Problems with the placer model for Witwatersrand gold

Abstract

Research Article| November 01, 1987 Problems with the placer model for Witwatersrand gold G. Neil Phillips; G. Neil Phillips 1Department of Geology, University of Witwatersrand, Johannesburg, Wits 2050, South Africa Search for other works by this author on: GSW Google Scholar Russell E. Myers; Russell E. Myers 1Department of Geology, University of Witwatersrand, Johannesburg, Wits 2050, South Africa Search for other works by this author on: GSW Google Scholar Judy A. Palmer Judy A. Palmer 1Department of Geology, University of Witwatersrand, Johannesburg, Wits 2050, South Africa Search for other works by this author on: GSW Google Scholar Geology (1987) 15 (11): 1027–1030. https://doi.org/10.1130/0091-7613(1987)15<1027:PWTPMF>2.0.CO;2 Article history 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 G. Neil Phillips, Russell E. Myers, Judy A. Palmer; Problems with the placer model for Witwatersrand gold. Geology 1987;; 15 (11): 1027–1030. doi: https://doi.org/10.1130/0091-7613(1987)15<1027:PWTPMF>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 Problems with the placer model for genesis of the Witwatersrand gold include the lack of Fe oxides but abundance of pyrite, unusual sulfides in the reefs, detrital transport of uraninite grains, the inference of hydraulic equivalence of reef minerals, and the source of the gold itself. Other features not predicted by the current placer model are mineralization in the immediate footwall of the reefs, apparent structural control of payshoot orientations, and the basinwide chemical associations that include Au-S-Fe-As-C and U-C-Ti.The supposed total predictive capacity of the placer model is questioned here, and an alternative viewpoint is presented that emphasizes the possible importance of postburial fluids during diagenesis, deformation, and metamorphism. Chloritoid and pyrophyllite independently suggest that greenschist facies conditions (T = 350 ±50 °C) were reached in all the Witwatersrand gold mines. A fluid in equilibrium with pyrite and having potential to move gold is inferred from the mineral assemblages, but the effect of this fluid on the reefs has not yet been quantified. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.