Palaeoenvironments in the Skagerrak‐Kattegat basin in the eastern North Sea during the last deglaciation

Abstract

The study of a c. 18 m thick Late Weichselian‐ Early Holocene (isotope stage 2/1) marine succession (original water depth 100–150 m) from the Skagen 3 borehole, northern Denmark, has led to a better understanding of the palaeoenvironmental changes during the last deglaciation. The palaeoenvironmental interpretation is based on benthic foraminifera, stable isotope composition and lithology, whereas the chronostratigraphy and sedimentation rates are based on AMS radiocarbon dates. Marine conditions were established in the area at between 15 000 and 14 500 BP (reservoir corrected 14C years), and the first influence of Atlantic water masses imported through the Norwegian Channel is registered from 13 100 BP to 10 900BP (the Bølling‐ Allerrad interstadial complex). This was followed by the Younger Dryas cooling event between 10 900 and 10 100 BP. The hydrographic change at the Pleistocene‐Holocene transition after the Younger Dryas occurred in two stages. Arctic/subarctic deep‐water assemblages persisted continuously at Skagen after the first stage at 10 200 BP, while cold boreal assemblages existed in shallower water environments in the Kattegat‐Skagerrak basin during the same period of time. The slight warming in the early Holocene seems to have been interrupted by a short‐term cooling at about 9700–9600 BP. Finally, at 9600 BP the arrival of warm Atlantic water masses created full‐interglacial conditions in the whole region.