Abstract
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 (δ18Odiatom) in the upper 13 m long section dating back about 250 ka with samples dominated by one taxa in the <10 μm fraction (Cyclotella ocellata). Downcore variations in δ18O values show that glacial-interglacial cycles are present throughout the core and δ18Odiatom-values are mainly controlled by δ18Oprecipitation. 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 Δ18O = 5.3‰. This corresponds to a mean annual air temperature difference of about 9 °C. Our record is the first continuous δ18Odiatom 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 δ18O LR04 (r = 0.58) and δD EPICA Dome-C record (r = 0.69). With δ18O 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.
Highlights
1.1 The Arctic as an important area for paleoclimate reconstructionThe Arctic experienced the most rapid warming in the last 150 yr (Serreze et al, 2000; Kaufman et al, 2009; Bekryaev et al, 2010) with a continuation of this temperature trend above the global average projected for the 21st century (Serreze et al, 2000; Anisimov et al, 2007)
In an attempt to obtain an isotope record dominated by a single taxa, the < 10 μm fraction was purified according to an 8-step method developed by Chapligin et al (2012) which is similar to the 4-step method (Morley et al, 2004)
Five different types of diatoms and particles were counted for 40 samples downcore (Cyclotella ocellata, Pliocaenicus seczkinae, Surirella fragments, contamination particles and other diatom species) with an average of 236 ± 57 counts
Summary
1.1 The Arctic as an important area for paleoclimate reconstructionThe Arctic experienced the most rapid warming in the last 150 yr (Serreze et al, 2000; Kaufman et al, 2009; Bekryaev et al, 2010) with a continuation of this temperature trend above the global average projected for the 21st century (Serreze et al, 2000; Anisimov et al, 2007). In climate-sensitive areas such as the Arctic (Serreze and Francis, 2006a, b; Miller et al, 2010; Serreze and Barry, 2011), longer, continuous terrestrial records for paleo-climate reconstructions are rare (Brigham-Grette et al, 2007; CCSP, 2009) due to the coverage of large areas by glaciers, e.g. during the Last Glacial Maximum (LGM) (Dyke and Prest, 1987; Lehman et al, 1991; Thiede, 2004), which destroyed sedimentary sequences in lakes especially in the western part of Siberia (Svendsen et al, 1999; Hubberten et al, 2004). In an attempt to obtain Quaternary lake records from the terrestrial, far east Russian Arctic drilling campaigns were conducted at Lake El’gygytgyn in an area of the Northern Hemisphere which has not been glaciated during at least the last five glacial/interglacial cycles and has the potential to be an archive of continuous and undisturbed sedimentation (Brigham-Grette et al, 2007; Melles et al, 2007)
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