:
1. Swamp forests with Taxodium and Nyssa. 2. Riverbank and grove habitats of Sabal and other palms. 3. Shrub thickets of Myricaceae-Cyrillaceae species, SapotaceaeSymplocaceae species, Aralia, Hex, and polypodiaceous ferns. 4. Hardwood forests of fagaceous species, of Fraxinus, Engelhardtia, Tilia, Alianthus, Pterocarya, Carya and Comus. 5. Conifer forests of Sequoia, Pinus, Picea, together with Rhub, and schizaeaceous ferns. As in the case of the Wilcox and Claiborne spore and pollen floras, the London Clay pollen flora also contains grains belonging to temperate families such as Betulaceae and Fagaceae. The most interesting pollen found in the London Clay is Nothofagus. See Fig. 32. Most of the generic determinations are correct and being mindful of high proportion of Australian and Malasian genera in the London Clay flora. Eurasia served as the "bridge" for plant migration between the southern continents. The older podocarp forests of Australian Tertiary gave way sometime between the Paleocene and middle Eocene to a dicotyledon-dominated "Cinnamomum flora", which developed with considerable uniformity across much of Australia. Leaf fossils indicating the assemblage of such genera as Banksia, PittospoI1l1Il, Northofagus, Callitris, Phyllocladus, etc., suggest an equable climate with unifonnly distributed rainfall, comparable to conditions prevailing in mountain areas of New Guinea. The families Myrtaceae, Olacaceae, Santalaceae, etc., are represented by Eocene pollen from numerous localities in Australia and Tasmania. Prominent pollen geneal are Casuarinidites, Myrtaceidites, Proteacidites, Cupanieidites, etc. The podocarp species that had dominated the New Zealand forests into the Cenozoic were supplanted finally in late Eocene time by Nothofagus matauraensis of the Brassi group, the group whose modem counterparts are confined to New Guinea and New Caledonia. The New Zealand pollen flora of the Eocene is associated with pollen of the Bombacaceae, Sapindaceae, and Ephedraceae. Palynological Characterization of the Oligocene The Colorado Florissant Formation, an intermontane lacustrine deposit of volcanic ash and tuff, is well known for the abundance of its
177
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furrows (inaperturate) or with performed openings or thin areas (aperturate). In the aperturate class of pollen grains there is tremendous variations in the number, size, distribution, and structure of the apertures. In general apertures have been related to the basic functions of (a) provision of a place of emergence for the developing pollen tube and (b) acconunodation to the significant volume changes that occur in the
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Fig. 61. Electron micrographs of ultra thin sections.
pollen grain as a result of rapidly changing humidities. The nonapertural exine is the outer, resistant layer of the sporoderrn. Its surface configuration can be extraordinarily intricate and texonornically distrinctive. The presence of ornate structuring of the exine surface has
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been correlated in many instances with insect pollination. Functionally, nonapertural exine has been associated with protection against excessive water loss, irradiation, and mechanical injury (Wodehouse, 1935). In the maturation of the sporoderm the intine is the least formed zone, or layer, immediately adjacent to the protoplast. It is usually absent in fossilized or acetolyzed specimens. Structurally the intine layers associate directly with apertural structures. Usually at the close of telophase II of meiosis a tetrad of four micro spores is produced. The microspores are enlosed by a special callose wall, formed within the original pollen mother-cell wall. Two patterns of development of the usually intricate sporoderm of the mature pollen grain or spore have been contrasted. In one of the major control of sporoderm development is associated with the microspore protoplast, whereas ther other pattern associates sporoderm growth largely with external phenomena involving material of tapetal origin after the microspores are released as individual cells from the investing special callose wall. Exine structure is usually uniform within a tetrad. During early meiotic stages cytoplasmic interconnections would appear to provide for ready exchange of materials, including maternal gene products, throughout the entire population of pollen mother cells. At the start, the surface (plasma membrane) of each of the microspores of the tetrad enclosed within the special collose wall takes on a distinctive configuration that is somewhat suggestive of pinocytosis (Heslop Harrison, 1964), which serves as a template or primexine, for subsequent exine development. The primexine (template) of the microspore gives way to the mature exine pattern through relatively rapid deposition of the resistant sporopollenin. Finally, after completion of the various layers, or zones, of exine, the intine appears between the innermost layer of the exine and the plasma membrane. In most taxa, during the development of the sporoderm, collumellae appear first in ontogenetic time, followed by the tectum and the foot layer, with the endexhte of varied texture, if present, usually developing just prior to the appearance of the intine. Outer surface of mature pollen grain or spore are: (1) perine, (2) exine, and (3) intine. Inner boundary of sporoderm is in contact with plasma membrane of protoplast.
