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Neoproterozoic (ca. 820830 Ma) mafic dykes at Olympic Dam, South Australia: links with the Gairdner Large Igneous Province

Citation

Huang, Q and Kamenetsky, VS and McPhie, J and Ehrig, K and Meffre, S and Maas, R and Thompson, J and Kamenetsky, M and Chambefort, I and Apukhtina, O and Hu, Y, Neoproterozoic (ca. 820-830 Ma) mafic dykes at Olympic Dam, South Australia: links with the Gairdner Large Igneous Province, Precambrian Research, 271 pp. 160-172. ISSN 0301-9268 (2015) [Refereed Article]

Copyright Statement

2015 Elsevier B.V. All rights reserved.

DOI: doi:10.1016/j.precamres.2015.10.001

Abstract

A suite of basaltic to doleritic dykes (named the Olympic Dam dolerite) has been intersected in drill holes at the Olympic Dam iron oxide CuUAuAg deposit in the Gawler Craton, South Australia. The dykes intrude the ca. 1600 Ma Roxby Downs Granite as well as the Olympic Dam Breccia Complex, and range from several centimetres to over 100 m in width, strike NW and dip subvertically. Clinopyroxene and plagioclase are the major minerals, together with accessory apatite and Ti-magnetite. Magmatic apatite crystals in medium-grained doleritic dykes have been dated by LA-ICPMS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry), and yielded a UPb age of 825 18 Ma. The Olympic Dam dolerite has invariably been altered. Secondary apatite and titanite crystals from post-magmatic veinlets cutting the same dykes give similar results of 821 15 Ma and 817 11 Ma, respectively. All these results are, within error, coincident in age with the Gairdner Dyke Swarm, the longest dyke swarm (∼1000 km in length) in Australia. The Olympic Dam dolerite shows similar compositional trends and variations to the Gairdner Dyke Swarm, especially in terms of the relatively immobile High Field Strength Elements (HFSE) and Rare Earth Element (REE). We conclude that the Olympic Dam dolerite belongs to the Gairdner Dyke Swarm, expanding its known extent and compositional range. The Gairdner Dyke Swarm is a major component of the ca. 820 Ma Gairdner Large Igneous Province (LIP) generated during the break-up of the supercontinent Rodinia. The ca. 1070 Ma Warakurna and the ca. 820 Ma Gairdner LIP in Australia are compositionally distinct, whereas the Gairdner LIP and LIP and mafic suites associated with the break-up of Rodinia in South China and North America are broadly similar. This provides geochemical support for a Gairdner LIP origin for some mafic suites, in particular the Beda Volcanics in South Australia, and for a juxtaposition of South China, South Australia and North America in the tectonic reconstruction of Rodinia at ca. 820 Ma.

Item Details

Item Type:Refereed Article
Keywords:Olympic Dam, Gairdner Dyke Swarm, Large Igneous Province, Rodinia, dolerite, apatite U-Pb
Research Division:Earth Sciences
Research Group:Geology
Research Field:Igneous and Metamorphic Petrology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Huang, Q (Mr Qiuyue Huang)
Author:Kamenetsky, VS (Professor Vadim Kamenetsky)
Author:McPhie, J (Professor Jocelyn McPhie)
Author:Meffre, S (Dr Sebastien Meffre)
Author:Thompson, J (Mr Jay Thompson)
Author:Kamenetsky, M (Dr Maya Kamenetsky)
Author:Chambefort, I (Dr Isabelle Chambefort)
Author:Apukhtina, O (Miss Olga Apukhtina)
ID Code:104086
Year Published:2015
Funding Support:Australian Research Council (LP130100438)
Web of Science® Times Cited:11
Deposited By:Earth Sciences
Deposited On:2015-11-03
Last Modified:2017-10-30
Downloads:0

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