Relationships between high-K magmas and Cu–Au porphyry deposits in the Macquarie Arc, Australia
Journal Publication ResearchOnline@JCUAbstract
The Macquarie Arc is a long-lived volcanic arc terrane which began in the latest Cambrian and continued until the early Silurian. Early Silurian high-K suites associated with Cu–Au porphyry mineralization are typically considered shoshonitic; however, comparisons with well-studied examples of shoshonites in continental arcs and associated settings suggest few Macquarie Arc rocks would classify as shoshonitic. Notably, the Au-rich Cadia Intrusive Complex, which is marginally shoshonitic, and most high-K to 'shoshonitic' Macquarie Arc rocks are essentially high-K calc-alkaline, analogous to 'primitive' shoshonites generated within intraoceanic arc settings. Arc magmatism in the Macquarie Arc is consistently primitive and mantle derived prior to an increase in siliciclastic input and crustal thickening during the Silurian Benambran Orogeny, consistent with prior isotopic studies. Magma source regions can thus be interpreted as varying spatially and temporally due to variable enrichment from slab and mantle derived components, reflecting a maturing and potentially migrating arc system.
Journal
Geological Society, London, Special Publication
Publication Name
Geological Society, London, Special Publication
Volume
551
ISBN/ISSN
2041-4927
Edition
N/A
Issue
1
Pages Count
42
Location
N/A
Publisher
Geological Society Publishing House
Publisher Url
N/A
Publisher Location
N/A
Publish Date
N/A
Url
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Date
N/A
EISSN
N/A
DOI
10.1144/SP551-2024-65