东亚季风气候在轨道尺度上究竟是受控于低纬太阳辐射量的岁差驱动还是高纬过程的冰盖驱动，是第四纪领域的重要科学问题。目前以中国北方的黄土-古土壤序列和南方的洞穴石笋沉积为主要代表的古气候变化记录所反映的东亚季风的变率及其驱动机制存在着差异。在对季风变化非常敏感的边缘区寻找独立的长尺度记录，将有助于厘清轨道尺度上季风演化的机制问题。本项目拟在季风边缘区的连续湖泊沉积岩芯记录中，通过高精度的释光年代学（辅以其它测年手段）研究，重建晚更新世“大湖期”发生的时间序列；探明过去两个冰期-间冰期旋回以来的干旱-半干旱区湖泊演化模式；结合地层学和沉积学分析，从有明确环境指示意义的代用指标中，提取出在轨道尺度上东亚夏季风（与湖泊水文状况相关）和冬季风（与湖泊风沙输入相关）变化历史的信息。有望从湖泊沉积记录的角度，为研究第四纪东亚季风变化的动力学机制补充新的证据。

The East Asian summer monsoon (EASM) is a key component of circulation systems across low-to-middle latitudes; it plays a crucial role in interhemispheric heat and moisture transport, and serves as main rainfall supply for the densely populated East Asia. Over the past decades, our knowledge on the monsoons’ evolution on different timescales and underlying dynamics has significantly increased based on proxy analysis of a variety of geological records and numerical modelling data. However, the responsible forcing mechanisms governing EASM variabilities on orbital timescales are still competing, especially in the relative importance of external drivers (e.g., solar insolation) and internal factors (e.g., ice volume). There have been two major interpretations for the response of existing EASM paleoclimate records to the forcing factors mainly associated with solar insolation and global ice volume. The summer monsoon proxy (magnetic susceptibility) of loess-paleosol sequences over the Chinese Loess Plateau (CLP) are characterized by distinct glacial-interglacial variations with a dominant 100-ka cycle during the last 800 ka, implying a strong connection to change in ice-sheet volume as a modulation factor of the thermodynamic contrast between the Asian continent and the Pacific Ocean. To the southern China (SC), in contrast, a large body of speleothem oxygen isotope records as an indication of EASM intensity and rainfall variability revealed a dominance of precession cycles of ~23 ka, suggesting a direct link of monsoon to insolation forcing. Overall, our understanding of EASM variability on orbital time-scales and corresponding causes remains incomplete. In this project, we proposed a long lacustrine sediment sequence retrieved from a closed lake (Zhuyeze) located the Asian monsoon marginal area, which is independent to both loess-paleosol sequences from CLP north China and speleothem records from SC. Combined with multiple dating approaches (14C, magnetostratigraphic dating, and ESR), luminescence techniques (with high resolution sample strategy) will be mainly applied to build up the chronological framework of the sediment core; various proxies with clear environmental implications will be used reconstruct late Quaternary lake evolution, and the variability of East Asian summer and winter monsoons over the glacial-interglacial time scales will also be reconstructed based on the changes hydrological and dust input in the lake. Compared with the sporadically preserved geomorphological evidences (e.g. shorelines, beaches and terraces), the deep core sediments are potential to provide quasi-continuously high resolution lake evolution and EASM change records over the last two glacial/interglacial cycles.