A reassessment of late glacial - Holocene diatom oxygen isotope record from Lake Baikal using a geochemical mass-balance approach

We present a new palaeoenvironmental record of hydrological variability in Lake Baikal, based on re-modelled delta O-18(diatom) values of diatom silica (delta O-18(modelled)), where the residual contaminants are identified and compensated for using electron optical imaging and whole-sample geochemistry. delta O-18(modelled) interpretations are based on the balance between rivers with high delta O-18 values and rivers with low delta O-18 values. Isotopic variability is related to latitudinal differences in precipitation which feed these rivers. The delta O-18(modelled) record suggests that rather moist conditions prevailed in the Lake Baikal region during the latter stages of the Younger Dryas. Throughout the Holocene, episodes of low delta O-18(modelled) values are, in general, in good agreement with increases in percentage haematite-stained grains in North Atlantic sediments (indicative of ice-rafted debris events). Rivers with southerly catchments dominate fluvial input especially between c. 3.3 and 2 cal ka BP, concurrent with high precipitation in the Lake Baikal region. Copyright (C) 2011 John Wiley & Sons, Ltd.