湘东北白沙窝稀有金属矿床电性特征与找矿预测研究  

Electrical characteristics and metallogenic prediction of Baishawo rare metal deposit in northeast Hunan Province

作　　者：柳建新[1,2] 曹丽 郭振威[1,2] 曹创华[2,3] 陈旭 LIU Jianxin;CAO Li;GUO Zhenwei;CAO Chuanghua;CHEN Xu(School of Geosciences and Info-Physics,Central South University,Changsha 410083,Hunan,China;Key Laboratory of Non-Ferrous Resources and Geological Hazard Detection,Central South University,Changsha 410083,Hunan,China;Geology Survey Institute of Hunan Province,Changsha 410016,Hunan,China)

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083 [2]中南大学有色资源与地质灾害探查湖南省重点实验室,湖南长沙410083 [3]湖南省地质调查所,湖南长沙410016

出　　处：《地质力学学报》2024年第5期768-780,共13页Journal of Geomechanics

基　　金：国家自然科学基金项目(42130810);湖南省自然科学基金项目(2023JJ60164,2023JJ60166);湖南省地质院科研项目(HNGS202201);湖南省地质院领军人才科研项目(HNGSTP202318)。

摘　　要：花岗伟晶岩型稀有金属矿床是最重要的稀有金属矿床类型之一。连云山东部新发现了白沙窝伟晶岩型矿床,初步评估白沙窝矿床深部稀有金属资源潜力巨大,但该矿床的矿产开采程度很低,围绕深部隐伏花岗伟晶岩脉的研究程度不高。通过研究白沙窝伟晶岩型矿床的深部电性结构特征,探讨稀有金属成矿模型及赋矿载体的空间分布,阐明矿脉就位关系,旨为稀有金属找矿预测提供依据。通过可控源音频大地电磁法(CSAMT)在白沙窝岩体东南方向开展深部隐伏岩(矿)体的探测工作,采用共轭梯度法反演实测3条探测剖面数据,探测深部隐伏岩(矿)体,并结合钻孔信息和元素地球化学异常特征信息进行综合分析,揭示隐伏岩脉的分布及成矿特征。研究结果表明,隐伏伟晶岩脉主要位于冷家溪群中,集中分布在花岗岩体顶部及构造裂隙周围,埋深在50~300 m;伟晶岩脉的成矿地球物理标志为深部高阻体侵入浅部低阻体中的高阻脉状地质体。研究成果为白沙窝矿床后续勘查工作提供了科学依据,揭示了伟晶岩脉的形成机理,并为湘东北及华南地区的稀有金属勘查提供了可靠的物探预测技术和经验。[Objective]The aim of this study is to characterize the deep electrical structure of the Baishawo pegmatite-type deposits,explore the spatial distribution of rare metal mineralization models and ore-conferring carriers,and elucidate the relationship between the location of ore veins to provide a basis for prediction in rare metal mineral exploration.[Methods]Through the controlled-source audio-geomagnetic method(CSAMT)and the conjugate gradient method of inverse measurement of three exploration profiles,deep hidden rock(ore)bodies were detected.Then,by combining these results with the information from drill holes and elemental geochemical anomalies,a comprehensive analysis was carried out to reveal the distribution of the hidden dikes and the mineralization characteristics.[Results]The study showed that the concealed pegmatite veins are mainly located in the Lengjiaxi Group,where they are concentrated on the top of the granite body and around tectonic fissures and have burial depths ranging from 50 to 300 m.The geophysical signature of pegmatite vein mineralization is a high-resistance vein-like geologic body intruded from a deep high-resistance body into a shallow low-resistance body.[Conclusion]The determined distribution and burial depth of concealed pegmatite veins,identified potential concealed veins in the study area,and geophysical characteristics of the pegmatite vein mineralization provide a basis for understanding the formation mechanism of fracture zone-constrained pegmatite veins.Significance The research results provide a scientific basis for follow-up exploration of the Baishawo deposit,reveal the formation mechanism of the pegmatite veins,and provide reliable physical exploration and prediction technology and experience useful for rare metal exploration in northeast Hunan and south China.

关 键 词：伟晶岩 连云山 CSAMT 锂-铍-铌-钽矿床 稀有金属 

分 类 号：P631.34[天文地球—地质矿产勘探]