摘要
以揭示碳酸盐岩和硫酸盐岩相伴沉积时发生的复合岩溶形成机制为目的 ,采用室内模拟实验方法 ,利用反应路径模型研究了水流路径上碳酸盐岩→硫酸盐岩 (简称层序 1)和硫酸盐岩→碳酸盐岩 (简称层序 2 )两种层序时发生的地球化学作用 ,根据质量平衡原理 ,计算了水岩间发生的地球化学作用强度 ;探讨了硫酸盐岩成因、岩溶发育的环境温度对复合岩溶的影响。结果表明 ,复合岩溶形成机理与可溶岩层序关系密切 ,层序 1中 ,发生两种可溶岩的溶解作用 ;层序 2中 ,除硫酸盐岩 (石膏和半水石膏 )溶解外 ,碳酸盐岩 (白云岩 )发生的是去白云化作用。这些作用间通过不同的机制相互促进 ,导致复合岩溶较单一可溶岩的岩溶更发育。复合岩溶的发育程度还受溶液 pH值和环境温度影响 ,溶液pH值降低、环境温度升高都利于复合岩溶发育。
In order to understand the mechanism related to the formation of compound karstification in the coexistent system of carbonate rocks and sulphate rocks, the experimental work on the dissolution processes of soluble rocks was carried out in laboratory. Two different sequences along flow path, i.e. sulphate rock to carbonate rock and carbonate rock to sulphate rock, were simulated by the experiment, respectively. Based on the theory of mass balance and the model of flow path, the mass transfer in water rock interactions is calculated. Then, the effects of the geneses of sulphate rocks and environmental temperature on compound karstification are discussed. The results show that the compound karstification has a close relation with the rock sequences. In the sequence of carbonate rock to sulphate rock, both rocks are dissolved. However, in the sequence of sulphate rock to carbonate rock, sulphate rocks (gypsum and bassanite) are also dissolved but the carbonate rock (dolomite) are dedolomitization. The different mechanisms of these geochemical processes accelerate the development of compound karstification compared with the karstification developed in single soluble rocks. The pH value of solution and temperature of ambient environment play an important role in the development of compound karstification. Decreasing pH value and increasing temperature are suitable for the developing of compound karstification.
出处
《地学前缘》
EI
CAS
CSCD
2003年第2期495-500,共6页
Earth Science Frontiers
基金
国家自然科学基金资助项目"硫酸盐岩溶发育机理与环境演化效应研究"( 4 9872 0 95 )
