云南个旧锡多金属矿集区花岗岩中黑云母的成分特征及成岩成矿意义  

COMPOSITIONAL CHARACTERISTICS AND PETROGENTIC AND METALLOGENIC SIGNIFICANCE OF BIOTITE IN GRANITE IN GEJIU TIN POLYMETALLIC ORE CONCENTRATION AREA,YUNNAN PROVINCE

作　　者：张毓策 陈守余[1,2] 赵江南[1,2] 赵月华 李姜 Zhang Yuce;Chen Shouyu;Zhao Jiangnan;Zhao Yuehua;Li Jiang(School of Earth Resources,China University of Geosciences,Wuhan,Hubei 430074,China;State Key Laboratories of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan,Hubei 430074,China)

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《矿物岩石》2020年第1期76-88,共13页Mineralogy and Petrology

基　　金：中国地质调查局发展研究中心项目“云南个旧老厂东深部资源调查”(DD2016225232)。

摘　　要：黑云母的成分特征对指示岩石成因与成矿起着重要的作用,通过电子探针技术对个旧矿集区花岗岩中黑云母矿物化学研究表明,龙岔河斑状花岗岩、马松斑状花岗岩和神仙水等粒花岗岩中的黑云母属于铁质黑云母,白沙冲等粒花岗岩和老卡等粒花岗岩的黑云母属于铁叶云母。龙岔河岩体、马松岩体、神仙水岩体、白沙冲岩体和老卡岩体的黑云母结晶温度分别为679.57~711.46℃,632.83~711.55℃,572.23~661.61℃,450~620℃和500~708℃。各个岩体的固结压力分别为123.30~155.09 MPa,147.92~258.66 MPa,291.81~361.64 MPa,321.21~489.08 MPa和338.19~469.73 MPa,表明个旧矿集区花岗岩属中深成相。相比于其它岩体,神仙水岩体和白沙冲岩体形成于较高氧逸度条件。w(FeOT)(18.58%~26.91%)、氧化系数(0.390~0.123)和镁质率(0.05~0.54)等特征,表明个旧矿集区花岗岩既有A型花岗岩的特点,也有I型花岗岩的特点。w(MgO)(0.57%~9.27%)表明其岩浆源区有壳幔混源的特点。低氧逸度和高温的花岗质岩浆有利于晚期分异的流体形成锡矿化,马松岩体和老卡岩体与Sn成矿更密切。Chemical analysis of biotite minerals in granites from Gejiu ore concentration area by electron microprobe analyzer(EMPA)indicates that biotite in Longchahe porphyry granite,Masong porphyry granite and Shenxianshui granular granite belongs to ferric biotite,while biotite in Baishachong granular granite and Laoka granular granite belongs to ferrophyllite.The crystallization temperatures of biotite in Longchahe,Masong,Shenxianshui,Baishachong and Laoka rock bodies are 679.57-711.46℃,632.83-711.55℃,572.23-661.61℃,450-620℃and 500-708℃,respectively.The consolidation pressures of each rock body are 123.30-155.09 MPa,147.92-258.66 MPa,291.81-361.64 MPa,321.21-489.08 MPa and 338.19-469.73 MPa,respectively,indicating that the granites in Gejiu concentration area belong to meso-deep facies.Compared with other rock bodies,the Shenxianshui and Baishachong rock bodies were formed under higher oxygen fugacity conditions.Such parameters as w(FeOT)=18.58%-26.91%,oxidation coefficient=0.390-0.123 and magnesium content=0.05-0.54 indicate that the granite in Gejiu ore concentration area is characteristic of both A-type granite and I-type granite,while w(MgO)=0.57%-9.27%suggests that the rock bodies have a crust-mantle mixed magma source.Low oxygen fugacity and high temperature granitic magma are favorable for the formation of tin mineralization in late differentiated fluids.Masong and Laoka rock bodies are more closely related to Sn mineralization.

关 键 词：个旧矿集区 黑云母 成分特征 成岩成矿 

分 类 号：P575.1[天文地球—矿物学] P581[天文地球—地质学]