CRISM: Phyllosilicates near Syrtis Major

This image shows a site near Syrtis Major, an expansive volcanic structure. This CRISM image displays olivine-rich rocks in red and rocks rich in iron-magnesium- containing clay-like minerals called phyllosilicates in various other colors. Olivine is present in most places on Mars and reflects the volcanic nature of most crustal materials. Phyllosilicates, in contrast, show where water was present at least at one point in time. The geology around the northeastern Syrtis Major region is dominated by the Isidis impact basin just to the east… [More at link]