P. P. Letunova

Pliocene-Quaternary Vegetation and Climate History of the Lake Baikal Area, Eastern Siberia

A palynological study was carried out on the BDP-96 hole 1 core. We distinguished six major large stages (Al-6) characterized by vegetation changes in the Lake Baikal catchment area. The existence of the most abundant amount of pollen, Tsuga, is a specific feature of the pollen spectra of stage A6 from 3.1 to 2.6Ma.The pollen complex of dark coniferous arboreal plants such as Tsuga, Abies, and Picea, which are sensitive to air humidity, serves as an indicator of the amelioration of climatic conditions. There is a process of replacement of Tsuga pollen by Abies in the pollen spectra of stage A5. The age of this stage was determined to be from 2.6 to 2.35Ma. These are the first reliable palaeobotanical data obtained from continuous cross sections, which reflect the response of regional vegetation and flora to the first well-known significant cooling in the northern hemisphere—the Praetiglian. During stage A4 larch appears and is widely distributed. This is probably connected with the start of a temporary cold continental, climate. At the beginning of stage A3, about 1.85Ma, a new amelioration of climatic conditions takes place. The beginning of stage A2, about 1.5Ma, was characterized by an abrupt change in the composition of regional vegetation and flora. Tsuga disappears from the flora composition, and Larix and Betula are again widely distributed. Pinus pumila appears, and continues to exist. During stage Al, vegetation which was similar to that of the present started to persist in the region, and the climate became sharply continental, and moderately cold

First data on the environment and climate change within the Zhom-Bolok volcanic field (Eastern Sayan Mountains) in the Middle–Late Holocene

This paper considers the results of comprehensive lithological, biostratigraphic, and geochemical investigation of sediments in Khara-Nur Lake (Eastern Sayan Mountains) situated in the area of the greatest Holocene eruptions in the Central Asia Region. The age of the basal sediment layer is estimated at 6881 ± 53 years. The local natural environment and climate have undergone great changes since that time. The Holocene volcanic events did not exert a catastrophic impact on the regional landscape, but they caused dramatic changes in the local vegetation. The well-defined correlation of the regional events with the well-known records of the natural environment in the Northern Hemisphere is indicative of the decisive influence of global atmospheric circulation on restructuring the landscape and climate system in the Zhom-Bolok Region in the Middle–Late Holocene.