中文摘要：

采用Avaatech型岩芯X射线荧光光谱扫描仪技术,对发育有连续3900年纹层（18.3～14.4ka B.P.时段）的南京葫芦洞YT石笋进行了Sr,Ba和Pb微量元素分析.选择Sr/Ca,Ba/Ca和Pb/Ca作为代用指标,研究了末次冰消期洞穴地点岩溶水文条件和气候变化特征.Ba/Ca和Pb/Ca值从大约17.5ka B.P.开始呈现出减小的趋势变化,而Sr/Ca呈现出在大约16.1ka B.P.发生转折的“V”型演化趋势.Sr/Ca反映了岩溶水在上覆围岩中的滞留时间（与夏季降水相关）,而Ba/Ca和Pb/Ca指示了土壤及其基岩的本底值和淋滤作用强度.Sr/Ca比值与纹层厚度、δ^13C记录在数百年-千年尺度上呈现一致的变化,共同指示了南京葫芦洞地点有效湿度的变化过程,与δ^18O的对应性表明葫芦洞石笋δ^18O可以指示当地季风降雨量的变化过程.此外,石笋Ba/Ca和Pb/Ca与格陵兰粉尘和Ca^2＋记录在长期趋势上呈现一致变化,表明该类元素比值主要反映与冬季风强度密切相关的粉尘活动强度变化.研究结果表明,东亚冬、夏季风对神秘期内发生的冰漂碎屑事件（H1a,16.1ka B.P.和H1b,17.5ka B.P.）具有不同的响应方式.Ba/Ca和Pb/Ca序列的功率谱分别呈现出66a、35a、23a、14a和61a、46a、22a、19a、17a、15a周期,说明北大西洋涛动和太阳活动影响着冬季风强度的高频变化.

英文摘要：

The Hulu Cave （32°30′N,119° 10′E） is located ～ 28km east of Nanjing,Jiangsu Province,East China.The cave is approximately 64m long,and overlaid on the Lower Ordovician Series limestone bedrock with a ca.30cm soil cover.The current mean temperature in the cave is 15.4℃ and the cave relative humidity is close to 100%.The mean annual precipitation at the cave site is 1015mm,80% of which falls during the summer,from June through September.Stalagmite YT was collected in the deep cave.The sample is 220mm in length,with a diameter from 60mm to 90mm.It is composed of typical coalescent columnar-fabric calcite crystals,and shown well-developed μm-scale laminations.We identified a light-yellow band at the depth of 173mm,indicating growth hiatus,which is also supported by 230Th dating result.Therefore,we only focus our trace element analysis on the upper portion （0 to 173mm from the top）.The trace metals of Sr,Ba and Pb in stalagmite YT were analyzed with Avaatech XRF Core Scanner,equipped with a variable optical system that enables any resolution between 10mm and 0.1mm at the Surficial Geochemical Laboratory,Nanjing University,China.A ca.4.3-year-resolution trace elements ratios records from stalagmite YT between 18.3ka B.P.and 14.4ka B.P.was constrained by four 230Th dates and 3900 annual bands.The proxies of Sr/Ca,Ba/Ca and Pb/Ca ratios were selected to study the site-specific karst hydrological conditions and the characteristics of the climate change during the last deglaciation.The Sr/Ca proxy show a long-term trend of ＂V＂ type,with the turning points occur at approximate 16.lka B.P.,whereas the other two elements ratios show a gradual decreasing trend since 17.5ka B.P.The Sr/Ca reflects the residence time of drip waters in the host limestone above the cave and therefore is associated with the summer precipitation.On the other hand,the variations in Ba/Ca and Pb/Ca are interpreted to indicate the strength of leaching effect.At millennial timescales,the variations of Sr/Ca,annual layer thickness a