Accelerated uplift resulting from Anglian glacioisostatic rebound in the Middle Thames Valley, UK?: evidence from the river terrace record

A relatively simple analysis of the terraces of the Middle Thames valley re veals a complex sequence of responses to late-Anglian (late Middle Pleistoc ene) drainage disruption. A decrease in the amounts of vertical incision se parating the later post-Anglian terraces strongly suggests a major change i n the rate of incision in the Middle Thames area in the post-Anglian. A lat e Anglian and early post-Anglian incision rate of 1.45 m ka(-1) was quickly replaced by incision at a rate of 0.089 m ka(-1) in the later post-Anglian period. The lower incision rate of the later post-Anglian compares favoura bly with previous estimates of regional uplift. Two plausible explanations for the enhanced incision in the late Anglian and early post-Anglian are re cognized, one related to pending of the river by Anglian ice and the other to glacio-isostatic rebound. In the latter case, the mismatch between expec ted and actual heights of late-Anglian deposits would suggest glacio-isosta tic uplift of the order of 22-25 m. (C) 2000 Elsevier Science Ltd. All righ ts reserved.