scholarly journals Late Pliocene and early Pleistocene environments of the north-eastern Russian Arctic inferred from the Lake El'gygytgyn pollen record

2013 ◽  
Vol 9 (4) ◽  
pp. 4599-4653 ◽  
Author(s):  
A. A. Andreev ◽  
P. E. Tarasov ◽  
V. Wennrich ◽  
E. Raschke ◽  
U. Herzschuh ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Lacustrine Sediments ◽  
Early Pleistocene ◽  
Pollen Record ◽  
Russian Arctic ◽  
Coprophilous Fungi ◽  
Climate Conditions ◽  
Late Pliocene ◽  
The North ◽  
Lake El’Gygytgyn

Abstract. The 318 m thick lacustrine sediment record in Lake El'gygytgyn, northeastern Russian Arctic cored by the international El'gygytgyn Drilling Project provides unique opportunities allowing the time-continuous reconstruction of the regional paleoenvironmental history for the past 3.6 Myr. Pollen studies of the lower 216 m of the lacustrine sediments show their value as an excellent archive of vegetation and climate changes during the Late Pliocene and Early Pleistocene. About 3.50–3.35 Myr BP the vegetation at Lake El'gygytgyn, in nowadays tundra area, was dominated by spruce-larch-fir-hemlock forests. After ca. 3.4 Myr BP dark coniferous taxa gradually disappeared. A very pronounced environmental changes took place at ca. 3.305–3.275 Myr BP, corresponding with the Marine Isotope Stage (MIS) M2, when treeless tundra- and steppe-like habitats became dominant in the regional vegetation. Climate conditions were similar to those of Late Pleistocene cold intervals. Numerous coprophilous fungi spores identified in the pollen samples suggest the presence of grazing animals around the lake. Following the MIS M2 event, larch-pine forests with some spruce mostly dominated in the area until ca. 2.6 Myr BP, interrupted by colder and drier intervals ca. 3.04–3.02, 2.93–2.91, and 2.725–2.695 Myr BP. At the beginning of the Pleistocene, ca. 2.6 Myr BP, noticeable climatic deterioration occurred. Forested habitats changed to predominantly treeless and shrubby environments, which reflect a relatively cold and dry climate. Revealed peaks in green algae colonies (Botryococcus) around 2.53, 2.45, 2.320–2.305 and 2.175–2.150 Myr BP suggest a spread of shallow water environments. Few intervals (i.e. 2.55–2.53, ca. 2.37, and 2.35–2.32 Myr BP) with a higher presence of coniferous taxa (mostly pine and larch) document some relatively short-term climate ameliorations.

scholarly journals Late Pliocene and Early Pleistocene vegetation history of northeastern Russian Arctic inferred from the Lake El'gygytgyn pollen record

2014 ◽  
Vol 10 (3) ◽  
pp. 1017-1039 ◽  
Author(s):  
A. A. Andreev ◽  
P. E. Tarasov ◽  
V. Wennrich ◽  
E. Raschke ◽  
U. Herzschuh ◽  
...  
Keyword(s):  
Vegetation History ◽  
Lacustrine Sediments ◽  
Early Pleistocene ◽  
Pollen Record ◽  
Russian Arctic ◽  
Coprophilous Fungi ◽  
Climate Conditions ◽  
Late Pliocene ◽  
Lake El’Gygytgyn ◽  
History Of

Abstract. The 318 m thick lacustrine sediment record from Lake El'gygytgyn, northeastern Russian Arctic cored by the international El'gygytgyn Drilling Project provides unique opportunities for the time-continuous reconstruction of the regional paleoenvironmental history for the past 3.6 Myr. Pollen studies of the lower 216 m of the lacustrine sediments demonstrate their value as an excellent archive of vegetation and climate changes during the Late Pliocene and Early Pleistocene. About 3.5–3.35 Myr BP, the vegetation at Lake El'gygytgyn, now an area of tundra was dominated by spruce-larch-fir-hemlock forests. After ca. 3.35 Myr BP dark coniferous taxa gradually disappeared. A very pronounced environmental change took place ca. 3.31–3.28 Myr BP, corresponding to the Marine Isotope Stage (MIS) M2, when treeless tundra- and steppe-like habitats became dominant in the regional vegetation. Climate conditions were similar to those of Late Pleistocene cold intervals. Numerous coprophilous fungi spores identified in the pollen samples suggest the presence of grazing animals around the lake. Following the MIS M2 event, larch-pine forests with some spruce mostly dominated the area until ca. 2.6 Myr BP, interrupted by colder and drier intervals ca. 3.043–3.025, 2.935–2.912, and 2.719–2.698 Myr BP. At the beginning of the Pleistocene, ca. 2.6 Myr BP, noticeable climatic deterioration occurred. Forested habitats changed to predominantly treeless and shrubby environments, which reflect a relatively cold and dry climate. Peaks in observed green algae colonies (Botryococcus) around 2.53, 2.45, 2.32–2.305, 2.20 and 2.16–2.15 Myr BP suggest a spread of shallow water environments. A few intervals (i.e., 2.55–2.53, ca. 2.37, and 2.35–2.32 Myr BP) with a higher presence of coniferous taxa (mostly pine and larch) document some relatively short-term climate ameliorations during Early Pleistocene glacial periods.

