 Lethe Vallis, as seen byHiRISE. Flow was from southwest to northeast. Wider part of Lethe Vallis had less erosive power, so mesas are left behind from pre-existing material. Scale bar is 500 meters long. | |
| Coordinates | 4°00′N206°30′W / 4°N 206.5°W /4; -206.5 |
|---|---|
Lethe Vallis is a valley in theElysium Planitia on Mars, located at 4° North and 206.5° West. It is 225 km long and is named afterriver Lethe inKatmai National Monument,Alaska, USA.[1] 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 fromAthabasca 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.[2]
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