MAGNETOSTRATIGRAPHY OF THE LATE CENOZOIC GLACIAL SEQUENCE, PIEMAN-RIVER BASIN, WESTERN TASMANIA

The Pieman River basin, western Tasmania, has been partially occupied by ice on several occasions during the Late Cenozoic. Detrital remanen t magnetization recorded in rhythmically laminated glaciolacustrine se diments associated with glacial diamictons from the Boco, Bobadil, Bul gabac and Que drift sheets, enables the identification of drift deposi ted by glacier advances during the Brunhes, Matuyama or earlier magnet ic epochs. Mapping and discrimination of the drift sheets using morpho stratigraphic and post-depositional weathering criteria, and U/Th dati ng is supported by the magnetostratigraphy of the drifts. The palaeoma gnetic results indicate that the Boco and Bobadil Glaciations were dep osited during the Brunhes normal Chron (783 ka), and the reversed magn etization recorded in the Bulgobac Glaciation drift indicates that it was deposited prior to 783 ka. Absolute dating of the Bulgobac drifts is not yet possible, but analysis of post-depositional weathering crit eria suggests that it was probably deposited during the Matuyama rever sed Chron.