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Diagenetic pyrite as a source for metals in orogenic gold deposits, Otago Schist, New Zealand
Citation
Large, R and Thomas, H and Craw, D and Henne, A and Henderson, S, Diagenetic pyrite as a source for metals in orogenic gold deposits, Otago Schist, New Zealand, New Zealand Journal of Geology and Geophysics, 55, (2) pp. 137-149. ISSN 0028-8306 (2012) [Refereed Article]
Copyright Statement
Copyright 2012 The Royal Society of New Zealand
DOI: doi:10.1080/00288306.2012.682282
Abstract
Framboidal diagenetic pyrite occurs in low-grade turbidites on the northeast margin of the Otago Schist. Laser ablation inductively coupled plasma mass spectrometry (ICP-MS) analyses of these framboids show that the main metals present, in addition to Fe, are As, Pb, Zn, Te, Ag and Mo; Au is present at between 0.5 and 2 ppm. Minor Au and As anomalies also occur sporadically in the turbidite matrix. Porphyroblastic pyrite at the nearby Macraes mine contains micron-scale native gold and solid solution gold up to 30 ppm. These pyrite porphyroblasts are also enriched in As, W, Ni, Co and Bi. Lead, Zn, Te and Mo contents are distinctly lower than in the low-grade framboids. These results show that low-grade turbidites were a fertile source for Au and As for orogenic gold deposits such as Macraes. The pyrite to pyrrhotite transition, which occurred mainly under greenschist faciès conditions, was probably the most effective As and Au mobilisation reaction during Mesozoic metamorphism. © 2012 The Royal Society of New Zealand.
Item Details
Item Type: | Refereed Article |
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Research Division: | Earth Sciences |
Research Group: | Geochemistry |
Research Field: | Exploration geochemistry |
Objective Division: | Mineral Resources (Excl. Energy Resources) |
Objective Group: | Mineral exploration |
Objective Field: | Precious (noble) metal ore exploration |
UTAS Author: | Large, R (Professor Ross Large) |
UTAS Author: | Thomas, H (Dr Helen Thomas) |
ID Code: | 81408 |
Year Published: | 2012 |
Funding Support: | Australian Research Council (CE0561595) |
Web of Science® Times Cited: | 63 |
Deposited By: | Centre for Ore Deposit Research - CODES CoE |
Deposited On: | 2012-12-05 |
Last Modified: | 2013-05-27 |
Downloads: | 5 View Download Statistics |
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