香花岭花岗岩型铌钽矿床的成因——兼论超临界流体在成岩成矿过程中的作用  

Gensis of Granitic Nb-Ta Deposit in Xianghualing Area and the Role of the Supercritical Fluid in the Process of Rock-forming and Mineralization

作　　者：邱瑞照[1] 彭松柏[1] 杜绍华[1] 

机构地区：[1]中国地质科学院宜昌地质矿产研究所

出　　处：《湖南地质》1997年第2期92-97,共6页Hunan Geology

基　　金：国家自然科学基金青年基金

摘　　要：香花岭花岗岩不同岩相的岩石化学、微量元素、元素对比值和包裹体温度、压力与成分等方面的研究表明：香花岭花岗岩为Ｈ２Ｏ－Ｆ－ＣＯ２－Ｃｌ流体类型，属超临界流体。在超临界流体作用下，岩浆体系内熔体的粘度、内压、组分活动性及含量，随岩浆演化呈系列变化，导致岩浆体系内的成分强烈分异成层；Ｎｂ、Ｔａ等成矿元素，随岩浆体系内超临界流体的聚集而富集，随体系内射气分异作用的发生而矿化，成矿作用发生在岩浆期。其成岩成矿作用为一连续过程。在这一过程中，岩浆的结晶分异作用和交代、熔蚀作用并存，沉淀作用和溶解作用交替。The author has studied the petrochemistry,trace elements,the ration of element pairs,and chemical composition,temperature and pressure of fluid inclusions in the deposit,and concluded that H 2O-F-Cl-CO 2 fluid in Xianghualing granite belongs to the supercritical fluid.Under the action of the supercritical fluid,a serieds of physical and chemical properties including viscosity,inner pressure,mobility and contents of components in magmatic system change systematically with the evolution of magma,from early to late stages,resulting in intensive differentiation and layering of magmatic components.In the mean while Nb,Ta and other ore-forming elements become richer and richer and cause the mineralization as the supercritical fluid concentrates progressively during the magma's evolution and as the emanation-differentiation occur within the magma system.In shor mineralization come out in magmatic stage.Mineralization and rock-forming is a successive proccess in which fractional crystallization of magma and metasomatism and resorption coexist,and precipitation and dissolution take place alternatively.In other words the formation of granitic Nb-Ta deposit in Xianghualing area is in fact a process of differentiation or self-organization in magmatic system under the action of supercritical fluid.

关 键 词：铌矿床 钽矿床 花岗岩型 矿床成因 

分 类 号：P618.790.1[天文地球—矿床学] P618.860.1[天文地球—地质学]