Deposition and palaeogeography of a glacigenic Neopoproterozoic succession in the east Kimberley, Australia

Abstract

Facies, provenance and palaeocurrent analysis of the predominantly siliciclastic Neoproterozoic succession of the east Kimberley district of northwestern Australia indicates southwesterly-directed regional palaeoice-flow directions associated with continental glaciation. Facies relationships at three key study sites in the east Kimberley record glacial advance, retreat and marine transgression and the likely effects of ice dynamics on local basin depositional history. Ice-scour linked with provenance data indicate ice advance from the northeast. Additional ice-flow data from the west Kimberley and the Daly River area of Northern Territory are consistent and record a regional palaeoice-flow direction towards the southwest. Palaeocurrent data and facies relationships in the east Kimberley, however, suggest that sediment transport directions within the east Kimberley basin were influenced by a combination of ice-induced lithospheric flexure, pre-existing topography and modification of basin topography and sediment dispersal paths by ice-induced redistribution of debris. A basin evolution model incorporating these concepts within the framework of ice advance, retreat and marine inundation is proposed. Identification of regional ice-flow trends of this scale should ultimately prove a useful tool in testing possible palaeogeographic reconstructions of continent configurations in a post-Rodinian world.