江西相山打鼓顶期流纹英安岩火山通道研究  

Study of Flow Direction of the Uranium-Bearing Rhyodacite in Xiangshan Ore Field

作　　者：黎广荣[1,2] 王哲[1] 郭福生[1] 吴昌志[2] 杨庆坤[1] 张万良 LI Guangrong;WANG Zhe;GUO Fusheng;WU Changzhi;YANG Qingkun;ZHANG Wanliang(Fundamental Science on Radioactive Geology and Exploration Technology Laboratory,East China University of Technology,Nanchang 330013,Jiangxi,China;State Key Laboratory for Mineral Deposits Research,Nanjing University,Nanjing 210093,Jiangsu,China;270 Research Institute of Nuclear Industry,Nanchang 330200,Jiangxi,China)

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,江西南昌330013 [2]南京大学内生金属矿床成矿机制研究国家重点实验室,江苏南京210093 [3]核工业270研究所,江西南昌330200

出　　处：《大地构造与成矿学》2018年第4期639-650,共12页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41572185;41402028;41772266)资助

摘　　要：江西省相山火山盆地是世界第三大火山岩型铀矿区,并且深部伴有Pb-Zn-Ag矿化。该矿区赋矿围岩主要是早白垩世流纹英安岩、碎斑熔岩、花岗斑岩及变质岩。随着对该地区研究的深入,矿田地质勘查取得了令人瞩目的进展,一批新矿床与矿化点在疑似火山颈的深部被发现,然而目前对相山火山盆地古火山通道的研究几乎是一片空白,如:打鼓顶期与鹅湖岭期火山通道是否有继承关系?通过测量及分析相山火山盆地流纹英安岩岩石磁化率各向异性的相关数据,结合野外流面及线理产状,试图探讨这个问题,并初步得到如下认识:(1)铁磁性矿物是流纹英安岩磁化率的主要载体;(2)虽然相山火山盆地后期脆性断裂活动发育,然而从野外岩石露头来看流纹英安岩并没有发生强变形,且磁化率各向异性度P_j小于1.1,指示脆性破裂对磁组构数据影响甚小;(3)研究区内流纹英安岩的磁面理总体上表现出较低的倾角,湖溪镇东部的流纹英安岩大多数表现出低角度或者近水平NNW-SSE方向的磁线理,湖溪镇西部的流纹英安岩则表现出NNE-SSW方向的磁线理,结合盆地内部钻孔及MT资料,指示相山火山盆地流纹英安岩火山通道应位于盆地西侧书塘附近,与碎斑熔岩火山通道可能没有直接的继承关系。The Xiangshan volcanic basin is the third-largest volcanic type uranium ore field in the world,which located in Jiangxi province,and accompanied by Pb-Zn-Ag mineralization.The host rocks are mainly the early Cretaceous rhyodacite and porphyroclastic lava.Even though many researches have been carried out on the orefield ever since the discovery of the deposit in 1960s,the location of volcanic caldera which is believed to be the pathways of ore-bearing fluids are still unclear.Through measurement and analysis of fabric in the field and magnetic fabric study on rhyodacite in the Xiangshan volcanic basin,the following conclusions can be inferred:(1)magnetite and pyrrhotine are the main carrier of the magnetic susceptibility;(2)the brittle fractures developed in the Xiangshan volcanic basin did not affect the magnetic fabric of the rhyodacite;(3)most of the rhyodacites in the eastern part of the study area exhibit low angle or nearly horizontal NNW-SSE magnetic lineation,while those in the western part show NNE-SSW direction.Therefore,the rhyodacite caldera is probably located in the western part of the Xiangshan volcanic basin,near the Shutang village.

关 键 词：磁化率各向异性 流纹英安岩 火山通道 铀矿 相山 

分 类 号：P541[天文地球—构造地质学]