AbstractThe evolution processes and forcing mechanisms of the Horqin dunefield in northern China are poorly understood. In this study, systematic OSL dating of multiple sites is used together with pollen analysis of a representative section in order to reconstruct the evolution of the dunefield since the Last Glacial Maximum (LGM). Our results show that there was extensive dune mobilization 25–10 ka, transition to stabilization 10–8 ka, considerable dune stabilization 8–3 ka, and multiple episodes of stabilization and mobilization after 3 ka. Comparison of dune evolution of the dunefields in northern China during the Holocene showed that Asian monsoon and resultant effective moisture have played an important role in the evolution of dunefields at the millennial time scale. Further analysis indicated that the dune evolution in the Horqin dunefield before 3 ka was synchronous with climatic changes. However, increasing human activity has impacted dune evolution during the last 3 ka.

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The pattern of Holocene palaeoclimatic change in arid-semiarid northern China is debated. The terminal Huangqihai Lake is located at the northern margin of the modern East Asian summer monsoon and sensitive to climate change. We present here a sedimentary section from Huangqihai lake basin which comprises lacustrine and fluvial deposits and is about 8–9 m above the present lake level. Quartz optically stimulated luminescence (OSL) dating was employed to construct the chronology of the section. Based on the OSL chronology and the sedimentological and granulometric analysis, we conclude that (1) the Huangqihai Lake experienced a humid climate during the early part of the Holocene (from c. 10.2 ± 1.0 to 6.7 ± 0.7 ka) with a persistent and stable high lake level; (2) the lake level began to decline indicating aridification between 8.7 ± 0.8 ka and 6.7 ± 0.7 ka, and the climate was drier and variable after 6.7 ± 0.7 ka compared with that of before; (3) from 2.2 ± 0.2 to 0.93 ± 0.07 ka the climatic conditions were highly variable and continuously deteriorating, and the lake was turned into a playa for most of the time. In summary, the climate showed a general drying trend from the early Holocene to the late Holocene.