Mafic dikes displacing Witwatersrand gold reefs: Evidence against metamorphic-hydrothermal ore formation

Research Article| July 01, 2009 Mafic dikes displacing Witwatersrand gold reefs: Evidence against metamorphic-hydrothermal ore formation Dimitri L. Meier; Dimitri L. Meier 1ETH Zurich, Isotope Geochemistry and Mineral Resources, Department of Earth Sciences, Clausiusstrasse 25, 8092 Zurich, Switzerland Search for other works by this author on: GSW Google Scholar Christoph A. Heinrich; Christoph A. Heinrich 1ETH Zurich, Isotope Geochemistry and Mineral Resources, Department of Earth Sciences, Clausiusstrasse 25, 8092 Zurich, Switzerland Search for other works by this author on: GSW Google Scholar Mark A. Watts Mark A. Watts 2AngloGold Ashanti Ltd., Siguiri Mine, Guinea Search for other works by this author on: GSW Google Scholar Geology (2009) 37 (7): 607–610. https://doi.org/10.1130/G25657A.1 Article history received: 10 Nov 2008 rev-recd: 22 Feb 2009 accepted: 23 Feb 2009 first online: 02 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 Dimitri L. Meier, Christoph A. Heinrich, Mark A. Watts; Mafic dikes displacing Witwatersrand gold reefs: Evidence against metamorphic-hydrothermal ore formation. Geology 2009;; 37 (7): 607–610. doi: https://doi.org/10.1130/G25657A.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 process responsible for the gold mineralization in the Witwatersrand Basin, South Africa, remains controversial; the debate is between a detrital placer enrichment in laterally extensive conglomerate layers, and hydrothermal introduction by metamorphic fluids long after sedimentation. While textural and geochronological data may be ambiguous, a first-order geological observation severely delimits the mechanism and timing of gold emplacement. The individual gold reefs are cut and displaced by numerous mafic dikes, which, based on geochemical data presented here, are feeders to flood basalts immediately overlying the Witwatersrand. The displacements preclude fracture-controlled fluid focusing over tens of kilometers along a single conglomerate horizon during or after regional metamorphism. Instead, basin-scale gold enrichment occurred during sedimentation or early diagenesis, well before local redistribution by metamorphic fluids. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.