Impactite generation in the El’gygytgyn depression, northeast Russia, as a volcanic phenomenon. 2. On the petrography and geochemistry of the impactites

Belyi, V. F.

doi:10.1134/s0742046310030012

Cited by 9 publications

(6 citation statements)

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“…22.8 %; Fig. 2e , in both the acid and andesitic volcanic rocks (Gurov et al, 2005;Belyi, 2010). The clay mineral assemblage is composed of illite, smectite, chlorite, mixed layer clay minerals, and to a minor amount, kaolinite (Table 1), which concurs with earlier downcore clay mineral analyses from Lake El'gygytgyn (Asikainen et al, 2007).…”

Section: Bulk Mineralogysupporting

confidence: 76%

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

et al. 2013

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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.

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Section: Bulk Mineralogysupporting

confidence: 76%

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

et al. 2013

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“…All these lithologies are present in the target (Stone et al. ; Belyi ). In between lithic fragments, highly vesiculated melt clasts were observed (Fig.…”

Section: Resultsmentioning

confidence: 99%

Petrography of impact glasses and melt breccias from the El'gygytgyn impact structure, Russia

Pittarello

Koeberl

2013

Meteorit & Planetary Scien

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Abstract-The El'gygytgyn impact structure, 18 km in diameter and 3.6 Ma old, in Arctic Siberia, Russia, is the only impact structure on Earth mostly excavated in acidic volcanic rocks. The Late Cretaceous volcanic target includes lavas, tuffs, and ignimbrites of rhyolitic, dacitic, and andesitic composition, and local occurrence of basalt. Although the ejecta blanket around the crater is nearly completely eroded, bomb-shaped impact glasses, redeposited after the impact event, occur in lacustrine terraces within the crater. Here we present detailed petrographic descriptions of newly collected impact glass-bearing samples. The observed features contribute to constrain the formation of the melt and its cooling history within the framework of the impact process. The collected samples can be grouped into two types, characterized by specific features: (1) "pure" glasses, containing very few clasts or new crystals and which were likely formed during the early stages of cratering and (2) a second type, which represents composite samples with impact melt breccia lenses embedded in silicate glass. These mixed samples probably resulted from inclusion of unmelted impact debris during ejection and deposition. After deposition the glassy portions continued to deform, whereas the impact melt breccia inclusions that probably had already cooled down behaved as rigid bodies in the flow.

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“…3). Potassium in the Lake El'gygytgyn sediments partly derives from orthoclase (KAlSi 3 O 8 ), which abundantly occurs as phenocrysts in both rhyolitic and andesitic volcanic rocks of the lake catchment (Belyi, 2010;Gurov et al, 2005). Bulk mineral analyses of modern lake sediments and bedrock samples yielded orthoclase contents of up to 8.4 and 10.4 %, respectively (Wennrich et al, 2013).…”

Section: Simentioning

confidence: 99%

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

et al. 2014

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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.

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Impactite generation in the El’gygytgyn depression, northeast Russia, as a volcanic phenomenon. 2. On the petrography and geochemistry of the impactites

Cited by 9 publications

References 0 publications

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

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

Petrography of impact glasses and melt breccias from the El'gygytgyn impact structure, Russia

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

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