2018 Penrose Medal

Presented to Kent C. Condie

Citation by Bob Stern

The Penrose Medal is the oldest and most prestigious award that GSA awards and recognizes “…eminent research in pure geology, for outstanding original contributions or achievements that mark a major advance in the science of geology”. It is altogether appropriate that we recognize the many contributions that Kent Carl Condie has made to our science with this award. Kent has long been an international leader in our efforts to understand what happened in the 90% of Earth history known as the Precambrian, especially how continental crust formed during this time as well his efforts generating, compiling, and synthesizing geological and geochemical data that address these problems.

Kent spent his life moving around the western USA. He was born during the Depression and grew up in Salt Lake City and the San Francisco Bay area. His life-long love of river rafting inspired him to declare geology as his major when he entered the University of Utah in 1955. The University of Utah is where Kent joined GSA (he has been a member for a little less than half of the time that GSA has existed) and completed his BS and MS before moving to the Scripps Institution of Oceanography in La Jolla, CA to study with Al Engel. After Kent received his PhD in 1964, he and Carolyn, his wife of 55 years moved to Washington University in St. Louis. In 1970 the Condies moved to the New Mexico Institute of Technology in Socorro, where Carolyn and he raised their three children (they now have nine grandchildren and one great grandchild). Kent has supervised 10 PhD and 25 MS students and continues at New Mexico Tech as Emeritus Professor.

Over the 60 years that Kent has been a member of our society, he has focused on understanding and teaching about the old rocks. His contributions over these many decades address the origin and evolution of the continents and how Earth evolved during the Precambrian. His research begins with a sound understanding of field relations and uses geochemical, geochronological, and isotopic data for sediments, lavas, and intrusive rocks to reconstruct geological events. On this firm foundation, Kent added to our understanding of what happened in Precambrian time by generating, compiling, and synthesizing the increasingly voluminous data that was generated during the last third of the 20th century and into the 21st. Kent uses the composition of igneous and sedimentary rocks to evaluate secular changes in how these we were generated and uses the inferred changes to reconstruct Earth’s tectonic evolution. His contributions include evaluating when plate tectonics started, how Archean thermal regimes may be reflected in different crust forming processes, the meaning and significance of zircon age peaks, the origin of episodic events in the mantle, and secular changes in the chemical composition of the continental crust.

Comments from other geoscientific leaders who wrote in support of this recognition are shareworthy. Alfred Kröner (Mainz) emphasized that Kent is a “…giant among those who study the Precambrian and the continental crust.” Rick Carlson (DTM) added that Kent’s “…contributions to our understanding of continent evolution match those of leaders like Ted Ringwood’s contributions to our understanding of mantle evolution.” Roberta Rudnick (UCSB) commented that Kent is “…the great synthesizer of data related to the continental crust: its composition, how it has changed through time, and how and when it has grown.” Sam Bowring (MIT) added that “… one of Kent’s most important, visionary, and pioneering contributions was demonstrating the power of compiling, synthesizing, filtering, and interpreting large amounts of data. In many ways he was decades ahead of the formalized databases and data mining methods employed today.” Cin-Ty Lee (Rice) noted “I am several academic generations removed from Kent, but the fact that my students and I are reading his current as well as his early papers speaks loudly about his long-lasting impact on geology and geochemistry.”

Another remarkable aspect of Kent’s contributions to our science is that his audience is not limited to the professional geoscientists who continue to read his more than 500 scientific papers but also includes undergraduate and graduate students via his five sole-authored textbooks, two edited volumes, and one CD-ROM. His textbook, Plate Tectonics and Crustal Evolution, was first published in 1976 and has gone through four later editions. In addition Kent has written an introductory historical geology textbook with coauthor Robert Sloan, Origin and Evolution of Earth (Prentice-Hall, 1998), an advanced textbook, Mantle Plumes and Their Record in Earth History (Cambridge University Press, 2001), and a research treatise, Archean Greenstone Belts (Elsevier, 1981). His most recent book, written is an upper division/graduate textbook, Earth as an Evolving Planetary System (Elsevier, 2005; 2011, 2016). He also has edited two books, Proterozoic Crustal Evolution (Elsevier, 1992) and Archean Crustal Evolution (Elsevier, 1994). His interactive CD ROM, Plate Tectonics and How the Earth Works is widely used in upper division Earth Science courses in the United States and Europe.

At age 81, Kent may be slowing down a little – he stopped shooting river rapids a few years ago– but still enjoys a vigorous outdoor life. I enjoy following his exploits on Facebook where he posts photos of rocks and plants he finds on mountain hikes in New Mexico; scientifically he shows no signs of slowing down and we look forward to many more scientific contributions from him.

2018 Penrose Medal — Response by Kent C. Condie

Thank you Bob, both for recommending me to the Penrose Medal Committee and for your kind and thorough citation. Bob and I have been close friends for many years, and although we don’t always agree on our interpretations as to when plate tectonics began, we respect each other’s point of view, and continue to look for new ways to approach this difficult question. It is indeed a great honor to join the list of past Penrose Medal recipients.

