Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

Abstract

Abstract. Lake El'gygytgyn/NE Russia holds a continuous 3.58 Ma sediment record, which is regarded as the most longlasting climate archive of the terrestrial Arctic. Based on multi-proxy geochemical, mineralogical, and granulometric analyses of surface sediment, inlet stream and bedrock samples, supplemented by statistical methods, major processes influencing the modern sedimentation in the lake were investigated. Grain-size parameters and chemical elements linked to the input of feldspars from acidic bedrock indicate a windinduced two-cell current system as major driver of sediment transport and accumulation processes in Lake El'gygytgyn. The distribution of mafic rock related elements in the sediment on the lake floor can be traced back to the input of weathering products of basaltic rocks in the catchment. Obvious similarities in the spatial variability of manganese and heavy metals indicate sorption or co-precipitation of these elements with Fe and Mn hydroxides and oxides. But the similar distribution of organic matter and clay contents might also point to a fixation to organic components and clay minerals. An enrichment of mercury in the inlet streams might be indicative of neotectonic activity around the lake. The results of this study add to the fundamental knowledge of the modern lake processes of Lake El'gygytgyn and its lakecatchment interactions, and thus, yield crucial insights for the interpretation of paleo-data from this unique archive.

Inorganic geochemistry data from Lake El'gygytgyn sediments: marine isotope stages 6–11

“…The Ba/Sr ratios vary from 1.60 to 4.10 (mean 2.41, n = 302) during interglacial intervals and between 2.15 and 4.49 (mean 2.72, n = 292) in glacial sediments. The Ba and Rb content has a strong positive correlation with K 2 O (Table 1), which suggests a K-feldspar source for these elements (Wennrich et al, 2013a). (Fedo et al, 1995).…”

“…A decrease in the SiO 2 /Al 2 O 3 ratio can be related either to a decrease in grain size or a lower textural maturity (e.g., Weltje and von Eynatten, 2004). Von Eynatten et al (2012) point out that mechanical processes, such as comminution, impact sediment composition.…”

“…6), and a higher clay content, suggesting that Cr and Ni might be absorbed by either organic matter (e.g., Sharma et al, 2004) or clay minerals (e.g., Das and Haake, 2003;Pistolato et al, 2006). Geochemical analysis of surface sediments from the lake indicates that the main source of Cr and Ni is linked to weathering products of basalts and andesite basalts found along the southern shore of Lake El'gygytgyn (Wennrich et al, 2013a). …”

“…In general, the sediment data plots below the smectite-illite line with the lower position of data of warm stage sediments, suggesting that sediments of warm stages contain more feldspar. Enhanced concentrations of feldspar in the surface sediments of Lake El'gygytgyn are linked to their high coarse silt and sand contents (Wennrich et al, 2013a).…”

Dynamic diatom response to changing climate 0–1.2 Ma at Lake El'gygytgyn, Far East Russian Arctic

“…However, morphological evidence suggests higher and lower lake levels in the past, substantially impacting the area of shallow-water lake bottom (Fedorov et al, 2008;Juschus et al, 2011). Additional details of the modern setting and limnology are described elsewhere (Nolan and Brigham-Grette, 2007;Fedorov et al, 2012;Nolan, 2012;Nolan et al, 2012;Wennrich et al, 2013).…”