Geochemical indicators of climate changes in Southwestern Siberia (Russia) in the Holocene sediments of Lake Itkul

Abstract

Abstract. We present the results of study the Holocene sediments of Itkul Lake, a shal low brackish lake with carbonate sedimentation, located in the eastern part of Baraba lowland (Southwestern Siberia, Novosibirsk Region). A 1.8 m thick core of the Holocene (7.9 14C yr) sediments of Itkul Lake has been studied. Based on the geochemical and lithostratigraphic properties of the bottom sediments, we have established the following stages of the lake evolution: (I) the beginning of sedimentation, 7.8 7.0 14 ka; (II) extreme shallowing with a probable complete drying, ~7.0 5.5 14 ka; (III) rise in the water level, ~5.5 4.3 14 ka; (IV) repeated shallowing, 4.3 2.8 14 ka; and (V) subsequent watering, 2.8 0 14 ka. At present, the lake again tends to shallowing.