THE GEOLOGY OF MARS – FROM FAR AND NEAR

Remote sensing measurements by orbiting and landed spacecraft and laboratory analysis of shergottite meteorites provide complementary information about the geology of Mars. Martian meteorites are basaltic and ultramafic rocks that constrain magmatic processes such as fractional crystallization, assimilation, and outgassing, as well as chronology. Chemical and spectral analyses of rocks by Mars Pathfinder allow the identification of rocks having andesitic composition, and thermal emission spectrometry and crater imagery by Mars Global Surveyor provide mineralogic, stratigraphic, and geophysical information on regional or global scales. The geologic history of Mars that emerges from meteorite studies and spacecraft data is sometimes consistent and sometimes not, but the inconsistencies help define targets for future Mars exploration.