Valles Marineris is a system of rift like valley canyons that runs along the surface of the planet Mars east of the Tharsis region.
It is named for Latin for Mariner Valleys, named after the Mariner 9 Mars orbiter space craft of 1971–72 which discovered it.
It is more than 4,000 km long, 200 km wide and up to 7 km deep, the Valles Marineris rift system is one of the larger canyons of the Solar System, surpassed only by the rift valleys of Earth and (in length only) by Baltis Vallis on Venus.
Valles Marineris in mosaic of THEMIS infrared images from 2001 Mars Odyssey. image: NASA / JPL-Caltech / Arizona State University -
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 scale of the Valles Marineris on the planet as simulated 26°x15° 16 985 km from the surface. click image for larger version. image: starry night software
The Valles Marineris 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.
Most researchers agree that this formed as the crust thickened in the Tharsis region to the west, and subsequently may have been widened by erosion. However, near the eastern flanks of the rift, there appear to be some channels that may have been formed by water or carbon dioxide.
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