中文摘要：

南京葫芦洞石笋末次冰期气候记录闻名于世，但至今葫芦洞未见全新世石笋，且缺失现代碳酸盐沉积，这个问题多次被同行提起。通过与同一气候条件下现代沉积作用旺盛的安徽蓬莱仙洞进行了近一个水文年的水文地球化学对比研究，从监测数据分析获知，两洞穴滴水中阳离子浓度以及其他许多地球化学指标的差异并不大，但葫芦洞滴水的SO42-和Cl-含量均比蓬莱仙洞的高一个数量级。室内模拟实验也表明，滴水中加入SO2-和Cr将使碳酸钙溶解度显著增加。综合这些结果，提出“盐效应”很可能就是南京葫芦洞缺失现代碳酸盐沉积的一个重要原因，并由此进一步分析了葫芦洞缺失全新世石笋的可能机理。目前中国许多洞穴由于缺乏现代沉积致使沉积景观逐渐老化，本文报道的分析方法对认识其中的原因机理具有一定意义，但其结论仍需接受更加严谨的观测和实验的验证。

英文摘要：

To better understand the growth mechanism of the stalagmite, cave monitoring should be performed. Nanjing Hulu Cave（32°03′, 119°02′E） is well known for its last glacial climate record from the stalagmites. But no Holocene stalagmites and no modern secondary carbonate deposit were found in this cave,why？ For answering this question,the authors made monthly in-situ monitoring of hydrogeochemistry at Hulu Cave and another comparative cave, Penglaixian Cave （30°14′N, 117°32′E） in Anhui Province which locates under the same climate conditions with Hulu Cave and possesses a large number of modern secondary carbonate deposits. To detect the possible causes of loss of active speleothem in Hulu Cave and the different conditions controlling the modern secondary carbonate deposition in the two caves, seven drip sites（three in Hulu Cave and four in Penglaixian）were selected, and each of them has a stalagmite at the bottom. Two bottles of drip water were collected at each drip site,one of which was used for testing the anions content of drip water on ion chromatograph（ICS-3000） and the other for cations content testing on ICP-OES （Inductively Coupled Plasma Optical Emission Spectrometry, Prodigy）. Some other indexes （for example, cave CO/ concentration, cave air temperature, relative humidity, the drip rate, temperature, pH and EC of drip water, and so on） were also monitored in both caves once a month. The testing and monitoring results show that, except the contents of anions are dramatically different, the other indexes in two caves are similar. The content of SOl- and Cl- are nearly ten times higher in Hulu Cave drip water （ SO/a- is about 22.74mg/L and Cl is about 7.11 mg/L on average）than those in Penglai Cave drip water（ SO4 2- is about 3.58mg/L and Cl- is about 0.85mg/L on average）. With a lab experiment,we discover that the existence of SO24- and Cl- of cave drip water will increase calcite solubility significantly, which is konwn as salting-in effect. Furthermore, by com