MIS4 AND MIS3 IN NW EUROPE: NORTH SEA BASIN AND THE RIVER RHINE BETWEEN SCANDINAVIAN ICE FRONT AND ATLANTIC SHELF EDGE

The epi-continental North Sea Basin in NW Europe contains a well developed and diverse sedimentary record of the last glacial, that sits in a critical position between Scandinavian and British ice caps (N) and the Atlantic shelf edge (SW), to which it connects via the English Channel. The north has subglacial and glacio-marine deposits, ranging in age from MIS4 to MIS2. The south has widespread sandy fluvial deposition, burying and dissecting shallow marine and deltaic deposits from MIS5.

Below the modern Rhine delta (Netherlands) lays the area with greatest age control, obtained through combined OSL-sampling and fluvial-architecture mapping strategies. Inherited conditions of basin fill and deglaciation topography ([1] MIS6 and older) echo through in the architecture, on which MIS4-3-2 glacio-isostasy and climatologically induced fluvial style changes had clear overprint [2]. Offshore towards the Strait of Dover in the SW, dissection dominates. In this key area potential MIS4-3-2 ice-marginal rivers joined the rivers Rhine and Thames on their way south. Important new steps to resolve this area have now been made [3], by linking patches of deposits to the more complete onshore Rhine record, and by tracing nested incisive features downstream towards Channel River in the south. Both in the offshore and onshore of the southern North Sea basin, the geology clearly resolves MIS4‑3 as an important period of record-leaving time: as geomorphology and as deposits.

The south of the basin allows tracing young dissective features upstream towards British and Scandinavian ice periphery in the north. This links OSL-dated MIS4-3-2 fluvial records, to non-dated Last Glacial offshore tills and glacio-marine sediment from at or beyond the ¹⁴C-method limit (problematic >30,000 ¹⁴C years in our particular setting). That exercise raises questions on age attribution of glacial limit features such as the Dogger bank (central North Sea), which with current data might just as well be a MIS4 feature (our preference) as a MIS3/2 feature (often presumed). This is also of importance for climatological and sedimentary interpretation of marine records from along the Atlantic shelf edge, both south and north of the British Isles.

References

1 Busschers et al., 2008 Boreas

2 Busschers et al., 2007 QSR

3 Hijma et al., forthcoming, JQS