H.C. Urey Award

About the H.C. Urey Award

The H.C. Urey Award is bestowed annually by the EAG for outstanding contributions advancing geochemistry over a career. It is named in honor of Harold Clayton Urey, an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934 and later led him to theories of planetary evolution.

The award is based on scientific excellence as well as the broader impacts candidates have made in their careers to date. Such contributions to the broader geochemical community may include but are not limited to mentorship of young scientists, outreach, encouragement of diversity and inclusion in science or exceptional editorial contributions.

The award is presented at the V.M. Goldschmidt Conference and consists of an engraved medal, an honorarium (1000 Euros), a certificate and inclusion as a Geochemistry Fellow.

We are committed to promoting the diversity of our awardees, to recognizing a wide range of different types of exceptional contribution, and we acknowledge the different career paths that lead to the achievement of such contributions.
Nominations of underrepresented groups are encouraged.

Candidates may not be nominated if they have received the Geochemical Society Goldschmidt Award for the same body of work, or if they are a member of the EAG Council or of the H.C. Urey Award Committee.

Recent changes to nominations for the H.C. Urey Award

With the goal of increasing the number of nominations as well as the diversity of nominees, the EAG Council has decided to establish a new nomination process for the H.C. Urey Award, as well as introduce self-nominations. Read more

Recipient of the 2026 Urey Award:
Ray F. Weiss

Scripps Institution of Oceanography, University of California San Diego, USA

Ray Weiss’s influence on the field of geochemistry over the arc of his career has extended from the ocean floor to the upper atmosphere. His development and application of rigorous and creative geochemical measurement techniques have advanced our understanding of ocean and deep lake circulation, hydrothermal vent geochemistry, gas solubilities in natural waters, and the global and regional distributions of atmospheric trace gases. His recent atmospheric work has led to numerous discoveries about atmospheric composition changes, with impacts on stratospheric ozone depletion, hydroxyl radical abundance, and global radiative forcing. Read more

The 2026 Urey Medal will be presented at the Goldschmidt 2026 Conference in Montréal in July.

Former recipients of the Urey Award

2025 Donald Sparks, University of Delaware, USA. The 2025 Urey Medal will be presented at the Goldschmidt 2026 Conference
2024 Janne Blichert-Toft, Ecole Normale Supérieure de Lyon & CNRS, France – Citation by Stephen Mojszis, followed by Acceptance and Award lecture by Janne Blichert-Toft (video)
2023 Bo Barker Jørgensen, Aarhus University, Denmark – Citation by Antje Boetius, followed by Acceptance and Award lecture by Bo Barker Jørgensen (video)
2022 William White, Cornell University, USA – Citation by Vincent Salters and Acceptance by William White
2021 Sachiko Amari, Washington University in St. Louis, USA – Citation (video) by Larry Nittler and Acceptance (video) by Sachiko Amari
2020 Jill Banfield, University of California, Berkeley, USA – Citation by Ken Nealson and Acceptance by Jill Banfield
2019 Eric Oelkers, GET Laboratory, CNRS, France and University College London, UK – Citation by Liane G. Benning
2018 Susan L. Brantley, Pennsylvania State University, USA
2017 Eiji Ohtani, Tohoku University, Sendai, Japan
2016 Klaus Mezger, University of Bern, Switzerland
2015 Albrecht W. Hofmann, Max Planck Institute for Chemistry, Germany
2014 Edward Boyle, Massachusetts Institute of Technology, USA
2013 Igor Tolstikhin, Russian Academy of Sciences
2012 Alexander Halliday, University of Oxford, UK
2011 Donald E. Canfield, University of South Denmark, Denmark
2010 Charles Langmuir, Harvard University, USA
2009 François Morel, Princeton, USA
2008 Pascal Richet, IPGP, France
2007 Harry Elderfield, Cambridge University, UK
2006 Herbert Palme, Senckenberg Research Institute, Germany
2005 Alexandra Navrotsky, University of California, Davis, USA
2004 Harold C. Helgeson, University of Berkeley, USA
2003 Nicholas Shackleton, University of Cambridge, UK
2002 Grenville Turner, University of Manchester, UK
2001 Keith O’Nions, Imperial College London, UK
2000 Donald DePaolo, University of Berkeley, USA
1999 John Edmond, Massachusetts Institute of Technology, USA
1998 Jean-Guy Schilling, University of Rhode Island, USA
1997 Geoffrey Eglinton, University of Bristol, UK and John Hayes, Woods Hole Oceanographic Institution, USA
1995 Samuel Epstein, California Institute of Technology, USA, Robert N. Clayton, University of Chicago, USA and Hugh P. Taylor, Jr., California Institute of Technology, USA
1990 Wallace S. Broecker, Columbia University, USA and Hans Oeschger, University of Bern, Switzerland

