SEG Newsletter 100 2015 January

Advancing Science and Discovery 0

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Footprints: Hydrothermal Alteration and Geochemical Dispersion Around Porphyry Copper Deposits Scott Halley, Mineral Mapping Pty Ltd., 24 Webb Street, Rossmoyne, WA 6148, Australia, John H. Dilles, Oregon State University, College of Earth, Oceanic and Atmospheric Sciences,104 CEOAS Administrative Building, Corvallis, OR 97331, United States, and Richard M. Tosdal,† PicachoEx LLC, 21 Quince Mill Court, North Potomac, MD 20878, United States

ABSTRACT

a.) Hydrothermal alteration assemblages Illite-chl-smect -relic fspar

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phengitic musc-chlrelic fspar

atic gm -ma

Corresponding author: e-mail, [email protected]

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Cp-Py

Cp±Bn

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Porphyry and related epithermal Au-Ag ores are the world’s most important ore deposits outside of iron and aluminum mines, produce most of the Cu and Mo, and are the largest producers of Au and Ag globally. It has been known for over a century that metals in porphyry Cu deposits are zoned, with a central to page 12 . . .

ARGILLIC

fluids

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INTRODUCTION

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Whole-rock lithogeochemical analyses combined with short-wave infrared (SWIR) spectroscopy provide a rapid and cost-effective method for prospecting for porphyry-type hydrothermal systems. Lithogeochemistry detects trace metals to average crustal abundance levels and allows vectoring via gradients of chalcophile and lithophile elements transported by magmatic-hydrothermal ore and external circulating fluids that are dispersed and trapped in altered rocks. Of particular use are alkalis in sericite and metals such as Mo, W, Se, Te, Bi, As, and Sb, which form stable oxides that remain in weathered rocks and soils. SWIR mapping of shifts in the 2,200-nm Al-OH absorption feature in sericite define paleofluid pH gradients useful for vectoring toward the center of the buoyant metalbearing magmatic-hydrothermal plume.

SODICCALCIC granite plag-act±epid porphyry dikes

LATE INTERMEDIATE ARGILLIC magmatic smect±Illite±kaol±chl fluids & relic feldspar Cu > 0.2wt% (±Mo±Au)

FIGURE 1. a.) Vertical cross section of a typical porphyry Cu deposit showing distribution of hydrothermal alteration and sulfide minerals. Also shown are generalized contours of the 2,200-nm peak measured in SWIR instruments.

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S E G N E W S L E T T E R 3

No 100 • JANUARY 2015

Contents NEWSLETTER Nº 100 — JANUARY 2015 Executive Editor................... Brian G. Hoal Technical Editor.................. Shaun Barker Views Editors............ Jeffrey Hedenquist John Thompson Production Editor................. Chris Brandt News Editor.......................... Alice Bouley Graphic Design    & Advertising........... Vivian Smallwood Announcements...........Christine Horrigan Society of Economic Geologists, Inc. 7811 Shaffer Parkway Littleton, CO 80127-3732 USA Tel. +1.720.981.7882 • Fax +1.720.981.7874 E-mail: [email protected]

www.segweb.org Feature articles are peer reviewed before they are accepted for publication. Please submit material to the Technical Editor. Tel. +1.720.981.7882 Fax +1.720.981.7874 E-mail: [email protected] The SEG Newsletter is published quarterly in January, April, July, and October by the Society of Economic Geologists, Littleton, Colorado, exclusively for members of the Society. Opinions expressed herein are those of the writers and do not necessarily represent official positions of the Society of Economic Geologists. When quoting material from the SEG ­ Newsletter please credit both author and publication. © 2015 The Society of Economic Geologists, Inc. Printed by MODERN LITHO–PRINT CO. Jefferson City, Missouri SEG Newsletter non-receipt claims must be made within four (4) months [nine (9) months outside the U.S.A.] of the date of publication in ­order to be filled without charge.

— FOR CONTRIBUTORS — The SEG Newsletter is published for the benefit of the worldwide membership of the Society of Economic Geologists. We invite news items and short articles on topics of potential interest to the membership. If you have questions on submittal of material, please call the SEG office at +1.720.981.7882 or send details by FAX to +1.720.981.7874; by e-mail to [email protected]. Format: E-mailed news items should be 5 Mb maximum. Send to [email protected]. Short items may be faxed. Please include your name and contact information for verification purposes. Please e-mail Chris Brandt at the above address if you have questions. Advertising: Paid advertising is solicited to help offset publication and mailing costs; for rates, contact [email protected].

DEADLINE FOR NEWSLETTER #101:

February 28, 2015

F E AT U R E A R T I C L E

1 Footprints: Hydrothermal Alteration and Geochemical Dispersion Around Porphyry Copper Deposits

NEWSLETTER COLUMNS

4 5 8 9

From the Executive Director: 100th Issue of the SEG Newsletter From the Executive Director: SEG Council Actions Presidential Perspective: Consolidation, Growth and Challenges… SEGF Presidential Perspective: Threads of Continuity— Keeping the Fabric of Our Profession Strong

6 10-11 18-19 20-21 22 22 24 26 27 27 29-40

Society of Economic Geologists Awards 2014–2015 Contributions – SEG, SEG Foundation, and SEG Canada Foundation SEG 2014 Conference, Keystone, Colorado, USA SEG Awards Ceremony at the SEG 2014 Conference Announcing the SEG 2015 Distinguished Lecturer Announcing the SEG 2015 Traveling Lecturers Presidential Address: In Praise of Life-Long Learning 2014 SEG Thayer Lindsley Visiting Lecture Tour Field Trip to High Sulfidation Epithermal Gold Deposits in Southern Peru SEG at the XVII Peruvian Geological Congress in Lima, Peru SEG 2015 Conference—World-Class Ore Deposits: Discovery to Recovery

41 42 42 42 43 44-45

SEG Student Chapter Grant Recipients for 2014 Student Chapter Support Available: SEG Stewart R. Wallace Fund Student Member and Chapter Announcements Graduate Student Fellowships Available for 2015 Student Research Grants Available for 2015 Student Chapter Report Summaries

SEG NEWS

SEG STUDENT NEWS



E X P L O R AT I O N R E V I E W S

47 – Alaska  •  47 – Australasia  •  48 – Northern Eurasia  •  49 – Contiguous United States

MEMBERSHIP

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ANNOUNCEMENTS

28 2015 GSN Symposium & SEG Forum, Reno/Sparks, Nevada 46 World-Class Tin-Silver Deposits Field Trip, Oruro, Bolivia 56 UNESCO-SEG-SGA Latin American Metallogeny Course 2015, Campinas, Brazil 57 ProExplo 2015, Lima, Peru 62 3rd Symposium on Igneous Petrology and Ore Deposits, Rio Negro Province, Argentina 62 4th SGA-SEG-UNESCO-IUGS Short Course, Addis Ababa, Ethiopia 62 SRK & University of Toronto Workshop, Toronto, Canada 67 Geofacets from Elsevier – Sign Up Today! (inside back cover) 68 PACRIM 2015 & SEG Post-Conference Workshop, Hong Kong, China (back cover)

S E G E D U C AT I O N & T R A I N I N G C U R R I C U L U M

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SEG Membership: Candidates and New Fellows, Members, and Student Members SEG 2015 Officers and Committees SEG Announcements and Deadlines Personal Notes and News

