Stratigraphic palynology from shallow bores in the Namoi River and Gwydir River valleys, north-central New South Wales

The palynology of over fifty bores drilled into the Cainozoic sediments covering the Coonamble Embayment, Broomi Trough and Lightning Ridge Shelf of the Surat Basin are reported here.The Early Cretaceous bedrock is either the Dictyotosporittes spectosus Zone or less frequently, the Crybelosporttes stylosus Zone, and is encountered everywhere.(1) the mid-late Miocene Trtporopollenites bellus Zone which has a patchy distribution It is restricted to the deeper, consistently grey clays, and in some bores, ments are: throughout the area.The Cainozoic alluvial sedidirectly overlies the Early Cretaceous bedrock: (2) Pliocene-Pleistocene assemblages found only near Narrabri and (3) Pleistocene assemblages near Moree.Tertiary deposition on the Early Cretaceous landscape started in the mid-late Miocene.The vegetation must have been a floristically rich closed forest, and the rainfall at least 150cm per annum.There was a subsequent decrease in rainfall.verse, but there were still substantial areas of closed forest.The Pliocene-Pleistocene floras are less di-The Pleistocene floras represent open woodland with a well developed herbaceous ground cover.