Paleoenvironmental changes in the eastern Kumtag Desert, northwestern China since the late Pleistocene

Abstract

Sedimentary records from the Kumtag (also known as Kumtagh) Desert (KMD) in northwestern China are investigated to better understand Late Quaternary paleoenvironmental changes in this hyper-arid region. Presented here are the results of probably the first systematic survey of sedimentary sequences from the KMD, with the chronology determined by the optically stimulated luminescence dating. The variation of sedimentary facies, supported by granular and geochemical paleoenvironmental proxies, is used to decipher the history of Late Quaternary environment changes. The results demonstrate that a constantly dry condition characterized the eastern KMD since the last glacial maximum, but with occurrences of wetter periods. From ca. 17 to 15 ka, fluvial activity was probably triggered by melting of glaciers in mountains located south of the KMD. A distinctly drier stage (ca. 13–7 ka) was recognized due to the prominent occurrence of aeolian sands. A wetter environment likely persisted between ca. 4.4 and 2.2 ka, consistent with evidence of human activities. While the causes of paleoenvironmental changes in the eastern KMD are still a matter of debate, the melting of glaciers in the Altyn-Tagh Mountains in the south must be considered as an important factor.