Continental-scale salt tectonics on Mars and the origin of Valles Marineris and associated outflow channels

Abstract

Research Article| January 01, 2009 Continental-scale salt tectonics on Mars and the origin of Valles Marineris and associated outflow channels David R. Montgomery; David R. Montgomery † 1Quaternary Research Center, Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195-1310, USA, Astrobiology Program, University of Washington, Seattle, Washington 98195-1310, USA †E-mail: dave@ess.washington.edu Search for other works by this author on: GSW Google Scholar Sanjoy M. Som; Sanjoy M. Som 1Quaternary Research Center, Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195-1310, USA, Astrobiology Program, University of Washington, Seattle, Washington 98195-1310, USA Search for other works by this author on: GSW Google Scholar Martin P. A. Jackson; Martin P. A. Jackson 2Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78713-8924, USA Search for other works by this author on: GSW Google Scholar B. Charlotte Schreiber; B. Charlotte Schreiber 3Quaternary Research Center, Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195-1310, USA Search for other works by this author on: GSW Google Scholar Alan R. Gillespie; Alan R. Gillespie 4Quaternary Research Center, Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195-1310, USA Astrobiology Program, University of Washington, Seattle, Washington 98195-1310, USA Search for other works by this author on: GSW Google Scholar John B. Adams John B. Adams 5Quaternary Research Center, Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195-1310, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2009) 121 (1-2): 117–133. https://doi.org/10.1130/B26307.1 Article history received: 10 Aug 2007 rev-recd: 16 Feb 2008 accepted: 14 Mar 2008 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation David R. Montgomery, Sanjoy M. Som, Martin P. A. Jackson, B. Charlotte Schreiber, Alan R. Gillespie, John B. Adams; Continental-scale salt tectonics on Mars and the origin of Valles Marineris and associated outflow channels. GSA Bulletin 2009;; 121 (1-2): 117–133. doi: https://doi.org/10.1130/B26307.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A synthesis of deformation patterns within and around the Thaumasia Plateau, Mars, points to a new interpretation for regional deformation and the origin of Valles Marineris and associated outflow channels. The morphology of the Thaumasia Plateau is typical of thin-skinned deformation, akin to a “mega-slide,” in which extensional deformation in Syria Planum and Noctis Labyrinthus connects via lateral zones of transtension and strike-slip—Claritas Fossae and Valles Marineris—to a broad zone of compressional uplift and shortening defined by truncated craters and thrust faults along the Coprates Rise and Thaumasia Highlands. However, the low regional slope (~1°) results in gravitational body forces that are too small to deform the basaltic lava flows conventionally thought to compose the flanks of the Tharsis volcanic province. Instead, we conclude that geothermal heating and topographic loading of extensive buried deposits of salts and/or mixtures of salts, ice, and basaltic debris would allow for weak detachments and large-scale gravity spreading. We propose that the generally linear chasmata of Valles Marineris reflect extension, collapse, and excavation along fractures radial to Tharsis, either forming or reactivated as part of one lateral margin of the Thaumasia gravity-spreading system. The other, dextral, lateral margin is a massive splay of extensional faults forming the Claritas Fossae, which resembles a trailing extensional imbricate fan. The compressional mountain belt defined by the Coprates Rise and Thaumasia Highlands forms the toe of the “mega-slide.” Topographic observations and previous structural analyses reveal evidence for a failed volcanic plume below Syria Planum that could have provided further thermal energy and topographic potential for initiating regional deformation, either intrusively through inflation or extrusively through lava flow and/or ash fall emplacement. Higher heat flow during Noachian time, or geothermal heating due to burial by Tharsis-derived volcanic rocks, would have contributed to flow of salt deposits, as well as formation of groundwater from melting ice and dewatering of hydrous salts. We further propose that connection of overpressured groundwater from aquifers near the base of the detachment through the cryosphere to the martian surface created the outflow channels of Echus, Coprates, and Juventae chasmata at relatively uniform source elevations along the northern margin of the “mega-slide,” where regional groundwater flow would have been directed toward the surface. Our hypothesis provides a unifying framework to explain perplexing relationships between the rise of the Tharsis volcanic province, deformation of the Thaumasia Plateau, and the formation of Valles Marineris and associated outflow channels. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.