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Invisible gold in arsenian pyrite and arsenopyrite from a multistage Archaean gold deposit: Sunrise Dam, Eastern Goldfields Province, Western Australia
Citation
Sung, YH and Brugger, J and Ciobanu, CL and Pring, A and Skinner, W and Danyushevsky, LV and Nugus, M, Invisible gold in arsenian pyrite and arsenopyrite from a multistage Archaean gold deposit: Sunrise Dam, Eastern Goldfields Province, Western Australia, Mineralium Deposita: International Journal of Geology, Mineralogy, and Geochemistry of Mineral Deposits, 44, (7) pp. 765-791. ISSN 0026-4598 (2009) [Refereed Article]
DOI: doi:10.1007/s00126-009-0244-4
Abstract
The Sunrise Dam gold mine (11.1 Moz Au) is
the largest deposit in the Archaean Laverton Greenstone
Belt (Eastern Goldfields Province, Yilgarn Craton, Western
Australia). The deposit is characterized by multiple events
of fluid flow leading to repeated alteration and mineralization
next to a major crustal-scale structure. The Au content
of arsenian pyrite and arsenopyrite from four mineralizing
stages (D1, D3, D4a, and D4b) and from different structural
and lithostratigraphic environments was measured using in
situ laser ablation inductively coupled plasma mass spectrometry.
Pyrite contains up to 3,067 ppm Au (n=224),
whereas arsenopyrite contains up to 5,767 ppm (n=19).
Gold in arsenopyrite (D4a stage) was coprecipitated and
remained as ※invisible gold§ (nanoparticles and/or latticebound)
during subsequent deformation events. In contrast,
gold in pyrite is present not only as ※invisible gold§ but
also as micrometer-size inclusions of native gold, electrum,
and Au(Ag)每tellurides. Pristine D1 and D3 arsenian pyrite
contains relatively low Au concentrations (≒26 ppm). The
highest Au concentrations occur in D4a arsenian-rich pyrite
that has recrystallized from D3 pyrite. Textures show that
this recrystallization proceeded via a coupled dissolution每
reprecipitation process, and this process may have contributed
to upgrading Au grades during D4a. In contrast, Au in
D4b pyrite shows grain-scale redistribution of ※invisible§
gold resulting in the formation of micrometer-scale inclusions
of Au minerals. The speciation of Au at Sunrise Dam
and the exceptional size of the deposit at province scale
result from multiple fluid flow and multiple Auprecipitating
mechanisms within a single plumbing system.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | gold, arsenian pyrite, Sunrise Dam, Eastern Goldfields |
| Research Division: | Earth Sciences |
| Research Group: | Geology |
| Research Field: | Resource geoscience |
| Objective Division: | Mineral Resources (Excl. Energy Resources) |
| Objective Group: | Mineral exploration |
| Objective Field: | Precious (noble) metal ore exploration |
| UTAS Author: | Danyushevsky, LV (Professor Leonid Danyushevsky) |
| ID Code: | 61798 |
| Year Published: | 2009 |
| Web of Science® Times Cited: | 193 |
| Deposited By: | Centre for Ore Deposit Research - CODES CoE |
| Deposited On: | 2010-03-05 |
| Last Modified: | 2010-04-14 |
| Downloads: | 0 |
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