3Ma以来西部黄土高原古降水变化及其对黄河演化的启示

晚新生代东亚夏季风变化历史及周期特征对理解黄河形成演化具有重要意义。然而，由于西部黄土高原缺乏可靠的长序列季风降水记录，黄河形成演化与区域气候变化的关系及中、西部黄土记录的周期特征仍存在不同观点。兰州盆地处在季风边缘区，发育了一系列的黄河阶地和第四纪巨厚黄土沉积，是开展黄河形成演化和第四纪气候变化综合研究的关键区域。本项目提出对西部黄土高原兰州地区新发现的3百万年以来的红粘土-黄土钻孔样品进行系统的低温和常温环境磁学分析，首次重建3百万年以来西部黄土高原古降水变化历史，厘清西部黄土高原降水变化规律和周期特征，澄清黄河发育演化与区域气候变化的关系，为河流演化模型和第四纪黄土高原季风降水空间对比提供重要的基础数据。

The history and periodic characteristics of the late Cenozoic East Asian summer monsoon are of great significance for understanding the formation and evolution of the Yellow River. However, there still have different opinions on the relationship between the formation and evolution of the Yellow River and regional climate change, as well as the periodic characteristics of loess records in the central and western Chinese Loess Plateau, due to the lack of reliable long-term monsoon precipitation records in the western Chinese Loess Plateau. The Lanzhou Basin is located at the edge of monsoon area, have a series of Yellow River terraces and Quaternary thick loess deposits. It is the key area for the comprehensive study of the formation and evolution of the Yellow River and Quaternary climate change. This project proposes a systematic low and normal temperature environmental magnetic analysis of the newly discovered red clay-loess drill core in the Lanzhou Basin since 3 Ma, to reconstruct the history of summer monsoon precipitation in the Lanzhou region since 3 Ma, to find out the law and periodic characteristics of the precipitation in the western Chinese Loess Plateau, to clarify the relationship between the evolution of the Yellow River and regional climate change, and provides important basic data for the river evolution model and the spatial comparison of monsoon precipitation in the Chinese Loess Plateau during the Quaternary.