Bedrock Exhumed from the Deep

Roadside bedrock outcrops are all too familiar for many who have taken a long road trip through mountainous areas on Earth. Martian craters provide what tectonic mountain building and man’s TNT cannot: crater-exposed bedrock outcrops.

Although crater and valley walls offer us roadside-like outcrops from just below the Martian surface, their geometry is not always conducive to orbital views. On the other hand, a crater central peak—a collection of mountainous rocks that have been brought up from depth, but also rotated and jumbled during the cratering process—produce some of the most spectacular views of bedrock from orbit.

This color composite cutout shows an example of such bedrock that may originate from as deep as 2 miles beneath the surface. The bedrock at this scale is does not appear to be layered or made up of grains, but has a massive appearance riddled with cross-cutting fractures, some of which have been filled by dark materials and rock fragments (impact melt and breccias) generated by the impact event. A close inspection of the image shows that these light-toned bedrock blocks are partially to fully covered by sand dunes and coated with impact melt bearing breccia flows.

Written by: Livio Leonardo Tornabene  (18 January 2017)

This is a stereo pair with ESP_012367_1695 .

More info and image formats at

Image: NASA/JPL/University of Arizona