新疆西准噶尔包古图中酸性岩体氟地球化学研究

Fluorine geochemistry of Baogutu intermediate-acidic intrusive bodies,West Junggar,Xinjiang

氟是岩浆-热液作用过程中常见的矿化剂元素,对成矿过程的理解至关重要。新疆西准噶尔包古图地区产出斑岩型铜矿床,Ⅰ、Ⅱ、Ⅲ-1号岩体矿化程度差,金属矿物体积分数<1%,表现为浸染状分布的黄铜矿、黄铁矿和磁黄铁矿;Ⅲ-2号岩体矿化中等,金属矿物体积分数1%~5%,主要为黄铜矿、黄铁矿和磁黄铁矿,少量毒砂、辉钼矿、斑铜矿、黝铜矿、闪锌矿和银金矿。V号岩体产出大型斑岩铜矿床,矿石样品金属矿物体积分数>15%,浸染状和硫化物脉体常见。样品氟含量测试结果显示,弱矿化花岗闪长岩的氟含量为(300~512)×10^(-6),平均为394×10^(-6),中等矿化花岗闪长岩和石英闪长岩的氟含量为(287~573)×10^(-6),平均为427×10^(-6),斑岩铜矿矿石样品的氟含量为(466~811)×10^(-6),平均为639×10^(-6),明显高于弱矿化和中等矿化样品。随氟含量升高,样品的铜含量逐渐升高,指示氟对铜在流体中的迁移有利。

Fluorine, one of the most common mineralizer, is important for understanding the magmatic- hydrothermal mineralization process. There is one porphyry copper deposit in Baogutu area, West Junggar, Xinjiang, in which the intrusion Ⅰ , Ⅱ and Ⅲ-1 developed a small amount of disseminated chalcopyrite, pyrite and pyrrhotite, reflecting a weak mineralization character （the content of metal mineral 〈1 VoL % ）. Intrusion Ⅲ-2 has a medium-level of mineralization, with disseminated pyrite, pyrrhotite, chalcopyrite and minor arsenopyrite, molybdenite, bornite, tetrahedrite, sphalerite and electrum （the content of metal mineral 1 Vol. %- 5 Vol. %）. Intrusion V developed large-scale porphyry copper deposit, the content of metal mineral 15 Vol. % in ores, with plenty of disseminated and veinlet structures. The fluorine content of weakly, moderately and strongly mineralized intrusions are 300 ）〈 10 -6 512 × 10-6 （average value of 394 ×10 6 ）, 287×10-6- 573×10 6 （average value of 427× 10-6） and 466 ×10-6- 811× 10 6 （average value of 639× 10-6） respectively. Obviously higher values in strongly mineralized intrusions signify the importance of fluorine during the magmatic-hydrothermal mineralization process. In addition, higher fluorine content well coincides with copper mineralization, suggesting that fluorine is helpful in copper migration.