NEW DATA ON THE GENESIS AND TIME OF FORMATION OF THE LOW RIDGE (GRIVA) UNIT AND LOW RIDGE (GRIVA) RELIEF OF THE UPPER PLEISTOCENE BARABA PLAIN IN THE SOUTH OF WESTERN SIBERIA
V.S. Zykin1,2, V.S. Zykina1, R.N. Kurbanov3,4, A.O. Volvakh1, N.E. Volvakh1, E.L. Malikova1
1 V.S. Sobolev Institute of Geology and Mineralogy, Sibirian Branch Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
3Institute of Geography, Russian Academy of Sciences, Moscow, Russia
4Lomonosov Moscow State University,Moscow, Russia
Keywords: Quaternary, griva unit, griva relief, aeolian deposits, geochronology, paleosols, OSL dating, Volchia Griva
Abstract
The article examines the structure, composition, and textural features of the griva unit of the Volchia Griva section and the paragenetically associated relief. Additional data on the aeolian origin of the griva unit and griva relief have been obtained. OSL and ICS dating of the Volchya Griva section allowed us to attribute the formation time of the Griva unit to the epoch of the last glaciation and to correlated it with MIS 2 in its entire volume. It has been confirmed that the formation of aeolian relief and the activation of aeolian processes occurred during the cold glacial periods of the late Pleistocene with the predominance of southwesterly winds. The established textural features of the griva unit section are similar in textural and structural characteristics to the niveo-aeolian sands of the Upper Pleistocene, which were formed in cold, periglacial, arid regions of the world and distributed along the southern edge of the ice sheets of the last glaciation from Northwestern Europe to Western Siberia and Alaska. The formation of a deflationary truncation and of a mega-yardangs system in the northern part of the Lake Chany basin indicates a significant activation of aeolian processes at the boundary between the formation of the lower and upper horizons of the griva unit. The orientation of the griva relief, coinciding with the prevailing direction of modern winds, indicates the same direction of winds during the cold and warm epochs of the Quaternary in the south of Western Siberia. The completeness of the structure of the Volchya Griva section, corresponding to the epoch of the last glaciation and MIS 2, the confinement to this section of the largest in Eurasia location of the remains of the mammoth fauna, distinct lithological characteristics, a fairly high degree of its study allow us to consider this section as one of the typical for the Upper Pleistocene of Siberia and to consider it as a stratotype of the griva unit, widespread in this territory, which should be distinguished into an independent Baraba horizon (suite) for the south of Western Siberia, including the Eltsovka and Bagan loesses and the Suma soil separating them
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