پوشش گیاهی و محیط زیست در اواخر دوره قاجاری براساس داده های گرده از جنوب شرقی مغولستان، چین

A late Quaternary pollen record from the Liujiadian section (42°58′58.0″N, 117°26′39.3″E) situated in southeastern Inner Mongolia, spanning the last ca. 35 ka, was used to reconstruct regional vegetation history and climate change. Three stages of vegetation dynamics and climate change are documented in this record. During 35.23 to 25.15 ka, the latter part of Marine Isotope Stage (MIS) 3, a forest-steppe landscape developed under wet conditions dominated the surrounding areas. The following period, 25.15–11.13 ka, approximately corresponding to MIS 2, was characterized by the overall drought conditions superimposing climatic oscillations. During 25.15–22.25 ka, the shift to typical steppe highlighted the drought trend. After 22.25 ka, severe drought conditions led to the invasion of desert-steppe. The modest climatic amelioration, occurred from 18.47 to 16.24 ka, was characterized by the relieving drought, indicated by the replacement of typical steppe. The landscape was defined by the desert-steppe under a dry climate after 16.24 ka and briefly interrupted by the recovering of typical steppe at the end of this interval. The Holocene likely commenced at about 11.13 ka, reflected by the gradual establishing of forest-steppe in a relatively humid climate. Regional comparisons suggest a roughly synchronous pattern of climate change and variations in the East Asian summer monsoon (EASM), attributing to the force of the northern hemisphere summer insolation and ice volume. In addition, the millennial-scale EASM variability has coincided with the Heinrich (H) and Dansgaard–Oeschger (D–O) events, and the Younger Dryas (YD), indicating the plausible linkage to the rapid Atlantic meridional overturning circulation (AMOC) oscillations.