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Trace element heterogeneity in molybdenite fingerprints stages of mineralization
Citation
Ciobanu, CL and Cook, NJ and Kelson, CR and Guerin, R and Kalleske, N and Danyushevsky, L, Trace element heterogeneity in molybdenite fingerprints stages of mineralization, Chemical Geology, 347 pp. 175-189. ISSN 0009-2541 (2013) [Refereed Article]
Copyright Statement
Copyright 2013 Elsevier B.V.
DOI: doi:10.1016/j.chemgeo.2013.03.011
Abstract
Variations in molybdenite trace element chemistry represent a tool for discriminating discrete events in young magmatic-hydrothermal systems and constrain the role of granites in older greenstone belt-hosted gold systems. We show that besides Re and W (typical lattice-bound elements), molybdenite also concentrates chalcophile elements with chalcogenide affinity such as Bi, Pb, and Te (CEs). Elements from the latter group form nano- to micron-scale inclusions which also attract Au and Ag incorporation. High concentration of all elements is attributable to lattice-defects and coherent intergrowths between molybdenite and CE-minerals rather than polytypism. If both groups are used, trace element patterns are useful for interpreting superimposed ore-forming processes. We test the validity of this hypothesis by carrying out Laser-Ablation Inductively-Coupled Mass Spectroscopy spot analysis and element mapping on high-Re molybdenite from the Tertiary Au deposit at Hilltop (NV, USA) and the Archean Boddington Cu-Au deposit (Western Australia). Whereas W and CEs are affected by both deformation and interaction with subsequent fluids, Re is only affected by the latter. An epithermal overprint at Hilltop, recorded in a grain with a CE-rich halo surrounding a core with Re-W oscillatory zoning, upgrades Re content and is also traceable by measurable Au. At Boddington, granite-derived fluids dilute Re in precursor molybdenite, but both granite and orogenic deformation assist CE-mineral coarsening and Au release.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | Molybdenite Laser-Ablation Inductively-Coupled Mass Spectroscopy Element mapping Bismuth Gold |
| Research Division: | Earth Sciences |
| Research Group: | Geology |
| Research Field: | Resource geoscience |
| Objective Division: | Mineral Resources (Excl. Energy Resources) |
| Objective Group: | Mineral exploration |
| Objective Field: | Mineral exploration not elsewhere classified |
| UTAS Author: | Danyushevsky, L (Professor Leonid Danyushevsky) |
| ID Code: | 87885 |
| Year Published: | 2013 |
| Web of Science® Times Cited: | 60 |
| Deposited By: | Centre for Ore Deposit Research - CODES CoE |
| Deposited On: | 2013-12-14 |
| Last Modified: | 2014-05-23 |
| Downloads: | 0 |
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