Late-glacial and Holocene palaeoceanography of the North Icelandic shelf

High-resolution gravity cores and box cores from the North Icelandic shelf have been studied for palaeoceanographic history based on lithological and biostratigraphical foraminiferal data. Results from two outer shelf cores c overing the last 13.6 k C-14 yr BP are presented in this paper. The sedimen ts accumulated in north-south trending basins on each side of the Kolbeinse y Ridge at water depths of ca. 400 m. Sedimentation rates up to 1.5 m kyr(- 1) are observed during the Late-glacial and Holocene. The Vedde and Saksuna rvatn tephras are present in the cores as well as the Hekla 1104. A new tep hra, KOL-GS-2, has been identified and dated to 13.4 k C-14 yr BP, and anot her tephra, geochemically identical to the Borrobol Tephra, has been found at the same level. At present, the oceanographic Polar Front is located on the North Icelandic shelf, which experiences sharp oceanographic surface bo undaries between the cold East Icelandic Current and the warmer Irminger Cu rrent. Past changes in sedimentological and biological processes in the stu dy area are assumed to be related to fluctuations of the Polar Front. The a rea was deglaciated before ca. 14 kyr BP, but there is evidence of ice raft ing up to the end of the GS-1 (Greenland Stadial 1, Younger Dryas) period, increasing again towards the end of the Holocene. Foraminiferal studies sho w a relatively strong GS-2 (pre-13 kyr BP) palaeo-Irminger Current, followe d by severe cooling and then by unstable conditions during the remainder of the Gl-1 (Greenland Interstadial 1, Bolling-Allerod) and GS-1 (Younger Dry as). Another cooling event occurred during the Preboreal before the Holocen e current system was established at about 9 kyr BP. After a climatic optimu m between 9 and 6 kyr BP the climate began to deteriorate and fluctuate. Co pyright (C) 2000 John Wiley & Sons, Ltd.