Planetary Geology and Geophysics

GEODYNAMICS BRANCH

Planetary Geology and Geophysics

Planetary geology and geophysical research in the Geodynamics Branch emphasizes the planet Mars, but also includes studies of the Moon, Venus and Earth. image of Mars Personnel in the Branch are CoInvestigators on the Mars Orbiting Laser Altimeter (MOLA) investigation on the Mars Global Surveyor (MGS) Mission, which was launched on November 7, 1996 and is currently on its way to Mars, and PIs in NASA's Planetary Geosciences Research and Analysis Program, and in the Planetary Instrument Definition and Development Program (PIDDP).

Comparative planetology is a major theme in both geological and geophysical investigations. For example, Cratering studies include well-known but often poorly understood terrestrial craters such as Sudbury and Zhamashin as well as the detailed morphometric analysis of martian craters which is planned as part of the Branch's involvement in the MOLA investigation. Early Crustal Evolution of Mars is an active area of study, with emphasis on the structure of large impact basins, volcanic resurfacing, and the formation of the martian crustal dichotomy. Crustal (Thickness) Structure on Mars is an area of current study, using recent gravity field models and existing topography. Fluid dynamic modeling studies of Volcanic Eruption and Flow Processes, often constrained by terrestrial examples, have application to both Venus and Mars.

Geophysical studies likewise emphasize comparative planetology. Spherical harmonic models of Global Gravity and Topography of the Moon, Mars, Venus and Earth are studied for understanding of both Crustal Structure and internal structure and dynamics. Precession, Obliquity Changes, Rotational Dynamics and their relationship to external forcing (Venus) as well as to climatic effects (Mars) have direct connection back to the study of Orbital-Rotational-Climatic Interaction on the Earth.



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Key Players

Bruce Bills, Herb Frey, Jim Garvin, Paul Lowman, Dave Rubincam, Jim Roark, Stephanie Stockman, Steve Baloga, Lori Glaze, and Susan Sakimoto

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SELECTED BIBLIOGRAPHY

Bills, B. G., Geophysical constraints on the deep interior of Mars: present status and future prospects, LPSC XXVII, 115-116, 1996.

Bills, B. G., Variations in the rotation rate of Venus due to orbital eccentricity modulation of solar tidaltorques, J. Geophys. Res. (submitted), 1996.

Bills, B. G. Discrepent estimates of the moments of inertia of the Moon, J. Geophys. Res. 100, 26,297-26,303, 1995.

Bills, B. G., The rigid body obliquity history of Mars, J. Geophys. Res. 95, 14,137-14,153, 1990.

Bills, B. G., Geodetic constraints on the composition of Mars, J. Geophys. Res. 95, 14,131-14,136, 1990.

Bills, B. G. and F. G. Lemoine, Gravitational and topographic isotropy of the Earth, Moon, Mars and Venus, J. Geophys. Res. 100, 26,275-26,295, 1995.

Bills, B. G. and R. S. Nerem, Mars topography: a spherical harmonic analysis, J. Geophys. Res. 100, 26,317-26,326, 1995.

Bills, B. G. and D. P. Rubincam, Constraints on density models from radial moments: applications to Earth, Moon and Mars, J. Geophys. Res. 100, 26,305-26,315, 1996.

Frey, H. and J. H. Roark, A multi-ring impact basin in Thaumasia, LPSC XXVI, 425-426, 1995.

Frey, H. and J. H. Roark, Impact basins in southern Daedalia: evidence for clustered impactors? LPSC XXV, 387-389, 1994.

Frey, H. V. and R. A. Schultz, Speculations on the origin and evolution of the Utopia-Elysium lowlands of Mars, J. Geophys. Res. 95, 14,203-14,213, 1990.

Frey, H. B. G. Bills, S. N. Lyons and J. H. Roark, Mars crustal thickness models from Mars50c and GMM-1, J. Geophys. Res. (submitted), 1996.

Frey, H. V., R. S. Nerem and J. H. Roark, The isostatic state of martian topography - revisited. Geophys. Res. Lett. 23, 721-724, 1996.

Frey, H., B. G. Bills, W. S. Kiefer, R. S. Nerem, J. H. Roark and M. T. Zuber, Free-air and Bouguer gravity anomalies and the martian crustal dichotomy, LPSC XXIV, 511-512, 1993.

Frey, H., C. E. Doudnikoff and A. M. Mongeon, Are Noachian-age ridged plains (Nplr) actually early Hesperian in age? Proceed. Lunar. Planet. Sci. Conf. 21, 635-644, 1991.

Garvin, G. B., The global budget of impact-derived sediments on Venus. Earth, Moon&Planets, 50/51, 175-190, 1992.

Garvin, J. B. and C. S. Schnetzler, The Zhamanshin impact feature: a new class of impact crater? Geol. Soc. Am. Spec. Paper 29, pp. 249-257, 1995.

Garvin, J. B. and J. J. Frawley, Mathematical modeling of solar system volcanoes, LPSC XXVI, 445-446, 1995.

Garvin, J. B. and R. S. Williams, Small domes on Venus: probable analogues of Icelandic lava shields, Geophys. Res. Lett., 17, 1381-1384, 1990.

Glaze, L and S. Baloga, The sensitivity of buoyant plume heights to ambient atmospheric conditions: implication for volcantic eruption column heights. J. Geophys. Res. (Atmos.), 1996.

Glaze, L., S. Baloga and L. Wilson, The transpsort of atmospheric water vapor by volcanic plumes, J. Geophys. Res. (Atmos.) (submitted) 1996.

Lowman, P. D., Field evidence for a possible endogenic origin for most Sudbury breccias, J. Geophys. Res. (submitted), 1996.

Lowman, P. D., The Sudbury Structure as a terrestrial mare basin, Rev. Geophys. 30, 227-243, 1992.

Lowman, P. D., Original shape of the Sudbury structure, Canada: a study with airborne imaging radar, Canadian J. Remote Sensing V. 17, pp. 152-161, 1991.

Rubincam, D. P., The obliquity of Mars and "climate friction", J. Geophys. Res. 98, 10,827-10,832, 1993.

Rubincam, D. P., Mars: change in axial tilt due to climate? Science, 248, 720-721, 1990.

Rubincam, D. P. and B. F. Chao, Mars secular obliquity change due to the seasonal polar caps, J. Geophys. Res. 97, 2629-2632, 1992.

Rubincam, D. P. and B. F. Chao, Variations of Mars gravitational field and rotation due to seasonal CO2 exchange, J. Geophys. Res. 95, 14,755-14,760, 1990.

Sakimoto, S. and M. T. Zuber, Effects of planetary thermal structure on the ascent and cooling of magma on Venus, J. Volc. Geotherm. Res. 64, 53-60, 1995.

Sakimoto, S. and M. T. Zuber, The spreading of variable viscosity axisymmetric radial gravity currents: applications to the emplacement of Venusian "pancake" domes, J. Fluid Mech. 301, 65-77, 1995.

Sakimoto, S., J. Crisp and S. Baloga, Eruption constraints on tube-fed planetary lava flows, J. Geophys. Res. (Planets) (submitted) 1996.

Sakimoto, S., S. Baloga and J. Crisp, Three-dimensional modelling of leveed lava flows, LPSC XXVII, 1125-1126, 1996.

Stockman, S. and H. Frey, Noachian and Hesperian modification of the original Chryse impact basin topogrpahy, Geophys. Res. Lett., 22, 1269-1272, 1995.

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Last modified on December 3, 1996