BIOMARKER BASED PALEOTEMPERATURES FROM AN ARCTIC SUPER INTERGLACIAL: MARINE ISOTOPE STAGES 33-31 AT LAKE EL'GYGYTGYN

Abstract. Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea–Larix–Betula–Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial–interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula–Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios.

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Quantitative and qualitative constraints on hind-casting the formation of multiyear lake-ice covers at Lake El'gygytgyn

Climate of the Past ◽

10.5194/cp-9-1253-2013 ◽

2013 ◽

Vol 9 (3) ◽

pp. 1253-1269 ◽

Cited By ~ 15

Author(s):

M. Nolan

Keyword(s):

Water Exchange ◽

Sediment Cores ◽

Ice Cover ◽

Lake Ice ◽

Ice Growth ◽

Temperature Reduction ◽

Air Temperatures ◽

Lake El’Gygytgyn ◽

Oxygen Conditions ◽

Multiyear Ice

Abstract. Analysis of the 3.6 Ma, 318 m long sediment core from Lake El'gygytgyn suggests that the lake was covered by ice for millennia at a time for much of its history and therefore this paper uses a suite of existing, simple, empirical degree-day models of lake-ice growth and decay to place quantitative constraints on air temperatures needed to maintain a permanent ice cover on the lake. We also provide an overview of the modern climatological and physical processes that relate to lake-ice growth and decay as a basis for evaluating past climate and environmental conditions. Our modeling results indicate that modern annual mean air temperature would only have to be reduced by 3.3 °C ± 0.9 °C to initiate a multiyear ice cover and a temperature reduction of at least 5.5 °C ± 1.0 °C is likely needed to completely eliminate direct air–water exchange of oxygen, conditions that have been inferred at Lake El'gygytgyn from the analysis of sediment cores. Once formed, a temperature reduction of only 1–3 °C relative to modern may be all that is required to maintain multiyear ice. We also found that formation of multiyear ice covers requires that positive degree days are reduced by about half the modern mean, from about +608 to +322. A multiyear ice cover can persist even with summer temperatures sufficient for a two-month long thawing period, including a month above +4 °C. Thus, it is likely that many summer biological processes and some lake-water warming and mixing may still occur beneath multiyear ice-covers even if air–water exchange of oxygen is severely restricted.

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Chronology of Lake El'gygytgyn sediments – a combined magnetostratigraphic, palaeoclimatic and orbital tuning study based on multi-parameter analyses

Climate of the Past ◽

10.5194/cp-9-2413-2013 ◽

2013 ◽

Vol 9 (6) ◽

pp. 2413-2432 ◽

Cited By ~ 44

Author(s):

N. R. Nowaczyk ◽

E. M. Haltia ◽

D. Ulbricht ◽

V. Wennrich ◽

M. A. Sauerbrey ◽

...

Keyword(s):

Global Climate ◽

Far East ◽

Climatic Conditions ◽

Sedimentation Rates ◽

Scientific Drilling ◽

Lake El’Gygytgyn ◽

Age Model ◽

Orbital Tuning ◽

Lake Floor ◽

The Impact

Abstract. A 318-metre-long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP) at Site 5011-1 in Lake El'gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chronostratigraphic methods. The 12 km wide lake is sited off-centre in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the earth's magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest geomagnetic Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El'gygytgyn occurred in concert with global climatic cycles. The upper ~160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1. This study also provides orbitally tuned ages for a total of 8 tephras deposited in Lake El'gygytgyn.

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Amplified bioproductivity during Transition IV (332 000–342 000 yr ago): evidence from the geochemical record of Lake El'gygytgyn

Climate of the Past ◽

10.5194/cp-9-679-2013 ◽

2013 ◽

Vol 9 (2) ◽

pp. 679-686 ◽

Cited By ~ 8

Author(s):

L. Cunningham ◽

H. Vogel ◽

V. Wennrich ◽

O. Juschus ◽

N. Nowaczyk ◽

...

