岩浆型矿床黑云母地球化学特征及其地质意义:以河北涿鹿矾山磷矿为例  

Geochemical characteristics and geological significance of biotite in magma type ore deposit:a case study of Fanshan phosphate deposit in Zhuolu County,Hebei Province

作　　者：王振磊 王树志 刘艺 刘建国 杨继锋 张庆利 张子祥 张继敏 WANG Zhen-lei;WANG Shu-zhi;LIU Yi;LIU Jian-guo;YANG Ji-feng;ZHANG Qing-li;ZHANG Zi-xiang;ZHANG Ji-min(College of Mining Engineering,North China University of Science and Technology,Tangshan 063210,Hebei,China;School of Resources and Environment Engineering,Shandong University of Technology,Zibo 255012,Shandong,China;Hebei Fanshan Phosphate Ore Co.Ltd.,Zhangjiakou 075641,Hebei,China)

机构地区：[1]华北理工大学矿业工程学院,河北唐山063210 [2]山东理工大学资源与环境工程学院,山东淄博255012 [3]河北省矾山磷矿有限公司,河北张家口075641

出　　处：《世界地质》2021年第2期288-297,共10页World Geology

基　　金：河北省自然科学基金项目(D2019209531);华北理工大学大学生创新创业训练计划项目[X2019210]联合资助。

摘　　要：为确定黑云母矿物在岩浆型矿床形成过程中所发挥的作用,选取矾山磷矿产出的黑云母矿物为研究对象,利用岩相学和地球化学结合的方法进行研究。根据黑云母矿物的富水特点,采集了矾山杂岩体和铁磷矿体中的黑云母进行测试。岩相学上,黑云母矿物有轻微蚀变、交代现象;黑云母化学组分呈现高Al低Ti,符合热液型矿床黑云母组分特点;同时,黑云母的Al_(2)O_(3)/TiO_(2)=4.52,>3.5、<<7并且Fe^(2+)/(Fe^(2+)+Mg^(2+))比值不均一,这些都表明矿床具有热液型特征。结合前人研究成果,认为在矾山杂岩体中岩浆型黑云母与热液型黑云母并存。经地球化学分析,矾山杂岩体中的黑云母Fe^(2+)/(Fe^(2+)+Mg^(2+))为0.37~0.69,全铝(TAl)为2.594~3.129。黑云母成分记录显示:岩浆-流体转化体系中的氧逸度较高,温度也较高,黑云母表现为富铁特征,进一步表征了铁矿形成原因。综合研究认为,矾山磷矿黑云母具有高温、高氧逸度和高挥发组分的特点,这也是矾山杂岩体发育铁磷矿的原因。In order to determine the significance of biotite in the formation of magma type deposits,biotite in Fanshan phosphate deposit is studied by combining petrography with geochemistry.According to the water-rich characteristics,biotites from both Fanshan complex and Fe-P ore body are selected for testing.Some biotites show lower degree of alteration and metasomatism in petrography.The chemical compositions show high contents of Al and low Ti,indicating hydrothermal genesis for the deposit.Moreover,the ratio of Al_(2)O_(3)/TiO_(2) is 4.52,>3.5,<<7,with inhomogeneous Fe^(2+)/(Fe^(2+)+Mg^(2+)),indicating charactcristics of hydrothermal deposit.Based on previous research,it can be inferred that magmatic biotites and hydrothermal biotites coexist in Fanshan complex.Geochemical analysis indicates that the ratio of Fe^(2+)/(Fe^(2+)+Mg^(2+))in biotite ranges from 0.37 to 0.69,and the total aluminum(TAl)varies from 2.594 to 3.129.Biotite compositional records show high oxygen fugacity and temperature in the magma-fluid transforming system.In addition,biotite is rich in iron which indicates the genesis of iron ore body.Integrating all results,it is demonstrated that the biotites of Fanshan phosphate deposit are characterized by high temperature,high oxygen fugacity and high volatility,which is the reason that Fe-P ore body occur in Fanshan complex.

关 键 词：矾山磷矿 流体成矿 地球化学 黑云母 

分 类 号：P595[天文地球—地球化学] P619.2[天文地球—地质学]