Preliminary 2015 Education & Training Curriculum Geology of Gold Deposits Short Course, University of Cape Town, Rondebosch, South Africa SEG at PDAC 2015: Geology of Copper: Porphyry Copper, IOGC and Sedimentary Rock-Hosted Stratiform Copper Deposits, Toronto, Canada SEG at PDAC 2015: Structural Geology of Gold and Copper Deposits, with Emphasis on Ores in Continental Margin Tectonic Settings, Toronto, Canada SEG at GAC/MAC/AGU/CGU 2015 Meeting: Short Course on Geology of GraniteGreenstone Terranes and Their Mineral Deposits, Montreal, Canada Geology and Geochemistry of Gold Deposits Workshop at SGA, Nancy, France

CALENDAR OF EVENTS 66 Calendar

ADVERTISERS —  2 67 49 41 48 41 64

Actlabs, Ltd. (inside front cover) ALS Minerals (inside back cover) Anzman, Joseph R. AVRUPA Minerals Condor Consulting, Inc. CSM/Namibia Field Trip de Haller & Schmidt

11 EGRU 25 Laravie, Joseph A. 57 Laurentian University 46 NBMG/Job Opening  2 ORE (inside front cover)  7 Parkhill, Thomas A. 64 Petrographic Consultants Intl.

 7 49   2 25 57

Recursos del Caribe, S.A. Resource Geosciences de Mexico SGS (inside front cover) Shea Clark Smith Zonge Engineering & Research

SEG NEWSLETTER

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No 100 • JANUARY 2015

  FROM THE EXECUTIVE DIRECTOR

100th Issue of the SEG Newsletter refers to the formative role played by Expanding in size from a total of 20 to the Publications Committee the previmore than 60 pages in 100 issues over a ous fall. Prior to the quarterly Newsletter, span of 25 years, the growth of the SEG the journal had published all the SociNewsletter reflects the vigorous evolution ety news in its back pages—typically a of the Society during that same period. dozen or more pages on such topics as Those leaders who saw the need to give new member/fellow listings, field trip a voice to the activities of its memberreports, officer biographies, regional ship obviously made a wise decision in vice-president reports, various notes and creating what is cited by some as the news, announcements, publimost popular publicacation order forms, advertisetion of the SEG. Since 2010, all issues of the ments for publications and Issue Number 1 of SEG Newsletter have been meetings, and a calendar of the SEG Newsletter was readily available as PDF events. published in April files on the SEG website. The first issue of the SEG 1990. This publicaNewsletter provides an interesttion was set to coining retrospective through the columns cide with the beginning of the Society of the officers noted above and, to make “year” (changed to a calendar year startup the 20 pages of content, includes a ing January 2002) and the beginning number of interesting deviations from of the Presidential term of G. Arthur the Society content typically includ(Art) Barber, with Walden (Wally) P. ed in the journal. Among them are a Pratt as the first Newsletter Editor, Jack membership survey compiled by an E. Murphy serving as the “Executive ad hoc committee (chaired by John C. Secretary,” Donald M. Davidson, Jr. as Wilson) to “improve the flow of quality Treasurer, and Don Everhart as President field-oriented ore deposit papers to Ecoof the SEG Foundation. The need for a nomic Geology and other (possibly new) newsletter to supplement the journal, SEG publications,” a member’s forum, Economic Geology, is noted by Editor a position paper on geologic mapping, Pratt in his inaugural column, where he student chapter activities (six student chapters existed in 1990, all in North America), an exploration review, and a more comprehensive feature on upcoming meetings.

Advancing Science and Discovery NEWSLETTER

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NEWSLETTER

Advancing Science Science and and Discovery Discovery Advancing

OCTOBER 2014

www.segweb.org

NUMBER 99

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So what has changed? On the face of it, not a great deal in terms of structure and content—the basic Brian G. Hoal elements are still easily recognizSEG Executive Director able in the current and Editor issue. Arguably the biggest change has been the introduction of a widely read technical feature or lead article and the growth in content and color illustrations. Contrast the Newsletter banners over the years in the graphic below and you acquire some sense of the evolution to the current issue, Number 100. The introduction of all-color issues has been very popular with readers and the availability of digital format equally so, given the ease of electronic searches. Since 2010, all issues of the SEG Newsletter have been readily available as PDF files on the SEG website. Much has happened to the Society in 25 years since the introduction of the first Newsletter and SEG now has a presence that was probably difficult to envision, even as recently as 1990. Membership has tripled since then and the number of student chapters has grown by well over a 1,000%, so many more contributions to the Newsletter have flowed in from all over the world to generate issues frequently three times the size of that first one. With the need to limit print and distribution costs, an electronic Newsletter supplement of the Exploration Reviews was initiated in 2010. Many of the key changes were effected through shifting production of the publication from volunteers to a professional staff at the SEG offices in Littleton. But the key content still is submitted by volunteers who continue to provide “ore for the mill” in the form of new and exciting events and developments in the field of economic geology. The SEG Newsletter has established itself as a key benefit of membership for many and that is the highest compliment that we could hope for. Thank you to all our readers and contributors for your valuable and ongoing support. 1



No 100 • JANUARY 2015

S E G N E W S L E T T E R 5

  FROM THE EXECUTIVE DIRECTOR

SEG Council Actions

Keystone, Colorado, USA – September 26, 2014 The SEG Council held a regularly scheduled meeting in Castle Peak I & II, Keystone Convention Centre in Keystone, Colorado, USA. Members of the Council present were J.A. Kinnaird (Chair), R.M. Baumgartner, G.M. Brown, F.I. de Azevedo, R.J. Goldfarb, D.J. Hall, B.G. Hoal, K.D. Kelley, H.J. Noyes, F. Robert, M. Soylu, and A.T. Swarthout (President of Foundation). C.A. Horrigan (SEG Executive Assistant) and N. Fayol also attended. Apologies were received from A. Arribas, R., G.G. Carlson (President of Canada Foundation), J. Cline, J. Mao, T.C. McCuaig, T. Monecke, and G. Olivo. President Kinnaird called the meeting to order at 1:00 p.m. After establishing that there was a quorum, President Kinnaird asked attendees to briefly introduce themselves. The following actions were taken at the meeting: n Approved a motion from F. Robert to accept the minutes of the meeting held on March 1, 2014. n Accepted the verbal report of the President in which she noted that she had recently visited staff at the Littleton office and considered the organization to be doing well. She further summarized a number of highlights including a membership that was holding strong at 7,000 despite a weak industry and a significant increase in the number of student chapters to over 80. Although students continued to make up 20% of the membership, recent graduates would receive a discount in their membership dues of close to 50% to encourage retention. Traveling lecturer programs remained active throughout the world and educational courses and field trips formed an important part of SEG’s visibility. The Keystone conference underscored SEG’s success at a challenging time in our industry and the level of participation by sponsors and attendees was exceptional. n Approved a motion from Swarthout to ratify the following actions taken by the Executive Committee since its meeting on February 28, 2014: — Approved Fellowship List No. 14-01 on March 6, 2014, thereby

