Dust sedimentation rates in loess-soil formation of Caspian Depression and it's correlation with Late Quaternary transgressions and regressions of Caspian sea
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Abstract Knowledge of sea-level change in the southern Baltic Sea region is important for understanding the variations in late Pleistocene and Holocene sea-level change across northern Europe. These variations are a consequence of the response of the Earth's crust to the deglaciation of Fennoscandia and of the water added to the oceans from the melting of all Pleistocene ice sheets. The sedimentological and geochemical composition of five sediment cores from the lagoonal Oder Estuary offers new observational evidence for sea-level change and coastal development in the southern Baltic Sea region. The combined use of several geochemical proxies (organic carbon, nitrogen, calcium carbonate and biogenic opal contents, C org /S and C org /N ratios, δ 13 C values of organic matter, and δ 15 N values) is a new approach for the study area. The chemical evidence of this multiproxy approach allows clear identification of several stages in the development of the lagoonal environment: postglacial lake stages with sandy sedimentation during the Older Dryas and the Allerød stades, lacustrine phases with high autochthonous productivity during the Atlantic stade, terrestrial stages with peat formation at the beginning of the Subboreal stade, sedimentation as a result of marine transgression, and brackish sedimentation after the formation of sand spits and barrier islands during the Subatlantic stade. The stages are the result of regional sea-level change owing to complex shoreline development. They support the tentative sea-level curve proposed nearly 20 years ago for the region. In addition, changes in Oder River input in response to climate conditions is monitored. Whereas high terrigenous input of organic matter from the Oder River occurred during periods of humid climate during the Allerød, Atlantic, and Subatlantic stades, Oder River discharge decreased with drier and cooler climate conditions during the Subboreal stade. Furthermore, the geochemical evidence points to local anomalies such as the significance of river input and additional sulfate supply into the Oder lagoon for the composition of the sediments. Overall, the results provide a framework for future studies, which would allow for a more detailed comparison with other, similar environments.
Deglaciation
Marine transgression
Preboreal
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The geology and mammal and mollusk fauna from the Late Pleistocene locality Sanmanych (the single location of paleontological remains in the Manych basin) in Rostov region are discussed. The received data permit to reconstruct the climatic-environmental condition during the Early Khvalynian transgression in the Manych basin. This transgression was dated by 14 C in the interval between 16–12 kyr BP. As a result of the formation of a Cascade of Eurasian Basins for the first time in the Late Pleistocene Caspian waters of the Khvalynian Sea had flooded to the Manych depression and the Manych-Kerch strait was originated during that time. The marine mollusks appeared in the Manych basin together with Caspian Sea water. The salinity of Khvalynian basin was close to the same of the Caspian Sea (10–12%) and the water temperature was lower than recent one, what confirms by the fact that mollusk’ shells were two-three times smaller than the modern ones of the same species. The analysis of the small mammal fauna permits to reconstruct the arid open landscapes during the formation of the location. The lower mammal diversity indicates the unfavorable climatic and environment conditions – the high aridity and the rather cool climate.
Marine transgression
Mammal
Early Pleistocene
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BENGAL
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Paleosol
Chronology
Last Glacial Maximum
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Paleoclimatology
Marine transgression
Subaerial
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The article is devoted to a reconstruction of the sedimentation processes in Kamyshovoye Lake (the Kaliningrad Region, Russia) during the Late Glacial and Holocene. The results of the geochemical analysis of Kamyshovoye Lake’s bottom sediments, accompanied by statistical processing and detailed radiocarbon dating, are presented. It was established that a high proportion of mineral matter dominated in the intervals between 15,000 and 11,400 and between 1400 and 600 cal y BP; enrichment with carbonates was noted between 11,400 and 5200 cal y BP and during the past 600 years; and a high percentage of organic matter was recorded between 7800 and 600 cal y BP. We conclude that the increase in mineral matter was influenced by such factors as reduced vegetation cover due to natural and anthropogenic processes, aeolian transfer, and dead-ice melting during the Late Glacial. The increase in carbonate matter was mainly associated with humidity and the reduction conditions of the lake ecosystem. Organogenic matter content was affected by the autochthonic (biological) productivity of the lake, which directly depends on more favorable climatic conditions.
Sedimentation
Last Glacial Maximum
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Depression
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The results of the palynological analysis and 14 C dating of the most complete sequences of the Holocene sediments were used for a detailed reconstruction of multi-cyclic alternations of climate phases and zonal and intrazonal plant formations that were taking place the Lower Volga region during the last ten thousand years. Twenty-six phases in evolution of the natural environment during the Holocene were distinguished. Landscape-climatic characteristics and chronological boundaries were identified for these phases. Reconstructed paleoclimatic stages were correlated to the Holocene transgressions and regressions in the Caspian Sea region. The model developed for periodization of climatic events may serve as a climato-stratigraphical framework for future paleogeographical studies of the Holocene in the Northern Caspian region.
Holocene climatic optimum
Volga region
Periodization
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Marine transgression
Lithology
Sedimentation
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New palynological and ostracod data are presented from the Holocene Volga delta, obtained from short cores and surface samples collected in the Damchik region, near Astrakhan, Russian Federation in the northern Caspian Sea. Four phases of delta deposition are recognized and constrained by accelerated mass spectrometry (AMS) radiocarbon ages. Palynological records show that erosive channels, dunes (Baer hills) and inter-dune lakes were present during the period 11,500–8900 cal. BP at the time of the Mangyshlak Caspian lowstand. The period 8900–3770 cal. BP was characterized regionally by extensive steppe vegetation, with forest present at times with warmer, more humid climates, and with halophytic and xerophytic vegetation present at times of drought. The period 3770–2080 cal. BP was a time of active delta deposition, with forest or woodland close to the delta, indicating relatively warm and humid climates and variable Caspian Sea levels. From 2080 cal. BP to the present-day, aquatic pollen is frequent in highstand intervals and herbaceous pollen and fungal hyphae frequent in lowstand intervals. Soils and incised valley sediments are associated with the regional Derbent regression and may be time-equivalent with the ‘Medieval Warm Period’. Fungal spores are an indicator of erosional or aeolian processes, whereas fungal hyphae are associated with soil formation. Freshwater algae, ostracods and dinocysts indicate mainly freshwater conditions during the Holocene with minor brackish influences. Dinocysts present include Spiniferites cruciformis, Caspidinium rugosum, Impagidinium caspienense and Pterocysta cruciformis, the latter a new record for the Caspian Sea. The Holocene Volga delta is a partial analogue for the much larger oil and gas bearing Mio-Pliocene palaeo-Volga delta.
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Steppe
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