Th–U disequilibrium dating of Middle and Late Pleistocene wood and shells from Banks and Victoria islands, Arctic Canada

An attempt has been made at dating Middle and Late Pleistocene deposits from Banks and Victoria islands using the Th–U disequilibrium method. Geological correlations are difficult to establish because of the discontinuous nature of the terrestrial units and the relative absence of datable fossil wood and shells. The Th–U geochemical system likely remained closed for extended periods because of the presence of permafrost, which implies very limited or absent water circulation. The Th–U age determinations obtained confirmed the previously established stratigraphic framework and provide chronological information in that samples of Sangamonian age are differentiated from those that are younger (Wisconsinan and Holocene) or older (Middle Pleistocene). The Th–U disequilibrium method carefully used in areas where water circulation is limited can thus provide chronological control for sediments older than those that can be dated by the radiocarbon method.