admitting the following 26 candidates to SEG Fellowship: John F.W. Bowles, David P. Braxton, Sebastiao G. Carvalho, Alain Chauvet, Jason K. Dunning, Enrique Garay, Paul S. Heithersay, Catherine J. Hickson, Nigel M. Kelly, James P. Llorca, Alejandro L. Ly, Gail A. Mahood, Maria I. Marín-Cerón, David R. Miller, Andrea Mindszenty, Michael S.J. Mlynarczyk, Clay E. Postlethwaite, Stephen G. Redak, Patrick B. Redmond, Karl J. Roa, Shawn A. Ryan, Martiya Sadeghi, Gilbert Stein, Joao Batista Guimarães Teixeira, John V. Tiberindwa, and Bradley A. Wake. — Approved on March 20, 2014, the draft Executive Committee minutes for the February 28, 2014, meeting held at the Radisson Admiral Harbourfront Hotel in Toronto, Canada. — Approved Fellowship List No. 14-02 on June 2, 2014, thereby admitting the following 15 candidates to SEG Fellowship: Omer Albayrak, Marc Bardoux, Fletcher Bourke, William R. Brown, Cengiz Y. Demirci, Garth Earls, Matthew Field, John N. Lauderdale, Anthony A. Longo, Matthew J. McCarthy, Russell M. Meares, Eric Roth, Jenny Skoog, Alan J. Wainwright, and James A. Walker. — Recommended on August 10, 2014, that Council approve the nomination of the following members to Honorary Fellow status: John P. Hunt and Robert O. Fournier. — Approved Fellowship List No. 14-03 on September 12, 2014, thereby admitting the following 15 candidates to SEG Fellowship: Serdar Akca, Colin T. Barnett, Frances Cooper, Carla Dimalanta, Guillermo Gastelum-Morales, John M. Hanchar, James M. Logan, Dan Marshall, Aoife M. McGrath, Vasileios Melfos, Andrew J. Rowe, Friedrich Speidel, Justin J.W. Van Der Toorn, Peter J.M. Van Maastrigt, and Baojin Zhao. And the following actions taken by the Council since its meeting on March 1, 2014:

— Approved on March 1, 2014, the following Student Chapter applications as recommended by the Student Affairs Committee: Stanford University, California, USA (new chapter); Imperial College of London, United Kingdom (reactivated chapter); and Queen’s University, Kingston, Canada (reactivated chapter). — Approved on April 4, 2014, the draft Council minutes for the March 1, 2014, meeting held at the Radisson Admiral Harbourfront Hotel in Toronto, Canada. — Approved on April 29, 2014, the following Student Chapter applications as recommended by the Student Affairs Committee: (SFU) Simon Fraser University, BC, Canada and (CSM-Exeter) Camborne School of Mines, University of Exeter, UK. — Approved on July 2, 2014, the Nominating Committee’s slate of candidates to take office in the period 2015-2017: Robert P. Foster, 2015 President-Elect; A. James Macdonald, 2015-2017 Vice President for Regional Affairs; Howard C. Golden, Robert P. Moritz, and Brian G. Rusk, 2015-2017, Councilors. n Passed a motion from de Azevedo accepting the report of the Foundation President, noting the proposed candidates for the 2015-2019 Foundation Board of Trustees: Jones Belther (Brazil), Jonathan M.A. Hronsky (Australia), and Raymond R. Jannas (Chile). This slate required a majority vote of the Councilors (the members of SEG Foundation) and this condition was met. Council further noted that John Black and David Kelley would become Foundation President and Vice President, respectively, in 2015. Andrew Swarthout would become Past President and Ruth Carraher continue as Secretary. Swarthout thanked all the Trustees for their service and recognized Donald Birak’s strong efforts on behalf of the Foundation as Chair of the Fundraising Committee. n Passed a motion from to page 6 . . . Swarthout accepting

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No 100 • JANUARY 2015

SEG Council Actions — Keystone, Colorado — September 26, 2014 (continued)

the report of the Executive Director. Much of this report would be published in the January issue of the SEG Newsletter. n Passed a motion from Robert to approve the Treasurer’s Report on financials for the period January 1 to July 31, 2014, and the 2015 budget proposed by the Budget Committee. The Treasurer noted that the Society and Foundation were in sound financial condition. n Passed a motion from Baumgartner to ratify the Investment Committee membership for 2015 as follows: C. Herald (Chair), D. Baker, D. Birak, R. Hall, B. Suchomel, H. Noyes, and B. Hoal. n Passed a motion from Soylu accepting the report of the Chair of the Publications Board, Goldfarb. Noted that the print journal dues would be slightly higher in 2015 to cover shipping mainly, the journal was being published in a timely manner, and fee-based open access was now being offered to all authors. Two new publications had been released since the previous report by the Chair in Toronto, and most SEG publications are being released as e-books through GeoScienceWorld. Two Publication Board members, Stuart Simmons and Zhaoshan Chang, had agreed to extend their terms of office, while a replacement for one other, John Thompson, would be sought. Several

new publications were in the pipeline, including volumes on rare earth and critical elements, diamonds, and ore deposits of China. The special publication associated with the Keystone conference would be released at the meeting. n Noted the report of the Vice President for Regional Affairs, Y. Watanabe, as presented by the Executive Director, and passed the following resolutions: — Approved a new Regional Vice President for Europe, Jens Gutzmer, to start his 3-year term on January 1, 2015. This nomination was received from James Macdonald (VP Regional Affairs 2015-2017) and motion duly made by Kinnaird. — Approved, on a motion from Robert, the subcommittee (Chair: D.L. Huston) recommendation of Andreas Audétat (F 08), Bayerisches Geoinstitut, Germany as the 2015 International Exchange Lecturer. Topics for lecturing include geochemistry of high temperature metal transport in porphyry and related deposits. — Approved, on a motion from Kinnaird, the subcommittee (Chair: B. Rusk) recommendation of Karen Kelley (F 81), US Geological Survey, USA, as the 2015 Thayer Lindsley Visiting Lecturer. — On a motion from Robert, asked that the subcommittee (Chair: Watanabe) tasked with

Society of Economic Geologists Awards 2014–2015 SEG R.A.F. Penrose Gold Medal for 2014

James M. Franklin (Franklin Geosciences Ltd, Canada)

SEG Silver Medal for 2014

Stuart F. Simmons (Hot Solutions Ltd, New Zealand and Energy and Geoscience Institute, University of Utah, USA)

SEG Ralph W. Marsden Award for 2014

Mark D. Hannington (University of Ottawa, Canada)

SEG Waldemar Lindgren Award for 2014

Simon M. Jowitt (Monash University, Australia)

SEG Distinguished Lecturer for 2015

Sarah-Jane Barnes (Université du Québec à Chicoutimi, Canada)

SEG International Exchange Lecturer for 2015

Andreas Audétat (Bayerisches Geoinstitut, Germany)

SEG Thayer Lindsley Visiting Lecturer for 2015

Karen D. Kelley (US Geological Survey, USA)

SEG Regional Vice President Lecturer for 2015

Roy McG. Miller (Consulting Geologist, Namibia)

SEG Honorary Fellow for 2015

Robert O. Fournier (Retired, USA)

