胶西北中生代花岗岩中黑云母和角闪石成分特征及成岩成矿意义  

Chemical composition of biotite and amphibole from Mesozoic granites in northwestern Jiaodong Peninsula,China,and their implications

作　　者：杨阳[1] 王晓霞[1] 于晓卫[2] 柯昌辉[1] 王立功[2] 郭瑞朋[2] 王顺安[1] 李小霞[3] YANG Yang WANG XiaoXia YU XiaoWei KE ChangHui WANG LiGong GUO RuiPeng WANG ShunAn LI XiaoXia(MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, CAGS, Beijing 100037, China Shandong Institute of Geological Survey, Ji＇ nan 250013, China Exploration and Devolopment Research Institute of Henan Olifield Branch Company, SINOPEC, Zhengzhou 450000, China)

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 [2]山东省地质调查院,济南250013 [3]中国石化河南油田分公司勘探开发研究院,郑州450000

出　　处：《岩石学报》2017年第10期3123-3136,共14页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2017YFC0601403);山东省地质勘查项目(鲁国土资发[2014]262);地质调查项目(1212010611803)资助

摘　　要：在详细的野外地质和岩相学观察基础上,对胶西北中生代玲珑期、郭家岭期和伟德山期花岗岩中的黑云母和角闪石进行了系统的化学成分研究。结果显示,玲珑期,研究区中部和南部花岗岩中的黑云母为铁叶云母和铁质黑云母,其MgO为4.07%~6.53%,具有壳源型黑云母的特征;北部主要为铁质黑云母和镁质黑云母,MgO介于9.13%~11.57%之间,具壳幔混源型的特征;郭家岭期和伟德山期花岗岩中的黑云母以铁质黑云母和镁质黑云母为主,MgO为7.62%~15.38%,均为壳幔混源型,其中的角闪石均属于钙质角闪石,M值为0.44~0.76。暗色矿物成分显示玲珑期花岗岩的源区物质主要为壳源,郭家岭期和伟德山期的以壳源为主,有少量幔源组分参与。三期花岗岩中黑云母结晶温度主要集中于550~700℃,而角闪石的结晶温度为600~750℃,从玲珑期到郭家岭期再到伟德山期,即从早到晚,黑云母的结晶温度有升高的趋势;全铝压力计估算结果显示,黑云母和角闪石的结晶压力具有降低的趋势。郭家岭期和伟德山期花岗岩中黑云母结晶过程中的氧逸度分别为-15.0^-9.0和-15.3^-8.8,明显比玲珑期的(-17.5^-13.2)高。结合胶西北金矿的时空分布特征,认为花岗岩结晶过程中较高的氧逸度和幔源物质的参与可能是有利于金矿化的重要条件之一。Based on field geological and petrographic observation,this paper provides systematic chemical composition study on biotite and amphibole from Mesozoic granites of Linglong,Guojialing and Weideshan periods in northwestern Jiaodong Peninsula.The results show that the biotite from the granites in central and southern parts of the study area of Linglong period is siderophyllites and Febiotite,and its MgO content is 4.07%~6.53%,showing characteristics of crust affinity,while the biotite from the granites in northern part of the study area is Fe-biotite and Mg-biotite with MgO of 9.13%~11.57%,showing characteristics of crust-mantle affinity.The biotite from the granites of Guojialing and Weideshan periods belong to Fe-biotite and Mg-biotite with MgO from 7.62% to15.38%,revealing crust-mantle features.The amphibole from the granites of these two periods is calcic group with M [Mg/（Mg＋Fe^（2＋））]value ranging from 0.44 to 0.76.Mineral compositions suggest that the source of Linglong granites is crust while the sources of Guojialing and Weideshan granites are crust with contribution of mantle components.Biotite and amphibole from these granites crystallized under temperature of 550~700℃ and 600~750℃,respectively.The crystallization temperature of biotite is increase,while the pressure of biotite and amphibole is decrease fromLinglong to Weideshan period.The oxygen fugacity of biotite from Guojialing and Weideshan granites are -15.0^-9.0 and -15.3^-8.8,respectively,being significantly higher than that of Linglong granites（logf（O2）=-17.5^-13.2）.According to the spatio-temporal distribution of the gold deposits in northwestern Jiaodong Peninsula,contribution of mantle components and high oxygen fugacity of these granites seem to be favourable for gold mineralization.

关 键 词：矿物化学成分 结晶条件 中生代花岗岩 金矿化 胶西北 

分 类 号：P575.1[天文地球—矿物学] P578.955[天文地球—地质学]