An “outstanding / exceptional / profound contribution(s)” encompasses one or various combinations of the following contributions:

a series of publications (including any combination of papers, edited volumes, authored books, written reports, other writing) that represents outstanding contribution
an innovative breakthrough
teaching and training the next generation of geochemists
improvements to infrastructure and techniques
capacity building - especially in developing countries or emerging disciplines
significant contributions to building of the community such as through meeting organisation, building peer-networking groups, other positive initiatives, and tangible efforts that advance diversity, equity, and inclusion
work with policy makers to ensure that their decisions are grounded in rigorous science
curation of significant sample collections and databases of long-term scientific value
communication of the intrinsic excitement of our field to the general public, where innovative and / or connecting with traditionally underrepresented or underserved people will be considered a plus
exceptional editorial contributions

Career Paths

The European Association of Geochemistry recognizes that there are diverse research career paths, as well as the challenges of managing a research career alongside other personal commitments, possible chronic illness, and/or disability. When reviewing applicants’ eligibility and research experience, the societies will take into consideration - where reported with brevity in nomination packages - time spent working on a part-time basis and/or outside of the research environment. If a nominee has been reported to have worked part-time, they should briefly state the percentage of full-time equivalent hours that they observed and the time period it pertains to.

Where nominees have had a career break, worked outside of scientific research (where relevant to the nominee’s assessment category), taken formal periods of maternity, paternity shared parental and adoptive leave as the primary care giver, or extended/repeated sick or bereavement leave, this will be taken account of by awards committees. Each case will be considered individually.

Ray F Weiss, Scripps Institution of Oceanography, University of California San Diego, USA

Recipient of the 2026 Urey Award

RAY F. WEISS is a Distinguished Professor of Geochemistry Emeritus at the Scripps Institution of Oceanography, University of California San Diego, where he has been for 62 years. For roughly the first half of his academic career his research focused on chemical tracers in oceanography and on applying analytical chemistry methods to this research. Among his earlier contributions were the systematic quantification of gas solubilities in water and seawater that are still used today. His remote sampling of elevated temperature near-bottom waters at the Galapagos spreading center in the Eastern Pacific for measurements of helium isotopes and other geochemical tracers provided the first proof-of-existence of deep-sea hydrothermal vents. In the Weddell Sea, he carried out the first geochemical study of the sub-surface and ice-edge Antarctic mixing processes that play a major role in deep water formation for the world oceans. And in the wider Pacific, Atlantic and Indian Oceans, he and his students and postdocs developed the practical application of measuring dissolved atmospheric chlorofluorocarbons to determine the rates of ventilation, transport and mixing in the deep oceans. These studies included the first applications of time-dependent tracers in deep western boundary currents and deep equatorial countercurrents. This aquatic tracer work was also expanded to studies of mixing rates and biological productivity in deep temperate lakes, and to an improved understanding of how the P-V-T properties of water control deep mixing in these lakes.

Since many of the time-dependent tracers used in oceanography come from the atmosphere, and with the growing awareness of the environmental impacts of anthropogenic emissions to the atmosphere, the second half of Prof. Weiss’s research career shifted toward atmospheric trace gas research. He carried out the first accurate quantification of the global increase and latitudinal distribution of atmospheric nitrous oxide, an important greenhouse gas and stratospheric ozone depleting substance. With the discovery of the dominant role of chlorine- and bromine-bearing anthropogenic gases in the catalytic destruction of stratospheric ozone, and the resulting passage of the Montreal Protocol, it became important to verify by direct atmospheric measurement whether its resulting restrictions were being followed by the signatories. In 1990, Prof Weiss joined with Massachusetts Institute of Technology (MIT) colleague Prof. Ronald Prinn to lead the experimental component of the Advanced Global Atmospheric Gases Experiment (AGAGE), now a 13-nation collaboration to measure and model the distributions and lifetimes of more than 55 chemically and radiatively important trace gases emitted into the global and regional atmosphere. AGAGE has played a major role in the discovery and quantification of unreported or under-reported emissions, especially from East Asia, and in showing that some of these spurious emissions have subsequently been remediated.