Systematics and Nomanclature in Palynology Application of the scientific method to systematic studies requires ability to deal with abstract concepts. Taxonomy involves systematic
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treatment of group concepts that are generalizations and hence abstractions. The real goal of systematic botany is organization. This goal should be extended to cover the plant kingdom and to include all identifiable plants, both fossil and modem. Taxonomy in general depends on the uniformitarian principle of heredity and evolutionary descent, regardless of whether the organisms are known to us as modem or as fossil. All plants, fossil or modem, have had ancestors, i.e., all plants have been derived phylogenetically back to the point of initial organismal differentiation. Species consist of populations projected in time. Commonly the populations are as variable as human beings, because at any point in time there may be several lines of incipient evolution within them. Useful taxonomic distinctions must be based on criteria that appear in historic perspective to have value in classification. Names applied to plant and animal population should represent recognizable taxa but forms that integrade between related species should not be ignored. None of the processes of organization, i.e., classification, taxonomy, or systematics, depends in any way on nomenclature. Rules that apply solely to the mechanics of handling names of taxa are given in ''The International Code of Botanical Nomenclature" (Lanjouw, 1966). Priority is a most important principle for determining the name of any taxon of a particular position, rank and circumscription. Circumscription depends on taxonomic decision, but the nomenclatural decision is automatic and depends on the date at which verifiable requirements have been met to entitle a name to legitimate treatment. The Criteria for the legitimacy of species names thus become the minimum of essential requirements for validating the name of a species. In nomenclature consideration we need not enter into the taxonomic problem of whether a taxon deserves assignment to species rank. Nomenclature involves the philosophy of precision in scientific communication. The appropriate use of nomenclature is important. Nomenclatural legitimacy is essential. Fossils are not now living, but their claim to taxonomic classification is based on the point of view that they represent, and may be used as a basis for interpretation of, organisms once living that are comparable to those of the present day. Plant microfossils, including fossil spores and pollen and any other determinable microscopic objects, first should be regarded as the representatives of plants. There are two means of designating and kind of fossils specimen. One designation indicates its taxonomic position and the other designates its morphology. A species represents a taxon of plants. Taxa that deserve to be named obviously should be as
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consistent in their botanical significance from one group to another as information permits. Most systematists consider that the only natural classification in a phylogenetic one. Many indirect types of evidence may provide evidence of phyletic diversity, e.g., if spores of virtually identical morphology are genetically related, they are not likely to show a consistently disjunct stratigraphic occurrence. If spores of somewhat disjunct stratigraphic occurrence are placed within a common species or genus, we may reasonably infer that the true stratigraphic range was probably continuous. All groups of true phyletic relationship have a continuing stratigraphic range from the time of their inception to the time of their extinction or diversification. A phyletic approach to taxonomy is more meaningful. The same functions can be served and virtually similar morphology can be achieved by different methods of growth. In spite of functional analogies, the disseminules of different groups differ as much as they do. There are great differences in the extent of phylogenetic convergence. The further separated the two convergent lines have become in ecologic character, the more important it is that convergent features be recognized. Some types of spores show long stratigraphic ranges that probably indicate the continuing existence of a particular group of plants, e.g., Tasmanites range in marine environments from Ordovician to Recent. These microfossils may represent cysts and are only spore like in morphology. Schizaeaceous spores have ornamentation in which ridges usually are ornamented by a characteristic tuberculation. Many other variations have been noted, and several genera have been distinguished for this reason. Organ genera consist of groups of plants allied within the same plant family that are defined by functionally related and commonly connected sets of biocharacters. The families of plants are based, like other taxa, one classification proposals of competent systematists. Appropriate familial classification depends on an acute sense of proportion and judgement, tempered by a reasonable concession to taxonomic tradition based on previous studies of the group. In paleobotany general alliance is indicated by discoveries that are still sometimes spectacular. Although a phylogenetic system is of the greatest fundamental importance, informal systems based on various kinds of plant microfossils have been applied successfully for stratigraphic correlation. Fundamentally, morphologic systems of classification are not taxonomic. For morphologic purposes convenience governs rather than priority. Also morphologic systems employ terminology rather than
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nomenclature. The week point in the strictly morphologic approach to plant-microfossil classification lies in its distinct disregard of phylogeny and phyletic relationship. A clear differentiation between anatomicalmorphological and taxanomic concepts is particularly essential in the systematic study of fossil plants. In an antificial (special) system of classification all definable biocharacters are treated very much alike. Organisms are classified according to resemblance in form. According to a phyletic system, if there is any reasonable basis for recognizing the heterogeneous elements, these elements can be separated in taxonomy. The contrast letween an artificial system of classification and one reflecting ph logeny is best illustrated by differences in treating homoplasy, th results of convergent evolution. Taxonomic assignment should be a means of indicating an author's evaluation of phyletic affinity. Microfossils still deserve description because they are of use for purposes of local correlation. Descriptions should be adequate and cover all of the significant characters. Benson (1943) quoted the thoughtprovoking definition of intelligence as "the ability to recognize the significant elements in a situation." A cardinal principle of taxonomic organization is the arrangement of taxa according to what you believe in phyletic ally most probable. Proposals of taxa have much unstated, so that the reader must work with minimum information. Formal nomenclature is not designed to reflect morphologic resemblance. If a scientist is convinced that a proper genetic (phyletic) alliance exists, he must attempt to be consistant in expressing this conviction. Because of the inherent variability of biological material, taxonomy is not an exact science, and for this reason no solutions are unique. Emphasis should be placed on the personal responsibilities of scientists who do taxonomic work, i.e., to work according to the spirit of the Code. A list of those regularly authorized in given in Table 6. Additional unspecified categories also may be used if needed, provided that their rt.I!'~.I!'~~~,~~#,"',"' ....fi,"'~ YEA R
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APPENDIX-E NEWS IN FOCUS INDIA TO SOON HAVE A RESEARCH BASE IN ARCTIC TOI 2.9.2007 Ny Alesund (Norway): India will soon have a permanent postal address in the Arctic. Taking advantage of the unique international Svalbard Treaty signed in 1920, to which it was a signatory, India will be able to set up a permanent research station at Ny Alesund, on the Svalbard archipelago which comes under Norwegian sovereignty, boosting its knowledge of climate change, other critical natural phenomena and the disturbance humans cause to nature's processes. Perhaps waking a bit too late in the day, considering India has already sent 26 missions to the Antarctic and has two permanent bases there, the research base at 79 degree north will be set up under a fiveyear contract with the Norwegian government and Kings Bay, the Norwegian government-held company that runs the logistics at the research station.
New Address: (From Left) Researchers S.M. Singh, e.G Deshpande and Dhruv Sen Singh, who were part of the mission to the Arctic.
