Middle to Late Pleistocene lake‐level fluctuations of Lake El'gygytgyn, far‐east Russian Arctic

Abstract

Lake El'gygytgyn, located in central Chukotka, Russian Arctic, was the subject of an international drilling project that resulted in the recovery of the longest continuous palaeoclimatic and palaeoenvironmental record for the terrestrial Arctic covering the last 3.6 million years. Here, we present the reconstruction of the lake-level fluctuations of Lake El'gygytgyn since Marine Isotope Stage (MIS) 7 based on lithological and palynological as well as chronological studies of shallow-water sediment cores and subaerial lake terraces. Reconstructed lake levels show an abrupt rise during glacial-interglacial terminations (MIS 6/5 and MIS 2/1) and during the MIS 4/3 stadial-interstadial transition. The most prominent lowstands occurred during glacial periods associated with a permanent lake-ice cover (namely MIS 6, MIS 4 and MIS 2). Major triggering mechanisms of the lake-level fluctuations at Lake El'gygytgyn are predominantly changes in air temperature and precipitation. Regional summer temperatures control the volume of meltwater supply as well as the duration of the lake-ice cover (permanent or seasonal). The duration of the lake-ice cover, in turn, enables or hampers near-shore sediment transport, thus leading to long-term lake-level oscillations on glacial-interglacial time scales by blocking or opening the lake outflow, respectively. During periods of seasonal ice cover the lake level was additionally influenced by changes in precipitation. The discovered mechanism of climatologically driven level fluctuations of Lake El'gygytgyn are probably valid for large hydrologically open lakes in the Arctic in general, thus helping to understand arctic palaeohydrology and providing missing information for climate modelling.

Lateglacial and Holocene palaeoenvironments on Bolshevik Island (Severnaya Zemlya), Russian High Arctic

“…2) may be explained by some wave actions and wind-induced currents in partly open water, leading to zero sedimentation or even minor erosion in the upper part of Unit A. Comparable (low) sedimentation rates have been discovered in the other arctic lakes (Fedorov et al 2019).…”

“…Comparable (low) sedimentation rates have been discovered in the other arctic lakes (Fedorov et al . ).…”

Geochemical and sedimentological responses of Arctic glacial Lake Ilirney, Chukotka (Far East Russia) to palaeoenvironmental change since ~ 51.8 ka BP

“…Abundant planktonic diatoms led to low benthic/ planktonic diatom ratios throughout LUIV implying high lake levels during this time with limited habitat availability for benthic taxa (Heinsalu et al, 2007;Wang et al, 2011;Wolin and Stone, 2010). Lake-level reconstructions from El'gygytgyn have been used to imply that lake levels were high following MIS4 leading to the formation of a lacustrine terrace 9e11 m above the current lakelevel (Fedorov et al, 2019;Glushkova and Smirnov, 2007). Though the timing of the lake highestand was not effectively constrained due to the lack of a reliable age model at El'gygytgyn, high lake levels represented favourable conditions that occurred during MIS3 (Juschus et al, 2011).…”

“…Evidence for lake-level variability during the Holocene is seen by erosional truncation of acoustic reflectors belonging to AU2 and the pinching out of AU1 reflectors at water depths <10 m. The occasional absence of AU1 in the shallow outflow area is evidence of subaerial exposure of older sediments with subsequent erosion. Evidence from El'gygytgyn has suggested that lake levels during the Holocene were initially high but decreased progressively (Fedorov et al, 2019;Glushkova and Smirnov, 2007;Juschus et al, 2011). Recent lake-level variability is evidenced by the absence of significant deposition of AU1 on top of sediments in shallow areas.…”

Northern Eurasian lakes – late Quaternary glaciation and climate history – introduction

“…Fedorov et al . () reconstructed the lake‐level fluctuations of Lake El'gygytgyn since MIS 7, using lithological and palynological as well as chronological data of shallow‐water sediment cores and subaerial lake terraces. The results suggest that the main triggers of lake‐level fluctuations are changes in air temperature and precipitation, with the former controlling the duration of the lake‐ice cover and the associated near‐shore sediment transport that blocks or opens the outflow.…”