460大型铀-钼矿床成矿地质特征及成因探讨

460铀-钼矿床是冀北沽源中生代火山岩盆地中找到的一个大型中低温热液斑岩型铀-钼矿床。文中阐述了该铀-钼矿床的地质特征,从区域成矿迁移过程和演化历史分析的角度,结合蚀变元素地球化学特征研究,对成矿物质来源进行探讨;总结了矿床的3个主成矿期（24、88和122Ma）,具有斑岩型、浸染型、网脉型和表生铀矿化3种矿化类型。对矿床特征及成因进行探讨。通过研究新近纪表生淋积作用在矿体上部地表处附近形成的次生富集带,总结出冀北火山岩地区铀-钼地质找矿工作靶区的判别依据,明确了寻找此类型铀-钼矿床或盲矿体的直接标志。

Discussion on metallogenic characteristics and genesis of large U-Mo deposit No.460

U-Mo deposit No.460 is a large meso-epithermal porphyre-type U-Mo deposit in Mesozoic volcanic basin in Guyuan of northern Hebei Province.This paper describes the characteristics of U-Mo deposit No.460 in the migration process of regional metallogenic matters and historic evolution,discusses the sources of metallogenic matters with geochemical characteristics of alteration elements.Three major mimeralizaion periods are summarized at 24 Ma,88 Ma and 122 Ma.The mineralization includes porphyre-type,dissemination type,network type and supergene leaching type.The supergene infiltration in Neogene period resulted in the formation of a secondary enrichment zone in the upper part of the orebodies near the surface.Based on the above study,diagnostic evidences and direct criterion are defined for searching the same type U-Mo deposit or blind orebodies in Guyuan of northern Hebei Province.