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

Abstract

This paper focuses on the characterization and genesis of mass movement deposits (MMDs) in the Quaternary and Pliocene sediments of Lake El'gygytgyn, Far East Russian Arctic. Three partly overlapping holes were drilled into the 320 m long sediment record at International Continental Scientific Drilling Program (ICDP) Site 5011-1 in the lake basin, recovering the Quaternary almost completely, and the Pliocene down to 3.6 Ma with 52% recovery. Mass movement deposits were investigated in all three cores, based on macroscopical core descriptions, radiographic images, high-resolution magnetic susceptibility and gamma-ray density. Five different types of MMDs were identified: turbidites, grain-flow deposits, debrites, slumps and slides. These are formed by transitional mass movement processes, and thus can be co-generic. An initial slope failure is thought to transform into a debris flow that deforms frontal sediments, partly disintegrates and dilutes into a turbidity flow. Turbidites are by far the most frequent MMD type in the lake center. They occur throughout the record in all pelagic sedimentary facies, but they are thinner in facies formed during cold climate conditions. All other MMDs, by contrast, incise exclusively the pelagic facies deposited during warm climates. In the 123 m thick Quaternary composite sediment record 230 mass movement events are identified, comprising 33% of the sediment length. Turbidites contribute 93% of the number of Quaternary MMDs, but only 35% of their thickness. In the Pliocene sediments between 123 and 320 m, 181 additional mass movement deposits are identified, which constitute ~33% of the recovered sediments. The mean recurrence interval for MMDs is 11 and 5 ka in the Quaternary and Pliocene, respectively

Response of fluvial, aeolian, and lacustrine systems to late Pleistocene to Holocene climate change, Lower Moravian Basin, Czech Republic

“…Although an exactly analogous example was not found in the literature, component aspects are well documented. Lacustrine turbidites are well known (e.g., Houbolt and Jonker, 1968;Lara and Sanders, 1970), including those in glacial or periglacial environments (e.g., Church and Gilbert, 1975;Gruszka, 2007;Sauerbrey et al, 2013). Examples of dunedamming of fluvial channels include those from the Pleistocene and Holocene Nebraska Sands Hills (Loope et al, 1995;Muhs et al, 2000) and the Holocene of the Lake Superior area (Loope et al, 2004).…”

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

“…EM 3 represents particularly coarse-grained sandy sediments, which occur in the basal parts of particularly thick and coarse-grained varves. These layers are interpreted as grain-flow deposits, which originate from failure of well-sorted, sandy sediments, such as those occurring in lake deltas (Sauerbrey et al 2013). Amongst those events are the basal parts of graded turbidites, which are formed by successive deposition from poorly sorted turbidity currents that originate from slope failures (Shaw 1977;Cuven et al 2010;Sauerbrey et al 2013).…”

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

“…Turbidity currents, whose deposits are typically characterized by graded bedding of the sediments with a coarse base and a fine silt/clay cap, are rather abundant in older sediments of Lake El'gygytgyn but have not been observed for the last 3200 uncal. 14 C years (Juschus et al, 2009;Sauerbrey et al, 2013). The lack of the typical structure in the modern sediments along the coarse tongue also rules out an origin from turbidity currents.…”