北山地区石炭纪海相火山岩中基鲁纳型铁矿床的厘定及对区域成矿的指示:以内蒙古碧玉山铁矿床为例  

Newly identified iron oxide-apatite deposit in Carboniferous marine vol-canic rocks in the Beishan area and its implications for regional metalloge-ny:A case study of the Biyushan iron deposit,Inner Mongolia

作　　者：胡浩[1] 殷勇 徐磊 HU Hao;YIN Yong;XU Lei(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Wuhan),Wuhan 430078,China;Geological Survey of Gansu Province,Lanzhou 730000,China)

机构地区：[1]中国地质大学(武汉)地质过程与矿产资源国家重点实验室,武汉430078 [2]甘肃省地质调查院,兰州730000

出　　处：《地质科技通报》2024年第4期219-223,共5页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42272089)。

摘　　要：北山地区发育众多赋存于石炭纪海相火山岩中的铁矿床,其中内蒙古碧玉山铁矿床是该区典型的这类矿床之一。该矿床地处内蒙古自治区的西北缘,勘查工作程度相对较低,矿床成因研究程度较为薄弱。经过野外及初步的岩相学观察工作对内蒙古碧玉山铁矿床进行了研究。研究表明,碧玉山铁矿床普遍具有磁铁矿-磷灰石的矿物组合,其中磷灰石普遍经历溶解-再沉淀作用而导致内部含有大量细小的独居石包裹体。磁铁矿中普遍发育钛铁矿出溶结构,具有高温的磁铁矿特征。这些特征与区域上发育的具有矽卡岩化及低钛磁铁矿的其他矿床明显不同,而与典型的基鲁纳型(铁氧化物-磷灰石型)铁矿床在矿物组合及磷灰石、磁铁矿矿物学特征等方面非常相似。笔者对该铁矿的地质特征开展初步分析认为,内蒙古北山地区碧玉山铁矿床属于赋存于海相火山岩中的基鲁纳型铁矿床,这对该区基鲁纳型铁矿床的成矿理论及找矿勘查工作具有指导意义。[Objective]Numerous iron deposits hosted in Carboniferous marine volcanic rocks occurred in the Beishan Orogenic Belt,Eastern Tianshan.The Biyushan iron deposit,located at the northwestern margin of Inner Mongolia,is a typical iron deposit hosted in Carboniferous marine volcanic rocks.[Methods]In this study,we utilized field observation,microscope imaging,and scanning electron microscopy to charaterize the mineral assemblages of iron ores and microtextures of magnetite and apatite,in order to decipher the genesis of iron ores.[Results]Our preliminary work has revealed that iron ores in the Biyushan deposit commonly have a mineral assemblage of magnetite-apatite,with apatite having abundant monazite inclusions due to the dissolution-reprecipitation processes.In addition,magnetite grains commonly have high Ti contents with ilmenite exsolution.Thus,the mineral assemblage of iron ores and mineralogical features of apatite and magnetite are similar to these of typical Kiruna-type deposits.[Conclusion]Based on our preliminary analysis of geological characteristics,we suggest that the Biyushan iron deposit in Inner Mongolia is likely a Kiruna-type iron deposit hosted in submarine volcanic rocks that has not yet been documented.Therefore,these findings can guide future exploration of iron oxide-apatite deposits in this region.

关 键 词：基鲁纳型(铁氧化物-磷灰石型)矿床 碧玉山铁矿 磁铁矿 磷灰石 矿床成因 

分 类 号：P618.31[天文地球—矿床学]