Paleogeography and geochronology in the Russian eastern Arctic during the second half of the quaternary

Alekseev, M.N.

doi:10.1016/s1040-6182(96)00031-6

Cited by 26 publications

(23 citation statements)

References 1 publication

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“…The Bykovsky record also sheds some light on the unsolved problem of the supposed ''Karginskian marine transgression''. Some researchers believe that the sea level in the Laptev shelf area in the Middle Weichselian was much higher than in the Early and Late Weichselian, and actually was close to the modern level, or even slightly higher than today (Alekseev, 1997;Fedorov and Bolshiyanov, 2002). While some evidence in support of the ''Karginskian transgression'' does exist in the North Siberian Lowland (SW of Taimyr) (Andreeva et al, 1982), for the Laptev Sea area such evidence is very vague.…”

Section: The Middle Weichselian and The ''Karginsky Interglacial'' Prmentioning

confidence: 95%

“…Was the climate milder and vegetation richer in the Middle Weichselian (MIS 3) than today? Some researchers believe they were, and reconstruct shrub tundra (Alekseev, 1997) or even taiga forest (Igarashi et al, 1995) on the shelf land; they traditionally describe this period as a relatively warm ''Karginskian Interstadial''. Other students suggest that the vegetation of that time did not differ much from herb-dominated tundra or tundra-steppe of the ''glacial'' intervals; it should be noted, however, that real evidence is very poor and scattered (cf.…”

Section: Introductionmentioning

confidence: 99%

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New insights into the Weichselian environment and climate of the East Siberian Arctic, derived from fossil insects, plants, and mammals

Sher

Kuzmina

Кузнецова

et al. 2005

Quaternary Science Reviews

244

226

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Multidisciplinary study of a key section on the Laptev Sea Coast (Bykovsky Peninsula, east Lena Delta) in 1998-2001 provides the most complete record of Middle and Late Weichselian environments in the East Siberian Arctic. The 40-m high Mamontovy Khayata cliff is a typical Ice Complex section built of icy silts with a network of large syngenetic polygonal ice wedges, and is richly fossiliferous. In combination with pollen, plant macrofossil and mammal fossils, a sequence of ca 70 insect samples provides a new interpretation of the environment and climate of the area between ca 50 and 12 ka. The large number of radiocarbon dates from the section, together with an extensive 14 C database on mammal bones, allows chronological correlation of the various proxies. The Bykovsky record shows how climate change, and the Last Glacial Maximum in particular, affected terrestrial organisms such as insects and large grazing mammals. Both during the presumed ''Karginsky Interstadial'' (MIS 3) and the Sartanian Glacial (MIS 2), the vegetation remained a mosaic arctic grassland with relatively high diversity of grasses and herbs and dominance of xeric habitats: the tundra-steppe type. This biome was supported by a constantly very continental climate, caused by low sea level and enormous extension of shelf land. Variations within the broad pattern were caused mainly by fluctuations in summer temperature, related to global trends but overprinted by the effect of continentality. No major changes in humidity were observed nor were advances of modern-type forest or forest-tundra recorded, suggesting a major revision of the ''Karginsky Interstadial'' paradigm. The changing subtypes of the tundra-steppe environment were persistently favourable for mammalian grazers, which inhabited the shelf lowlands throughout the studied period. Mammal population numbers were lowered during the LGM, especially toward its end, and then flourished in a short, but impressive peak in the latest Weichselian, just before the collapse of the tundra-steppe biome. Throughout MIS 3 and MIS 2, the climate remained very favourable for the aggradation of permafrost. No events of regional permafrost degradation were observed in the continuous Bykovsky sequence until the very end of the Pleistocene. r

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Section: The Middle Weichselian and The ''Karginsky Interglacial'' Prmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

New insights into the Weichselian environment and climate of the East Siberian Arctic, derived from fossil insects, plants, and mammals

Sher

Kuzmina

Кузнецова

et al. 2005

Quaternary Science Reviews

244

226

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“…2), which are among the widest and shallowest shelf-seas worldwide. Due to their distance from precipitation source areas, they were not affected by large inland glaciations after the Middle Pleistocene (Alekseev, 1997;. NE-Siberian arctic lowlands and shelves were consequently scarcely influenced by glacioisostatic lifts during that time.…”

