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贵州太平洞金矿床流体包裹体特征及流体不混溶机制
Characteristics of fluid inclusions and fluid immiscibility mechanism of the Taipingdong gold deposit,Guizhou.
【摘要】 太平洞金矿床是兴仁-安龙金矿带灰家堡金矿区的重要卡林型金矿之一。流体包裹体研究证明,石英-黄铁矿阶段(Ⅰ)、石英-黄铁矿-毒砂阶段(Ⅱ)、石英-方解石-雄黄阶段(Ⅲ)的包裹体类型丰富,以气液水两相包裹体、CO2-H2O包裹体和纯液相水包裹体为主,CO2两相包裹体、纯气相有机质包裹体和有机质-H2O包裹体次之,偶见气液有机质包裹体。由Ⅰ→Ⅱ→Ⅲ阶段,气液水包裹体均一温度(200~260℃→180~240℃→100~160℃)呈现逐渐降低的趋势。在Ⅰ阶段的石英中,只在局部偶见到CO2-H2O包裹体和气液两相水包裹体共生;在Ⅱ阶段的石英中,纯液相水包裹体、气液两相盐水包裹体、CO2-H2O包裹体、CO2包裹体及纯气相有机质包裹体共存,它们共生在同一平面中且气液两相盐水包裹体和CO2-H2O包裹体测温数据相差不大,说明当时捕获的是不均匀成矿流体,它是由含有机质的成矿流体经历了CO2-低盐度水的不混溶作用形成的。因而认为,太平洞金矿床中成矿早期流体不混溶作用不明显,主成矿阶段流体的不混溶作用是导致金矿质沉淀的重要原因。
【Abstract】 The Taipingdong gold deposit lies in the Xingren-Anlong gold belt of the Huijiabao gold district.The research on fluid inclusions indicates that various types of fluid inclusions are formed in quartz-pyrite(stageⅠ),quartz-pyrite-arsenopyrite(stage Ⅱ) and quartz-calcite-realgar(stage Ⅲ),which include mainly liquid-rich two-phase inclusions,CO2 inclusions,mono-phase aqueous inclusions and CO2-H2O inclusions,subordinately mono-phase organic vapor inclusions,and minor liquid-vapor organic inclusions are present in minerals of different stages.The homogenization temperature of the aqueous fluid inclusions decreases from stageⅠ(200 ~ 260℃),through stageⅡ(180 ~ 240℃) to Ⅲ(100 ~ 160℃).In quartz of stageⅠ,CO2-H2O inclusions occasionally coexist with twophase aqueous inclusions locally.The coexistence of two-phase aqueous inclusions with simultaneously trapped CO2 inclusions,monophase aqueous inclusions and CO2-H2O inclusions,mono-phase organic vapor inclusions and liquid-vapor organic inclusions in quartz of stage Ⅱ and the similar homogenization of two-phase aqueous and CO2-H2O inclusions suggests that the ore-forming fluid experienced fluid immiscibility between CO2 and low-salinity water.This indicates that fluid immiscibility extensively took place at later stage.The immiscibility of ore-forming fluids between CO2 and low-salinity water caused Au mineralization in the Tai pingdong gold deposit during the main mineralization stage.
【Key words】 Fluid immiscibility; Fluid inclusion; Ore-forming fluids; The Taipingdong gold deposit;
- 【文献出处】 岩石学报 ,Acta Petrologica Sinica , 编辑部邮箱 ,2012年05期
- 【分类号】P618.51
- 【被引频次】30
- 【下载频次】690