Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modelling

Mottaghy, Darius; Schwamborn, Georg; Rath, Volker

doi:10.5194/cpd-8-2607-2012

Cited by 4 publications

(2 citation statements)

References 49 publications

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“…The site is in the continuous permafrost zone (Yershov, 1998;Schwamborn et al, 2006Schwamborn et al, , 2008 with a MAAT (mean annual air temperature) of −10 • C at 3 m above the ground (Nolan and Brigham-Grette, 2007) and a MAGT (mean annual ground temperature) of −6.0 • C at 20 m depth (Motthagy et al, 2012). Permafrost thickness is estimated to be around 350 m based on borehole temperature measurements in hole 5011-3 (Mottaghy et al, 2012). Air temperature extremes in 2003 ranged from −40 • C to 26 • C. Precipitation comprised 70 mm summer rainfall (June-September) and 110 mm water equivalent of snow (Nolan and Brigham-Grette, 2007).…”

Section: Geographical Setting Of El'gygytgyn Cratermentioning

confidence: 99%

Depositional dynamics in the El'gygytgyn Crater margin: implications for the 3.6 Ma old sediment archive

Schwamborn¹,

Fedorov²,

Ostanin³

et al. 2012

Clim. Past

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Abstract. The combination of permafrost history and dynamics, lake level changes and the tectonical framework is considered to play a crucial role for sediment delivery to El'gygytgyn Crater Lake, NE Russian Arctic. The purpose of this study is to propose a depositional framework based on analyses of the core strata from the lake margin and historical reconstructions from various studies at the site. A sedimentological program has been conducted using frozen core samples from the 141.5 m long El'gygytgyn 5011-3 permafrost well. The drill site is located in sedimentary permafrost west of the lake that partly fills the El'gygytgyn Crater. The total core sequence is interpreted as strata building up a progradational alluvial fan delta. Four macroscopically distinct sedimentary units are identified. Unit 1 (141.5-117.0 m) is comprised of ice-cemented, matrix-supported sandy gravel and intercalated sandy layers. Sandy layers represent sediments which rained out as particles in the deeper part of the water column under highly energetic conditions. Unit 2 (117.0-24.25 m) is dominated by ice-cemented, matrix-supported sandy gravel with individual gravel layers. Most of the Unit 2 diamicton is understood to result from alluvial wash and subsequent gravitational sliding of coarse-grained (sandy gravel) material on the basin slope. Unit 3 (24.25-8.5 m) has icecemented, matrix-supported sandy gravel that is interrupted by sand beds. These sandy beds are associated with flooding events and represent near-shore sandy shoals. Unit 4 (8.5-0.0 m) is ice-cemented, matrix-supported sandy gravel with varying ice content, mostly higher than below. It consists of slope material and creek fill deposits. The uppermost metre is the active layer (i.e. the top layer of soil with seasonal freeze and thaw) into which modern soil organic matter has been incorporated. The nature of the progradational sediment transport taking place from the western and northern crater margins may be related to the complementary occurrence of frequent turbiditic layers in the central lake basin, as is known from the lake sediment record. Slope processes such as gravitational sliding and sheet flooding occur especially during spring melt and promote mass wasting into the basin. Tectonics are inferred to have initiated the fan accumulation in the first place and possibly the off-centre displacement of the crater lake.

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Section: Geographical Setting Of El'gygytgyn Cratermentioning

confidence: 99%

Depositional dynamics in the El'gygytgyn Crater margin: implications for the 3.6 Ma old sediment archive

Schwamborn¹,

Fedorov²,

Ostanin³

et al. 2012

Clim. Past

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“…• C at 20 m depth (Mottaghy al., 2012). Permafrost thickness is estimated to be around 350 m based on borehole temperature measurements in hole 5011-3 (Mottaghy et al, 2012). Air temperature extremes in 2003 ranged from −40 • C to 26…”

Section: Geographical Setting Of El'gygytgyn Cratermentioning

confidence: 99%

Alluvial fan dynamics in the El'gygytgyn Crater: implications for the 3.6 Ma old sediment archive

Schwamborn¹,

Fedorov²,

Ostanin³

et al. 2012

Preprint

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A sedimentological program has been conducted using frozen core samples from the 141.5 m long El'gygytgyn 5011-3 permafrost well. The drill site is located in sedimentary permafrost west of the lake that partly fills the El'gygytgyn Crater. The total core sequence is interpreted as strata building up a progradational alluvial fan delta. Four structurally and texturally distinct sedimentary units are identified. Unit 1 (141.5–117.0 m) is comprised of ice-cemented, matrix-supported sandy gravel and intercalated sandy layers. Sandy layers represent sediments which rained out as particles in the deeper part of the water column under highly energetic conditions. Unit 2 (117.0–24.25 m) is dominated by ice-cemented, matrix-supported sandy gravel with individual gravel layers. Most of the unit 2 diamicton is understood to result from alluvial wash and subsequent gravitational sliding of coarse-grained material on the basin slope. Unit 3 (24.25–8.5 m) has ice-cemented, matrix-supported sandy gravel that is interrupted by sand beds. These sandy beds are associated with flooding events and represent near-shore sandy shoals. Unit 4 (8.5–0.0 m) is ice-cemented, matrix-supported sandy gravel with varying ice content, mostly higher than below. It consists of slope material and creek fill deposits. The uppermost meter is the active layer into which modern soil organic matter has been incorporated. The nature of the progradational sediment transport taking place from the western and northern crater margins may be related to the complementary occurrence of frequent turbiditic layers in the central lake basin as is known from the lake sediment record. Slope processes such as gravitational sliding and sheet flooding that takes place especially during spring melt are thought to promote mass wasting into the basin. Tectonics are inferred to have initiated the fan accumulation in the first place and possibly the off-centre displacement of the crater lake

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

Vogel¹,

Meyer-Jacob²,

Melles³

et al. 2012

Preprint

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Here we present a detailed multiproxy record of the climate and environmental evolution at Lake El'gygytgyn/Far East Russian Arctic during the period 430–395 ka covering the Marine Isotope Stage (MIS) 12/11 transition and the thermal maximum of super interglacial MIS 11. The MIS 12/11 transition at Lake El'gygytgyn is characterized by initial warming followed by a cold reversal implying similarities to the Bølling/Allerød (B/A) to Younger Dryas (YD) pattern of the last deglaciation. Full and remarkably stable interglacial conditions with mean temperatures of warmest month (MTWM) ranging between ca. 10–15 °C, annual precipitation (PANN) ranging between ca. 300–600 mm, strong in-lake productivity, coincide with dark coniferous forests in the catchment, annual disintegration of the lake ice cover and full mixis of the water column. Such conditions persisted for ca. 27 kyrs between ca. 425–398 ka. The Lake El'gygytgyn record closely resembles the climate pattern recorded in Lake Baikal (SE Siberia) sediments and Antarctic ice cores implying strong teleconnections between Northern and Southern Hemispheres during MIS 11. A peak warm period between ca. 418–415.5 ka and a precipitation anomaly at ca. 401 ka at Lake El'gygytgyn, in contrast, appear to be an expression of more regionally confined climate variations

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Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modelling

Cited by 4 publications

References 49 publications

Depositional dynamics in the El'gygytgyn Crater margin: implications for the 3.6 Ma old sediment archive

Depositional dynamics in the El'gygytgyn Crater margin: implications for the 3.6 Ma old sediment archive

Alluvial fan dynamics in the El'gygytgyn Crater: implications for the 3.6 Ma old sediment archive

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

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