Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
August 2011 Volume 7, Number 4 ISSN 1811-5209 When the Continental Crust Melts EDWARD W. SAWYER, BERNARDO CESARE, and MICHAEL BROWN, Guest Editors How the Crust Gets Really Hot Melting Experiments and Thermodynamic Calculations Interpreting Microstructures Crustal Melting and the Flow of Mountains Melt Flow through the Crust www.elementsmagazine.org www.elements. geoscienceworld.org When the Continental Crust Melts Guest Editors: Edward W. Sawyer, Bernardo Cesare, and Michael Brown 229 235 When the Continental Crust Melts Edward W. Sawyer, Bernardo Cesare, and Michael Brown How Does the Continental Crust Get Really Hot? ABOUT THE COVER: Spider Wall on the south face of Nuptse (the summit ridge is at ~7650 m, and the wall is ~1700 m in height), showing a network of leucogranite dykes in metasedimentary rocks of the Everest Series (centre) above the Nuptse leucogranite, visible at the bottom left and right. Leucogranites emplaced in the shallow crust are the end product of melting of the deep crust in orogenic belts. The view is from Pokalde Peak in the Khumbu Himalaya, Nepal. IMAGE COURTESY OF MICAH JESSUP, UNIVERSITY OF TENNESSEE, USA p q 241 grt opx kfs pl liq grt opx crd kfs pl liq op xp l li q pl liq gr t liq grt bt pl liq kfs pl liq Chris Clark, Ian C. W. Fitzsimons, David Healy, and Simon L. Harley grt opx bt Elements is published six times a year. Individuals are encouraged to join any one of the participating societies to receive Elements. Institutional subscribers to any of the following journals —American Mineralogist, Clay Minerals, Clays and Clay Minerals, Mineralogical Magazine, and The Canadian Mineralogist—also receive one copy of Elements as part of their 2011 subscription. Institutional subscriptions are available for US$160 (US$175 non-US addresses) a year in 2011. Contact the managing editor (tremblpi@ ete.inrs.ca) for information. Copyright 2011 by the Mineralogical Society of America All rights reserved. Reproduction in any form, including translation to other languages, or by any means—graphic, electronic or mechanical, including photocopying or information storage and retrieval systems—without written permission from the copyright holder is strictly prohibited. Publications mail agreement no. 40037944 Printed in USA ISSN 1811-5209 (print) ISSN 1811-5217 (online) Volume 7, Number 4 • August 2011 grt bt kfs pl Elements is published jointly by the Mineralogical Society of America, the Mineralogical Society of Great Britain and Ireland, the Mineralogical Association of Canada, the Geochemical Society, The Clay Minerals Society, the European Association of Geochemistry, the International Association of GeoChemistry, the Société Française de Minéralogie et de Cristallographie, the Association of Applied Geochemists, the Deutsche Mineralogische Gesellschaft, the Società Italiana di Mineralogia e Petrologia, the International Association of Geoanalysts, the Polskie Towarzystwo Mineralogiczne (Mineralogical Society of Poland), the Sociedad Española de Mineralogía, the Swiss Society of Mineralogy and Petrology, and the Meteoritical Society. It is provided as a benefit to members of these societies. opx pl liq 247 Is the Crucible Reproducible? Reconciling Melting Experiments with Thermodynamic Calculations Richard W. White, Gary Stevens, and Timothy E. Johnson Melted Rocks under the Microscope: Microstructures and Their Interpretation Marian B. Holness, Bernardo Cesare, and Edward W. Sawyer 253 Crustal Melting and the Flow of Mountains 261 Organizing Melt Flow through the Crust Rebecca A. Jamieson, Martyn J. Unsworth, Nigel B. W. Harris, Claudio L. Rosenberg, and Karel Schulmann Michael Brown, Fawna J. Korhonen, and Christine S. Siddoway D E PA R T M E N T S Editorial – Is Science a Contact Sport? . . . . . . . . . . . . . . . . 219 From the Editors – John Valley, Principal Editor 2012–2014. . 220 The Elements Toolkit – Smashing Up Stones . . . . . . . . . . . 221 People in the News – Williams-Jones, Ferry, Stolper. . . . . . . 222 Meet the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 Society News Swiss Society of Mineralogy and Petrology . . . . . . . . . . . . . . 267 Association of Applied Geochemists . . . . . . . . . . . . . . . . . . .268 Mineralogical Society of Great Britain and Ireland . . . . . . . 269 International Association of GeoChemistry . . . . . . . . . . . . . .270 European Association of Geochemistry . . . . . . . . . . . . . . . .271 The Clay Minerals Society . . . . . . . . . . . . . . . . . . . . . . . . . . .272 The Meteoritical Society . . . . . . . . . . . . . . . . . . . . . . . . . . . .273 Mineralogical Society of America . . . . . . . . . . . . . . . . . . . . 274 International Association of Geoanalysts . . . . . . . . . . . . . . . . 276 Société Française de Minéralogie et de Cristallographie . . .277 Geochemical Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .278 Mineralogical Association of Canada . . . . . . . . . . . . . . . . . 280 Book Review – Timescales of Magmatic Processes . . . . . . . . . . 282 Meeting Report – Making Science Matter . . . . . . . . . . . . . 284 Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 Advertisers in This Issue . . . . . . . . . . . . . . . . . . . . . . . . . 286 Parting Shots – Standing Stones . . . . . . . . . . . . . . . . . . . . 