Modeling the collapse of Hebes Chasma, Valles Marineris, Mars

Abstract

Research Article| July 01, 2011 Modeling the collapse of Hebes Chasma, Valles Marineris, Mars M.P.A. Jackson; M.P.A. Jackson † 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas, Austin, Texas 78713, USA †E-mail: martin.jackson@beg.utexas.edu. Search for other works by this author on: GSW Google Scholar J.B. Adams; J.B. Adams 2Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA Search for other works by this author on: GSW Google Scholar T.P. Dooley; T.P. Dooley 1Bureau of Economic Geology, Jackson School of Geosciences, University of Texas, Austin, Texas 78713, USA Search for other works by this author on: GSW Google Scholar A.R. Gillespie; A.R. Gillespie 2Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA Search for other works by this author on: GSW Google Scholar D.R. Montgomery D.R. Montgomery 2Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2011) 123 (7-8): 1596–1627. https://doi.org/10.1130/B30307.1 Article history received: 30 Mar 2010 rev-recd: 23 Jun 2010 accepted: 28 Jul 2010 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation M.P.A. Jackson, J.B. Adams, T.P. Dooley, A.R. Gillespie, D.R. Montgomery; Modeling the collapse of Hebes Chasma, Valles Marineris, Mars. GSA Bulletin 2011;; 123 (7-8): 1596–1627. doi: https://doi.org/10.1130/B30307.1 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 Physical modeling and detailed mapping of Hebes Chasma provide new insights into the crustal composition and origin of the Valles Marineris region of equatorial Mars. Hebes Chasma is a 315-km-long and 8-km-deep closed depression containing distinctive landforms that include diapirs and extensive allochthonous flows that end in pits. A central puzzle of Hebes Chasma is how and where 105 km3 of missing material disappeared. Our physical models tested the hypothesis that the chasma formed by collapse and removal of material from below. Gravity-driven collapse in the models reproduced all the chasma's main landforms as subsidence evolved from early sagging of the upper surface, to inward collapse and removal of material, to emergence of diapirs and low-gradient flows. The models and geologic evidence suggest that Hebes Mensa arched upward diapirically and raised deep stratigraphy almost level with the chasma rim. If the chasma indeed collapsed by subsurface drainage as occurred in the models, the upper 8–10 km of deposits at Hebes must have been solid to depths of ∼5 km but viscous at greater depths. The materials removed could not have consisted mainly of basalt flows; instead, they probably were a mixture of hydrated and nonhydrated salts, water ice, liquid water, and insoluble (likely basaltic) particles. The proportions of these constituents are unknown but constrained because the material drained from the subsiding chasma and apparently contributed to the outburst floods released down neighboring Echus Chasma and Kasei Valles. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.