129977 - Linking gold mineralization to regional-scale drivers of mineral systems.pdf (9.21 MB)
Linking gold mineralization to regional-scale drivers of mineral systems using in situ U-Pb geochronology and pyrite LA-ICP-MS element mapping
journal contribution
posted on 2023-05-19, 23:35 authored by Fielding, IOH, Johnson, SP, Sebastien MeffreSebastien Meffre, Zi, J, Sheppard, S, Ross LargeRoss Large, Rasmussen, BProterozoic orogens commonly host a range of hydrothermal ores that form in diverse tectonic settings at different times. However, the link between mineralization and the regional-scale tectonothermal evolution of orogens is usually not well understood, especially in areas subject to multiple hydrothermal events. Regional-scale drivers for mineral systems vary between the different classes of hydrothermal ore, but all involve an energy source and a fluid pathway to focus mineralizing fluids into the upper crust. The Mount Olympus gold deposit in the Proterozoic Capricorn Orogen of Western Australia, was regarded as an orogenic gold deposit that formed at ca. 1738 Ma during the assembly of Proterozoic Australia. However, the trace element chemistry of the pyrite crystals closely resembles those of the Carlin deposits of Nevada, with rims that display solid solution gold accompanied by elevated As, Cu, Sb, Hg, and Tl, surrounding gold-poor cores. New SHRIMP U-Pb dating of xenotime intergrown with auriferous pyrite and ore-stage alteration minerals provided a weighted mean 207Pb*/206Pb* date of 1769 +/- 5 Ma, interpreted as the age of gold mineralization. This was followed by two discrete episodes of hydrothermal alteration at 1727 +/-7Ma and 1673 +/- 8 Ma. The three ages are linked to multiple reactivation of the crustal-scale Nanjilgardy Fault during repeated episodes of intracratonic reworking. The regional-scale drivers for Carlin-like gold mineralization at Mount Olympus are related to a change in tectonic regime during the final stages of the intracratonic 1820-1770 Ma Capricorn Orogeny. Our results suggest that substantial sized Carlin-like gold deposits can form in an intracratonic setting during regional-scale crustal reworking.
Funding
Australian Research Council
AMIRA International Ltd
ARC C of E Industry Partner $ to be allocated
Anglo American Exploration Philippines Inc
AngloGold Ashanti Australia Limited
Australian National University
BHP Billiton Ltd
Barrick (Australia Pacific) PTY Limited
CSIRO Earth Science & Resource Engineering
Mineral Resources Tasmania
Minerals Council of Australia
Newcrest Mining Limited
Newmont Australia Ltd
Oz Minerals Australia Limited
Rio Tinto Exploration
St Barbara Limited
Teck Cominco Limited
University of Melbourne
University of Queensland
Zinifex Australia Ltd
History
Publication title
Geoscience FrontiersVolume
10Pagination
89-105ISSN
1674-9871Department/School
School of Natural SciencesPublisher
Zhongguo Dizhi Daxue, China University of GeosciencesPlace of publication
ChinaRights statement
Copyright 2018 China University of Geosciences (Beijing) and Peking University. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/Repository Status
- Open