Coprates Chasma

Coprates Chasma () is a huge canyon in the Coprates quadrangle of Mars, located at 13.4° south latitude and 61.4° west longitude, part of the Valles Marineris canyon system. It is long and was named after a classical albedo feature name. It was named from the classical Greek name for the Dez River in Persia.

Near 60° W is the deepest point of the Valles Marineris system (as well as its lowest point by elevation) at below the surrounding plateau. Eastward from here there is about a 0.03 degree upward slope before reaching the outflow channels, which means that if you filled the canyon with fluid, it would create a lake with a depth of before the fluid would overflow out onto the northern plains.

Keith Harrison and Mary Chapman described strong evidence for a former lake in the eastern part of Valles Marineris, especially in Coprates Chasma. It would have had an average depth of only 842 m—much smaller than the 5–10 km depth of parts of Valles Marineris. Still, its volume of 110,000 cubic miles would be comparable to Earth’s Caspian and Black Seas. The main evidence for such a lake is the presence of benches at the level that models show is where the lake level should be. Also, the low point in Eos Chasma where water would be expected to overflow is marked by fluvial features. The features look like the flow came together at a small point and carried out significant erosion.

The bottom of the Coprates Chasma contain a large field of small pitted cones which have been interpreted as Martian equivalents of terrestrial igneous or mud volcanoes.

Recurrent slope lineae

Recurrent slope lineae are small dark streaks on slopes that elongate in warm seasons. They may be evidence of liquid water.

ESP 049955 1665rslbox.jpg, Wide view of part of Valles Marineris, as seen by HiRISE under HiWish program Box shows location of recurrent slope lineae that are enlarged in next image.
49955 1665rslcolorarrows.jpg, Close, color view of recurrent slope lineae, as seen by HiRISE under HiWish program Arrows point to some of the recurrent slope lineae.
49955 1665rsldrawing6.jpg, Recurrent slope lineae elongate when the slopes are at their warmest. Near the equator, RSL elongate on northern slopes in the northern summer and on the southern slopes in the southern summer.

Gallery

File:Top of Coprates Chasma.jpg, South rim of Coprates Chasma, image is about a kilometer wide. With enhanced IR colors, we see a portion of the very top of the south wall of the canyon, looking down onto the steep upper slopes of the canyon.
Image:Corprates Chasma Fault.JPG, Faults, as seen by HiRISE. Layers in the rock face may be from volcanic, lacustrine, and/or aeolian sediments deposited in Valles Marineris.
Image:PIA19805-SeasonalFlows-CopratesChasma-VallesMarineris-20150721.jpg, Seasonal flows on Coprates Chasma in Valles Marineris.

See also

* Lakes on Mars

References

{{Portal bar, Solar System

Coprates quadrangle
Valleys and canyons on Mars