Pliocene to Pleistocene climate and environmental history of Lake El'gygytgyn, Far East Russian Arctic, based on high-resolution inorganic geochemistry data

Abstract

Abstract. The 3.6 Ma sediment record of Lake El'gygytgyn/NE Russia, Far East Russian Arctic, represents the longest continuous climate archive of the terrestrial Arctic. Its elemental composition as determined by X-ray fluorescence scanning exhibits significant changes since the mid-Pliocene caused by climate-driven variations in primary production, postdepositional diagenetic processes, and lake circulation as well as weathering processes in its catchment. During the mid- to late Pliocene, warmer and wetter climatic conditions are reflected by elevated Si / Ti ratios, indicating enhanced diatom production in the lake. Prior to 3.3 Ma, this signal is overprinted by intensified detrital input from the catchment, visible in maxima of clastic-related proxies, such as K. In addition, calcite formation in the early lake history points to enhanced Ca flux into the lake caused by intensified weathering in the catchment. A lack of calcite deposition after ca. 3.3 Ma is linked to the development of permafrost in the region triggered by cooling in the mid-Pliocene. After ca. 3.0 Ma the elemental data suggest a gradual transition to Pleistocene-style glacial–interglacial cyclicity. In the early Pleistocene, the cyclicity was first dominated by variations on the 41 kyr obliquity band but experienced a change to a 100 kyr eccentricity dominance during the middle Pleistocene transition (MPT) at ca. 1.2–0.6 Ma. This clearly demonstrates the sensitivity of the Lake El'gygytgyn record to orbital forcing. A successive decrease of the baseline levels of the redox-sensitive Mn / Fe ratio and magnetic susceptibility between 2.3 and 1.8 Ma reflects an overall change in the bottom-water oxygenation due to an intensified occurrence of pervasive glacial episodes in the early Pleistocene. The coincidence with major changes in the North Pacific and Bering Sea paleoceanography at ca. 1.8 Ma implies that the change in lake hydrology was caused by a regional cooling in the North Pacific and the western Beringian landmass and/or changes in the continentality. Further increases in total organic carbon and total nitrogen content after ca. 1.6 Ma are attributed to reduced organic matter decay in the sediment during prolonged anoxic periods. This points to more extensive periods of perennial ice coverage, and thus, to a progressive shifts towards more intense peak glacial periods. In the course of the Pleistocene glacial–interglacial sequence eight so-called "super-interglacials" occur. Their exceptionally warm conditions are reflected by extreme Si / Ti peaks accompanied by lows in Ti, K, and Fe, thus indicating extraordinary high lake productivity.

Deglaciation history of Lake Ladoga (northwestern Russia) based on varved sediments

“…They show internal fining upward patterns from bright sand or silt at the bottom, with sharp basal boundaries, towards dark grey clay layers at the top. Rb is frequently enriched in fine-grained clastic lake sediments, mainly due to its occurrence in clay minerals (Cuven et al 2010;Kylander et al 2011), and has repeatedly been used as a grain-size proxy in lake-sediment records (Kalugin et al 2007;Wennrich et al 2014). Furthermore, according to the core description and smear slide analyses, the sediment lacks macroscopic organic remains.…”

“…3). Rb is frequently enriched in fine-grained clastic lake sediments, mainly due to its occurrence in clay minerals (Cuven et al 2010;Kylander et al 2011), and has repeatedly been used as a grain-size proxy in lake-sediment records (Kalugin et al 2007;Wennrich et al 2014). EM 1 further shows a good correlation with the clay content, and the elements Fe, Rb, K and Ti show a similarly good correlation.…”

Sedimentological processes and environmental variability at Lake Ohrid (Macedonia, Albania) between 637 ka and the present

“…The global glacial-interglacial variability has widely been studied on ice cores (e.g., EPICA-members, 2004;NGRIPmembers, 2004) and on marine sediment successions (e.g., Lisiecki and Raymo, 2005). In terrestrial realms, long continuous paleoclimatic records are sparse and mostly restricted to loess-paleosol sequences (e.g., Chen et al, 1999), to speleothem records (Bar-Matthews and Ayalon, 2004;Wang et al, 2008), and to lacustrine sediments (e.g., Prokopenko et al, 2006;Melles et al, 2012). In the eastern and southeastern Mediterranean region, long terrestrial paleo-records have become available from Lake Van (Stockhecke et al, 2014a), the Dead Sea (Stein et al, 2011), and from the Soreq Cave speleothem record (Bar-Matthews and Ayalon, 2004).…”

High‐latitude vegetation and climate changes during the Mid‐Pleistocene Transition inferred from a palynological record from Lake El'gygytgyn, NE Russian Arctic

“…; Wennrich et al . , ). Amongst these studies, palynological analyses provide insights into the vegetation and climate history since the upper Pliocene (Lozhkin et al .…”

“…High-resolution multi-proxy studies of this core have provided invaluable insights into regional and global climatic response to changes in orbital forcing (e.g. Melles et al 2012;Brigham-Grette et al 2013;Francke et al 2013;Tarasov et al 2013;Andreev et al 2014;Wennrich et al 2014Wennrich et al , 2016. Amongst these studies, palynological analyses provide insights into the vegetation and climate history since the upper Pliocene (Lozhkin et al 2007;Andreev et al 2012Andreev et al , 2014Andreev et al , 2016Tarasov et al 2013;Zhao et al 2015).…”