SEG Honorary Fellow for 2015

John P. Hunt (Hunt Exploration, Inc., USA)

recommending a Regional Vice President Lecturer provide a further candidate and an alternate choice for consideration by the Council. n On a motion from de Azevedo, approved the committee (Chair, S. Gleeson) recommendation of Sarah-Jane Barnes (F 93), Universite du Quebec a Chicoutimi, Canada as the 2015 SEG Distinguished Lecturer. Barnes has made a significant contribution in the field of Ni-Cu-PGE deposits. n On a motion from Baumgartner, approved the Awards Committee (Chair, J. Cline) recommendations as follows: — Penrose Gold Medal for 2014 to James M. Franklin (SF 85), Franklin Geosciences Ltd., Canada — SEG Silver Medal for 2014 to Stuart F. Simmons (F 85), Energy & Geoscience Institute, USA — Ralph W. Marsden Award for 2014 to Mark D. Hannington (FL 91), University of Ottawa, Canada n Passed a motion from Robert to approve the recommendation of the committee (Chair, M.D. Barton) that Simon M. Jowitt (M 08), Monash University, Australia, receive the 2014 Waldemar Lindgren Award. n Discussed the SEG Honorary Fellow Committee Report from Arribas, R. and, on a motion from Soylu, re-affirmed Honorary Fellowships for the following nominees: — Robert O. Fournier (SF 69), California, USA — John P. Hunt (SF 71), California, USA SEG Honorary Fellows are senior economic geologists recognized for extraordinary contributions, particularly those who have not already received an SEG Medal or Award. n On a motion from de Azevedo, approved the following nominees for committee vacancies as recommended by the Committee on Committees (Chair, R.M. Tosdal): — Distinguished Lecturer Committee: Zhaoshan Chang (F 04, Australia) and Kalin Kouzmanov (M 08, Switzerland) — Fellowship Admissions Committee: Huayong Chen (F 09, China) and David Selby (F 01, UK)



No 100 • JANUARY 2015

— Lindgren Award Committee: Peter Hollings (F 04, Canada) and Alan Wilson (F 95, Australia) — Student Affairs Committee: John Clifford (F 89, Ireland) and Mega Rosana (F 99, Indonesia) — Traveling Lecturers Committee: David Braxton (F 99, UK), Alan Galley (F 92, Canada), and Ilkay Kus¸cu (F 09, Turkey) n Passed a motion from Soylu to accept the report of the Student Affairs Committee presented by the Chair, R. Baumgartner, with the following specific action: — Approval of two new SEG Student Chapters: Universidad Autónoma de Guerrero, Mexico and Aristotle University Thessaloniki, Greece. With the above approval, there are now 83 Student Chapters located in 27 countries; the SEG Stewart R. Wallace Fund distributed $25,794 to 25 Student Chapters as part of Round 1 (of 2) funding. n Passed a motion from Brown to accept the SEG Students’ Committee annual report as presented by the Chair, N. Fayol. The role of Student Chapter advisors in communicating with and supporting students was emphasized. Council requested that Cam McCuaig provide an update on the status of the student-proposed exploration geology contest. n Thanked Bart Suchomel, Chair of the SEG 2014 Conference Organizing Committee, for providing a very positive status report on the conference “Building Exploration Capability for the 21st Century” scheduled to start on September 27th. The following information was noteworthy: — There were 810 attendees registered to date, including164 students. Sponsorship enabled support of more than 100 students. Exhibit booths were sold out.

S E G N E W S L E T T E R 7

— The technical program was made up of 74 talks (22 of these invited) and nearly 200 posters. — Field trip registrants numbered almost 160, with a similar number of workshop attendees. — An SEG Special Publication would accompany the conference and be released on site. n Accepted a report from Bruce Gemmell, Chair of the SEG 2015 Conference Organizing Committee, on the status of the conference “World-Class Ore Deposits: Discovery to Recovery” to be held jointly with CODES in Hobart, Tasmania. Contracts have been signed with the meeting planner and venue hotel, and a sponsorship-exhibition prospectus is now available. The technical program is well advanced and workshops and field trips are being finalized. The meeting planner, Leesa McDermott, was in attendance. n Accepted a report from Mesut Soylu, Chair of the SEG 2016 Conference Organizing Committee, on the status of the conference “Tethyan Tectonics and Metallogeny” to be held jointly with the Turkish Association of Economic Geologists (TAEG) in Izmir, Turkey. An agreement is in place between the two societies and the organizing committee and subcommittees are close to being finalized. A contract with the meeting planner, ZED, is currently under legal review and an onsite visit by SEG to the conference venue is in the planning stage. n Accepted, on a motion from Baumgartner, the report of the Program Committee (Chair A. Arribas, R.) as presented by the Executive Director. It was noted that many of the events listed through 2018 would be considered in more detail by the Education and Training Committee. n Passed a motion from Swarthout to accept the Education and Training

Committee Report as compiled by Elizabeth Holley, Program Coordinator, and presented by Robert, Chair. The following points were noted: — Thirteen short courses, four workshops, and twelve field trips make up the 2014 program. — A 2014 course brochure is available for download on the SEG website. — A catalog of all courses planned for 2015 is now available. — A meeting of the Education and Training Committee is scheduled to take place at Keystone and this will focus on further development of the committee’s “roadmap” including the development of an Economic Geology 101 course. n Discussed the following issues under Other Business: — The opportunity for closer alignment between the Society, SEG Foundation and Canada Foundation based on a favorable compliance review by PricewaterhouseCoopers in Canada. — An updated proposal for a joint SEG-GSA Economic Geology Field Program was received from GSA. Council affirmed that timing of implementation would be key given the need for industry funding and that students outside North America should be able to participate. — The issue of young graduates struggling in an industry downturn was noted by de Azevedo. Career advice and discussion in this regard was becoming a regular topic on the SEG LinkedIn Group and Council members were advised to participate as appropriate. n Agreed to schedule the next meeting of the Council on Saturday February 28, 2015, at the Radisson Admiral Harbourfront in Toronto. n Adjourned the meeting at 4:25 p.m. on a motion from Kinnaird. 1

