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

摘要

The felsic-dominant Gawler Range Volcanics and cogenetic Hiltaba Suite granitoids constitute the ca. 1590 Ma 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 Cu-U-Au-Ag deposit and the Wirrda Well Cu-Au prospect. Laser Ablation Inductively Coupled Plasma Mass Spectrometry U-Pb dating results (un-anchored) of apatite in the basalts and dykes at Mount Gunson (1576 +/- 33 Ma), Wirrda Well (1596 +/- 17 Ma), and Olympic Dam (1621 +/- 20 Ma) confirm their effective temporal correlation with the ca. 1590 Ma Gawler silicic large igneous province.