Nanedi Valles, a roughly 800-km valley extending southwest-northeast and lying in the region of Xanthe Terra, southwest of
Chryse Planitia. In this view, Nanedi Valles ranges from approximately 0.8-to 5.0-km wide and extends to a maximum of about 0.5 km below the surrounding plains. This valley is relatively flat-floored and steep-sloped, and exhibits meanders and a merging of two branches in the north. The valley's origins remain unclear, with scientists debating whether erosion caused by ground-water outflow, flow of liquid beneath an ice cover or collapse of the surface in association with liquid flow is responsible.
Image captured by the High-Resolution Stereo Camera (HRSC) operated by DLR onboard ESA's Mars Express on 3 October 2004 during orbit 905. North is to the right. Credit: Copyright FU Berlin/MOLA.