PRELIMINARY ENVIRONMENTAL RECONSTRUCTIONS FROM LATE QUATERNARY POLLENAND MOLLUSK ASSEMBLAGES AT EGG LAGOON, KING-ISLAND, BASS STRAIT

A late Quaternary environmental record is currently being developed fr om Egg Lagoon, King Island, Bass Strait, a site which is geographicall y well situated to contribute towards a history of the Bass Strait reg ion. Environmental reconstructions are based on a stratigraphic survey and pollen, charcoal and mollusc analyses of sediment core samples. T he recorded stratigraphy includes five sedimentary units representing estuarine-marine, freshwater lake and swamp depositional environments. Amino-acid racemization analyses of marine shells indicate a greater than last interglacial age for the basal estuarine-marine unit, while radiocarbon analyses of organic muds and wood suggest that a substanti al section of the overlying freshwater lake and swamp facies is beyond the conventional limit for this technique. Local pollen assemblages r epresent freshwater lake and swamp plant communities that have varied presumably according to water level changes at the site. Regional poll en assemblages represent terrestrial herbaceous communities, believed to have existed under cooler and drier climates than today, and Eucaly ptus- and Phyllocladus-dominated forests and woodlands from periods wi th greater effective precipitation than at present. A sustained increa se in charcoal representation dating from at least 39 000 years before the present may indicate an anthropogenically induced change in the f ire regime, consistent with the earliest dates for human occupation in mainland Tasmania.