FLUCTUATIONS OF THE WEICHSELIAN ICE-SHEET IN SW ICELAND - A GLACIOMARINE SEQUENCE FROM SUDURNES, SELTJARNARNES

Sedimentological and palaeontological studies in Reykjavik, SW Iceland , show that the glaciation history during the Late Pleistocene was cha racterized by a fluctuating glacier flowing WNW from Reykjanes Peninsu la. New C-14 dates show that marine deposition took place in coastal r egions during at least three interstadials, corresponding to the Alesu nd, the Bolling, and the Allerod in Scandinavia. The oldest of these i nterstadials is dated to ca. 28,000 C-14 years BP and represents the o ldest Weichselian interstadial registered in Iceland up to now. Recent studies in Gardabaer, SW Iceland, show marine transgression during th e Bolling. Earlier work in Fossvogur, Reykjavik, indicates that the Al lerod-Younger Dryas boundary did not coincide with a marked change in the water masses in SW Iceland. Sedimentological studies reveal a rela tively high energy environment with near-shore and glaciomarine deposi tion and a period of glacial expansion during the Younger Dryas. The m acrofauna, foraminifera, and ostracod faunas from sediments dated to t he late Younger Dryas on Sudurnes have been analysed and indicate low arctic to high boreal conditions. The Sudurnes data show that the Youn ger Dryas glaciation in the Reykjavik area took place in a glaciomarin e environment. The youngest dated sediments of the Sudurnes sequence p robably postdate this glacier expansion. (C) 1997 Elsevier Science Ltd .