Balme, M. R.; Gallagher, C. J.; Gupta, S. and Murray, J. B.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1144/SP356.11|
|Google Scholar:||Look up in Google Scholar|
Lethe Vallis is an approximately 230 km-long and 1.5 km-wide channel connecting several shallow basins in the Elysium Planitia region of Mars. It sits within a distinctive morphological unit defined by a platy-ridged-polygonized texture. We have documented the geomorphology of the system, and constructed topographical long profiles of the channel thalweg and the contacts of the platy-ridged-polygonized material. The Lethe thalweg is shallow (with a slope of about 0.0001) but contains steeper sections that match the locations of observed cataract systems. The contact profiles suggest that the small basins linked by Lethe progressively ponded and over-spilled as the system developed, the cataracts being associated with this over-spill. Other landforms observed in the system include streamlined islands, anastomosing distributary systems, fluvial hanging channels and terraces on the channel margins. There are also possible dunes and/or antidunes within the channel. These all point to catastrophic fluvial flooding. Estimates of formative discharge are of the order of 1×104–5×104 m3 s−1, similar to the discharge of the Mississippi River. We infer that Lethe Vallis formed as a fluvial ‘fill and spill’ catastrophic flood system. This demonstrates that the main Western Elysium Basin, the upstream source of Lethe Vallis, contained a substantial transient lake.
|Item Type:||Journal Article|
|Copyright Holders:||2011 The Geological Society of London|
|Academic Unit/Department:||Science > Physical Sciences
Science > Environment, Earth and Ecosystems
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Matthew Balme|
|Date Deposited:||12 Jan 2012 14:35|
|Last Modified:||16 Nov 2012 12:09|
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