广东长埔锡矿床的成矿特征及物质来源

长埔锡矿床受地层层位控制,构造定位,并经历了两次矿化,与晚侏罗世火山作用没有直接的成因联系,而与莲花山断裂动力热变质作用密切相关.下侏罗统金鸡群是一富含锡建造,除含有吸附状态的锡外,还含有古砂锡石及含锡的同生沉积物,并且矿区外围存在一个明显的锡丰度降低场,因此金鸡群是重要的矿源层.铅、硫同位素组成及稀土元素地球化学特征也说明成矿物质主要来自地层.成矿水介质以变质水为主,并有大气降水参与.

METALLOGENTIC CHARACTERISTICS AND SUBSTANCE SOURCE OF CHANGPU TIN DEPOSIT, GUANGDONG

The Changpu tin deposit was controlled by stratigraphy level and structure, undergone two epoches of mineralization, had not direct genetical relation to the late Jurassic volcanism, but was close related to the dynamic metamorphism of Lianhuashan fault belt. The Jinji Group of lower Jurassic series is a suit of formation rich in tin. In addition to the tin in adsorption state, the strata contain tin-bearing syngenetic sediments and ancient elastic cassiterit. Further, there is obviously a depletion of tin in the periphery of the mining area. Therefore, the Jinji Group is an important source bed. Lead, sulfur isotope composition and the characteristics of REE geochemistry indicate that metallogentic substance mainly came from the group. Ore-forming fluid chiefly was metamorphic water but mixed by meteoric water. The tin deposit belongs to sedimento-metamorphic stratobound ore deposits.