Roasting the mantle: Slab melting and the genesis of major Au and Au-rich Cu deposits

Abstract

Research Article| October 01, 2002 Roasting the mantle: Slab melting and the genesis of major Au and Au-rich Cu deposits James E. Mungall James E. Mungall 1Department of Geology, University of Toronto, 22 Russell Street, Toronto, Ontario M5S 3B1, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information James E. Mungall 1Department of Geology, University of Toronto, 22 Russell Street, Toronto, Ontario M5S 3B1, Canada Publisher: Geological Society of America Received: 02 Apr 2002 Revision Received: 20 Jun 2002 Accepted: 25 Jun 2002 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (10): 915–918. https://doi.org/10.1130/0091-7613(2002)030<0915:RTMSMA>2.0.CO;2 Article history Received: 02 Apr 2002 Revision Received: 20 Jun 2002 Accepted: 25 Jun 2002 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation James E. Mungall; Roasting the mantle: Slab melting and the genesis of major Au and Au-rich Cu deposits. Geology 2002;; 30 (10): 915–918. doi: https://doi.org/10.1130/0091-7613(2002)030<0915:RTMSMA>2.0.CO;2 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 generation of large deposits of Au and Cu in suprasubduction-zone settings depends upon a combination of factors, including availability of the chalcophile elements to arc magmas in their mantle source regions, and the operation of suitable hydrothermal systems in the upper crust where the deposits eventually form. The removal of chalcophile elements from the mantle wedge into arc magmas can only occur if sulfide is absent from the melted source rock, requiring oxidation of the mantle wedge to values of log fO2 > FMQ + 2, where fO2 is oxygen fugacity and FMQ is the fayalite-magnetite-quartz oxygen buffer. The only agent capable of effecting this change is ferric iron, carried in solution by slab-derived partial melts or supercritical fluids. Arc magmas with high potential to generate Au and Cu deposits will have certain geochemical characteristics; they will have fO2 more than two log units above FMQ and they will have either adakitic, sodic-alkaline, or potassic-ultrapotassic affinities. Favorable tectonic settings include subduction of very young lithosphere or very slow or oblique convergence, flat subduction, and the cessation of subduction. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.