Prof. Weiss has mentored graduate students and postdocs who now research and teach atmospheric and oceanic chemistry around the globe. He has authored or co-authored 273 research publications, and he has served on a wide range of advisory and review committees. He is a Fellow of the American Geophysical Union and of the American Association for the Advancement of Science.

Donald Sparks, University of Delaware, USA

Recipient of the 2025 Urey Award

DONALD L. SPARKS, S. Hallock du Pont Chair Emeritus and Francis Alison Professor at the University of Delaware, where he has spent his entire 45 year career. He is internationally recognized for his research in the areas of kinetics of geochemical processes, surface chemistry of natural materials, and impacts of climate change on cycling of metals, carbon, and nutrients in soil and water environments. Dr. Sparks pioneered the application of kinetics to soils, developing methods ranging over a wide time scale and elucidating reaction mechanisms for sorption, desorption, precipitation and dissolution processes. He was one of the first geoscientists to employ synchrotron radiation to determine sorption mechanisms of metals and nutrients at the soil mineral/water interface and speciation of metal contaminants in soils. One of the major discoveries made in these studies was that metals such as Ni and Zn could form mixed-metal aluminum hydroxide precipitates (layered double hydroxide phases, LDH) on mineral surfaces and in contaminated field soils. In a myriad of studies spanning over a 20 year period, the kinetics and mechanisms of LDH formation and stability were determined. Using innovative quick X-ray absorption spectroscopy, the Sparks group determined that the LDH phases could occur on minute time scales similar to two-dimensional adsorption processes. Once aging of the LDH phases occur, the metal (e.g., Ni and Zn) becomes sequestered such that its mobility and bioavailability is significantly diminished. Over the past 15 years, Dr. Sparks’ research has focused on the impacts of climate change e.g., flooding, sea level rise, and salinity on carbon complexation with minerals and cycling of toxic metal(loid)s and nutrients in the Earth’s Critical Zone. Synchrotron-based tools (STXM- NEXAFS) were used to determine associations of carbon with other elements in soils and carbon speciation. Additional studies used FT-ICR-MS to determine the temporal molecular fractionation of dissolved organic matter on iron hydroxide surfaces.

Dr. Sparks is the author of three textbooks, 12 edited books, and 370 refereed papers and book chapters. He is a fellow of five scientific societies, including the Geochemical Society and the European Association of Geochemistry and he has been the recipient of major awards and lectureships including the Geochemistry Medal from the American Chemical Society, the Liebig Medal from the International Union of Soil Sciences, Pioneer in Clay Science award from the Clay Minerals Society, an Einstein Professorship from the Chinese Academy of Sciences, the Soil Science Research Award from the Soil Science Society of America, the Environmental Quality Award from the American Society of Agronomy, and the Philippe Duchaufour Medal from the European Geosciences Union. Dr. Sparks was the recipient of the Alison Award, the highest faculty award, and an Honorary Doctor of Science Degree from the University of Delaware. One of the highlights of his career has been the mentoring of 65 graduate students and 35 postdoctoral researchers. Dr. Sparks served as president of the Soil Science Society of America and the International Union of Soil Sciences and as chair of the U.S. National Academy of Sciences (NAS) Committee for Soil Sciences.

Janne Blichert-Toft, Ecole Normale Supérieure de Lyon & CNRS, France

Recipient of the 2024 Urey Award

Janne Blichert-Toft is a Research Director with the CNRS at the Ecole Normale Supérieure de Lyon (ENS Lyon, France). Following M.Sc. (1990) and Ph.D. (1993) degrees obtained at University of Copenhagen, with much time spent at Lamont-Doherty Geological Observatory of Columbia University, she was awarded one of the first European Marie-Curie Post-Doctoral Fellowships to study at ENS Lyon. She was appointed by the CNRS at ENS Lyon in 1997, and defended her HDR dissertation at Université Claude Bernard, Lyon 1, in 2000. Over the years, she has been fortunate to spend extended periods of time as an invited professor at University of California Berkeley, Harvard University, California Institute of Technology, The Australian National University, Cambridge University, Tokyo University, University of Chicago, and Rice University. She was awarded Fellowship of the Geochemical Society and the European Association of Geochemistry in 2010, the American Geophysical Union in 2012, and the Mineralogical Society of America in 2023, and has been a member of the Royal Danish Academy of Sciences and Letters since 2016. She is also the recipient of medals, prizes, and awards from the CNRS, the French Académie des Sciences, the French CEA, the French BRGM, the Danish Geological Society, the Geological Society of London, the European Geosciences Union, the American Geophysical Union, and the European Association of Geochemistry.

