Convection in a partially molten metasedimentary crust? Insights from the El Oro complex (Ecuador)

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Research Article| January 01, 2016 Convection in a partially molten metasedimentary crust? Insights from the El Oro complex (Ecuador) Nicolas Riel; Nicolas Riel 1Department of Earth Sciences, Durham University, Science Labs, Durham DH1 3LE, UK Search for other works by this author on: GSW Google Scholar Jonathan Mercier; Jonathan Mercier 2ISTerre, University Grenoble I, CNRS-IRD, 1381 rue de la Piscine, BP53, 38041 Grenoble, France Search for other works by this author on: GSW Google Scholar Roberto Weinberg Roberto Weinberg 3School of Earth, Atmosphere & Environment, Monash University, Clayton, 3800 VIC, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Nicolas Riel 1Department of Earth Sciences, Durham University, Science Labs, Durham DH1 3LE, UK Jonathan Mercier 2ISTerre, University Grenoble I, CNRS-IRD, 1381 rue de la Piscine, BP53, 38041 Grenoble, France Roberto Weinberg 3School of Earth, Atmosphere & Environment, Monash University, Clayton, 3800 VIC, Australia Publisher: Geological Society of America Received: 29 Jul 2015 Revision Received: 23 Oct 2015 Accepted: 01 Nov 2015 First Online: 09 Mar 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2015 Geological Society of America Geology (2016) 44 (1): 31–34. https://doi.org/10.1130/G37208.1 Article history Received: 29 Jul 2015 Revision Received: 23 Oct 2015 Accepted: 01 Nov 2015 First Online: 09 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 Nicolas Riel, Jonathan Mercier, Roberto Weinberg; Convection in a partially molten metasedimentary crust? Insights from the El Oro complex (Ecuador). Geology 2016;; 44 (1): 31–34. doi: https://doi.org/10.1130/G37208.1 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 The El Oro complex, southwestern Ecuador, is a tilted section of the metasedimentary Ecuadorian forearc, which was partially molten during Triassic time due to gabbroic magma emplacement. Pressure and maximum temperature estimates show that the metamorphic gradient during anatexis was 45 °C/km in the upper crust and 10 °C/km in the 7–8 km garnet-bearing migmatitic lower crust, controlled by biotite-breakdown melting reactions. Our petrological and geochemical studies indicate that melts produced during biotite-breakdown (5–15 vol%) were trapped and pervasively distributed in the garnet-bearing migmatite. Based on these results we carried out one-dimensional thermal modeling to characterize the heat transfer processes that led to the establishment of such a low thermal gradient during partial melting. Our results show that neither diffusive nor upward melt transfer models account for the low metamorphic gradient in the garnet-bearing migmatite. We demonstrate that in the El Oro complex, convection of the garnet-bearing migmatitic layer is the most likely heat transfer process that explains all the petrological, geochemical, and metamorphic data. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.