Keyword(s):

Sharp Increase ◽

Biogenic Silica ◽

Ice Cores ◽

Climatic Conditions ◽

The Arctic ◽

Significant Shift ◽

Geochemical Parameters ◽

Lake El’Gygytgyn ◽

Arctic Russia

Abstract. To date, terrestrial archives of long-term climatic change within the Arctic have widely been restricted to ice cores from Greenland and, more recently, sediments from Lake El'gygytgyn in northeast Arctic Russia. Sediments from this lake contain a paleoclimate record of glacial-interglacial cycles during the last three million years. Low-resolution studies at this lake have suggested that changes observed during Transition IV (the transition from marine isotope stage (MIS) 10 to MIS 9) are of greater amplitude than any observed since. In this study, geochemical parameters are used to infer past climatic conditions thus providing the first high-resolution analyses of Transition IV from a terrestrial Arctic setting. These results demonstrate that a significant shift in climate was subsequently followed by a rapid increase in biogenic silica (BSi) production. Following this sharp increase, bioproductivity remained high, but variable, for over a thousand years. This study reveals differences in the timing and magnitude of change within the ratio of silica to titanium (Si/Ti) and BSi records that would not be apparent in lower resolution studies. This has significant implications for the increasingly common use of Si/Ti data as an alternative to traditional BSi measurements.

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High-temperature thermomagnetic properties of vivianite nodules, Lake El'gygytgyn, Northeast Russia

Climate of the Past ◽

10.5194/cp-9-433-2013 ◽

2013 ◽

Vol 9 (1) ◽

pp. 433-446 ◽

Cited By ~ 14

Author(s):

P. S. Minyuk ◽

T. V. Subbotnikova ◽

L. L. Brown ◽

K. J. Murdock

Keyword(s):

Magnetic Susceptibility ◽

High Temperature ◽

Magnetic Measurements ◽

Iron Phosphate ◽

Northeastern Russia ◽

Northeast Russia ◽

Low Field ◽

Lake El’Gygytgyn ◽

Monoclinic Pyrrhotite ◽

Thermomagnetic Properties

Abstract. Vivianite, a hydrated iron phosphate, is abundant in sediments of Lake El'gygytgyn, located in the Anadyr Mountains of central Chukotka, northeastern Russia (67°30′ N, 172°05′ E). Magnetic measurements, including mass-specific low-field AC magnetic susceptibility, field-dependent magnetic susceptibility, hysteresis parameters, temperature dependence of the induced magnetization, as well as susceptibility in different heating media, provide ample information on vivianite nodules. Electron microprobe analyses, electron microscopy and energy dispersive spectroscopy were used to identify diagnostic minerals. Vivianite nodules are abundant in both sediments of cold (anoxic) and warm (oxic) stages. Magnetic susceptibility of the nodules varies from 0.78 × 10−6 m3 kg−1 to 1.72 × 10−6 m3 kg−1 (average = 1.05 × 10−6 m3 kg−1) and is higher than the susceptibility of sediments from the cold intervals. Magnetic properties of vivianite are due to the respective product of oxidation as well as sediment and mineral inclusions. Three types of curves for high-temperature dependent susceptibility of vivianite indicate different degrees of oxidation and inclusions in the nodules. Vivianite acts as a reductant and reduces hematite to magnetite and masks the goethite–hematite transition during heating. Heating vivianite and sulfur mixtures stimulates the formation of monoclinic pyrrhotite. An additive of arsenic inhibits the formation of magnetite prior to its Curie temperature. Heating selective vivianite and pyrite mixtures leads to formation of several different minerals – magnetite, monoclinic pyrrhotite, and hexagonal pyrrhotite, and makes it difficult to interpret the thermomagnetic curves.

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Petrophysical characterization of the lacustrine sediment succession drilled in Lake El'gygytgyn, Far East Russian Arctic

Climate of the Past Discussions ◽

10.5194/cpd-9-351-2013 ◽

2013 ◽

Vol 9 (1) ◽

pp. 351-391 ◽

Cited By ~ 4

Author(s):

A. C. Gebhardt ◽

A. Francke ◽

J. Kück ◽

M. Sauerbrey ◽

F. Niessen ◽

...

