An early pliocene pollen assemblage from Lake Tay, south-western Australia, and its phytogeographic implications

Abstract

Pollen assemblages indicate an Early Pliocene age for sediments in the Lake Tay area, south-west of Norseman, W.A. They also show unexpected similarities to assemblages of the same age from south-eastern Australia and suggest that regional phytogeographic differentiation of the flora of southern Australia was less pronounced in the Early Pliocene than usually supposed. This implies that considerable regional differentiation of southern Australian floras has taken place in a relatively short period, principally during the past 4 or 5 million years. Although the dominant elements in the pollen spectrum indicate a warm temperate open-forest with a lake edge or marsh component, small numbers of the pollen of Nothofagus (brassii-type) and some podocarpaceous conifers are also present. These suggest a wetter climate and may have derived from small stands surviving in refugia on high country to the east or south of Lake Tay.