| ||
| ||
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).
References 1. R.E. Adler, L. Polyak L., K.A. Crawford et al. (2009). Sediment record from the western Arctic Ocean with an improved Late Quaternary age resolution: HOTRAX core HLY0503-8JPC, Mendeleev Ridge. Glob. Planet. Change, Vol. 68, p. 18-29. 2. T.M. Cronin, S.A. Smith, F. Eynaud et al. (2008). Quaternary paleoceanography of the central Arctic based on Integrated Ocean Drilling Program Arctic Coring Expedition 302 foraminiferal assemblages. Paleoceanography. Vol. 23, PAIS18, doi:10.1029/2007PA001484. 3. T.M. Cronin, L. Polyak, D. Reed et al. (2013). A 600-ka Arctic sea-ice record from Mendeleev Ridge based on ostracodes. Quat. Sci. Rev., Vol. 79, p. 157-167. 4. T.M. Cronin, L.H. DeNinno, L. Polyak et al. (2014). Quaternary ostracod and foraminiferal biostratigraphy and paleoceanography in the western Arctic Ocean. Marine Micropal., Vol. 111, p. 118-133. 5. D. Hanslik (2011). Late Quaternary biostratigraphy and paleoceanography of the central Arctic Ocean. PhD Thesis, Stockholm University. 6. R.K. Poirier, T.M. Cronin, W.M.Jr. Briggs, R. Lockwood (2012). Central Arctic paleoceanography for the last 50 kyr based on ostracode faunal assemblages. Mar. Micropal., Vol. 88-89, p. 65-76. 7. L. Polyak, W.B. Curry, D.A. Darby et al. (2004). Contrasting glacial/interglacial regimes in the western Arctic Ocean as exemplified by a sedimentary record from the Mendeleev Ridge. Palaeogeogr., Palaeoclim., Palaeoecol,. Vol. 203, p. 73-93. 8. L. Polyak, K.M. Best, K.A Crawford et al. (2013). Quaternary history of sea ice in the western Arctic Ocean based on foraminifera. Quat. Sci. Rev., Vol. 79, p. 145-156. 9. R. Stein, J. Matthiessen, F. Niessen et al. (2010). Towards a better (litho-)stratigraphy and reconstruction of Quaternary paleoenvironment in the Amerasian Basin (Arctic Ocean). Polarforschung, Vol. 79. p. 97-121.
|
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.
|