Section: Geologymentioning

confidence: 99%

“…In arctic Siberia, evidence of Eemian transgressions exists in fact only on the Taymyr and Chukotka Peninsulas (Kind & Leonov, 1982;BrighamGrette et al, 2001). Between the Lena and Kolyma Rivers, Eemian marine deposits were only reported from the northern coast of Kotel'ny Island (Alekseev, 1997). The sequence 8-9 m a.s.l.…”

Section: Coast Line Position and Tectonicsmentioning

confidence: 99%

Continental climate in the East Siberian Arctic during the last interglacial: Implications from palaeobotanical records

Kienast

Tarasov

Schirrmeister

et al. 2008

Global and Planetary Change

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A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 summer temperature was considerably higher, the growing season was longer, and soils outside the range of thermokarst depressions were drier than today. Our pollen-based climatic reconstruction suggests a mean temperature of the warmest month (MTWA) range of 9-14.5 °C during the warmest i nterval of the last interglacial. The reconstruction from plant macrofossils, representing more local environments, reached MTWA values above 12.5 °C in contrast to today's 2.8 °C. We explain this contrast in summer temperature and soil moisture with a combination of summer insolation higher than present and climatic continentality in arctic Yakutia stronger than present as result of a considerably less inundated Laptev Shelf during the last interglacial.

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“…They have a high content of segregated ice and polygonal ice wedges several meters in height and width. These deposits were formed during the Late Pleistocene regression (marine isotope stages 5-3) on the dry Laptev Sea shelf and in the North Siberian lowlands (Soloviev, 1989;Sher, 1995, Alekseev, 1997Romanovskii et al, 2000). Ice Complex deposits in the region are regarded as remnants of a Late Pleistocene accumulation plain (Sher, 1999).…”

Section: Introductionmentioning

confidence: 99%

Late Quaternary sedimentation history of the Lena Delta

Schwamborn

Rachold

Grigoriev

2002

Quaternary International

165

176

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Core and outcrop analysis from Lena mouth deposits have been used to reconstruct the Late Quaternary sedimentation history of the Lena Delta. Sediment properties (heavy mineral composition, grain size characteristics, organic carbon content) and age determinations ( 14 C AMS and IR-OSL) are applied to discriminate the main sedimentary units of the three major geomorphic terraces, which form the delta. The development of the terraces is controlled by complex interactions among the following four factors: (1) Channel migration. According to the distribution of 14 C and IR-OSL age determinations of Lena mouth sediments, the major river runoff direction shifted from the west during marine isotope stages 5-3 (third terrace deposits) towards the northwest during marine isotope stage 2 and transition to stage 1 (second terrace), to the northeast and east during the Holocene (first terrace deposits). (2) Eustasy. Sea level rise from Last Glacial lowstand to the modern sea level position, reached at 6-5 ka BP, resulted in back-filling and flooding of the palaeovalleys. (3) Neotectonics. The extension of the Arctic Mid-Ocean Ridge into the Laptev Sea shelf acted as a halfgraben, showing dilatation movements with different subsidence rates. From the continent side, differential neotectonics with uplift and transpression in the Siberian coast ridges are active. Both likely have influenced river behavior by providing sites for preservation, with uplift, in particular, allowing accumulation of deposits in the second terrace in the western sector. The actual delta setting comprises only the eastern sector of the Lena Delta. (4) Peat formation. Polygenetic formation of icerich peaty sand (''Ice Complex'') was most extensive (7-11 m in thickness) in the southern part of the delta area between 43 and 14 ka BP (third terrace deposits). In recent times, alluvial peat (5-6 m in thickness) is accumulated on top of the deltaic sequences in the eastern sector (first terrace). r

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Paleogeography and geochronology in the Russian eastern Arctic during the second half of the quaternary

Cited by 26 publications

References 1 publication

New insights into the Weichselian environment and climate of the East Siberian Arctic, derived from fossil insects, plants, and mammals

New insights into the Weichselian environment and climate of the East Siberian Arctic, derived from fossil insects, plants, and mammals

Continental climate in the East Siberian Arctic during the last interglacial: Implications from palaeobotanical records

Late Quaternary sedimentation history of the Lena Delta

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