288 217 PARTICIPATING SOCIETIES The Mineralogical Society of America is composed of individuals interested in mineralogy, crystallography, petrology, and geochemistry. Founded in 1919, the Society promotes, through education and research, the understanding and application of mineralogy by industry, universities, government, and the public. Membership benefits include special subscription rates for American Mineralogist as well as other journals, a 25% discount on Reviews in Mineralogy & Geochemistry series and Monographs, Elements, reduced registration fees for MSA meetings and short courses, and participation in a society that supports the many facets of mineralogy. SOCIETY NEWS EDITOR: Andrea Koziol ([email protected]) Mineralogical Society of America 3635 Concorde Pkwy Ste 500 Chantilly, VA 20151-1110, USA Tel.: 703-652-9950; fax: 703-652-9951 [email protected] www.minsocam.org The Mineralogical Society of Great Britain and Ireland is an international society for all those working in the mineral sciences. The Society aims to advance the knowledge of the science of mineralogy and its application to other subjects, including crystallography, geochemistry, petrology, environmental science and economic geology. The Society furthers its aims through scientific meetings and the publication of scientific journals, books and monographs. The Society publishes Mineralogical Magazine and Clay Minerals. Students receive the first year of membership free of charge. All members receive Elements. SOCIETY NEWS EDITOR: Kevin Murphy ([email protected]) The Mineralogical Society 12 Baylis Mews, Amyand Park Road Twickenham, Middlesex TW1 3HQ, UK Tel.: +44 (0)20 8891 6600 Fax: +44 (0)20 8891 6599 [email protected] www.minersoc.org The Association of Applied Geochemists is an international organization founded in 1970 that specializes in the field of applied geochemistry. It aims to advance the science of geochemistry as it relates to exploration and the environment, further the common interests of exploration geochemists, facilitate the acquisition and distribution of scientific knowledge, promote the exchange of information, and encourage research and development. AAG membership includes the AAG journal, Geochemistry: Exploration, Environment, Analysis; the AAG newsletter, EXPLORE; and Elements. The Geochemical Society (GS) is an international organization founded in 1955 for students and scientists involved in the practice, study and teaching of geochemistry. Our programs include co-hosting the annual Goldschmidt ConferenceTM, editorial oversight of Geochimica et Cosmochimica Acta (GCA), supporting geochemical symposia through our Meeting Assistance Program, and supporting student development through our Student Travel Grant Program. GS annually recognizes excellence in geochemistry through its medals, lectures and awards. Members receive a subscription to Elements, special member rates for GCA and G-cubed, and publication and conference discounts. SOCIETY NEWS EDITOR: Patrice de Caritat ([email protected]) Association of Applied Geochemists P.O. Box 26099 Nepean, ON K2H 9R0, Canada Tel.: 613-828-0199; fax: 613-828-9288 [email protected] www.appliedgeochemists.org SOCIETY NEWS EDITOR: Seth Davis ([email protected]) Geochemical Society Washington University Earth & Planetary Sciences One Brookings Drive, Campus Box #1169 St. Louis, MO 63130-4899, USA Tel.: 314-935-4131; fax: 314-935-4121 [email protected] Explore GS online at www.geochemsoc.org The European Association of Geochemistry was founded in 1985 to promote geochemical research and study in Europe. It is now recognized as the premiere geochemical organization in Europe encouraging interaction between geochemists and researchers in associated fields, and promoting research and teaching in the public and private sectors. SOCIETY NEWS EDITOR: Liane G. Benning ([email protected]) Membership information: www.eag.eu.com/membership The Mineralogical Association of Canada was incorporated in 1955 to promote and advance the knowledge of mineralogy and the related disciplines of crystallography, petrology, geochemistry, and economic geology. Any person engaged or interested in these fields may become a member of the Association. Membership benefits include a subscription to Elements, reduced cost for subscribing to The Canadian Mineralogist, a 20% discount on short course volumes and special publications, and a discount on the registration fee for annual meetings. SOCIETY NEWS EDITOR: Pierrette Tremblay ([email protected]) The International Association of GeoChemistry (IAGC) has been a pre-eminent international geochemical organization for over 40 years. Its principal objectives are to foster cooperation in the advancement of applied geochemistry by sponsoring specialist scientific symposia and the activities organized by its working groups and by supporting its journal, Applied Geochemistry. The administration and activities of IAGC are conducted by its Council, comprising an Executive and ten ordinary members. Day-to-day administration is performed through the IAGC business office. SOCIETY NEWS EDITOR: Chris Gardner ([email protected]) IAGC Business Office 275 Mendenhall Laboratory 125 South Oval Mall Columbus, OH 43210, USA Tel.: 614-688-7400; fax: 614-292-7688 www.iagc-society.org Mineralogical Association of Canada 490, de la Couronne Québec, QC G1K 9A9, Canada Tel.: 418-653-0333; fax: 418-653-0777 [email protected] www.mineralogicalassociation.ca The Clay Minerals Society (CMS) began as the Clay Minerals Committee of the US National Academy of Sciences – National Research Council in 1952. In 1962, the CMS was incorporated with the primary purpose of stimulating research and disseminating information relating to all aspects of clay science and technology. The CMS holds an annual meeting, workshop, and field trips, and publishes Clays and Clay Minerals and the CMS Workshop Lectures series. Membership benefits include reduced registration fees to the annual meeting, discounts on the CMS Workshop Lectures, and Elements. SOCIETY NEWS EDITOR: Jeffery Greathouse ([email protected]) The Clay Minerals Society 3635 Concorde Pkwy Ste 500 Chantilly, VA 20151-1110, USA Tel.: 703-652-9960; fax: 703-652-9951 [email protected] www.clays.org The Société Française de Minéralogie et de Cristallographie, the French Mineralogy and Crystallography Society, was founded on March 21, 1878. The purpose of the Society is to promote mineralogy and crystallography. Membership benefits include the “bulletin de liaison” (in French), the European Journal of Mineralogy, Elements, and reduced registration fees for SFMC meetings. SOCIETY NEWS