第六届青年地学论坛

1704 / 2019-08-27 14:35:19

Vegetation and climate changes since the Last Glacial Maximum reflected by a peat record in Dawa Mountain of Sichuan Province

14、古生物、古地理与古环境 > 专题6：亚洲不同时间尺度古环境研究的孢粉学视角

Yunkai Deng1, Chunmei Ma 1,2*)
1) School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023
2) Jiangsu Collaborative Innovation Center for Climate Change, Nanjing 210023Climate changes since the Last Glacial Maximum(LGM), it has been an important period of global change research in the past. During this period, global climate experienced drastic changes from glacial to interglacial. Palynology research helps us understand the relationship between vegetation and climate changes from the LGM. The high-resolution palynological analysis of the peat deposits in Dawa Mountains in Sichuan Province has supplement the lack of palynological data in the in the upper reaches of the Yangtze river in China, and reconstructed the vegetation and climate changes in this area since the LGM. During the LGM, the trees and shrubs vegetation in this region was dominated by Betula, Rosaceae and Quercus(Heterobalanus), while the upland herbs were dominated by Aretmisia, and the wetland herbs were dominated by Myriophyllum. At the same time, the content of Pediastrum was high indicate the shallow lacustrine environment, and during this period the climate was cold and wet. After entering the Last Deglacial period, the content of Betula, Rosaceae and Quercus(Heterobalanus) decreased significantly, and the content of Pine increased. At this stage, the upland herbs herbs were mainly Ranunculaceae and Poaceae, and the content of Artemisia was decreased. Cyperaceae content increased significantly and became the main wetland herbs, and the content of Myriophyllum was at low value, while the content of Pediastrum also decreased gradually, and they both basically disappeared in the end of the Last Deglacial. Compared with the LGM, the climate changed to warmer and drier. In the Holocene, plant species were richer than the LGM, and the vegetation types were mainly Quercus(E), Castanopsis/Lithocarpus, Cyclobalanopsis and Rosaceae.The content of Cyperaceae decreased gradually after entering the Holocene.Based on the results of the pollen analysis of the core, the study concluded that the LGM was wetter than the Last Deglacial and Holocene, the LGM was cooler and wetter, the Last Deglacial was climate changed to warmer and drier, and the Holocene was warmer and drier.In the modern times, the fern and upland herb Ranunculaceae and Artemisia were significantly increased, which may be affected by human activities.

Keywords: LGM, Dawa Mountain peat,Pollen analysis,Vegetation succession,Climate change