东秦岭上宫金矿流体成矿作用:矿物学研究  

HYDROTHERMAL METALLOGENY OF THE SHANGGONG GOLD DEPOSIT,EAST QINLING:EVIDENCE FROM MINERALOGICAL STUDY

作　　者：李晶[1] 陈衍景[1] 李强之[1] 唐国军[1] 

机构地区：[1]北京大学造山带与地壳演化实验室,北京100871

出　　处：《矿物岩石》2004年第3期28-35,共8页Mineralogy and Petrology

基　　金：自然科学基金(49972035和40352003);九五攀登(95-Pre-39-04);教育部跨世纪人才和科学院百人计划项目资助

摘　　要：　通过对上宫金矿矿物学资料的研究,确定其成矿过程具有3阶段演化特征。早阶段以粗粒乳白色石英脉为标志,矿物破碎、变形明显,金和杂质成分含量低,形成于挤压构造背景下静岩压力的变质流体。中阶段发育细粒多金属硫化物-碲化物-自然元素组合,呈微细网脉浸染于共轭节理或裂隙,没有遭受变形,金和杂质成分含量高,自然金与其他矿物属共沉淀关系,由变质流体沸腾导致,而流体沸腾则由造山过程的地壳快速隆升剥蚀引起。晚阶段发育具梳状构造的石英-碳酸盐网脉,含金性较低,由静水压力的大气降水热液在伸展构造背景下贯入张性裂隙形成。矿床地质地球化学特征与造山型金矿一致,成矿过程同步于陆陆碰撞造山作用,属于典型的断控脉状造山型金矿,成因适合于CMF模式。This paper documents the research results in mineralogy for the Shanggong gold depost, E Qinling, China, and defines a three-stage evolution of the hydrothermal metallogenesis. The early stage was marked by milky coloured,coarse-grained quartz veins, in which minerals were obviously broken and deformed with little gold. The early stage mineralization was caused by a lithostatic fluid-system of metamorphic origin in a compressive setting. The middle stage is characterized by fine-disseminated stockworks composed of polymetallic sulfides-tellurides-native elements. The stockworks filled in conjugate joints or other fissures,and show no deformation. Minerals of this generation contain much high gold and non-lattice elements. Native gold and minerals of the generation precipitated coevally in boiling phase of a metamorphic fluid-system. The fluid-boiling event was resulted from rapidly crustal uplift and erosion. The late stage formed comb-like quartz-carbonate veinlets with very low content of Au. In a extensional tectonic setting, input of hydrostatic, meteoric water into extensional fractures resulted in development of late-stage veinlets. Geological and geochemical characteristics of the Shanggong gold deposit was are similar to those of orogenic-type. Metallogenesis of the Shanggong deposit was coeval with continental collision between the Yangtze and North China plates. This shows that the Shanggong deposit is a typical example of orogenic-type gold deposit and its genesis can be interpreted by the CMF model.

关 键 词：金矿 矿物学 流体沸腾 成矿作用 东秦岭 

分 类 号：P618.51[天文地球—矿床学]