The upper Pleistocene loess-palaeosol sequence at solonovka on the Cis-Altai plain, west Siberia – First luminescence dating results

Autor: O.A. Meshcheryakova, N.E. Volvakh, R.N. Kurbanov, V.S. Zykina, V.S. Zykin, A.S. Murray, A.O. Volvakh, D.G. Malikov, J.-P. Buylaert
Rok vydání: 2022
Předmět:
Zdroj: Meshcheryakova, O A, Volvakh, N E, Kurbanov, R N, Zykina, V S, Zykin, V S, Murray, A S, Volvakh, A O, Malikov, D G & Buylaert, J P 2022, ' The upper Pleistocene loess-palaeosol sequence at solonovka on the Cis-Altai plain, west Siberia – First luminescence dating results ', Quaternary Geochronology, vol. 73, 101384 . https://doi.org/10.1016/j.quageo.2022.101384
ISSN: 1871-1014
DOI: 10.1016/j.quageo.2022.101384
Popis: Loess-palaeosol deposits of the Upper Pleistocene cover an extensive territory in the south of Western Siberia. Previously, most studies of loess-palaeosol sequences were carried out on river bank sections of the Ob river around Novosibirsk and upstream of this location (Ob Loess plateau); more recently, the focus of research has shifted towards the inner part of the Cis-Altai plain. Despite a good knowledge of the structure of regional loess-palaeosol sequences, there is a considerable lack of absolute dating beyond the radiocarbon limit. However, recent high resolution luminescence dating of a key Marine Isotope Stage 5 (MIS 5) stratotype at Lozhok has identified the presence of a long hiatus in the deposit. As a result, the published ages of the main units have been underestimated, because the existing chronology is largely based on palaeosol counting. This new observation argues for an urgent re-evaluation of the accepted chronostratigraphy of Western Siberian Late Quaternary. Here we present the first luminescence data for a loess-palaeosol sequence of the Cis-Altai plain, at the Solonovka key section, using both quartz optically stimulated luminescence and feldspar post-infrared infrared stimulated luminescence from 25 samples. The results show that the deposits were formed during the Late Pleistocene. The ∼1 m thick well-developed upper pedocomplex (PC1) has cryoturbation cracks filled with upper loess; this a characteristic regional benchmark for stratigraphic correlation. Two distinct hiatuses in sedimentation are found in the section: at the boundary of MIS 3/2, and after the formation of the MIS 5 Berdsk pedocomplex (PC3 and 2) until the beginning of the formation of MIS 3 deposits. The age of the thick PC3 palaeosol at the base of the section is determined as MIS 5, confirming evidence for the pronounced Kazantsevo (Eemian) interglacial in the loess-palaeosol record of Western Siberia. The results of our study emphasize the importance of understanding the palaeogeomorphological background to soil development, and the necessity of absolute chronology; we consider that the position of MIS 5 in the regional chronostratigraphic chart of South Western Siberia requires further study.
Databáze: OpenAIRE
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