摘要
上房沟钼矿床位于栾川断裂带北侧的华北克拉通南缘,矿体赋存于晚元古代栾川群碎屑岩-碳酸盐建造中。钼成矿经历了早、中、晚3个阶段:早阶段为钾长石-石英-辉钼矿-黄铁矿组合,中阶段为石英-辉钼矿-多金属硫化物组合,晚阶段以方解石-石英-萤石脉为特征。流体包裹体可划分为富/含CO_2型、含子矿物型和NaCl-H_2O型3类。早、中成矿阶段发育较多CO_2-H_2O型和含子晶型包裹体,晚阶段为NaCl-H_2O型包裹体。早阶段流体具有高温(320℃～500℃)、高盐度(31.75～66.75wt%NaCl eqv.)、富CO_2的特点,显示浆控高温热液矿床的特征;中阶段流体具有中温(190℃～400℃)、中等盐度(2.07～12.85 wt%NaCl eqv.,个别超过30 wt%NaCl eqv.)、富/含CO_2特点;晚阶段为中低温(160℃～260℃)、低盐度(～4.8 wt%NaCl eqv.)、贫CO_2的NaCl-H_2O体系。早、中阶段流体沸腾作用强烈,造成CO_2不断逸失、流体氧化性降低、成矿物质大量沉淀,是成矿的重要机制。
The Shangfanggou Mo deposit in Henan province is located on the southern margin of North China Craton oil the north of the Luat chuan fault. The deposit is hosted in Luanchuan Group. The molybdenum mineralization process can be divided into early, middle and late three stages, which are characterized by assemblages of potassium feldspar-quartz-molybdenite-pyrite, quartzmolybdenite-polymetallic sulfide, and carbonate-quartz-fluorite, respectively. The fluid inclusions in quartz and carbonate can be recognize as three compositional types, i.e., CO(2)-H(2)O, H(2)O-NaCl and daughter crystal-containg. The primary fluid inclusions in minerals formed in early and middle stages are major of CO(2)-H(2)O and daughter crystal-containing types, while those in late-stage minerals only of H(2)O-NaCl type. The early-stage fluid is hypothermal (320 similar to 500 degrees C), high salinity (31.75 similar to 66.75 wt% NaCl eqv.) and CO(2)-rich and belongs to the typical intrusion-related hypothermal system. In middle stage, the fluid system is mesothermal (190 and CO(2)-rich and belongs to the typical intrusion-related hypothermal system. In middle stage, the fluid system is mesothermal ( 190 similar to 400 degrees C) middle salinity ( mainly between 2.07 similar to 12.85wt% NaCl eqv., minor up to > 30 wt% NaCl eqv. and CO(2) rich or bearing. The late-stage fluid is a CO(2)-poor NaCl-H(2)O system with low temperature ( 160 similar to 260 degrees C and low salinity < 4.8 wt% NaCl eqv.). Fluid holing occurred in early and middle stages, which caused CO(2) escape, oxygen fugacity decrease and rapid precipitation of ore minerals Fluid boiling is an important mechanism for the Mo-mineralization of the Shangfanggou Mo deposit.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第10期2563-2574,共12页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划项目(2006CB403500)
国家自然科学基金项目(40502012,40425006)
高等学校学科创新引智计划(B07011)
地质过程与矿产资源国家重点实验室开放基金(GPMR200835)的资助
