Carbonates and coated particles on Mars

The identification of carbonate deposits on Mars may be extremely useful for understanding the paleoclimate of the planet and may have very important implications on the search for extinct Martian life, owing to the high potential of carbonates to record traces of fossils. In this work, we present some results on the possible presence and detectability of coated particles produced by the photodecomposition of the outer layer of carbonate grains. Our results suggest that the photodecomposition process, if really effective in the Martian environment, should not necessarily prevent the detection of relatively large carbonate particles on the surface and in the atmospheric aerosol of Mars. The detection of carbonates is obviously more likely in particular sites of the Martian surface where geomorphological indications seem to suggest the past existence of bodies of water in which carbonate precipitation could have occurred. A list of these areas is also given.