纳米比亚罗辛地区矿化白岗岩铀矿物学研究及意义  

Uranium mineralogical research and significance of mineralized alaskite in Rossing area,Namibia

作　　者：陈旭 范洪海 何德宝[1,2] 陈金勇 耿瑞瑞[1,2] 陈东欢 王勇剑 CHEN Xu;FAN Honghai;HE Debao;CHEN Jinyong;GENG Ruirui;CHEN Donghuan;WANG Yongjian(Beijing Research Institute of Uranium Geology,Beijing,100029;Key Laboratory of Uranium Resource Exploration and Evaluation Technology,CNNC,Beijing,100029)

机构地区：[1]核工业北京地质研究院,北京100029 [2]中核集团铀资源勘查与评价技术重点实验室,北京100029

出　　处：《地质论评》2024年第3期907-923,共17页Geological Review

基　　金：中核集团自主研发项目--罗辛铀矿及外围资源扩大研究;国家自然科学基金资助项目(编号:42302094);东华理工大学联合创新基金资助项目(编号:NRE2021-04)的成果。

摘　　要：罗辛矿床为世界级白岗岩型铀矿床,存在SJ、SH、SK、Z17、Z19等多个矿(化)带,各矿(化)带矿物组合存在较大差异,但系统的矿物学研究程度不高。本次工作通过岩矿鉴定、扫描电镜观察、电子探针分析等方法,系统研究罗辛地区主要矿(化)带铀矿物共生组合及赋存状态。结果显示,白岗岩矿化按矿物组合可划分为3类:①晶质铀矿+锆石+磷灰石组合,主要分布在Z17、Z19、SJ矿床(带);②铀石、铀钍石+榍石+磷灰石组合,主要分布在SH矿床;③贝塔石组合,主要分布在SK、SH矿床。研究区铀成矿可划分为3个期次:岩浆期、热液期、表生淋积期。岩浆期为主成矿期,研究区晶质铀矿电子探针化学年龄为505±11 Ma,代表岩浆期成矿年龄。SH应进一步寻找铀石、铀钍石+榍石+磷灰石组合矿化白岗岩。Objectives:The Rossing deposit is a world-class alaskite-type uranium deposit,with multiple mineralization zones such as SJ,SH,SK,Z17,and Z19.There are significant differences in mineral combinations among these zones,but the level of systematic mineralogical research is not high.Methods:This work systematically studied the symbiotic combination and occurrence status of uranium minerals in the main ore(mineralization)zones of the Rossing area through methods such as rock—mineral determination,scanning electron microscopy observation,and electron probe analysis.Results:The results show that the mineralization of alaskite mineralization can be divided into three categories based on mineral assemblages:①uraninite+zircon+apatite combination,mainly distributed in the Z17,Z19,and SJ areas;②coffinite,uranothorite+sphene+apatite combination,mainly found in the SH area;③betafite combination,mainly distributed in the SK and SH areas.Conclusions:The uranium mineralization in the study area can be divided into three stages:magmatic stage,hydrothermal stage,and epigenetic leaching stage.The magmatic stage is the primary ore-forming stage,the electron probe chemical age of uraninite in the study area is 505±11 Ma,representing the magmatic mineralization age.In the SH area,further exploration should focus on finding coffinite,uranothorite+sphene+apatite combination in mineralized alaskite.

关 键 词：矿物组合 多期成矿 白岗岩型铀矿床 纳米比亚罗辛地区 

分 类 号：P619.14[天文地球—矿床学]