HOLOCENE PALEOCEANOGRAPHY AND PALEOENVIRONMENTS OF THE SKAGERRAK-KATTEGAT, SCANDINAVIA

Paleoceanographic and paleoenvironmental interpretations based on fora minifera, sedimentary data, radiocarbon dates, and stable isotope meas urements were derived from two sections in the Skagerrak: a 115-m-thic k Holocene marine section drilled onshore at Skagen near the northernm ost tip of Jutland, Denmark, and a 9-m piston core from the Skagerrak, north of Skagen. The foraminiferal data show that arctic-subarctic en vironments in the deep Skagerrak-Kattegat area were succeeded by borea l conditions at 9.6 ka. This was a result of northward migration of th e Atlantic polar front and inflow of warm Atlantic water into the area through the Norwegian Channel. A gradual warming of the water masses after 9.6 ka is indicated by the data. Rare foraminifera and high sedi mentation rates are found between approximately 8.6 ka and 7.6 ka at b oth core locations. The modem foraminiferal assemblages of the area we re fully established at 7.6 ka indicating that the modem circulation p attern in the Skagerrak-Kattegat after the opening of the English Chan nel and the Danish Straits was not established before this date. At 5. 5 ka a sudden change to coarser sediments (higher-energy environments) and the appearance of the foraminifer Eoeponidella laesoeensis is rec orded in the Skagen core. This indicates a rapid change in the hydrogr aphy reflecting altered meteorological and hydrographic conditions in the Skagerrak-Kattegat, including a strengthening of the Jutland Curre nt and increased inflow of North Sea water into the Kattegat. The even t is interpreted as a response to cooling at the end of the Holocene c limatic optimum in late Atlantic time and possibly reflects a rapid co oling event of North Atlantic surface water masses.