首页|江西甘坊洞上稀有金属花岗岩中铷矿化特征及成因机制

江西甘坊洞上稀有金属花岗岩中铷矿化特征及成因机制

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江西省宜丰县甘坊地区是一个重要的稀有金属成矿区,目前在甘坊岩体内发现了一系列锂铷稀有多金属矿床(点),但其成矿机制尚不明确.选择甘坊岩体内洞上花岗岩作为研究对象,采用电子探针技术对多种花岗岩中的长石和云母类矿物进行了精细的结构和成分分析.结果表明,云母类矿物是铷的主要载体(Rb2O<1.07%),长石类矿物中Rb含量低(Rb2O<0.11%),尤其是在钠长石中Rb的含量几乎为 0.含铷云母主要是白云母花岗岩、伟晶岩和细晶岩中的多硅白云母-铁锂云母类,其中铷可能主要通过与钠双置换云母结构中的层间钾离子存在.矿物结构特征显示,洞上花岗岩经历了明显的岩浆结晶分异和流体交代作用.结晶分异作用可能是洞上花岗岩Rb富集成矿的关键机制,而后期流体交代蚀变过程对铷的聚集作用有限.结合前人研究成果,笔者认为甘坊地区具有较好的锂、铷等稀有金属成矿潜力,后续的找矿勘查应注重与早白垩世—晚侏罗世(140~150 Ma)高分异花岗岩相关的锂、铷等稀有金属矿床的找矿工作.
Genesis of Rb mineralization of the Dongshang rare metal granite in Jiangxi Province
The Ganfang district in the Yifeng County,Jiangxi Province is an important rare metalmetallogenic area.A series of Li-Rb rare metal deposits(mineralization)have been discovered in the Ganfang intrusions,while the mineralization mechanism of rare metals is not clear yet.The detailed mineralogy texture and composition of feldspars and micas from the Dongshang granite have been analyzed by electron microprobe analysis.The results show that micas are the main carriers of Rb(Rb2O<1.07%),and the contents of Rb in feldspars are lower(Rb2O<0.11%),particularly in albite.The Rb-bearing micas are mainly phengite to zinnwaldite from muscovite granite,pegmatite,and granitic aplite.The substituted mechanism of Rb in micas is mainly coupled with Na for interlayer cation of K.The mineral textures record both magma crystallization differentiation and fluid metasomatism for the Dongshang granites,however,the former was the key mechanism of the Rb enrichment,while the later has less role on the accumulation of Rb in granites.Together with previous publications,this paper concluded that the Ganfang intrusions have a good metallogenic potential of rare metals,and the subsequent prospecting should focus on the Li,Rb,and other rare metals related to the Early Cretaceous to Late Jurassic(140~150 Ma)highly differentiated granites.

rare metalsgraniteRbDongshang graniteGanfang intrusionsJiangxi Provincemineral exploration engineering

姜军胜、郭欣然、徐净、田立明、熊光强、王力圆、陈素余、黄维坤

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中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉 430205

中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉 430205

广东省地质科普教育馆,广东广州 510000

福州大学紫金地质与矿业学院,福建福州 350108

江西省地质矿产勘查开发局物化探大队,江西南昌 330000

福建冶地恒元建设有限公司,福建福州 350108

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稀有金属 花岗岩 洞上花岗岩 甘坊岩体 江西 矿产勘查工程

中国地质调查局花岗岩成岩成矿地质研究中心开放基金南京大学内生金属矿床成矿机制研究国家重点实验室开放研究基金中国地质调查局项目

PMGR2020042021-LAMD-K07DD20230576

2024

地质通报
中国地质调查局

地质通报

CSTPCD北大核心
影响因子:1.226
ISSN:1671-2552
年,卷(期):2024.43(1)
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