High-resolution MIS 11 record from the continental sedimentary archive of Lake Baikal

Abstract

The sedimentary record of Lake Baikal reveals details about the climatic response of continental Asia during the interval 423-362 Ka BP, corresponding to marine oxygen isotope stage MIS 11. The MIS 11 record in Lake Baikal is marked by two plateaus of high biogenic silica content corresponding to MIS 11.3 and 11.2. The middle part of MIS 11 (substage 11.2) exhibits the highest biogenic silica accumulation, reflecting the warmest regional climate, of the last 450 Ka. These interglacial conditions in continental Asia were uninterrupted for about 32 Ka, making MIS 11 the longest interglacial in Siberia, greatly exceeding the duration of interglacial conditions during MIS 5e, 7e and 9e. This extremely long and warm interglacial period of MIS 11.3-11.2 in Siberia ended abruptly with dramatic cooling at 394-390 Ka BP. This cooling resulted in brief mountain glaciation in Siberia due to the amplified response of continental Asia to insolation forcing. The cooling during MIS 11 produced irreversible change in the climate of continental Asia as suggested by diatom succession and by biogenic silica accumulation. Diatom species composition further reveals more complex structure of MIS 11 and makes a strong case for insolation control of diatom production in Lake Baikal.