2003
G.K. Gilbert Award

Roger J. Phillips
Washington University, St. Louis

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Presented to Roger J. Phillips

 Citation by Raymond E. Arvidson

It is with great pleasure that I introduce Roger Phillips, Professor of Geophysics and Director of the McDonnell Center for the Space Sciences, Washington University in St. Louis, as the 2003 G. K. Gilbert Award Winner. In reading Gilbert's papers I have been continually impressed by use of incisive field observations, followed by quantitative analyses of the observations that are designed to shed light on fundamental geological processes. Gilbert's study of the Henry Mountains, Utah, including field observations and modeling these laccoliths as "pistons" bounded by circular faults, is particularly appealing because of the nice interplay of geology and physics. Roger Phillips has followed and further developed this approach in ways that I think Gilbert would understand and approve of if he were still alive today. In fact, I suspect they would be great friends, with common interests in how planets work and how measurements of surfaces and interiors can be used to test and update quantitative, physically-based models for planetary evolution.

Roger's scientific accomplishments are extraordinary in both scope and depth, as demonstrated by publication of 135 peer-reviewed papers and book chapters covering the Earth, Moon, Mars, Venus, Mercury, and the icy satellites of the outer planets. Techniques that have been employed in his studies have focused on gravity mapping and geodynamical modeling, but have included magnetics, seismic, radar sounding, and image analyses. There are many highlights associated with his scientific career, including the first deep microwave sounding of the lunar crust as the Team Leader of the Apollo Lunar (Radar) Sounder Experiment, the first Bouguer gravity anomaly determination for Mars, developing the first gravity model and global stress calculation associated with the lithospheric load due to formation of the Tharsis Plateau on Mars, pioneering the development of Venus evolution models, leading the Basaltic Volcanism Project as Director of the Lunar and Planetary Institute, leading the Gravity Team associated with the Pioneer Venus Mission to Venus, carrying out the first Magellan analysis of the nature and distribution of impact craters on Venus, and most recently, laying out the evidence that formation of the Tharsis Plateau and associated massive volcanism controls the shape of Mars. Further, he demonstrated that the release of Tharsis volatiles fundamentally changed the climate of Mars to relatively warmer and wetter conditions. His interests and skills continue to expand, for example, as a Co-Investigator on the Mars Express MARSIS radar sounder and the Deputy Team Leader on the 2005 Mars Reconnaissance Orbiter SHARAD radar sounder. The objective for the two sounders is to map the subsurface structure of the martian crust and lithosphere, with a focus on finding evidence for water tables or horizons and mapping the distribution of subsurface ice. Roger is currently spending much of his time making sure that appropriate quantitative models will be in place and used in conjunction with the sounding data to detect and map subsurface structures and water-rock and ice-rock interfaces with a high degree of fidelity.

The planetary sciences are special in that many of the leaders in the field maintain strong relationships with NASA. The reason is that we depend on space-borne missions to acquire the data needed to understand the origin and evolution of the solar system and objects with it. In fact, NASA depends on the community and its leaders to provide the advice and guidance needed to ensure a program that is scientifically exciting and cost-effective. Roger has been a leader in providing advice and guidance throughout his career, including NASA and NRC advisory panels and panels that focused on review and selection of spaceborne instruments and experiments. In addition, he has held leadership positions at each of his home institutions, including Section Manager at the Jet Propulsion Laboratory, Director of the Lunar and Planetary Institute, Matthews Professor of Geophysics at Southern Methodist University, and Professor of Geophysics and Director of the McDonnell Center for the Space Sciences at Washington University in St. Louis.

Roger is, in my opinion, the ideal recipient of the C. K. Gilbert Award. He has a distinguished scientific track record that demonstrates a strong sense of where the new discoveries are to be made. He has combined observation and theory in ways that are very reminiscent of the approaches Gilbert used throughout his career. Further, he is a highly respected senior member of our community who is often asked and often serves in advisory capacities designed to ensure that the planetary exploration program maximizes science return and follows the most important scientific questions.

  2003 G.K. Gilbert Award - Response by Roger J. Phillips

Thanks for the very kind words, Ray. It is an honor and a privilege to receive the G. K. Gilbert award, and I thank the GSA, and the Planetary Geology Division, for this recognition. I am deeply privileged to have my name associated with G. K. Gilbert. Arvid Johnson of Purdue, a Gilbert disciple, has stated: "Perhaps Gilbert's most remarkable quality was his ability to interpret into mechanical theory what he observed in the field." I, too, have tried to work at the interface between geology and geodynamics, the former because it is the science I was drawn to first, and the latter because, in the end, I can solve equations better than I can make maps.

My path to the present has been long and tortuous. In a senior class home room in San Jose in 1957, I picked up a brochure that talked about an education in geology at the Colorado School of Mines. I had never thought of that, but I saw the possibilities of combining my interest in science and math with my love for hiking and backpacking. Besides, I (mistakenly) concluded that Golden, Colorado, was deep in the Rockies. I could go to school in the mountains! (This was the first of many geologic miscalculations that I was destined to make.) I was supposed to be headed to Berkeley, and leaving California did not please my parents, but this was offset (to them) by the financial benefits of a football scholarship. CSM was chock full of people interested in geology and geophysics, mining and petroleum, and Mines taught me how to be a problem solver in the Earth Sciences. My interests turned to mining geology, and many of my friends, including my good football/geology chum Art Pansze, went on to make careers of this. I was headed in that direction, too, and managed to do three summers of field work in the Rockies. The people I worked for at Climax Molybdenum, all economic geologists from the University of Michigan, suggested that I needed to obtain a Ph.D. That had never occurred to me either.

