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Eruptive history, geochronology, and magmatic evolution of the Puyehue-Cordon Caulle volcanic complex, Chile

2008; Geological Society of America; Volume: 120; Issue: 5-6 Linguagem: Inglês

10.1130/b26276.1

1943-2674

Brad S. Singer, Brian R. Jicha, Margaret Harper, José A. Naranjo, Luis E. Lara, H. Moreno-Roa,

High-pressure geophysics and materials

Research Article| May 01, 2008 Eruptive history, geochronology, and magmatic evolution of the Puyehue-Cordón Caulle volcanic complex, Chile Brad S. Singer; Brad S. Singer † * 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA †E-mail:bsinger@geology.wisc.edu Search for other works by this author on: GSW Google Scholar Brian R. Jicha; Brian R. Jicha ‡ 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA ‡E-mail:bjicha@geology.wisc.edu Search for other works by this author on: GSW Google Scholar Melissa A. Harper; Melissa A. Harper 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Search for other works by this author on: GSW Google Scholar José Antonio Naranjo; José Antonio Naranjo α 2Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile αE-mail:jnaranjo@sernageomin.cl Search for other works by this author on: GSW Google Scholar Luis E. Lara; Luis E. Lara ∇ 2Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile ∇E-mail:lelara@sernageomin.cl Search for other works by this author on: GSW Google Scholar Hugo Moreno-Roa Hugo Moreno-Roa § 3Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile Observatorio Volcanológico de los Andes del Sur (OVDAS), Cerro Ñielol-Sector Antenas, Temuco, Chile §E-mail:Hmoreno@sernageomin.cl Search for other works by this author on: GSW Google Scholar Author and Article Information Brad S. Singer † * 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Brian R. Jicha ‡ 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA Melissa A. Harper 1Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA José Antonio Naranjo α 2Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile Luis E. Lara ∇ 2Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile Hugo Moreno-Roa § 3Servicio Nacional de Geología y Minería (SERNAGEOMIN), Avenida Santa María, 0104 Santiago, Chile Observatorio Volcanológico de los Andes del Sur (OVDAS), Cerro Ñielol-Sector Antenas, Temuco, Chile †E-mail:bsinger@geology.wisc.edu * Corresponding author ‡E-mail:bjicha@geology.wisc.edu αE-mail:jnaranjo@sernageomin.cl ∇E-mail:lelara@sernageomin.cl §E-mail:Hmoreno@sernageomin.cl Publisher: Geological Society of America Received: 19 Jun 2007 Revision Received: 04 Oct 2007 Accepted: 09 Oct 2007 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2008 Geological Society of America GSA Bulletin (2008) 120 (5-6): 599–618. https://doi.org/10.1130/B26276.1 Article history Received: 19 Jun 2007 Revision Received: 04 Oct 2007 Accepted: 09 Oct 2007 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Brad S. Singer, Brian R. Jicha, Melissa A. Harper, José Antonio Naranjo, Luis E. Lara, Hugo Moreno-Roa; Eruptive history, geochronology, and magmatic evolution of the Puyehue-Cordón Caulle volcanic complex, Chile. GSA Bulletin 2008;; 120 (5-6): 599–618. doi: https://doi.org/10.1130/B26276.1 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 Forty-three 40Ar/39Ar age determinations of lava flows, domes, ignimbrites, and dikes, plus 14C dates from seven distal tephra layers, combined with stratigraphy, geochemistry, and Sr and Th isotope data, establish an eruptive chronology for the Puyehue-Cordón Caulle volcanic complex at 40.5° S in the Andean southern volcanic zone (SVZ). The complex preserves ~131 km3 of lava and tephra that erupted from numerous vents widely separated in time and space. Approximately 80% of the total volume consists of basaltic to andesitic lava that formed two broad shield volcanoes between 314 and 70 ka. The modern Puyehue stratovolcano was built on the southerly shield during the past 69 k.y. following a hiatus of 25 k.y. Puyehue has erupted ~15 km3 of basaltic to rhyolitic magma that spans the entire compositional range found in the southern SVZ and evolved via at least six phases including: (1) basaltic andesitic to dacitic lavas between 69 and 32 ka, (2) a shift to bimodal magma compositions that is first expressed by a rhyodacite mingled with inclusions of MgO-rich basaltic andesite at 34 ka, (3) dacitic to rhyolitic flows and domes from 19 to 12 ka, (4) basaltic to basaltic andesitic flows between 15 and 12 ka, (5) subsequent rhyolitic dome growth in several effusive and explosive stages between 7 and 5 ka, followed by (6) a powerful series of phreatomagmatic and sub-Plinian eruptions at ca. 1.1 ka that obliterated the preceding rhyolite domes and formed the present 2.5-km-diameter, 280-m-deep summit crater. Along the Cordón Caulle fissure zone, ~5 km3 of rhyodacitic to rhyolitic lavas, domes, and cones have formed during the past ~16.5 k.y., including explosive and effusive eruptions in 1921–1922 and 1960.Eruptive rates were nonuniform over time, with background growth at 0.04 km3/k.y. or less, punctuated by spurts at up to 0.90 km3/k.y. The time-averaged rate, 0.42 km3/k.y., is nearly double that at the Tatara-San Pedro complex 500 km to the north during the past 300 k.y. These findings indicate that within a single arc the magmatic and eruptive fluxes at individual frontal volcanoes can be highly variable. The last three stratocone-building events on Puyehue began during periods of deglaciation, suggesting a relationship between unloading of ice and ease of magma ascent. Puyehue basalt exhibits subtle changes in 238U-230Th, 87Sr/86Sr, and trace element composition over time that signal shifts in the composition and degree of melting of the mantle wedge, or the extent to which basalt was modified by assimilation of heterogeneous crustal melts. The complex has become exceptionally bimodal and more explosive over time with recent rhyolites evolving by extreme crystal fractionation of mafic magma and lesser volumes of andesite and dacite created via mixing of rhyolite and basalt. Despite the high flux of basalt during the past 300 k.y., no large silicic magma reservoir formed in the upper crust. Instead, 238U-230Th data favor rapid ascent of several small bodies of basaltic and silicic magma from the lower crust, promoted perhaps by conduits that reflect strike-slip faulting beneath the complex. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.