Jerry X. Mitrovica
2015 Arthur L. Day Medal
Presented to Jerry X. Mitrovica
Citation by Chris Beaumont and Paul Hoffman
For contributions to the theory and analysis of Earth deformation associated with glacial ice sheets and mantle convection, and applications of the resulting patterns of land and sea level change to such diverse problems as ice age terminations, mantle viscosity structure, true polar wander, snowball Earth, global warming and Martian strandlines.
Receiving the Arthur L. Day Medal from the GSA is a singular honor for me. The honor is deepened by the fact that one of my closest colleagues and mentors, Richard O’Connell, who passed away earlier this year, was a past recipient of the Day Medal. And it is further deepened by its connection to my two remarkable citationists – Paul Hoffman and Chris Beaumont. In the early 1980s, Chris developed the idea that viscous flow coupled to subducting slabs could drive long wavelength tilting of continents and platform sedimentation – epeirogeny as the great geologists of the mid-20th century called it. That he gave that idea to me to explore, a graduate student he had never met, was an act of scholarly generosity that I will never forget and I will always be deeply indebted to him and my wonderful advisor, Gary Jarvis, for challenging me to understand the fundamentals and for giving my career such a good start. I also owe a great deal to Paul, who actively encouraged research at the interface between mantle dynamics and the geological record, and who promoted the work of a young graduate student that he had also never met.
All of these colleagues share a gregarious curiosity and their example is something I have tried to emulate. After all, the diversity mentioned in my citation is curiosity in all but name, and in this regard my talented graduate students and post-docs have been my constant companions. It would be dishonest of me to accept any academic award without citing their remarkable achievements.
At the University of Toronto, where I was on faculty until 2009, Russ Pysklywec’s elegant work revealed important connections between mantle flow and a suite of enigmatic sedimentary basins; Glenn Milne guided me, and everyone else, to a much deeper and more complete understanding of the physics of post-glacial sea level; and Jon Mound designed and applied an innovative sea-level test of the often contentious inferences of true polar wander from studies of paleomagnetism. Roblyn Kendall established a new state-of-the-art in ice age sea level calculations by incorporating, with the help of our Research Fellow Konstantin Latychev, complex (i.e., realistic) Earth structure; Amy Daradich explained why the Arabian Plate is tilted up to the northeast and why the rotation of Mars is (despite many suggestions to the contrary) perfectly stable; and Isamu Matsuyama, working with generous colleagues Michael Manga, Taylor Perron and Mark Richards at UC-Berkeley, revised the classic stability theory of planetary rotation and put it on much firmer footing. Finally, post-doc Mark Tamisiea’s meticulous work established sea level fingerprinting as a powerful tool for analyzing modern and ancient sea-level records.
At Harvard University, Natalya Gomez discovered and modeled an entirely new mechanism for stabilizing marine-based ice sheets and demonstrated its fundamental importance; Carling Hay and Eric Morrow (with close colleague Bob Kopp at Rutgers) brought sophisticated probabilistic techniques into the analysis of sea level rise and have deepened our understanding of both the rate and recent acceleration of that rise over both the last century and the past 3 millennia; Erik Chan demonstrated, using new theoretical tools, what rates of true polar wander are - and are not – possible, and why, and explained the enigmatic stability of Earth rotation in the past 200 million years; and Jessica Creveling, our tutor in all things geological, used Erik’s ideas to show that rapid, oscillatory true polar wander events in deep time are quite possible, despite my skepticism. More recently, Jacky Austermann’s research has bridged mantle dynamics and paleoclimate and in doing so has countered long-standing ideas concerning ice volumes at Last Glacial Maximum and the stability of the East Antarctic Ice Sheet during the mid-Pliocene Warm Period; Harriet Lau has developed and is applying an entirely new geophysical tool for imaging internal Earth structure, namely body tide based (“tidal”) tomography; and post-doc Ken Ferrier and Adrian Dalca developed the first gravitationally self-consistent method for incorporating sediment redistribution into sea-level calculations and used it to study the Indus River Basin. Finally, my newest students, Kimee Moore, Tamara Pico and Evelyn Powell, are contributing to this wonderful diversity of ideas by exploring the strange shape of Saturn’s moon Iapetus, sediment deposition and sea level change in the South China Sea, and the complex dynamics of Antarctica’s ice streams.
My long association with the Earth System Evolution Program of the Canadian Institute for Advanced Research (CIFAR), and all the great scientists that passed through it over the past 20 years, immeasurably broadened the happy sense of community I have felt throughout my career. This incredible grouping of scientists introduced me to grand, exciting problems, and instilled in me a deep belief in the transformative power of interdisciplinary research. I am not a geochemist, paleontologist, geologist or geomorphologist, but listening to their animated discussions of topics as varied as Snowball Earth, the Great Oxygenation Event, the end-Permian extinction, the Paleocene-Eocene Thermal Maximum, Cenozoic cooling, and the processes that shape landscapes from river to continent scale, among many others, has given me a profound appreciation of each of those fields and an overwhelming sense of my good fortune.
I thank all these colleagues and friends for giving me such a charmed life, and for becoming part of my family.
Finally, I dedicate this honor to my remarkable mother, who passed away earlier this year at the age of 90. She was an absolutely unique woman of great intelligence, charisma and boundless love, who valued education, humility and hard work, and who taught me to fight for what I believe in. She also admonished me to stay in school, though I don’t think she realized just how seriously - and literally - I would take that advice!