若尔盖铀矿床中硅质灰岩岩石学及地球化学  

Petrology and Geochemistry of Siliceous Limestone in Uranium Deposits in the Roigê Region

作　　者：王永飞[1] 李宝新[1] 陈田华[1] 张新民[1] 董之凯 WANG Yong-fei;LI Bao-xin;CHEN Tianhua;ZHANG Xinmin;DONG Zhikai(Sichuan Institute of Uranium Geological Survey,Chengdu 610061)

机构地区：[1]四川省核工业地质调查院,成都610061

出　　处：《四川地质学报》2018年第2期225-230,244,共7页Acta Geologica Sichuan

基　　金：四川省国土资源厅"四川省若尔盖县拉尔玛铀矿普查(川国土资函[2017]107号)"地勘基金项目资助

摘　　要：若尔盖地区志留系内产出的众多铀矿床中含有层状、似层状、透镜状硅质灰岩,对其成因的研究有助于查明矿床成因和确定区域找矿方向。研究表明,硅质灰岩化学成分不稳定,以碱性CaO或酸性SiO_2为主。据硅质灰岩中蚀变矿物的微量元素地球化学特征,认为其流体主要来源于深部。从硅质灰岩的稀土配分看出,Ce/Ce*和Eu/Eu*值适中,硅质灰岩是海底喷流沉积的产物。硅质灰岩的δ^(13)C值偏高,具海洋沉积碳酸盐岩的碳同位素组成特征。在铀矿床中δ^(18)O值较高,表现为地幔来源的特点。U的矿化程度与Al_2O_3-MnO-Fe_2O_3含量呈正相关,与P_2O_5呈负相关,与SiO_2-CaO-K_2O-TiO_2-Na_2O-MgO组合呈显著负相关。Many uranium deposits in the Zoigê region occur in Silurian which contains stratified, stratoid and lenticular siliceous limestone. Study of origin of the siliceous limestone is a great help to determination of regional range of reconnaissance. The study indicates that the siliceous limestone is production of submarine sedimentary exhalative process and characterized by medium Ce/Ce＊ and Eu/Eu＊ values, higher δ^（18） O and δ^（13） C values, showing mantle-derived features. The uranium mineralization has a positive correlation with Al2O3-Mn O-Fe2O3 content and a negative correlation with P2O5 and SiO2-CaO-K2O-TiO2-Na2O-MgO association.

关 键 词：铀矿床 岩石学 地球化学 硅质灰岩 若尔盖 

分 类 号：P619.14[天文地球—矿床学] P584[天文地球—地质学]