Janne is a geochemist and an analyst specializing in radiogenic and stable isotopes with applications to geochronology, terrestrial and planetary mantle-crust-core evolution and mantle dynamics, mantle geochemistry, crustal growth and lithospheric dynamics, early Earth geodynamics, planetology, cosmochemistry, meteoritics, and ore geology, with a thematic shift over the last 15 years into new arenas of anthropology, geoarcheology, archeology, archeometry, numismatics, and ancient history.

Janne is perhaps best known for advancing the measurement and application of the Lu-Hf isotope system by multiple-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) in geochemistry, cosmochemistry, and planetary science. She showed the enormous power of this isotope system for constraining the origin, formation, and evolution of the Earth, the Moon, Mars, asteroids, and the early Solar System. Her work opened up new research trajectories that shaped the paths for geochemistry and cosmochemistry in the quest to reveal and quantify processes from the mineral to the planetary scale. She also used the revolutionizing new technique of MC-ICP-MS to reinvigorate Pb isotopes with high-precision measurements of a wide array of geological and archeological materials to address important questions, old and new, in the geochronology of the early Solar System and its solid planetary-type bodies, as well as terrestrial geodynamics, hominid evolution, oil formation, and archeological and historical issues so far only documented by ancient texts.

Janne had the privilege of being Editor of G-Cubed for ten years and, for the last decade has had the ongoing privilege of being Editor of Geochemical Perspectives and Associate Editor of Geochimica et Cosmochimica Acta. She is also the Principal Editor for Geochemistry of Elements Magazine, another privilege and a different challenge.

Additional information and a list of publications can be found here.

Bo Barker Jørgensen, Aarhus University, Denmark

Recipient of the 2023 Urey Award

Bo Barker Jørgensen is a professor of Geomicrobiology at Aarhus University, Denmark. He was the founding director of the Max Planck Institute for Marine Microbiology in Bremen, Germany, and head of the Center for Geomicrobiology at Aarhus University. He is a member of the National Academy of Sciences, USA.

Research Statement

My research focus is on the biogeochemistry and microbial ecology of marine sediments - from microscale to global perspectives. I use radiotracers combined with geochemical analyses to unravel processes of the sulfur and carbon cycles and determine their interactions and quantitative significance. Over the years, this approach has demonstrated the important contribution of sulfate reduction for the mineralization of sediment organic matter and for the anaerobic oxidation of methane. The approach has revealed the key role of sulfur disproportionation reactions and quantified the importance of sulfide oxidation for oxygen consumption in the seabed. The data have also revealed cryptic cycling of sulfur and methane.

Through the IODP, I have been deeply engaged in the exploration of the deep sub-seafloor biosphere. In the Center for Geomicrobiology, we studied this important component of the global biosphere and demonstrated how deeply buried microorganisms thrive under extreme energy limitation with generation times of up to thousand years. Their slow metabolism in million-year-old sediments control the balance between burial and mineralization of organic matter over geological time. By diverse DNA-sequencing techniques for phylogenetic and functional genes we have shown how these communities assemble already in near-surface sediments and become specialized only at depth. To conserve energy, they possess genes involved in the repair of critical macromolecules in the cells, for example to combat the racemization of amino acids.

The main objective of my current research remains to unravel the sulfur and methane cycles. We try to understand and reconcile the discrepancy between modeled and experimentally measured process rates and their use in global budgets. We study how the opposite processes of methane production and methane oxidation are controlled in the seabed, and which are the microorganisms responsible for cryptic methane cycling. We test the potential role of conductive minerals as capacitors by extracellular electron transfer in bacteria and archaea.

Additional information and a list of publications can be found here.

William White, Cornell University, USA

Recipient of the 2022 Urey Award

William White's research has focused on using radiogenic isotope ratios to understand the sources of volcanism and the large-scale evolution of the Earth’s mantle.

