Genesis and palaeogeographical significance of the Corton Diamicton (basalmember of the North Sea Drift Formation), East Anglia, UK

The Corton Diamicton, the lower diamicton unit of the Anglian-age North Sea Drift Formation is investigated at two coastal localities in East Anglia - Trimingham and Corton. At Trimingham, the diamicton was deposited subglaci ally by Scandinavian ice which entered the region of north Norfolk from the northeast. The deposit consists of a three-tiered till assemblage characte ristic of constructional glaciotectonic deformation: a lower tectonite cons isting of deformed local preglacial sands; a middle till deformed by brittl e shear; and an upper massive till deformed by ductile deformation. At Cort on, the diamicton was deposited as part of a prograding grounding line fan which formed as a point-source depocentre adjacent to the temporary, subaqu eous grounded margin of the Scandinavian ice sheet. The study contributes t o an understanding of early Anglian palaeogeography by demonstrating the in fluence of grounded ice on drainage within the Bytham catchment, and the de velopment of an extensive proglacial lake basin within the region.