Weathering evidence for an additional glacial stage in Tasmania

Abstract

Quantitative studies of relative dating parameters, including subsUlface dolerite weathering rind thickness and weathering Font penetration, permit the differentiation of three broad groupings of til! deposits in several valleys in north-central, western, western-central and south-western Tasmania. An early cold climatic phase-the Linda Glacial Stage-is recognised on the basis of this weathering evidence which also indicates that there have been at least two more recent Glacial Stages of decreasing severity, termed here the Henty and Margaret Glacial Stages respectively. This three-fold model bears a striking similarity to that of Lewis (1945) which was rejected nearly three decades ago. However, whereas Lewis' model was founded upon erosional evidence, the present study is based entirely upon depositional and weathering evidence.