The HiRISE camera on board NASA's Mars Reconnaissance Orbiter recorded this image of the northern reaches of a delta deposited by the Nanedi river at the bottom of a lake, in an unnamed crater in the Xanthe highlands. The horizontally stacked layers are clearly visible and are each only a few metres thick. These layers have formed in standing water over time. The area covered by this detail image is about one kilometre wide. The delta deposits have probably been formed 3.8 to 4 billion years ago. The surface is now characterised by dunes created by Martian winds.
Credit: NASA/JPL-Caltech/University of Arizona.