浑善达克沙地湖相沉积记录的全新世植被和气候变化研究

季风边缘区全新世千年和百年尺度气候变化时空变化规律的揭示，对于理解东亚夏季风、冬季风和西风带气候系统演化历史及其与热带海洋（ENSO）、北极（AO）以及北大西洋（NAO）的作用过程和联系机制具有重要意义。然而，已有序列在年代控制、分辨率和地理分布等方面存在不足，阻碍了学界对上述问题的深入认识，亟待在该区域建立高质量的全新世植被和气候变化序列。为此，本项目以浑善达克沙地湖泊沉积物岩芯为研究对象，以陆源植物残体或全样有机质AMS14C年代和210Pb-137Cs交叉定年为框架，结合现代花粉-植被-气候关系研究，利用孢粉、粒度、磁化率、元素地球化学等代用指标高分辨率地定量重建浑善达克沙地全新世植被及气候环境变化序列，集成研究揭示季风边缘区全新世千年及百年尺度的植被和气候变化的时空分布规律，为认识全新世东亚夏季风演化和热带海洋、高纬度以及北大西洋的作用过程和联系机制提供帮助。

The temporal and spatial patterns of the Holocene climate change of the marginal monsoon area on millennial and centennial scales, is of great significance to understand the evolution of the climate subsystems including the East Asia Summer Monsoon (EASM), the Asia Winter Monsoon (AWM) and the Westerly, and the coupling dynamics and the linkage between the tropic ocean, the arctic and the North Atlantic. Nevertheless, consensuses were still not reached possibly because that those published Holocene climate sequences in the marginal monsoon area were somewhat deficient on the age control, the sampling resolution and the geographic coherency. Therefore, this proposal aims at the high quality reconstructions of the Holocene vegetation and climate sequences of Otindag dune field of Inner Mongolia, the nature of the millennial and centennial scale climate change and the coupling dynamics and linkage between the tropic ocean, the arctic area and the North Atlantic area. Specifically, two lacustrine sediment sequences were retrieved in the center of two lakes using the UWITEC piston corer and age model were constructed on the base of the AMS 14C dating of the terrestrial plant residues and/or the organic matter. In case that no terrestrial plant residues could not be found, scientific appraises for potential carbon reservoir effect were made using the comparison with the 210Pb-137Cs dating for the top layer, the dates of occasional terrestrial plant residues, and the references of the dating of the water and/or the hydrophyte. On the base of the age-depth model, vegetation and climate sequence were reconstructed using the pollen, grain size, susceptibly and the geochemical proxies. Based on these two Holocene sequences and those published Holocene sequences, synthesis were conducted to explore the millennial and centennial scale climate pattern, and comparisons were made to disclose the coupling dynamics and linkage mechanisms with the tropic ocean, the Arctic area and the North Atlantic area. Furthermore, the vegetation responses to the climate changes during the Holocene were studied to provide analogs or references for the regulations of modern ecology.