Gale Crater contains a massive central mound of layered material that has an average vertical thickness of almost 4 kilometers (2.4 miles), making it more than twice as thick as the layers exposed along the Grand Canyon on Earth. Gale Crater is approximately 152 km in diameter.
The subimage is a small portion of a HiRISE image detailing the fine-scale layering evident in the upper mound. The layered deposits can be divided into two types: a lower mound with near-horizontal, flat layers, and an upper mound with more numerous, thinner layers (some of which have greater degree of tilt than the lower layers).
The origin of these thin, repetitive layers is unknown, but they likely reflect environmental changes that occurred while the layers were being deposited. Today, erosion by wind scour has shaped them into the stair-step pattern that is reminiscent of parts of the American Southwest.
Written by: Brad Thomson (22 October 2008)
This is a stereo pair with PSP_008002_1750 .
More info and image formats at http://hirise.lpl.arizona.edu/PSP_009927_1750
Image: NASA/JPL/University of Arizona