Pollen-based climate changes since the middle MIS 3 in Jilantai Salt Lake in the marginal region of the Asian summer monsoon domain, Inner Mongolia, China

Abstract

• The pollen record since mid-MIS 3 was provided for a current-hyperarid region of China. • The climate was subhumid during the mid-late MIS 3 and hyperarid during the Holocene . • Insolation and ice volume were the forcing mechanisms for climate changes in the Jilantai Basin. The climate conditions of the marginal region of the Asian summer monsoon (ASM) domain during Marine isotope stage (MIS) 3 (60–27 cal kyr BP) are poorly understood and require further study. Here, we collected fossil pollen samples from a 24.0-m-long drill core from Jilantai Salt Lake (Inner Mongolia, China) to reconstruct the regional climate changes since mid-MIS 3. During 47.0–43.0 cal kyr BP, the frequencies of the occurrence of aquatics and Pediastrum indicate relatively humid conditions. At approximately 43.0 cal kyr BP, the climate became dry, as revealed by the increase in Ephedra and the reduced aquatics and Pediastrum concentrations. The climate during 43.0–27.1 cal kyr BP was drier than that in the previous interval. Aquatics, ferns, and algae were barely detectable, indicating harsh climate conditions during 27.1–12.2 cal kyr BP. During the Holocene, aquatics and algae vanished, and the observed pollen assemblages were dominated by herb taxa; however, a substantial loss of taxa numbers occurred, suggesting that the climate was hyperarid. In general, the climate was relatively humid during the mid-late MIS 3, arid during MIS 2 (27.0–11.7 cal kyr BP), and hyperarid during the Holocene. The evaporation capacity connected with the Northern Hemisphere summer insolation and the Northern Hemisphere ice volume may have played a vital role in vegetation and climate changes in the Jilantai Basin since mid-MIS 3.