Details

Autor(en) / Beteiligte

• Harrison, Keith P.
• Chapman, Mary G.

Titel

6 - Episodic ponding and outburst flooding associated with chaotic terrains in Valles Marineris

Ist Teil von

• Lakes on Mars, 2010, p.163-194

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2010

Link zum Volltext

Beschreibungen/Notizen

• The Valles Marineris canyons are among the deepest of topographic depressions on Mars. As such, they may be expected to have served as sinks for a variety of mobile materials, including water, regardless of their particular formation history. The interpretation of ILD formation is not critical to the putative Valles Marineris lake considered here. Considerably more important are chaotic terrains, which may constitute the primary source of water for certain putative ancient lakes in, and near, the Valles Marineris. Chaotic terrains are large regions of fractured and subsided materials found, in several cases, at the termini of Valles Marineris canyons. Some chaotic terrains that are topographically connected to Valles Marineris canyons suggest that groundwater discharge at these terrains flooded both the canyons and the outflow channels. Such floods undoubtedly led to ponding, either locally or at points along the drainage path. Coincidence of the MOLA-derived basin overflow point with channel erosion strongly supports the ponding hypothesis. Although the most likely source of ponded water was groundwater discharge at chaotic terrain in Capri and Eos Chasmata, or at large-scale fractures bounding the Valles Marineris canyons, an alternative supply from a northern plains ocean, which has a putative shoreline at a similar elevation to the Valles Marineris paleolake, is possible. Direct production of channel floods by groundwater discharge remains difficult to explain, and the buffering effect provided by surface ponding may circumvent this problem.