Holocene Climate Changes Documented By Lake Sediments From Bosten Lake In Xinjiang

Bosten Lake, the largest inland freshwater lake in China, is strongly influenced by westerly and the climatic changes during the Holocene could be preserved in the lake sediments. We carried out systematic analyses of lacustrine authigenic carbonate (fine carbonate and ostracod shells) on lake sediments from BST04H core. Based on the existing age model of BST04H, we reconstructed the regional climate and the lake status since early Holocene through comprehensive analyses of fine carbonate content, stable-isotopes of fine carbonate and ostracod shells. Compared with proxies from other cores in Bosten Lake by previous researches, our results reached the following conclusions:1. Fine carbonate could represent Lacustrine authigenic carbonate. Oxygen istopes of ostracod shells and fine carbonate is mainly a reflection of the isotopic composition of the host water, which is controlled by the precipitation (input water)/evaporation ratios.2. From 10000～8300 cal yr BP, the climate was dry, Bosten lake expanded and formed at 8300 cal yr BP; During the period 8300～5000 cal yr BP, the lake was in a stable stage, and the lake level was rising slowly; From 5000～3700 cal yr BP, a generally dry climate prevailed in the lake drainage; From 3700～500 cal yr BP, the lake level began to drop after a rapid rise; From 500～-49cal yr BP, the lake expended after a short period of shrink.3. There is consistency in the records from Bosten Lake between BST04H and other cores, and rapid climate changes have been well recorded. Differences between these cores may be due to differences in sampling locations, sample resolution, age models and proxy indicators.