Palynostratigraphy of the murray basin, inland Southeastern Australia

Abstract

To date, the only published comprehensive zonation for dating and correlating late Tertiary non‐marine sequences in Australia is that developed in the 1970s for the offshore Gippsland Basin on the extreme southeastern margin of the continent. In this paper an analogous zonation scheme is presented for the Murray Basin, a large intracratonic basin that covers some 300 000 km2 of inland New South Wales, Victoria and South Australia. Major spore and pollen sequences identified within this basin correspond with major periods of marine transgression‐regression, in the middle Eocene to early Oligocene, early Oligocene to middle Miocene and late Miocene to Pliocene. Presence/absence data allow the first two sequences to be subdivided into palynological zones that can be confidently correlated with zones established for the Gippsland Basin, viz., equivalents of the middle to late Eocene lower, middle and upper Nothofagidites asperus zones, and the Oligocene to middle Miocene Proteacidites tuberculatus and Canthiumidites bellus zones, respectively. Late Miocene‐early Pliocene and late Pliocene‐Pleistocene intervals are assigned to the Monotocidites galeatus Zone and Tubulifloridites pleistocenicus Zone, respectively. Changes in the relative abundance of commonly occurring species support the above subdivisions in a general way only and are not reliable as a basis for basin‐wide correlations. Until some independent geological or geophysical datum is found to allow a direct comparison of species time distributions across the basin, further formal subdivision of the zones is not recommended.