The Svalbard Treaty allows every signatory country, that includes Afghanistan, to set up any business and activity on the archipelago -
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which earlier was better known for its coal mining industry -as long as it falls within Norwegian regulations. Formal negotiations between the two countries are close to completion for India to take position close to the North Pole. The move to set up the permanent station at Ny Alesund matured with India sending its fIrst Arctic mission recently. Three of the fIve researchers sent as part of the fIrst of the two teams comprising the mission have already made themselves at home at the international research station. Rubbing shoulders with the Chinese, Germans and French, and obviously the Norwegian researchers, they are busy collecting samples. The sun never sets, quite literally in the Arctic summer. Besides the bags of tagged samples one finds kept in an old school building of the camp, there are other tell tale signs that Indian researchers are at workempty packets of Indian cigarettes, though stashed well in the bins, not strewn around. "This is not unfamiliar climes as we have a long history in the Antarctic but this surely provides completely new avenues for research to us," explains an excited Dr C G Deshpande, scientist at the Indian Institute of Tropical Meteorology and member of the team. In his politeness, he never lets out the political significance of his research at the Arctic. His measurements of aerosols (particles of pollution generated naturally as well as from human activity) will help India pin down the impact of pollution from the developed countries on the Arctic, in contrast to studies that have blamed Indian for adding to the aerosol pollution earlier. Dr S M Singh, scientist at the National Centre for Antarctic and Ocean Research, the second of the triumvirate at Ny Alesund, is picking up soil and water samples around the station. An ankle sprained, he still walks around for his pound of soil. "There is little time, we have only two more weeks here. I am collecting microbes from the region, to compare with those collected at the Antarctic. These microbes can help measure changes in seasons as well as provide potential solution to diseases like leukoderma. " Dhruv Sen Singh, reader in the Department of Geology of Lucknow University, listens to Lata songs in the evenings, while munching on sweets and namkeen in his warm room at the station, and completes the triumvirate. His job: study glaciers and their habits.
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Ottawa: In the latest of a series of claims over portions of the Arctic, Canada said on Friday that it planned to build two new military bases in the for north to assert its sovereignty over the Northwest Passage. The status of the shipping route, navigable only with the aid of icebreakers for a small part of the year, has been the source of a longstanding dispute that has pitted Canada against the United States and Russia. Warming climate trends may reduce ice in the passage and make it a substantially shorter alternative to the Panama Canal for commercial shipping. The seabed under the route may also contain oil, gas and minerals that could be extracted if the ice cover diminishes. Prime minister Stephen Harper, who has been touring the Canadian Arctic for several days, said the military would convert a former mining site in Nanisivik, in the territory of Nunavut, into a deep-water port and ship refueling station. Existing government buildings in Resolute Bay, Nunavut, will be turned into an Arctic training center for the army, and the Canadian Rangers, mostly made up of Inuit volunteers, will be increased by 900 members and re-equipped. Harper's tour and announcements took place after a Russian mission planted a tiny flag in a titanium capsule on the seabed at the North Pole last week. While the effort was billed as a claim on the territory, it was seen as mostly symbolic. TO! 22.8.2007
ISLANDS EMERGE AS ARCTIC ICE SHRINKS Ice May Disappear by Middle of Century: Expert Ny Alesund, Norway: Previously unknown islands are appearings as Arctic summer sea ice shrinks to record lows, raising questions about whether global warming is outpacing UN projections, experts said . . Polar bears and seals have also suffered this year on the Norwegian archipelago of Svalbard because the sea ice they rely on for. hunts melted far earlier than normal. "Reductions of snow and ice are happening at an alarming rate," Norwegian environment minister Helen Bjoernoy said at a seminar of 40 scientists and politicians that began late on Monday in Ny Alesund, 1,200 kms of the North Pole. "This acceleration may be faster than predicted" by the UN climate panel this year, she said. Ny Alesund calls itself the world's most northerly permanent settlement, and is a base for Arctic research.
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The UN panel of 2,500 scientists had said in February that summer sea ice could almost vanish in the Arctic towards the end of this century. It said warming in the past 50 years was "very likely" the result of greenhouse gases caused by fossil fuel use.
Melting Point: Ice has fallen below the 2005 record low absolute mmimum, say experts.
"There may well be an ice-free Arctic by the middle of the century," Christopher Rapley, director of the British Antarctic Survey, told the seminar, accusing the UN's Intergovernmental Panel on Climate Change (IPCC) of underestimating the melt. The thaw of glaciers that stretch out to sea around Svalbard has revealed several islands that are not on any maps. "Islands are appearing just over the fjord here" as glaciers recede, said Kim Holmen, research director at the Norwegian Polar Institute, gesturing out across the bay. "We're already seeing adverse effects on polar bears and other species." "I know of two islands that appeared in the north of Svalbard this summer. They haven't been claimed yet," said Rune Bergstrom, environmental expert with the Norwegian governor's office on Svalbard. He said he had seen one of the islands, roughly the size of a basketball
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court. Islands have also appeared in recent years off Greenland and Canada. Rapley also said the IPCC was "restrained to the point of being seriously misleading" in toning down what he said were risks of a melt of parts of Antarctica, by far the biggest store of ice on the planet that could raise world sea levels. Still, in a contrast to the warnings about retreating ice and climate change, snow was falling in Ny Alesund on Monday, several weeks earlier than normal in a region still bathed by the midnight sun. About 30 to 130 people live in the fjordside settlement, backed by snow-covered mountains. Bjoernoy said it was freak storm that did not detract from an overall warming trend.
TOI 25.7.2007 INDIAN TEAM TO STIIDY ARCTIC GlACIERS New Delhi: With the government showing keen interest in increasing the country's scientific understanding of glaciers in the wake of global warming threats, India will soon send a team of researchers to the Arctic to study glacial geology and pursue research in other key fields. While India has sent 26 missions to the Antarctic and made its presence felt in the polar research fraternity, this will be its first foray towards the North Pole.
New Venture: This will be India's first foray towards North Pole.
Norway has agreed to host Indian scientists on its base at Svalbard, an archIpelago halfway between the North Pole and Norway. The Svalbard research camp of the Norwegian Polar Institute will be used by the Indian scientists for their research.
