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142440 - Geology and geochronology of the two - author version.pdf (7.07 MB)
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Geology and geochronology of the Two-Thirty prospect, Northparkes district, NSW

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journal contribution
posted on 2023-05-20, 20:22 authored by Wells, TJ, David CookeDavid Cooke, Michael BakerMichael Baker, Lejun ZhangLejun Zhang, Sebastien MeffreSebastien Meffre, Jeffrey SteadmanJeffrey Steadman, Norman, MD, Hoye, JL
The Northparkes district, central New South Wales, hosts several economic Cu–Au deposits associated with discrete, thin, porphyry intrusive complexes emplaced in the Late Ordovician during formation of the Macquarie Arc. The recently discovered Two-Thirty Cu–Au–(Mo) prospect is a mineralised magmatic–hydrothermal breccia complex that is hosted by the moderately east-dipping Goonumbla Volcanic Complex on the western limb of the Milpose Syncline ∼15 km south of the Northparkes porphyry district. Generation of the magmatic–hydrothermal breccia complex is interpreted to be related to the 448.0 ± 4.4 Ma emplacement of the Two-Thirty porphyry. However, Re–Os dating of molybdenite from the breccia complex indicates a potential for a ca 440 Ma mineralising event that has similar timing to economic porphyry mineralisation in the Northparkes district. The discovery of the Two-Thirty prospect has important implications for exploration in the Northparkes district and the broader Macquarie Arc. Two-Thirty is only the second known occurrence of magmatic-hydrothermal breccia-hosted mineralisation discovered within the Macquarie Arc, with the other being Cadia Quarry. Mineralisation at Two-Thirty is potentially older than the Northparkes and Cadia deposits, and younger than the epithermal and calc-alkaline deposits at Cowal, Marsden and Ridgeway.

Key Points:

  1. The Two-Thirty is a polyphase magmatic–hydrothermal breccia complex that hosts Cu–Au (Mo).
  2. The Two-Thirty is the first significant breccia-hosted mineralisation found in the Northparkes district.
  3. U–Pb zircon crystallisation ages of the causative intrusion at Two-Thirty pre-date mineralisation at Northparkes.
  4. Re–Os dates of molybdenite from the Two-Thirty breccia complex are coeval with syn-mineralisation at Northparkes, supporting the model of periodic release of melts and fluids from underlying magma chambers during the formation of porphyry mineralisation in the Northparkes district.


Australian Research Council

Alkane Exploration NL

AngloGold Ashanti Australia Limited

CMOC Mining Services Pty Ltd T/A Northparkes Mines

Department of Economic Development, Jobs, Transport and Resources

Department of State Growth (Tas)

Emmerson Resources Limited

Evolution Mining

Geological Survey of New South Wales - Department of Industry

Geoscience Australia

Heron Resources Limited

New South Resources Limited

Rio Tinto Limited

Sandfire Resoures NL


Publication title

Australian Journal of Earth Sciences










School of Natural Sciences


Blackwell Publishing Asia

Place of publication

54 University St, P O Box 378, Carlton, Australia, Victoria, 3053

Rights statement

Copyright 2021 Geological Society of Australia

Repository Status

  • Open

Socio-economic Objectives

Copper ore exploration; Expanding knowledge in the earth sciences