C01_P06

Updated radiocarbon age-depth model from Lake Baikal sediment: Implication for past hydrological changes for last glacial to the Holocene

Nara F^1,2,3, Watanabe T⁴, Lougheed B⁵, Obrochta S⁶

¹Nagoya University, Nagoya, Japan, ²Kanazawa University, Kanazawa, Japan, ³Chukyo University, Nagoya, Japan, ⁴Japan Atomic Energy Agency, Gifu, Japan, ⁵Uppsala University, Uppsala, Sweden, ⁶Akita University, Akita, Japan

We present an updated ¹⁴C age model using IntCal20 to calibrated new AMS data applied to a Lake Baikal sediment core (VER99G12) in south Siberia. ¹⁴C measurements showed that the core extends to 32 ka BP. To take into account uncertainties in ¹⁴C age and sedimentation depth in the core, a new age-depth modeling routine, undatable, was used in this study. Undatable revealed that the significant changes in the sedimentation rate correspond to global climate events, either warm or cold, which are the Meltwater pulses (MWP) at 19 and 14 ka BP and the Last glacial maximum (LGM) at 21 - 20 ka BP. Since the Selenga River accounts for 50 % of the total river inflow to Lake Baikal, we interpret that these changes in sedimentation rate could be signals of significant increase in Selenga River discharge to the lake, which is expected to be affected by global climate change. Total organic carbon content and mean grain size increase concurrent with sedimentation rate, suggesting river inflow increased available nutrients for biological activity. Our results indicate that hydrological changes corresponding to MWP events can be observed in continental area of the Northern hemisphere.