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

2014 ◽  
Vol 10 (4) ◽  
pp. 1381-1399 ◽  
Author(s):  
V. Wennrich ◽  
P. S. Minyuk ◽  
V. Borkhodoev ◽  
A. Francke ◽  
B. Ritter ◽  
...  
Keyword(s):  
North Pacific ◽  
Far East ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Gradual Transition ◽  
Russian Arctic ◽  
Lake Productivity ◽  
The North ◽  
Lake El’Gygytgyn ◽  
The North Pacific

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.

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

2013 ◽  
Vol 9 (5) ◽  
pp. 5899-5940 ◽  
Author(s):  
V. Wennrich ◽  
P. S. Minyuk ◽  
V. Ya. Borkhodoev ◽  
A. Francke ◽  
B. Ritter ◽  
...  
Keyword(s):  
Environmental History ◽  
Far East ◽  
Climatic Conditions ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Gradual Transition ◽  
Russian Arctic ◽  
Lake Productivity ◽  
The North ◽  
Lake El’Gygytgyn

Abstract. The 3.6 Ma sediment record of Lake El'gygytgyn, Far East Russian Arctic, represents the longest continuous climate archive of the terrestrial Arctic. Its elemental composition monitored by X-ray fluorescence scanning exhibits significant changes since the Mid-Pliocene caused by climate driven variations in the primary production, postsedimentary diagenetic processes, and current activity in the lake 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 highly masked by intensified detrital input from the catchment, visible in maxima of clastic-related proxies such as the K concentration. In addition, calcite formation in the early lake history points to enhanced nutrient flux into the lake caused by intensified weathering in its catchment. Its termination at ca. 3.3 Ma is supposed to be linked to the development of permafrost in the region triggered by a first cooling in the Mid-Pliocene. After ca. 3.0 Ma the elemental data suggest a gradual transition to Quaternary-style glacial / interglacial cyclicity. In the early Pleistocene, the cyclicity was first dominated by variations on the 41 ka obliquity band but experienced a change to a 100 ka eccentricity dominance after the Middle Pleistocene Transition at ca. 1.2 to 0.7 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 to 1.8 Ma reflects an overall change in the bottom water oxygenation due to an intensified occurrence of pervasive glacial episodes in the early Quaternary. 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 regional cooling and/or changes in the ocean-land moisture transport. Further rising TOC and TN values after ca. 1.6 Ma are attributed to a progressive intensification of the glacial intensity. In the course of the Quaternary glacial/interglacial sequence eight so-called "super-interglacials" occur. Their exceptional warm conditions are reflected by extreme Si / Ti peaks accompanied by lows in Ti, K, and Fe, thus indicating an extraordinary high lake productivity.

scholarly journals A 900-year New England temperature reconstruction from <i>in situ</i> seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs)

2018 ◽  
Author(s):  
Daniel R. Miller ◽  
M. Helen Habicht ◽  
Benjamin A. Keisling ◽  
Isla S. Castañeda ◽  
Raymond S. Bradley
Keyword(s):  
New England ◽  
Water Column ◽  
Lacustrine Sediments ◽  
Temperature Reconstruction ◽  
Early Spring ◽  
Pollen Record ◽  
The North ◽  
The North Atlantic Oscillation ◽  
Glycerol Dialkyl Glycerol Tetraethers

Abstract. Paleotemperature reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleoclimatology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in lacustrine sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. We report seasonally resolved measurements of brGDGT production within the water column, in catchment soils and in a sediment sequence from a small, deep inland lake in Maine, USA. BrGDGT distributions in the water column are distinct from catchment soils but similar to the distributions in lake sediments, suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the downcore sedimentary signal. Seasonally, depth-resolved measurements indicate that the dominant production of brGDGTs occurs in late fall/early spring and at intermediate depths (18–30 meters) in the water column. We apply these observations to help interpret a 900-year-long brGDGT-based temperature reconstruction and find that it shows similar trends to a pollen record from the same site and to regional and global syntheses of terrestrial temperatures over the last millennium. However, the record also shows higher-frequency variability than has previously been captured by such an archive in the Northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic/solar activity. This is the first brGDGT- based multi-centennial paleoreconstruction from this region and contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.

