GreenICE sediment cores reveal reduced last Interglacial Arctic sea ice cover

We present a sediment record of the last ca. 200,000 years from the
southernmost part of the Lomonosov Ridge off the northern Greenland/Canada continental margin. Evident cyclic changes in hemipelagic sediment types and microfossil content reflect changing glacial-interglacial ice cover characteristics and shifting paleoceanographic circulation patterns. Increased input of coarse ice-rafted debris, from mainly northern Canada, appears to be related to glacial marine isotope stages 6, 4, and late 3. Interglacial stages 7, 5e, and 1, as well as warm interstadial 5a and mid stage 3 were characterised by deposition of
fine-grained sediment with abundant planktic foraminifera suggesting less severe ice conditions. The occurrence of abundant small (>63μm) subpolar Turborotalita quinqueloba in the intervals representing substages 5e (last interglacial) and 5a (warm interstadial) implies that last interglacial sea ice concentrations were considerably reduced off some areas of northern Greenland/Canada. Whether this was part of a larger regional pattern or it represents the influence of extensive polynya areas with locally increased primary productivity remains to be solved.