Lead Isotope Geochemistry of Shales from the Wolverine Volcanogenic Massive Sulfide Deposit, Yukon: Implications for Pb Isotope Vectoring in Exhalative Ore Systems

Research Article| February 01, 2019 Lead Isotope Geochemistry of Shales from the Wolverine Volcanogenic Massive Sulfide Deposit, Yukon: Implications for Pb Isotope Vectoring in Exhalative Ore Systems Stephen J. Piercey; Stephen J. Piercey 1Department of Earth Sciences, Memorial University, St. John’s, Newfoundland and Labrador A1B 3X5, Canada †Corresponding author: e-mail, spiercey@mun.ca Search for other works by this author on: GSW Google Scholar Balz S. Kamber Balz S. Kamber 2Irish Centre for Research in Applied Geosciences (iCRAG), Department of Geology, Trinity College Dublin, Dublin 2, D02 PN40, Ireland ☼Current address: School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland 4000, Australia. Search for other works by this author on: GSW Google Scholar Author and Article Information Stephen J. Piercey 1Department of Earth Sciences, Memorial University, St. John’s, Newfoundland and Labrador A1B 3X5, Canada Balz S. Kamber 2Irish Centre for Research in Applied Geosciences (iCRAG), Department of Geology, Trinity College Dublin, Dublin 2, D02 PN40, Ireland †Corresponding author: e-mail, spiercey@mun.ca ☼Current address: School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland 4000, Australia. Publisher: Society of Economic Geologists Accepted: 16 Dec 2018 First Online: 28 Feb 2019 Online Issn: 1554-0774 Print Issn: 0361-0128 © 2019 Economic GeologyEconomic Geology Economic Geology (2019) 114 (1): 47–66. https://doi.org/10.5382/econgeo.2019.4619 Article history Accepted: 16 Dec 2018 First Online: 28 Feb 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Stephen J. Piercey, Balz S. Kamber; Lead Isotope Geochemistry of Shales from the Wolverine Volcanogenic Massive Sulfide Deposit, Yukon: Implications for Pb Isotope Vectoring in Exhalative Ore Systems. Economic Geology 2019;; 114 (1): 47–66. doi: https://doi.org/10.5382/econgeo.2019.4619 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 Combined whole-rock lead isotope and high-precision trace element data are reported for shales from the Wolverine deposit and surrounding prospects (e.g., Puck, Fisher, Sable) to elucidate the source of Pb in the shales and their potential utility as an exploration vector. Shales exhibit distinct variations in time-integrated U/Th/Pb evolution with proximity to mineralization. Distal samples resemble the local crustal Pb isotope composition of the northern Cordilleran continental crust (i.e., shale curve). More proximal samples exhibit evidence for hydrothermal activity, but were not significantly mineralized. They have very high U/Th and U/Pb and anomalous present-day 206Pb/204Pb (>20) coincident with elevated Y/Ho, Zr/Hf, and carbonate alteration. These signatures were derived from oxygenated seawater and imprinted on the shales by oxygenated, CO2-rich hydrothermal fluids that contained uranyl carbonate ions (e.g., UO2(CO3)34−⁠). It is envisioned that this was due to shallow-level (within 50 m of the seafloor), near-vent ingress of oxygenated seawater associated with hydrothermal venting. A third population of samples is most proximal to mineralization. These, too, have trace element signatures (i.e., high Y/Ho, Zr/Hf, CO2-U enrichment) inherited from seawater, but they do not exhibit anomalous present-day 206Pb/204Pb, being more juvenile in 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb. This isotope composition coincides with enrichments in Pb, Zn, Cu, Tl, Sb, W, and Sn (±Cu, Mo). The Pb enrichment associated with mineralization effectively buffered these samples from appreciable Pb isotope evolution, despite overprinting by uranyl carbonate. The juvenile Pb associated with the shales proximal to mineralization argues for deep-penetrative circulation of hydrothermal fluids and leaching of Pb from mafic igneous rocks at depth and/or influence from juvenile magmas at depth (i.e., magmatic fluids). Both of these processes were likely critical for the genesis of mineralization at Wolverine.This study illustrates the utility of quadrupole inductively coupled plasma-mass spectrometry (ICP-MS) for providing sufficiently precise and accurate Pb isotope determinations for district-scale metallogenic evaluations. Furthermore, the coupling of solution ICP-MS Pb isotopes with high-precision trace element geochemistry from the same digest provides a powerful tool for regional exploration studies for hydrothermal mineralization in shale basins. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.