Comprehensive Investigation of Lake Baikal Core 323-Pc1

A piston core (461 cm long) collected at the pelagic site (710 m deep below lake surface) of the north Lake Baikal was comprehensively investigated on many items. This core is divided into two units at the horizon of 140–150 cm which is recognized as the boundary between Holocene and Late Pleistocene by radiocarbon dating. This is consistent with the results of other analytical items and deposition period of lower unit is glacial age (Sartan). Upper unit is mainly of silt-size composition and regarded as diatom gyttja (biogenic silica 20–30%) in which numerous diatom, some microfossils, abundant pollen, high contribution of allochthonous organic matter are found. On the other hand, we found very few diatom, no microfossils, very few pollen, and very little allochthonous organic matter in the lower unit. The drastic change of biomass means that the condition of phytoplanktonic development in northern Lake Baikal had been quite severe in Sartanian age. The impressive change of pollen assemblages and absolute number of pollen grain indicate that present-day taiga and/or broad-leaved mixed forest occurred around the northern Baikal during Holocene, while flora like the present-day tundra was during Sartanian age. These contrast on both flora and fauna on limnetic ecosystem between two units should prove that the core samples in northern Baikal Lake have the high sensitivity for paleoclimatic research.