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India moved fast to utilise the opportunity when the Norwegian government offered visiting earth sciences minister Kapil Sibal facilities at its base in the archipelago for research. The ministry then asked key scientific institutions to put in proposals for possible studies. Fourteen proposals were received by the ministry, but after review, only eight were cleared. The approved proposals include research into geology. Arctic microbes and aerosols. While the second area of research, microbes, will have implications for biotechnology, the other two will add to Indian scientists' understanding of how the dynamics of climate change work. "We have already done work on the Antarctic microbes, so this will be a good follow-up for us," P S Goel, secretary, ministry of earth sciences, told TOL "Because this is our first foray into the area, our scientists will get an opportunity to gain basic knowedge on the regionand build on the knowledge gained in the Antarctic," he added. The Arctic research programme will be conducted in two phases with five experiments being carried out by the first contingent of scientists to go this year, and the rest three to be carried out by a second contingent in the second half of 2008. The Norwegian government has offered its base as well as the use of its equipment but the Indian contingent will have to take along some equipment with it to carry out the research. TOI 10.8.2008 TIlE POWER Wl'IlllN Clean geothermal energy could fuel the world in the future The ancient Romans drew on hot springs for bathing and heating homes without having to pay a single coin. That's because a clean, quiet and virtually inexhaustible source of renewable energy lies literally beneath our feet. The interior of the earth is hot-up to 6,500 degrees Celsius at the core and generally cooling off towards the top but still about 200 degress Celsius three to 10 kilometres below the surface. In Switzerland, Australia and elsewhere engineers are drilling down to these depths to tap the heat trapped in hot rocks by injecting cold water into the shafts and bringing it up again superheated to generate power though a steam turbine. They feel it could meet the electricity needs of nearly 10,000 households and heat over 2,700 homes. In India the potential for harnessing geothermal power has been under investigation since the late 1960s. Currently, an organisation
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incubated in lIT-Bombay is carrying out a year-long survey to assess the heat trapped beneath the Konkan coastline. Preliminary calculations indicate this could generate some line. Preliminary calculations indicate this could generate some 2,000 MW of power, reason enough for the ministry of non-conventional energy of Maharashtra, a state with a shortfall of approximately 5,000 MW, to be interested in co-funding the project. The total stored heat potential in India, however, is believed to be the equivalent of27.6 billion barrels of petroleum. At present, geothermal power supplies lees than 0.5 per cent of the world's energy. But global estimates of exploitable geothermal energy vary between 65 and 138 Gw. Taking this into account a 2006 MIT report concluded that extractable resources would be sufficient to provide all the world's energy needs for several millennia. What's needed is to move beyond easily developed hydrothermal systems, such as hot springs and geyers, and begin to tap the earth's deeper, stored heat, which is available everywhere. The report estimates that a billion dollars of investment in research and development over the next 15 years would lead to the enhanced geothermal systems (EGS) that would make this possible. Since the earth's heat is everywhere, EGS would deliver the ultimate form of energy security: no more dependence on suppliers of fossil fuels, or even uranium. And it's one of the cleanest forms of energy available: greenhouse gas emissions are close to zero. India ought to map its existing hydrothermal resources in Maharashtra and elsewhere, as well as collaborate in exciting research projects being undertaken in EGS in various countries. TOI 14.92007 'EARI'H MAY SURVIVE SUN'S DEMISE' Planet will Outlast Apocalypse After 5B Yrs; Venus will be Swallowed: Scientists
There is new hope that Earth, if not the life on it, might survive an apocalypse five billion years from now. That is when, scientists say, the Sun will run out of hydrogen fuel and swell temporarily more than 100 times in diameter into a so-called red giant, swallowing Mercury and Venus. Astronomers are announcing that they have discovered a planet that seems to have survived the puffing up of its home star, suggesting there is some hope the Earth could survive the aging and swelling of the Sun.
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The planet is a gas giant at least three times as massive as Jupiter. It orbits about 150 million miles from a faint star in Pegasus known as V 391 Pegasi. But before that star blew up as a red giant and lost half its mass, the planet must have been about as far from its star as Earth is from the Sun-about 90 million miles-according to calculations by an international team of astronomers led by Roberto Silvotti of the Observatorio Astronomico di Capodionte in Naples, Italy.
Ray of Hope
Silvotti said the results showed that a planet at Earth's distance "can survive" a red giant, and he said he hoped the discovery would prompt more searches. "With some statistics and new detailed models, we will be able to say something more even to the destiny of our Earth (which, as we all know, has much more urgent problems by the way)," he said via e-maIl. Silvotti and his colleagues reported therr results on Thursday in Nature. In an accompanying commentary, Jonathan Fortney of Nasa 's Ames Research Center in California wrote, "This system allows us to start examining what will happen to planets around stars such as our own Sun as they too evolve and grow old." The star V 391 Pegasi is about 4,500 light years from Earth and is about half as massive as the Sun, burning helium into carbon. It will
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eventually sigh off another shell of gas and settle into eternal senescence as a white dwarf. Meanwhile, the star's pulsations cause it to brighten and dim every six minutes. After studying the star for seven years. Silvotti and his colleagues were able to discern subtle modulations in the six-minute cycle, suggesting that the star was being tugged to and fro over a three-year period by a massive planet. "Essentially, the observers are using the star as a clock, as if it were a GPS satellite moving around the planet," said Fred Rasio of Northwestern University. This is not the first time that a pulsing star has been used as such a clock. In 1992, astronomers using the same technique detected a pair of planets (or their corpses) circling the pulsar PSR 1257+ 12. And only on Wednesday, X-ray astronomers from the Goddard Space Flight Centre in Greenbelt, Maryland, and the Massachusetts Institute of Technology announced that they had detected the remains of a star that radiation had whittled down to planetary mass circling a pulsar in the constellation Sagittarius. Those systems have probably endured supernova explosions. The Pegasus planet has had to survive less lethal conditions, although it must have had a bumpy ride over its estimated 10 billion years of existence. An expert said, "Stellar evolution can be a wild ride for a planet that is trying to survive, especially inner planets like Earth." TOI 8-12-2007