EDITOR: Anne-Line Auzende ([email protected]) SFMC Campus Boucicaut, Bâtiment 7 140 rue de Lourmel 75015 Paris, France www.sfmc-fr.org E LEMENTS The Deutsche Mineralogische Gesellschaft (German Mineralogical Society) was founded in 1908 to “promote mineralogy and all its subdisciplines in teaching and research as well as the personal relationships among all members.” Its great tradition is reflected in the list of honorary fellows, who include M. v. Laue, G. v. Tschermak, P. Eskola, C.W. Correns, P. Ramdohr, and H. Strunz. Today, the Society especially tries to support young researchers, e.g. to attend conferences and short courses. Membership benefits include the European Journal of Mineralogy, the DMG Forum, GMit, and Elements. SOCIETY NEWS EDITOR: Michael Burchard ([email protected]) Deutsche Mineralogische Gesellschaft [email protected] www.dmg-home.de The Società Italiana di Mineralogia e Petrologia (Italian Society of Mineralogy and Petrology), established in 1940, is the national body representing all researchers dealing with mineralogy, petrology, and related disciplines. Membership benefits include receiving the European Journal of Mineralogy, Plinius, and Elements, and a reduced registration fee for the annual meeting. SOCIETY NEWS EDITOR: Marco Pasero ([email protected]) Società Italiana di Mineralogia e Petrologia Dip. di Scienze della Terra Università di Pisa, Via S. Maria 53 I-56126 Pisa, Italy Tel.: +39 050 2215704 Fax: +39 050 2215830 [email protected] www.socminpet.it The International Association of Geoanalysts is a worldwide organization supporting the professional interests of those involved in the analysis of geological and environmental materials. Activities include the management of proficiency testing programmes for bulk rock and micro-analytical methods, the production and certification of reference materials and the publication of the Association’s journal, Geostandards and Geoanalytical Research. SOCIETY NEWS EDITOR: Michael Wiedenbeck ([email protected]) International Association of Geoanalysts Ms. Jennifer Cook, Hon. Sec. British Geological Survey Keyworth, Nottingham, NG12 5GC, UK http://geoanalyst.org The Polskie Towarzystwo Mineralogiczne (Mineralogical Society of Poland), founded in 1969, draws together professionals and amateurs interested in mineralogy, crystallography, petrology, geochemistry, and economic geology. The Society promotes links between mineralogical science and education and technology through annual conferences, field trips, invited lectures, and publishing. Membership benefits include subscriptions to Mineralogia and Elements. SOCIETY NEWS EDITOR: Zbigniew Sawłowicz ([email protected]) Mineralogical Society of Poland Al. Mickiewicza 30, 30-059 Kraków, Poland Tel./fax: +48 12 6334330 [email protected] www.ptmin.agh.edu.pl The Sociedad Española de Mineralogía (Spanish Mineralogical Society) was founded in 1975 to promote research in mineralogy, petrology, and geochemistry. The Society organizes annual conferences and furthers the training of young researchers via seminars and special publications. The SEM Bulletin published scientific papers from 1978 to 2003, the year the Society joined the European Journal of Mineralogy and launched Macla, a new journal containing scientific news, abstracts, and reviews. Membership benefits include receiving the European Journal of Mineralogy, Macla, and Elements. SOCIETY NEWS EDITOR: Juan Jimenez Millan ([email protected]) Sociedad Española de Mineralogía [email protected] www.ehu.es/sem The Swiss Society of Mineralogy and Petrology was founded in 1924 by professionals from academia and industry and by amateurs to promote knowledge in the fields of mineralogy, petrology and geochemistry and to disseminate it to the scientific and public communities. The Society coorganizes the annual Swiss Geoscience Meeting and publishes the Swiss Journal of Geosciences jointly with the national geological and paleontological societies. SOCIETY NEWS EDITOR: Urs Schaltegger ([email protected]) Swiss Society of Mineralogy and Petrology Université de Fribourg, Département des Géosciences Chemin du Musée 6, Pérolles 1700 Fribourg, Switzerland Tel. +41 26 300 89 36; fax: +41 26 300 97 65 http://ssmp.scnatweb.ch The Meteoritical Society is an international organization founded in 1933 for scientists, collectors, and educators to advance the study of meteorites and other extraterrestrial materials and their parent asteroids, comets, and planets. Members receive our journal, Meteoritics and Planetary Science, reduced rates for Geochimica et Cosmochimica Acta, which we cosponsor, the Meteoritical Bulletin, and Elements. We organize annual meetings, workshops, and field trips, and support young planetary scientists worldwide. Through our medals and awards, we recognize excellence in meteoritics and allied fields. SOCIETY NEWS EDITOR: Cari Corrigan ([email protected]) MEMBERSHIP INFORMATION: http://meteoriticalsociety.org Affi liated Societies The International Mineralogical Association, the European Mineralogical Union, and the International Association for the Study of Clays are affi liated societies of Elements. The affi liated status is reserved for those organizations that serve as an “umbrella” for other groups in the fields of mineralogy, geochemistry, and petrology, but that do not themselves have a membership base. 218 A UGUS T 2011 EDITORIAL IS SCIENCE A CONTACT SPORT? PRINCIPAL EDITORS HARRY Y. (Hap) McSWEEN, University of Tennessee, USA ([email protected]) JAMES I. DREVER, University of Wyoming, USA ([email protected]) GEORGES CALAS, IMPMC, France ([email protected]) ADVISORY BOARD 2011 JOHN BRODHOLT, University College London, UK NORBERT CLAUER, CNRS/UdS, Université de Strasbourg, France WILL P. GATES, SmecTech Research Consulting, Australia GEORGE E. HARLOW, American Museum of Natural History, USA JANUSZ JANECZEK, University of Silesia, Poland HANS KEPPLER, Bayerisches Geoinstitut, Germany DAVID R. LENTZ, University of New Brunswick, Canada