Middle Pleistocene sedimentology and lithostratigraphy of Weybourne northeast Norfolk, England

Abstract

This paper investigates pre-glacial and glacial deposits exposed in coastal cliff sections of the Weybourne area, northeast Norfolk. At this site, shallow-marine sediments of the early Middle Pleistocene Wroxham Crag Formation are overlain by two glaciotectonized and interbedded tills and glaciofluvial sands and gravels of Middle Pleistocene age. The lower sandy Runton Till (Third Cromer Till) is tectonized and incorporated into the overlying chalk-rich till forming the banded Weybourne Town Till (Marly Drift). Structures within these tills indicate that they were deposited subglacially and the two till lithologies were intermixed as the water-saturated Runton Till was remoulded and assimilated within the banded and chalk-rich Weybourne Town Till. Although the Runton Till has been traditionally attributed to deposition by a Scandinavian-based ice sheet, clast lithologies indicate that both the Runton and Weybourne Town tills were deposited by a Scottish-based ice-advance that moved down the coast of eastern England. The overlying sand and gravel succession, preserved only in large synform ‘sag-basins’ is interpreted as glacial outwash on the basis of its sedimentology and clast lithology, and is correlated with the Briton's Lane Sand and Gravel by the presence of a Scandinavian clast component.