赣南珠坑钨矿赋矿花岗岩独居石年龄、地球化学特征及成因探究  

Monazite U-Pb age,geochemistry,and genesis of ore-bearing granites in the Zhukeng tungsten deposit,southern Jiangxi Province

作　　者：高原 王颖[3,4] 王海 徐喆 张勇 周渝[1,2,3] 张芳荣 孙超 贺彬 张思远 张福神 GAO Yuan;WANG Ying;WANG Hai;XU Zhe;ZHANG Yong;ZHOU Yu;ZHANG Fangrong;SUN Chao;HE Bin;ZHANG Siyuan;ZHANG Fushen(Institute of Basic Geological Survey,Jiangxi Geological Survey and Exploration Institute,Nanchang 330030,Jiangxi,China;Jiangxi Province Key Laboratory of Exploration and Development of Critical Mineral Resources,Nanchang 330009,Jiangxi,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,Jiangxi,China;Institute of Geomechanics,China Academy of Geological Sciences,Beijing 10081,China)

机构地区：[1]江西省地质调查勘查院基础地质调查所,江西南昌330030 [2]关键矿产资源勘查与开发江西省重点实验室,江西南昌330009 [3]核资源与环境国家重点实验室(东华理工大学),江西南昌330013 [4]中国地质科学院地质力学研究所,北京10081

出　　处：《地质力学学报》2025年第2期325-339,共15页Journal of Geomechanics

基　　金：东华理工大学核资源与环境国家重点实验室开放基金项目(2022NRE09);江西省关键矿产资源勘查与开发重点实验室开放基金(GHKC2024KF08);放射性地质与勘探技术国防重点学科实验室开放基金(2022RGET08);国家自然科学基金项目(42062006);江西省自然科学基金项目(20232BAB213065);江西省地质局科技研究项目(2022JXDZKJKY02);江西省“科技+地质”联合计划项目(2023KDG01003);江西省地质局青年科学技术带头人培养计划项目(2022JXDZKJRC04)。

摘　　要：珠坑岩体为赣南地区与钨矿和铌钽矿密切相关的由二云母花岗岩-白云母花岗岩构成的复式岩体。通过对赣南广昌县珠坑钨矿赋矿岩体白云母花岗岩、二云母花岗岩开展系统的岩石地球化学分析和成岩时代研究,结合区域成岩成矿研究结果,探讨岩体成因和构造背景。LA-ICP-M_(S)分析结果显示,细粒白云母花岗岩中的独居石^(206)Pb/^(238)U加权平均年龄为156.7±1.3 Ma,主量元素具有典型的富硅(SiO_(2)含量为65.54%~74.95%)、富碱(Na_(2)O+K_(2)O含量为8.48%~12.85%)、高铝(A/CNK介于1.10~1.22)和贫Mg特征,稀土元素总量(ΣREE)介于61.12×10^(-6)~173.98×10^(-6),显示弱富集轻稀土,稀土元素配分曲线呈弱右倾,具有明显的负铕异常,Rb、Ta、Th、Pb、Nd、Hf富集,Ba、Nb、Sr和Ti亏损,属于高分异S型花岗岩;二云母花岗岩中的独居石^(206)Pb/^(238)U加权平均年龄为159.5±0.9 Ma,主量元素具有典型的富硅(SiO_(2)含量在75.02%~77.03%)、富碱(Na_(2)O+K_(2)O含量为5.92%~8.58%)、高铝(A/CNK=1.14~1.65)和贫Mg特征,稀土总量ΣREE介于106.86×10^(-6)~124.24×10^(-6),显示轻稀土富集,稀土配分曲线呈右倾斜,具有明显负铕异常;Rb、Ta、Th、Pb、Nd、Hf富集,Ba、Nb、Sr和Ti亏损,属于高分异S型花岗岩。综合年代学和岩石地球化学特征,珠坑钨矿花岗岩侵位时代为晚侏罗世,为俯冲背景下大规模花岗质岩浆活动作用产物。[Objective]The composite Zhukeng granite is composed of two-mica granite and muscovite granite and closely related to tungsten and niobium-tantalum deposits in southern Jiangxi Province.[Methods]Based on systematic lithogeochemical analysis and rock-forming age determination of muscovite granite and two-mica granite from the Zhukeng tungsten deposit,combined with regional studies concerning diagenesis and mineralization,the genesis and tectonic setting of the rock mass are discussed.[Result]The LA-ICP-M_(S)analysis of monazite from the fine-grained muscovite granite yielded a ^(206)Pb/^(238)U weighted average U-Pb age of 156.7±1.3 Ma.Major elements exhibit high silica contents(SiO_(2) ranging from 65.54%to 74.95%),high alkalis contents(Na_(2)O+K_(2)O ranging from 8.48%to 12.85%),high aluminum contents(A/CNK ratios ranging from1.10 to 1.22),and low magnesium contents.The total rare earth elements(ΣREE)range from 61.12×10^(-6) to 173.98×10^(-6),and there are right-dipping light rare earth enrichment patterns with a weak negative Eu anomalies.The trace elements Rb,Ta,Th,Pb,Nd,and Hf are enriched,while Ba,Nb,Sr,and Ti are depleted,indicating a highly differentiated S-type granite.The LA-ICP-M_(S)analysis of monazite U-Pb from the two-mica granite yielded an ^(206)Pb/^(238)U weighted average age of 159.5±0.5 Ma.Major elements exhibit high silica contents(SiO_(2) ranging from 75.02%to 77.03%),high alkalis contents(Na_(2)O+K_(2)O ranging from 5.92%to 8.58%),high aluminum contents(A/CNK ranging from 1.14 to 1.65),and low magnesium contents.Total rare earth elements(ΣREE)range from 106.86×10^(-6) to 124.24×10^(-6),and there are right-dipping light rare earth enrichment patterns with a significant negative Eu anomalies.The trace elements Rb,Ta,Th,Pb,Nd,and Hf are enriched,while Ba,Nb,Sr,and Ti are depleted,suggesting a highly differentiated S-type granite.[Conclusion]By combining geochronological and lithogeochemical characteristics,the authors conclude that the Zhukeng tungsten deposit formed during an Upper Juras

关 键 词：赣南 珠坑岩体 花岗岩型钨矿 独居石U-Pb定年 地球化学 

分 类 号：P584[天文地球—岩石学] P597[天文地球—地质学]