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Within the framework of the Baikal Drilling Project (BDP), a 192 m long sediment core (BDP-96-1) was recovered from the Academician Ridge, a submerged topographic high between the North and Central Basins of Lake Baikal. Sedimentological, clay mineralogical and geochemical investigations were carried out on the core interval between 90 and 124 m depth, corresponding to ca. 2.4–3.4 Ma. The aim was to reconstruct the climatic and tectonic history of the continental region during the intensification of Northern Hemisphere glaciation in Late Pliocene time. A major climate change occurred in the Lake Baikal area at about 2.65 Ma. Enhanced physical weathering in the catchment, mirrored in the illite to smectite ratio, and temporarily reduced bioproduction in the lake, reflected by the diatom abundance, evidence a change towards a colder and more arid climate, probably associated with an intensification of the Siberian High.
Two boreholes, one to a depth of 300 m, and the other to a depth of 100 m below sediment surface were drilled at 53°41´48´´N-108°21´06´´E. The core was collected down to 200m in the first borehole, and totally in the second one. Yield of the cores was more than 95%. Sediments consist of terrigenic and biogenic silts. All along the section, clay layers alternate with layers of diatomaceous silt. Studies of the section revealed that sediments accumulated under deep water during all the period of their deposition; no hiatuses or unconformities were found. Studies done in Russia, USA, Japan and Germany gave results that are consistent with each other. Correlation of magnetic properties with the palaeomagnetic scale revealed that the age of sediment at 200 m is 5 My. Mean sediment accumulation rate was constant and equaled 4 cm per 1 ky, Rhythmic structure of the sediments consisting of layers of diatom-barren clays and diatomaceous silts is due to cyclic changes of cold and warm climates.