Impact-generated hydrothermal alteration on Early Mars in presence of CO 2

摘要: Impact-generated hydrothermal systems may have caused widespread alteration of the crust on early Mars. We previously explored range products using several Martian meteorites as crustal proxies: LEW88516, Dhofar 378, Chassigny, and Nakhla. Overall, dominating phases are oxides, hydroxides, clay minerals, other hydrous silicates. Our results match well with silicates (nontronite, chlorite) observed by OMEGA CRISM. The two most recent findings CRISM carbonates serpentine. While latter is formed in our calculations from all olivine-rich starting compositions (LEW88516, Chassigny), require CO2 (or HCO3-, CO32-) system. To evaluate effect CO2, we conducted new ALHA84001 maskelynite exposing them to same brine used before and, a second set calculations, addition 0.5 mol H2CO3. ALHA84001, because its secondary provide unique opportunity compare model mineralogical data. Moreover, it only sample ancient within suite meteorites.