Desert evolution and climatic changes in the Tarim River basin since 12 ka BP

Climatic changes in the Tarim River basin since 12 kaBP were divided into four stages based on the analy ses of sedimentary phase, the features of some climatic and environmental biomarks in the sedimentary strata and desert evolution. During the Holocene, cool-dry and temperate-dry climates resulted in apparent alluvial-fluvial and weak aeolian activities. During 10-8 kaBP, the climate was dry and cold, large-scale sand dunes activities led to regional desert expansion. During the hypsithermal (8-3 kaBP), the climate was dry and warm, shifting sand areas decreased and a lot of sand dunes were fixed along the banks of the Tarim River and its tributaries, lowlands and lakes. As a result, fluvial-alluvial areas increased. Since 3 kaBP, the aeolian activity and sandstorms have been enhancing due to the combined influences of climatic warming and illogical exploitation of land and water resources. The climate in the Tarim River basin have been persistently dry and alternated by warm and cold periods. Consequently, the sedimentary environments have varied from desert steppe to desert, and strongly influenced by periphery mountains and global climatic fluctuations.