Sediment cores from a borehole penetrating the upper flat-lying reflectors (ca. 200 m) above the angular unconformity in the Norwegian Channel off western Norway have been investigated. Lithological, biostratigraphical (foraminifera) and geochronological (14C, amino acid, strontium isotopes and palaeomagnetism) analyses, combined with shallow seismic data from the region, have been used to interpret the Quatemary depositional history of the Norwegian Channel. Three thick and extensive till imits, each with sharp, erosional lower boundaries are interbedded with marine sediments. The o ldest till unit (representing the Fedje Glaciation) is situated directly on top of the angular unconformity and suggests glacial erosion as the major process in the formation of the Norwegian Channel. The age of this till unit is ca. 1,1 Ma. Above this unit follows a ca. 50-m thick marine unit deposited between 1,1 Ma and ca. 0.6 Ma. A warm phase with conditions close to the present ones (the Radøy Interglacial) is recorded in the lower part of this unit, suggesting a strong advection of Atlantic water into the Norwegian Sea region. Following a relatively cool interval, a further warm period (the Norwegian Trench lnterglacial) is recorded a bove the Brunhes/Matuyama boundary (0.7 Ma). Above this follows a till unit of Middle P leistocene age. Between this and a Weichselian till, a pocket of more sorted material is identified at the Troll Field. Within this pocket, sediments of last interglacial age have been recorded in a neighbouring core. The ca. 50 m thick till unit above this represents at least two phases of glaciation during the Weichselian. The last deglaciation occurred at 15 ka. The Troll Field record suggests that some of the Middle and Early Pleistocene climatic oscillations attained amplitudes compara ble with those recorded for the Late Quatemary in this region. However, during the period between ca. 1.1 and ca. 0.6 Ma the Fennoscandian ice sheet did not expand out on to the shelf.
Quaternary of the Norwegian Channel: glaciation history and palaeoceanography