对北半球中高纬度贯穿整个第四纪的连续高分辨率钻孔的研究，可以揭示全球古环境变化的重要气候信息、发现新的重大科学问题。但是，我国目前对长尺度、连续的、高分辨率记录的研究还有待加强，特别是在干旱半干旱的过渡地区。中国西北部银川盆地720米PL02钻孔提供了干旱半干旱地区过渡地带3.4 Ma以来的连续沉积记录，其蒿藜比序列与LR04深海序列高度吻合。本项目拟在已有古地磁年代学基础上，采用宇宙成因核素埋藏测年、光释光测年和碳十四测年方法完善PL02孔的年代学框架。并建立分辨率约2ka的孢粉记录，获得干旱半干旱区银川盆地3.4 Ma以来的孢粉古植被信息，结合现代表土花粉对3.4 Ma以来的气候变化进行定量重建，以期揭示该地区第四纪以来的环境演化过程，摸清气候变化的规律，探讨古气候变化的轨道周期特征及其驱动机制。

Integrated studies of continuous and high-resolution drilling cores throughout the Quaternary in middle and high latitudes of the Northern Hemisphere, could reveal important information of global paleo-climate environmental changes, discover new significant scientific issues. However, these studies in China have been hindered by the lack of long-term, continuous, high-resolution records, especially in the transition zone of arid and semi-arid zone. A sediment core of the 720m PL02 borehole from the Yinchuan Basin in the northwest China provides a 3.4 Ma pollen record in the transition zone of arid and semi-arid zone. The preliminary ratio of Artemisia and Chenopodiaceaeresults is well corresponded with global benthic δO18 records stack LR04. This project is planned to use the methods of cosmogenic nuclide burial dating, OSL dating and AMS 14C dating to improve chronological framework, on the basis of existing magnetostratigraphy dating. Moreover, it is also obtain a pollen record, which resolution is approximate 2ka. The pollen record reflect paleo- vegetation changes in Yinchuan Basin during Quaternary. Combined with the modern surface pollen samples, to do quantitative reconstruction of climatic changes since 3.4 Ma. Then, the results could reveal environmental evolution process in Yinchuan Basin, find out the law of climatic changes, and explore the orbital periods of paleo-climatic and the drive mechanism.