ANHUAI LU, Peking University, China ROBERT W. LUTH, University of Alberta, Canada DAVID W. MOGK, Montana State University, USA TAKASHI MURAKAMI, University of Tokyo, Japan ROBERTA OBERTI, CNR Istituto di Geoscienze e Georisorse, Pavia, Italy TERRY PLANK, Lamont-Doherty Earth Observatory, USA XAVIER QUEROL, Spanish Research Council, Spain MAURO ROSI, University of Pisa, Italy BARBARA SHERWOOD LOLLAR, University of Toronto, Canada TORSTEN VENNEMANN, Université de Lausanne, Switzerland OLIVIER VIDAL, Université J. Fourier, France MEENAKSHI WADHWA, Arizona State University, USA BERNARD WOOD, University of Oxford, UK JON WOODHEAD, University of Melbourne, Australia EXECUTIVE COMMITTEE CARLOS AYORA IBÁÑEZ, Sociedad Española di Mineralogía LIANE G. BENNING, European Association of Geochemistry THOMAS D. BULLEN, International Association of GeoChemistry PETER C. BURNS, Mineralogical Association of Canada GIUSEPPE CRUCIANI, Società Italiana di Mineralogia e Petrologia BARBARA L. DUTROW, Mineralogical Society of America, Chair W. CRAWFORD ELLIOTT, The Clay Minerals Society MONICA M. GRADY, The Meteoritical Society BERNARD GROBÉTY, Swiss Society of Mineralogy and Petrology GUY LIBOUREL, Société Française de Minéralogie et de Cristallographie MAREK MICHALIK, Mineralogical Society of Poland EDWIN A. SCHAUBLE, Geochemical Society CLIFFORD R. STANLEY, Association of Applied Geochemists PETER TRELOAR, Mineralogical Society of Great Britain and Ireland FRIEDHELM VON BLANCKENBURG, Deutsche Mineralogische Gesellschaft MICHAEL WIEDENBECK, International Association of Geoanalysts MANAGING EDITOR PIERRETTE TREMBLAY, [email protected] EDITORIAL OFFICE 490, rue de la Couronne Québec (Québec) G1K 9A9, Canada Tel.: 418-654-2606 Fax: 418-653-0777 Layout: POULIOT GUAY GRAPHISTES Copy editor: THOMAS CLARK Proofreaders: THOMAS CLARK and DOLORES DURANT Printer: ALLEN PRESS The publishers assume no responsibility for any statement of fact or opinion expressed in the published material. The appearance of advertising in this magazine does not constitute endorsement or approval of the quality or value of the products or of claims made for them. www.elementsmagazine.org E LEMENTS new offerings, panel members who fairly decide which research proposals are most deserving of funding, members of advisory boards that thoughtfully set science priorities when everything can’t be supported. Our referees ensure that we play by the rules, which for science means that truth and accuracy should ultimately win. For the most part, being a referee is a difficult and thankless job, an uncompensated duty that we assume for the betterment of our shared scientific community. In science, virtually all of us, sooner or later, get to be referees. Few of us are actually trained for these responsibilities, though, and that is probably unfortunate. Those of us who teach need to share with our students the rules and techniques by which we referee, and instill in them an appreciation for the trust we place in referees and a sense of respect for its paramount importance to science. Hap McSween My university plays (American) football—these are big-time contests, held in a stadium that seats more than a hundred thousand spectators and televised more often than not. Watching a game not long ago, I was taken aback by the crowd’s vociferous reaction to a referee’s ruling against the home team. Based on an instant It is human nature to be loyal to the replay projected onto a gigantic The loyal crowd just home team, to our colleagues and screen at the top of the stadium, the ruling seemed fair to me. The wanted their team to friends, and even to our scientific referee was close to the action and win, and any rulings passions. Loyalty colors the way we respond to our pastimes, our poliobviously had some experience in by the guy in the tics, and our professions. It seems such matters. But the crowd around me, none of whom I assume actu- striped shirt that did to me that in the past few decades, ally had any experience refereeing, not further that cause various factions of society have learned to express their loyalty in was furious at the call and roared were roundly booed. some angry and less-than-producits displeasure. Later in the game, tive ways, such as rudely booing the a similar ruling against the opponent resulted in the crowd’s jubilation. I doubt opposing team and polarizing our political discusthat this was their vocal affirmation of excellence sions. I don’t sense that this societal hardening and accuracy in officiating. A good call was, by has spilled over into science yet. But we should definition, one that favored the home team. The guard against it. My hope, and my expectation, is loyal crowd just wanted their team to win, and that the community of scientists will continue to any rulings by the guy in the striped shirt that did conduct their sparring contests with respect, and not further that cause were roundly booed. This to value our referees and spare them the jeers that is American football, but the same fan behavior greet the guys in the zebra shirts on game day. (or worse) is a part of the other “football” played around the world. Hap McSween, University of Tennessee [email protected] We all understand this, of course. Sports are all about winning, for the players and for the spectators, and it is easy to get caught up in the game and lose track of the ideal of sportsmanship. The reason I bring this up is that science is sometimes described as a contact sport. In science, competing ideas often collide. We are obligated to champion our hypotheses, at least until they are proven wrong, and to marshal evidence against hypotheses with which we disagree. This is the way science works. Our contests are based on ideas rather than brawn, but sometimes they can get confrontational or even nasty. Science, too, thankfully has its referees: reviewers who provide insightful criticisms of manuscripts, editors who adjudicate when reviewers don’t agree, book reviewers who provide