Melas Chasma is the widest segment of the Valles Marineris canyon, and is an area where MRO has detected the presence of sulfates.

This image offers a view of an excellent contact between layered deposits that postdate the formation of Valles Marineris and possible deposits that predate the canyon’s formation. The materials are near interior layered deposits that contain sulfates and likely have hydrated minerals. At high resolution, we can have more accurate mapping of the stratigraphic relationships and contacts. Enhanced color can help to differentiate between geologic units and for mapping of sulfates.

This caption is based on the original science rationale.

Written by: HiRISE Science Team (audio: Tre Gibbs)   (15 October 2014)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_037494_1685

Image: NASA/JPL/University of Arizona