This observation covers a small part of the plains surrounding the volcano Tyrrhena Patera.
Most of this area is covered by a thick layer of “mantling” material which hides the underlying rocks. Infrared data from the Mars Odyssey spacecraft suggested that this area is rockier than most of the region.
The center of the image is at full resolution, but the outer edges have averaged each group of 4 x 4 pixels. This reduces the amount of data that needs to be returned to Earth and helps ascertain how much resolution is actually needed to study this kind of terrain.
This observation confirms that the area is unusually rocky, with some bare patches of ancient shattered rock exposed at the surface. This image is also a good example of how the HiRISE team samples unknown terrain.
Written by: Laszlo P. Kestay (9 June 2010)
More info and image formats at http://hirise.lpl.arizona.edu/PSP_001674_1610
Image: NASA/JPL/University of Arizona