This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the famous "White Rock" feature in Pollack Crater in the Sinus Sabaeus region of Mars. The light-toned rock is not really white, but its light tone caught the eye of Mars geologists as far back as 1972, when it was first spotted in images acquired by Mariner 9. The light-toned materials are probably the remains of a suite of layered sediments that once spread completely across the interior of Pollack Crater. Dark materials in this image include sand dunes and large ripples.
Source: NASA/JPL/Malin Space Science Systems
Published: November 14, 2005