CENOZOIC DEPOSITS OF THE UNDERWATER AKADEMICHESKII RIDGE IN LAKE BAIKAL

Abstract

This paper presents data on the lithological composition of Cenozoic deposits penetrated for the first time by boreholes BDP-96-1, BDP-96-2, and BDP-98 down to a depth of 600 m on the underwater Akademicheskii Ridge in Lake Baikal. The deposits are subdivided into the upper (Angara) and lower (Barguzin) sequences, which span the Middle Miocene-Holocene period. They formed under different climatic conditions and tectonic settings. Sources of the terrigenous material were also different. Outbursts of diatom-and mineral formation in Lake Baikal can be related to not only climatic fluctuations in the Miocene-Holocene, but also the endogenous activity. By the analogy with the World Ocean, underwater gas-hydrothermal fluid discharge detected at the water-bottom interface in this lake may be accompanied by the formation of diatomaceous oozes and ferromanganese nodule fields and the concentration of rare elements. © Pleiades Publishing, Inc. 2006.