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Olivine-phyric basalt in the Mesoproterozoic Gawler silicic large igneous province, South Australia: Examples at the Olympic Dam Iron Oxide Cu-U-Au-Ag deposit and other localities

Citation

Huang, Q and Kamenetsky, VS and Ehrig, K and McPhie, J and Kamenetsky, M and Cross, K and Meffre, S and Agangi, A and Chambefort, I and Direen, NG and Maas, R and Apukhtina, O, Olivine-phyric basalt in the Mesoproterozoic Gawler silicic large igneous province, South Australia: Examples at the Olympic Dam Iron Oxide Cu-U-Au-Ag deposit and other localities, Precambrian Research, 281 pp. 185-199. ISSN 0301-9268 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 Elsevier B.V.

DOI: doi:10.1016/j.precamres.2016.05.019

Abstract

The felsic-dominant Gawler Range Volcanics and cogenetic Hiltaba Suite granitoids constitute the ca. 1590Ma Gawler silicic large igneous province in the Gawler Craton, South Australia. The province includes minor occurrences of olivine-phyric basalt at Kokatha and Mount Gunson. In this study, we describe additional olivine-phyric basalts and dykes intersected by drill holes at the Olympic Dam Iron Oxide CuUAuAg deposit and the Wirrda Well CuAu prospect. Laser Ablation Inductively Coupled Plasma Mass Spectrometry UPb dating results (un-anchored) of apatite in the basalts and dykes at Mount Gunson (157633Ma), Wirrda Well (159617Ma), and Olympic Dam (162120Ma) confirm their effective temporal correlation with the ca. 1590Ma Gawler silicic large igneous province.

Compositions of Cr-spinel inclusions enclosed in former olivine phenocrysts (forsterite number >80) in basalts at Mount Gunson, Wirrda Well and Olympic Dam imply derivation from a heterogeneous mantle source that may have been modified by subduction. Least-altered olivine-phyric basalts at Mount Gunson and Kokatha are characterized by negative Nb and Ta anomalies, which are typical of arc basalts but are also common in back-arc basin basalts, in accordance with the result suggested by the Cr-spinel source indicator. The mafic components of the Gawler Range Volcanics generally have higher Zr contents and Zr/TiO2 ratios than those of high-Mg basalts and picrites produced in variable tectonic settings worldwide, possibly reflecting continental crustal components involved in their mantle source.

High abundances (typically ∼20vol.%) of former olivine phenocrysts in the basalt at Olympic Dam imply high-Mg whole-rock compositions and a high temperature of the primary magma. This result is consistent with previous models in which the heat flux from mantle magmas caused large-scale partial melting of crustal rocks that subsequently gave rise to silicic magmas erupted and intruded to form the Gawler silicic large igneous province.

Item Details

Item Type:Refereed Article
Keywords:Gawler silicic large igneous province, olivine-phyric basalt, apatite-UPb dating, Cr-spinel, petrogenesis, Olympic Dam
Research Division:Earth Sciences
Research Group:Geology
Research Field:Tectonics
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:Kamenetsky, M (Dr Maya Kamenetsky)
Author:Meffre, S (Dr Sebastien Meffre)
Author:Chambefort, I (Dr Isabelle Chambefort)
Author:Direen, NG (Dr Nicholas Direen)
Author:Apukhtina, O (Miss Olga Apukhtina)
ID Code:111964
Year Published:2016
Funding Support:Australian Research Council (LP130100438)
Web of Science® Times Cited:3
Deposited By:CODES ARC
Deposited On:2016-10-18
Last Modified:2017-10-30
Downloads:0

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