闽北中生代火山岩浆活动与金属成矿的关系

THE RELATIONSHIP BETWEEN MESOZOIC VOLCANIC MAGMATIEM AND METAL MINERALIZATION IN NORTHERN FUJIAN

在岩石学和微量元素地球化学研究的基础上,通过对典型区的解剖,探讨了中生代火山岩浆活动与金属成矿的关系,认为与板块运动两个阶段相对应发育两个不同的金属成矿系列.一个系列与挤压环境内晚侏罗世火山岩浆活动有关,矿质来源有两重性(晚侏罗世火山-岩浆岩和/或围岩),是主要的成矿系列;另一系列与挤压-拉张环境内早白垩世火山岩浆活动有关,成矿发生在火山盆地边缘相对较深的部位.

Based on the study of petrology and geochemistry, the author approached the relationship between Mesozoic volcanic magmatism and metal mineralization by analysing some typical districts, and suggested that two different epochs of ore-forming series corresponding to the two stages of plate movement respectively be developed. The former is more important, with relation to Late Jurassic volcanic magmatism taking place in compressional environment. And its source of ore materials has ambiguity (coming from itself and/or host rocks). This series include mineralization with relation to intermediate acidic rocks (epithermal Au-Ag and Ag-Au base metal, Au-Ag quartz vein, and Au-Ag Au Pb Zn sulfide vein type), and Au-Cu mineralization related to nearly intermediate rocks and having closely spatial association with porphyry bodies and breccia pipes. The latter developed in relatively deep sites along the margin of Early Cretaceous volcanic basins, with relation to Early Cretaceous magmatism in compressional-extensional nvironment. And the ore-forming metal depends on the orebearing characteristics of wall rocks. Cu and Pb-Zn mineralizations are the main components of this series.