Journal article
Episodic gold mineralisation correlated with discrete structural events at Ballarat East, southeast Australia
AM Fairmaid, D Phillips, CJL Wilson
Ore Geology Reviews | ELSEVIER | Published : 2017
Abstract
New 40Ar/39Ar geochronological data suggest orogenic gold mineralisation at the Ballarat East deposit, southeast Australia, occurred in three main episodes at ca. 445–435 Ma, ca. 420–415 Ma and ca. 380–370 Ma. The gold mineralisation is localised in muscovite-bearing quartz and quartz-carbonate veins hosted in the steep faults (70–90°), on limbs of tight and isoclinal folds in an Ordovician turbidite sequence, and within west-dipping (≤45°) faults, historically known as leather jacket lodes. Initiation of the ≤45° faults that are confined to fold culminations, begins at ca. 445 Ma, with peak metamorphic conditions at 440 Ma. The earliest vein sets (V1), were emplaced on limb thrusts at ca. 4..
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Awarded by Appalachian Regional Commission
Funding Acknowledgements
This work was funded by ARC linkage grant LP 0882157 and support from LP150100717, Ballarat Goldfields Pty Ltd through Lihir Gold Limited (LGL) and Castlemaine Goldfields Ltd. AF also received funding from an Australian Postgraduate Award, a Baragwanath Award and support from the pmd*CRC. The authors thank Stan Szczepanski for technical assistance in the noble gas laboratory. We thank the staff at Ballarat Goldfields, in particular Matt Hernan, Stefan Valle and Justin Spalding for discussions about Ballarat geology. We also thank Darren Osborne (Lihir Gold Limited) for initial mine assistance and access to mine data and samples. Discussions with David Moore and reviews by Clive Willman and John Miller improved the final manuscript.