This beautifully contrasted infrared-color image shows an area approximately 600 by 900 meters. This is a close-up of the western Medusa Fossae formation where we can see dust-covered rocky, bedrock surfaces (beige) and a bluish-tinted sand sheet that transitions into several dunes.
The bluish sand is thought to originate from the bedrock that lies beneath the dust. If true, this has implications for the composition of the formation, which has been highly debated over the years .
Written by: Livio Tornabene, Elizabeth Silber, and Kayle Hansen (16 September 2015)
More info and image formats at http://hirise.lpl.arizona.edu/ESP_041864_1745
Image: NASA/JPL/University of Arizona