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- Daxner-Höck, Gudrun, et al.
(författare)
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A synthesis of fauna, palaeoenvironments and stratigraphy of the Miocene Tagay locality (Olkhon Island, Lake Baikal, Eastern Siberia)
- 2022
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Ingår i: Palaeobiodiversity and Palaeoenvironments. - : Springer Science and Business Media LLC. - 1867-1594 .- 1867-1608. ; 102:4, s. 969-983
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Tidskriftsartikel (refereegranskat)abstract
- We report about the Early Miocene Tagay fauna of Olkhon Island, the largest island of the Baikal Lake. The Tagay fauna is of high scientific importance because of the diversity of fishes, amphibians, lizards, snakes, turtles, manifold birds and mammals. The lithology, geochemistry and the fossil record along the Tagay-1 section allow reconstruction of various palaeoenvironments, i.e. open water, shallow lakes with adjacent wetlands, riverine woodlands, and also forested and dry habitats. The fossil record, lithology and geochemical sediment-analyses suggest a temperate palaeoclimate with short humid and dry periods. The small mammal record and the magnetic polarity pattern of the upper part of section Tagay-1 correlate with the subchrons C5Cn.2r – C5Cn.1r of Chron C5C and the late Burdigalian Stage of the Geologic Time Scale (GTS2000). The corresponding age range of the Tagay fauna is ~16.5 to ~16.3 Ma.
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- Kazansky, Alexey Yu, et al.
(författare)
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Palaeomagnetic data from the late Cenozoic Tagay section (Olkhon Island, Baikal region, Eastern Siberia)
- 2022
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Ingår i: Palaeobiodiversity and Palaeoenvironments. - : Springer Science and Business Media LLC. - 1867-1594 .- 1867-1608. ; 102:4, s. 943-967
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Tidskriftsartikel (refereegranskat)abstract
- One of the most important fossil fauna localities in the Baikal region is the Tagay section. It is located on the shore of Tagay bay at the northwestern coast of Olkhon Island in the Baikal Lake and consists of two different exposures, Tagay-1 and Tagay-2. The Tagay-1 section exposes predominantly lake sediments of Miocene age and contains a faunal complex. The Tagay-2 section is composed of slope wash and subaerial sediments of Early Pleistocene (Calabrian?) age with remains of small mammals. A total of 95 samples for palaeomagnetic studies were taken in both sections. Magnetic susceptibility (MS), its frequency dependence (Fd) and anisotropy were measured from all samples. The stable component of the natural remanent magnetization (NRM) was obtained using stepwise alternating field (AF) demagnetization. The magnetic polarity pattern was constrained for the Tagay-1 section. It includes an extended zone of reversed polarity, complicated by three normal subzones of minor rank. Palaeontological data allow correlation of the Tagay-1 pattern with the magnetic chrons C5Dn to C5Cn.1n (late Burdigalian – early Langhian). Palaeomagnetic directions in the upper part of the Tagay-2 section are randomly distributed due to intensive slope-wash processes resulted in mechanical perturbation of the sediments. The lower part of Tagay-2 section demonstrates only reversed polarity, although the scatter of directions is quite large due to landsliding. This reversed interval may be correlated with the Matuyama chron between Cobb Mountain and Olduvai subchrons. Synchronous increase of MS and Fd values in palaeosols suggests a pedogenic (or “Chinese”) mechanism influencing magnetic properties of the Tagay-2 section under warm palaeoclimatic conditions.
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