Two cores from the southwestern shelf and slope of Storfjorden, Svalbard, taken at 389 m and 1485 m water depth have been analyzed for benthic and planktic foraminifera, oxygen isotopes, and ice-rafted debris. The results show that over the last 20,000 yr, Atlantic water has been continuously present on the southwestern Svalbard shelf. However, from 15,000 to 10,000 14C yr BP, comprising the Heinrich event H1 interval, the Bølling–Allerød interstades and the Younger Dryas stade, it flowed as a subsurface water mass below a layer of polar surface water. In the benthic environment, the shift to interglacial conditions occurred at 10,000 14C yr BP. Due to the presence of a thin upper layer of polar water, surface conditions remained cold until ca. 9000 14C yr BP, when the warm Atlantic water finally appeared at the surface. Neither extensive sea ice cover nor large inputs of meltwater stopped the inflow of Atlantic water. Its warm core was merely submerged below the cold polar surface water.

[1] The Svalbard archipelago is located in the high Arctic (76°-80°N) within the northernmost reach of the West Spitsbergen Current, which is the continuation of the North Atlantic Current. In this specific setting close to the Polar Front, even small variations in the current system are expected to give large and distinct signals in paleoceanographic parameters. Thus the Svalbard area is ideal for monitoring the past history of the inflow of Atlantic water to the Arctic Ocean. We have studied sediment core NP94-51 taken outside the mouth of the Hinlopen Strait on the northern Svalbard shelf. The paleoceanographic development of the last deglaciation and the Holocene has been reconstructed using benthic and planktonic foraminifera, oxygen isotopes, and ice-rafted detritus. The results show that the first strong subsurface inflow of Atlantic water to the Arctic Ocean after the Last Glacial Maximum commenced at 12.6 14 C kyr B.P. (circa 15,000 calendar (cal) years B.P.) during the Bølling-Allerød interstadial. During the Younger Dryas, polar conditions prevailed at the surface with extensive sea ice cover, and the inflow of Atlantic-derived water was generally diminished. The inflow of more saline, but still cold Atlantic water was relatively strong during the early Holocene and caused intensified seasonal biological productivity. The Atlantic water inflow declined gradually during the mid-Holocene. Between 4500 and 1100 cal years B.P. the inflow was very weak, and the bottom waters over the northern Svalbard margin were cold and of lower salinity. During the last $1000 years, climatic conditions improved such that the subsurface inflow of Atlantic-derived water increased. However, the surface waters were still cold.