Aqueous alteration in S-N-C meteorites and implications for weathering products on Mars

Is shergottite, nakhlite, and chassignite (SNC) meteorites are rocks propelled to earth by large meteoroid impacts on Mars, then it is possible to deduce much about Martian igneous petrology and geochemistry. Because SNCs are igneous rocks, however, it was not obvious that they could reveal much about sedimentary and soil petrology and low-temperature geochemistry of Mars. It is important, though, that at least four of eight SNCs carry evidence for low-temperature, extraterrestrial weathering product phases. Evidence is reviewed for Martian weathering and alteration products in SNCs and possible inferences for volatile/regolith interactions, regolith mineralogy, and sinks for the putative hidden volatiles on Mars are outlined.