LATE CAINOZOIC GLACIATION IN WESTERN TASMANIA, AUSTRALIA

Four major Quaternary glaciations, with associated interglaciations and interstadials, have been identified in Tasmania, for which some chronological cotrol is given by radiocarbon and amino-acid assays, pollen analysis and relative weathering characteristics. The glaciations are known as the Margaret, Henty, Moore and Linda. The Margaret Glaciations has two clear stadial intervals (Isotope Stages 4 and 2), separated by the Tullabardine Interstadial dated at ca. 50-25 ka BP. An interglaciation corresponding to Isotope Stage 5 (Pieman Interglaciation) is characterised by sediments containing a pollen assemblage of a temperate rain forest. Weathered glacial deposits lying beneath the Pieman sediments are inferred to be those of the Penultimate Glaciation; three stadial moraines are identified. A preceding interglaciation (Langdon) contains wood that yielded an amino-acid ratio equivalent to the age of marine Isotope Stage 7. The following Moore Glaciation had three stadial intervals, two of which are separated by a clear interstadial (Baxter) with organic sediments that have amino-acid 'ages' equivalent to Isotope Stage 10; the non-glacial sediments have a DRM of normal polarity and are inferred to be of Mid-Quaternary age. The oldest interglaciation (Regency) is identified from organic-rich sediments (pollen assemblage of a temperate rain forest) overlying intensely weathered glacial deposits that have a DRM with reversed polarity (i.e. > 730 ka). The Linda Glaciation is the most extensive of all in Tasmania; although dating is uncertain, it has been assigned tentatively to the Early Quaternary. © 1990.