北秦岭成矿带普洛河地区铀矿化特征及控矿因素分析

Uranium Mineralization Characteristics and Ore-Controlling Factors in the Puluohe Area of the North Qinling Metallogenic Belt

摘要: 普洛河地区发育花岗岩外带和内带型铀矿化类型，两者地质、矿化特征基本相同，产在接触带2 km范围内，矿体呈扁豆状、呈细脉状，长 < 400 m，有多层性，铀矿物主要为沥青铀矿、铀石，镶边结构、环带结构，细脉、网脉状构造、角砾状构造，矿化厚度薄、中低品位，成矿年龄为98 ± 4 Ma，相当于晚白垩世。铀矿化受构造控制作用明显，高楼大断裂和普洛河断裂控制四个矿化集中区的定位，次级断裂为深部热液提供运移通道，低级别构造破碎带和裂隙密集带提供矿体赋存空间；指出赤铁矿化–绿泥石化–黄铁矿化、硅化–黑紫色萤石化、赤铁矿化–黄铁矿化–绢英岩化为区内重要的矿化蚀变组合；建议大底村904~雨源沟903、碾盘沟8099~寺院沟23为今后工作重点勘查地段，黄家庄8050~上坪201为探索地段。

Abstract: Granite outer and inner-type uranium mineralization developed in the Puluohe area. Their geo-logical and mineralization characteristics are basically the same, and they are produced within 2 km of the contact zone. The ore body is lenticular, fine veined, less than 200 m in length, and multi-layered. Uranium minerals are mainly pitchblende and coffinite which are the mosaic and zonal textures, fine vein, network vein and breccia structures. The mineralization is thin, me-dium and low grade, and the mineralization age is 98 ± 4 Ma, which is equivalent to the Late Cretaceous. Uranium mineralization is obviously controlled by tectonics. The Gaolou large fault and the Puluohe fault control the location of the four mineralization concentration zones, and the secondary faults provide channels for deep hydrothermal migration. The low-level structur-al fracture zone and the fractured dense zone provide space for the ore body. It is pointed out that hematitization-chloritization-pyritization, silicification-black purple fluorite, hematitiza-tion-pyritization-sericite-quartz alteration are important mineralization alteration combinations in the region. It is suggested that Dadi Village 904-Yuyuangou 903, Nianpangou 8099-Siyuangou 23 are the key exploration areas for future work, and Huangjiazhuang 8050-Shangping 201 is the exploration area.