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Iron-rich melts, magmatic magnetite, and superheated hydrothermal systems: The El Laco deposit, Chile

2016; Geological Society of America; Volume: 44; Issue: 6 Linguagem: Inglês

10.1130/g37705.1

1943-2682

Fernando Tornos, Francisco Velasco, John M. Hanchar,

Geomagnetism and Paleomagnetism Studies

Research Article| June 01, 2016 Iron-rich melts, magmatic magnetite, and superheated hydrothermal systems: The El Laco deposit, Chile Fernando Tornos; Fernando Tornos * 1Centro de Astrobiología (CSIC-INTA). Ctra. de Torrejón a Ajalvir, km 4.5, 28850 Torrejón de Ardoz, Madrid, Spain *E-mails: f.tornos@csic.es, francisco.velasco@ehu.es, jhanchar@mun.ca Search for other works by this author on: GSW Google Scholar Francisco Velasco; Francisco Velasco * 2Departamento de Mineralogía y Petrología, Universidad del País Vasco UPV/EHU, 48080 Bilbao, Spain *E-mails: f.tornos@csic.es, francisco.velasco@ehu.es, jhanchar@mun.ca Search for other works by this author on: GSW Google Scholar John M. Hanchar John M. Hanchar * 3Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X5, Canada *E-mails: f.tornos@csic.es, francisco.velasco@ehu.es, jhanchar@mun.ca Search for other works by this author on: GSW Google Scholar Author and Article Information Fernando Tornos * 1Centro de Astrobiología (CSIC-INTA). Ctra. de Torrejón a Ajalvir, km 4.5, 28850 Torrejón de Ardoz, Madrid, Spain Francisco Velasco * 2Departamento de Mineralogía y Petrología, Universidad del País Vasco UPV/EHU, 48080 Bilbao, Spain John M. Hanchar * 3Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1B 3X5, Canada *E-mails: f.tornos@csic.es, francisco.velasco@ehu.es, jhanchar@mun.ca Publisher: Geological Society of America Received: 20 Jan 2016 Revision Received: 06 Apr 2016 Accepted: 07 Apr 2016 First Online: 09 Mar 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2016 Geological Society of America Geology (2016) 44 (6): 427–430. https://doi.org/10.1130/G37705.1 Article history Received: 20 Jan 2016 Revision Received: 06 Apr 2016 Accepted: 07 Apr 2016 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Fernando Tornos, Francisco Velasco, John M. Hanchar; Iron-rich melts, magmatic magnetite, and superheated hydrothermal systems: The El Laco deposit, Chile. Geology 2016;; 44 (6): 427–430. doi: https://doi.org/10.1130/G37705.1 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 We propose an integrated model that explains the magmatic and hydrothermal features of the unique El Laco iron deposit that is located in a Pliocene–Pleistocene volcano of the Chilean Andes. (Sub)volcanic crystallization of an iron-rich melt as massive magnetite promoted the exsolution of a small volume of a hydrosaline melt and of large amounts of vapor that led to the formation of an alkali-calcic hydrothermal assemblage replacing the host andesite; this assemblage is capped and overprinted by a large zone of acid-sulfate steam-heated alteration forming as a whole a protracted shallow-level magmatic-hydrothermal system. Oxygen isotopic data for the massive magnetite (δ18O: 4.3‰–5.0‰) and the alkali-calcic altered rock (diopside δ18O: 7.2‰–8.7‰; magnetite δ18O: 4.4‰–6.7‰) suggest that these rocks are genetically related to the host andesite (δ18O: 7.4‰–9.6‰). The estimated temperature of the mineral assemblage (>∼900 °C) may be the highest recorded in hydrothermal systems, is attributed to exsolution of fluids from the crystallizing iron-rich melts, and is considered unlikely to reflect the convection of surficial fluids. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.