摘要
哀牢山北段金矿成矿带位于扬子地台西部边缘,长100 km。受区域性滑脱构造带、石炭系变基性火山-沉积岩系和无序蛇绿岩带的复合带控制。北西向之脆-脆韧性剪切带与东西向逆冲断裂带的交汇部位,是形成矿田、矿床的最佳地段;矿体常赋存在上述两组断裂的次级断裂及其派生的层间破碎带中。成矿带南段的近矿围岩蚀变以强硅化为主,北段以绢云母化、碳酸盐化及去硅作用为特色。五角十二面体黄铁矿化和毒砂化则是金矿化的显著标志。成矿阶段划分为:(1)交代石英岩阶段;(2)早期硅化阶段;(3)黄铁矿碳酸盐绢云母化阶段;(4)黄铁矿碳酸盐化阶段:(5)多硫化物硅化阶段。包裹体之均一温度280-110℃成矿深度1.11—2.67km,成矿流体为H_2O-CO_2 -NaCl溶液及SO^(2-)_4 性质的钠质溶液,并地质条件、稀土配分、稳定同位素及矿物包裹体研究,将带内金矿床划分为火山-次火山热液型、变质热液型、蚀变超基性岩型、岩浆热液型、残余(铁帽)型等五类。主要金矿床为多期多阶段、多物源、多成因的中-深成矿条件(作用)卜的中温热液矿床。
The gold metallogenic belts in northern section of the Mt. Ailao occur along the eastern side of the Jiujia-Mojiang deep/large fracture, being more than 100 km long. To the south area and north area of Shuanggou, the mi-neralizations are different; the alterations of country rocks were mainly the strong silicification in the former whereas the sericite and carbonatization in the latter. The gold-ore types and their paragenetic associations here include: the gold-ore deposits of the volcanic—subvoleanic hydrothermal type, metamor-phic hydrothermal type, altered ultrabasic rock type(underground water lea-ching type of mixed solution), magmatic hydrothermal type and residual(go-ssan)type. These discoveries break down the pattern of prospecting that men should take the silicification along the endo-, exo-metamorphic zones of the ultrabasic rock as the chief ore guide of prospecting thus enlarging the pro-spects of ore-finding. The formation of the gold metallogenic belts in northern section of Mt. Ailao and ore deposits enriched from the ore belts experienced secular geolo-gical evolution. Repeat action on the identical geological structure zone of the polycyclic tectonic movements, polyphasic mineralizations, polyphyletic source materials and polygenetic ore-bearing hydrothermal as well as the repeat mo-bilization, migration, gathering and precipitation of gold were the prerequisite in forming the gold fleposits of this region. An decisive metallogenic stage took place in late Yanshanian to early Himalayan movement, at that period, the huge scale shear zone was formed by remobilization of the NW—SE striking fracture group of the Jiujia-Mojiang, Ailaoshan and Honghe etc., the huge volume of well rocks(gold source-bed) provide the shear zone with active ele-ments and conduct them towards the surfacial bed through the structure as passageway for ore fluid, finally locate to form the gold ore deposits.
出处
《云南地质》
1991年第1期44-70,共27页
Yunnan Geology
