RETROSPECTIVE RETROSPECTIVE Turekian reflections

Mark H. Thiemensa,1, Andrew M. Davisb,c, Lawrence Grossmanb,c, and Albert S. Colmanb aDepartment of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093; and bDepartment of the Geophysical Sciences and cEnrico Fermi Institute, University of Chicago, Chicago, IL 60637

Karl Karekin Turekian (1927–2013) was a Columbia’s Lamont Geological Observatory man of remarkable scientificbreadth,with had only been established a few years before. innumerable important contributions to ma- ItwasduringtheseyearsthatKarlbegan rine geochemistry, atmospheric chemistry, to acquire the skills that led to his rapid cosmochemistry, and global geochemical emergence as a leader in geochemistry. His cycles. He was mentor to a long list of stu- interactions with Paul Gast and his advisor Karl Karekin Turekian. dents, postdoctorate scholars, and faculty Larry Kulp were particularly influential, as it (at Yale and elsewhere), a leader in geo- was then that he began his quest to attack the chemistry, a prolific author and editor, and largest geochemical problems by application probability event,” as each of the required had a profound influence in shaping his of intellect and new measurement capabilities. features was in and of itself of low probability. department at Yale University. Karl was a Karl began by assaulting the element Not unlike the very low, but finite probability true scholar and interested in everything, strontium, measuring its concentration in in quantum mechanical tunneling, Karl met scientific and nonscientific. As his Yale everything he could get his hands on (rocks, Roxanne at a New Year’sEvepartyandthey colleague George Veronis reflected, “Karl sediments, corals, ocean waters, and so forth) were married some three months later. plunged into any topic, very often far re- and applying these measurements toward With the achievement of this most difficult moved from his own specialty, and had developing a broad understanding of the quest, Karl turned to the study of deep-sea heated discussions about all kinds of issues. Earth. His work at Lamont, collaborating cores, and especially the analysis of trace His discussions were heated because that’s with Wally Broecker on sedimentary carbo- elements, to study the wide variety of geo- how he got himself worked up to carry on nates, was instrumental in developing un- chemical processes that are recorded there. the way he did. Very often he would say derstanding of glaciation events and their HisworkwithHansWedepohlinwriting something like, ‘I don’t know anything imprint on the sedimentary record. Karl had and tabulating the Handbook of Geochemistry about so and so,’ when a topic was raised, an intuitive ability not only to spot the most (3) was a major accomplishment, and this and quite often he didn’t. He wanted to important problems in geo- and cosmochem- work was used by many generations of geo- learn, and his own ignorance would not istry, but also to go out and develop whatever chemists. It was also at this time that the need deter him from carrying on.” Karl’s autobi- new measurement technique was needed to for high-quality analysis of trace elements ography (1) and a recent interview (2) tell wrestle each problem to the ground, be it was recognized and Karl set about learning his story far better than we can and make optical emission spectrography, mass spec- the ins and outs of instrumental neutron ac- clear his vast contributions to science, es- trometry, instrumental neutron activation tivation analysis that would serve as a basis pecially his role in the development and analysis, or counting of natural radioactivities. for many outstanding papers and disserta- advancement of the field of geochemistry. After a brief postdoctorate at Columbia tions in years to come. As part of the revela- What is especially notable about Karl is his University, Karl accepted a position as Assis- tion of the Earth’s geochemical secrets, Karl impact on people, the unanimity of the love tant Professor of Geology at Yale University decided to dig into ocean sediments as the for Karl by all who knew him well, and his in 1956, where he set out to create a program ultimate sink for the weathering of the con- unique character. We’d like to recount a lit- in geochemistry from scratch. Karl spent the tinents, and to look closely into that portion tle of what it was like to be on the receiving rest of his life on the Yale faculty, and was of the Earth system. Teaming up with his