His interest in isotope ratios was first stimulated as an undergraduate student at the University of California Berkeley in a course taught by John Verhoogen. Later, as a graduate student at the Graduate School of Oceanography of the University of Rhode Island, when his dissertation advisor, Jean-Guy Schilling, offered him a chance to work with Stan Hart at Carnegie Institution of Washington doing Sr isotopic analyses of basalts from the Mid-Atlantic Ridge and the Azores, he jumped at it. In trying to make sense of the various dissertation data he had collected back at URI, he read Dick Armstrong’s papers and it occurred to him that partially melting mid-ocean ridge basalt could reproduce the trace element patterns he saw in Azores basalts.

Upon completing his dissertation, he returned to Carnegie to work as a post-doc with Al Hofmann for two years. He then spent a year at USGS Denver working with Mitsunobu Tatsumoto before Al hired him as a staff scientist at the new geochemistry department at the Max Planck Institut in Mainz. There, ideas from his dissertation work matured into papers Al and him wrote on what would become the now standard paradigm of mantle plumes returning subducted oceanic crust to the surface.

He returned to the US five years later, taking a faculty position at Oregon State University before moving to Cornell University where he has remained, interrupted by sabbaticals at ENS Lyon, universities in Rennes and Brest and, once again, Carnegie. He continues to work on unravelling the mysteries of magma generation and volcanism on oceanic island and island arc volcanoes and what they can reveal about how the Earth works. At Cornell, in addition to introductory earth science and oceanography, he taught classes in geochemistry and isotope geochemistry. What began as handout notes for those latter classes matured over the years into textbooks.

Additional information and a list of publications can be found here.

Sachiko Amari, Washington University in St. Louis, USA

Recipient of the 2021 Urey Award

Sachiko Amari is a research professor of Physics at Washington University in St. Louis, USA. She is also a visiting scientist at Geochemical Research Center at The University of Tokyo, Japan. She is a fellow of The Meteoritical Society since 2000 and a member of Japan Geoscience Union.

Research Statement

"I study primitive meteorites to probe the history of the early solar system and beyond. Two of my main research interests are presolar grains and volatiles in the solar system.

Presolar grains are dust grains formed in the stellar outflow or ejecta and remain largely intact in meteorites and other extra-terrestrial materials. The study of these presolar grains has opened up a new field of astronomy. By examining these grains using various instruments, we have learned nucleosynthesis in stars, mixing in stellar ejecta, temporal variation of isotopes and elements in the Galaxy, and grain condensation in stellar ejecta.

I, with my colleagues, have separated carbonaceous presolar grains from meteorites using chemical and physical methods, and study isotopic ratios of those grains using secondary ion mass spectrometry to better understand processes in stars and stellar outflow. Of the carbonaceous presolar grains, my focus in recent years has been graphite grains. We learned that two major stellar sources of graphite grains are asymptotic giant branch stars and supernovae. In collaboration with astrophysicists, we investigate nucleosynthetic processes in these stars from isotopic signatures of graphite grains.

I am also interested in the origin of volatiles, especially noble gases, in the solar system. The majority of heavy noble gases in primitive meteorites are contained in a very small portion of carbonaceous material named Q for quintessence. Ureilites are known for their igneous features yet they contain abundant noble gases whose elemental and isotopic patterns are strikingly similar to those of Q. I am very much interested in how noble gases that are very similar to each other were trapped into two kinds of meteorites, which experienced very different processes in the early solar system."

Additional information and a list of publications can be found here.

Susan L. Brantley, Pennsylvania State University

Recipient of the 2018 Urey Award

Susan L. Brantley is Distinguished Professor of Geosciences in the College of Earth and Mineral Sciences at Pennsylvania State University, where she also is Director of the Earth and Environmental Systems Institute. She has been a member of the faculty at the University since 1986 and director of the Institute since 2003.

Research Statement “I investigate questions related to the chemistry of natural waters and how these waters create or occlude porosity in rocks and soils. I studied the fundamentals of thermodynamics and kinetics of aqueous geosystems with David Crerar at Princeton University where I measured the kinetics of mineral-water reactions. While working with Art White of the U.S. Geological Survey in Menlo Park California, I began focusing on why reaction rates in the laboratory are faster than in the field. This led me to focus on how rocks transform into soil. To answer these questions, I investigated how micro-organisms, soil gases, erosion, topography, organic and inorganic solutes, rock structure, and climate impact rock weathering reactions. Putting all these observations together resulted in a new discipline – critical zone science, the interdisciplinary science that investigates the entirety of the earth surface layer from the outer limits of vegetation down to ground water. With colleagues including Ray Fletcher, Marina Lebedeva, Jacques Schott, Yves Godderis, Jerome Gaillardet, Peter Lichtner, Carl Steefel, and Li Li, I worked to develop or explore models to describe the interactions of rock, water, gas, and biota while comparing them with observations from hydrology, geomorphology, geochemistry, geology, soil science, and ecology. We have discovered that we can trace biogeochemical reaction fronts in the subsurface to interpret patterns of water flow, water chemistry, and water partitioning in catchments. Such patterns can also be related across scales from the mineral grain to watersheds. Most recently, I have become interested in the giant rock-water experiment begun in 2004 in Pennsylvania: hydraulic fracturing of the Marcellus shale formation. By working with large water quality datasets we are learning how this new industry impacts water resources, but we are also discovering the important geological controls on natural water chemistry at regional scales.”

