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1)
Аll-Russia
Institute of Geology and Mineral Resources of World Ocean (VNIIOkeangeologia),
St. Petersburg, Russia gus-evgeny@yandex.ru 2) Arctic and Antarctic Research Institute (AARI),
St. Petersburg, Russia, 3) Polyarnouralgeologia Co., Vorkuta, Russia, 4) Marine Arctic Geological Prospecting Expedition (MAGE),
Murmansk, Russia, 5) Polar Marine Geological Prospecting Expedition (PMGRE),
Lomonosov, Russia;
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Directed by the national program of
geological mapping of the shelf to the scale of 1:1,000,000, as well as
in the framework of international research projects, VNIIOkeangeologia
in co-operation with other scientific and industrial institutions has
for 10 years been investigating the Russian Arctic Shelf. In particular,
studied were the shelf zones of Barents Sea, Kara Sea, Laptevs' Sea and
Chukchi Sea, the archipelagos Grumant (also known as Svalbard, or
Spitsbergen), Franz-Joseph Land, Novaya Zemlya, and also the adjacent
parts of the dry land, Bolshezemelskaya Tundra and the Yenissei Estuary.
The results will be partly incorporated in the new generalized map of
Quaternary Deposits of the Russian Shelf that aims to demonstrate the
characteristic features of composition, genesis, and occurrence of
marine, glaciomarine, and glacial deposits, as well as general
distribution of subaerial and subaqueous facies. The wide range of
methods used and vast regional coverage make it possible now to more
confidently approach the Quaternary evolution of Arctic Shelf in general
and of its parts. The Russian Arctic Shelf may be divided into two sectors, the western and
the eastern ones, that differ fundamentally by their Quaternary
evolution. They are divided by a line running east of the Severnaya
Zemlya Archipelago, in the Starokadomsky Trough. The deep-water western
sector has diverse floor topography, and is characterized by vigorous
neotectonic movements, which have been repeatedly bringing it above sea
level. That led to its further erosional dissection and to the facies
diversity. Abundant marginal forms and glacial to glaciofluvial
depositional assemblages left by a number of glaciations, are endemic to
the western sector. Although the mapping of the marginal forms of
different age suggests a limited extent of Quaternary glaciers within
the elevated areas of the nowadays shelf. The eastern sector is considerably shallower and more leveled. Its main
peculiarity is the total lack of evidence of glacial activity.
Quaternary glaciations in Siberia and Chukotka are thought to have been
confined to the mountainous terrains. Neotectonics also plays only a
minor role here. A common feature of both sectors is development of
permafrost on dry lands abandoned by the sea in the Late Pleistocene.
The subsequent submergence of these areas led to partial melting of
subterraneous ice, although its remnants were found by drilling in the
Barents, Kara, and Laptevs' seas, and are expected in the East Siberian
Sea. No evidence of submerged permafrost has been found in the Chukchi
Sea.
The obtained geological and geophysical data help to optimize the
regional stratigraphic schemes, suggest new insights into debatable
issues, and foster new research of Quaternary evolution of the Arctic. |
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Reference:
Gusev E.A., Rekant P.V., Anokhin V.M., Bolshiyanov D.Yu., Zarkhidze D.V.,
Shkarubo S.I., Sharin V.V., Dymov V.A. |
