Changes in channel–floodplain processes of the north Jiudong Basin, NW China, connected with climate change across the mid‐Pleistocene

Abstract Knowledge of how the avulsion style of river, channel mobility and floodplain reworking changes under different paleoclimatic conditions, helps to understand the morphodynamics of fluvial intrinsic behaviours and its impact on shaping basin alluvial stratigraphic architecture. In order to elucidate the relationship between extrinsic factors and internal fluvial processes, here, we explored how river morphodynamics change across the mid‐Pleistocene climate change. Sedimentary facies analyses in the Jiudong Basin of western‐central Hexi Corridor were applied to constrain changes in channel‐floodplain processes. Ten lithofacies and nine facies associations involved in general shallow lake, delta front, delta plain, overbank and channel sub‐environments were identified. These data do show evidence of elevated channel mobility, floodplain reworking and avulsion style changed significantly after 0.8 Ma. Taken together with studies of erosion rate/sediment flux variability and paleoclimate evidence from the region, the most plausible explanation of these findings from the Jiudong Basin is that, sedimentary processes subjected to declining vegetation and floodplain cohesiveness, due to a dry and unstable climate, experienced accelerated channel dynamics after 0.8 Ma. In the context of climate change across the mid‐Pleistocene, these findings provide an important perspective on the complex links between fluvial dynamics, floodplain reworking and climate change.