Folded Layers in Melas Chasma, Central Valles Marineris

There are folded layered deposits in the southern half of this image. How did this folding occur? On Earth, rocks are commonly folded when deeply buried and subject to high heat and pressure, which can make any rock flow. Such deep burial (and re-exposure or exhumation) is unlikely at this location.

In general Mars has experienced much less vertical motion of geologic strata than on Earth. Another possibility is that these layers were soft and deformable near the surface, such as wet or icy sediments.

Written by: Alfred McEwen

Credits: NASA/JPL/University of Arizona