Lethe Vallis is a valley in the
Elysium Planitia on Mars, located at 4° North and 206.5° West. It is 225 km long and is named after
river Lethe in
Katmai National Monument,
Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
, USA.
Lethe Vallis originates at the SE margin of the West Elysium Basin (
Cerberus Palus). West Elysium Basin probably contained a lake that was 500 km across and received water from
Athabasca Vallis. It was probably formed in just days or weeks and had a discharge about like the Mississippi. Some have suggested it was formed from lava flows, but lava would not be able to flow over such a low gradient for so long a distance.
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References
Valleys and canyons on Mars
Elysium quadrangle
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