valuable insights into 219 Football referee signaling a touchdown. PHOTO YOBRO10 | DREAMSTIME.COM A UGUS T 2011 FROM THE EDITORS THIS ISSUE What started as a proposal on the traditional aspects of migmatites evolved into “When the Continental Crust Melts” after the proposers were challenged by the editors to think big and show the relevance of their work to other disciplines. The focus became the impact of partial melting on processes ranging from grain scale to crustal scale. As for all issues, the guest editors worked hard with their international cast of authors to bring you six stimulating papers. JOHN VALLEY, PRINCIPAL EDITOR 2012–2014 John Valley has accepted our invitation to join the editorial team, starting officially in January 2012. He will replace Hap McSween, whose term ends at the end of 2011. We will welcome John formally in the first issue of 2012. In the meantime, he is being integrated into the team and participates in all discussions. IMPACT FACTOR 2010 Elements’ 2010 impact factor was 3.105. Interestingly, Elements’ five-year impact factor is 3.561. This probably reflects the fact that articles are cited over several years. The most cited articles from the time of publication to July 2011 are: • Geisler T, Schaltegger U, Tomaschek F (2007) Re-equilibration of zircon in aqueous fluids and melts. Elements 3: 43-50 (70 citations) • Harley SL, Kelly NM, Moller A (2007) Zircon behaviour and the thermal histories of mountain chains. Elements 3: 25-30 (64) • Charlet L, Polya DA (2006) Arsenic in shallow, reducing groundwaters in southern Asia: An environmental health disaster. Elements 2: 91-96 (59) • Cartigny P (2005) Stable isotopes and the origin of diamond. Elements 1: 79-84 (51) E LEMENTS • Morin G, Calas G (2006) Arsenic in soils, mine tailings, and former industrial sites. Elements 2: 97-101 (42) • Ohtani E (2005) Water in the mantle. Elements 1: 25-30 (36) • Self S, Thordarson T, Widdowson M (2005) Gas fluxes from flood basalt eruptions. Elements 1: 283-287 (32) • Lumpkin GR (2006) Ceramic waste forms for actinides. Elements 2: 365-372 (32) • O’Day PA (2006) Chemistry and mineralogy of arsenic. Elements 2: 77-83 (31) • Rubatto D, Hermann J (2007) Zircon behaviour in deeply subducted rocks. Elements 3: 31-36 (30) • Bruno J, Ewing RC (2006) Spent nuclear fuel. Elements 2: 343-349 (30) “NUCLEAR FUEL CYCLE” ISSUE I mentioned in the April issue that, after the Fukushima nuclear accident, we made the “Nuclear Fuel Cycle” issue freely available on our GeoScienceWorld site (www.elements.geoscienceworld.org) and on Elements’ website at www.elementsmagazine.org. This was advertised as widely as possible across our network, thanks to the efforts of Barb Dutrow and the members of the Executive Committee. Did it work? Yes, there was a spike of at least one order of magnitude in downloads from GeoScienceWorld for all articles in that issue. The article “Spent Nuclear Fuel” was downloaded 35 times more than in previous months. FACEBOOK At the time of writing, we had gained 182 followers on Facebook in less than two months. If you have a Facebook account, do “like” us. We will keep you posted on when issues are taken to press and mailed, and we will share timely news. Go to www.facebook.com/elementsmagazine. Pierrette Tremblay, Managing Editor 220 A UGUS T 2011 SMASHING UP STONES A critical, but often neglected, aspect of the entire geoanalytical process involves how one actually gets one’s sample from the field and back to the laboratory for analysis. Clearly collecting material that is representative of the process being studied is the fi rst critical step. But what does one do once the specimen arrives back home? I can well remember the many hours I spent as a graduate student some decades ago in the crushing lab reducing kilograms of sample down to grams of “representative” powder; this powder would be the starting material for my assigned tasks as a budding geochemist. Jaw mill to reduce to centimetre-size – puck and ring mill to reduce to coarse powder – agate ball mill to reduce to fi ne powder – hours of processing – keep everything clean – don’t contaminate, don’t fractionate… Tedious, to say the least. So what technological progress has this aspect of mineralogy/geochemistry seen of late? Over roughly the past decade interest has grown in the use of electrodynamic disaggregation. In this procedure, a highvoltage electrical impulse creates a shockwave either within the material itself or within the fluid medium – typically water – that surrounds it. This method of using “lightning strikes” to reduce walnut-size rock chips down to individual mineral grains fi rst came to my attention at the Goldschmidt 2009 meeting in Davos, Switzerland, where hardware from the Swiss company Selfrag AG (www.selfrag.com) was on display. Subsequently a paper by Giese et al. (2010) described in detail the physical process involved in the various forms of electrodynamic disaggregation and also demonstrated that the high temperatures that briefly affect the sample do not bias apatite fission-track ages. Model of the Aerodynamic Impact Reactor (patent pending). The reactor’s height is approximately 2 metres. FIGURE 1 Here I would like to describe briefly an alternative technology which I learned about a year or so ago. It is being developed by Zybek Advanced Products (www.zapmaterials.com), a small company located in Boulder, Colorado, USA. Zybek’s Aerody namic Impact Reactor (FIG. 1) employs a high-pressure air stream created by a series of impellers. Within the reactor chamber, the airflow is directed into a vortex geometry with a high-speed pneu- FIGURE 3 An example of a phosphate starting material and end product from the Aerodynamic Impact Reactor matic flow established along the margin of the vessel. Within seconds centimetre-size rock chips introduced into this environment undergo a grain-size reduction through collisions within the reactor. The processed material is ultimately ejected through a port in the base of the