江西武山花岗闪长斑岩中黑云母成分特征及其成岩成矿意义  

COMPOSITIONAL CHARACTERISTICS OF BIOTITES IN WUSHAN GRANODIORITE,JIANGXI PROVINCE: IMPLICATIONS FOR PETROGENESIS AND MINERALIZATION

作　　者：东前[1] 杜杨松[1] 曹毅[1] 庞振山[2] 宋林旭[1] 郑震[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,地球科学与资源学院,北京100083 [2]中国地质调查局发展研究中心,北京100037

出　　处：《矿物岩石》2011年第2期1-6,共6页Mineralogy and Petrology

基　　金：自然科学基金(40672045);中国地质调查局项目(20089938);教育部科学技术研究重点项目(308006)

摘　　要：江西武山花岗闪长斑岩与矽卡岩铜矿在成因上密切相关,通过对其中的黑云母进行的岩相学观察和详细的矿物化学分析来探讨黑云母的形成条件及其成岩成矿意义。电子探针分析结果表明,武山花岗闪长斑岩中的黑云母富镁贫铁低铝高钛,属镁质黑云母。其AlⅥ为0.03~0.19,w(ΣFeO)/w(ΣFeO+MgO)为0.531~0.567,w(MgO)为12.80%~14.06%,指示武山花岗闪长斑岩属壳幔混源的I型花岗岩。黑云母结晶的温度为720℃~750℃,logfO2为-11.6^-12.5,压力为86 MPa^103 MPa,对应的侵位深度为2.84 km^3.39 km,表明该岩体形成于相对高温较浅环境,具有较大成矿潜力,有利于武山铜矿的形成。Wushan skarn copper deposit is associated with Wushan granodiorite in genesis.In this paper,we petrographic and mineralogical characteristics of the biotites in Wushan granodiorite are investigated,and its forming conditions and the significance for petrogenesis and mineralization are discussed.Electron microprobe analysis（EPMA） shows that the biotites,which belong to Mg-biotites,are relatively rich in Mg and Ti and poor in Fe and Al.The ionic coefficient of AlⅥ is 0.03~0.19,the ratios of w（ΣFeO）/w（ΣFeO＋MgO）are 0.531~0.567,and the contents of MgO are 12.80%~14.06%.These characteristics implicate that Wushan granodiorite belongs to I-type granite.The crystallization temperature（T） and oxygen fugacity（logfO2） of the biotites are 720 ℃~750 ℃ and-11.6^-12.5,respectively.The solidification pressure（P） of the biotites is 86 MPa^103 MPa,corresponding to solidification depth（H） of 2.84 km^3.39 km.These crystallization conditions indicate that Wushan granodiorite,which was formed in high temperature and oxygen fugacity,has a large mineralization potentiality and is benefit for the formation of Wushan copper deposit.

关 键 词：黑云母 花岗闪长斑岩 矿物化学 成岩成矿 江西武山 

分 类 号：P588.121[天文地球—岩石学] P575.1[天文地球—地质学]