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SEG NEWSLETTER

No 100 • JANUARY 2015

PRESIDENTIAL PERSPECTIVE

Consolidation, Growth and Challenges… During the past year as President-Elect, in the last 2 to 3 years, with strong I have gained new insights into our programs targeting basic field skills, Society. As you know from reading the exploration and mining technical Newsletter, our Society is strong and methods, ore deposits and metalloghealthy, with an increasingly global eny, and management. The curriculum reach. This provides an exceptional base is now well advertised with a current on which to build, thanks to the visionyear summary program posted in the ary steps taken by my predecessors, the Newsletter (see p. 50–51) and a regularly volunteers who support our Society, and updated course brochure posted on the dedicated staff at our Littleton headthe SEG website. These initiatives will quarters, which does wonders under assist members in planning attendance the wise guidance of Brian Hoal, our to selected courses. To optimize the Executive Director. I am therefore very impact of the program, the Commitenthusiastic about my new role as Prestee is formalizing a core portfolio of ident and deeply committed to serve all courses and field trips to be offered on of you to the best of my abilities. a semi-regular basis, and a selection of A major objective of SEG is to offer targeted meetings has been identified professional development and training to help prioritize where these courses opportunities to its members through and field trips will be delivered. In high quality publications, conferences, order to ensure relevance of the prolecturers, and a range of field trips, gram to SEG members, an informal courses, and workshops. These activities network of industry representatives are strongly supported by the SEG Founhas been established for feedback on dation (SEGF), the SEG Canada Foundaimportant questions. Responses to an tion (SEGCF) and various fund-raising informal questionnaire distributed initiatives. Our membership stands at to attendees at the Keystone meeting around 7,000, representranked field-based …we cannot ignore the current ing over 100 countries, courses above short with ~60% from industry downturn in commodity prices and courses and above and 40% from governits negative impact on the minerals workshops, conment and universities, firming that the industry, with consequent layoffs the latter including ~20% current program is of geoscience professionals and students. SEG, SEGF, and adequately balanced. challenging outlooks for students. SEGCF recognize the Please pass on any particular importance of suggestions to Elizastudents to the future of our profession, beth Holley, our program coordinator, through 80 active SEG Student Chapters at [email protected]. around the world, grants and fellowThe other area of focus is consoliships, and by supporting student attendation of the current global reaches of dance to SEG conferences. the Society and a measured expansion The past year was a busy and very in underrepresented regions such as productive time for SEG, with a successAsia and Africa, especially in important ful Keystone conference in September, industry hubs such as West Africa. The contributions to several other conferSEG is progressing well on this path: ences globally, one Special Publicathe next two SEG conferences will be tion, several field trip guidebooks, two held in Hobart, Tasmania, in 2015, and Compilation DVDs, as well as 13 short Izmir, Turkey, in 2016. Short courses courses, 4 workshops, and 12 field trips. and workshops have also recently been In addition, over $400,000 in Student offered or are planned in Brazil, China, Research Grants and Graduate Fellowand Namibia/South Africa. Efforts are ships were awarded to 97 students by underway to enhance our presence the SEG Foundations. in selected new areas; this requires a In my vision statement as a candistrategic and focused approach involvdate for SEG Officer, I proposed to focus ing close coordination within SEG efforts in the next few years on consoland industry support in order to offer idating and reinforcing existing initiaappealing services/publications and to tives so that we can continue to deliver overcome some of the logistical and strong programs to our members. This banking/payment issues that are combecomes particularly important in the mon in the developing world. context of the serious downturn curFinally, we cannot ignore the current rently faced by the mineral industry. downturn in commodity prices and On the Education and Training its negative impact on the minerals front, much progress has been made industry, with consequent layoffs of

geoscience professionals and challenging outlooks for students. This situation also impacts SEG through a decrease François Robert in corporate conSEG President 2015 tributions to the SEGF and SEGCF, reduction in industry enrollment at selected short courses such as Practical Methods in Mineral Exploration and even a decline in membership. As Dan Wood pointed out in the April 2014 Newsletter (p. 20–21), our industry is cyclic and there is not much we can do about that. History teaches us that the situation will definitely turn around—but not when! So what can we do? For the SEG, this means engaging industry leaders closely to ensure that our programs remain aligned with professional needs and priorities. We need to remind corporations of the importance of developing their young geoscientists by sending them to relevant courses and field trips, and of the long-term value of contributing to SEGF or SEGCF for continued strong and direct support to students. Established professionals, recent graduates, and current students should consider the advice of Dan Wood (April Newsletter, p. 20–21) and Andy Swarthout (July Newsletter, p. 8) and turn this challenge into an opportunity—the opportunity to become as employable as possible. Consider using this time to broaden your skills to other deposit types, mineral economics, geometallurgy, or languages, by attending short courses or field trips, and simply by reading technical material. Explorationists who have the opportunity should consider minebased employment as a way of better understanding what it takes to convert mineralization into ore. At a recent Mining Innovation Forum in Toronto, guest speaker Pierre Lassonde, a famous Canadian mining investor and founder of Franco-Nevada, made a strong case for an eventual upturn in commodity prices, driven in part by growing population and middle-class in developing areas such as Asia. The message for all of us should be to invest time and effort now to be fully prepared when the situation turns around. Now is when networking becomes very important, and this is a clear benefit of SEG membership. 1



No 100 • JANUARY 2015

S E G N E W S L E T T E R 9

       F O U N D AT I O N P R E S I D E N T I A L P E R S P E C T I V E

Threads of Continuity — Keeping the Fabric of Our Profession Strong A pleasant sense of nostalgia has set upon me as I contemplate the honor of stepping into the role of President of the SEG Foundation. To have the chance to give back to the preeminent professional society for my chosen career is a special opportunity, and I look forward to working with a great group of peers to further strengthen an already outstanding SEG and SEG Foundation. The fact that I am following in the footsteps of Andy Swarthout has caused me to reflect on the importance of continuity in the mineral exploration industry. Andy was one of the first and best bosses I have had in a career that now spans more decades than either of us will probably admit to. I started at Bear Creek Mining at a time when young geologists were often recruited out of universities for summer positions and teamed in the field with more seasoned explorationists to learn the trade. This mentoring relationship was fundamental in creating a strong professional culture within the company, and it was common to hear people talk about being a lifetime “Bear Creeker” or having come up through the “Anaconda School of Exploration.” I even recall senior geologists who had spent their entire careers with one company and passed on their experience and knowledge to dozens of geologists who had followed in their footsteps. Exploration companies had a fundamental role in the development of their employees. Furthermore, many economic geology professors had strong links to industry and became lifetime mentors for their students. However, over the last few decades, our industry has changed; continuity of employment is no longer common and economic geology programs at many universities no longer exist or have become increasingly focused on academic study. Andy and I have each worked for several other companies over the years, but I have always been able to look to him for advice and guidance. I know that he and others will continue to provide support as we guide the SEG

Foundation through the challenging times faced by our industry. The importance of mentors and mentoring relationships cannot be overemphasized in our industry, but, as noted above, they are increasingly difficult to establish and maintain due to less employment stability and the paucity of mid-career geoscientists—the missing generation that has been noted by many of my predecessors. Career development has become an increasing challenge for many young explorationists. However, as the role that companies and universities play in career development for mineral exploration geologists has decreased, I have been very pleased to note that the SEG has substantially increased support, particularly for our student members. This support comes in the form of student grants, field courses, visiting lecturers, workshops, student chapter support, conferences, and more—all of which provide opportunities to establish professional contacts and develop mentoring relationships. These activities are critical to the continuity of our profession. The principal role of the SEG Foundation is to raise funds to continue to support these activities. After several years of double-digit percentage growth, particularly in the number of student members, the SEG membership now appears to be stabilizing. The amount of support provided by the SEG Foundation and the SEG Canada Foundation to student members and SEG programs has also increased during this time to more than US$500,000 per year. However, as we face a sustained downturn in mineral exploration funding and activity, it has been increasingly challenging to provide this level of support, even though this is the time when it is most critical. Traditional multi-year support from mining companies has dropped off notably as budgets are further trimmed, but we have been fortunate to report a strong increase in individual donations to the SEGF over the past few years. It is truly encouraging to see this support for our society, which is indicative of our commitment

to giving back to our profession. Don Birak, past SEGF President, has Jack Black recently accepted SEG Foundation the challenge to President 2015 lead the SEGF Fund Raising Committee and will work closely with Gerry Carlson and his team at the SEG Canada Foundation as well as Nikki Jamison of SEG Littleton headquarters to seek creative ways to obtain funding to maintain the level of support we have been fortunate to provide for the past several years. I look forward to a challenging but rewarding year as the SEGF continues to seek ways to support our professional society. With an excellent group of Trustees and strong support from Brian Hoal and Christine Horrigan at SEG Littleton headquarters, I am confident we will rise to the challenge. Although the principal objective of the SEGF is to provide funding for educational activities that benefit members, particularly students, I believe that our role extends well beyond this. As ambassadors for our profession, we need to lay the groundwork for future generations. To this end, I would like to strongly encourage all members of SEG to seek opportunities to give back to our profession by making individual or corporate donations to the SEGF or by making time to participate in the many SEG activities that benefit other members and share your exploration experience. Your participation, in any form, will serve to provide threads of continuity that will strengthen the rich fabric of our profession. 1

