地质学报2025，Vol.99Issue(4)：1256-1273,中插31-中插32,20.DOI:10.19762/j.cnki.dizhixuebao.2023083
桂北摩天岭地区达亮和新村富铀矿床矿物学特征及对矿床成因的指示意义
Mineralogical studies of ore and gangue minerals in Daliang and Xincun deposits of Motiangling ore district,northern Guangxi,South China:Implications for ore genesis
摘要
Abstract
To further elucidate the multi-stage uranium metallogenic mechanism of the Motianling area in northern Guangxi,we studied the characteristics of mineralization and alteration,uranium occurrences and the mineralogical geochemistry of pitchblende,pyrite,and chlorite in two typical uranium deposits(Daliang and Xincun)using optical microscopy,scanning electron microscopy(SEM),and electron microprobe analysis(EMPA).The results show that the uranium minerals in the uranium-chlorite(pyrite)type ores from the Daliang deposit are mainly composed of uraninite,brannerite,and a minor amount of phosphoric uraninite.In contrast,the uranium occurrence of the Xincun deposit is relatively simple,dominated by uraninite with minor coffinite.Geochemical analysis shows that the uraninite from the Daliang deposit is relatively enriched in Pb and REEs,while the associated pyrite shows elevated As content.In comparison,the uraninite from the Xinchun deposit is enriched in W and Ca.These geochemical signatures suggest that the two types of uranium mineralization in the Motianling area formed in a medium-to low-temperature environment,with the granite itself or adjacent strata potentially providing abundant ore material for the formation of uranium mineralization.Based on the chlorite geothermometer,the mineralization temperature of the Daliang ore deposit is estimated to be 218～243℃,consistent with homogenization temperatures obtained from fluid inclusions,further supporting a medium-to low-temperature environment.Pre-ore chlorite in the Xincun deposit formed at temperatures ranging from 219～243℃,significantly higher than the mineralization-stage homogenization temperature of fluid inclusions.The formation mechanisms of chlorite include dissolution-crystallization and dissolution-migration-crystallization processes.关键词
铀赋存状态/矿物组合/沥青铀矿/绿泥石/摩天岭地区/广西Key words
uranium occurrence/mineral assemblage/uraninite/chlorite/Motianling area/Guangxi引用本文复制引用
王勇剑,庞雅庆,范洪海,吴玉,章健,杨航,麻乾坤..桂北摩天岭地区达亮和新村富铀矿床矿物学特征及对矿床成因的指示意义[J].地质学报,2025,99(4):1256-1273,中插31-中插32,20.基金项目
本文为国家自然科学基金项目(编号42302094)、广西省地矿局地质科研项目(编号桂地矿核2024-15)、中国核工业地质局地勘费科研项目(编号202238-10)和核工业北京地质研究院院长青年基金项目(编号地QJ2101)联合资助的成果. （编号42302094）
