The Holocene–late Quaternary Record of Sedimentary Organic Matter in Cores From the Academician Ridge, Lake Baikal

The Holocene–late Quaternary record of sedimentary organic matter was determined in cores from the Academician Ridge, Lake Baikal, by analyzing the total carbon and nitrogen contents, and biogenic silica content. Total carbon-to-nitrogen ratios suggest that the sedimentary organic carbon is largely derived from the water column and not transported into the lake from the watershed. Accelerator radiocarbon dating in one core provides an approximate chronology of events affecting the accumulation of organic materials on Academician Ridge for the last 20,000 years. From 20,000 to 14,000 years before present (ybp), generally low biogenic production and high inorganic terrestrial input resulted in low amounts of organic carbon and biogenic silica. During the last 14,000 ybp, biogenic opal and organic carbon increased, especially at 7,500 to 6,500 ybp. The highest mass accumulation rate of organic carbon occurred from 14,500 to 13,000 ybp and was lowest during the period from 5,500 to 1,500 ybp. With further work and calibration, it may be possible that the organic carbon record of Lake Baikal can be used to record changes in atmospheric carbon dioxide concentrations through time.