Vegetation and climate variability during the Last Interglacial evidenced in the pollen record from Lake Baikal

• Published in: Global and Planetary Change
• Main Authors: Granoszewski, W., Demske, D., Nita, M., Heumann, G., Andreev, Andrei
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2005
• Subjects: Kazantsevo; Zyryanka; taiga
• Online Access: https://epic.awi.de/id/eprint/10652/; https://epic.awi.de/id/eprint/10652/1/Gra2004a.pdf; https://doi.org/10.1016/j.gloplacha.2004.09.017; https://hdl.handle.net/10013/epic.21122; https://hdl.handle.net/10013/epic.21122.d001

A high-resolution pollen record from the core sediments collected in the northern part of Lake Baikal represents the latest stage of the Taz (Saale) Glaciation, Kazantsevo (Eemian) Interglacial (namely the Last Interglacial), and the earliest stage of the Zyryanka (Weichselian) Glaciation. According to the palaeomagnetic-based age model applied to the core, the Last Interglacial in the Lake Baikal record lasted about 10.6 kyrs from 128 kyr to 117.4 kyr BP, being more or less synchronous with the Marine Isotope Stage 5e. The reconstructed changes in the south Siberian vegetation and climate are following. A major spread of shrub alder (Duschekia fruticosa = Alnus fruticosa) and shrub birches (Betula sect. Nanae/Fruticosae) in the study area was a characteristic feature during the late glacial phase of the Taz Glaciation. Boreal trees e.g. spruce (Picea obovata) and birch (Betula sect. Albae) started to play an important role in the regional vegetation with the onset of the interglacial conditions. Optimal conditions for Abies sibirica-Picea obovata taiga development occurred ca. 126.3 kyr BP. The maximum spread of birch forest-steppe communities took place at the low altitudes ca. 126.5-125.5 kyr BP and Pinus sylvestris started to form forests in the northern Baikal area after ca. 124.4 kyr BP. Re-expansion of the steppe communities, as well as shrubby alder and willow communities and the disappearance of forest vegetation occurred at about 117.4 kyr BP, suggesting the end of the interglacial succession. The changes in the pollen assemblages recorded in the sediments from northern Baikal point to a certain instability of the interglacial climate. Three phases of climate deterioration have been distinguished: 126-125.5, 121.5-120, and 119.5-119 kyr BP. The penultimate cooling signal may be correlated with the cool oscillation recorded in European pollen records. However, such far distant correlation requires more careful investigation.