Havieron Summary Explanation
The Greatland Gold Havieron Project is located in North Western Australia on the edge of the Archaean Pilbara Craton within an ancient mountain belt known as the Paterson Orogen. The Paterson Orogen stretches 2000km across Australia and is an arcuate belt of folded, metamorphic sedimentary and igneous rocks (Bagas 2004). The Havieron project is located in the North-Western part of this orogen. The Paterson Orogen first developed in response to a collision between the North Australian Craton and the Western Austalia Craton at approximately 1830-1765 million years ago (Ma) (Bagas 2004). From that starting point; there have been three important mountain-building phases (orogenies):
- Yupungku Orogeny
- Miles Orogeny
- Paterson Orogeny
These orogenic episodes have deformed, folded and metamorphosed the sedimentary and igneous rocks within the Paterson Orogen.
The Havieron project contains Au-Cu mineralization hosted within the Neoproterozoic basement metasedimentary rocks of the Lamil Group. The Neoproterozoic is any time between 1 billion years ago (1ga) and 541 million years ago (IUGS 2020). The age range covers the majority of the rocks at Havieron and the Miles + Paterson Orogens. The Lamil Group was fully deposited by 820Ma in the Yeneena Basin (Bagas and Nelson 2007). Rock types within the Lamil Group consist of shallow marine sandstones, limestones and some shales. The Group is split into three formations:
- The Malu Formation – oldest
- The Puntapunta Formation
- The Wilki Formation – youngest
The Malu formation hosts the Telfer deposit, whilst it appears that the Puntapunta formation is the host of the Havieron deposit which is stratigraphically younger. The Puntapunta formation contains laminated to thinly bedded dark grey dolomitic sandstone, dolomitic siltstone, chert, shale, and limestones (Schindler et al 2016). This sequence of rocks is intruded by numerous granites in the region dated between 650-600 million years ago (Maidment et al 2011). These granites include:
- The Mount Crofton Granite
- Minyari Granite
- O’Callaghans Granite
- Wilki Granite
Despite some debate in the literature, it is hypothesised based on studies at Telfer that the granites are important in the mineralization in the Paterson. During the Miles Orogeny, the granites were emplaced and subsequent hydrothermal fluids were able to take up metals such as Au and Cu possibly from the surrounding sediments. These fluids travel along faults, fractures and through permeable layers before depositing these metals. The Puntapunta formation is where the Au-Cu has ended up in this case. Although there are a few models for how hydrothermal fluids can brecciate the rock, the simplest is hydraulic fracturing whereby the force of the fluid overcomes the lithostatic pressure of the rock causing the rock to brecciate or collapse. Mineralization at Havieron includes; pyrite, pyrrhotite and chalcopyrite. The Gold is associated with these sulphide minerals and is likely occurring as inclusions within the sulphides themselves.
Based on current observations, published information and comparisons to Telfer, Havieron is considered to be a Telfer analogue and is characterized as an intrusion-related gold deposit that formed during the Neoproterozoic. The deposit is located approximately 400m+ depth, under Permian rock cover. For more information watch the Paterson presentations or contact Magictrades212@gmail.com.
- Bagas L (2000) Geology of the Paterson 1:100 000 sheet. Geological Survey of Western Australia, 1:100 000 Geological Series Explanatory Notes
- Bagas L (2004) The Neoproterozoic Throssell Range and Lamil Groups, northwest Paterson Orogen, Western Australia – a field guide. West Austr Geol Surv Rec 2004/15
- Bagas, L. and Nelson, D.R., 2007. Provenance of Neoproterozoic sedimentary rocks in the northwest Paterson Orogen, Western Australia. In Central Australian Basins Symposium Special Publication.
- Maidment, D.W., Huston, D.L. and Heaman, L., 2010. The age of the Telfer Au-Cu deposit and its relationship with granite emplacement, Paterson Province, Western Australia. Geoscience Australia.
- C. Schindler, S. G. Hagemann, D. Banks, T. Mernagh, A. C. Harris; Magmatic Hydrothermal Fluids at the Sedimentary Rock-Hosted, Intrusion-Related Telfer Gold-Copper Deposit, Paterson Orogen, Western Australia: Pressure-Temperature-Composition Constraints on the Ore-Forming Fluids. Economic Geology ; 111 (5): 1099–1126