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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SO_4~(2-)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SO_4~(2-)和Cl~-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。
Nanjing Gourd Cave stalagmite climatic record last glacial climate known, but so far no gourd hole Holocene stalagmite, and the lack of modern carbonate deposition, this issue has repeatedly been raised by peers. Hydrobiochronological comparisons of nearly one hydrological year were carried out with the Penglai Cave at Penglai County, Anhui Province, which is rich in modern sedimentation under the same climatic conditions. According to the monitoring data analysis, the cation concentration in the two caves drip water and many other geochemical indicators are not significantly different , But the contents of SO_4 ~ (2-) and Cl ~ - in the dripping water of Huludao Cave were both an order of magnitude higher than that of Penglai Cave. Laboratory simulation also showed that the addition of SO_4 ~ (2-) and Cl ~ - in the drip water will increase the solubility of calcium carbonate significantly. Summarizing these results, it is proposed that the “salt effect” is likely to be an important reason for the loss of modern carbonate deposits in Nanjing Hulu Cave, and the possible mechanism for the loss of Holocene stalagmites in Huluhudong is analyzed. At present, many caves in China are aging due to the lack of modern deposition. The analysis methods reported in this paper are of great significance for understanding the causes and mechanisms of the sedimentary environment. However, the conclusions still need to be verified by more rigorous observations and experiments.