Keyword(s):

Mass Movement ◽

Far East ◽

Lacustrine Sediments ◽

Lacustrine Sediment ◽

Organic Carbon Content ◽

Meteorite Impact ◽

Seismic Profiles ◽

Scientific Drilling ◽

Lake El’Gygytgyn ◽

Lake Floor

Abstract. Seismic profiles of Far East Russian Lake El'gygytgyn which was formed by a meteorite impact some 3.6 million years ago show a stratified sediment succession that can be separated into Subunits Ia and Ib at approximately 167 m below lake floor (= ∼ 3.17 Ma). The former is well-stratified, while the latter is acoustically more massive. The sediments are intercalated with frequent mass movement deposits mainly in the proximal parts, while the distal part is almost free of such deposits at least in the upper part. In spring 2009, a long core drilled in the lake center within the framework of the International Continental Scientific Drilling Program (ICDP) penetrated the entire lacustrine sediment succession down to ~ 320 m below lake floor and about 200 m further into the meteorite-impact related bedrock. Downhole logging data down to 390 m below lake floor show that the bedrock and the lacustrine part of the core differ largely in their petrophysical characteristics. The contact between the bedrock and the lacustrine sediments is not abrupt, but rather transitional with a mixture of impact-altered bedrock clasts in a lacustrine matrix with varying percentages. Physical and chemical proxies measured on the cores can be used to divide the lacustrine part into five different clusters. These can be plotted in a redox-condition vs. input type diagram with total organic carbon content and magnetic susceptibility values indicating anoxic or oxic conditions and with the Si/Ti ratio representing more clastic or more biogenic input. Plotting the clusters in this diagram allows identifying clusters that represent glacial phases (Cluster I), super interglacials (Cluster II), and interglacial phases (Clusters III and IV).

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The diatom flora in the ultra-oligotrophic Lake El'gygytgyn, Chukotka

Polar Biology ◽

10.1007/s00300-002-0445-0 ◽

2003 ◽

Vol 26 (2) ◽

pp. 105-114 ◽

Cited By ~ 58

Author(s):

Holger Cremer ◽

Bernd Wagner

Keyword(s):

Oligotrophic Lake ◽

Diatom Flora ◽

Lake El’Gygytgyn

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Modern isotope hydrology and controls on δD of plant leaf waxes at Lake El'gygytgyn, NE Russia

Climate of the Past ◽

10.5194/cp-9-335-2013 ◽

2013 ◽

Vol 9 (1) ◽

pp. 335-352 ◽

Cited By ~ 23

Author(s):

K. M. K. Wilkie ◽

B. Chapligin ◽

H. Meyer ◽

S. Burns ◽

S. Petsch ◽

...

Keyword(s):

Sediment Cores ◽

Winter Precipitation ◽

Mean Value ◽

Great Promise ◽

Plant Leaf ◽

Hydrologic Processes ◽

Leaf Waxes ◽

Lake El’Gygytgyn ◽

Alkanoic Acids ◽

Hydrogen Isotope Ratios

Abstract. Stable isotope data from lipid biomarkers and diatom silica recovered from lake sediment cores hold great promise for paleoclimate and paleohydrological reconstructions. However, these records rely on accurate calibration with modern precipitation and hydrologic processes and only limited data exist on the controls on the δD values for n-alkanoic acids from plant leaf waxes. Here we investigate the stable isotopic composition of modern precipitation, streams, lake water and ice cover, and use these data to constrain isotope systematics of the Lake El'gygytgyn Basin hydrology. Compound-specific hydrogen isotope ratios determined from n-alkanoic acids from modern vegetation are compared with modern precipitation and lake core top sediments. Multi-species net (apparent) fractionation values between source water (precipitation) and modern vegetation (e.g., &varepsilon;wax/precip mean value is −107 ± 12‰) agree with previous results and suggest a consistent offset between source waters and the δD values of alkanoic acids. We conclude that although there may be some bias towards a winter precipitation signal, overall δD values from leaf wax n-alkanoic acids record annual average precipitation within the El'gygytgyn Basin. A net fractionation calculated for 200-yr-integrated lake sediments yields &varepsilon;30/precip = −96 ± 8‰ and can provide robust net "apparent" fractionation to be used in future paleohydrological reconstructions.

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