Climate-induced fluctuations of 10Be concentration in Lake Baikal sediments

Sedimentary Be-10 records covering the last 150 kyr were obtained from three cores collected at the Academician Ridge (BDP-96/hole2 core and VER96/st.3 core) and at the Buguldeika Saddle (BDP-93/hole2 core) in Lake Baikal. The Be-10 concentrations of the three cores varied between 0.5 x 10(9) and 1.5 x 10(9) atoms/g, and coincidently dropped at the stratigraphic intervals of marine oxygen isotope stages (MIS) 2, 4, 5d and 6. The depositional fluxes of Be-10, on the other hand, generally rose in those stages having an increase in the dry bulk densities and sediment accumulation rates. These results are consistent with previous work (Horiuchi et al., 1999), suggesting that the dilution effects of low-Be-10-concentration particles principally controlled the fluctuations of the Be-10 concentrations of Lake Baikal sediments. Low-Be-10-concentration particles have been intensively produced by mechanical weathering and physical erosion under the cold and dry climatic conditions during the peak glaciation period, and have been directly brought from the source areas into the lake as a result of the thin vegetative cover of the watershed. (C) 2000 Elsevier Science B.V. All rights reserved.