发生在末次冰期的周期性极端冷事件——Heinrich事件，是晚近地质时期最重要的气候突变事件之一，对北半球气候系统和陆地生态格局产生了深刻影响。然而迄今为止，Heinrich事件在东亚地区的环境效应仍不清楚，尤其在我国北方生态环境脆弱区。本项目选择我国干旱-半干旱过渡区河套平原湖相HJ01孔为研究对象，利用AMS14C、光释光和铀系定年技术构建沉积岩芯年代模型，基于孢粉分析定量重建河套平原末次冰期高分辨率植被演替序列。在此基础上，辨识河套平原记录的Heinrich事件，分析Heinrich事件期间和前后区域植被组成的变化过程，估算植被组成对气候突然转冷的响应特征（植被变率、变幅和阈值）。本项目将为我国干旱-半干旱过渡区提供较长时间尺度高分辨率古气候记录，揭示气候突变事件期间生态环境脆弱区植被的响应特征和演替过程，为应对未来极端气候事件提供重要启示。

The Heinrich event, which was the periodic extreme cold event that occurred during the last glacial period, was one of the most important abrupt climate events in recent geological periods. The Heinrich event has profoundly affected climate system and terrestrial ecological pattern of the northern hemisphere. However, the environmental effects of the Heinrich events in East Asia are remained unclear, especially in the fragile ecological area in northern China. In this project, the lacustrine HJ01 drilling core was selected as research target for high-resolution palaeovegetaion study from the Hetao Plain in the arid and semi-arid transition zone. The AMS14C, Optically Stimulated Luminescence and U-series disequilibrium dating techniques were used to construct a chronological model of the HJ01 core. Based on pollen analysis, a high-resolution vegetation succession sequence during the last glacial period in the Hetao Plain was quantitatively reconstructed. Then the Heinrich events ware identified, and the changes of vegetation composition during and before the Heinrich events were analyzed, and the response characteristics (vegetation variability, amplitude, and threshold) of the vegetation composition to suddenly cooling of the climate were estimated. This project will provide a long-scale and high-resolution paleovegetation record for arid and semi-arid transition zone in China, reveals the response characteristics and succession process of abrupt climate events on vegetation in ecologically fragile areas, and provides important inspiration for coping with future extreme climate events.