HRSC black and white image of Louros Valles

This image was taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express during orbit 97 from an altitude of 269 kilometres. The image has a resolution of about 13 metres per pixel and is centred at 278.8° East and 8.3° South. North is at the right.

The image shows a system of sapping channels, called Louros Valles (named in 1982 after river in Greece), south of the Ius Chasma canyon which runs east to west. The Ius Chasma belongs to the giant Valles Marineris canyon system. The Geryon Montes, visible at the northern images border, is a mountain range which divide the Ius Chasma into two parallel trenches. The dark deposits at the bottom of the Ius Chasma are possibly related to water and wind erosion.

'Sapping' is erosion by water that emerges from the ground as a spring or seeps from between layers of rock in a wall of a cliff, crater or other type of depression. The channel forms from water and debris running down the slope from the seepage area. This is known from similar features on Earth, but on Mars it is thought that most of the water had probably either evaporated or frozen by the time it reached the bottom of the slope.