This image covers materials near Gale Crater just north of the planned Mars Science Laboratory landing site.
It is possible that hydrothermal deposits formed here in association with the creation and cooling of Gale Crater billions of years ago. This material could then have been transported into the landing ellipse by fluvial processes.
Hydrothermal deposits may represent evidence for an ancient habitable environment on Mars.
Written by: Alfred McEwen (3 August 2011)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_023034_1755
Image: NASA/JPL/University of Arizona