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 remanent magnetization recorded in rhythmically laminated glaciolacustrine sediments associated with glacial diamictons from the Boco, Bobadil, Bulgobac and Que drift sheets, enables the identification of drift deposited by glacier advances during the Brunhes, Matuyama or earlier magnetic epochs. Mapping and discrimination of the drift sheets using morphostratigraphic and post-depositional weathering criteria, and U/Th dating is supported by the magnetostratigraphy of the drifts. The palaeomagnetic results indicate that the Boco and Bobadil Glaciations were deposited during the Brunhes normal Chron (783 ka), and the reversed magnetization 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 criteria suggests that it was probably deposited during the Matuyama reversed Chron. © 1990 Taylor & Francis Group, LLC.