The steep walls of Valles Marineris sometimes fail, creating giant landslides. This provides a clean exposure of the bedrock.
This image of the north wall of Ganges Chasm reveals bedrock with diverse colors and textures, representing different geologic units .
Written by: Alfred McEwen (audio: Tre Gibbs) (7 December 2016)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_047502_1730
Image: NASA/JPL/University of Arizona