SEG NEWSLETTER

10

No 100 • JANUARY 2015

Contributions 8/1/2014–10/31/2014

Thank you for your generous contributions to the Society and the SEG Foundation. SEG General Fund $250 –$500 Hodkiewicz, Paul, Australia McIntosh, Stephen, Australia McLemore, Virginia, USA

$100–$150 Almasan, Radu, Chile Barnes, Hubert, USA Boyes, Matthew, United Kingdom Bundtzen, Thomas, USA Fournier, Robert, USA Henry, Christopher, USA Hitzman, Murray, USA Klipfel, Paul, USA Large, Duncan, Germany Mauk, Jeffrey, USA McCurdy, Karr, USA Rodriguez Pevida, Luis, Spain Swarthout, Andrew, USA

Up to $99 Albinson, Tawn, Mexico Amazon Smile, USA Asare, Anthony, Ghana Backus, Rachel, Australia Barnard, Fred, USA Beleque, Andreia, Brazil Benson, Robert, USA Bernabe Evans, Pablo, Chile Bettles, Keith, USA Bookstrom, Arthur, USA Brosius, Eric, USA Carnier, Alexandre, Brazil Carrasco, Pablo, Chile Chitalin, Andrey, Russia Clifford, John, Ireland Danderfer, Andre, Brazil Davis, Nicholas, USA Della Libera, Michele, Italy Dilles, John, USA Drake-Brockman, Joseph, Australia El-Raghy, Sami, Australia Foster, Robert, United Kingdom Garay, Enrique, Peru Gialli, Stefano, Italy Hanneman, Harold, USA Haskins, Roger, USA Hoal, Brian, USA James, Ronald, Australia Johnson, David, USA Kay, Suzanne, USA Kekana, Sello, South Africa Kershaw, Byard, USA Klau, Wolfgang, Germany Krewedl, Dieter, USA Lecumberri Sanchez, Pilar, Switzerland Logsdon, Mark, USA McEwan, Craig, Australia Meldrum, Simon, Peru

More, Syver, USA Motta, Joao, Brazil Moye, Robert, Australia Mudrey, Michael, USA Nakashima, Kazuo, Japan Ogata, Takeyuki, Japan Painter, Matthew, Australia Petla, Sivarama Prasad, Swaziland Ramos, Frank, USA Reed, Mark, USA Rezende, Nelio, Brazil Shimizu, Toru, Japan Silva, Pedro, Chile Taksavasu, Taksorn, Thailand van Maastrigt, Peter, Netherlands Woodman, John, USA

SEG Foundation General Fund $5,000 Parratt, Ronald, USA

$250–$500 Hodkiewicz, Paul, Australia Lenters, Martin, Canada Steininger, Roger, USA

$100–$150 Carraher, Ruth, USA Flawn, Peter, USA Gardiner, Fraser, Bulgaria Graybeal, Frederick, USA Hitzman, Murray, USA Jennings, Donald, USA Large, Duncan, Germany Marlowe, Karl, USA Mathewson, David, USA Megaw, Peter, USA Myers, Russell, USA Parry, John, USA Price, Jonathan, USA

Up to $99 Barnard, Fred, USA Beukes, Nicolas, South Africa Channer, Dominic, Ecuador Della Libera, Michele, Italy Foster, Robert, United Kingdom Hoal, Brian, USA Krewedl, Dieter, USA Li, Xiaofeng, China Lienhard, Walter, USA Logsdon, Mark, USA More, Syver, USA Moye, Robert, Australia Taksavasu, Taksorn, Thailand

The Discovery Fund $100–$150 Schutz, J. Leroy, USA Thomsen, Michael, USA

Up to $99 Hasson, Sean, Bulgaria Whiteford, Sean, USA Woodman, John, USA

Hickok-Radford Fund $100 Bundtzen, Thomas, USA Millholland, Madelyn, USA Myers, Russell, USA Proffett, John, USA Puchner, Christopher, USA

Up to $99 Bernstein, Stefan, Denmark Cox, Bruce, USA Freeman, Curtis, USA Leonard, Kevin, USA Leveille, Richard, USA Turner, Thomas, USA

Hugo Dummett Fund $250–$500 Broughton, David, Canada Drobeck, Peter, USA Kirwin, Douglas, Thailand

$100–$200 Brown, H. Gassaway, USA Cocker, Mark, USA Mathewson, David, USA Maynard, James, USA Price, Jonathan, USA

Up to $99 Bolton, Barrie, Australia Cappa, James, USA Jarvis, William, USA Krewedl, Dieter, USA Logsdon, Mark, USA McLean, Neil, Australia More, Syver, USA Parker, Harry, USA Price, Barry, Canada Schafer, Robert, USA Wilde, Andy, Australia Wilton, Dean, USA

McKinstry Fund $100–$250 Brimhall, George, USA Broughton, David, Canada

Coveney, Raymond, USA Gustafson, Lewis, USA Hamm, Jack, USA Jenkin, Gawen, United Kingdom Jones, Richard, USA

Up to $99 Chapman, John, Canada Glass, Frank, Canada MacIntyre, Timothy, USA McConachy, Timothy, Australia More, Syver, USA Ogata, Takeyuki, Japan Oyarzun, Jorge, Chile Taguchi, Sachihiro, Japan

The Timothy Nutt Memorial Fund $100 Chadwick, Peter, Canada Foster, Robert, United Kingdom Speers, Roger, Burkina Faso

Up to $99 Barnard, Fred, USA Oberthuer, Thomas, Germany Schafer, Robert, USA

Student Field Trip Fund $45,000 Anonymous, USA

$1,000 Kirwin, Douglas, Thailand Seavoy, Ronald, USA

$300–$500 Broughton, David, Canada Groves, David, USA

$100–$250 Backer, Harold, USA Blakestad, Robert, USA Brown, H. Gassaway, USA Buhov, Valentin, Bulgaria Burstow, William, USA Duncan, David, Canada Foster, Robert, United Kingdom Henry, Christopher, USA Hudak, George, USA Janecky, David, USA Joensen, Svend, Denmark Longo, Anthony, USA MacTavish, Allan, Canada Mathewson, David, USA McCusker, Robert, USA Nettle, John, Australia Nordin, Gary, Canada Powell, Jon, USA Puentes, Cristian, USA



