Detrital zircon analysis from the Galilee Basin, Queensland.

Abstract

The effect of the Permian onset of the Hunter-Bowen Orogeny on sedimentation patterns in the eastern Galilee Basin of Queensland was investigated through a comparison of age populations of detrital zircon grains in sandstones in the Cisuralian (early Permian) Joe Joe Group and the Lopingian (late Permian) Betts Creek beds and a potential shift in sediment provenance has been recognised. One key well (OEC Glue Pot Creek 1) was selected from the eastern Galilee Basin for detrital zircon analysis. The well intersected both Cisuralian and Lopingian strata. Nine sandstone samples were collected (three from the Cisuralian and six from Lopingian) and zircon grains were extracted. U-Pb isotopic data was gathered using the Laser Ablation – Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) technique. A total of 286 concordant ages were obtained from the nine samples. The Cisuralian samples have a varied age population range, with multiple peaks between 300 and 1200 Ma, suggesting numerous sources and orogenic recycling. In contrast, the Lopingian samples have a dominant peak of 250 to 300 Ma zircons, with a singular minor peak of 1500 Ma zircons, suggesting a transition in provenance between the Cisuralian and Lopingian.