西藏冈底斯成矿带矽卡岩矿床钴赋存状态及富集特征OA北大核心CSTPCD

As an important strategic key metal,cobalt will become increasingly vital with the rapid development of new energy,new materials and aerospace technology.Cobalt often appears in skarn deposits as an associated resource that,in some skarn deposits,can reach a large scale.Cobalt in skarn deposits is an important source of cobalt resources in China.There are many skarn deposits in the Gangdese metallogenic belt,Tibet.However,research on the enrichment characteristics and occurrence states of cobalt is lacking.In this paper,the Jiama,Longmala,Chunzhe,Zhibula,Mengyaa,Nuri,Bangpu,Pusangguo and Yaguila skarn deposits in the eastern Gangdese,and the Bangbule and Chagele skarn deposits in the western Gangdese were investigated.The enrichment characteristics and occurrence states of cobalt in representative ores in the deposit were studied by means of hand-held X-ray fluorescence analyzer,optical electron microscopy observation,scanning electron microscopy observation and electron probe microanalysis.The results of hand-held X-ray fluorescence analysis show that the deposits in the eastern Gangdese are enriched with cobalt to varying degrees.The average cobalt contents of Jiama,Zhibula,Pusangguo and Chunzhe deposits are 853×10-6,410×10-6,460×10-6 and 898×10-6 respectively,while the cobalt contents of Bangbule and Chagele deposits in the western Gangdese is lower than the detection limit(＜3×10-6).The results of optical electron microscopy observation,scanning electron microscopy observation and electron probe microanalysis show that cobalt mainly exists in the form of cobaltite in the Jiama deposit,cobaltite and carrollite in the Pusangguo deposit,siegenite in the Zhibula deposit.Other skarn deposits in the eastern Gangdese are mostly distributed in the form of isomorphism in pyrite,bornite,chalcopyrite,sphalerite,tetrahedrite,tellurite,rather than independent minerals.Based on all the above experimental results and analyses,the enrichment degree of cobalt in the skarn deposits in the eastern Gangdese is distinctly higher than that in the western Gangdese,indicating that the former has better cobalt enrichment potential than the latter.The cobalt enrichment characteristics of skarns deposits in the eastern Gangdese would be controlled by the deep lithosphere structure.These characteristics may be related to the partial melting of juvenile lower crust in the eastern Gangdese,and the mineralization does not exclude the mixing of atmospheric precipitation.The main purpose of this research is to develop an understanding of cobalt enrichment characteristics and metallogenic mechanism,which can provide reference for subsequent exploration works.