基于介形类群落和壳体地球化学重建的循化盆地晚渐新世-中新世古水文变迁历史

青藏高原东北缘新生代气候-构造耦合历史是研究青藏高原新生代时空演化过程和气候环境效应的重要窗口。而目前关于气候和构造这两大因素在青藏高原东北缘晚新生代盆-山耦合过程中扮演的角色依然存在争议，造成这种争议的关键原因是基于传统碎屑岩载体的气候代用指标指示意义不明确。介形类对其宿生水体的温度、盐度和水化学组成等诸多水文信息十分敏感，是重建汇水盆地深时古水文变迁历史的重要载体。循化盆地处于青藏高原东北缘盆地群的中心位置，其新生代古水文变迁历史是联系青藏高原东北缘气候-构造耦合历史的重要纽带。基于此，本研究选取有精确磁性地层年龄约束的循化盆地晚渐新世-中新世湖泊-三角洲相地层为研究对象，基于介形类载体群落古生态分析和壳体多手段地球化学分析，建立循化古湖地质历史时期古水文学信息档案，在此基础上重建循化盆地晚新生代古水文变迁历史，进而为青藏高原东北缘新生代气候-构造耦合历史研究提供新的科学依据。

The Cenozoic coupling history of climate-tectonics in the NE Tibetan Plateau provides a new window into the process of space-time evolution in the Tibetan Plateau and its climatic and environmental effects. To date, the role of the two major factors of climate and tectonics in the process of basin-mountain coupling on the NE Tibetan Plateau during the late Cenozoic is still controversial. The key reason for this controversy is that the specific indication of those climate proxies based on traditional clastic rock carriers is not clear. Ostracods are sensitive to hydrological factors such as temperature, salinity and lake hydrochemistry and can therefore have implications for deep-time paleohydrological reconstructions. The Xunhua Basin is located in the center of the basin groups in the NE Tibetan Plateau, and thus its paleohydrological history is a key link connecting the coupling history of climate-tectonics in the NE Tibetan Plateau. In this study, we focus on the well-dated late Oligocene-Miocene deltaic-lacustrine stratum from the Xunhua Basin. Faunal assemblages and ostracod shell geochemistry will be applied to establish paleohydrological dataset for Paleo-Xunhua Lake. On this basis, the history of late Cenozoic paleohydrological changes in the Xunhua Basin can be reconstructed, which in turn provided important scientific basis for the coupling history of climate-tectonics in the NE Tibetan Plateau.