Eiji Ohtani, Tohoku University, Sendai, Japan

Recipient of the 2017 Urey Award

Eiji Ohtani is Emeritus Professor of Department of Earth Science, Tohoku University, Sendai, Japan. Currently, he is also Distinguished Affiliated Professor, University of Bayreuth, Germany, Visiting Research Scientist of Sobolev Institute of Geology and Mineralogy, Russian Academy of Science, Novosibirsk, Russia, Guest Professor at the China University of Geosciences (Wuhan), China, and Visiting Professor of Center for Integrated Research and Education of Natural Hazards, Shizuoka University, Shizuoka, Japan.

Research Statement "My research carrier started in the late 1970’s by supervision by Mineo Kumazawa on the study of melting of silicate systems under the deep upper mantle and transition zone conditions to study melting processes occurred in the deep mantle such as deep terrestrial magma ocean in the early Earth, komatiite magmatism and melting at the base of the lower mantle. This direction was encouraged by Ted Ringwood during my stay at Australian National University (ANU) in early 1980’s, and it is still my main research direction. This direction further developed by collaboration with my young colleagues such as Akio Suzuki to study of the physical properties of magmas at high pressure to clarify the density-crossover between magma and crystals in the deep upper mantle and also at the core-mantle boundary (CMB). During the time of these studies, I worked as an engineer to introduce and to set up multi-anvil high pressure apparatus to several places such as ANU in 1982-1984, Ehime University in 1980-1988 (now developed as GRC directed by Tetsuo Irifune), consultation of a large volume press at BGI in 1995, and introduction of a large volume multianvil apparatus at Novosibirsk in 2014. We started the use of sintered diamond anvils for pressure generation by the multianvil apparatus with many colleagues including Tetsuo Irifune who showed a remarkable success on sintered diamond technology recently. Collaborating with young colleagues, who were mainly my graduate students, I made contributions to understanding the role of water in the deep earth interior. We discovered new hydrous minerals stable at the lower mantle such as hydrous phase G (reported simultaneously as phase D by the research group lead by Geophysical laboratory and BGI) and hydrous phase δ-AlOOH. Our recent exciting contribution on this topic is a discovery of δ-AlOOH-phase H (MgSiO(OH)₂) solid solution coexisting with bridgmanite and post-perovskite, an important carrier of water to the base of the lower mantle. By collaborating with an excellent seismologist, Dapeng Zhao, we clarified the hydrogen localities in the mantle transition zone, and presented a model of the deep dehydration and formation of dense hydrous magmas at the base of the upper mantle. We made extensive studies on high pressure polymorphs of olivine and silica minerals in shocked meteorites by using intense synchrotron X-ray and transmission electron microscopy (TEM). The idea of this study on meteorites originates from communications with Armed ElGoresy, Tom Sharp, and Dave Rubie during my stay in BGI in 1995. By collaboration with an excellent TEM mineralogist, Masaaki Miyahara, we reported stishovite, and seifertite in lunar meteorites and a recovered Apollo sample, and the decomposition of olivine into ferropericlase and bridgmanite in shocked Martian meteorites for the first time. My recent research focused on the constitution and formation of the Earth’s core. Collaborating with Seiji Kamada and others, I studied phase and melting relations of the iron-light elements (Si, O, H, and S) systems and metal-silicate partitioning at the conditions relevant to the central region of the Earth. By collaborating with Tatsuya Sakamaki, Hiroshi Fukui, and Alfred Q.C. Baron and others, we are now making challenging measurements of compressional velocity of hcp-Fe and Fe-light element alloys at extreme conditions exceeding160 GPa and 3000 K using a double-sided laser-heated DAC combined with inelastic X-ray scattering." Additional information and a list of publications can be found here.

