Evaluating the effect of sulfur on alteration assemblages in impact cratered terrains on Mars

A clay, namely nontronite, was recently discovered in Noachian terrains. That discovery was rapidly followed by detection of chlorite, serpentine, kaolinite, zeolites, and carbonates. All of the hydrous silicates are restricted to the Noachian terrains. Therefore, the alteration phases occur in the old, heavily cratered environment on Early Mars, which was most likely shaped in a very short period of time during the Late Heavy Bombardment. Thus, impact cratering was a very important process contemporaneous to the formation of hydrous silicates. This is especially important in the light of studies that have shown that impact craters are capable of hosting hydrothermal systems and producing alteration phases. On Mars, geologic links to impact-generated formation of alteration minerals in central peaks and modification zones of Martian craters have been found. Modeling the formation conditions of those phases demonstrates where and when these phases form in the post-impact hydrothermal environments on Mars