In-situ determination of the iron mineralogy of the surface of Mars

G. Klingelhöfer

Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität Mainz, Staudinger Weg 9, 55099 Mainz

Mössbauer Spectroscopy is a powerful tool for quantitative analysis of Fe-bearing materials. A Mössbauer spectrometer on the Martian surface will provide (1) identification of iron-bearing phases (e.g., oxides, silicates, sulfides, sulfates, and carbonates), (2) quantitative measurement of the distribution of iron among its oxidation states (e.g., Fe2+/Fe3+ ratio), and (3) quantitative measurement of the distribution of iron among iron-bearing phases (e.g., the relative proportions of iron in olivine, pyroxene, and magnetite in a basalt) in rocks and soils. Mars is a particularly good place to do Mössbauer mineralogy because its surface is iron rich (~20% Fe as Fe2O3 [Rieder et al., 1997]). Mössbauer spectrometers that are built with backscatter measurement geometry require no sample preparation, a factor important for in situ planetary measurements.