GROWING GREEN Negotiations in Bali for cleaner technology and development "It cows are causing global warming, and I ate a hamburger, could I claim carbon credits for helping eliminate a cow?" asks a reader in the letters coplumn of a US newspaper. Despite George Bush's refusal to commit the US to any international agreement that would adopt emissions targets, it is clear that climate change has com to impact people's consciousness everywhere. At the UN Framework Convention on Climate Cange meet in Bali, representatives from 190 countries have converged to compare notes and thrash out agreements on how to tackele the climate change challenge facing the planet. The US continues to stress the same points it raised at the last meeting in Montreal in 2005, that it would not consider any commitment unless India and Cina made similar promises, since together the three countries are the word's largest polluters. However, since carbon stocks in the atmosphere - that have triggered glonal warming - are the result of 300 years of devlopment in industrialised countries, the rich need to bear higher costs and take more
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responsibility. In a bid to be fair, the UN recommends "common but differentiated responsibility." India and China have attracted several projects from developed countries under the Kyoto Protocol's 'clean development mechanism'. Under this scheme, the investor earns carbon credits for setting up clean development projects, often with new technology. H9wever, what did not take off was saving 2 per cent of earned credits'in an 'adaptation fund' that would be ploughed back for tackling climate change risks. At Bali, discussions are on to activate this fund and to step up clean technology transfer to India, China and African countries. By taking the lead, the US could set an example in the developed world. Britain is talking ofa 75 per cent greenhouse gas emissions cutback by 2050 and has formulated a climate Bill detailing how it would go about achieving this. The Democrat-majority US Senate has now introduced a climate Bill; a first-time legislative initiative in the country that would ask selected industries to reduce emissions to 1990 levels by 2020 and by a further 65 per cent by 2050. The Bali conference provides a forum to discuss climate change issues so that some solutions get incorporated in the negotiating process to create a new agreement that would come into effect in 2012, when the Kyoto Protocol ends. India and China as developing world leaders ought to garner as much financial and technological assistance as they can from developed countries to reduce climate change risks to leapfrog their way to smart growth. That means going green without sacrificing growth and prosperity. TOI 6.12.2007 BALI MEET TO DECIDE FATE OF CARBON CREDIT New Delhi: The carbon cowboys of the world, including Indian carbon 'bonds', have all rushed to Bali for the global meet on climate change. The next 10 days of the UN meet could either deflate the existing $5 billion carbon credit market or expand it dramatically depending on the fate of the proposals before of the 190 countries gathered there. The carbon market is an offshoot of the ' Kyoto Protocol that demands greenhouse gas emission cuts from rich countries. The Clean Development Mechanism (CDM) under the protocol allows rich countries to buy carbon credits to offset their targets, in return providing funds to developing country entities to buy clean technologies. For Clean Technology
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On the table before the gathered 10,000 plus delegates will be several critical parts of the CDM mechanism. Knowing these could be as critical for developing countries like India as for rich countries like EU. No wonder, Bali is seeing one of the largest gathering of businessmen from around the world. Indian industry associations too have flown delegations, besides the carbon market dealers also landing up at the busy tropical station. One of the key issues to be thrashed out would be the inclusion of forestry as one of the many CDM project options. India Inc, especially the paper and pulp industry, is keen to make money from its forestry operations and the government wants to earn credits from 'avoiding deforestation' - a climate speak which means demanding money from rich countries for maintaining the forest cover at the cost of economic development. It is a contentious issue, because it could provide a lot of carbon credits if allowed under the CDM process which could also lead to a crash of prices with supply side seeing a surge. But the proposal will see opposition from some G-77 countries itself with Brazil and some other key nations that are losing their forests fast prefering to keep the forest sector out of CDM and demanding a new mechanism to deal with it.
For Clean Technology
"The only time that one may see industrialized country industry and developing world businesses speaking the same language will be when it comes to relaxing the regulations and conditions for carbon credits," a senior Indian official from Bali told the Times of India. At present, there are stringent conditions to be met before a project is allowed carbon certificatl!s. One key issue is of 'additionality'- proving that the clean technology project would have been unviable without the
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additional money selling credits generates. The developing world business wants such conditions to be less tight on their projects to earn their credits easy. They also want some environmental conditions to be eased, to include mega-hydropower projects and nuclear power to be accepted as carbon credit worthy. Though hydropower is accepted under UN but EU, the biggest consumer, does not accept carbon credits generated from such markets. The next 10 days would see parleys on this on the sidelines of the main meetings. "One key issue will be the future of the refrigerant gases in the CDM mechanism," another Indian official said. Some of the biggest credit generating projects have come from destruction of harmful refrigerant gases. But the mechanism at present allows for not only older existing facilities to be corrected using credit mechanism but also those businesses that will produce these harmful gasses in future to claim credits for fIxing their plants. TOI 15.11.2007 'VOLCANIC ERUPTION MAY HAVE WIPED
our DINOSAURS'
Study Based on Excavations made from Quarries in India New Delhi: It may have been a volcanic eruption and not so much of a meteor strike that could have wIped out the T-Rexes, Stegosaurs and Raptors from the face of the earth. Scientists are digging up proof to confirm that giant volcanic eruptions may have caused the mass dinosaur extinction between 63 million to 67 million years ago. Experts have long been debating on what caused the wipeout. Some believe it was an asteroid or comet impact which left a vast crater at Chicxulub on the coast of Mexico that resulted in the K-Tor CretaceousTertiary extinction event, which killed off all dinosaurs. Others contend that a series of colossal volcanic eruptions created the gigantic Deccan Traps lava beds in India, whose original extent may have covered as much as 1.5 million sq Ian, or more than twice the area of Texas. According to the latest fmdings, presented recently at the annual meeting of the Geological Society of America in Denver, Princeton University paleontologist Gerta Keller suggested the mass extinction happened at or just after the biggest phase of the Deccan eruptions, which spewed 80% of the lava found at the Deccan Traps. "It's the first time we can directly link the main phase of the Deccan Traps to mass extinction," Dr Keller said.
