喷气沉积矿床成因研究的几个问题

A STUDY OF SOME PROBLEMS ABOUT THE ORIGIN OF EXHALATIVE-SEDIMENTARY ORES

大的喷气沉积型矿床可能由穿过盆地沉积柱进入基底岩系的热水对流房排放到海底形成。热液对流模式已经取得多方面地质地球化学证据及流体动力学的定量检验。喷气成矿作用是在很长地质历史时期中广泛发育的一种重要成矿作用。大陆边缘断裂槽中的深囟水盆及相邻的碳酸盐台地上的沉陷洼地都是有利的成矿环境。

Exhalative-sedimentary ores are of the syngenetichydro thermal origin. The underlying stockword zone of the stratiform orebody and the exhalites in ore-bearing zone are the main features of these deposits.The concordant single lens or the vertical array of ore lenses in a definite strata horizon, the massive banded and laminated ore structures and the metal zoning in vertical direction through the ore-bearing sequences are also of the characteristics showing the syngenetic-hydrothermal origin. The hydrothermal-convection model may successfully explain the conditions and processes of the formation of these ore deposits, and the size of the deposits is tested by using a thermal balance model. Exhalative activity happened frequently in a long geological history. The formation of the exhalation sedimentary deposits is related to several definite tectonic setting. The largest exhalation sedimentary deposits are found to be located in the fine clastic sedimentary rocks of trough facies. And the adjacent depression on the carbonate platform is another type of favourable environment for the formation of these deoosits.