Klaus Mezger, University of Bern, Switzerland

Recipient of the 2016 Urey Award

Klaus Mezger is a professor of Isotope Geology in the Department of Geological Sciences, University of Bern, Switzerland. “My early research focused on the study of metamorphic processes in crustal rocks to understand their evolution as a function of pressure, temperature and time. This involved the use of radioactive decay schemes in metamorphic minerals for understanding the possible geologic significance of the ages provided by these chronometers. This helped to quantify the rates of processes that modify the continental crust and also yielded time constraints on events in deep crustal rocks involved in orogenic cycles. With the advent of ICPMS technology, our research group at the University of Münster expanded the capability to measure high precision isotope ratios and trace element abundances in terrestrial and extraterrestrial rocks and minerals. The development of new analytical methods is a significant driving force in the advancement of geochemistry, since it allows to measure new parameters that further our understanding of geo- and cosmochemical processes. Newly developed and improved analytical techniques opened up new opportunities to study the genesis and evolution of Earth`s continental crust and mantle and provided new insights into the chemical and isotopic evolution of the solar system from the condensation of the first matter to planet formation and their early differentiation. These studies revealed an unexpectedly short time span for the formations of the earliest planets after the start of condensation in the solar system. Studies of heavy stable isotope variations, or their lack thereof, in different meteorites classes revealed the conditions of condensation of the solar nebula, the causes for volatile element depletion and the importance of radial mixing in an evolving planetary system. The research at the University of Bern focusses on the chemical and isotopic studies of terrestrial and extraterrestrial material in order to reveal the conditions that lead to the formation of habitable planets.”

Albrecht W. Hofmann, Max Planck Institute for Chemistry in Mainz, Germany

Recipient of the 2015 Urey Award

Albrecht “Al” Hofmann is Emeritus Director of the Geochemistry Division of the Max Planck Institute for Chemistry in Mainz, Germany. Currently, he is also Adjunct Professor and Visiting Senior Research Scientist at Lamont-Doherty Earth Observatory, Columbia University, New York, Adjunct Professor at the University of Nanjing, China, and Guest Professor at the China University of Geosciences in Wuhan, China. Research Statement “After an early focus on geochronology and diffusion kinetics my interests shifted toward isotope and trace element geochemistry of Earth’s mantle and to questions of crust-mantle evolution. Together with Bill White, I embraced Jason Morgan’s mantle plume hypothesis as a mechanism to recycle subducted ocean crust and thereby explain the geochemical differences between ocean island basalts and mid-ocean ridge basalts. Later, I teamed up with mantle dynamicists Uli Christensen and Cinzia Farnetani, and with Alex Sobolev, to interpret specific geochemical heterogeneities seen in hotspot volcanism. In the dynamical models, the thermal boundary layer at the base of the mantle plays a key role as a place where former ocean crust is segregated and stored and ultimately re-entrained by rising plumes. In the work with Sobolev, we use melt inclusions to identify specific lithologies such as recycled pyroxenites in basalt sources. As our ability to analyze a wide range of highly incompatible elements in mantle-derived basalts developed since the 1980s, starting with spark source mass spectrometry and continuing with ICPMS technology, our team at the Mainz MPI, with the analytical support of Klaus Peter Jochum, identified a series of specific trace element ratios, now called “canonical”, which show little or no systematic changes over absolute concentration ranges of up to three orders of magnitude in basalts. Thus, canonical ratios reflect the respective source ratios, some of which, notably (Nb,Ta)/(Th,U) and Pb/(Ce, Pr), are highly useful tracers of continental/arc-related versus normal-mantle related sources. Together with isotope ratios, such canonical trace element ratios help us trace the long-term evolution of the crust-mantle system.” Also see Albrecht W. Hofmann's Curriculum Vitae, list of publications and Google Scholar page.

