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Last Interglacial environments in the White Sea Region based on pollen and aquatic palynomorphs records (Bychye sectionстатья
Дата последнего поиска статьи во внешних источниках: 26 сентября 2016 г.
- Автор: Olga Rudenko
- Журнал: Quaternary International
- Том: 279
- Год издания: 2012
- Издательство: Pergamon Press Ltd.
- Местоположение издательства: United Kingdom
- Первая страница: 416
- Последняя страница: 416
- Аннотация: Vegetation changes and past marine environments in the northeastern White Sea region are reconstructed through a detailed study of both pollen and aquatic palynomorphs in Bychye sediment sequence (Pyoza River), where marine Eemian beds directly overlie Saalian till. The main trend in the evolution of vegetation cover is the gradual supplanting of the late Saalian - earliest Eemian arctic-type periglacial treeless vegetation by birch and light-coniferous forests during early Eemian, and postdated expansion of dark-needled taiga with the strong admixture of thermophylic broadleaved plants (Quercus, Ulmus, Corylus, Carpinus) in mid-late Eemian. Birch prevailed over pine and hornbeam during the final phase of the late Eemian climatic deterioration traced by the disappearance of spruce, alder and other mesophyllous representatives among forbs. The abundance of freshwater chlorococcalean algae Botryococcus cf. braunii in the basal part of marine clays right above the moraine indicates significant influence of the local river runoff during early stage of inundation. Dinocyst assemblage dominated by heterotrophic species Islandinium minutum reflects harsh and severe marine conditions with heavy seasonal sea-ice cover during late Saalian - earliest Eemian times. No direct indicators, such as Operculodinium centrocarpum, of Atlantic water penetration to the White Sea region were observed in dinocyst assemblages. However, the occurrence of autotrophic species of Penthapharsodinium dalei, Spiniferites cf. pachydermus and, especially, Nematosphaeropsis labyrintus in the middle part of the section indicates more saline and warm water conditions during the optimal phase of the Eemian.
- Добавил в систему: Руденко Ольга Владимировна