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Reconstruction of landscape and climatic conditions of the last interglacial-glacial macrocycle in north-eastern Siberia based on palynological studies of mammoth fauna remainsтезисы доклада
- Автор: Borisova O.
- Сборник: PAGES 2025 Abstract Book. 7th Open Science Meeting "Earth System Changes from the Past towards the Future", 21-24 May 2025, Shanghai, China
- Тезисы
- Год издания: 2025
- Место издания: Shanghai, China
- Первая страница: 346
- Последняя страница: 348
- Аннотация: Palynological studies of sediments filling the bone remains of mammoth fauna animals provide a new source of paleoecological information. Pollen analysis was carried out on samples of sediment extracted from the roots of a Mammuthus primigenius tooth found near the coast of the East Siberian Sea (ca. 70°N, 155°E), where modern vegetation is represented by grass-shrub and moss tundra with rare dwarf birches and willows. The composition of the pollen spectra shows that at the time of the animal's burial, this territory was covered with larch-birch forests with an undergrowth of shrubby alder, birch, willow and dwarf pine, wet meadows and swamps. Finds of pollen from aquatic plants and algae indicate sediment accumulation on the lake's margin. Analysis of modern ranges of fossil flora species shows that the mean July temperature was at least 8°C higher than today. Therefore, the time of the mammoth habitation corresponds to the Last Interglacial (MIS 5e).Palynological studies of sediments filling the brain cavities of two skulls of cave lions (Panthera spelaea) and one skull of a woolly rhinoceros (Coelodonta antiquitatis) found in the middle reaches of the Indigirka River (ca. 68°30’N, 146°20’E) were also carried out. At present, the area is occupied by open larch forest. The northern tree line formed by Larix dahurica crosses the Indigirka River basin at 70°N. The radiocarbon age of the cave lion scull F-4304 (>48,800 yr BP, IGAN-7601) is beyond the limits of the method. The pollen assemblage indicates the development of larch forests with shrub willow, birch and alder in the undergrowth, with a wide distribution of meadows and sedge-grass mires in the depressions. The abundance of microscopic fragments of coniferous wood in this sample suggests that the site is close to a larch copse. The high content of Artemisia pollen indicates the presence of cryoxerotic communities similar to the modern cold steppes of Yakutia. These features point to a more continental and drier climate with higher summer temperatures compared to the modern climate in MIS 3. The relatively high Larix pollen content and the presence of larch stomata in the woolly rhinoceros scull sample F-61 support the significant role of larch in the vegetation during MIS 3. The skull of cave lion F-4302 has been radiocarbon dated to 20,130±60 yr BP (IGAN-7599). The predominance of pollen from dwarf birch and other shrubs, rare finds of larch and tree birch pollen in the sediment filling this skull indicate vegetation similar to the southern tundra, but with a complex mosaic structure combining forest, shrub, tundra, meadow, mire, and cryoxerotic "tundra-steppe" communities. The greater proportion of the latter compared to MIS 3 can be explained by the greater continentality of the climate and the significant decrease in temperatures, especially in winter, due to lower sea levels and a greater width of exposed shelf during the Last Glacial Maximum.
- Добавил в систему: Борисова Ольга Кимовна