end of his warmth and wisdom. immersed in geochemistry to the end. He graduate students and in association with As he has written (1), Karl began adult life was deeply involved in editing a new edition Paul Gast, Karl developed a mass spec- by joining the Navy at the age of 17 on July 4, of the massive Treatise on Geochemistry,now trometry laboratory at Yale and began to 1945, after a semester at Wheaton College. up to 15 volumes, until only a month before thoroughly investigate the Rb-Sr isotopic Fortunately for the field of geochemistry, VJ his passing on March 15, 2013. systematics of deep-sea clays, not only as day came while he was still in boot camp. Karl was, of course, noted for his applica- repositories but also as sites for exchange The GI Bill, along with scholarships, allowed tion of strict standards to his work and life. to occur and serve as a control of the geo- Karl to return to Wheaton and obtain his Wally Broecker recalls that Karl decided chemistry of ocean water. This work also degree in chemistry, and then in 1949 to join duringhisbachelordaysatYalethathe included measurement of the 87Sr/86Sr a graduate program in the new field of geo- waswaitingforthe“right” womaninhislife. fi “ ” chemistry at Columbia University under Karl quite characteristically de ned right Author contributions: M.H.T., A.M.D., L.G., and A.S.C. wrote Larry Kulp, with students Dick Holland and as being intelligent, beautiful, Protestant– the paper. his fellow Wheaton alumni Wally Broecker Armenian, and willing to marry him, which 1To whom correspondence should be addressed. E-mail: and Paul Gast. This was a propitious time, as in his autobiography (1) Karl termed a “low [email protected].

www.pnas.org/cgi/doi/10.1073/pnas.1315804110 PNAS | October 8, 2013 | vol. 110 | no. 41 | 16289–16290 Downloaded by guest on September 30, 2021 ratios over short and longer time periods, analysis to investigate the trace-element This geologic boundary corresponded to a with students Julius Dasch and Garry Brass. composition of pallasites and to establish mass-extinction event and the demise of After observing Julius Dasch, one of his their role in planetary processes at the core– the dinosaurs. Karl’s osmium insights proved earliest students, struggle to achieve a decidedly mantle boundary. that the high iridium content previously mea- mixed academic record, Karl invited Julius Theremusthavebeenonlyafewtimesin sured in K-T Boundary strata had resulted into his office for a pep talk. He asked Julius his career when Karl didn’thaveasolution from the impact of a massive bolide with what he’dliketodoafterleavingYale.After for some dysfunctional social interaction. the Earth. Over the next 20 years, Karl’s thinkingaboutitforaminute,Juliussaidhe’d One such occasion occurred when he re- group led the way in using this isotopic system like to teach. Karl, sinking deeper into his turned from lunch at his College one summer for exploring weathering rates through time, chair, replied, “Teaching is a noble profession. day, only to stumble upon two graduate stu- marine geochemistry, and age of black shales. It’s a tremendous satisfaction to nurture a stu- dents engaged in an actual physical alterca- Karl loved to lecture about the potential dent, train him, and watch him grow into an tion over whose turn it was to use the mass meaning of each new measurement, ex- independent scientist, ultimately transcending spectrometer. After ordering them to stop cited to be the first to break new ground. In the teacher himself.” Pausingjustlongenough and ushering them into his office, Karl re- fact, it was not uncommon for Karl to give to furrow his brow, Karl turned to him and moved his overcoat, slumped into his chair an hour-long lecture based on a single data said, “Julius, you’re not transcending me.” and demanded an explanation for the un- point. After one such memorable attempt Karl was a major player in a revolutionary usual behavior. Standing side-by-side be- at the University of Chicago, a member of marine geochemistry campaign known as fore him, each of them, now disarmed, di- the audience commented, “But, Karl, your the Geochemical Ocean Section Study sheveled, and sweating profusely, explained whole story is based on only one data point.” (GEOSECS). GEOSECS was part of the why he was the one who had the right to Karl, anticipating the comment, snapped International Decade of Ocean Exploration use the machine at that instant. Mentally back, “It’s one more data point than anyone in