Le, T.X., Dirks, P.H.G.M., Sanislav, I.V., Huizenga, J.M., Cocker, H.A., and Nguyen, G.T.T. (2024) P – T conditions of metamorphic and hydrothermal events at Tick Hill Gold Deposit, Mount Isa, Queensland, Australia. Australian Journal of Earth Sciences. (In Press)

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Abstract

Tick Hill Gold Deposit is a unique gold mineralisation style in the Mary Kathleen Fold Belt in the Mount Isa Inlier. The gold at Tick Hill is generally pure without silver and was formed during two discrete metamorphic-deformation events (D1 and D3). Early gold was observed as inclusions or coarse grains hosted within D1 peak-metamorphic diopside, scapolite and hornblende from the garnet–biotite–hornblende (tschemakite)–plagioclase (andesine)–quartz assemblage. Late gold is closely associated with bismuth selenide, chlorite, albite, sericite and K-feldspar, and formed during D3. The syn-D1 garnet–plagioclase–hornblende–quartz–biotite assemblage was used to constrain the pressure and temperature (P–T) conditions of metamorphism and mineralisation using the garnet–plagioclase–hornblende–quartz barometer and the hornblende–plagioclase, garnet–biotite and garnet–hornblende thermometers. The results show that peak metamorphism at Tick Hill reached P–T conditions of 6.0–7.6 kbar and 720–760 °C. These P–T conditions together with gneissic and migmatisation textures recorded in different rock types at the Tick Hill area indicate that the peak metamorphism preserved in the area occurred at the amphibolite–granulite facies, compared with the amphibolite facies at the southern Mary Kathleen and Eastern Fold Belt. The D3 chlorite, which formed during stage 2 to stage 4 mineralisation events, displays a wide range of compositions reflecting a gradual retrograde temperature change from ∼380 °C to ∼130 °C. The pressures during D3 could not be reliably determined, but the presence of various Bi-selenides suggests that towards the waning stages of D3, the rocks may have been exhumed to a pressure less than 1 kbar.

Item ID:	82478
Item Type:	Article (Research - C1)
ISSN:	1440-0952
Copyright Information:	© 2024 the Author(s). Published by Informa UK limited, trading as taylor & francis Group. This is an open Access article distributed under the terms of the Creative Commons Attribution-noncommercial-noDerivatives license (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.
Date Deposited:	04 Apr 2024 02:00
FoR Codes:	37 EARTH SCIENCES > 3705 Geology > 370503 Igneous and metamorphic petrology @ 60% 37 EARTH SCIENCES > 3705 Geology > 370508 Resource geoscience @ 30% 37 EARTH SCIENCES > 3703 Geochemistry > 370302 Inorganic geochemistry @ 10%
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