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Keller and colleagues focused on marine fossils excavated from quarries at Rajalunundry, India, near the Bay of Bengal, about 1,000 km southeast of the centre of the Deccan Traps near Mumbai. Specifically, they looked at the remains of microscopic shell-forming organisms known as foraminifera. Keller said, "Previous work had only narrowed the timing of the Deccan eruptions of the Deccan eruptions to within 300,000 to 500,000 years of the extinction event. We believe that before the mass extinction, most of the formainifera species were comparatively large, very tlahoyant, very speclialized, very ornate, with many chambers. These foraminifera were roughly 200 to 350 microns large or a fifth to a third of a millimetre long." She added, "When the environment changed, as it did around K-T, that prompted their extinction. The foraminifera that followed were extremely tiny, one-twentieth the size of the species before, with absolutely no omarnentation, just a few chambers." The researchers found that these simple foraminifera seemed to have popped up right after the man; phase of the Deccan volcanism. This, in turn, hints these eruptions came immediately before the mass extinction, and might have caused it. Keller stressed that these findings did not deny that an impact occurred around the K-T boundary, and noted that one or possibly several impacts may have had a hand in the mass extinction. The dinosaurs might have faced an unfortunate coincidence of a one-two punch of Deccan volcanism and then a hit from space, she explained. "We just show the Deccan eruptions might have had a significant impact," she added. TOI 16.8.2007 RUSSIA HOLDS N-DRILL OVER NORTH POLE Moscow: Russian strategic bombers on Tuesday began five days of exercises over the North Pole, marking the latest in a series of displays of Moscow's military muscle. The nuclear-capable bombers will practice firing cruise missiles, navigation in the polar region and aerial refuelling manoeuvres, the Russian air force said. The exercises come barely a week after Russian strategic Tu-95 bombers tlew over the Pacific to within a few hundred kilometres of the US military base on Guam-and, according to a Russian general, exchanged grins with US fighter pilots sent to intercept.
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They also follow recent attempts by Moscow to bolster Russia's territorial claims in the Arctic region. One Russian air force officer said he expected US interceptors would once again make their presence felt during this week's exercises. "It is a traditional practice for military pilots to see foreign pilots come up to meet them and say hello," he said. "The US are aware of our exercise," he said. Russia's long-range bombers have been involved in a number of other exercises recently. On July 20, Norway and UK scrambled its fighter planes after Norway detected Russian bombers flying over the North sea between Norway and UK. TOI 1.9.2007 INDIA TO WORK wrm CIllNA ONRECEDING IHMALAYAN GLACIERS New Delhi: Faced with the danger of receding Himalayan glaciers and its catastrophic effect on the ecology of the region, India has taken up the issue with China for a joint selution to the problem. "I had raised the issue with the Chinese president and it was agreed that there should be more discussions to work out a joint solution," Prime Minister Manmohan Singh said while intervening in the reply to a question in Rajya Sabha on Thursday. He said the melting of glaciers was an important issue because it could have a catastrophic effect on the ecology of not only the region but also the world. In response to a question about the exact nature of the danger faced by India due to shrinking of glaciers, minister of state for environment and forests Namo Narain Meena said, "The melting of glaciers will ultimately trigger more droughts, expand desertification and increase sand storms. Melting also threatens disruption of water supply as many rivers emanate from the Himalayas."
The move to hold talks with China comes as a change from India's earlier stance. India had declined to work with China, Nepal and Pakistan on Himalayan glaciology earlier owing to security concerns. But recent reports of the UN panel on climate change has made the government think twice on issues of data and knowledge sharing on glaciers. In the last meeting of the Pr-,'I's scientific group on climate change, the point about generation of data across the subcontinent and sharing of this data had been highlighted.
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While some preliminary work has been done on glaciers on the Indian side of the Himalayas, scientists recognise that the Indian glacial river systems-Ganga as well as Brahmaputra-are dependent on the glacial fonnations in Nepal and China as well.
TOI 3.8.2007 RUSSIA GOES UNDER SEA, CLAIMS N POLE Moscow: Members of Russia's parliament in a mini-submarine planted their country's flag 4 km below the North Pole at the climax of a mission to back up Russian claims to the region's mineral riches~~~ "The Mir-1 submarine successfully reached the bottom o{the Arctic Ocean... at a depth of 4,261 metres," veteran Arctic explorer and expedition leader Artur Chilingarov told the Vesti television channel. A metre-high flag, made of titanium so as not to rust, was deposited on the seabed, the ITAR-TASS news agency cited an expedition official as saying. Chilingarov was joined by fellow parliamentarian Vladimir Gruzdev and four others, three of whom followed in a second mini-submarine, which touched the seabed 4,302 metres below the surface, Vesti reported.
Miniature submarines from this Russian research vessel dived into the Arctic Ocean to plant a flag on the seabed under the North Pole
Billed as the first to reach the ocean floor under the North Pole, the expedition aims to establish that a section of seabed passing through the pole, known as the Lomonosov Ridge, is in fact an extension of Russia's landmass. "We must determine the border. The most northerly border of the Russian shelf," Chilingarov said in comments broadcast before the dive from the Akademik Fyodorov research ship leading the expedition. The voyage reflects growing international interest in the Arctic partly due to climate change, which is causing greater melting of the ice and making the area more accessible for research and economic activity.
