Um grande dilúvio em Marte. Na Terra... nem pensar, Juvenal!!!

segunda-feira, julho 01, 2013

Fill and spill of giant lakes in the eastern Valles Marineris region of Mars

Nicholas H. Warner1,*, Mariam Sowe2, Sanjeev Gupta1, Alexander Dumke2 and Kate Goddard1

- Author Affiliations

1Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK

2Institute of Geological Sciences, Planetary Sciences and Remote Sensing, Freie Universitaet Berlin, Malteserstrasse 74-100, D-12249 Berlin, Germany

↵*Current address: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109, USA; E-mail:

The existence of Hesperian age (3.7–3.4 Ga) surface water bodies on Mars is a contentious issue, often conflicting with favored climate models. Extensive lakes are proposed to have filled parts of Valles Marineris during this period, yet evidence for their presence and temporal continuity is poorly constrained. Here we report geomorphic and chronologic evidence for the initiation and demise of a voluminous lake system within the basins of eastern Valles Marineris. We find that independent, kilometer-deep lakes were present here well after the wetter, global climate optimum that characterized the previous Noachian epoch (4.1–3.7 Ga). Relative and impact crater chronologies of flood channels emerging from lake basins indicate relatively late lake spillover in the Early Amazonian (ca. 3.0 Ga). Drawdown of the lake and cessation of interbasin sedimentation may be recorded by a similar Early Amazonian (ca. 3.1 Ga) crater retention age on the surface of Capri Mensa, a 4-km-tall, sulfate-bearing interior layered deposit. The topography data demonstrate that incision of the bedrock barriers between the basins during spillover was driven by a dramatic local base-level difference between the lake surface and downstream basin floors. We postulate that the lake spillover process created an integrated drainage routing system between a voluminous equatorial water supply and the northern plains basin.

Received 25 October 2012.

Revision received 14 January 2013.

Accepted 17 January 2013.

© 2013 Geological Society of America