摘要
结合水化学的野外观测及室内计算,作者对桂林岩溶试验场、四川黄龙风景区和贵州乌江渡坝区3个岩溶动力系统的碳稳定同位素特征进行了分析,进而对系统的性质、系统中CO_2的来源、碳酸盐沉积过程中的碳同位素动力分馏、水化学和钙华的成因及热水钙华的^(14)C测年等地球化学问题作了探讨。结果表明,桂林岩溶试验场属于表层岩溶作用动力系统,其中的侵蚀动力主要来源于大气降水溶解土壤中的CO_2;四川黄龙风景区属于深部岩溶动力系统,侵蚀动力来自大气降水溶解幔源的CO_2;贵州乌江渡坝区岩溶系统,虽然属于表层岩溶动力系统,但其中一部分的同位素和水化学特征已受到人类活动的重大影响。
On the basis of the stable carbon isotope geochemical and hydrochemical studies and experiments the paper summarises the features of stable carbon isotope geochemistry in the karst systems of the Guilin Karst Experimental Site, Huanglong Ravine and Wujiangdu Dam Site. Furthermore , an attempt is made to solve several geochemical problems, such as the origin of CO2 in the systems, kinetic fractionation of carbon isotopes in the process of carbonate deposition, hy-drochemistry and formation of tufa,and carbon-14 dating of tufa of hydrothermal origin. The results show that three kinds of karst dynamic system can be distinguished: (1) the shallow system , such as the Guilin Karst Experimental Site, in which soil CO2 provides the aggressive agent for karst processes; (2) the geothermal system, such as the Huanglong Ravine, in which meta-morphic or/and juvenile CO2 is the source of aggressivity for karst; (3) the anthropogenic system, such as the Wujiangdu Dam Site, in which the stable carbon isotope geochemical and hydrochemical features have been greatly affected by anthropogenic activity.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1997年第3期281-288,共8页
Acta Geologica Sinica
基金
国际地质对比计划IGCP 379项目
国家自然科学基金项目(编号49632100)
地质矿产部"九五"重点科技项目
关键词
岩溶
动力系数
炭
稳定同位素
地球化学
karst dynamic system
stable carbon isotope
geochemistry
hydrochemistry
tufa formation
carbon source
