摘要
广东英德周屋铜多金属矿床位于南岭多金属成矿带,其矿床成因存在矽卡岩型和热液改造型的争议,并且研究程度较低,缺乏较为可靠的证据,尤其成矿流体研究是空白。通过对周屋铜多金属矿床系统的流体包裹体岩相学、显微测温和拉曼分析研究表明:在矽卡岩阶段发育富液相包裹体、富气相包裹体和含子矿物多相包裹体。矽卡岩阶段的石榴石和白钨矿中包裹体均一温度为290~≥490℃,高盐度(35.26%~40.10%NaCl_(eqv))和低盐度富气相包裹体(4.18%~4.96%NaCl_(eqv)),表现出流体不混溶现象,或以富气相和富液相包裹体共存为特征,温度范围为320~490℃,盐度变化范围较大(4.18%~17.08%NaCl_(eqv)),表现为沸腾现象。金属硫化物阶段,在硫化物早期石英中包裹体均一温度为290~360℃,高盐度(30.92%~37.40%NaCl_(eqv))和低盐度富气相包裹体(10.48%~11.70%NaCl_(eqv)),表现出流体不混溶现象;硫化物晚期以富气相和富液相包裹体共存为特征,温度范围为202~320℃,盐度变化范围较大(4.18%~24.04%NaCl_(eqv)),显示流体的沸腾现象,硫化物阶段是铜矿主要成矿阶段。褐铁矿-碳酸盐化阶段的石英和方解石中全部发育富液相包裹体,演化为相对较低的温度(Th=120~220℃)和较低的盐度(2.57%~7.59%NaCl_(eqv)),没有沸腾现象,属于NaCl-H_2O成矿体系。拉曼分析结果表明:早期石榴石、白钨矿和石英中包裹体气相成分以CO_2为主,其次是(或含)CH_4或H_2;液相成分主要为H_2O,晚期石英和方解石中包裹体液相和气相成分主要为H_2O和N_2。从早期的石榴石、白钨矿到晚期的石英和方解石,包裹体中H_2O的含量增多,说明在矽卡岩后期阶段,有较多的天水加入。铜矿床的成矿流体在200~490℃区间内至少发生了2次强烈的沸腾作用,改变了体系内的物理化学条件,导致大量铜的金属硫化物沉淀,沸腾作用对铜矿的形成和富集起着重要作用,为探讨矿床成因提供�
Zhouwu Cu-polymetal deposit in Yingde, Guangdong Province is tectonically located in the Nan- ling metallogenic belt. The Zhouwu deposit is poorly studied, resulting in disagreement on ore formation including skarn-type or hydrothermal metamorphism deposit, and lacking detailed evidence furthermore hampers the understanding of the nature of Cu-polymetal deposit. We conducted systematic petrography, microthermometry and Roman analysis on fluid inclusions of the skarn stage and sulfide stage from the Zhouwu Cu-polymetal deposit in this contribution. Petrography and microthermometry studies suggest that aqueous inclusions, gas-rich CO2-bearing inclusions and daughter mineral-bearing inclusions are domi- nant in the skarn stage. Fluid inclusions hosted in garnet and scheelite of skarn stage yield homogenization temperature （T h） at 290-≥490℃, aqueous inclusions of high salinity （35.26 %-40.10% NaCleqv） and gas-rich CO2-bearing inclusions of high salinity （4.18%-4.96% NaCleqv）, indicating a fluid immiscibility process. The coexisting aqueous inclusions and gas-rich COz-bearing inclusions yield Th at 320-≥490℃, and salinity of a wide range （4.18%-17.08% NaCleqv）, indicating a boiling during their being entrapped. At the early sulfide stage, fluid inclusions hosted in quartz yield Th at 290-360℃, and aqueous inclusions of high salinity （30.92%-37.40% NaCleqv） and gas-rich CO2-bearing inclusions of high salinity （10.48% -11.70% NaCleqv）, indicating a fluid immiscibility process. Whereas the coexisting aqueous inclusions and gas-rich CO2-bearing inclusions of the late sulfide stage display fluid inclusions with Th at 202-320℃, and salinity of a wide range （4.18%-24.04% NaCleqv）, suggesting a boiling during Cu-sulfide precipitation. Fluid inclusions entrapped in quartz and calcite from limonite-earbonatization stage are aqueous-rich, and evolved to be a NaCl-H2O system yielding relatively low Th （120-220℃） and salinity （2. 57%- 7.59% NaCleqv） without boiling. Roman analyses
出处
《地质科技情报》
CSCD
北大核心
2017年第6期122-135,共14页
Geological Science and Technology Information
基金
中国地质调查局地质矿产调查评价专项项目"南岭成矿带中西段地质矿产调查"(1212010090000150002)
关键词
流体包裹体
显微测温
拉曼
铜多金属矿床
周屋
南岭成矿带
fluid inclusion
microthermometry
laser Raman spectroscopy
Cu-polymetal deposit
Zhou-＇wu, Nanling metallogenic belt
