白云鄂博REE-Nb-Fe矿床地球化学特征及其地质意义  

Element geochemical characteristics of granite in the Bayan Obo REE-Nb-Fe areas:implications for its geological

作　　者：丁志刚 漆剑 DING Zhi-gang;QI Jian(The Sixth Geological Brigade of Jiangxi Geological Bureau,Yingtan Jianxi,335001)

机构地区：[1]江西省地质局第六地质大队,江西鹰潭335001

出　　处：《世界有色金属》2022年第6期104-107,共4页World Nonferrous Metals

摘　　要：白云鄂博REE-Nb-Fe矿床是世界上目前已知的最大稀土矿床,关于白云鄂博矿床的成因问题一直存在争议。由于花岗岩和矿体距离相近,并且花岗岩和白云岩接触部位形成的矽卡岩有部分稀土矿化,因此曾有人主张稀土成矿是由花岗岩引起的。我们对本区花岗岩中的粗粒花岗岩进行了主微量元素分析,结果表明粗粒花岗岩成分接近石英二长岩,具有富硅的特点。粗粒花岗岩的铝饱和指数及里特曼指数δ表明其为准铝质、钙碱性岩石。根据花岗岩类型判别图解,我们研究的花岗岩属于钙碱性系列。根据花岗岩岩石系列判别图,表明研究的粗粒花岗岩属于A-型花岗岩。由花岗岩与富矿白云质大理岩稀土元素特征相差巨大,并且成矿年龄明显老于花岗岩侵入年龄,因此可推断花岗岩的侵入与稀土元素的成矿作用并无直接联系。Bayan Obo REE-Nb-Fe deposit is the world's largest known rare earth deposit,the genesis of the Bayan Obo deposit has long been controversial.Because of the close spatial relationship between granite and ore body,and skarn that form in the contact zone between granite and dolomite had some rare earth mineralization,that is why it was considered that the rare earth mineralization is caused by the granite magmatism.Here we studied the geochemical characteristics of coarse-grained granite in this area.Result of major elements show that coarse-grained granite has composition close to quartz monzonite,and has the characteristics of silicon-rich.Aluminum saturation index and Rittman indexδof coarsegrained granite indicate its aluminum,calc-alkaline rocks.According to the granite type discrimination diagrams,our samples belong to calc-alkaline with alkali-rich granite.According granite rock series discrimination diagrams,our granite samples show that they belong to A-type granite.The REE characteristics of granite are very different from and the ore bearing dolomite marble,as well as mineralization occurred significantly older than the age of granitic intrusions,therefore,the granite magmatism is not directly caused REE mineralization in the Bayan Obo.

关 键 词：白云鄂博 成矿年龄 A-型花岗岩 

分 类 号：TG146.454[一般工业技术—材料科学与工程]