1 - Lomonosov Moscow State University, Geographical Faculty, Moscow, Russia
2 - Texas A&M University, College Station, USA
3 - VNIIOkeangeologiya, St.Petersburg, Russia
4 - VSEGEI, St.Petersburg, Russia
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).
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Ссылка на статью:
Taldenkova E., Nikolaev S., Stepanova A., Gusev E., Rekant P., Chistyakova N., Novikhina E., Pyatkova M. A new Quaternary sediment sequence from the eastern Mendeleev Ridge: preliminary stratigraphic subdivision based on IRD and microfossil records // Terra Nostra 2015/1, Proceedings of the 3rd International Conference and Workshop Past Gateways. Potsdam, 2015. P. 78.