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Project Progress

Rationale: The Martian bright soils seem to be compositionally homogenous and globally distributed and have many unusual elemental, magnetic, and mineralogical properties that are related to their formation environment. As the volumetrically largest soil unit on Mars, its formation mechanism is central to understanding Martian climate evolution and the relative role of various geologic processes in altering the Martian surface.

Progress: Examination of existing data shows that Martian bright soils are poorly crystalline and show no evidence for carbonates or clay minerals. This may imply that the dominant weathering processes on Mars did not involve significant amounts of liquid water and casts doubt on the hypothesis that Mars may have been warm and wet for an extended period of time. If Martian climate did not have a clement period then the environments where life may have thrived in the past may be very limited. We are in the process of revising a manuscript on this topic. Weak absorption features in the 2-2.5 mm region have been interpreted as clays and may imply prolonged aqueous activity. However, the interpretation of these absorption features is complicated by the solar, Martian, and Earth atmospheres. New higher spectral resolution data collected at Kitt Peak will permit us to separate out the narrower atmospheric features from broader mineral features on the surface. This will enable us to determine if well crystalline clays are present in Martian bright soils.

Schedule: We did not meet our goal publishing of the Mars soil paper this year but expect to have it done by the end of the summer.