New age constraints for the Tommy Creek Domain of the Mount Isa Inlier, Australia
Brown, A., Spandler, C., and Blenkinsop, T.G. (2023) New age constraints for the Tommy Creek Domain of the Mount Isa Inlier, Australia. Australian Journal of Earth Sciences, 70 (3). pp. 358-374.
|
PDF (Published Version)
- Published Version
Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (8MB) | Preview |
Abstract
The Tommy Creek Domain is a complex, yet little studied, terrane in the Eastern Subprovince of the Mount Isa Province, northwest Queensland Australia. In this study, we take advantage of modern low-cost and rapid geochronology techniques to undertake an iterative dating approach integrated with detailed fieldwork to define the ages and extents of numerous lithologies and units of the Tommy Creek Domain. This includes some units not previously identified, lithologies previously grouped together based on field observations but now shown to have multiple distinct ages and dates not commonly represented in Mount Isan time–space plots. We identify an episode of felsic magmatism at ca 1640 Ma, and multimodal intrusions (ca 1615 Ma) immediately preceding the onset of the Isan Orogeny. A major rock package of the Tommy Creek Domain, the Milo beds, are characterised here as the youngest pre-Isan Orogeny sedimentary unit in the Eastern Subprovince (1660–1620 Ma), confirming that sedimentation and possibly rifting continued after deposition of the Soldiers Cap, Mount Albert and Kuridala groups (ca 1690–1650 Ma) before the onset of the Isan Orogeny (ca 1600 Ma). The Milo beds are thus age equivalent to the Mount Isa and McNamara groups of the Western Succession. There is evidence of a compositional shift in sedimentation coincident with the ca 1640 Ma Riversleigh Inversion event, previously only observed in the Western Subprovince in the Lawn Hill Platform. The application of geochronology as part of the mapping workflow can assist with differentiating geological units in terranes where field evidence is ambiguous and can aid in the focusing of objectives for field campaigns to enable the best possible interpretations to be made.KEY POINTS New ages constrain the Milo beds in the Tommy Creek Domain as the youngest stratigraphy in the Eastern Subprovince of the Mount Isa Province. The Milo beds are age equivalents of the McNamara and Mount Isa groups of the Western Subprovince of the inlier. Recognition of felsic and mafic intrusions with ca 1640 Ma and ca 1615 Ma ages. Evidence for Riversleigh Inversion event ca 1640 in the Eastern Subprovince.
Item ID: | 78541 |
---|---|
Item Type: | Article (Research - C1) |
ISSN: | 1440-0952 |
Keywords: | geochronology, Isan Orogeny, Mount Isa Inlier, North Australian craton, Tommy Creek Domain |
Copyright Information: | © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. |
Date Deposited: | 24 Oct 2023 04:50 |
FoR Codes: | 37 EARTH SCIENCES > 3705 Geology > 370502 Geochronology @ 100% |
SEO Codes: | 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280107 Expanding knowledge in the earth sciences @ 100% |
Downloads: |
Total: 209 Last 12 Months: 24 |
More Statistics |