Integration of Detrital Gold Microchemistry, Heavy Mineral Distribution, and Sediment Geochemistry to Clarify Regional Metallogeny in Glaciated Terrains: Application in the Caledonides of Southeast Ireland

Research Article| March 01, 2019 Integration of Detrital Gold Microchemistry, Heavy Mineral Distribution, and Sediment Geochemistry to Clarify Regional Metallogeny in Glaciated Terrains: Application in the Caledonides of Southeast Ireland N. R. Moles; N. R. Moles 1School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, United Kingdom †Corresponding author: e-mail, n.moles@brighton.ac.uk Search for other works by this author on: GSW Google Scholar R. J. Chapman R. J. Chapman 2Ores and Mineralization Group, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom Search for other works by this author on: GSW Google Scholar Author and Article Information N. R. Moles 1School of Environment and Technology, University of Brighton, Brighton BN2 4GJ, United Kingdom R. J. Chapman 2Ores and Mineralization Group, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom †Corresponding author: e-mail, n.moles@brighton.ac.uk Publisher: Society of Economic Geologists Accepted: 21 Dec 2018 First Online: 27 Mar 2019 Online Issn: 1554-0774 Print Issn: 0361-0128 © 2019 Economic GeologyEconomic Geology Economic Geology (2019) 114 (2): 207–232. https://doi.org/10.5382/econgeo.2019.4628 Article history Accepted: 21 Dec 2018 First Online: 27 Mar 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation N. R. Moles, R. J. Chapman; Integration of Detrital Gold Microchemistry, Heavy Mineral Distribution, and Sediment Geochemistry to Clarify Regional Metallogeny in Glaciated Terrains: Application in the Caledonides of Southeast Ireland. Economic Geology 2019;; 114 (2): 207–232. doi: https://doi.org/10.5382/econgeo.2019.4628 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 Regional exploration for rare and precious metal enrichment traditionally uses multielement geochemical analysis of the fines (<150 μm) fraction of stream sediments; however, these data can be misleading in glaciated regions with complex geology. Here, we compare the spatial distributions of data from sediment fines with distributions of heavy mineral concentrates, including detrital gold, in the same region. Gold grains are characterized according to abundance and morphology plus a microchemical signature from the combination of alloy analysis and systematic identification of mineral inclusions revealed in polished sections. These inclusions survive indefinitely and are indicative of hypogene mineralogy, whereas the metal loadings of fines may be affected by weathering or anthropogenic activity. All three approaches are mutually supportive: sediment fines analyses provide a basis for more labor-intensive targeted gold-grain studies, which in turn highlight specific gold-element associations useful for interpretation of geochemical data sets. Spatial distributions of resistate heavy mineral suites constrain the directions and extents of glacial transport, which facilitates more confident interpretations of placer-lode relationships from gold-grain studies.Characterization of 2,160 gold grains from 40 localities in the auriferous region of southeast Ireland provided a clear indication of proximity of gold to source and identified gold derived from different episodes of mineralization. A distinction is apparent between gold in the south of the region (Wexford), likely derived from widespread stratabound Au-As-Fe-S mineralization, and that in the north (Wicklow), where the historical placer mining district of the Goldmines River yielded gold with inclusions exhibiting a distinctive Pb-Bi-As association. The Goldmines River placers formed by the efficient accumulation and preservation of detrital gold derived from several discrete intravalley sources. We recommend that a combination of classic stream-sediment geochemistry, heavy mineral analysis, and gold-grain studies is used more widely to provide additional insights on the location and nature of gold mineralization and regional metallogeny in regions of poor exposure and complex geology. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.