Climate and lake development history in the south of West Siberia

Аннотация

There is a huge number of small lakes in south of West Siberia and such lakes are very useful local for climate and environmental reconstructions. The previously studied objects in the area are mostly peat-bogs and geologic sections; the lake history and natural interactions between paleoenvironmental and climate changes in the region are understudied. Here we present results of multiproxy investigation of three lakes located in different parts of the Baraba forest-steppe region along a 300km north-south transect: Bolshie Toroki, Chany (Yarkov subbasin), and Malye Chany. Vibrational drilling technology method was used to recover undisturbed columns of lake sediments and penetrate to non-lacustrine substrata. The obtained cores were investigated basically by sedimentological and palynological analyses (with the reconstruction of vegetational cover) and radiocarbon dating, additionally we used other paleontological (diatom, ostracod, chironomid analyses), geophysical, and biogeochemical methods to obtain information about environmental and climate changes, as well as lake level, biotic, ecosystem, and geochemical changes. This and our previous studies showed complicated picture of lake evolution histories and climate change in the south of West Siberia. According to our data most of investigated lakes (Chany, Malye Chany, Beloye, Minzelinskoye, Bolshie Toroki, and Kirek) are very young and started to form in the middle Holocene or later as marshy lowland with peaty sediments. Then they became deeper with mostly sapropel sediments.