Vegetation and climate during the penultimate interglacial of the northeastern Russian Arctic: the Lake El'gygytgyn pollen record

Boreas ◽  
2019 ◽  
Vol 48 (2) ◽  
pp. 507-515 ◽  
Author(s):  
Wenwei Zhao ◽  
Andrei A. Andreev ◽  
Pavel E. Tarasov ◽  
Volker Wennrich ◽  
Martin Melles
Keyword(s):  
Pollen Record ◽  
Russian Arctic ◽  
Lake El’Gygytgyn ◽  
Vegetation And Climate

Late Quaternary Vegetational Changes in a Marsh Forest in Southeastern Brazil with Comments on Prehistoric Human Occupation

Radiocarbon ◽  
2015 ◽  
Vol 57 (5) ◽  
pp. 737-753 ◽  
Author(s):  
Walter Mareschi Bissa ◽  
Mauro B de Toledo
Keyword(s):  
Sediment Core ◽  
Environmental Changes ◽  
Human Impacts ◽  
Late Quaternary ◽  
Southeastern Brazil ◽  
Pollen Record ◽  
Important Indicator ◽  
Climate Conditions ◽  
Ams Radiocarbon Dating ◽  
Se Brazil

This article presents a palynological study carried out on a sediment core from a peat deposit in Serra de Botucatu, in SÃo Paulo State, southeastern Brazilian Plateau. This region has been covered by grassland vegetation and forest patches throughout the recorded period. AMS radiocarbon dating plus palynological analysis of 27 samples from the sediment core allowed the recognition of several environmental changes that took place during the last 33,000 yr recorded in the core. The relationship between sedimentation rates and changes in the abundance of plants recognized through their pollen record, particularly a few important indicator species, provided the paleoenvironmental history for the Serra de Botucatu region, allowing the identification of changes in climate conditions and comparison with other regions in Brazil. One of the most remarkable features of this record is the cold and humid conditions during the Last Glacial Maximum, which diverges from previous interpretations for southeastern and southern Brazil but is in good agreement with paleoclimatic data from trace elements from cave stalagmites in SE Brazil. No indications of human impacts on the vegetation were found in this record.

scholarly journals Preliminary study of fossil freshwater molluscs from the Plio-Pleistocene Kathmandu Basin sediments, central Nepal

2001 ◽  
Vol 25 ◽  
Author(s):  
Damayanti Gurung ◽  
Katsumi Takayasu ◽  
Hasko Nesemann
Keyword(s):  
Lacustrine Sediments ◽  
Early Pleistocene ◽  
Bivalve Species ◽  
Faunal Composition ◽  
Late Pliocene ◽  
Freshwater Molluscs ◽  
Central Nepal ◽  
Molluscan Fauna ◽  
Preliminary Study ◽  
Molluscan Species

Fossils of freshwater Mollusca from the fluvio-lacustrine sediments of the Kathmandu Basin are collected from localities in the upper part of the Lukundol Formation, of Late Pliocene to Early Pleistocene age, and the Gokarna Formation, of Late Pleistocene age. Despite the temporal differences of the two localities, the dominant molluscan species in each locality are similar. The fossil molluscan fauna in the older Lukundol Formation is entirely composed of prosobranch gastropod shells belonging to the genus Bellamya and opercula of the genus Digoniostoma. The fauna in the younger Gokarna Formation includes similar prosobranch species with addition of one prosobranch species, along with three pulmonate gastropods, an unidentified terrestrial gastropod and a bivalve species. The additional prosobranch species belong to the genus Gabbia, and the pulmonate gastropods are of the genera Lymnaea, Gyraulus, and Planorbis. The only bivalve species belong to the genus Pisidium. In the Lukundol Formation, fossil molluscan shells are abundant but poor in number of species and the assemblage is dominated by lacustrine taxa preferring permanent lentic water body of shallow depth. Conversely, in the Gokarna Formation, species diversity is comparatively higher, with inhabitant of the shallow lacustrine to marginal less stable habitats. The fossil molluscan faunal composition is more similar to the recent fauna that inhabits the warmer southern Terai region of Nepal.

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