Geological Society of America

T249 Geomorphology and Landscape Evolution of Mars

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

SYN-TECTONIC SEDIMENTATION RECORDED BY COUPLED BASIN AND ALLUVIAL FAN FORMATION IN VALLES MARINERIS, MARS

Paper number: T249-10
Program: Technical Sessions
Time: 12:05 PM – 12:20 PM

Authors

Joel Davis Presenting Author
Natural History MuseumDept. of Earth Sciences, London
Peter M. Grindrod
Natural History Museum, London
Steven G. Banham
Imperial College London, London
Nicolas H. Warner
State University of New York at Geneseo, Geneso, NY
Susan J. Conway
Nantes
Sarah J. Boazman
Natural History Museum, London
Sanjeev Gupta
Imperial College London, London

Abstract

Alluvial fans provide a record for tectonic and climate regimes in extensional basins on Earth. On Mars, alluvial fans mostly occur on surfaces considered Hesperian and Amazonian (< 3.7 Ga) in age, eras regarded as mostly cold and dry, and are typically identified in impact craters, rather than basins which subsided. Here, we used high-resolution orbital HiRISE and CTX datasets to identify and characterize distinct sedimentary fans in Coprates Chasma, Valles Marineris, which may have formed in an actively subsiding basin. The channelized nature of the fan surfaces and presence of embedded impact craters are consistent with alluvial fans which accumulated intermittently. The alluvial fans occur at discrete elevations along the canyon wall, suggesting separation by repeat normal faulting. This configuration indicates that for the first time syn-tectonic sedimentation occurred during basin development, similar to extensional rift systems on Earth, despite their distinct tectonic mechanisms. Coprates Chasma is an underfilled basin, suggesting that basin subsidence was outpacing erosion, and consistent with a climate was arid. The presence of widespread faulted alluvial fans in Valles Marineris suggests the syn-tectonic sedimentation at Coprates Chasma is representative of regional processes. Our results demonstrate that fluvial processes occurred during and may be linked to the opening and modification of Valles Marineris.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-355661

© Copyright 2020 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.