Continental response to Heinrich events and Bond cycles in sedimentary record of Lake Baikal, Siberia

Abstract

The sedimentary core BDP-93-2, Lake Baikal, southeast Siberia, provides a high-resolution record of the interval corresponding to marine oxygen isotope stage 3 (MIS 3). Sharp drops in fossil diatom abundance suggest the occurrence of short-term cooling episodes in Lake Baikal area during this time interval. AMS radiocarbon dates on core BDP-93-2 constrain the age of the upper three episodes (younger than 24 ka BP, younger than 30.5 ka BP, older than 34 ka BP) and therefore permit correlation of the Baikal diatom abundance record with records of iceberg discharge (Heinrich) events in the North Atlantic. Lithology of BDP-93-2 at the Selenga Delta indicates that cooling episodes are also associated with deposition of distinct layers of brownish mud enriched in terrestrial organic carbon. Thus, two types of signals associated with Heinrich events and Bond cooling cycles are observed in the sedimentary record from Lake Baikal. The lacustrine response to cooling episodes includes basin-wide decreases in diatom production, and the response of the catchment basin includes erosion of soils. These episodes of erosion, herein recognized as “Kuzmin events”, are likely related to dramatic changes in atmospheric precipitation regime that impacted the semi-arid provinces of Lake Baikal watershed over the short periods of time represented by these events.