A 250 ka oxygen isotope record from diatoms at Lake El'gygytgyn, far east Russian Arctic

Abstract

In 2003 sediment core Lz1024 was drilled at Lake El'gygytgyn, far east Russian Arctic, in an area of the Northern Hemisphere which has not been glaciated for the last 3.6 Ma. Biogenic silica was used for analysing the oxygen isotope composition (&delta;¹⁸O_diatom) in the upper 13 m long section dating back about 250 ka with samples dominated by one taxa in the <10 &mu;m fraction (<i>Cyclotella ocellata</i>). Downcore variations in &delta;¹⁸O values show that glacial-interglacial cycles are present throughout the core and &delta;¹⁸O_diatom-values are mainly controlled by &delta;¹⁸O_{precipitation}. Changes reflect the Holocene Thermal Maximum, the Last Glacial Maximum (LGM) and the interglacial periods corresponding to MIS 5.5 and MIS 7 with a peak-to-peak amplitude between LGM and MIS 5.5 of &Delta;¹⁸O = 5.3&permil;. This corresponds to a mean annual air temperature difference of about 9 °C. Our record is the first continuous &delta;¹⁸O_diatom record from an Arctic lake sediment core directly responding to precipitation and dating back more than 250 ka and correlates well with the stacked marine &delta;¹⁸O LR04 (<i>r</i> = 0.58) and &delta;D EPICA Dome-C record (<i>r</i> = 0.69). With &delta;¹⁸O results indicating strong links to both marine and ice-core records, records from Lake El'gygytgyn can be used to further investigate the sensitivity of the Arctic climate to both past and future global climatic changes.