6 - Palaeoclimatic changes from 3.6 to 2.2 ma b.p. derived from palynological studies on lake baikal sediments

Abstract

The position of Lake Baikal in the interior of the Eurasian continent provides a unique opportunity for reconstructing late Cenozoic vegetation history. Changes in the distribution of northern boreal taiga forests, southern Mongolian steppe elements, and steppe forests have implications for understanding past climatic changes in northeastern Eurasia during the Pliocene and Pleistocene epochs. Late Pliocene environmental changes in the northern hemisphere between 3.5 and 2 Ma BP (million years before present) are of special interest due to records of cooling and aridity between 3.5 and 3.0 Ma and after 2.7 Ma. The palynological record from BDP-96-1 drill cores (Academician Ridge, 321 m water depth) revealed late Pliocene development of mixed coniferous forests with a decline in associated broadleaved trees and hemlocks, followed by the expansion of open vegetation (Artemisia). The vegetation and inferred climate changes in the Baikal region around 2.7 Ma BP (million years before present) are related to the intensification of northern hemisphere glaciations recorded as increases in ice-rafted debris in North Pacific (and North Atlantic) sediments.