Rajdeep Dasgupta, Christian Frankenberg, J. Taylor Perron, David Lawrence Shuster, and Jessica Erin Tierney were awarded the 2014 James B. Macelwane Medal at the AGU Fall Meeting Honors Ceremony, held on 17 December 2014 in San Francisco, Calif. The medal is for “significant contributions to the geophysical sciences by an outstanding early career scientist.”
It is with great delight and surprise that I introduce David Shuster as a recipient of the Macelwane Medal—it is a great delight to recognize a young scientist who has brought unique gifts to the emerging field of thermochronology but also a great surprise to be David’s citationist after having contributed essentially nothing to his intellectual growth. My role instead appears to have been that of his number one fan. I became aware of David’s work while reviewing his early manuscripts, but we didn’t meet until years later when I approached him at a meeting to say how profoundly impressed I was with his thoughtful approach and extraordinary experimental skills. I mention this here to underscore my deep admiration of David as, to the best of my recollection, I have never done that before or since.
The development of (U + Th)/He dating of accessory minerals provided new thermochronometers for investigations of tectonic and landscape evolution but was notably limited by near-surface recoil effects and the need for bulk analysis. The former interferes with recognition of high-frequency diffusion information, and the latter precludes obtaining continuous thermal histories. David’s pioneering development of 4He/3He profiling transcended both limitations, opening up entirely new avenues of research. His investigations of time-varying erosion rates in orogenic terranes have provided the clearest views of how tectonics and climate may be linked. His discovery of proton-induced neon during sample irradiation led to a novel method to determine Ne diffusion in silicates—data essential to understanding the thermal behavior of cosmogenic chronometers. He made significant contributions to developing dating methods to assess the timing of pedogenic processes with a view to better understanding past changes in environmental conditions at the Earth’s surface. In particular, his pioneering application to iron oxides opened up the possibility of directly dating soil formation and thus the calibration of paleosol records with which to examine evidence of past climate change. Although it would have been tempting to simply reproduce the tools he had already developed when commissioning his Berkeley laboratory, David adopted the complimentary capabilities of 40Ar/39Ar dating for revealing intragrain thermochronological variations. His clever application of this method to reveal thermal histories of lunar and Martian samples resulted in standout papers documenting impact events, the effects of solar heating, and timing constraints on the lunar dynamo that are revitalizing the field.
David’s career is characterized by a unique style: an idea for a novel or refined dating method is realized through an equally inspired laboratory development that yields data understood by sophisticated application of physical modeling, ultimately leading to a new view of how a planetary body works. Thus, I believe that this award both recognizes David Shuster’s outstanding early career achievements and presages his emergence as the leading international figure in his field. Congratulations, Professor Shuster!
—Mark Harrison, University of California, Los Angeles, Calif.
Thank you, Mark, for your generous citation. I am grateful to those who nominated me and to the members of AGU for this honor. I am humbled to be in the company of four outstanding scientists who are also receiving the Macelwane Medal this year and many of my academic heroes who are past recipients.
The science I pursue is an interdisciplinary and collaborative endeavor, which benefits from colleagues and mentors too numerous to fully acknowledge here. My friend and colleague Don DePaolo first introduced me to isotope geochemistry and the joys of scientific inquiry as an undergraduate at the University of California (UC), Berkeley. Don taught me how to simplify a problem’s complexity to gain an intuitive understanding of it and the importance of the words “I don’t understand.” Don then enabled me to freely pursue my curiosity as a 21-year-old, with a research position at Lawrence Berkeley National Laboratory, where I learned noble gas geochemistry and mass spectrometry from Mack Kennedy while studying geothermal fluids and volcanic gases. Those early experiences with noble gases defined the trajectory of my career.
As a graduate student at the California Institute of Technology (Caltech), I received mentorship of outstanding geochemists, including John Eiler, Don Burnett, Ed Stolper, Jerry Wasserburg, Jess Adkins, and, of course, my Ph.D. advisor, Ken Farley. I will always appreciate their influence, and I especially thank Ken for teaching me to be rigorous, fearless, and persistent with my science. To this day, Ken is my close colleague, my friend, and always my advisor. And since we began studying meteorites and lunar rocks together as graduate students, I’ve learned much about thermochronology in trying to answer Ben Weiss’s seemingly limitless questions beginning with the word why.
Since my return to UC Berkeley, my work has benefited from the creativity of outstanding graduate students and postdocs in my research group, the penetrating questions of undergraduates in my classes, the creativity and generosity of Greg Balco, and my exceptional colleagues in the Department of Earth and Planetary Science, most especially Kurt Cuffey and Bill Dietrich. I am grateful to the Berkeley Geochronology Center and the Ann and Gordon Getty Foundation for continuing to support my laboratory at a level that is essential but increasingly uncommon and to Tim Becker for world-class laboratory support.
Finally, the love of my wife, Erin, and our beautiful daughter, Nora, provide the most gratifying balance to my life that anyone could hope for. However, when we first met in middle school, Erin could not have predicted that she would later in life become so inadvertently knowledgeable in geochemistry.
—David L. Shuster, University of California, Berkeley, Calif.