My first interest in geology began in high school with Colorado River trip experiences in Southern Utah and a one-semester geology class I took at South High School in Salt Lake City. When I entered the University of Utah in 1955, I was equally attracted to the Earth and biological sciences. Lee Stokes, head of the geology department, spiked my interest in historical geology, which led to a paper in 1963 coauthored with Lee on fossil bighorn sheep. I also became interested in science and religion through discussions with Lee and my friend Fred Buchanan. After several chemistry courses, it was clear that geochemistry is where I wanted to go. At Scripps Institution of Oceanography, I became acquainted with Al Engel and worked with him on my PhD research. Two things I learned from Al: 1) field geology is equally important as a chemical analysis or geophysical measurement, and 2) don’t try to publish papers without discussing it first with your thesis advisor. I also learned that it was not a good idea to adhere too strongly to my initial interpretations of scientific observations: the main conclusion of my Masters thesis (granitization for the origin of plutons) and one conclusion from PhD thesis (Neoproterozoic diamictites are submarine mudflow deposits) turned out to be wrong. Also at La Jolla, Rama Murthy and Gordon Goles showed me the importance of precise chemical analyses. I attended a thermodynamics class taught by Nobel Laureate Harold Urey, and had the opportunity to work with him on a lunar topic for my PhD; I declined since I wanted a field oriented thesis with real rocks to study (at that time we did not have lunar samples). Although I presented my first scientific paper at the Annual GSA Meetings in New York in 1963, my first publication was in 1959 in the Sigma Gamma Epsilon journal, the Compass.

During my career I have focused on two major research areas: greenstone belts and secular changes in Earth history. I was introduced to greenstones by Al Engel in the Wyoming craton and to secular changes in a paper in 1960 by Gordon Gastil. My studies have taken me around the world, not generally where tourists go: the outback of Western Australia, Arctic Canada and Siberia, Zimbabwe, Inner Mongolia and southern India. I would like to mention several experiences with lessons learned: 1) while trying to sample greenstones in southern Zimbabwe, I was attacked by an elephant (lesson learned, given sufficient reason I can run faster than an elephant); 2) Upon returning from a very long day in the field in Inner Mongolia and very much looked forward to a shower, I found the maid in my bathroom washing grimy-oily overalls in my bathtub (lesson learned, sometimes a shower is not so important anyway); 3) Having the water go off after soaping up in the shower in a small hotel in rural Kenya (lesson learned, you can still function with a coating of soap on your body); 4) being mobbed by hundreds of peasant children in India after giving one child a coin (lesson learned: if you are going to hand out coins, you need to carry a sack full); and finally 5) as I was about to get out of the jeep to collect samples in Kenya, a baboon dropped out of tree onto the hood, then opened his mouth and placed his teeth of the windshield (lesson learned: some field-related sample biases are unavoidable).

My first academic job was at Washington University in St Louis, where I learned how to be patient with students and faculty who had different points of view from mine. Chairman Bill Johns gave me a light teaching lode, and in the 5 years I was at Wash U I directed 4 PhD students. I also learned how to rapidly decrease the enrollment in my class: give an intense, weekly thermodynamics problem set. It rapidly became clear that to survive at a university required many hours a week dedicated to writing NSF and NASA research proposals, and that to progress in research, one needs to bring in collaborators form other disciplines. My first foreign greenstone studies were in the early 1970s in South Africa, where I met the Viljoen brothers, who had recently finished field-oriented PhD theses in the now famous 3.5-Ga Barberton greenstone belt. I moved to New Mexico Tech in 1970, bringing a new research perspective to the Earth Science department. It was about this time that John Rogers (U North Carolina) invited me to join his research team to study geochemical and geochronological problems in the Archean of southern India. With my PhD student Phil Allen, we explored the geochemical changes with increasing metamorphic grade in rocks south of Bangalore. In the early 1980s I began extensive geochemical studies of Archean sediments and associated volcanics in the Kaapvaal craton in South Africa. Two of my PhD students, Dave Wronkiewicz and Clay Crow each contributed to this far-reaching study, which led to striking evidence that the continental crust became more felsic after the Archean. In 1985 I had 4 PhD students and 5 Masters students working under my direction (probably too many). I began to work on Archean rocks in China In the 1990s, which culminated in the PhD thesis of Mark Boryta on the khondalites of Inner Mongolia. In the late 1990s, I became acquainted with Bill Griffin and Sue O’Reilly at Macquarie University (Sydney, Australia) which led to a sabbatical leave at Macquarie in 2002. While there I was emerged in a world of new geochemical instrumentation, numerous projects dealing with crustal and mantle evolution, and I became associated with a large group of stimulating post-docs and grad students. I learned the new technique of laser ablation ICP-MS to analyze and date zircons, which opened up a whole new set of opportunities to study secular changes in crustal evolution. In 2009 both Chris Hawkesworth and I recognized the possibility that the zircon age peaks were preservation rather than growth peaks of continental crust, and for a short time I joined the preservation group. It was Nick Arndt who pulled me back on board, and now I am firmly with the growth group. As my database of zircon ages continued to increase it was clear I needed help to statistically analyze the results. Rick Aster showed me the importance of careful statistical analysis to evaluate zircon age distributions and we published several papers on this topic.

After retirement from NMT in the 2014, my research actually grew, both in terms of depth of existing projects, number of new projects, and collaborators. Steve Puetz has shown me the value of power spectral and cross correlation analysis to understand zircon age peak time series, and as of this year we have more than 800,000 zircon ages in our database. And working with Anne Davaille in France, I learned more about the factors leading to production of mantle plumes, and what they can and cannot explain zircon age peaks. I made a list of scientific questions in 1975, and have subsequently added questions to this list, and many of the questions I added in the 1970s are still on the list! One thing is clear for sure: as a scientific retiree I am not going to run out of research projects to work on nor am I going to run out of willing and capable collaborators to work with me on these projects.

Finally, I want to thank my wife Carolyn and my children, Tami, Linda and Nathan for putting up with my long absences during many summers. I would again like to thank all the colleagues and grad students that have worked with me over the years, regrettably too numerous to name them all. Indeed the honor of receiving the Penrose Medal for 2018 involves the work of many individuals working with me to better understand the complex geological history of the Earth’s crust and mantle. And lastly, I want to thank New Mexico Tech, and especially my colleagues in the Earth & Environmental Science Department, for providing a great environment for research and teaching.