reaction chamber (FIG. 2). The device has been integrated with multiple cyclone separators, which allow the processed material to be binned by grain size and which also remove particulates down to roughly 1 µm grain size from the exhaust air. A number of parameters can be adjusted on this apparatus, but it is commonly set to produce grain size fractions smaller than 100 or even 50 microns. By reprocessing the coarser-grained materials separated by the cyclone, it is possible to produce ultimately a very fi ne-grained end product (FIG. 3). So what are the advantages of this new approach to sample processing? Though I have yet to see any concrete data, the method is supposed to be relatively contamination free. High processing rates of up to several metric tons per hour could be of interest to the mining industry. Compared to some of the other competing methods, the Aerodynamic Impact Reactor is energy efficient, meaning lower operating costs. It is flexible in terms of the grain-size distribution it can produce and the nature of the feed stock. In fact, the method has been applied to the processing of coal and even switch grass (FIG. 4). It tends to liberate material along grain boundaries, but it also has been found to favour high surface-to-volume ratios for the end product – a benefit if subsequent chemical treatment is planned. FIGURE 4 Scanning electron microscope images of two of the more unusual material types on which the device has been used What is the future of this technology in either the mining industry or basic research? This is hard to say as the technology has not yet been widely disseminated. Time will tell. Michael Wiedenbeck, ([email protected]) Helmholtz-Zentrum Potsdam REFERENCE FIGURE 2 Diagram of the individual components within the Aerodynamic Impact Reactor processor integrated with cyclone separators E LEMENTS Giese J, Seward D, Finlay MS, Wüthrich E, Gnos E, Kurz D, Eggenberger U, Schreurs G (2010) Electrodynamic disaggregation: Does it affect apatite fission-track and (U-Th)/He analyses? Geostandards and Geoanalytical Research 34: 39-48 221 A UGUS T 2011 PEOPLE IN THE NEWS MGPV-sponsored session entitled “Turning Up the Heat: Metamorphic Perspectives on Mineral Equilibria, Heat Transport, Tectonics, and Thermochronology” (T35). ANTHONY E. WILLIAMSJONES, LOGAN MEDALIST During last May’s joint annual meeting of the Geological Association of Canada and the Mineralogical Association of Canada in Ottawa, Anthony E. “Willy” WilliamsJones of McGill University received the Logan Medal, the Geological Association of Canada’s highest award and presented to an individual for sustained distinguished achievement in Canadian Earth science. We reproduce excerpts of the citation below. For thirty years, Willy’s influence on Canadian economic geology, and Earth science in general, has been profound. Willy is an extremely creative and innovative researcher. The scope and breadth of his research into the genesis of mineral deposits is unparalleled, not only in the array of types of mineral deposits that he and his group have tackled but also in the methodologies applied and the approaches taken. His studies of mineralizing systems have included sediment-hosted base metal mineralization, uranium, porphyry Cu–Mo, granitoid-related W–Sn–Mo, pegmatite and hydrothermal rare-element mineralization, epithermal precious metals, asbestos, fluorite, Archean gold, and modern geothermal systems. He and his group made a major research breakthrough recently by showing that both petroleum and high-temperature vapor have the ability to transport important quantities of ore-forming metals. Although Willy’s contributions to economic geology are remarkable indeed, they are even more so when considered in the context of his fundamental contributions to other fields, including environmental geology, biomineralization, igneous petrology, and volcanology. In many varied ways, Willy is a truly exceptional teacher and mentor. He has produced legions of outstanding graduate and undergraduate students, inspiring them to follow careers in Earth science. JOHN FERRY, 2011 DISTINGUISHED GEOLOGIC CAREER AWARDEE John M. Ferry, Johns Hopkins University, is the 2011 Distinguished Geologic Career Awardee of the Mineralogy, Geochemisty, Petrology, and Volcanology (MGPV) Division of the Geological Society of America. The award will be presented during the 2011 GSA Annual Meeting, Minneapolis, Minnesota, USA. The presentation will take place at the MGPV Reception (held jointly with the Mineralogical Society of America and the Geochemical Society). Dr. Ferry will give the Distinguished Geologic Career Award Lecture, “When the Heat Is Turned Up, Look Out for the Hot Water,” at the E LEMENTS Dr. Ferry is cited for his contributions to the theory of fluid–rock interactions. His science is fundamentally field-based and his tools predominantly chemical and petrological, but the insights gained have significant physical implications. His systematic evaluation of the role of fluid migration during regional metamorphism in many field areas worldwide forms the basis for understanding the long-term permeability of the middle to lower crust. He conducts careful, systematic field studies to test his and others’ models. These studies have demonstrated that different models best explain observations from individual field sites: nature is not as simple as any single model. On Earth, crustal devolatilization during metamorphism influences the mechanical strength and thermal structure of the continents and contributes to element cycling between the Earth, the atmosphere, and the oceans. Until the pioneering field studies of John Ferry and his students and colleagues, these impacts could not be realistically quantified. ED STOLPER ELECTED FOREIGN MEMBER OF THE ROYAL SOCIETY Edward Stolper is the William E. Leonhard Professor of Geology and Provost, Division of Geological and Planetary Sciences at Caltech. He was recently elected as a Foreign Member of the Royal