Climate and related controls on interglacial fluvial sedimentation in lowland Britain

Interglacial fluvial sediment sequences are common in lowland Britain where their palaeontology has been considerably studied but their sedimentology is poorly known. By contrast, Holocene (Flandrian) sequences have yielded important insights into river, and thus, environmental evolution. This paper examines the nature of the interglacial fluvial sedimentary record in southern Britain, showing similarities and differences in the sedimentary record. A four-phase pattern of fluvial behaviour through an interglacial cycle is presented. The utility of using Holocene sequences as analogues for previous interglacial sedimentation is discussed and an attempt is made to explain the proposed four-phase pattern in terms of predictable fluvial responses to an interglacial climate cycle. Finally, the implications of the pattern for alluvial unit preservation and the stratigraphical interpretation of Pleistocene temperate events from river sediments are highlighted. It is shown that British lowland rivers normally adopt three major behavioural modes in the Pleistocene: braided or wandering gravel-dominated mode, fine-sediment-dominated stable meandering to anastomosing mode, and incision or non-depositional mode.