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Geology and geochronology of the Two-Thirty prospect, Northparkes district, NSW

Citation

Wells, TJ and Cooke, DR and Baker, MJ and Zhang, L and Meffre, S and Steadman, J and Norman, MD and Hoye, JL, Geology and geochronology of the Two-Thirty prospect, Northparkes district, NSW, Australian Journal of Earth Sciences, 68, (5) pp. 659-683. ISSN 0812-0099 (2021) [Refereed Article]


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Copyright 2021 Geological Society of Australia

DOI: doi:10.1080/08120099.2021.1861095

Abstract

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.

Item Details

Item Type:Refereed Article
Keywords:Macquarie Arc, Northparkes, porphyry, magmatic-hydrothermal breccia, Cu-Au (Mo)
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Exploration geochemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Wells, TJ (Mr Tristan Wells)
UTAS Author:Cooke, DR (Professor David Cooke)
UTAS Author:Baker, MJ (Dr Michael Baker)
UTAS Author:Zhang, L (Dr Lejun Zhang)
UTAS Author:Meffre, S (Dr Sebastien Meffre)
UTAS Author:Steadman, J (Dr Jeffrey Steadman)
ID Code:142440
Year Published:2021 (online first 2020)
Funding Support:Australian Research Council (LP160100483)
Deposited By:CODES ARC
Deposited On:2021-01-18
Last Modified:2021-07-12
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