High-time resolution AMS 14C data sets for Lake Baikal and Lake Hovsgol sediment cores: Changes in radiocarbon age and sedimentation rates during the transition from the last glacial to the Holocene

High-time resolution C-14 dating of Lake Baikal sediment cores indicates negative and positive anomalies of calculated linear sedimentation rate (LSR; 1.1 and 35.6 cm/ka, respectively) during the period of climate transition from the last glacial to Holocene. The timing of the Lake Baikal apparent LSR anomalies is consistent with that of the changes in the atmospheric radiocarbon concentration (Delta C-14) during Younger Dryas rapid cooling event. C-14 dating of lipids in the Lake Baikal surface sediments revealed that the sources of sedimentary lipids were different in each basin. In the Northern Basin of Lake Baikal, the C-14 age of total lipids from the surface sediment (4.0 C-14 ka) was found to be older than that of TOC (1.6 (14) C ka). By contrast, the C-14 age of total lipids in the Southern Basin was younger than that of the TOC by ca. 0.7-3.0 ka. In the Lake Hovsgol sediment cores, ages of the main lithologic boundaries during the last glacial-interglacial transition were estimated based on new C-14 data sets. TOC concentration in the cores started to rapidly increase at 13.8 +/- 0.3 C-14 ka at the base of the basinwide finely laminated layer deposited during Bolling/Allerod. The base of the layer diatomaceous mud corresponds to the end of Younger Dryas event (10.6 +/- 0.1 C-14 ka). (C) 2009 Elsevier Ltd and INQUA All rights reserved.