Volcano evolution and eruptive flux on the thick crust of the Andean Central Volcanic Zone: 40Ar/39Ar constraints from Volcan Parinacota, Chile

Abstract

Research Article| March 01, 2007 Volcano evolution and eruptive flux on the thick crust of the Andean Central Volcanic Zone: 40Ar/39Ar constraints from Volcán Parinacota, Chile John M. Hora; John M. Hora 1Department of Geology and Geophysics, University of Wisconsin–Madison, 1215 W. Dayton Street, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Brad S. Singer; Brad S. Singer 1Department of Geology and Geophysics, University of Wisconsin–Madison, 1215 W. Dayton Street, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar Gerhard Wörner Gerhard Wörner 2Geowissenschaftliches Zentrum der Universität Göttingen, Abteilung Geochemie, Goldschmidtstrasse 1, 37077 Göttingen, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information John M. Hora 1Department of Geology and Geophysics, University of Wisconsin–Madison, 1215 W. Dayton Street, Madison, Wisconsin 53706, USA Brad S. Singer 1Department of Geology and Geophysics, University of Wisconsin–Madison, 1215 W. Dayton Street, Madison, Wisconsin 53706, USA Gerhard Wörner 2Geowissenschaftliches Zentrum der Universität Göttingen, Abteilung Geochemie, Goldschmidtstrasse 1, 37077 Göttingen, Germany Publisher: Geological Society of America Received: 19 Dec 2005 Revision Received: 07 Aug 2006 Accepted: 26 Sep 2006 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 GEOLOGICAL SOCIETY OF AMERICA GSA Bulletin (2007) 119 (3-4): 343–362. https://doi.org/10.1130/B25954.1 Article history Received: 19 Dec 2005 Revision Received: 07 Aug 2006 Accepted: 26 Sep 2006 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation John M. Hora, Brad S. Singer, Gerhard Wörner; Volcano evolution and eruptive flux on the thick crust of the Andean Central Volcanic Zone: 40Ar/39Ar constraints from Volcán Parinacota, Chile. GSA Bulletin 2007;; 119 (3-4): 343–362. doi: https://doi.org/10.1130/B25954.1 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 The 163 k.y. history as well as the chemical and 46 km3 volumetric evolution of Volcán Parinacota are described in detail by new mapping, stratigraphy, and 57 40Ar/39Ar ages determined from groundmass or sanidine crystals in basaltic andesitic to rhyolitic lavas. A more precise chronology of eruptions and associated eruptive volumes of this central Andean volcano, which was built upon 70-km-thick crust, provides a more complete view of how quickly volcanic edifices are built in this setting and how their magmatic systems evolve during their lifetime. Development of the complex involved initial eruption of andesitic lava flows (163–117 ka) followed by a rhyodacite dome plateau (47–40 ka) synchronous with the onset of the building of a stratocone (52–20 ka), which was later destroyed by a debris avalanche ∼3 times larger than that at Mount St. Helens in 1980. Dome plateau emplacement occurred faster and later than has previously been published, implying a compressed duration of cone building and introducing a preceding 65 k.y. hiatus. Debris avalanche timing is refined here to be older than 10 but younger than 20 ka. Rapid postcollapse rebuilding of the volcanic edifice is delineated by 16 groundmass and whole-rock 40Ar/39Ar ages, which include some of the youngest lava flows dated by this method. Increase in cone-building rate and a continued trend toward more mafic compositions following collapse imply an inter-relationship between the presence of the edifice and flux of magma from the feeding reservoir. Cone-building rates at Parinacota are similar to those at other well-dated volcanoes on thinner crust; however, the distributed basaltic volcanism prevalent in those other arcs is virtually absent both at Parinacota and elsewhere in the Central Volcanic Zone. This suggests that while the hydrous, calc-alkaline magmas that make up the central volcanoes are not significantly retarded by thick crust, primitive, dry basalts might be. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.