The bright rocks in this image have minerals that contain water. These water-bearing minerals are found using the companion instrument on the MRO spacecraft called CRISM.
By combining the spectral data from the CRISM instrument with the high resolution visible images taken by HiRISE, scientists are able to speculate how water deposited and/or altered these rocks.
Many of the depressions in Noctis Labyrinthus contain water-bearing minerals, suggesting that water was available and persistent in this region during the Late Hesperian to Amazonian epochs on Mars, a time when the climate is believed to have been dry and cold like we see today.
This is a stereo pair with ESP_036743_1735.
Image credit: NASA/JPL/University of Arizona
Note: For more information, see PIA18632: Water-Bearing Rocks in Noctis Labyrinthus.