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P.R. Christensen (Arizona State University)
Thermal infrared spectral measurements have been made from the TES of the surface and atmosphere of Mars for over one and a half Mars years. A global map of the composition of the surface rocks, minerals, and condensates has been produced. This mapping has shown that dust-free surfaces vary spatially from mafic to intermediate volcanic rock types with varying abundances of plagioclase feldspar, clinopyroxene, volcanic glass, olivine, and sheet silicates. There is no evidence for large-scale deposits of carbonates exposed at the surface. Weathering products are not generally present above a detection limit of approximately 10%. This lack of significant chemical weathering indicates a history dominated by a cold, dry climate in which mechanical, rather than chemical, weathering was the dominant form of erosion and sediment production. Unique deposits of crystalline hematite indicate the occurrence of aqueous mineralization in limited regions under ambient or hydrothermal conditions, suggesting that liquid water was stable near the surface for a long period of time at these locales. Condensed carbon dioxide in the polar regions has three distinct endmembers, from fine-grained crystals to slab ice. Unique regions have been identified that appear to differ primarily in the grain size of carbon dioxide ice; one south polar region appears to remain as black slab ice throughout its sublimation. Daily global maps of the 3-dimensional thermal structure of the atmosphere, dust, water-ice clouds, and vapor have been produced for over one Mars year. These data provide a unique view of the atmospheric dynamics and the sources and sinks of atmospheric constituents, including a global dust storm comparable to the Mariner 9 storm seen 30 years ago.