康鸿杰,周超,宋学兵,徐茂文,刘晓煌,宁娜.北祁连西段金佛寺岩体接触带青大坂钨钼矿流体包裹体特征及成矿流体演化[J].矿产勘查,2020,11(9):1882-1893 |
北祁连西段金佛寺岩体接触带青大坂钨钼矿流体包裹体特征及成矿流体演化 |
Characteristics of fluid inclusions and fluid evolution of Qingdaban W-Mo deposit on the contact zone of the Jinfosi pluton in the western part of the North Qilian Mountains |
投稿时间:2020-04-21 |
DOI: |
中文关键词: 钨钼矿 成矿流体 流体包裹体 地球化学 金佛寺 |
英文关键词: W-Mo deposit,ore-forming fluid,fluid inclusion,geochemistry,Jinfosi |
基金项目:甘肃省自然科学基金项目(编号:1606RJZA183)资助。 |
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中文摘要: |
青大坂钨钼矿位于金佛寺岩体接触带多金属成矿带中段,其成矿过程可划分为热液期和表生期,其中热液期包括硅酸盐、石英硫化物和石英方解石等3个成矿阶段。本文通过不同成矿阶段流体包裹体岩相学观察和显微测温、包裹体成分分析及氢氧同位素测试等多种研究方法,探讨了成矿流体演化过程。研究表明,从硅酸盐阶段到石英方解石阶段,流体包裹体均一温度从314~521℃,经202~291℃,降低到 126~181℃;盐度从4.20%~13.29% NaCleq,经2.07%~13.51% NaCleq,降低到2.74%~7.17% NaCleq。包裹体激光拉曼探针和群体包裹分析显示,该矿床成矿流体以H2O为主,其气相成分主要为H2O,其次为CO2和N2以及少量的CH4、C2H6、H2S、Ar,液相成分以Na+、K+、Cl-、SO42-为主,含有少量的F-和Ca2+。氢氧同位素特征显示成矿流体为大气降水加入的岩浆水混合热液。本次研究表明,成矿流体的沸腾作用、大气降水的加入和流体还原性增强,是导致大量钨钼等金属矿物不断沉淀成矿的原因。 |
英文摘要: |
Qingdaban W-Mo deposit is located in the middle of the polymetallic metallogenic belt of jinfosi pluton contact zone. The process of ore-forming can be divided into hydrothermal stage and epigenic stage. The hydrothermal stage includes three metallogenic stages:silicification stage, quartz sulfofication stage and quartz carbonation stage. Based on petrographic, mircothermometry, composition analysis and H-O isotopes of fluid inclusion, the evolution process of ore-forming fluid is discussed. From Silicification stage to quartz sulfofication stage,the homogenization temperature and salinity of fluid inclusion decreased from 314-521℃ and 4.20-13.29wt%, through 202-291℃ and 2.07%-13.51%, to 126-181℃ and 2.74%-7.17%. It is confirmed by Laser Raman spectroscopy and group inclusion analysis that the main ore-forming fluid was H2O. The gas phase composition was mainly H2O, followed by CO2 and N2, and the rest was a small amount of CH4, C2H6, H2S and Ar. The liquid phase composition was mainly Na+, K+, Cl-, SO42-, and a small amount of F- and Ca2+. Hydrogen and oxygen isotopes indicate that the ore-forming fluid is a mixture of magmatic water and meteoric water. It is showed that the combined action of boiling, atmospheric water and reducing environment caused a lage amount of precipitation of W, Mo and other metal minerals. |
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