The Late Permian-Early Triassic palynology of the Bowen and Sydney basins: results and implications of new CA-IDTIMS isotopic ages

Abstract

Palynology is the principal biostratigraphic tool employed to correlate among the thick fluvial to shallow marine successions of the Permian-Early Triassic of the Bowen and Sydney basins of eastern Australia. The regional palynofloras can be utilised for intra-continental comparisons but are only broadly correlative across Gondwana and rarely applicable as stage or sub-stage level of global tie-points. High precision CA-IDTIMS dating of Middle Permian-Early Triassic ashfall tuffs in these basins has provided a unique opportunity to confidently tie the endemic fossil biota to the international timescale. Carbonaceous siltstones and coals bracketing the tuff beds have been processed for their palynological content thus enabling precise chronometric ages to be ascribed to the fossil biotas. Tying these biozones to the internationally accepted Geologic Timescale will greatly enhance the event and biozonation correlation to areas outside Australia.