In the centre of the 100-kilometre-diameter Rabe Crater is a large field of black dunes, some of which are up to 200 metres high. These dark dunes are composed of fine volcanic ash. Referred to as ‘basalt dunes’ due to their volcanic mineral composition, these formations are particularly frequent on Mars. Indeed, basalts represent the most common volcanic rock found on the Red Planet. This kind of dune is a very rare occurrence on Earth, found on Hawaii, New Zealand and Iceland, for example. They only arise where volcanic activity occurs in a dry climate. The data used to create this image was acquired by the High Resolution Stereo Camera (HRSC) during orbits 2441 and 12,736 of Mars Express. The image resolution is about 15 metres per pixel.
Copyright note:
As a joint undertaking by DLR, ESA and FU Berlin, the Mars Express HRSC images are published under a Creative Commons licence since December 2014: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO. This licence will also apply to all HRSC images released to date.