白石顶钼矿床位于湘粤桂交界的桂北姑婆山地区,主要以石英辉钼矿脉的形式产于桂岭岩体(角闪石)黑云母二长花岗岩和南华系浅变质浅海相碎屑岩中.桂岭岩体岩石类型以中-细粒斑状(角闪石)黑云母二长花岗岩为主,岩石呈灰白色,似斑状结构.斑晶主要由微斜长石和斜长石组成,基质则由微斜长石、斜长石、石英、黑云母和普通角闪石组成,副矿物有磁铁矿、锆石、褐帘石、绿帘石、磷灰石、榍石等.白石顶钼矿的矿石矿物主要为辉钼矿、黄铁矿、黄铜矿和白钨矿等.围岩蚀变有黄铁矿化、钾长石化、白云母化、绿泥石化等.文章通过对桂岭岩体及其包体中锆石SHRIMP U-Pb年龄和辉钼矿Re-Os年龄的测定,初步揭示了白石顶钼矿床的成矿年代,桂岭岩体(角闪石)黑云母二长花岗岩锆石SHRIMP UP-b年龄为(424.4±5.6)Ma,其中的闪长质包体的SHRIMP U-Pb年龄为(428±4)Ma.6件辉钼矿Re-Os的加权平均年龄为(424.6±5.7)Ma,这表明白石顶钼矿床形成于志留纪.此次工作首次认为在华南地区志留纪也发生了金属钼的富集成矿,该成果对于深入认识华南地区加里东期的构造.岩浆演化及其成矿作用具有重要的科学价值.%The Baishiding molybdenum deposit is located in northern Guangxi, and its ore bodies occur mainly as quartz + molybdenite veins in Guiling biotite monzogranite and epimetamorphic neritic facies clastic rocks in Nan-hua System. Ore minerals are composed of molybdenite, pyrite, chalcopyrite and scheelite. The Mo grade ranges from 0.1% to 0.3 % with an average of 0.12 %. With the distance from the quartz vein, the monzogranite has been altered into K-feldspar, sericite and chlorite in succession. Molybdenite is precipitated in the quartz vein, mostly occurring along the boundary between the monzogranite and the quartz vein or assuming disseminations in monzogranite. Scheelite is also intergrown with molybdenite in the quartz vein. Six molybdenite Re-Os ages from six samples indicate that mineralization took place in Silurian. Zircon SHRIMP U-Pb dating of Guling biotite monzogranite shows that the granite was emplaced at (424.4 ± 5.6) Ma, whereas the zircon from the enclave has an age of (428 ±4) Ma. These data suggest that the Baishiding molybdenum deposit was formed in Silurian, implying that Mo mineralization did occur in Silurian in South China.
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