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桂北牛塘界钨矿位于南岭西段,地处广西北部资源县和兴安县交界处,属层状矽卡岩型白钨矿床,岩株状细粒二云母花岗岩在时空上与其有密切的联系.利用LA-ICP-MS锆石U-Pb原位定年方法,获得花岗岩的侵位年龄为(421.8±2.4)Ma,与相邻的越城岭花岗岩体同属于加里东期岩浆活动产物.含钨矽卡岩中主要脉石矿物为石英、石榴子石和透辉石等.矿物组合显示,白钨矿的形成经历了两个阶段:石英-白钨矿阶段和石英-硫化物-白钨矿阶段.对矽卡岩中的白钨矿进行了Sm-Nd同位素分析,获得了钨成矿年龄为(421±24)Ma,虽然该数据误差较大,但仍清楚表明岩体与成矿作用都发生在加里东期.花岗岩中锆石的εHf(t)值为-6.5~-11.6,Hf同位素两阶段模式年龄为1.79~2.11 Ga,说明花岗岩的源区可能为中元古代的地壳物质.矽卡岩中白钨矿的εNd(t)为-13.06~-13.26,说明其成矿流体也来源于古老的地壳物质.研究表明,在南岭地区西段存在的加里东期岩浆活动为加里东期的钨成矿作用提供了物源.
Located in the western part of Nanling, the Niutang sector of tungsten ore in northern Guangxi is located in the junction of Ziyuan County and Xing’an County in the north of Guangxi. It belongs to a layered skarn-type scheelite deposit and the rock-like fine-grained micaceous granite is closely related in time and space The in-situ dating of granite by LA-ICP-MS zircon U-Pb in situ dating was (421.8 ± 2.4) Ma, which was the same as the Caledonian magmatic activity of the adjacent Yuechengling granite The main gangue minerals in tungsten-bearing skarns are quartz, garnet, diopside, etc. The mineral assemblages show that the scheelite undergoes two stages: the quartz-scheelite stage and the quartz-sulfide-white Tungsten ore stage. The Sm-Nd isotope analysis of scheelite in skarn resulted in a tungsten mineralization age of (421 ± 24) Ma. Although the data show a large error, it is still clear that the rock mass and The mineralization takes place in the Caledonian period. The εHf (t) values of zircons in granites range from -6.5 to -11.6, and the Hf isotopic two-stage model ages from 1.79 to 2.11 Ga suggest that the source area of granites may be the Proterozoic crust The εNd (t) of scheelite in skarn is -13.06 ~ -13.26, indicating that the ore-forming fluid is also derived from the ancient crustal material. Show, in the western part of the region Nanling exist Caledonian magmatism provide a source for the mineralization was Caledonian tungsten.