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The US Geological Survey, a US government agency, said in a report earlier that some 25% of world oil reserves are believed to be located above the Arctic Circle. In 2001 Russia made a submission to a United Nations commission claiming sub-sea rights stretching to the pole. The current mission is looking for evidence to back up this claim. TOI 24.8.2007
TIME BOMB TICKS IN ARCTIC Race for the seabed could be an environmental disaster
Jeremy Rifkin If there were any lingering doubts as to how ill-prepared we are to face up to the reality of climate change, they were laid to rest this month when two Russian mini submarines dove two miles under the Arctic ice to the floor of the ocean, and planted a Russian flag made of titanium on the seabed. This fIrst manned mission to the ocean floor of the Arctic, which was carefully choreographed for a global television audience, was the ultimate geopolitical reality TV. Russian President Vladimir V Putin congratulated the aquanauts while the Russian government simultaneously announced its claim to nearly half of the floor of the Arctic Ocean. The Putin government claims that the seabed under the pole, known as the Lomonosov Ridge, is an extension of Russia's continental shelf, and therefore Russian territory. Not to be outdone, Canadian Prime Minister Stephen Harper hurriedly arranged a three-day visit to the Arctic to stake his country's claim to the region. Although in some respects the entire event appeared almost comical-a kind of late 19th century caricature of a colonial expedition - the intent was deadly serious. Geologists believe that 25 per cent of the earth's undiscovered oil and gas may be embedded within the rock underneath the Arctic Ocean. The oil giants are already scurrying to the front of the line, seeking contracts to exploit the vast potential of oil wealth under the Arctic ice. The oil company BP has recently established a partnership with Rosneft, the Russian state-owned oil company, to explore the region. Aside from Russia and Canada, three other countriesNorway, Denmark (Greenland is a Danish possession that reaches into the Arctic) and the United States-are all claiming the Arctic seabed as an extension of their continental shelves and, therefore, sovereign territory. Under the Law ofthe Sea Treaty, adopted in 1982, signatory nations can claim exclusive economic zones for commercial exploitation, up to
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200 miles out from their territorial waters. The US has never signed the . treaty, amidst concerns that other provisions of the treaty would undermine US sovereignty and political independence. Now, however, the sudden new interest in Arctic oil and gas has put a fIre under US legislators to ratify the treaty, lest it is edged out of the Arctic oil rush. What makes the whole development so utterly depressing is that the new interest in prospecting the Arctic subsoil and seabed for oil and gas is only now becoming possible because of climate change. For thousands of years, the fossil fuel deposits lay locked up under the ice and inaccessible. Now, global warming is melting away the Arctic ice, making possible, for the fIrst time, the commercial exploitation of the oil and gas deposits. Ironically, the very process of burning fossil fuels releases massive amounts of carbon dioxide and forces an increase in the earth's temperature, which in turn, melts the Arctic ice, making available even more oil and gas for energy. The burning of these potential new oil and gas frods will further increase CO2 emissions in the coming decades, depleting the Arctic ice even more quickly.
But the story doesn't stop here. There is a far more dangerous aspect to the unfolding drama in the Arctic. While governments and oil giants are hoping the Arctic ice will melt quickly to allow them access to the world's last treasure trove of oil and gas, climatologists are deeply worried about something else buried under the ice, that if unearthed, could wreak havoc on the earth's biosphere, with dire consequences for human life. Much of the Siberian sub-Arctic region, an area the size of France and Germany combined, is a vast frozen peat bog. Before the previous
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ice age, the area was mostly grassland, teeming with wildlife. The coming of the glaciers entombed the organic matter below the permafrost, where it has remained ever since. While the surface of Siberia is largely barren, there is as much organic matter buried underneath the permafrost as there is in all of the world's tropical rainforests. Now, with the earth's temperature steadily rising because of CO 2 and other global warming gas emissions, the permafrost is melting, both on land and along the seabeds. If the thawing of the permafrost is in the presence of oxygen on land, the decomposing of organic matter leads to the production of CO 2 • If the permafrost thaws along lake shelves, in the absence of oxygen the decomposing matter release methane into the atmosphere. Methane is the most potent of the greenhouse gases, with a greenhouse effect that is 23 times greater than that of CO 2. Researchers are beginning to warn of a tipping point sometime within this century when the release of carbon dioxide and methane cou' create an uncontrollable feedback effect, dramatically warming the atmosphere, which will, in turn, warm the land, lakes and seabed, further melting the permafrost and releasing more carbon dioxide and methane into the atmc phere. Once that threshold is reached, there is nothing human beings can do, of a technological or political nature, to stop the runaway feedback effect. Scientists suspect that similar events have occurred in the ancient past, between glacial and interglacial periods. Katy Walter of the Institute of Arctic Biology at the University of Alaska in Fairbanks and her research team calls the permafrost melt a giant "ticking time bomb". A global tragedy monumental proportions is unfolding at top of the world, and the human race is all oblivious to what's happening.
The writer is president, The Foundation Economic Trends, Washington, DC. TOI 13.9.2007 MlNIICE AGE DIDN'T KILL NEANDERIHALS They were either Slaughtered by Homo Sapiens or Intermingled with
them: Study Paris: The great whodunnit of palaeontology has been given a new twist with findings that the Neanderthals were in all likelihood not killed off by a mini-Ice Age, as some authorities contend. Neanderthals, smaller and squatter than Homo sapiens, lived in parts of Europe, Central Asia and the Middle East for around 170,000 years.
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One theory is that the Neanderthals were wiped out by a sudde~ cold snap. Alone, their numbers depleted, the Neanderthals eked out their final moments in caves in modem-day Spain and Gibraltar, goes this hypothesis. One of the problems of exploring the Neanderthal saga is to get an accurate date for when all this may have happened. The main dating technique is to test fossils for levels of a background isotope in the environment, carbon 14. Researchers led by Polychronis Tzedakis at the University of Leeds and the University of the Aegean, Greece, sought a different yardstick: one based on climate rather than chronology. They found one in a sedimentary core drilled in the seabed of Cariaco Basin, Venezuela, in which records of past climate events can be related directly to radiocarbon years.
Visitors at the Museum for Prehistory in Eyzies-de-Tayac, France, look at an attempted reconstruction of a Neanderthal man and boy.
The team probed three dates that have been variously proposed for the end of the Neanderthals. The evidence from these days comes from artifacts found in Gorham's Cave in Gibraltar, where Neanderthals interspersed periods of residence with modem humans. The two most-commonly proposed dates are 32,000 years, 28,000 years and 24,000 years ago. That coincided with Earth's last "glacial era", a term that despite its name also included periods of instability, warm and cold alike. The most redoubtable of these periods were so-called Heinrich Events, when the balmy North Atlantic drift, which supplies Western Europe with warmth despite its high northerly latitude, abmptly shut down, plunging the continent into deep cold.
