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Isotopic shifts in the Cenozoic Andean arc of central Chile: Records of an evolving basement throughout cordilleran arc mountain building

2013; Geological Society of America; Volume: 41; Issue: 8 Linguagem: Inglês

10.1130/g34178.1

1943-2682

Marcia Muñoz, Marcelo Farías, Reynaldo Charrier, C. Mark Fanning, Mireille Polvé, Katja Deckart,

High-pressure geophysics and materials

Research Article| August 01, 2013 Isotopic shifts in the Cenozoic Andean arc of central Chile: Records of an evolving basement throughout cordilleran arc mountain building Marcia Muñoz; Marcia Muñoz * 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile *E-mails: marmunoz@ing.uchile.cl; Mark.Fanning@anu.edu.au; polve@lmtg.obs-mip.fr. Search for other works by this author on: GSW Google Scholar Marcelo Farías; Marcelo Farías 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile Search for other works by this author on: GSW Google Scholar Reynaldo Charrier; Reynaldo Charrier 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile2Escuela de Ciencias de la Tierra, Universidad Andres Bello, Campus República, Av. República 237, Santiago, Chile Search for other works by this author on: GSW Google Scholar C. Mark Fanning; C. Mark Fanning * 3Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia *E-mails: marmunoz@ing.uchile.cl; Mark.Fanning@anu.edu.au; polve@lmtg.obs-mip.fr. Search for other works by this author on: GSW Google Scholar Mireille Polvé; Mireille Polvé * 4LMTG, Université de Toulouse CNRS, IRD, OMP, Av. Edouard Belin, 31400 Toulouse, France *E-mails: marmunoz@ing.uchile.cl; Mark.Fanning@anu.edu.au; polve@lmtg.obs-mip.fr. Search for other works by this author on: GSW Google Scholar Katja Deckart Katja Deckart 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile Search for other works by this author on: GSW Google Scholar Author and Article Information Marcia Muñoz * 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile Marcelo Farías 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile Reynaldo Charrier 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile2Escuela de Ciencias de la Tierra, Universidad Andres Bello, Campus República, Av. República 237, Santiago, Chile C. Mark Fanning * 3Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Mireille Polvé * 4LMTG, Université de Toulouse CNRS, IRD, OMP, Av. Edouard Belin, 31400 Toulouse, France Katja Deckart 1Departamento de Geología, FCFM, Universidad de Chile, Casilla 13518, Correo 21, Santiago, Chile *E-mails: marmunoz@ing.uchile.cl; Mark.Fanning@anu.edu.au; polve@lmtg.obs-mip.fr. Publisher: Geological Society of America Received: 27 Oct 2012 Revision Received: 01 Apr 2013 Accepted: 11 Apr 2013 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (8): 931–934. https://doi.org/10.1130/G34178.1 Article history Received: 27 Oct 2012 Revision Received: 01 Apr 2013 Accepted: 11 Apr 2013 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Marcia Muñoz, Marcelo Farías, Reynaldo Charrier, C. Mark Fanning, Mireille Polvé, Katja Deckart; Isotopic shifts in the Cenozoic Andean arc of central Chile: Records of an evolving basement throughout cordilleran arc mountain building. Geology 2013;; 41 (8): 931–934. doi: https://doi.org/10.1130/G34178.1 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 analysis of new and published Hf and Nd isotopic data of late Cenozoic Andean arc igneous rocks from central Chile, coupled with our improved knowledge of orogenic processes in the region, reveals a tight link between major magmatic isotopic shifts and different Andean basement domains and timing of the main uplifting event. Oligocene–Miocene magmas from the Western Principal Cordillera show a nearly constant and juvenile composition (εHfI: +5 to +10; εNdI: +2 to +7), while those from the Eastern Principal Cordillera, formed since early late Miocene, are variably more enriched (εHfI: –4 to +4; εNdI: 0 to +3). Post–4.8 Ma magmas from both belts share an enriched signature (εNdI: –2 to +2) reflecting source contamination from east to west, contrary to the eastward subduction direction, in a process that occurred toward the end of the main Andean uplifting event. This results from the deep western basement underthrusting the orogen, and thus accounts for the westward propagation of the eastern enriched isotopic signatures approximately coeval with thickening and uplifting events. The observed patterns highlight the strong control exerted by the continental lithosphere on the composition of arc magmas over deep controls from the subduction-modified asthenospheric mantle. Moreover, they dynamically represent both (1) the hybridization affecting magmas ascending from the mantle in a heterogeneous continental lithosphere, and (2) the evolution of such lithosphere resulting from the thermal weakening and mass transfer processes occurring underneath cordilleran arcs during mountain building. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.