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| Mars |
| Thermal evolution of Mars |
| Mars’ thermal evolution has presented an intriguing dilemma. A comparison of seemingly reasonable Martian geotherms and melting relations for mantle materials suggests the potential for significant, widespread mantle melting throughout time. While small amounts of partial melting in the mantle are reasonable (e.g., Earth), such comparisons suggested that maximum melt fractions of several tens of percent and maximum depths of melting of several hundred kilometers were possible. This idea, at first blush, appears to be contrary to the surface view of Mars with its ancient, more than 3.5 billion year old highlands covering at least 40% of the planet and the rapid decrease in volcanic resurfacing after this time. Though evidence exists for young volcanic flows (10–100 Ma) which suggests that the planet may still be volcanically active at infrequent intervals. |
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| We investigated potential conditions and evolutionary paths of the crust and mantle in a coupled thermal-magmatic system using a parameterized convection model. The basic results of our study were (1) the elucidation of the importance of the latent heat of melting in thermal evolution models, (2) Mars likely has a relatively wet (weak) mantle, (3) a near-chondritic amount of heat-producing elements is most likely, and (4) a substantial fraction of the planet's heat-producing elements may reside in the crust. |
| Global geodynamics and lithospheric structure |
 | Another aspect of our work is investigation of the Martian lithosphere using gravity and topography data returned from spacecraft missions, especially Mars Global Surveyor (MGS). We have noted the pronounced role that the Tharsis rise has played on the evolution of the Martian surface and the long-wavelength structure that it has imposed. |
| This is an area of ongoing research and among other things we are studying the the crustal and lithospheric structure in the vicinity of large impact basins in the northern hemisphere and the influence of Tharsis on the development of the Arabia dome and Hesperian contractional tectonics. |
| Relevant recent publications |
| Hauck, Steven A., II, Roger J. Phillips, Thermal and crustal evolution of Mars, J. Geophys. Res., 107, 5052, doi:10.1029/2001JE001801, (2002). Article |
| Phillips, Roger J., Maria T. Zuber, Sean C. Solomon, Matthew P. Golombek, Bruce M. Jakosky, W. Bruce Banerdt, David E. Smith, Rebecca M. Williams, B. M. Hynek, Oded Aharonson, Steven A. Hauck, II, Ancient geodynamics and global-scale hydrology on Mars, Science, 291, 2587-2591, doi: 10.1126/science.1058701 (2001). Article |
| Smith, David E., Maria T. Zuber, Sean C. Solomon, Roger J. Phillips, James W. Head, James B. Garvin, W. Bruce Banerdt, Duane O. Muhleman, Gordon H. Pettengill, Gregory A. Neumann, Frank G. Lemoine, James B. Abshire, Oded Aharonson, C. David, Brown, Steven A. Hauck , Anton B. Ivanov, Patrick J. McGovern, H. Jay Zwally, and Thomas C. Duxbury, The global topography of Mars and implications for surface evolution, Science, 284, 1495-1503, doi: 10.1126/science.284.5419.1495 (1999). Article |
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