Mid-to-Late Holocene climate changes on the southern margin of the Badain Jaran Desert: Evidence from the Gaotai Lake sediments

The Gaotai Lake is located on the southern margin of the Badain Jaran Desert. Under the influence of Asia monsoon and westerlies, there preserve reliable records of climatic changes for the Asia’s interior during the Mid-to-Late Holocene. Based on OSL dating and high-resolution multi-proxy records such as carbonate content, color, grain-size end-member (EM) modeling, it is inferred that the lake has experienced four distinct phases of climatic changes during the period from Mid-to-Late Holocene. Our results suggest that it used to be a shallow lake or nearshore environment during 7.1～5.3 ka, under a relatively dry climate condition. During the period of 5.3～1.2 ka, the lake was expanded and reached its highest level. Also, the records of carbonate content and a* and b* indices indicate that precipitation was increased and erosion intensified, representing the wettest period during the time of Mid-to-Late Holocene. In the period of 1.2～0.2 ka, the region changed back to a shallow lake or nearhore environment, and the climate turned to dry again. After 0.2 ka, the lake disappeared and the place is predominated by modern sand dunes under a drier climate. Regional proxy records show that the evolution of the Gaotai Lake is consistent and comparable with the lake records in arid Central Asia, where the climate is mainly affected by the westerlies and the high-latitude North Atlantic Ocean.