In 1963 I set off finally to Berkeley to obtain a Ph.D. in Mineral Exploration. There in the Department of Mineral Technology, I discovered that the exploration geochemist was uninspiring, and the exploration geologist had just retired. That left the exploration geophysicist, the late Stan Ward, who influenced me to cross over to the dark side. Stan was an EM type, who at first befuddled me with upside down triangles in equations. For several years Stan immersed me in the nuances of the telluric and magnetotelluric methods, but in the mid-1960s, Stan got the idea of flying an electromagnetic sounding experiment from the Apollo spacecraft. Swept up by the national euphoria of going to the Moon, I signed up. In the span of three years I had moved from field work on a carbonatite complex in Powderhorn, Colorado, to solving the problem of low-frequency EM wave propagation in the plasma surrounding the Moon (and hopping around on Riemann surfaces). Welcome to the Space Program!

I trundled off to JPL in 1968, still with my eye on the Apollo EM sounding experiment (which we eventually flew on Apollo 17), but eager to work on the emerging Apollo data sets, which, unfortunately, the Apollo PIs were reluctant to part with. Go figure. The exception was Bill Sjogren, who had just co-discovered mascons, and who was more than willing to share his gravity data sets. Goodbye plasma physics, and the rest, as they say, is history.

I soon discovered that I needed to know more than simple gravity modeling, so I learned about lithospheric dynamics, mantle convection, thermal modeling, rock rheology, and so on. I have applied these geodynamical concepts to the planets and tried to tie them back, in the spirit of G. K. Gilbert, to the geology we observe at planetary surfaces.

The JPL days with Fraser Fanale, Doug Nash, Jim Conel, Steve Saunders, and others were exhilarating. It was there that I met a young Ph.D. from Caltech named Mike Malin, and he and I began a long collaboration, mostly trying to figure out Venus, although his most recent contribution was helping me dig my truck out of the snow last winter in St. Louis. In 1979 I moved on to became Director of the Lunar and Planetary Institute in Houston. Those were the "urban cowboy" days, and my most lasting contribution to LPI was the invention of the LPSC chili cook-off and barbeque, an act I now profoundly regret. I assembled an eclectic group of scientists there in the early 1980s, including Ric Wendlandt, Lew Ashwal, Matt Golombek, and the late Graham Ryder.

Somehow concluding that Texas was still the place to be (perhaps it was the heat or the bluebonnets), I accepted an offer in 1982 to become the Matthews Professor of Geophysics at SMU in Dallas. Lacking planetary science companions, I hung out with an unlikely though friendly crowd (e.g., vertebrate paleontologists Lou Jacobs, Dale and Alisa Winkler; palynologist Bonnie Jacobs; and archaeologist David Meltzer), and even fiddled with archaeological geophysics. In the late 1980s we recruited Vicki Hansen as our structural geologist, and she and I came to have, after I left SMU, an enjoyable collaboration trying to unravel post-Magellan Venus. I was recruited to Washington University in the early 1990s by my citationist, Ray Arvidson, who has been a good colleague and friend over the years, is a geologist who knows physics, and has made life easy for me at Wash. U.

I have now come full circle to my graduate school days, returning to my roots in EM theory by working on the MARSIS and SHARAD Mars radars. I appreciate Roberto Seu and his comrades for introducing me to radars, the Italian way, as well as for giving me the opportunity to learn about Italian culture.

When I think back over the 40 years since I left Mines, several overriding themes come to mind. First, I was extremely fortunate in being there at the start of planetary exploration. It has been a heck of a ride, though much more is in store for me. Second, I have always tried to follow the scientific problem, paying no attention to discipline boundaries. This to me is the great joy of doing science, of trying to solve a problem. Often this has gotten me into trouble, but just as often a knowledgeable colleague has bailed me out.

But the most memorable aspect of all of this has been the camaraderie. It's the friendships across the country and across the planet that make planetary science so enjoyable. We are a strange lot, driven hard by our quest to understand the planets, exchanging e-mails at two in the morning, whining about proposal writing and proposal reviewing, and not quite believing that they would actually pay grownups to do this stuff. We are always glad to see each other, to talk science and to swap stories. My planetary friendships go back decades and this includes Sean Solomon, who always sets a rigorous tone for scientific inquiry, remembers everything, and never met a sentence he couldn't improve. Norm Sleep, Kurt Lambeck, Gordon Pettengill, and Stan Peale have been good geophysical mates along the way. And we all miss Bill Kaula, who set a standard for planetary geophysics that all of us have strived for. Catherine Johnson, a friend and collaborator, has made IGPP at Scripps a welcoming place for me. Bruce Jakosky and Mike Mellon have made me feel at home at LASP in Boulder, and have opened up my eyes to a Mars evolution that involves more than interior geophysics and tectonics. Bruce has also introduced me to the concept of a Bombay Sapphire martini, best consumed at the Hotel Boulderado on a Friday afternoon while trying to figure out what makes planetary scientists tick. John Dvorak, Sue Smrekar, Mark Wieczorek, Steve Hauck, Rich Albert, and Brian Hynek were great graduate students and taught me a lot. So did step-graduate student, and presently my post-doc, Andrew Dombard.

For more than a decade, the MOLA science team on the Mars Global Surveyor mission has been a bastion of affability, with a team spirit and enthusiasm that has gotten the best science out of the topography data set derived from the orbiting laser altimeter. It has been a privilege to be on this team, and I warmly thank Dave Smith and Maria Zuber for providing such excellent leadership. We will all carry on the party, led by Sean, as we start the journey to Mercury next year.

In closing I would like to acknowledge two really fantastic people, my daughters Kristina and Kimberly. As for my wife Rosanna, she is my best buddy, the love of my life, and, thankfully, works hard at removing my head from the planets when necessary and re-rooting me in reality.