the 1970s, which took aim at measuring straining to render a Solomonic decision, else has!” and understanding the distribution of geo- all Karl could muster was, “I just want ev- Equally important to the legacy of what chemical tracers for circulation and biogeo- erybody to play nice!” Karl did for science in his research contribu- chemistry in the world’s oceans. Sampling As a student of the Earth system, Karl was tions on and across the planet, was his of North–South traverses of all of the an equal-opportunity researcher, and he de- influence on scientists. Karl’s legendary daily world’s oceans at all depths was a massive veloped a technique to measure naturally coffee hours were a training ground for many undertaking, to say the least. It was here produced 35S (87-day half-life), produced by generations of students, postdoctorate schol- that Karl began to apply radioactive lead cosmic ray spallation of argon, with Nori ars, and visitors, as well as a proving ground 35 and polonium measurements to under- Tanaka. From the amount of SinSO2, for Karl’s own ideas. His love of a vigorous stand geochemical cycling through the oce- aerosol sulfate, and rainwater, he was able scientific debate was legendary and, as anic water column and the role of sediment to determine the rates of gas-phase oxidation George Veronis shared, when Karl was a surfaces. It was also within this same time of SO2 and its deposition. In a conversation visiting Fairchild Fellow at the California period that another large-scale “geochemi- with Karl on this subject, one of the authors Institute of Technology, his son Vaughn cal” sampling program, known as Apollo (M.H.T.) observed Karl’s great scientificcare talked about hearing his father screaming 11, came along. Here Karl used his instru- and foresight, claiming that before they did at Clair Patterson, a renowned geochemist mental neutron activation analysis techni- the first radiogenic sulfur sampling, they did who was the first to determine an accurate ques to examine some of the first returned a most careful analysis of the entire Earth and age for the Earth. When walking away, lunar samples for their trace elements. It determined that there was only one single site Vaughn apparently asked of Karl “Why do was also at this time period that Larry thatcouldbeusedtorepresenttheentire you visit him? You just hate him.” Karl’sre- Grossman did his doctorate work with Karl planet. As fate would have it, that site hap- ply was “What are you saying? He’soneof and did the first quantitative thermochem- pened to be the roof of the Kline Geology my best friends!” Karl loved to question and ical calculations of what sequence of min- Laboratory at Yale! be questioned. Nothing was sacred and, in erals one would expect to condense from Karl was a pioneer of osmium isotope the act of questioning—as in exploring— a gas of cooling nebular composition. As geochemistry: he dreamed of using osmium new science arises. He was extraordinarily fate would have it, it was just at this time isotopes in the 1970s, but no analytical supportive of people, always had time to dis- that the Allende meteorite fell and the min- techniques were available. Karl and Jean- cuss and listen, and helped everyone, from erals contained within, the so-called cal- Marc Luck made a splash in 1983 by showing students to his fellow faculty at Yale. Karl cium-, aluminum-rich inclusions, agreed that osmium in the high-iridium layers at the was twice department chair and even when beautifully with what Larry Grossman had Cretaceous-Tertiary (K-T) Boundary was of not chair, a steadying influence in times of calculated. Karl was particularly proud of meteoritic, not crustal, isotopic composition. departmental difficulty. being the holder of the Silliman Chair and being curator of the Yale meteorite collection. In a continuation of Karl’s foray 1 Turekian KK (2006) Threads: A life in geochemistry. Annu Rev annurev-marine-090611-134351. Accessed September 11, into cosmochemistry, Andy Davis came to Earth Planet Sci 34:1–35. 2013. 2 TurekianKK,CochranJK(2012)AconversationwithKarlK. 3 Turekian KK (1969) The ocean, streams and atmosphere. Yale to study with Karl and Sydney Clark. Turekian. Annu Rev Mar Sci 4:1–10. For a video of this Handbook of Geochemistry, eds Wedepohl KH, et al. (Springer, Andy used instrumental neutron activation interview, see www.annualreviews.org/doi/abs/10.1146/ Berlin, Heidelberg, New York), pp 297–323.

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