Late Devensian ice‐marginal features in the central North Sea – processes and chronology

Palaeoglaciological reconstructions of the N orth S ea sector of the last B ritish I ce S heet have, as other shelf areas, suffered from a lack of dates directly related to ice‐front positions. In the present study new high‐resolution TOPAS seismic data, bathymetric records and sediment core data from the W itch G round B asin, central N orth S ea, were compiled. This compilation made it possible to map out three ice‐marginal positions, partly through identification of terminal moraines and partly through location of glacial‐fed debrisflows. The interfingering of the distal parts of the glacial‐fed debrisflows with continuous marine sedimentation enabled the development of a chronology for glacial events based on previously published and some new radiocarbon dates on marine molluscs and foraminifera. From these data it is suggested that after the central W itch G round B asin was deglaciated at c . 27 cal. ka BP , the eastern part was inundated by glacial ice from the east in the Tampen advance at c . 21 cal. ka BP . Subsequently, the basin was inundated by ice from northeast during the Fladen 1 ( c . 17.5 cal. ka BP ) and the F laden 2 (16.2 cal. ka BP ) events. It should be emphasized that the F laden 1 and 2 events, individually, may represent dynamics of relatively small lobes of glacial ice at the margin of the B ritish I ce S heet and that the climatic significance of these may be questioned. However, the F laden E vents probably correlate in time with the C logher H ead and K illard P oint re‐advances previously documented from I reland and the B remanger event from off western N orway, suggesting that the B ritish and F ennoscandian ice sheets both had major advances in their northwestern parts, close to the northwestern E uropean seaboard, at this time.