摘要
成岩成矿关系问题,特别是成矿作用与岩浆活动的专属性问题,一直是矿床学研究中的重要课题。粤东地区热液脉状锡、钨(多金属)矿床产于中生代花岗质火山岩、次火山岩和侵入岩组成的火山侵入杂岩带中,成岩年龄与成矿年龄一致,但矿床地质、矿床矿物流体包裹体和同位素地球化学没有相对标准来区分这些来源于岩浆作用不同阶段、不同产出状态岩浆岩的成矿物质特征,使得人们对于区内矿床成因的认识不一。文中运用稀土元素地球化学方法,着重探讨和对比了矿床矿石、蚀变岩石及与成矿有关的岩浆岩的稀土元素特征和配分型式,并进一步根据在不同压力条件下Cl-在熔体和热液间的分配系数实验数据和不同压力条件下热液与相应熔体平衡时的稀土元素分配系数实验结果,分别计算了厚婆坳锡矿床和莲花山钨矿床与矿区有关岩浆岩熔体平衡的热液中的稀土元素浓度并制出配分型式,再与矿床矿石及矿石矿物稀土元素配分型式比较,从而确定成矿与侵入阶段的花岗岩岩浆活动关系密切。区内矿床为岩浆热液矿床。研究结果表明,稀土元素作为热液流体来源的示踪剂能有效地确定火山侵入杂岩带的成岩成矿专属性。
The problems of the relations between petrogenetic and minerogenetic, especially, magmatic and minerogenetic specializations are very important in the studies of mineral deposit.In eastern Guangdong Province, the tin and tungsten (polymetallic) vein deposits distribute in the Mesozoic volcanic intrusive complexes zone which consists of granitic volcanic rocks, subvolcanic rocks and intrusive rocks. The isochron ages of the granitic complexes and the tin and tungsten deposits are almost identical. But there are no relative standards for distinguishing the characteristics of the ore forming materials that come from the magmatic rocks of different occurrences and different stages of the magmatic activities. So there are different views for the genetic type of the tin and tungsten deposits.In this paper rare earth elements have been used as hydrothermal tracer during the formation of hydrothermal mineral deposits in volcanic intrusive complexes zone. According to the contrasts of the REE composition and Europium anomaly characteristics of ores, altered rocks and related magmatic rocks of Houpo'ao tin deposit and Lianhuashan tungsten deposit,it seems that the mineralization is related to intrusive magmatic activities. Further, according to the experiments of the Cl - concentrations in the hydrothermal fluids in equilibrium with the original melt and the distribution coefficients of REE in corresponding magmatic rocks, the contents of REE in each hydrothermal fluid which equilibrates with the magmatic rocks of different occurrences have calculated. The discussions of the chondrite normalized REE patterns and Europium anomaly characteristics of ores, minerals of ores and hydrothermal fluids in equilibrium with the related magmatic rocks in the mine show that the tin and tungsten deposits mineralization system is controlled by intrusive magmatic activities. This paper has given an example that REE can be used to determine the magmatic and minerogenetic specialization.
出处
《地学前缘》
EI
CAS
CSCD
1999年第2期305-313,共9页
Earth Science Frontiers
基金
国家教委博士点基金
关键词
成岩
成矿
专属性
火山-侵入杂岩
热液流体
magmatic and minerogenetic specialization,rare earth e lement, volcanic intrusive complexes,hydrothermal fluid