This image is along the rim of an impact crater in Meridiani and shows a lighter-toned base unit with more resistant dark-toned ridges on top.
Both units exhibit complex fracture patterns. Also evident are old dune fields that have been solidified and then fractured, as well as younger, non-solidified dune fields.
More recently, the entire area has been deeply eroded by the wind.
Written by: Jennifer Griffes (15 September 2010)
More info and image formats at http://hirise.lpl.arizona.edu/PSP_003379_1835
Image: NASA/JPL/University of Arizona