Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars

Research Article| January 01, 2010 Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars Nicholas Warner; Nicholas Warner * 1Department of Earth Science & Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK *E-mail: n.warner@imperial.ac.uk. Search for other works by this author on: GSW Google Scholar Sanjeev Gupta; Sanjeev Gupta 1Department of Earth Science & Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK Search for other works by this author on: GSW Google Scholar Jung-Rack Kim; Jung-Rack Kim 2Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St Mary, Surrey RH5 6NT, UK Search for other works by this author on: GSW Google Scholar Shih-Yuan Lin; Shih-Yuan Lin 2Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St Mary, Surrey RH5 6NT, UK Search for other works by this author on: GSW Google Scholar Jan-Peter Muller Jan-Peter Muller 2Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St Mary, Surrey RH5 6NT, UK Search for other works by this author on: GSW Google Scholar Geology (2010) 38 (1): 71–74. https://doi.org/10.1130/G30579.1 Article history received: 30 Jul 2009 accepted: 09 Aug 2009 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Nicholas Warner, Sanjeev Gupta, Jung-Rack Kim, Shih-Yuan Lin, Jan-Peter Muller; Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars. Geology 2010;; 38 (1): 71–74. doi: https://doi.org/10.1130/G30579.1 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 SocietyGeology Search Advanced Search Abstract On Earth, permafrost thawing is linked to climate warming. Similarly, on Mars, permafrost degradation, described from mid-latitude and equatorial settings, is likely linked to global or regional climate change. Putative thermokarst depressions identified on Mars are widely considered to be the result of sublimation, evaporation, or thawing of an ice-rich substrate. The possibility that the depressions formed by melting of permafrost to create alas-like lakes has been recently proposed, but is controversial, owing to the lack of primary evidence for liquid filling the depressions. Here we use high-resolution Mars Reconnaissance Orbiter Context Camera images and derived topographic data to characterize possible thermokarst terrain in Ares Vallis. The terrain comprises subcircular to irregular, flat-floored rimless topographic depressions that occur at varying elevations. We report the discovery of narrow channels connecting thermokarst-like depressions that provide evidence for the previous presence of ponded liquid water. Crater counts on these surfaces indicate resurfacing that is likely related to flood deposition of water-saturated sediments in Ares Vallis during the Hesperian (ca. 3.6–3.0 Ga). We infer that thermokarst lakes formed after flooding by thawing of ice within the sediments during transient warm periods in the Hesperian, a time previously considered to be too cold to permit ice thaw. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.