Magmatic-hydrothermal processes within an evolving Earth: Iron oxide-copper-gold and porphyry Cu   Mo   Au deposits

Research Article| July 01, 2013 Magmatic-hydrothermal processes within an evolving Earth: Iron oxide-copper-gold and porphyry Cu ± Mo ± Au deposits Jeremy P. Richards; Jeremy P. Richards * 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada *E-mails: Jeremy.Richards@ualberta.ca; Mumin@BrandonU.ca. Search for other works by this author on: GSW Google Scholar A. Hamid Mumin A. Hamid Mumin * 2Department of Geology, Brandon University, 270 18th Street, Brandon, Manitoba R7A 6A9, Canada *E-mails: Jeremy.Richards@ualberta.ca; Mumin@BrandonU.ca. Search for other works by this author on: GSW Google Scholar Author and Article Information Jeremy P. Richards * 1Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada A. Hamid Mumin * 2Department of Geology, Brandon University, 270 18th Street, Brandon, Manitoba R7A 6A9, Canada *E-mails: Jeremy.Richards@ualberta.ca; Mumin@BrandonU.ca. Publisher: Geological Society of America Received: 29 Nov 2012 Revision Received: 11 Feb 2013 Accepted: 14 Feb 2013 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2013 Geological Society of America Geology (2013) 41 (7): 767–770. https://doi.org/10.1130/G34275.1 Article history Received: 29 Nov 2012 Revision Received: 11 Feb 2013 Accepted: 14 Feb 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 Jeremy P. Richards, A. Hamid Mumin; Magmatic-hydrothermal processes within an evolving Earth: Iron oxide-copper-gold and porphyry Cu ± Mo ± Au deposits. Geology 2013;; 41 (7): 767–770. doi: https://doi.org/10.1130/G34275.1 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 Iron oxide-copper-gold (IOCG) deposits formed by magmatic-hydrothermal fluids (MH-IOCG) share many similarities with, but have important differences from, porphyry Cu ± Mo ± Au (porphyry) deposits: MH-IOCG deposits predominantly occur in Precambrian rocks, are Fe oxide rich, and have volumetrically extensive high-temperature alteration zones, whereas porphyry deposits occur almost exclusively in Phanerozoic rocks, are Fe sulfide rich, and have narrower high-temperature alteration zones. We propose that these deposit types are linked by common subduction-modified magmatic sources, but that secular changes in oceanic sulfate content and geothermal gradients at the end of the Precambrian caused a transition from the predominance of S-poor arc magmas and associated S-poor MH-IOCG systems, to S-rich arc magmas and associated S-rich porphyry deposits in the Phanerozoic. Phanerozoic MH-IOCG and rare Precambrian porphyry deposits are explained by local or periodic fluctuations in oceanic oxidation state and sulfate content, or remobilization of previously subduction-modified lithosphere in post-subduction tectonic settings. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.