Sediment core KD12-03-10C (79°27,75’N, 171°55,08’W, 2200 m water depth) was retrieved in 2012 during Russian expedition aboard RV “Kapitan Dranitsyn”. The 575 cm long sediment sequence was analyzed for IRD (>500 microns), planktic and benthic foraminifers and ostracods (from >125 micron fraction) with 10 cm interval (the uppermost 30 cm were analyzed continuously).

Correlation of the obtained results with previously published evidence [Polyak et al., 2004, 2013; Cronin et al., 2008, 2013, 2014; Adler et al., 2009; Stein et al., 2010; Hanslik, 2011; Poirier et al., 2012] allowed for a preliminary stratigraphic subdivision of the sediment sequence.

The major stratigraphic markers recorded so far in the sediments are:

1) seven IRD peaks corresponding to the decay/ growth of continental ice sheets in the upper 445 cm; sediments below 445 cm almost devoid of IRD with rare microfossils signify conditions of seasonal sea-ice cover and high productivity prior to the onset of major glaciations;

2) first occurrence of rare dolomites in the oldest IRD peak (MIS16?) and growing representation of dolomites upcore up to 40-60% in pink layers 1 and 2 at 170-180 (MIS7/8?) and 75-80 (MIS 5d?) cm, respectively;

3) the oldest peak in the abundance of planktic foraminifers at 240-310 cm dominated by Turborotalita egelida (MIS11) correlative with the peak abundance of diverse benthic foraminifers including agglutinated species Cyclammina sp.;

4) faunal changes at 170-190 cm likely corresponding in age to MIS7-9 including disappearance of T. egelida and predominance of Neogloboquadrina pachyderma sin. among planktic foraminifers, appearance of Oridorsalis tener and the presence of indicative species Pullenia bulloides among benthic foraminifers;

5) occurrence of ostracod species Henryhowella asperrima in the limited depth interval 8-26 cm suggesting the age of MIS1-3 for this core interval.

This research was supported by the Russian Foundation for Basic Research (RFBR, project 15-05-08497).

References

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