S E G N E W S L E T T E R 11

No 100 • JANUARY 2015

Contributions 8/1/2014–10/31/2014

Thank you for your generous contributions to the Society and the SEG Foundation. Schloderer, John, USA Smith, Patrick, USA Steinberger, Ingo, Germany

Up to $99 Ashley, Paul, Australia Azadbakht, Zeinab, Canada Barnard, Fred, USA Beckley, Richard, Australia Bettles, Keith, USA Bjerg, Ernesto, Argentina Brown, Rick, Brazil Burgoa Videla, Claudio, Chile Burisch, Mathias, Germany Chitalin, Andrey, Russia Clifford, John, Ireland Cortes, Marcelo, Chile Davis, James, USA Doucet, Dominique, Canada Dykeman, Candace, USA Herbort, Thomas, Switzerland Jones, Philip, Australia Klipfel, Paul, USA Lebert, Breagh, Canada Li, Jian-Wei, China McEwan, Craig, Australia Myers, Russell, USA Ndalulilwa, Kaarina, Namibia Parker, Harry, USA Polozov, Alexander, Russia Simpson, Thomas, USA Stanton-Cook, Kim, Australia Sulfrian, Charles, USA

Underwood, David, South Africa Wilton, Dean, USA Yonemura, Kazuhiro, Japan

The Alberto Terrones L. Fund Up to $99 Barnard, Fred, USA Martinez, Manuel, Chile Sanchez Mora, Dennis, Costa Rica

Student Fellowship Fund Corporate Contributions $50, 000 Anglo American plc, United Kingdom

$30,000 Barrick Gold Corporation, Canada

$45,000 Anonymous, USA

$1,000 Seavoy, Ronald, USA

$500 Drobeck, Peter, USA

$100–$200 Hitzman, Murray, USA Kotlyar, Boris, USA Powell, Jon, USA Smith, Patrick, USA Xu, Jiuhua, China

Up to $99 Beckley, Richard, Australia Boullier, Anne-Marie, France Chitalin, Andrey, Russia Lebert, Breagh, Canada Polozov, Alexander, Russia Simpson, Thomas, USA

Canada Foundation $1,000

Debicki, Edward, Canada Dion, Claude, Canada Fitzpatrick, Arthur, Canada Galley, Alan, Canada Hannington, Mark, Canada Hart, Thomas, Canada Idziszek, Chet, Canada Liverton, Timothy, Canada Malfair, Mark, Canada Pawliuk, David, Canada Pearson, William, Canada Perreault, Serge, Canada Richards, Jeremy, Canada Tosdal, Richard, USA Walton, Ian, Canada Zajac, I., Canada Zentilli, Marcos, Canada

Franklin, James, Canada

$250–$500 Brisbin, Daniel, Canada Hattori, Keiko, Canada Hodder, Robert, Canada Linnen, Robert, Canada MacTavish, Allan, Canada Reeve, Edward, Canada Robert, François, Canada

$100–$200 Armstrong, Brett, Canada Boyd, Robert, Canada Cashin, Peter, Canada Cote-Mantha, Olivier, Canada

Up to $99 Barnard, Fred, USA Carmichael, Bob, Canada Channer, Dominic, Ecuador Della Libera, Michele, Italy Doucet, Dominique, Canada Gagnier, Claude, Canada Grace, Kenneth, Canada Hollings, Peter, Canada Price, Barry, Canada Rampton, Vernon, Canada Razique, Abdul, Canada Schafer, Robert, USA Thompson, Ian, Canada Whiteford, Sean, USA

IOCG Deposits: The Cloncurry Experience Deposit Understanding – Exploration Case Studies – Field Trip 4th – 6th March 2015 Cloncurry, NW Queensland, Australia Presented by The Economic Geology Research Centre (EGRU), James Cook University and NW QLD mining companies Deposits to be discussed and/or visited include Ernest Henry, the E1 Group, Monakoff, Osborne, Mt Eliot/SWAN, Starra, The Great Australian, Little Eva and Lorena Further Information and registration: www.jcu.edu.au/egru PAID ADVERTISEMENT

SEG NEWSLETTER

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. . . from page 1

No 100 • JANUARY 2015

Footprints: Hydrothermal Alteration and Geochemical Dispersion Around Porphyry Copper Deposits (continued)

up to 7 km laterally (Butte, Christmas, Highland Valley) from the porphyry ore center. To understand the metal dispersion outside the ore zone, we focused on the D-type veins with alteration selvages containing sericite, pyrite, and chlorite, the latter being common in hydrolytic assemblages where rocks are dominantly of intermediate to mafic compositions. These veins extend varying distances vertically and laterally from the ore zone. The distribution of SWIR recognized minerals and changes in rock compositions of just two of the many elements (Tl, Bi) that were mapped vertically and laterally in the Ann Mason porphyry Cu-Mo deposit in Yerington and are shown in Figure 2 as examples. Petrography, electron microprobe analysis,

zone with Cu ± Mo/Au that is enclosed in zones enriched in Zn, Pb, and Ag and, in some cases, Mn (Meyer et al., 1968). Gold-Ag may be present laterally away from (e.g., Lang and Eastoe, 1988) or above (Hedenquist et al., 1998) the porphyry Cu core. Exploration programs for porphyry Cu deposits rely on many techniques, but from a geologist’s perspective, whole-rock lithogeochemistry and short-wave infrared (SWIR) spectrometry have become standard tools in addition to the hammer and hand lens. To assist this effort, we established the vertical and lateral footprint of a porphyry Cu deposit using SWIR and lithogeochemistry (Fig. 1). We tracked alteration paths ~1 to 5 km vertically (e.g., Yerington, Red Chris, Galore Creek) or

and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) of the hydrolytic mineral alteration assemblages analyzed in the lithogeochemical and SWIR data sets further constrain the interpretation of the resulting patterns (Alva-Jimenez, 2011; Cohen, 2011).

METHODOLOGY Rocks were chosen as the sample medium in order to ascertain the primary elemental and mineralogic dispersion halos. However, in many environments during initial exploration, soil may be nearly as effective as rocks, as soils capture a geographic average that may include both weakly and strongly altered rocks. c.) Lateral distribution of elements

