临沧花岗岩带三叠纪花岗岩地球化学特征与三稀金属成矿  

Geochemical Characteristics of Triassic Granites in Lincang Granite Belt and Mineralization of Rare Earth,Rare Metal and Rare-scattered Elements

作　　者：曾凯 Zeng Kai(Hubei Institute of Metallurgical Geology (Central South Institute of Metallurgical Geology),Yichang,Hubei 443003)

机构地区：[1]湖北冶金地质研究所(中南冶金地质研究所),湖北宜昌443003

出　　处：《资源环境与工程》2020年第S02期1-7,66,共8页Resources Environment & Engineering

基　　金：中国地质调查局项目“滇西地区三稀等重要矿产地质调查”(编号:DD20179604)资助。

摘　　要：临沧花岗岩带地处滇西三江地区,呈近南北向展布,主体岩性为三叠纪黑云母二长花岗岩,花岗岩风化壳发育。为深入认识临沧花岗岩与三稀金属成矿的内在联系,对带内三叠纪黑云母二长花岗岩及其风化壳开展岩石学、地球化学等方面的研究,以典型矿床为例,总结三稀金属成矿特征与三叠纪花岗岩的关系。经地质勘查,三叠纪黑云母二长花岗岩具有富硅、富碱、铝过饱和的特点,富集大离子亲石元素、轻稀土元素,稀土配分型式为右倾平缓的浅“V”型,为(风化壳)离子吸附型稀土矿成矿母岩。中北段局部地区三叠纪花岗岩稀散元素丰度较高,为褐煤型稀散金属矿蚀源母岩。三稀金属成矿海拔高,特别是稀土矿,一般在1000 m以上富集成矿,并具有南(富)多北(贫)少、西贫东富、轻稀土相对富集的特点。Lincang granite belt is located in the Sanjiang area of Western Yunnan,which is distributed in a nearly north-south direction.The main lithology is Triassic biotite monzogranite,and the weathering crust of granite is developed.In order to deeply understand the internal relationship between the Lincang granite and the mineralization of rare earth,rare metaland rare-scattered elements,the petrology and geochemistry of the Triassic biotite monzogranite and its weathering crust are studied.Taking typical deposits as an example,the relationship between the mineralization characteristics of rare earth,rare metaland rare-scattered elements and Triassic granite is summarized.After geological exploration,the Triassic biotite monzogranite is rich in silicon,alkali and aluminum supersaturation.It is rich in large ion lithophile elements and light rare earth elements.The REE distribution pattern is shallow“V”type with gentle right dip,and the Triassic biotite monzogranite is the parent rock of ion adsorption type rare earth ore.The Triassic Granites in some parts of the north central section are rich in scattered elements,which are the source rocks of lignite type scattered metal deposits.The ore-forming altitude of rare earth,rare metaland rare-scattered elements is high,especially the rare-earth ores,which are generally enriched and mineralized over 1000 m,with the characteristics of“more(rich)in the South and less(poor)in the North,poor in the West and rich in the East,and relatively rich in light rare earth”.

关 键 词：临沧花岗岩带 三叠纪黑云母二长花岗岩 风化壳 三稀金属成矿 地球化学特征 

分 类 号：P588.12+1[天文地球—岩石学] P595[天文地球—地质学]