The Ponto-Caspian basin as a final trap for southeastern Scandinavian Ice-Sheet meltwater

This paper provides new data on the evolution of the Caspian Sea and Black Sea from the Last Glacial Maximum until ca. 12 cal kyr BP. We present new analyses (clay mineralogy, grain-size, Nd isotopes and pollen) applied to sediments from the river terraces in the lower Volga, from the middle Caspian Sea and from the western part of the Black Sea. The results show that during the last deglaciation, the Ponto-Caspian basin collected meltwater and fine-grained sediment from the southern margin of the Scandinavian Ice Sheet (SIS) via the Dniepr and Volga Rivers. It induced the deposition of characteristic red-brownish/chocolate-coloured illite-rich sediments (Red Layers in the Black Sea and Chocolate Clays in the Caspian Sea) that originated from the Baltic Shield area according to Nd data. This general evolution, common to both seas was nevertheless differentiated over time due to the specificities of their catchment areas and due to the movement of the southern margin of the SIS. Our results indicate that in the eastern part of the East European Plain, the meltwater from the SIS margin supplied the Caspian Sea during the deglaciation until ∼13.8 cal kyr BP, and possibly from the LGM. That led to the Early Khvalynian transgressive stage(s) and Chocolate Clays deposition in the now-emerged northern flat part of the Caspian Sea (river terraces in the modern lower Volga) and in its middle basin. In the western part of the East European Plain, our results confirm the release of meltwater from the SIS margin into the Black Sea that occurred between 17.2 and 15.7 cal kyr BP, as previously proposed. Indeed, recent findings concerning the evolution of the southern margin of the SIS and the Black Sea, show that during the last deglaciation, occurred a westward release of meltwater into the North Atlantic (between ca. 20 and 16.7 cal kyr BP), and a southward one into the Black Sea (between 17.2 and 15.7 cal kyr BP). After the Red Layers/Chocolate Clays deposition in both seas and until 12 cal kyr BP, smectite became the dominant clay mineral. The East European Plain is clearly identified as the source for smectite in the Caspian Sea sediments. In the Black Sea, smectite originated either from the East European Plain or from the Danube River catchment. Previous studies consider smectite as being only of Anatolian origin. However, our results highlight both, the European source for smectite and the impact of this source on the depositional environment of the Black Sea during considered period

Magnetic properties of sediments in a Polish lake: Evidence of a relation between rock-magnetic properties and environmetal changes in Late Pleistocene and Holocene sediments

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Mineral magnetic record of environment in Late Pleistocene and Holocene sediments, Lake Manas, Xinjiang, China

International audienceA study of magnetic parameters was carried out on a Late Pleistocene and Holocene sedimentary sequence (5 m) from Lake Manas (northern Xinjiang, China), that has already been analysed for bulk sediment mineralogy, stables isotopes from carbonates and biogenic material. Magnetic minerals confirm major changes in palaeoenvironmental and palaeohydrological conditions that were deduced from other methods. They also provide complementary information on changes in the lake system during the early and middle Holocene. The most important mineral magnetic change results from the authigenic formation of ferrimagnetic greigite, Fe 3 S 4 during the lacustrine episodes dated from ∼8.7 kyr B.P. to ∼5.5 kyr B.P. (380–335 cm) and from ∼4.5 kyr B.P. to ∼3.5 kyr B.P. (320–285 cm) respectively. Our data also indicate an abrupt break in sedimentary conditions which coincides with a short‐term return towards dry climatic conditions around 3.5 kyr B.P., which was only suggested from other proxy data

Magnetic properties of sediments applied to observation of hydrological and environmental conditions in late Pleistocene and Holocene lake sediments, Lake Faguibine, Mali.

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Some magnetic properties of sediments from lake Fertő (Neudsiedlersee) region, Austia-Hungary

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Near-surface resolution power of the Schlumberger sounding method: examples from the lake Fertő (Neusiedlersee) region, Austria-Hungary

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