Elaine Dorothy Cu-Au (REE-U) skarn deposit

Sha, P., Spandler, C., and Chang, Z. (2015) Elaine Dorothy Cu-Au (REE-U) skarn deposit. In: Proceedings of PACRIM 2015, pp. 445-449. From: PACRIM 2015 Congress, 18-21 March 2015, Hong Kong, China.

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Abstract

The Elaine Dorothy Cu-Au (REE-V) skarn deposit in the Mt Isa Inlier, Queensland, Australia is characterised by extensive metamorphic calc-silicate hornfels long before hydrothermal skarn and complicated deformation history. The deposit is hosted by the Corella Formation (1780-1740 Ma) and exhibits two phases of skarn formation in the study area - banded finegrained diopsidic hornfels (phase 1) and coarse-grain pyroxene skarn (phase 2). Phase 1 skarn is predeformation and is interpreted to have been caused by the 1743-1734 Ma Burstall Magmatic Suites, whereas the coarse-grained pyroxene skarn (phase 2 skarn) postdates the deformation and peak metamorphism events. Phase 2 skarn consists of prograde pyroxene, less garnet and titanite, retrograde epidote, REE-allanite, amphibole, biotite, and later sulfides, carbonate, quartz, anhydrite and chlorite. It hosts most of the copper mineralisation, with the REE elements occurring mostly in allanite. Titanite coexisting with allanite and Cu-Fe sulfides in Phase 2 skarn has been dated by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) at 1524 ± 9 Ma (207 Pb/206 Pb). The ages are similar to Williams-Naraku Batholiths, which outcrop approximately 40 km to the east in the Eastern Fold Belt. In Elaine Dorothy, the isotopic compositions for calcite cluster around 12.2%0 δ180 and -3.7%0 l)13C. It probably resulted from a mixing processes between marine sourced carbon-oxygen (ca 20%0 δ180 and -0.5%0 δ13C) and other distinct geochemical reservoirs, eg magmatic c-o. These features indicate that Phase 2 skarn and Cu-Au (REE-V) mineralisation may be related to unexposed intrusions at deeper levels.

Item ID: 38255
Item Type: Conference Item (Research - E1)
ISBN: 978-1-925100-25-9
Funders: James Cook University, Chinalco Yunnan Copper, Australian Research Council (ARC)
Date Deposited: 16 Jun 2015 04:07
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040307 Ore Deposit Petrology @ 100%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840102 Copper Ore Exploration @ 60%
84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840105 Precious (Noble) Metal Ore Exploration @ 40%
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