Sedimentology of Late Devensian glaciofluvial outwash in the Don Valley, Grampian Region

Synopsis Detailed sedimentological investigations in the Don Valley, Grampian Region, have allowed the subdivision of the outwash succession into four main lithofacies associations, namely proximal braided outwash, distal braided outwash, overbank deposits and distal alluvial fan deposits. In addition two types of diamicton have been identified; firstly, basal diamicton sheets which mantle bedrock and are interpreted as probable lodgement tills and, secondly, more localised diamictons capping and interbedded with the outwash deposits, which are interpreted as debris flows from ice (‘flow tills’). Many of these successions display deformation features and faulting as a probable consequence of deposition on top of and banked against stagnant ice. This provides evidence for the style of deglaciation of the Don Valley which was by stagnation and in situ melting rather than by active retreat.