Valles Marineris

Valles Marineris

Valles Marineris stretches over 4,000 km (2,500 mi) across Mars, mostly east-west just below the equator, as seen in this Viking 1 orbiter image mosaic. The three Tharsis Montes are at left; towards the top, an ancient outflow channel stretches northward from Echus Chasma to Kasei Valles. Similar outflow channels extend from the east end of Valles Marineris towards Mars's northern lowlands.
Feature type	Fault system
Coordinates	13°54′S 59°12′W / 13.9°S 59.2°W / -13.9; -59.2
Length	over 4,000 km (2,500 mi)
Naming	Mariner 9

Valles Marineris (/ˈvælɪs mærɪˈnɛərɪs/;^[1] Latin for Mariner Valleys, named after the Mariner 9 Mars orbiter of 1971–72 which discovered it) is a system of canyons that runs along the Martian surface east of the Tharsis region.^[2] At more than 4,000 km (2,500 mi) long, 200 km (120 mi) wide and up to 7 km (23,000 ft) deep,^[3][4] Valles Marineris is the largest canyon in the Solar System.^[5]

Valles Marineris is located along the equator of Mars, on the east side of the Tharsis Bulge, and stretches for nearly a quarter of the planet's circumference. The canyon system starts in the west with Noctis Labyrinthus; proceeding to the east are Tithonium and Ius chasmata, then Melas, Candor and Ophir chasmata, then Coprates Chasma, then Ganges, Capri and Eos chasmata; finally it empties into an outflow channel region containing chaotic terrain that ends in the basin of Chryse Planitia.

It has been recently suggested that Valles Marineris is a large tectonic "crack" in the Martian crust.^[6][7] Most researchers agree that this formed as the crust thickened in the Tharsis region to the west, and was subsequently widened by erosion. Near the eastern flanks of the rift, there appear to be channels that may have been formed by water or carbon dioxide. It has also been proposed that Valles Marineris is a large channel formed by the erosion of lava flowing from the flank of Pavonis Mons.^[8]