摘要
双河金矿床位于华北克拉通南缘的卢氏金多金属矿集区,为一石英脉型金矿;矿体呈脉状产于中元古代宽坪群石英二云母片岩切层断裂中;金主要产在黄铁矿和多金属硫化物石英/铁白云石脉中。以含金石英矿脉为中心由内到外围岩蚀变主要发育硅化、黄铁矿化及碳酸盐化。流体成矿过程包括早、中、晚3个阶段,分别以无矿白石英、石英-黄铁矿-多金属硫化物-铁白云石组合和石英-方解石组合为标志,矿石矿物主要沉淀于中阶段。双河金矿流体包裹体类型丰富,不同成矿阶段的流体包裹体主要有H_2O-CO_2包裹体、H_2O包裹体、含子晶(NaCl、CaCO_3)包裹体和含C单质包裹体。显微测温学研究表明,成矿早阶段乳白色石英中包裹体类型有H_2O-CO_2包裹体和H_2O包裹体,H_2O-CO_2包裹体均一温度为220～350℃,盐度为3. 89%～16. 55%NaCleqv; H_2O包裹体均一温度介于220～285℃之间,盐度为1. 40%～1. 70%NaCleqv。成矿主阶段烟灰色石英中包裹体类型包括H_2O-CO_2包裹体、H_2O包裹体、含NaCl子晶包裹体和含C单质包裹体,其中H_2O-CO_2包裹体均一温度为189～345℃,盐度为3. 33%～20. 23%NaCleqv; H_2O包裹体的均一温度介于180～348℃之间,盐度为0. 88%～14. 97%NaCleqv;含NaCl子晶包裹体均一温度为210～359℃,盐度为30. 92%～42. 50%NaCleqv。氢氧同位素研究表明成矿流体来自岩浆水与变质水(δ^(18)O_水=5. 3‰～8. 6‰,δD=-72. 6‰～-38. 4‰);热液碳酸盐的δ^(13)C_(V-PDB)值为-7. 5‰～-5. 2‰,δ^(18)O_(V-SMOW)值为14. 7‰～17. 0‰。包裹体及C-H-O同位素的研究表明,流体的沸腾及水岩反应可能是双河金矿金沉淀的主要原因。
Shuanghe Au deposit is a lode gold deposit in the Lushi polymetal mineralization area,located in the southern margin of North China Craton. The Au-bearing veins occur in the fault,cutting the quartz two-mica schist stratum of the Kuanping Group in the Middle Proterozoic. Gold occurs mainly in pyrite-and polymetallic sulfide-quartz/ankerite vein. The alteration ranges outwardly from silicification,pyritization,and carbonation alteration zones with increasing distance from the ore body. The hydrothermal ore-forming process includes the early,middle and late stages,characterized by mineral assemblages of milk white quartz,quartz-pyrite-polymetal sulfides-ankerite and quartz-calcite,respectively. Ore minerals were mainly precipitated in the middle stage. Types of fluid inclusions in this deposit are various,among which the main types are H2O-CO2 inclusions,aqueous inclusion,liquid-rich inclusions and daughter minerals( NaCl,CaCO3)-bearing inclusions and carbon-bearing inclusions. The fluid inclusions in the early stage milk white quartz are mainly composed of H2O-CO2 inclusions and primary aqueous inclusion. Microthermometric measurements show that the homogenization temperatures of H2O-CO2 inclusions range from 220℃ to 350℃ with salinity of 3. 89% ~ 16. 55% NaCleqv.Homogenization temperatures of aqueous inclusions have homogenization temperatures ranging from 220℃ to 285℃ with salinity of1. 40% ~ 1. 70% NaCleqv. The fluid inclusions in the smoky gray quartz of the main ore stage are mainly composed by H2O-CO2 inclusions,primary aqueous inclusion,NaCl-bearing inclusions and C-bearing inclusions. Microthermometric data show that the homogenization temperatures of H2O-CO2 inclusions range from 189℃ to 345℃,with salinity of 3. 33% ~ 20. 23% NaCleqv.Homogenization temperatures of aqueous inclusions range from 180℃ to 348℃,with salinity of 0. 88% ~ 14. 97% NaCleqv. The NaClbearing inclusions have homogenization temperatures ranging from 210℃ to 359℃,with salinity of 30. 92% ~ 42. 50% NaCleqv.Oxygen and hydrogen isotopes indicate magmatic and metamorphic fluid sources( δ18OH2O= 5. 3‰ ~ 8. 6‰,δD =-72. 6‰ ^-38. 4‰). The δ13CV-PDB and δ18OV-SMOW of hydrothermal carbonate are respectively-7. 5‰ ^-5. 2‰ and 14. 7‰ ~ 17. 0‰. The study of fluid inclusions and C-H-O stable isotopes implies that the boiling of the magmatic fluid and the fluid-rock interaction possibly led to the Au precipitation of Shuanghe Au deposit.
作者
高帅
曾庆栋
褚少雄
周天成
范宏瑞
程占东
马留锁
GAOShuai;ZENGQingDong;CHUShaoXiong;ZHOUTianCheng;FANHongRui;CHENGZhanDong;MALiuSuo(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institutions of Earth Science,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China;Lushi County Bureau of Land and Resource,Lushi 472200,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2018年第12期3539-3552,共14页
Acta Petrologica Sinica
基金
国家自然科学基金重大计划项目(91514301)
岩石圈演化国家重点实验室自主研究课题(专201606)联合资助.
关键词
流体包裹体
稳定同位素
双河金矿
华北克拉通南缘
Fluid inclusions
Stable isotopes
Shuanghe Au deposit
Southern margin of North China Craton
