桃坑铀矿床红盆中赤铁矿地球化学特征及其对成矿流体的指示  

Geochemical Characterization of Hematite in the Red Basin of Taokeng Uranium Deposit and Its Implications for Mineralizing Fluids

作　　者：苏伟政 邓腾 许德如 孙会饶 董昕昱 陈欣 SU Weizheng;DENG Teng;XU Deru;SUN Huirao;DONG Xinyu;CHEN Xin(School of Earth Sciences,East China University of Technology,Nanchang,Jiangxi 330013,China;National Key Laboratory Uranium Resource Exploration-Mining and Nuclear Remote Sensing,Nanchang,Jiangxi 330013,China;Research Institute No.270,CNNC,Nanchang,Jiangxi 330200,China)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]铀资源探采与核遥感全国重点实验室,江西南昌330013 [3]核工业二七〇研究所,江西南昌330200

出　　处：《铀矿地质》2025年第2期292-313,共22页Uranium Geology

基　　金：地学核技术四川省重点实验室开放基金项目(编号:gnzds202304);放射性地质与勘探技术国防重点学科实验室开放基金项目(编号:2022RGET12);中国核工业地质局项目(编号:2023-31-9)联合资助。

摘　　要：桃坑铀矿床位于桃山—诸广铀成矿带兴国铀矿化集中区,是该地区重要的铀矿床之一。桃坑铀矿床矿化发育于花岗岩岩体中,同时也在白垩系红盆中发育,前人对该矿床进行了初步的研究,但其成矿流体特征及成矿机制尚不清晰。赤铁矿是发育于热液型铀矿床中常见矿物,与铀成矿具有密切的关系。文章以桃坑铀矿床赤铁矿为研究对象,通过开展岩相学和地球化学特征研究,讨论赤铁矿成因及其对成矿流体性质的指示意义,为揭示矿床成因和下一步找矿勘探提供理论依据。岩相学研究表明,桃坑铀矿床赤铁矿形态多样,其中沉积成因的赤铁矿呈粒状、肾状,热液成因的赤铁矿形貌受裂隙或交代其他矿物影响,呈微晶状、板状、多孔状、细脉状、面状、球状,与铀成矿关系密切的赤铁矿主要呈脉状和面状;主、微量元素分析显示,桃坑铀矿床赤铁矿整体呈现微富集轻稀土元素,贫重稀土元素的配分模式,具有Ce、Eu负异常,表明成矿流体是由大气降水和深部热液混合形成;赤铁矿中P含量相对较高,且Th/La值大于1,说明赤铁矿形成时流体具有富F和P特点,并随着水-岩反应的进行,流体向偏碱性演化。Taokeng uranium deposit is situated in Xingguo uranium mineralization cluster of the Taoshan-Zhuguang uranium metallogenic belt.Uranium mineralization are found in granite and Cretaceous red basin formations.Preliminary studies have been conducted on this deposit,but the characteristics of ore-forming fluid and ore-forming mechanism are still unclear.In hydrothermal uranium deposit,hematite is found widely distributed and closely associated with uranium mineralization.In this paper,we focus on the hematite from the Taokeng uranium deposit,examining its petrographic and geochemical characteristics.We discussed the genesis of hematite and its implications for the properties of ore-forming fluids,providing a theoretical basis for understanding the deposit's formation and guiding future prospecting and exploration efforts.The characteristics of main element and in situ trace element of the hematite indicate that hematite in Taokeng uranium deposit appears in various form are predominantly of hydrothermal origin.Its morphology is influenced by fractures and metasomatic interactions with other minerals.The formation of hematite in Taokeng deposit was characterized by the mixing of atmospheric precipitation and deep hydrothermal fluid,the fluid was rich in fluoride F and P,and evolved towards an alkaline state as water-rock interactions progress.

关 键 词：赤铁矿成因 地球化学特征 成矿流体 矿床成因 桃坑铀矿床 

分 类 号：P619.14[天文地球—矿床学]