Interglacial pollen and plant macrofossils from Langdon River, western Tasmania

Abstract

Pollen and plant macrofossils from Langdon liner give an interglacial floral record for western Tasmania. The location of the site between the ice limits of the Last or Margaret Glaciation and the Penultimate or Henty Glaciation indicate that it cannot be younger than the Last Interglacial. The sequence of vegetation changes shows the succession Casuarina Phyllocladus-Nothofagus with Casuarina as pioneer and Nothofagus as representing Maximum wet forest development. After the maximum the presence of Phyllocladus-Nothofagus-Eucalyptus-Microstrobos suggests deterioration to subalpine woodland/shrubland, and Compositae, Gramineae-Microstrobos to alpine shrubland and herbland. The sequence represents most of a glacial-interglacial-glacial cycle Of environmental changes that occurred before 43 000 14C yr B.P. Very high Casuarina values occur in the early part at the interglacial sequence which contrasts with the Holocene where Eucalyptus is more important than Casuarina. Otherwise the sequence of Phyllocladus, Nothofagus, Eucryphia-Anodopetalum is the same as for Holocene forest development. The interglaeial ‘optimum’ is marked by the occurrence of Pomaderris apetala type and Dicksonia antarctica. There is some similarity with the Casuarina curves in the Lake George interglacials before the Last Interglacial. But, on the whole, there is more similarity with interglacial rainforest development in western South Island, New Zealand Only one cycle of vegetation change is recognized at Langdon River which is unlike New Zealand and central Chilean records from 40-42° S which in different ways record a mid Last Interglacial climatic deterioration.