Late Holocene dune mobilization in the Horqin dunefield of northern China

摘要

The late Holocene environmental change and its relationship with climate and human activities in the Horqin dunefield of northern China are poorly understood. In the current study, we presented a new reconstruction of late Holocene dune mobilization in the Horqin dunefield based on 68 quartz OSL ages from 25 dune sections and interpretations of historical documents. These sections were selected from a variety of different geomorphological units across the studied region. The results show that at least four phases of dune mobilization were distinguished during the last 2000 years in Horqin dunefield, corresponding to similar to 400-700 CE, similar to 1200 CE, similar to 1800 CE and after 1900 CE, respectively. By comparison with other well-dated paleoclimate records and analysis on human activity records, we infer that the cold-arid climate caused the dune mobilization around 400-700 CE; dune mobilization around 1200 CE can be attributed to the combinative impacts of cold climate and extensive human activities; increasing human activities play a dominate role in the latest two phases of dune mobilization at around 1800 CE and after 1900 CE, even though the climate warming and drying in 20th century may also contribute to the last phase of dune mobilization. (C) 2017 Elsevier Ltd. All rights reserved.