Valles Marineris in the east of the Tharsis volcanic region
Valles Marineris in the east of the Tharsis volcanic region
The canyon system of Valles Marineris is among the most striking geological structures on Mars. The valley system, carved into the ground by geological faults, extends along the equator for almost 4000 kilometres, traversing the highlands of the Red Planet. The valleys begin in the west, on the outliers of the Tharsis volcanic region, a plateau rising as much as five kilometres above the surface of Mars, which fractured due to expansion stress and consequent up-arching. The eastern foothills of Valles Marineris are called the Coprates Chasma; they open up toward the large outflow channels that once carried vast quantities of water to the northern lowlands. Higher regions are marked red in this topographic map, while yellow and green indicate moderate elevations, and the lowest points are shown in blue.