新疆西天山智博铁矿床磁铁矿成分对其成矿机制的指示  

Magnetite composition of Zhibo iron deposit in western Tianshan mountains of Xinjiang and its mineralization mechanism significance

作　　者：武阳 申萍[1,2,3] 潘鸿迪 李昌昊[1,2,3] 冯浩轩[1,2,3] 李文广 谢日实 WU Yang;SHEN Ping;PAN HongDi;LI ChangHao;FENG HaoXuan;LI WenGuang;XIE RiShi(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Science,University of Chinese Academy of Sciences,Beijing 100049,China;Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China;College of EarthSciences,Chang’an University,Xi’an 710054,Shaanxi,China;No.3 Geological Party,Xinjiang Bureauof Geology and Mineral Resources,Korla 841000,Xinjiang,China)

机构地区：[1]中国科学院矿产资源研究重点实验室,中国科学院地质与地球物理研究所,北京100029 [2]中国科学院大学地球与行星科学学院,北京100049 [3]中国科学院地球科学研究院,北京100029 [4]长安大学地质科学与资源学院,陕西西安710054 [5]新疆维吾尔自治区地质矿产勘查开发局第三地质大队,新疆库尔勒841000

出　　处：《矿床地质》2021年第3期539-554,共16页Mineral Deposits

基　　金：国家重点研发计划项目(编号:2018YFC0604004)资助。

摘　　要：智博铁矿床位于新疆西天山阿吾拉勒成矿带东段,主要赋矿围岩为石炭系大哈拉军山组安山岩、玄武质安山岩和火山碎屑岩。该矿床主要有东、中、西3个矿区,其中以东矿区为主矿区。矿体主要呈层状、似层状、厚板状和透镜状。金属矿物以磁铁矿为主,含有少量黄铁矿、赤铁矿和黄铜矿。矿石构造以块状和浸染状构造为主,此外还有角砾状构造、条带状构造、流纹状构造和脉状构造等。矿石结构有他形-半自形结构、板条状结构和海绵陨铁结构等。智博铁矿床蚀变矿物主要有透辉石、钠长石、阳起石、绿帘石、钾长石等,含有少量方解石、石英和绿泥石等。根据矿石和矿物共生关系,将智博铁矿床划分为岩浆期和热液期2个成矿期次。岩浆期可划分为钠长石-透辉石阶段和磁铁矿-阳起石阶段,热液期可划分为钾长石-绿帘石阶段和石英-硫化物阶段。根据智博磁铁矿的电子探针数据,各类磁铁矿矿石中除热液期含黄铁矿致密块状矿石w(FeO_(T))变化较大外,其他类型磁铁矿的w(FeO_(T))多集中在90%~95%,又以岩浆期块状矿石中w(FeO_(T))最高。对其氧化物进行相应的图解,电子探针数据中w(CaO)、w(Al_(2)O_(3))、w(MnO)、w(K_(2)O)、w(MgO)和w(SiO_(2))都和w(FeO_(T))有良好的负相关性,而NiO和TiO_(2)则具有一定的正相关性,V_(2)O_(3)则在岩浆期块状和含磁铁矿脉矿石中含量明显高于其他类型矿石。根据磁铁矿TiO_(2)-Al_(2)O_(3)-MgO成因图解和w(Ca+Al+Mn)-w(Ti+V)成因图解显示,智博铁矿床矿石兼具岩浆型成因特征和热液型成因特征,表明智博铁矿床的形成与岩浆作用和火山热液交代作用有关。Located in the eastern section of the eastern Awulale metallogenic belt in the Western Tianshan Mountains,the Zhibo iron ore deposit is hosted in andesite,basaltic andesite and pyroclastic rocks of the Lower Carboniferous Dahalajunshan Formation.The western,middle and eastern ore districts make up the Zhibo iron deposit,among which the eastern ore district is the main ore district,in which the orebodies occur in layered,plate-like or lenticular forms.In addition to the magnetite as the mainly metallic mineral,there exists a little pyrite,hematite and chalcopyrite.The ore structure can be divided mainly into six types,i.e.,massive,disseminated,brecciform,banded,striated and vein ores,of which massive and disseminated ores are in the majority,meanwhile,the ore textures include anhedral-subhedral,plate and sideronitic forms.The altered minerals in the Zhibo iron deposit mainly include diopside,albite,actinote,epidote and potassium feldspar,with a small amount of calcite,quartz and chlorite.According to the association relationship between ores and minerals,the Zhibo iron deposit can be divided into two metallogenic periods,namely magmatic period and hydrothermal period.There are sodium feld‐spar-diopside stage and magnetite-actinote stage of the magmatic period,while K-feldspar-epidote stage and quartz-sulfide stage comprise the hydrothermal period.Based on the electron microprobe analyses of Zhibo mag‐netite,it is shown that,except for the late pyrite containing massive block ore(FeO_(T)),the other kinds of magnetite ores have the concentration of FeO_(T) of other types of magnetite ores in the range of 90%~95%,with the early mas‐sive ore(FeO_(T))being the highest.In the light of the corresponding diagram of its oxides,all the data on the whole show that the values of CaO,Al_(2)O_(3),MnO,K_(2)O,MgO and SiO_(2) have a good negative correlation with FeO_(T),while NiO and TiO_(2) show the opposite,and it is obvious that the values of V_(2)O_(3) in the initial block and magnetite-bea-ring vein ores are significan

关 键 词：地球化学 磁铁矿 电子探针 智博铁矿床 

分 类 号：P618.31[天文地球—矿床学]