Samenvatting van de lezing op 8 januari 2000 The Quaternary Geology of East Anglia

The Red Crag Formation (Pre-Ludhamian to Thumian, tentatively Praetiglian to Tiglian B) was deposited in structurally-controlled basins. Afteraregression, it is followed unconformably by the Norwich Crag Formation (Antian/ Bramertonian to Baventian, tentatively Tiglian Cl to C4c). A regression during the Baventian led to the formation of shoreface gravels (Westleton Beds) and intertidal clays (Baston Bavents Clay) at the mouth of the Bytham River which flowed front the English Midlands. The Chillesford Clay was similarly formed at the mouth of the proto-Thames. Sands and gravels in north-eastem Suffolk and eastem Norfolk, characterised by the inclusion of pebbles of quartz, quartzite and Welsh volcanic rocks, have previously been considered deposits of the proto-Thames (Kesgrave Formation). However we now know these to be largely marine, and a new formation, the Wroxham Crag, has been set up within the Crag Group. This includes the Bure Valley Beds and Weyboume Crag of earlier authors, and is of Pre-Pastonian to Pastonian age. The transgressions at the bases of the Red, Norwich and Wroxham Crag formations are tentatively correlated with reflectors at the base of the Westkapelle Ground, Smith’s Knoll and Winterton Shoal formations of the southem North Sea.