This HiRISE image of the Solis Planum region shows a relatively recent impact crater. The crater, about 400 meters across, displays numerous meter-scale and larger rocks.
These rocks are located on the crater wall and splayed out radially on the surrounding plains. The latter boulders are part of the ejecta, material blasted out of the Martian crust by the impact. The fact that the boulders are well preserved is evidence that the crater is fairly young.
Nevertheless, some ripples are visible on the crater floor, indicating that wind has had time to mobilize fine particles (sand and granules) into bedforms.
Written by: Nathan Bridges (9 March 2009)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_011834_1605
Image: NASA/JPL/University of Arizona