鹿井铀矿田庙背垅地区赋矿碱交代岩岩石学、地球化学特征  

Petrography and Geochemical Characteristics of Uranium-bearing Alkali Metasomatite in Miaobeilong Section,Lujing Uranium Ore Field

作　　者：李志鹏 夏菲[1] 党飞鹏 钟福军 LI Zhipeng;XIA Fei;DANG Feipeng;ZHONG Fujun(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang,Jiangxi 330013,China;Research Institute No.270,CNNC,Nanchang,Jiangxi 330200,China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,江西南昌330013 [2]核工业二七〇研究所,江西南昌330200

出　　处：《铀矿地质》2022年第1期46-57,共12页Uranium Geology

基　　金：国家重点研发计划项目(编号:2017YFC0602600);中国核工业地质局项目(编号:201930、202028-2);国家自然科学基金(编号:41862010、42002095、42172098);核资源与环境国家重点实验室自主基金项目(编号:2020216)联合资助。

摘　　要：庙背垅地区位于鹿井铀矿田中部,高昔铀矿床西南侧,铀矿化以碎裂蚀变岩亚型为主,赋矿围岩为印支期第二阶段中粗粒斑状黑云母(二长)花岗岩,含矿岩性有碱交代花岗(碎裂)岩、碱交代岩。近矿热液蚀变以钾长石化(碱交代)、赤铁矿化、水云母化、绿泥石化、碳酸盐化为主。岩石地球化学分析表明,赋矿围岩属S型花岗岩,可能是上地壳富铝的浅变质岩系在减压增温的条件下部分熔融的产物。含矿的碱交代花岗(碎裂)岩和碱交代岩SiO_(2)含量依次降低,K_(2)O与Fe_(2)O_(3)含量和Fe_(2)O_(3)/FeO值呈倍数增加,与其石英含量明显降低,碱交代、赤铁矿化发育相对应;高的U、Pb含量和更趋平坦的HREE配分曲线,表明碱交代作用不仅为成矿流体中铀元素的卸载沉淀创造了有利的物理化学环境,还可能活化了围岩中黑云母和副矿物里面的铀,同时铀的富集成矿可能与HREE的化学活动密切相关。这些特征是在鹿井矿田中部探寻碎裂蚀变岩亚型铀矿化的找矿标志。The Miaobeilong area is located in the middle of Lujing uranium ore field,on the southwest side of the Gaoxi uranium deposit.Uranium mineralization is dominated by altered cataclastic rock and alkaline metasomatism rock.The ore-bearing wall rock is the second stage medium-coarse porphyritic biotite(monzonite)granite of the Indosinian period,Ore-bearing lithology with alkali metasomatic granite(clastic)rock,alkaline metasomatism.Near-ore hydrothermal alteration is dominated by potash feldsparization(alkali metasomatization),hematite mineralization,hydromicaization,chloriteization,and carbonation.Rock geochemical analysis shows that the ore-bearing wall rock belongs to S-type granite,it may be the product of partial melting of the aluminum-rich shallow metamorphic rock series in the upper crust under reduced pressure and increased temperature.Mineral-bearing alkali metasomatism granite(clastic)rock and alkali metasomatism rock,the multiple of SiO_(2) content is reduced,the content of CaO,P_(2)O_(5) and Fe_(2)O_(3)/FeO increases exponentially,And high U,P content and a flatter HREE distribution curve,It showed that alkali metasomatism not only activates the U in the surrounding rock biotite and accessory minerals,but also creates a favorable physical and chemical environment for the precipitation and enrichment of U in the ore-forming fluid.Moreover,in the process of uranium mineralization,the accumulation and precipitation of U are related to the chemical activities of HREE are closely related.

关 键 词：碎裂蚀变岩型 赋矿碱交代岩 碱交代 鹿井矿田 

分 类 号：P588.15[天文地球—岩石学] P595[天文地球—地质学]