Spectroscopic Identification of Carbonate Minerals in the Martian Dust

Thermal infrared spectra of the martian surface indicate the presence of small concentrations (2 to 5 weight %) of carbonates, specifically dom-inated by magnesite (MgCO3). The carbonates are widely distributed in the martian dust, and there is no indication of a concentrated source. The presence of small concentrations of carbonate minerals in the surface dust and in martian meteorites can sequester several bars of atmospheric carbon dioxide and may have been an important sink for a thicker carbon dioxide atmosphere in the martian past. Carbonate minerals play an important role in determining the history of the martian atmosphere, geology, and hydrology. Spe-cifically, carbonate minerals provide a trace for the presence of liquid water in the martian past and form readily in a CO2 atmosphere when water is present (1, 2)