Evidence for a 1750–1710 Ma orogenic event, the Wonga Orogeny, in the Mount Isa Inlier, Australia: implications for the tectonic evolution of the North Australian Craton and Nuna Supercontinent

Spence, Joshua S., Sanislav, Ioan V., and Dirks, Paul H.G.M. (2022) Evidence for a 1750–1710 Ma orogenic event, the Wonga Orogeny, in the Mount Isa Inlier, Australia: implications for the tectonic evolution of the North Australian Craton and Nuna Supercontinent. Precambrian Research, 369. 106510.

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Abstract

In this contribution we propose that Mount Isa Inlier was affected by a new orogeny, the Wonga Orogeny, which occurred between 1750 and 1710 Ma. Evidence for this event is principally given by structural field data and geochronology from this study and that documented in Spence et al. (2021). In this study, field relationships and geochronology within the Duchess Belt of the Mary Kathleen Domain reveals two main deformation events during the Wonga Orogeny, here D1 and D2. The former produced predominantly upright, tight, east–west trending folds whereas the latter produced upright to overturned, north–south trending folds. D1 can be constrained between 1741 ± 6 Ma to 1736 ± 3 Ma, based on the U-Pb magmatic zircon ages of the Revenue granite which intrudes prior to or early during D1 and the intrusion of the Overlander granite which has not been affected by D1. The age of the D2 event can be constrained between 1736 ± 3 Ma and 1722 ± 7 Ma based on the U-Pb magmatic zircon ages of the Overlander granite which intrudes prior to or early during D2 and the Myubee granite which intrudes syn-D2 – within the fold hinge of an F2 anticline. These timing relationships coupled with F2 folds associated with mineral lineations (L2) defined by biotite and hornblende, as well as syn-D2garnet, kyanite and sillimanite porphyroblasts suggest that amphibolite-facies metamorphism, deformation and contemporaneous magmatism defined by the Wonga and Burstall Suite magma’s all occurred between 1750 and 1710 Ma. These characteristics typically define orogenesis and is here, accordingly proposed as a third orogenic event within the Mount Isa Inlier. These findings have implications on the tectonic evolution of the North Australian Craton and Nuna Supercontinent.

Item ID: 71216
Item Type: Article (Research - C1)
ISSN: 1872-7433
Keywords: Mount Isa Inlier, North Australian Craton, Leichhardt Superbasin, Duchess Belt, Nuna
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Copyright Information: Crown Copyright © 2021 Published by Elsevier B.V. All rights reserved.
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For access to geochronology data please visit https://osf.io/t65nu/ (Open Science Framework).

Date Deposited: 06 Feb 2022 23:45
FoR Codes: 37 EARTH SCIENCES > 3705 Geology > 370502 Geochronology @ 40%
37 EARTH SCIENCES > 3705 Geology > 370503 Igneous and metamorphic petrology @ 20%
37 EARTH SCIENCES > 3705 Geology > 370511 Structural geology and tectonics @ 40%
SEO Codes: 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280107 Expanding knowledge in the earth sciences @ 100%
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