构造控制下的蚀变—矿化体的形成——以冀西北崇礼中山沟金矿为例  

Vein geometry and ore shell formation controlled by structural——A case study of Zhongshangou gold deposit,Chongli,northern Hebei

作　　者：王丰翔 陈超[3] 栾卓然 吴姗姗 王云静[3] 冯云磊 张福祥 牛树银 WANG Fengxiang;CHEN Chao;LUAN Zhaoran;WU Shanshan;WANG Yunjing;FENG Yunlei;ZHANG Fuxiang;NIU Shuyin(Inner Mongolia Key Laboratory of Magmatic Mineralization and Ore-Prospecting,Geological Survey Institute of Inner Mongolia,Hohhot,010020;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing,100037;Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang,050031;Geological Exploration Technology Institute of Jiangsu Province,Nanjing,210049)

机构地区：[1]内蒙古自治区岩浆活动成矿与找矿重点实验室,内蒙古自治区地质调查院,呼和浩特010020 [2]中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室,北京100037 [3]河北省战略性关键矿产资源重点实验室,河北地质大学,石家庄050031 [4]江苏省地质勘查技术院,南京210049

出　　处：《地质论评》2022年第3期1106-1128,共23页Geological Review

基　　金：河北省自然科学基金资助项目(编号:D2019403015);河北省青年科学基金资助项目(编号:D2020403101);河北省高等学校科学技术研究项目(编号:ZD2019003);河北省“三三三人才工程”项目(编号:A202001014)的成果。

摘　　要：冀北崇礼县中山沟金矿是产出在水泉沟碱性杂岩体内的脉状矿床,受近N—S向断裂构造控制明显。矿化蚀变主要有钾化、硅化、泥质岩化和绿帘石化等。矿石主要呈脉状、细脉状和角砾状产出。根据不同蚀变的矿物组合和穿插关系,成矿阶段可分为钾化—贫硫化物、乳白色石英—硫化物阶段、强硅化—硫化物阶段和碳酸盐化阶段,金矿化主要与强硅化—硫化物阶段密切相关。通过详细的构造测量和矿床地球化学研究,钾化—贫硫化物阶段受左旋构造运动控制,可能为中温、中盐度(330~290℃;4.65%~6.88%NaCl_(eq))的含碳热液与大气降水混溶(δ^(18)O_(H_(2) O,V-SMOW):5.26‰~6.76‰;δD_(V-SMOW):-96.3‰~89.9‰)作用形成。硅化—硫化物阶段是由左旋运动向右旋伸展作用转变的结果,并发生了高角度大规模充填。由于发生大规模流体沸腾和热液混溶(δ^(18)O_(H_(2) O,V-SMOW):0.41‰~6.47‰;δD_(V-SMOW):-80.2‰~-92.9‰),在右旋张性脉形成乳白色石英—硫化物阶段,在右旋压扭性构造中形成脉型、细脉型硫化物和角砾岩性矿化,并与强硅化带伴生。成矿流体晚期阶段,碳酸盐化是最普遍的蚀变类型。稳定同位素(碳—氢—氧—硫)测试结果表明,含矿热液是高度演化的岩浆水和大气降水混溶的产物,部分碳可能源自地幔,并与岩浆作用有关;明显负δ^(34) S_(V-CDT)(-11.2‰~-24.8‰)表明成矿热液呈现高氧逸度。放射同位素(氦—铅)组成表明,成矿物质中的铅和氦可能部分源自地幔流体。因此,中山沟金矿构造—矿化—蚀变的形成可能与岩浆作用有关,为与幔枝构造有关的中温中硫热液矿床。Zhongshangou Au deposit,located in northern of Hebei province,is a vein-type mineralization and is obviously controlled by near N—S trending fault structure.It occurs in Shuiquangou alkaline complex.The mineralization alterations mainly include potassification,silicification,argillaceous lithification and epidote formation.The ore is mainly produced in vein,veinule and breccia.Baseed on vaious alteration mineral assemblages and intersecting relations,the mineralization stages can be divided into potassium—low sulfide,milky quartz—sulfide stage,high-silicification and sulfide,and carbonate stage.According to the detailed structural survey and Deposit geochemistry,the potassium—low sulfide stage is controlled by sino-lateral tectonic movement and may be of medium temperature and medium salinity(330~290℃;δ^(18)OH_(2) O:5.26‰~6.76‰;δ^(18)OH_(2) O:5.26‰~6.76‰;δD:-96.3‰~89.9‰).The silicification—sulfide stage is the result of the transition from leftlateral movement to right-lateral extension,and the high-angle large-scale filling occurs.Due to the occurrence of large-scale fluid boiling and thermal miscibility(δ^(18)OH_(2) O:0.41‰~6.47‰;δD:-80.2‰~-92.9‰),the formation of milky quartz—sulfide stage in the dextral tension veins and the formation of vein-type sulfide and breccia mineralization in the dextral compression and torsion structure,and associated with the silicification zone.In the late stage of ore-forming fluid,carbonation is the most common alteration type.The results of stable isotopes(C,H,O,S)indicate that the ore-bearing hydrothermal fluid is the product of miscibility of highly evolved magmatic water and meteoric water.Some of the carbon may originate from the mantle and is related to magmatism.The obvious negativeδ^(34) S(-11.2‰~-24.8‰)indicates that the ore-forming hydrothermal fluid presents high oxygen fugacity.The composition of radioisotopes(helium—lead)suggests that the lead and helium in ore-forming materials may be partially derived from mantle fluid

关 键 词：幔枝构造 脉型矿化 金矿床 找矿方向 动力机制 

分 类 号：P618.51[天文地球—矿床学]