b.) Vertical distribution of elements

Above Mineralized Zone

ADVANCED ADV AD A DVANCE DV NCED CE CED ED D ARGILLIC AR A RGILLIC RG C +Tl > 1.5 ppm +Li > 15 ppm

PROPYLITIC

SERICITIC SE S PHYLLIC PH H

+Sb > 4 ppm; As > 50 ppm +Bi > 1 ppm

rother hyd

Mo > 5 ppm

mal

Return to background or slightly elevated Zn, Mn, Pb, Sr, Co, Ni, Li, ± As, Sb

Flow path of magmatic-derived fluid Flow path of external fluid

tion altera

Depleted

+Cu >0.1 wt%

Return to background or slightly elevated Zn, Mn, Pb, Sr, Co, Ni, Li, ± As, Sb

-Zn, Mn,Co, Ni, Sr, Pb, As, Tl, Cs, Rb, Li

POTASSIC

+ Na, Ca, Sr -Fe, K, Cu , Zn, Mn, Co, Ni,

SODICCALCIC

+ Na, Ca, Sr -Fe, K, Cu , Zn, Mn, Co, Ni, As, Sb

granite porphyry dikes

maag magmatic m gm mati ma ticc fluids fluiid id ds

Polymetallic veins ADVANCED ARGILLIC

1 km

Bi-Se-Te±Mo

SERICITIC

Top of Mineralized Zone

+Sn > 4 ppm +W > 5 ppm

atic

Added

PROPYLITIC

+Se > 4 ppm

m mag

Explanation

INTERMEDIATE ARGILLIC

+Te > 1 ppm

of zone

+ -

te spec. hema t i

Tl, As, Sb, Li ±Bi

LATE LA LA AT TE INTERMEDIATE IIN NTE NT ER ER RM MED ED DIIA AT A T TE E ARGILLIC AR AR RG GILL LIC

Increasing Tl, As, Bi, Se, Te

Li, Zn, V, ± As, Sb elevated compared to core

1 km

SERICITIC Mo +Bi-Se-Te

PROPYLITIC

Elevation of Highest Grade Cu Localized Tl, As, Bi

Depletion in As, Mn, Pb, Zn, Cs, Sb, Tl in K silicate core

1 km

POTASSIC

Mo±Bi, Se, Te

Outer Zn, Pb, Mn elevated compared to core

Deep Environment

1 km

FIGURE 1. (Cont.) b.) Vertical variations in trace elements in a porphyry Cu system. c.) Schematic changes in hydrothermal alteration assemblages and trace elements through a porphyry Cu system viewed as a series of map views through a vertical system.

SODICCALCIC

Mo±Bi, Se, Te halo

Na, Ca, and Sr enrichment, K, Fe, Mn, V, Pb, Zn, Cs, Cu depletion

S E G N E W S L E T T E R 13

a.

100% Biot

ill eH Blu t l u fa

119°15’W

100%

100% Biot

ill eH Blu lt fau

Ann Mason PCD

offset part of Ann Mason PCD beneath Blue Hill fault

b.

39°00’N

39°00’N

Sing atse fault

119°15’W

Sing atse fault

No 100 • JANUARY 2015

km

2

km

0

2

Albite-Ser±Chl-Py

Sericite±Tourm-Py Ser-Chl±Felds-Hem (weak Ser)

Albite-Chl-Epid±Ksp

Chl-Epid+Felds-Hem (Propylitic)

Na-Ca (Plag-Act) Endoskarn (Plag-Cpx)

K-silicate: Biotite (weak, 2.5 ppm

fault atse

fault atse Sing

ill eH Blu t l u fa

d.

39°00’N

Tl concentration < 0.8 ppm 0.8 - 2.5 ppm > 2.5 ppm

Dominant Hydroxl-bearing Mineral

(symbols reflect dominant or local presence of sericitic mineral) Fresh rocks Na-Ca or propylitic Sericitic hornblende actinolite sericite (mus or ill.) chlorite tourmaline SWIR 2200nM peak epidote 2210 to 2230 pyrophyllite

ill eH Blu t l u fa

Ann Mason PCD

Ann Mason PCD

offset part of Ann Mason PCD beneath Blue Hill fault

offset part of Ann Mason PCD beneath Blue Hill fault

N

Jurass

ic up

km

Sing

100% 0% >5 0% 10

Advanc Arg (Qz-Pyrop-Alun-Topaz)

c.

0

Biot

p

Hydrothermal Alteration Zones

N

100%

N Jurassic u

p

0

Ann Mason PCD

offset part of Ann Mason PCD beneath Blue Hill fault

Biot

N Jurassic u

39°00’N



0

2

Jurass

ic up

km

2

Alteration Assemblages Pyrophyllite-alunite-topaz Sericitic

Sericite-albite Albite-sericite

Sodic-calcic Albite

K-silicate - ore zone Fresh rock

FIGURE 2. a.) Map of hydrothermal alteration assemblages in the region of the Ann Mason porphyry Cu-Mo deposit from Dilles and Einaudi (1992) and from J.H. Dilles (unpub. mapping, 2014) superposed on the geology from Proffett and Dilles (1984). Pale purple units are postmineral Tertiary volcanic rocks. All Jurassic rocks are outlined, but the different units are not shown to avoid a cluttered map. b.) Map of hydrothermal alteration with distribution of hydrous alteration minerals identified and 2,200-nm peak using SWIR instrument. Identified hydrous mineralogy is plotted according to the dominant mineral in color and the mineral phase in the rocks. Geochemical maps of c.) Tl and d.) Bi for rocks from Yerington, Nevada. Symbols are color coded to page 14 . . . to hydrothermal alteration assemblages mapped in the field and inverted from standard geochemical plots.

SEG NEWSLETTER

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. . . from page 13

Footprints: Hydrothermal Alteration and Geochemical Dispersion Around Porphyry Copper Deposits (continued)

Lithogeochemical analyses Commercial laboratories provide rapid turnaround of chemical analyses including sample preparation, internal standardization, and replicates. In this study, we used ALS Global for 48 elements (ME-MS61 method) that include all major elements but silica, which is lost as SiF4 gas. The best sample dissolution combined with low detection limit is achieved when rock is digested by a mixture of four acids (hydrofluoric-nitric-perchloric-hydrochloric). This dissolution method liberates nearly 100% of all elements except for Zr, Hf, and a small percentage of heavy rare earth elements (REE) and Y contained in refractory zircon. Coupled with the ICP-MS + ICP-atomic emission spectroscopy (AES) instrumental finish, the resulting assays report elements at detection limits similar to crustal abundance. At a minimum, assay values an order of magnitude or more greater than average crustal abundances in rocks (Table 1) should be viewed as anomalous and attract further attention from an exploration program. Alternative sample digestion procedures are available but, compared to four-acid digestions, are more costly, lead to incomplete dissolutions, or have higher detection limits. Aqua regia dissolves sulfides and oxides effectively,

but cannot dissolve silicate phases where many useful pathfinder elements reside and, furthermore, that commonly survive weathering of rocks to form soil. Lithium metaborate flux results in complete dissolution of rocks so that total silica, Zr, and Hf concentrations are obtained, but this fusion technique is expensive, increases the sample blank, and produces higher detection limits for trace elements.

SWIR analyses Short-wave infrared spectra were collected from rock chips from larger samples analyzed for lithogeochemistry. As the SWIR spectrum is collected from a small rock surface (~0.5-cm diameter), the sample volume is much smaller than the corresponding one for lithogeochemistry. Samples were broken in the field such that the effect of surface weathering is minimized. The hydrous minerals that are the most widespread in sericitic alteration are white micas/clays (muscovite/illite commonly called “sericite”) and chlorite. Each has distinctive spectra that also yield compositional information (Thompson et al., 1999). SWIR instruments efficiently analyze 500 to 1,000 samples per day in the laboratory, or in the field from samples archived in chip trays.

TABLE 1. Typical Pathfinder Elemental Ranges (ppm) Metal

Average crust abundance1

Cu Mo Sn W Mn Zn Pb Ag Ni Co Se Te Bi As Sb Li Tl Hg Cs

No 100 • JANUARY 2015

Potassic

Deep sericitic

Shallow sericitic

75 >200–ore 100 50 1 0.5–ore 2–20 0.5–5 2.5 0.5–10 2–30 bkgd 1 bkgd 2–20 0.5–5 1,400