石笋氧同位素记录表明末次冰期东亚季风环流存在一系列千年尺度的显著变化。但是，由于氧同位素的变化主要反映水汽从源区向沉降地区传输过程中水汽剩余比的差异，因而不能用来指示区域降雨的变化。项目申请人前期研究发现，湖北豪猪洞石笋中的微量元素指标（如Sr/Ca，Mg/Ca，Ba/Ca等）具有很好的记录区域古水文变化的潜力，通过石笋微量元素记录和古气候模拟的结合，重建了长江中游末次冰消期的古水文过程。本项目首先通过洞穴现代过程研究，明确豪猪洞石笋微量元素指标与区域降雨之间的响应机制。然后对两个生长时段相同，且具有年层特征的石笋样品进行高分辨率的碳氧同位素和微量元素研究，同时借助古气候模拟，探究末次冰期H4事件演化过程中长江中游古水文变化特征，为揭示末次冰期千年尺度气候突变和东亚古水文之间的联系提供依据。

Speleothem oxygen isotope records from China have revealed that East Asian monsoon underwent a series of millennial-scale climate variability during last glacial, such as ‘Heinrich Events’. However, the change of oxygen isotope is mainly reflected upstream rainout integrated between different moisture sources en route to the cave sites, but not local rainfall. Our previous study indicated that trace element ratios from the stalagmite in the Haozhu Cave, such as the Sr/Ca, Mg/Ca, Ba/Ca, could be used to reflect local hydrological changes. Through the combination of speleothem trace element records and climate model simulations, we reconstructed the hydroclimate changes during last deglaciation in the middle Yangtze River. In this study, we will first conduct a series of cave monitoring work in the Haozhu Cave to confirm the mechanism between speleothem trace element changes and regional precipitation. After that, we will conduct high resolution carbon/oxygen isotope and trace elements research upon two contemporary and layer-characterised stalagmite samples during Heinrich Event 4 (HE4). Besides, we will use the coupled speleothem trace element and climate model to reveal the hydroclimate changes during HE4 and the linkage between millennial-scale abrupt climate changes and East Adian hydrological response.