Society. Each year 44 Fellows, 8 Foreign Members and up to 1 Honorary Fellow are elected from a group of over 700 candidates who are proposed by the existing Fellowship. Ed Stolper is renowned for his experimental and theoretical work on melting and igneous processes on the Earth, Mars and asteroids. He was the first to propose that the SNC meteorites came from Mars. He developed the “sandwich” method of multiple saturation, which enabled quantification of melting in the mantles of Earth and other planets. He developed the first quantitative model of water speciation in glasses and silicate melts and showed that water dissolves both as OH and as molecular H2O. He was the first to show that silicate crystals float in their melts at very high pressures, with implications for the differentiation of large silicate planets. He was the first to demonstrate a linear relationship between the extent of melting and source water contents in the back-arc environment. 222 A UGUS T 2011 www.wiley.com Michael Brown held academic appointments in the UK until 1990 when he moved to the University of Maryland as Professor of Geology and Chair. His research interests are in high-temperature metamorphic petrology, crustal melting, and tectonic geology. His work on migmatites and associated granites has furthered our understanding of how heat and mass are transferred within continents, and in particular the relationships between sources and sinks of melt and the importance of melt in the tectonic evolution of orogenic belts. With time his research has broadened into ultrahigh-temperature and high-pressure metamorphism, the origin of paired metamorphic belts, and secular change. Bernardo Cesare is a professor of petrology at the University of Padova (Italy), where he earned a PhD in geology in 1992 studying the Vedrette di Ries contact aureole. His research interests include lowpressure metamorphism and anatexis of pelitic rocks, fluid–melt–rock interactions in graphitic systems, fluid and melt inclusions, and the crystal chemistry of high-temperature minerals. His approach to crustal melting involves primarily the multidisciplinary study of anatectic enclaves from SE Spain and of “nanogranite” inclusions in migmatites and granulites. During the last decade he was deeply involved in coordinating the international training of early-stage researchers in metamorphic petrology. Chris Clark is a senior research fellow in metamorphic geology and geochronology at Curtin University in Western Australia. His principal research interests are in the linking of geochronology, specifically the U–Pb method using zircon and monazite, with the development of metamorphic assemblages in order to constrain the durations of mountain-building events in high-grade metamorphic terranes. Ian C. W. Fitzsimons is a professor of metamorphic geology at Curtin University in Perth, Western Australia. After an undergraduate degree at the University of Cambridge, he completed a PhD on granulite facies metamorphism at the University of Edinburgh, followed by research positions at Royal Holloway University of London, the University of Edinburgh, and Monash University. He moved to Perth in 1998, where he focuses his research on the field geology, mineralogy, petrology, and geochronology of metamorphic rocks, particularly the Precambrian granulites of Antarctica, India, and Madagascar. Simon L. Harley is Professor of Lower Crustal Processes at the University of Edinburgh, Scotland. He has over 30 years experience in metamorphic and experimental geology and geochemistry, which he has applied to understanding the high-temperature processes that take place during the evolution of continents. His approach emphasizes their chemical, isotopic, and petrographic records as preserved in minerals and mineral assemblages. He is internationally recognized as a leading authority on ultrahigh-temperature metamorphism and granulites and their implications for continental evolution. Nigel B. W. Harris, a graduate of the University of Cambridge, is a petrologist and geochemist who has studied the causes and consequences of melt production in tectonically thickened crust since his first Tibetan field campaign in 1985. He was appointed Professor of Tectonics at the Open University (UK) in 2001. In recent years his work has focused on chemical proxies for global weathering fluxes and the linkage between tectonics, orography, and climate in the Himalaya. David Healy is Lecturer in Geomechanics at the University of Aberdeen. He has research interests in structural geology, rock mechanics, tectonics, and metamorphic geology. He has a keen interest in the theory of natural rock deformation and uses quantitative models to explore the consequences of theoretical predictions in terms of field and laboratory observations. Marian B. Holness studied for both her degrees at the University of Cambridge. After periods at the University of Chicago and the University of Edinburgh, she returned to Cambridge in 1997 to take up a teaching post. Her interests are primarily in decoding the record of rock history left behind in grain-scale fabrics. She has progressed from working on volatile fluids in metamorphic rocks, through the partial melting of high-grade metamorphic rocks, and is now investigating the complex problem of solidification, in particular of gabbros. Rebecca A. Jamieson is a graduate of Memorial University of Newfoundland (PhD 1979) and is currently Carnegie Professor and Chair of Earth Sciences at Dalhousie University in Halifax, Canada. She studies interactions between metamorphic and tectonic processes at all scales using a variety of approaches, including field work, petrology, geochronology, and geodynamic modeling. She has worked on parts of the Appalachian–Caledonian, Grenvillian, and Himalayan–Tibetan orogenic belts. Her recent work has focused on the causes and consequences of melting and ductile flow in orogens and on the exhumation of ultrahigh-pressure metamorphic rocks. Timothy