Research Article| August 04, 2017 Backarc origin for Neoarchean ultrahigh-temperature metamorphism, eclogitization, and orogenic root growth Gregory Dumond; Gregory Dumond * 1Department of Geosciences, University of Arkansas, Fayetteville, Arkansas 72701, USA *E-mail: gdumond@uark.edu Search for other works by this author on: GSW Google Scholar Michael L. Williams; Michael L. Williams 2Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003-9297, USA Search for other works by this author on: GSW Google Scholar Julia A. Baldwin; Julia A. Baldwin 3Department of Geosciences, University of Montana, Missoula, Montana 59812-1296, USA Search for other works by this author on: GSW Google Scholar Michael J. Jercinovic Michael J. Jercinovic 2Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003-9297, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Gregory Dumond * 1Department of Geosciences, University of Arkansas, Fayetteville, Arkansas 72701, USA Michael L. Williams 2Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003-9297, USA Julia A. Baldwin 3Department of Geosciences, University of Montana, Missoula, Montana 59812-1296, USA Michael J. Jercinovic 2Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003-9297, USA *E-mail: gdumond@uark.edu Publisher: Geological Society of America Received: 20 Apr 2017 Revision Received: 05 Jul 2017 Accepted: 06 Jul 2017 First Online: 04 Aug 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2017 Geological Society of America Geology (2017) 45 (10): 943–946. https://doi.org/10.1130/G39254.1 Article history Received: 20 Apr 2017 Revision Received: 05 Jul 2017 Accepted: 06 Jul 2017 First Online: 04 Aug 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Gregory Dumond, Michael L. Williams, Julia A. Baldwin, Michael J. Jercinovic; Backarc origin for Neoarchean ultrahigh-temperature metamorphism, eclogitization, and orogenic root growth. Geology 2017;; 45 (10): 943–946. doi: https://doi.org/10.1130/G39254.1 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 Contraction of continental crust during orogeny results in elevated topography at the surface and a root at depth. Thermomechanical models suggest that root growth is enhanced by thickening of thermally softened thin lithosphere. A >400 km2 region of Archean gneiss in the Athabasca granulite terrane in the Canadian shield contains abundant mafic sills with mid-oceanic ridge basalt–like chemistry. Heat from the sills facilitated melting of supracrustal host rocks along a prograde pressure-temperature (P-T) path culminating at P > 1.4 GPa and T > 950 °C in the Neoarchean. A basalt sill, converted to eclogite near the base of the domain, exhibits positive Eu anomalies consistent with plagioclase accumulation at a shallow crustal level prior to burial. Eclogite facies metamorphism previously dated as 1.90 Ga is here revised to 2.54 Ga based on existing zircon dates from the sill and new monazite dates from the paragneiss that hosts the sill. The results suggest that upper crustal materials were thermally softened in a backarc setting prior to burial to lower crustal levels during orogenic root growth. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
