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, and Venus. 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 probes and by geochemical observations of the martian meteorites. I am also studying the thermal evolution of large impact basins on the Moon and the differentiation, thermal evolution, and magmatic history of asteroid 4 Vesta.
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 am a member of the science team for NASA's GRAIL mission, which is producing a very high resolution map of the Moon's gravity field. I am using GRAIL gravity observations to understand the volcanic plumbing of features such as the Aristarchus Plateau and the Marius Hills. I collaborate on measurements of the density and porosity of lunar rocks, which provide important constraints on the gravity models. I am also using gravity and topography observations to study the evolution of Mars, with a particular focus on large highland volcanos such as Hadriaca Patera and Apollinaris Patera. Another focus of my Mars models is the structure of the Thaumasia Plateau, which is the earliest phase of the Tharsis volcanic province.
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.