History of the North Polar Seas During the Past 5 Million Years

Abstract

For many years we did not have any opportunity to investigate the late Cenozoic palaeoclimatic history of the Arctic Ocean per se because it was impossible to collect suitable sample material. Early sampling efforts have been carried out by F. Nansen, but long sediment cores which allow palaeoclimatic and palaeo-oceanographic studies have only been collected in the sixties from the ice island T3 (Hunkins et al., 1971). In the meantime these sample collections have been supplemented by Canandian, U.S., Norwegian, Swedish and Soviet expeditions and numerous sediment cores are available for stratigraphic studies (Clark et al., 1980, Boshöm 8 Thiede, 1981). However, it has been shown that the present cores comprise (Fig. 1) only of upper Cenozoic deposits (Pleio-Pleistocene, possibly a bit of uppermost Miocene) except two short core segments with older tuffaceous and siliceous muds which are found displaced into Pleisticene sediments. The two older core segments are of Palaeocene and late Cretaceous age, and both of them indicate a temperate climatic regime. As the oldest Neogene sediments from the Arctic Ocean already contain ice-rafted coarse terrigenous debris the important processes during the initiation and early stages of Northern Hemisphere cooling and glaciation cannot be reconstructed at all.