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The Altar Porphyry Cu-(Au-Mo) Deposit (Argentina): A Complex Magmatic-Hydrothermal System with Evidence of Recharge Processes

2014; Volume: 109; Issue: 3 Linguagem: Inglês

10.2113/econgeo.109.3.621

1554-0774

Laura Maydagán, Marta Franchini, Massimo Chiaradia, John H. Dilles, Roger Rey,

earthquake and tectonic studies

Research Article| May 01, 2014 The Altar Porphyry Cu-(Au-Mo) Deposit (Argentina): A Complex Magmatic-Hydrothermal System with Evidence of Recharge Processes* Laura Maydagán; Laura Maydagán † 1Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Avenida Rivadavia 1917, Ciudad Autónoma de Buenos Aires, Argentina2Departamento de Geología y Petróleo, Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén, Argentina3Departamento de Geología, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina †Corresponding author: e-mail, lauramaydagan@yahoo.com.ar Search for other works by this author on: GSW Google Scholar Marta Franchini; Marta Franchini 1Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Avenida Rivadavia 1917, Ciudad Autónoma de Buenos Aires, Argentina2Departamento de Geología y Petróleo, Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén, Argentina Search for other works by this author on: GSW Google Scholar Massimo Chiaradia; Massimo Chiaradia 4Department of Mineralogy, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland Search for other works by this author on: GSW Google Scholar John Dilles; John Dilles 5College of Earth, Ocean and Atmospheric Sciences, Oregon State University, 104 CEOAS Admin Bldg, Corvallis, Oregon 97331 Search for other works by this author on: GSW Google Scholar Roger Rey Roger Rey 6Peregrine Metals Ltd. Santa Fe (Oeste) 117, Piso 5, Edificio Derby, Ciudad San Juan, Argentina Search for other works by this author on: GSW Google Scholar Author and Article Information Laura Maydagán † 1Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Avenida Rivadavia 1917, Ciudad Autónoma de Buenos Aires, Argentina2Departamento de Geología y Petróleo, Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén, Argentina3Departamento de Geología, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina Marta Franchini 1Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Avenida Rivadavia 1917, Ciudad Autónoma de Buenos Aires, Argentina2Departamento de Geología y Petróleo, Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén, Argentina Massimo Chiaradia 4Department of Mineralogy, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland John Dilles 5College of Earth, Ocean and Atmospheric Sciences, Oregon State University, 104 CEOAS Admin Bldg, Corvallis, Oregon 97331 Roger Rey 6Peregrine Metals Ltd. Santa Fe (Oeste) 117, Piso 5, Edificio Derby, Ciudad San Juan, Argentina †Corresponding author: e-mail, lauramaydagan@yahoo.com.ar Publisher: Society of Economic Geologists Received: 19 Jun 2012 Accepted: 26 Jun 2013 First Online: 09 Mar 2017 Online ISSN: 1554-0774 Print ISSN: 0361-0128 © 2014 Society of Economic Geologists. Economic Geology (2014) 109 (3): 621–641. https://doi.org/10.2113/econgeo.109.3.621 Article history Received: 19 Jun 2012 Accepted: 26 Jun 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 Laura Maydagán, Marta Franchini, Massimo Chiaradia, John Dilles, Roger Rey; The Altar Porphyry Cu-(Au-Mo) Deposit (Argentina): A Complex Magmatic-Hydrothermal System with Evidence of Recharge Processes. Economic Geology 2014;; 109 (3): 621–641. doi: https://doi.org/10.2113/econgeo.109.3.621 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 SocietyEconomic Geology Search Advanced Search Abstract Altar (31° 29′ S, 70° 28′ W) is a large porphyry Cu-(Au-Mo) deposit with associated epithermal Au-(Ag-Cu) veins located in the Cordillera Principal of southwest San Juan province (Argentina). Altar is a complex magmatic-hydrothermal system formed from several magmatic and hydrothermal pulses during the middle-late Miocene. New LA-ICPMS U-Pb ages in zircons from the Altar porphyries indicate four discrete events of intrusions over an extended magmatic life time of ca. 3 m.y. It comprises a premineralization porphyry (11.75 ± 0.24 Ma), three mineralized porphyries (11.62 ± 0.21 and 11.68 ± 0.27 Ma, 11.13 ± 0.26 Ma, 10.35 ± 0.32 Ma) related to hydrothermal breccias, two postmineralization intrusions, and a postmineralization breccia (8.9 ± 0.4 Ma). The three mineralized porphyries (porphyries 2, 3, and 4) were emplaced within ~0.7 to 1.3 m.y.Amphibole phenocrysts from the porphyries crystallized from oxidized magmas (fO2 = NNO +1 to +2) at temperatures of 780° to 850°C and pressures between 0.9 and 1.8 kbars corresponding to depths of ~4 to 7 km. Anorthite- and Fe-rich rims in the plagioclase phenocrysts suggest that the magmatic chambers were episodically recharged by a less evolved magma. The middle-late Miocene intrusions are interpreted to have been derived from a deeper and relatively large magmatic reservoir that supplied magmas to smaller chambers located in the upper crust. The focused magmatic output to shallow levels during a period of a few million years in the Altar area has been a main requirement in the formation of this large porphyry copper deposit. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.