E. Johnson is a postdoctoral research scientist at the University of Mainz. He received his BSc (1992) and PhD (1999) from the University of Derby and held postdoctoral positions at the universities of Graz and Maryland before moving to Germany. His expertise is in metamorphic geology and mineral equilibria modeling of subsolidus and suprasolidus rocks of varying compositions and from a variety of tectonothermal environments. He has a particular interest in the generation and segregation of melt and its consequences for the compositional, thermal, and rheological evolution of the crust. Cont’d on page 227 E LEMENTS 226 A UGUS T 2011 Cont’d from page 226 Fawna J. Korhonen is a research fellow at Curtin University of Technology, Australia. She moved to this position in 2009 after a three-year postdoctoral appointment at the University of Maryland. Fawna received her BA from Carleton College and her PhD from the University of Minnesota. Her research interests include the study of polyphase high-grade metamorphism and anatexis, and the processes of mass transfer within the crust that lead to intracrustal differentiation during orogenesis. She is particularly interested in the chemical and physical effects of melting and melt loss during protracted crustal evolution, and the genetic link between residual granulites, migmatites, and granites. Claudio L. Rosenberg graduated from the State University of Milano (Italy) in 1989, where he completed an MSc thesis on the growth of K-feldspar megacrysts in granites. After a PhD in Basel (Switzerland) on the emplacement and solid-state flow of the Bergell pluton (Central Alps), he moved to Giessen (Germany) where he studied the fabrics of synkinematic, partially melted rock using experimental analogues. Based on these experiments and studies of natural migmatitic fabrics, he described the modes of localization and melt segregation and the rheological changes during deformation of melting crust. He is now at the Freie Universität Berlin (Germany), where he works on the syncollisional exhumation of the Alpine chain. Edward W. Sawyer received his first degree from the University of Southampton. He then worked for the Geological Survey of South Africa in Namibia for six years and obtained a master’s degree from the University of Cape Town. He then moved to Canada and received a PhD from the University of Toronto, followed by postdoctoral research at the Geological Survey of Norway. He returned to Canada in 1986 to take a post at the Université du Québec à Chicoutimi, where he is now a professor. His principal research interest is in migmatites and the segregation and migration of anatectic melt in the continental crust. Gary Stevens graduated with BSc and MSc degrees from Rand Afrikaans University in Johannesburg and received his PhD degree from the University of Manchester in 1995. Following this, he spent 5 years at the University of the Witwatersrand, where the Economic Geology Research Unit kindly indulged his research interests in petrology. For the past 10 years he has been employed at Stellenbosch University, where he holds the position of South African Research Chair in Experimental Petrology. His main research interests are the origins of the continental crust, partial melting of the crust, and the processes that shape granite chemistry. Martyn J. Unsworth has been a professor of geophysics at the University of Alberta in Edmonton, Canada, since 2000. He holds a BA in natural sciences (1986) and a PhD in marine geophysics (1991), both from the University of Cambridge. His research focuses on the use of electromagnetic geophysics to study continental dynamics. His recent studies have been in the Tibetan Plateau, eastern Anatolia, Taiwan, and the Canadian Cordillera. He makes use of the magnetotelluric method to study the composition of the crust and mantle in regions undergoing deformation. He has also worked on the use of these geophysical techniques in environmental and geothermal applications. Richard W. White is a professor of metamorphic geology at the University of Mainz, Germany. He received his BSc and MSc from the University of Sydney and his PhD from Macquarie University (Sydney) in 1998. He spent nine years at the University of Melbourne in several postdoctoral positions, undertaking mineral equilibria modeling studies, focusing on partial melting. He then moved to Germany, where his main interests center on high-temperature metamorphic processes, the development of mineral and melt activity–composition models, and their application to natural examples. He is currently an editor of the Journal of Metamorphic Geology. Karel Schulmann started his career in 1987 at the Czech Geological Survey in Prague. From 1991 to 2004 he was chair of the Department of Structural Geology and Petrology of Charles University in Prague. Since 2004 he has held the position of professor of geology and tectonics at the University of Strasbourg. His research interests include the structural geology and tectonics of orogenic collisional systems, metamorphic petrology, metamorphic microstructures and textures, rock fabrics, orogenic processes such as the exhumation of orogenic lower crust, the mechanisms of lower crustal flow, and the accretion of juvenile crust in the Central Asian Orogenic Belt. Christine S. Siddoway received her BA from Carleton College and MSc from the University of Arizona. Following her PhD from the University of California, Santa Barbara, she completed a Fulbright postdoctoral research fellowship at the University of Siena (Italy). She has been an investigator in the U.S. Antarctic research program since 1990, during which time she has examined the history of breakup between West Antarctica and New Zealand, the evolution of the active margin of East Gondwana, and the deformation and metamorphism of mid-crustal rocks in transcurrent settings. She is on the faculty of the Geology Department at Colorado College and served as chair during 2007–2010. E LEMENTS 227 A UGUS T 2011