Provenance of the Early Mesoproterozoic Radium Creek Group in the northern Mount Painter Inlier : correlating isotopic signatures to inform tectonic reconstructions

摘要

New in situ zircon LA-ICPMS geochronologic and Hf-isotope data from the Radium Creek Group within the Mount Painter Inlier provide important temporal constraints on the Early Mesoproterozoic palaeogeography of eastern Proterozoic Australia. The entire Radium Creek Group was deposited in a single basin forming phase, and has a maximum depositional age of 1595 ± 3.7 Ma. Detrital zircon from these metasedimentary rocks have U-Pb age populations at ca. 1595 Ma, 1660-1680 Ma, 1710-1780 Ma, ca. 1850 Ma and ca. 2500 Ma. These grains are characterised by isotopically diverse and evolved sources, and have crystallised within predominantly felsic igneous host-rocks. The relative age spectra and isotopic character has more similarity with the Gawler Craton than the Arunta Block, Curnamona Province or the Mount Isa Inlier. These observations suggest that the Mount Painter Province was adjacent to the Gawler Craton in the Early Mesoproterozoic. Our data supports a coherent South Australian Craton at ca. 1595 Ma and a contiguous continental mass that included the North and South Australian cratons. The Mount Painter Inlier occupied a complex plate tectonic setting in the overriding plate of two convergent margins.