粤北铀矿控矿断裂活动年代学特征与找矿规律——以南雄断裂带为例  

Chronological Characteristics and Prospecting Regularity of Ore-controlling Fault Activities in UraniumMines in Northern Guangdong Province:Take the Nanxiong Fault Belt as an Example

作　　者：赵佳楠 刘冲昊 邱际玮 苏宏亮 崔永春 曾凡杰 ZHAO Jianan;LIU Chonghao;QIU Jiwei;SU Hongliang;CUI Yongchun;ZENG Fanjie(Guangdong Province Nuclear Industry Geological Bureau 291 Brigade,Guangzhou 510800,China;Guangdong Geological Bureau,Guangzhou 510080,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]广东省核工业地质局二九一大队,广东广州510800 [2]广东省地质局,广东广州510080 [3]中国地质科学院矿产资源研究所,北京100037

出　　处：《金属矿山》2024年第3期158-171,共14页Metal Mine

基　　金：中国地质调查局发展研究中心(自然资源部矿产勘查技术指导中心)基金项目(编号:121201004000150017-65,121201004000160901-77,121201004000172201-61,DD20190159-10)。

摘　　要：为研究粤北地区铀矿控矿断裂活动特征和控矿规律以指导找矿,以南雄盆地北缘南雄断裂带为研究对象,通过野外地质剖面调查、LA-ICP-MS锆石U-Pb年代学研究和显微构造变形分析,讨论南雄断裂带活动特征和铀矿找矿规律。研究结果表明:南雄盆地北缘南雄断裂带在三叠纪的构造变形特征以韧性变形为主,岩浆期后热液石英脉和长英质脉于晚三叠世交切断裂带内花岗质糜棱岩和糜棱岩化花岗岩,脉体锆石U-Pb加权平均年龄分别为(230.2±1.7)Ma、(228.9±5.8)Ma和(210.0±2.1)Ma;断裂带内发育典型韧性变形显微构造特征,韧性变形运动特征以左行剪切为主,且具有高温变形和中低温变形2个阶段。认为南雄盆地北缘南雄断裂带内210 Ma韧性变形区段不具备铀矿质沉淀的临界转换成矿机理条件,推断125~120 Ma和110~105 Ma韧性变形强烈并叠加同期区域伸展运动、基性岩脉侵入和铀矿化特征的区段可能是铀成矿有利区段。分析结果为进一步提高诸广山南部整装勘查区铀资源量提供了可行的找矿思路和有效的铀矿查证区段。In order to study the characteristics of ore-controlling fault activities and ore-controlling laws in uranium mines to guide mineral exploration in northern Guangdong Province,the Nanxiong Fault Belt in the northern Margin of the Nanxiong Basin is taken as the research object,and the characteristics of the Nanxiong Fault Belt activities and the prospecting regularity of uranium mines have been discussed through researches on field geological sections,LA-ICP-MS zircon U-Pb chronology and characteristics of microstructural deformation.The research results show that the features on tectonic deformation of the Nanx-iong Fault Belt in Triassic are mainly ductile deformation,and the post-magmatic hydrothermal quartz veins and felsic dikes in the Late Triassic cut through granitic mylonite and mylonite granite.Their weighted average ages of zircon U-Pb isotopic analy-sis are respectively(230.2±1.7)Ma,(228.9±5.8)Ma and(210.0±2.1)Ma.The microstructural characteristics of granitic mylonite and mylonite granite in the Nanxiong Fault Belt have show typical ductile deformation phenomenons with"S-C"fab-ric,elongation and dynamic recrystallization of quartz,"σ"type rotational fragmentation of quartz and book oblique structure of plagioclase feldspar.These characteristics of microstructural movement mainly present left-row shear in the direction of ductile deformation.In Triassic,two stages of elevated-temperature deformation and medium-low temperature deformation have been re-vealed.It is considered that these areas of 210 Ma ductile deformation in Nanxiong Fault Belt do not have the conditions of ore-forming mechanism of critical transformation for precipitation of uranium mines.These is a inferential conclusion that the areas,in which the granites experienced strong ductile deformation in 125~120 Ma and 110~105 Ma,regional extensional movement of the same period and had been accompanied by intrusion of mafic dykes and uranium mineralization,can become metallogenic prospective areas of uranium mineralization or depositing

关 键 词：铀矿 南雄断裂带 韧性变形 电子背散射衍射 锆石U-PB年代学 找矿规律 

分 类 号：P613[天文地球—矿床学] P619.14[天文地球—地质学]