大横路式钴(铜)矿床地质特征及成因探讨

GEOLOGICAL CHARACTERISTICS AND GENESIS OF THE DAHENGLU TYPE COBALT (COPPER) DEPOSITS, JILIN PROVINCE

大横路式钴(铜)矿床产于辽吉古元古代裂谷增生地体内,是国内新近发现的新类型钴矿床,其矿化特征独特、埋藏浅、规模大,具有较高潜在经济价值。矿床赋存于老岭群富硼、碳粘土岩夹硅质岩建造之中,矿体呈层状、似层状、鞍状产出,产状与围岩一致;矿石中金属矿物以硫化物、砷化物形式存在,钴以硫钴镍矿、辉砷钴矿、方钴矿和含钴黄铁矿等形式与黄铜矿、闪锌矿、方铅矿等共生。通过对矿床地质、地球化学特征和流体特征研究,证明该矿床既具有明显的热水沉积成因特征,又受后期变质热液的强烈叠加,属海底热水沉积—变质热液叠加改造型矿床。

Dahenglu type cobalt deposits occur in accretionary terrain of Liaoning-Jilin Proterozoic rifting zone, and are new type cobalt deposit in recent years in China. The deposits are shallow-seated with large scale, and possess unique mineralizing characteristics and potential economic value. This type of deposits is hosted in a formation of B-rich and C-rich clayrocks intercalated with quartzite or siliceous rocks of the early Proterozoic Laoling group. The orebodies present as bed or saddle concordant with wallrocks. Ore minerals exist as sulfides and arsenides. Cobalt in the ores occurs as independent minerals, such as siegenite, cobaltite ckuttreudite and Co-bearing pyrite and others, intergrowth with chalcopyrite, sphalerite and galena. Research results on ore deposit geochemistry indicate that the deposits are of obvious genetic characteristics of submarine hot water deposition and also sustained intensely reformed by later metamorphic solutions.