Search

Earth-based telescopic data provides information on the mineralogy of the Martian surface. Data was collected during the 1986 and 1988 Earth-Mars oppositions between 3 µm and 5 µm to study carbonates. sulfates. and hydrates. The 1986 data was at 3% spectral resolution with a spatial spot diameter of 2000 km and covered a wavelength region between 2.5 µm and 4.2 µm. The 3 µm bound water band was clearly observed and an upper limit of 3 - 5 wt% carbonate was established for the regions measured based on comparisons with laboratory mixtures of carbonates and Mauna Kea palagonite, a Martian soil analog. The 1988 data had 1/3% spectral resolution between 3.2 µm and 5.1 µm with a 900 km spatial resolution. These data indicate that their is substantial variation (20 %) in the depth of the 3 µm bound water band which is not correlated with atmospheric absorptions. Faint(