HiRISE: Possible opaline silica in Elorza Crater

Elorza Crater is an approximately 40-kilometer diameter complex crater located at 304.8 degrees east, 8.76 degrees north, about 300 kilometers north of Coprates Chasma. This image centers on the southwestern portion of the central uplift, and is characterized by numerous bedrock exposures and coherent impact melt flows. The distinguishing feature of this central uplift is the various types of bedrock that are observable at the surface. This image shows uplifted massive fractured bedrock that is visible directly adjacent to dark-toned flow materials, which are interpreted to be impact melt flows. [More at link]