Evidence of glacial processes within the Lefroy Drainage System, Western Australia

Large-scale drainage systems traversing the Yilgarn Craton, Western Australia, have a long-debated mechanism of origin. In the northern parts of the Yilgarn Craton, direct evidence exists for their creation and fill by glacial processes (bed rock striations, polished pavements, infill of drainages by tillite), although similar evidence has not been recognised in the southern Lefroy Drainage System. This paper presents the first detailed evidence for glacially influenced sediments including pebbly diamictite, with preserved features suggesting glacial origin within the Lefroy Drainage System. This is based on data collected from field localities east of Lake Lefroy and describes the geological and paleoenvironmental history of these outcrops. Additionally, subsurface data are utilised to describe glacial morphologies from Lefroy Drainage System. These data support regional correlations of this scour and fill to other drainages across the Yilgarn Craton.