ORIGIN OF CARBONATE MATERIALS IN THE NORTHERN BASIN OF LAKE BAIKAL AND ITS RELATIONSHIP TO HOLOCENE PALEOCLIMATE

Fine-grained disseminated carbonate was found in Holocene sediments in a core taken from the northern basin of Lake Baikal. The core had two distinct facies. a terrigenous blue-clay overlain by a diatomaceous silt. Oxygen and carbon stable isotope analyses, combined with SEM , X-ray diffraction and .palynology, show that the carbonate in the blue-clay layer is pedogenic in origin, rather than biogenic or authigenic . The S C values in the blue clay suggest that the carbonate is derived from a single source , while the carbonate in the diatom-rich layer might be transported by winds from different sources. On the assumption that the carbonate was formed during the post-glacial age and was transported primarily by river runoff, the 18O isotopic values suggest that the annual temperature in the northern Baikal drainage area was about 3℃ warmer during the middle Holocene (8500-7000 a, B. P.) than during the early Holocene (11 000-8 500a, B.P.) when the blue clay was being deposited . This interpretation is

Origin of carbonate materials in the northern Basin of Lake Baikal and its relationship to holocene paleoclimate

Fine-grained disseminated carbonate was found in Holocene sediments in a core taken from the northern basin of Lake Baikal. The core had two distinct facies, a terrigenous blue-clay overlain by a diatomaceous silt. Oxygen and carbon stable isotope analyses, combined with SEM, X-ray diffraction and palynology, show that the carbonate in the blue-clay layer is pedogenic in origin, rather than biogenic or authigenic. The δ¹³C values in the blue clay suggest that the carbonate is derived from a single source, while the carbonate in the diatom-rich layer might be transported by winds from different sources. On the assumption that the carbonate was formed during the post-glacial age and was transported primarily by river runoff, the δ¹⁸O isotopic values suggest that the annual temperature in the northern Baikal drainage area was about 3°C warmer during the middle. Holocene (8500–7000 a, B. P.) than during the early Holocene (11000–8500a, B. P.) when the blue clay was being deposited. This interpretation, is consistent with the dominant vegetation consisting of grasses in the northern Baikal drainage area prior to 7000a, B. P.,