CRISM: Clays near Mawth Vallis

Mawrth Vallis is an ancient Mars river channel (~15km wide) located along the crustal dichotomy boundary that exposes abundant light-toned layers of clay-rich rocks. Indicative of aqueous alteration, these clays may have been deposited during massive flooding events or in a shallow lake environment, but also could have been caused by in-place weathering of preexisting layered material like volcanic ash or crater ejecta. Clay minerals (or phyllosilicates) are good at preserving evidence of past life and habitable conditions, and so this area has been… [More at link]