摘要
根据白云鄂博赋矿白云石大理岩的岩石学特征及地质产状将其分为两类：粗粒和细粒白云石大理岩．它们的氧、碳和锶同位素及微量元素地球化学特征显然有别于分布在宽沟背斜以北典型的沉积石灰岩和白云岩，而和幢源火成碳酸岩十分相似．与矿床进行对比研究说明，成矿流体和矿质主要起源于碳酸岩浆的分异作用，其放射性成因同位素和微量元素保持了地但指纹，而氧和碳同位素组成却向壳源方向漂移，证实碳酸岩浆侵位过程中受大陆地壳的混染作用非常微弱，但是由碳酸岩浆活动所引起的成矿热液体系中却有一定的地表水混人认为白云鄂博REE—Nb—Fe超大型矿床的成因应归属于火成碳酸岩型矿床．
The host rocks of the giant Bayan Obo REE-Nb-Fe ore deposit, Inner Mongolia, could be divided into coarse-grained dolomite marble(HS.) and fine-grained dolomite marble(H8f)based on their texture and occurrence. They have distinctive differences of O, C and Sr isotope composition and trace element patterns from those of HS. that shows very weak metamorphism and deformation and is distributed to the north of the Kuangou fault zone,occurring together with quartz Sandstone, sandstone and shale which compose the Bayan Obo group of the middle Proterzoic age with normal sedimentsry origin, but are similar to carbonatites. Compared with the ore deposit, it could deduced that mineralizing fluids and materials are derived from defferentiaton of carbonatite magma, which remain the mantle signature for radioactive genetic isotopes and trace elements, while O and C isotopes shift toward to the crust reource. although these evidence confirm that carbonatite magma is rarely effected by the crust contamination during intrusion through the upper crust, the mineralizing fluids associated with carbonatite magma would be added by a mount of meteoric water. The genesis of the giant Bayan Obo REE-Nb-Fe ore deposit is sUggested to be a carbonatite one.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第S1期216-227,共12页
Chinese Journal of Geophysics
基金
中国科学院留学经费择优支持回国工作基金
中国科学技术大学科学基金
关键词
碳酸岩
壳-幔相互作用
矿床成因
稳定同位素
Carbonatite, Crust-mantle interaction, Genesis of ore deposit, Bayan Obo.