Edward Boyle, Massachusetts Institute of Technology

Recipient of the 2014 Urey Award

My main job description is marine geochemist, using trace element chemistry and isotopic composition to understand how elements move through the ocean, the role trace elements play in biogeochemical cycling, and how they have varied through time due to natural (ice age cycles) and anthropogenic forcing, using corals and fossils in sediments. Over the years, this work has led me into related areas, including ice core chemistry and river and estuarine chemistry. The work involves devising new sampling techniques for contamination-free sampling of trace metals in the ocean, and more efficient methods for trace metal analyses on small samples. My research group and I spend a fair amount of time at sea (I have been out at sea for two years of my life). Examples include studies of natural cadmium in the ocean and carbonate fossils, investigations into the nature (colloidal vs. soluble) and distribution of iron in the ocean, studies demonstrating anthropogenic inputs of metals into southern Spain coastal waters and the Mediterranean Sea, and documenting the fate of anthropogenic Pb in the marine environment during the past three decades. This includes work on stable (Fe and Zn) and radiogenic (Pb) isotope ratios. Following these paths has also led me to consider the role of the ocean and evolving ocean chemistry in forcing atmospheric carbon dioxide changes.

Igor Tolstikhin, Russian Academy of Sciences

Recipient of the 2013 Urey Award

My life and professional carrier were highly influenced by several people and it is worth presenting them. These are first of all my parents, Nestor and Matil’da Tolstikhin: thanks to their activity, I grew up in a very “earth science environment”. Professor Erik Gerling, who is amongst the top experts in cosmo-geochemistry, introduced me to the importance of isotope science. By the choice of Destiny (I thank her for this!), I met Jan Kramers and we friendly worked together for about two decades; several papers and the book “The evolution of matter” (2008) are a direct result of our collaboration. During 2.5 years, Keith O’Nions was my teacher at Cambridge and Oxford. In the 21st century, my most visited place in the world became the Max Plank Institute of Chemistry at Mainz, with Al Hofmann being my friend, my colleague, and my hospitable host. These and many other contacts with Russian, European and American scientists developed my research activity which now includes noble gas mass-spectrometry, isotope cosmo-geochemistry, isotope hydrology, modelling of the Earth’s chemical evolution. I’ve always tried to understand “How does Nature work?” using isotopic compositions of the elements in natural materials. Some answers to this question were obtained thanks to the discovery of solar helium in the deep earth interior (1969). Other important early helium-related results were: the first proposal to use tritium-helium-3 systematic for dating of terrestrial waters (1969); the precise measurement of helium isotope composition in the atmosphere (the only isotopic constant done in Russia, 1970); the Earth degassing models taking into account presence of solar noble gases in the mantle (1975); using the C/3He ratio to study fluxes of major volatile species, e.g. carbon (1976); the model of helium dissipation from the Earth’s atmosphere envisaging fluxes of solar-like mantle helium (1981). Simultaneously I’ve been studying sources, sites and mobility of noble gas isotopes in rocks and minerals of different origin, age and composition, as well as helium residence times and fluxes within rock (mineral) – pore water – movable ground water system (1976 – 2011). In middle of the 1970s, chemical transport models of the earth fractionation, degassing and core segregation attracted my and Irma Azbel’s attention (1975 – 1993) and later on I continued these studies with other colleagues; this resulted in the chemical Earth model with whole-mantle convection (2005 – 2008).

H.C. Urey Award

About the H.C. Urey Award

Recipient of the 2026 Urey Award:Ray F. Weiss

Scripps Institution of Oceanography, University of California San Diego, USA

Former recipients of the Urey Award

An “outstanding / exceptional / profound contribution(s)” encompasses one or various combinations of the following contributions:

Career Paths

Ray F Weiss, Scripps Institution of Oceanography, University of California San Diego, USA

Recipient of the 2026 Urey Award

Donald Sparks, University of Delaware, USA

Recipient of the 2025 Urey Award

Janne Blichert-Toft, Ecole Normale Supérieure de Lyon & CNRS, France

Recipient of the 2024 Urey Award

Bo Barker Jørgensen, Aarhus University, Denmark

Recipient of the 2023 Urey Award

William White, Cornell University, USA

Recipient of the 2022 Urey Award

Sachiko Amari, Washington University in St. Louis, USA

Recipient of the 2021 Urey Award

Susan L. Brantley, Pennsylvania State University

Recipient of the 2018 Urey Award

Eiji Ohtani, Tohoku University, Sendai, Japan

Recipient of the 2017 Urey Award

Klaus Mezger, University of Bern, Switzerland

Recipient of the 2016 Urey Award

Albrecht W. Hofmann, Max Planck Institute for Chemistry in Mainz, Germany

Recipient of the 2015 Urey Award

Edward Boyle, Massachusetts Institute of Technology

Recipient of the 2014 Urey Award

Igor Tolstikhin, Russian Academy of Sciences

Recipient of the 2013 Urey Award

Recipient of the 2026 Urey Award:
Ray F. Weiss