Holocene climate background for lake evolution in the Badain Jaran Desert of northwestern China revealed by proxies from calcareous root tubes

Abstract

It has been unclear whether Holocene lake evolution in the Badain Jaran Desert of northwestern China, an area in which lakes are mainly recharged by groundwater, responded to climate change. In this study, we analyzed the Mg/Ca ratio and phytolith assemblages from 10 Holocene calcareous root tube samples from the desert to reconstruct changes in effective moisture and mean annual precipitation (MAP) at the millennial scale during the Holocene and to explore the factors affecting lake evolution. Our results revealed that the effective moisture at 7000–5000 cal yr BP was higher than that of 5000–2000 cal yr BP. Similarly, the MAP was higher at 7000–5000 cal yr BP (175 ± 37 to 205 ± 37 mm) than at 5000–2000 cal yr BP (145 ± 37 to 165 ± 39 mm). The expansion of the lakes during the Early Holocene would have resulted from the input of groundwater from the meltwater in the recharge area. High lake levels in the Middle Holocene corresponded to increased monsoonal precipitation and groundwater recharge. The gradual decline of lake levels in the Late Holocene indicated a relatively arid climate with decreased monsoonal precipitation and groundwater recharge.

Desertification and Related Climate Change in the Alashan Plateau since the Last 40 ka of the Last Glacial Period

“…The ancient shoreline of Yinderertu Lake also suggested that the lake was at a high water level at the end of the last glacial period (Table 1). By establishing a water balance and energy balance model [42], calculated that the precipitation in the hinterland of the Badanjilin Desert during the 31 cal ka period was about 260 mm, which was higher than the modern precipitation in this area. However, it was not always arid during the last glacial period because no organic matter was found during the period of 18.6 to 12.8 ka BP in the Badanjilin Desert [3], suggesting an arid environment during this period.…”

“…Chen F. et al (2003) [9] showed that the climate here was warm and dry in the early Holocene, cold and wet in the middle period, and arid conditions increased in the late period. Li Z (2012) [42] studied the 14 C dating of 16 root canals in the Tenggeli Desert and found that most of these root canals were formed in the mid-Holocene, indicating wet conditions during this period. However, another study by Chen F et al (2006) [48] showed the completely opposite result: the climate was arid at 7.1~3.8 cal ka BP during the mid-Holocene, and the climate was wetter during the early and late Holocene.…”