ALBERT

Beschreibung: Two ultra-high resolution IMAGES sediment cores from the SW continental slope of the Barents Sea and the Vøring Plateau are used to reconstruct fluctuations of a Barents Sea ice sheet with respect to variations in flow intensity and direction of the Norwegian Current during the last glacial-to-interglacial cycle (〉 40 - 6.6 14C kyr BP equal to 45 - 7.5 cal. kyr BP). Detailed planktic AMS 14C records from both locations reveal a strong tendency towards higher ages during periods of intense meltwater and/or glacial activity on the Barents shelf. Ages in the core from the continental slope are heavily influenced by reworked 14C-free foraminiferal tests from the Barents shelf. Reworked foraminiferal accumulation rates were quantified by tuning the planktic d18O profile to the GISP2 d18O ice core record. In conjunction with the ice-rafted detritus record, this new proxy shows that ice reached the shelf edge at least twice during the mid-Weichselian and was used to develop a new glaciation curve for the SW Barents Sea. Ice sheet growth and decay on the Barents shelf was sensitive to variations in the intensity of the Norwegian Current, which ultimately lead to the final break-up of the Barents Sea ice sheet at the end of the last glacial maximum. A general analogy for major meltwater episodes is found in Heinrich Event 1 (H1): a strong inflow of Atlantic water, documented by a rapid rise in planktic d13C values, followed by the actual meltwater discharge, represented by pronounced d18O/d13C minima and massive ice-rafted detritus and reworked foraminiferal carbonate input. On the Vuring Plateau, 14C ages measured at the onset of HI were probably biased by an increased inflow and up-welling of 'old' North Atlantic Intermediate Water resulting from a reversal of the Norwegian Current in response to massive meltwater input from the Barents Sea. The younger 14C ages marking H1 in the Norwegian Sea suggest a delayed Barents Sea meltwater discharge of up to 1500 years with respect to the Laurentide H1 signal in the open N. Atlantic.