MIDDLE TERTIARY DINOFLAGELLATE AND SPORE POLLEN BIOSTRATIGRAPHY AND PALEOECOLOGY OF THE MALLEE CLIFFS BORE, CENTRAL MURRAY BASIN

Spores, pollen and dinoflagellates haw been recovered from all strata from the Late Eocene to the Mid Miocene in the Mallee Cliffs bore. The sequence includes the Early - Mid Miocene marine transgression. Dinof lagellates are found throughout the sequence, but they are rare in the Late Eocene, except for two horizons where conditions would have been more marine. The Early - Mid Miocene marine transgression sequence ha s good spore/pollen and dinoflagellate floras. Five dinoflagellate zon es/acmes are recognised and these are useful for at least local correl ation with the SADME MC63 bore in the western part of the Basin. When the dinoflagellate zonation is compared with the spore/pollen zonation , there are some minor discrepancies in the position of the boundaries , probably due to palaeogeographic and palaeoecologic factors. The spo re/pollen zonation is similar to that of the eastern, nonmarine part o f the basin, for the Late Eocene - Oligocene sequence. The Miocene mar ine sequence, however, differs in that Araucariaceae pollen is abundan t, suggesting that araucarian forests grew in coastal and/or riverine environments.