Reconstruction of the Late Holocene environments in the northern Minusinsk Basin (South Siberia) based on the palynological analysis of Lake Shira sediments

Abstract

We present the results of a multiproxy study of a 144 cm long core of laminated sediments from Lake Shira in the northern Minusinsk Basin in order to understand the causal relationships between climate change, ecological responses, and hydrological variations. The new palynological record covers the last 2980 years with an average resolution of 21 years. Palynological results and biome scores indicate that steppe and meadow-steppe with sparse forests prevailed in the northern Minusinsk Basin during the Late Holocene. The lower part of the taiga belt in the mountainous frame of the basin was dominated by larch, and the middle part of the taiga belt was dominated by larch, pine, fir, and spruce. The gradually decreasing role of dark conifers indicates a regional trend towards climatic aridification in the Late Holocene. The ratio of Artemisia pollen to Chenopodiaceae pollen suggests that the semiarid climate of the northern Minusinsk Basin during the last 2980 years was repeatedly interrupted by short intervals of more humid climate. The low abundance of Botryococcus in the records from Lake Shira may be an indicator of lowered lake levels during the intervals of lake holomictic state ca. 2850–2800, 2000–1920 BP, 1320–1290 BP, 700–510 BP, and 120–70 BP. Comparison of new environmental records of the northern Minusinsk Basin obtained from Lake Shira with data on global climate fluctuations shows that changes in the regional vegetation and hydroclimate of Lake Shira in the Late Holocene were mainly caused by large-scale atmospheric circulation processes controlling the heat and moisture balance in South Siberia.