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But none of the three proposed dates chime with a Heinrich Event, says Tzedakis, whose team's research is published on Thursday by the weekly British journal Nature. "We can eliminate catastrophic climate change as the cause of the Neanderthals' extinction," he said. But then what-or who-killed them? Two rival theories are out there. One says that the Neanderthals were slaughtered by modem humans. Another says that Neanderthals· and modem Man intermingled and even interbred. And, the distinct Neanderthal lineage petered out.
TOI 27.11.2007 UN CLlMAlE CIRCUS ROLLS IN ON CO2 CWUD Bali Summit will emit Equivalent of 100,000 Tonnes Extra CO2 Nicola Smith & Jonathan Leake It has been billed as the summit that could help save the planet, but the latest UN climate change conference on the island of Bali has itself become a major contributor to global warming. Calculations suggest flying the 15,000 politicians, civil servants, green campaigners and television crews into Indonesia will generate the equivalent of 100,000 tonnes of extra CO2 , That is similar to the entire annual emissions of the African state of Chad. The preparations are acquiring the feel of a huge party, with the Indonesian government seeing it as a chance to promote Bali as a tourist destination after the 2002 terrorist bombings that killed 202 people. When it was first CODI' - .;d, only a few thousand politicians, civil servants and environmentahsts were expected to attend the conference. The meeting, which runs from December 3 to 14, aims to create the framework for a successor to the Kyoto treaty on reducing global greenhouse gas emissions, which expires in 2012. However, climate change's growing political importance has led to a surge in interest in the conference,_ which is being held in the luxury holiday resort of Nusa Dua on Bali's palm-fringed southern coast. Attendees are expected to include celebrities like Leonardo DiCaprio, the actor and Arnold Schwarzenegger, governor of California. Many are merely "observers" who have no fonnal role to play in the talks, including 20 MEPs and 18 assistants whose itinerary includes a day-long trip to the idyllic fishing and surfmg village of Serangan. The UN has also recently received thousands of new registrations from groups campaigning for the environment or fighting against poverty
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WWF, one of the largest, is sending more than 32 staff to the meeting. Thousands more are coming from businesses, especially the burgeoning carbon trading sector. Indonesian officials say the fmal tally could reach 20,000-and fear it could stretch the resort's infrastructure to the limit. About 90% of the emissions will be generated by delegates flying thousands of miles to Bali, with the rest coming from the facilities they will be using. Chris Goodall, a carbon emissions expert, estimated each person flying to Bali would, on average, generate the equivalent of 6.4 tonnes of CO2 • If 15,000 people attend, this adds up to 96,000 tonnes of CO2 • To this must be added about 10,000 tonnes of CO2 from the conference venue and hotels - a total of 106,000 tonnes.
Phil Woolas, British junior environment minister, is embarrassed by the opulence of such gatherengs. "It's like a circus," he said. "It's not just Bali. There are now more than 500 environmental treaties and conventions taking place around the world. It's a morass of Byzantine proportions. The UN oversees world governance on these issues and we urgently need to streamline it." TOI 13.11.2007
FASfER, SMAILERCIDPLAUNCHED San Francisco: Intel Corp, the world's biggest microchip maker, unveiled fast new processors on Sunday made with new techniques that can etch circuitry nearly 200 times smaller than a red blood cell. The chips are the first in the world to be mass-produced with a 45nanometer process, about one-third smaller than current 65-nanometer technology. A nanometer is one-billionth of a meter. "Across all segments we're increasing performance and increasing energy efficiency" said Tom Kilroy, general manager of Intel's enterprise group. Known by the project name Penryn, the chips hold little in the way of fundamental design advances but are an important step in continuing the industry's track record of delivering chips that get smaller and faster every two years or so. They use a new kind of transistor-the basic building block of microchips-that Intel unveiled earlier this year in what was hailed as one of the industry's biggest advances in four decades. Penryn is the "tick" in Intel's "tick-tock" strategy of shrinking an existing chip design to a smaller size, then following up the next year with an all-new blueprint, known as a microarchitecture.
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"They are taking a successful product and making it smaller, and in the process of making it smaller, it gets faster," said Nathan Brookwood, principal analyst of consultant Insight 64. Brookwood said he reckoned the new chips, to be sold under Intel's Xeon and Core 2 brands, would be able to run most software up to 15 % faster. The 45 nanometer shift is also important to Intel because it means the company can make more chips from a single platter of silicon, boosting productivity and helping recoup investment on factories, which cost about $3 billion to build. TOI 29.9.2007
RUSSIA TO HAVE WORLD'S FIRST FLOATING NUCLEAR PLANT Moscow: The world's fIrs,t floating nuclear power plant will be commissioned in 2011 in Russia's Arctic, the governor of the Arkhangelsk ' Region said. "The construction of the fIrst such power unit with 70 MW capacity was started this year and should be completed by 2010. The plant is most likely to operate in Severodvinsk (in Russia's Arkhangelsk region). Its launch is planned for 2011," Nikolai Kiselyov said. "A floating nuclear power plant is a new product on the global market, and I hope it will be in demand," he said. Russia started building the plant at the Arctic port of Severodvinsk in April, and is expected to build six more nuclear power plants of its kind within a decade. Earlier, a Russian nuclear offIcial said over 20 countries were interested in buying the such plants. They are expected to be widely used in remote regions with power shortfalls and also in the implementation of projects requiring stand-alone and uninterrupted electricity supplies in the absence of a developed power grid. INDIA, A SOFIWARE DEVEWPMENT HUB As India emerges into a global and economic player, it has become an important hub for offshore software development, as well as a top destination for overseas companies to outsource business processes such as technical help desks, payroll management, and legal and design services. Bangalore, touted as the Silicon Valley of India, is home to software giants Wipro Technologies and Infosys Technologies Ltd, and has a budding biotech sector.
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Many expect a new wave of outsourcing, including gaming development and health-care services, and Indian companies will be at the forefront of these emerging trends. The software sector was pioneered by flagship Tata Consultancy Services Ltd in the late 1960s.-The software sector saw a 33% rise in exports to $31.4 billion for the year to March 2007, according to the National Association of Software and Service Companies (Nasscom). It is expec4f
