Staff Scientist - Planetary Geophysics
Lunar and Planetary Institute
3600 Bay Area Boulevard
Houston, TX 77058
My research focuses on the internal structure and evolution of the Moon, Mars, Venus, and differentiated meteorite parent bodies. One major area of interest is the thermal evolution of planets. My studies of Mars include simulations of magma production in mantle plumes, which are the likely cause of the geologically recent volcanism in places such Olympus Mons. I also model the long-term thermal evolution of Mars, with a focus on the crustal production rate, the mantle degassing history, and the history of the core’s magnetic dynamo. This research primarily involves computer modeling. The model results are tested by comparison with observations of gravity, topography, surface imagery, and magnetic fields obtained by NASA planetary spacecraft missions and by geochemical observations of the martian meteorites. I am also studying the differentiation, thermal evolution, and magmatic history of asteroid 4 Vesta and magma production and rifting associated with mantle plumes on Venus.
The second main emphasis of my research is using gravity and topography observations to study the structure of the crust and lithosphere of the terrestrial planets. I was a member of the science team for NASA’s GRAIL mission, which produced a very high resolution (~ 5 km/pixel) map of the Moon’s gravity field. I am using GRAIL gravity observations to understand the volcanic structure and subsurface plumbing of features such as the Gruithuisen Domes and the Marius Hills. I am also using gravity and topography observations to study the evolution of Mars, with a particular focus on large highland volcanos such as Syrtis Major and Apollinaris Mons. In support of these projects, I have measured the density and porosity of lunar and martian rocks using laser scanning and helium pycnometry in the Lunar Sample Laboratory and the Antarctic Meteorite Laboratory at NASA’s Johnson Space Center.
I am actively involved in a variety of science education programs. I have contributed to numerous summer teacher training workshops, including several that have been based at field sites in the western United States that serve as analogs for processes on the terrestrial planets (including the Channeled Scablands, the Columbia River flood basalts, Yellowstone, the Snake River Plains, the Cascade volcanos, Meteor Crater, and Mono Lake). I have also contributed to the development of a variety of education products designed for use in either formal classroom education or in informal education settings such as libraries.