Major and Trace Element Chemistry of Gahnite as an Exploration Guide to Broken Hill-Type Pb-Zn-Ag Mineralization in the Broken Hill Domain, New South Wales, Australia

Abstract

Research Article| June 01, 2015 Major and Trace Element Chemistry of Gahnite as an Exploration Guide to Broken Hill-Type Pb-Zn-Ag Mineralization in the Broken Hill Domain, New South Wales, Australia Joshua J. O’Brien; Joshua J. O’Brien † 1Department of Geological and Atmospheric Sciences, 253 Science I, Iowa State University, Ames, Iowa 50011-3212 †Corresponding author: e-mail, jjobrien@iastate.edu Search for other works by this author on: GSW Google Scholar Paul G. Spry; Paul G. Spry 1Department of Geological and Atmospheric Sciences, 253 Science I, Iowa State University, Ames, Iowa 50011-3212 Search for other works by this author on: GSW Google Scholar Graham S. Teale; Graham S. Teale 2Teale and Associates, P.O. Box 740, North Adelaide, South Australia 5006, Australia Search for other works by this author on: GSW Google Scholar Simon E. Jackson; Simon E. Jackson 3Natural Resources Canada, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar Dean Rogers Dean Rogers 4Perilya Limited, P.O. Box 5001, Broken Hill, New South Wales 2880, Australia Search for other works by this author on: GSW Google Scholar Economic Geology (2015) 110 (4): 1027–1057. https://doi.org/10.2113/econgeo.110.4.1027 Article history received: 02 Jun 2014 accepted: 02 Nov 2014 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 Joshua J. O’Brien, Paul G. Spry, Graham S. Teale, Simon E. Jackson, Dean Rogers; Major and Trace Element Chemistry of Gahnite as an Exploration Guide to Broken Hill-Type Pb-Zn-Ag Mineralization in the Broken Hill Domain, New South Wales, Australia. Economic Geology 2015;; 110 (4): 1027–1057. doi: https://doi.org/10.2113/econgeo.110.4.1027 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 SocietyEconomic Geology Search Advanced Search Abstract Gahnite-bearing rocks are common throughout the Proterozoic Broken Hill domain, New South Wales, Australia, where they are spatially associated with Broken Hill-type Pb-Zn-Ag mineralization, including the supergiant Broken Hill deposit. In the past, such rocks have been utilized as exploration guides to ores of this type, but their presence has had mixed success in discovering new occurrences of sulfide mineralization. Major element chemistry of gahnite has previously been used to define a compositional range associated with metamorphosed massive sulfides deposits, including Broken Hill-type deposits, but it fails to distinguish sulfide-rich from sulfide-poor occurrences. Major and trace element data from LA-ICP-MS and electron microprobe analyses were obtained for gahnite from twelve Broken Hill-type deposits to determine whether or not gahnite chemistry may be used to distinguish prospective exploration targets from nonprospective occurrences. Major and trace element data were discriminated using a principal component analysis, and in a bivariate plot of Zn/Fe versus Ni + Cr + V to distinguish gahnite associated with the Broken Hill deposit from that associated with sulfide-poor lode pegmatite, and sillimanite gneiss. Bivariate plots of Zn/Fe versus trace element contents (e.g., Ga, Co, Mn, Co, Ni, V, Cd) suggest gahnite from the Broken Hill deposit has a relatively restricted compositional range that overlaps with some minor Broken Hill-type occurrences. Based on the ore grade (wt % Pb + Zn) of rocks hosting gahnite at each locality, gahnite in the highest grade mineralization from minor Broken Hill-type deposits possess compositions that plot within the field for gahnite from the Broken Hill deposit, which suggests that major and trace element chemistry (e.g., Zn/Fe = 2–4 vs. Co = 10–110 ppm, Ga = 110–400 ppm, Mn = 500–2,250 ppm; and Co = 25–100 ppm vs. Ga = 125–375 ppm) may be used as an exploration guide to high-grade ore. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.