Dinoflagellate cyst evidence for warm interglacial conditions at the northern Barents Sea margin during marine oxygen isotope stage 5

Dinoflagellate cyst analysis has been conducted on a sediment core from the northern Barents Sea margin (eastern Arctic Ocean) to reconstruct sea-surf ace conditions during marine oxygen isotope stage 5. Cyst concentrations an d composition of assemblages display a distinct variability reflecting degl acial warming and the onset of relatively warm interglacial conditions in e arly stage 5. Dinoflagellate cyst assemblages of the last interglacial, whi ch corresponds broadly to substage 5e, are comparable with those from recen t sediments of the area, but have lower abundances of cold water taxa. Such assemblages suggest that sea-surface temperatures of the last interglacial were therefore at least as warm as today or even warmer. After a distinct cooling, relatively stable cold conditions with minor periods of surface wa ter warming prevailed from mid-substages 5d to 5b. Temperatures might have been similar in substages 5a and 5e, but the different compositions of asse mblages indicate a stronger stratification of surface waters, probably owin g to a larger meltwater supply, in substage 5a. These results are compared with previous studies on marine carbonate and calcareous microfossil record s from the Fram Strait and Yermak Plateau area, which show that the general view of a cold last interglacial in the eastern Arctic Ocean is untenable. Copyright (C) 2001 John Wiley & Sons, Ltd.