. Opportunity explored the rim and interior of this 800-meter-wide (half-mile-wide) crater from September 2006 through August 2008. The rover’s on-site investigations indicated that the bright band near the top of the crater wall was formed by diagenesis (chemical and physical changes in sediments after deposition). The bright band separates bedrock from the material displaced by the impact that dug the crater.
This view is a cutout from a HiRISE exposure taken on July 18, 2009. Some of Opportunity’s tracks are still visible to the north of the crater (left side of this cutout).
How they got a rover over that rim…
It also looks as if the (very viscous) ejecta is harder than some of the underlying material, and formed overhangs and caves. Wow.