Multivariate statistic and time series analyses of grain-size data in Quaternary sediments of Lake El'gygytgyn, NE Russia

Abstract

Lake El'gygytgyn, located in the Far East Russian Arctic, was formed by a meteorite impact about 3.58 Ma ago. In 2009, the ICDP Lake El'gygytgyn Drilling Project obtained a continuous sediment sequence of the lacustrine deposits and the upper part of the impact breccia. Here, we present grain-size data of the past 2.6 Ma. General downcore grain-size variations yield coarser sediments during warm periods and finer ones during cold periods. According to Principal Component Analyses (PCA), the climate-dependent variations in grain-size distributions mainly occur in the coarse silt and very fine silt fraction. During interglacial periods, accumulation of coarser grain sizes in the lake center is supposed to be caused by redistribution of clastic material by a wind-induced current pattern during the ice-free period. Sediment supply to the lake is triggered by the thickness of the active layer in the catchment, and the availability of water as transport medium. During glacial periods, sedimentation at Lake El'gygytgyn is hampered by the occurrence of a perennial ice-cover with sedimentation being restricted to seasonal moats and vertical conducts through the ice. Thus, the summer temperature predominantly triggers transport of coarse material into the lake center. Time series analysis that was carried out to gain insight in the frequency of the grain-size data showed grain-size variations predominately on Milankovitch's eccentricity, obliquity and precession bands. Variations in the relative power of these three oscillation bands during the Quaternary imply that climate conditions at Lake El'gygytgyn are mainly triggered by global glacial/interglacial variations (eccentricity, obliquity) and local insolation forcing (precession), respectively

Mass movement deposits in the 3.6 Ma sediment record of Lake El'gygytgyn, Far East Russian Arctic

“…Considerable lake-level rises may breach the lagoons, thus transporting coarse-grained material into the lake that may result in mass movement processes . Aeolian transport, in contrast, has not been very significant in present conditions or during the Quaternary Francke et al, 2013).…”

Detailed insight into Arctic climatic variability during MIS 11c at Lake El'gygytgyn, NE Russia

“…Probably as a result of its transitional character between lithofacies A and C, commonly occurring greenish bands described as a distinct feature of lithofacies B by Melles et al (2012) are lacking. The grain size distribution is dominated by silt (68-71 vol%) and clay (25-28 vol%) with minor concentrations of sand-sized particles (2-5 vol%; Francke et al, 2013). TOC concentrations of 0.5-1 %, BSi concentrations of 15-30 %, a TOC/TN ratio of 5-10, Ti count rates between 700-1300, and a Mn/Fe ratio of 10-15 are further characteristics of lithofacies B (Fig.…”

“…Because the core interval investigated here comprises transitions to lithofacies B, clastic laminations are rather weakly expressed and are intercalated with more homogenous light gray to brown intervals (17.97-17.94, 19.34-19.32, 19.56-19.45 mblf), which we assigned for this paper to lithofacies A. Laminae, when present, are characterized by upward grading from silt to clay. The grain size distribution is dominated by silt (68-70 vol%) and clay (25-31 vol%) with minor concentrations of sand-sized particles (0.5-5 vol%; Francke et al, 2013). TOC concentrations < 1 %, BSi concentrations < 15 %, a TOC/TN ratio of 5-10, Ti count rates between 1000-2100, and a Mn/Fe ratio of < 10 are further characteristics of lithofacies A (Fig.…”

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

“…Prior to the measurement, samples were pretreated according to Francke et al (2013) to remove organic matter (30 % H 2 O 2 , 50 • C, 18 h), vivianite nodules (0.5 M HNO 3 , 50 • C, 5 h, 30 min shaking in between) and biogenic silica (0.5 M NaOH leaching, 90 • C, 2 × 30 min.). The results of the treatment steps were validated by biogeochemical analyses, Fourier Transform Infrared Spectroscopy (FTIRS), XRD, scanning electron microscopy (SEM) and optical microscopic investigations .…”