Investigation of the strength contrast at the Moho: A case study from the Oman Ophiolite

Abstract

Research Article| August 01, 2010 Investigation of the strength contrast at the Moho: A case study from the Oman Ophiolite Janelle M. Homburg; Janelle M. Homburg 1Department of Earth and Environmental Sciences, Columbia University, Lamont Doherty Earth Observatory, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Greg Hirth; Greg Hirth 2Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Peter B. Kelemen Peter B. Kelemen 1Department of Earth and Environmental Sciences, Columbia University, Lamont Doherty Earth Observatory, Palisades, New York 10964, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Janelle M. Homburg 1Department of Earth and Environmental Sciences, Columbia University, Lamont Doherty Earth Observatory, Palisades, New York 10964, USA Greg Hirth 2Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Peter B. Kelemen 1Department of Earth and Environmental Sciences, Columbia University, Lamont Doherty Earth Observatory, Palisades, New York 10964, USA Publisher: Geological Society of America Received: 20 Nov 2009 Revision Received: 22 Feb 2010 Accepted: 24 Feb 2010 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2010 Geological Society of America Geology (2010) 38 (8): 679–682. https://doi.org/10.1130/G30880.1 Article history Received: 20 Nov 2009 Revision Received: 22 Feb 2010 Accepted: 24 Feb 2010 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Janelle M. Homburg, Greg Hirth, Peter B. Kelemen; Investigation of the strength contrast at the Moho: A case study from the Oman Ophiolite. Geology 2010;; 38 (8): 679–682. doi: https://doi.org/10.1130/G30880.1 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 We investigate the viscosity contrast between the crust and mantle by analysis of deformed gabbronorite dikes in the mantle section of the Oman Ophiolite. Our study provides a rare opportunity to directly constrain the rheological contrast between a plagioclase-rich lithology typical of the lower crust and an olivine-dominated harzburgite. We constrain deformation conditions using field relationships, geothermometry, grain size piezometry, and electron backscatter diffraction. The viscosity of gabbronorite was at least two orders of magnitude lower than the viscosity of the harzburgite, consistent with the rheological contrast between plagioclase and olivine calculated via experimental flow laws. These flow laws predict that a significant viscosity contrast exists at the crust-mantle boundary where the crustal lithology is dominated by plagioclase, or where deformation localizes within plagioclase-rich layers. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.