Late Permian U-Pb CA-IDTIMS isotope geochronology of the Bowen Basin, Eastern Australia

Abstract

High-resolution geochronology with an age resolution at the permil or sub-permil levels has the potential to internationally calibrate Late Permian peri-Gondwanan sequences in the Bowen Basin. Previous attempts at such calibration have relied on carbon-isotope records and very tenuous biostratigraphic and lithostratigraphic correlations here deemed unsuitable for a high-resolution chronostratigraphic framework for the basin. Existing SHRIMP U-Pb ages for some tuffs in the basin have been compromised by inaccuracy and low precision when compared to the CA-IDTIMS method. High-precision CA-IDTIMS ages also allow us to correlate individual tuff beds across the basin, to estimate rates of climatic and biotic change between the late Guadalupian and late Changhsingian major Permian mass extinctions. We here report seven new U-Pb CA-IDTIMS ages for ash-tuffs in the Late Permian of the Bowen Basin.