辽东半岛五龙金矿成矿系统新认识:来自外围热液角砾岩型铅锌矿化的指示  

New sight for gold forming system in Wulong deposit:Indicated by the distal Pb-Znmineralization in hydrothermal breccia

作　　者：姚晓峰[1] 颜廷杰[1] 林成贵 李生辉 宓奎峰 李建平 李阳[4] 杜宛鸽 YAO XiaoFeng;YAN TingJie;LIN ChengGui;LI ShengHui;MI KuiFeng;LI JianPing;LI Yang;DU WanGe(Development and Research Centre,China Geological Survey,Mineral Exploration Technical Guidance Center,Ministry of Natural Resources,Beijing 100037,China;103 Brigade of Non-ferrous Geological Bureau of Liaoning Province,Dandong 118008,China;Liaoning Wulong Gold Mining Corporation Limited,Dandong 118000,China;China University of Geosciences,Beijing 100083,China;Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]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,北京100037 [2]辽宁有色地质局103队,丹东118008 [3]辽宁五龙黄金公司,丹东118000 [4]中国地质大学(北京),北京100083 [5]成都理工大学,成都610059

出　　处：《岩石学报》2021年第6期1883-1900,共18页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2018YFC0603806);中国地质调查局二级项目(DD20190166);国家自然科学基金项目(41902101)联合资助。

摘　　要：五龙金矿是辽东半岛形成于早白垩世的代表性石英脉型金矿。本文报道了在五龙矿区边部新发现的热液角砾岩型铅锌矿化及其密切相关的闪长岩的特征,这对进一步认识五龙成矿系统提供了新的指示。热液角砾岩属于岩浆热液爆破角砾岩,铅锌矿化分布在角砾岩石英胶结物和石英脉内。角砾岩下伏和旁侧的闪长岩内可见梳状结构和晶洞结构,也可见蚀变和矿化发育,指示闪长岩与角砾岩具有密切的成因联系。角砾岩的石英胶结物和含矿石英脉的δ^(18)O_(H2O)在-2.7‰~0.1‰之间、δD_(V-SMOW)在-71.5‰~-85.9‰之间,指示矿化流体为岩浆水和大气降水混合成因,与五龙金矿晚阶段成矿流体性质基本相同。闪长岩的锆石U-Pb测年指示其结晶年龄为120.9±1.3Ma,与五龙金矿成矿时代近于一致。闪长岩与五龙成矿系统具有密切的时间、空间和成因联系,可以作为"桥梁"连接岩浆作用和成矿作用。闪长岩属于高钾钙碱性系列,具有轻稀土富集、无铕异常的稀土配分模式,以及富集大离子亲石元素(Rb、Ba)而亏损高场强元素(Nb、Zr、Hf)的微量元素特征,其(^(87)Sr/^(86)Sr)t值在0.711~0.712之间、εHf(t)值在-8.2~-9.0之间、εHf(t)值在-21.2~-22.8之间,推测其主要为富集岩石圈地幔部分熔融的产物,认为富含相容元素的幔源岩浆源区是金成矿的重要物质基础。五龙矿床石英脉型金矿与热液角砾岩型铅锌矿化属于同一岩浆热液系统的不同位置的表现样式,预测整个成矿系统深部可能发育有赋存于岩体(株)内外接触带的席状石英脉型矿化和浸染状矿化。Wulong deposit is a typical quartz vein-type gold deposit formed in the Early Cretaceous in Liaodong Peninsula.We reported characteristics of a newly found Pb-Zn mineralization spot in hydrothermal breccia and it’s closely associated with a diorite dike in the distal area of Wulong gold deposit,and it may be helpful for further understanding the ore-forming system in the area.The breccia was probably formed in a process of hydrothermal explosive fracturing.Galena and sphalerite occurred in the quartz cement or quartz veins.Miarolitic cavities,comb quartz layers,mineralization and alteration can be found in the diorite below or by the breccia,which can indicate the Pb-Zn mineralization are genetically associated with the diorite.Theδ^(18)O_(H2O)andδD_(V-SMOW)values of quartz from the cement and veins are-2.7‰-0.1‰and-7.5‰~-85.9‰,which support a mixture of magmatic and meteoric fluids,the same as the late hydrothermal stage fluids in Wulong gold deposit.Moreover,U-Pb dating of the zircons from the diorite yield 206Pb/238U mean age of 120.9±1.3 Ma,which was nearly coeval with Wulong deposit.The diorite shows closely spatial,temporal,and geochemical relationships with Wulong ore-forming system,and it can be taken as a"bridge"to connect magmatism and mineralization.The diorite belongs to the high-K calc-alkaline series,with enrichment in light rare earth elements and large-ion lithophile elements,and depletion in high-field-strength elements.The(87 Sr/86 Sr)t,εNd(t),andεHf(t)values of measured samples from the diorite are 0.711~0.712,-8.2~-9.0 and-21.2~-22.8,respectively.It can be inferred that the diorite is mainly originated from enriched lithospheric mantle which are enriched in compatible elements and provided materials for the Au mineralization.The quartz-vein type gold lode in Wulong and the distal Pb-Zn mineralization area belong to an ore-forming system related to intrusion,and it can be predicted that sheeted ore-hosting veins and disseminated mineralization lie in the contact zone of deep-seat

关 键 词：华北克拉通 辽东 五龙金矿 热液角砾岩 岩浆热液金成矿系统 

分 类 号：P597.3[天文地球—地球化学] P618.51[天文地球—地质学]