A diatom record of centennial resolution for the Kazantsevo Interglacial stage in Lake Baikal (Siberia)

Diatom analysis of a sediment core from the Northern basin of Lake Baikal (Siberia) has been carried out with focus on the Kazantsevo Interglacial period (equivalent to the Eemian in Europe). The age model, based on palaeomagnetism, indicates that this stage lasted about 11,000 years in the region of Lake Baikal, from ca. 128 to 117 ky BP. Diatom data (sampling resolution of 1-cm interval, ca. 130 years), including both relative percentage and biovolume accumulation rate (BVAR) data, are used to infer past limnological conditions and the climatic factors that drove them. Our record reveals that peak interglacial conditions, characterized by highest diatom production, occurred between ∼124 and 120 ky BP. During that period, the diatom record suggests stable, warm and moist conditions. This climatic optimum is then interrupted by a low amplitude cold event at ∼120 ky BP. The last part of the interglacial in Lake Baikal, between ∼120 and ∼117 ky BP, is marked by colder and probably drier climate. Low-resolution diatom analysis spanning the Kazantsevo was also carried out on another core taken further south at Academician Ridge. Diatom successions at the two sites investigated were remarkably similar suggesting that our sedimentary records are complete and representative for at least a large part of Lake Baikal.