辽宁五龙地区中生代火成岩成因及其找矿意义  

Petrogenesis of Mesozoic igneous rocks and its prospecting significance in Wulong area, Liaoning Province

作　　者：李德东[1] 王玉往[1] 邱海成 李建平 张凤琴[3] 杜佰松 解洪晶[1] 张志超 LI Dedong;WANG Yuwang;QIU Haicheng;LI Jianping;ZHANG Fengqin;DU Baisong;XIE Hongjing;ZHANG Zhichao(Beijing Institute of Geology for Mineral Resources Co.,Ltd.,Beijing,100012;Wulong Gold Mine Co.,Ltd.,Dandong,Liaoning,118008;China University of Geosciences(Beijing),Beijing,100083)

机构地区：[1]北京矿产地质研究院有限责任公司,北京100012 [2]辽宁五龙黄金矿业有限公司,辽宁丹东118008 [3]中国地质大学(北京),北京100083

出　　处：《地质论评》2022年第4期1439-1463,共25页Geological Review

基　　金：国家重点研发计划项目(编号:2018YFC0603804)的成果。

摘　　要：辽宁五龙金矿是辽东地区大型岩浆热液型矿床之一,成矿作用主要与中生代火成岩有关,为了进一步理清五龙地区中生代火成岩成因,笔者等对五龙金矿区大量花岗斑岩脉、闪长岩脉、三股流岩体和其中的各类脉岩进行了单颗粒锆石LA-ICPMS U-Pb测年和岩石主、微量元素地球化学研究。结果表明,五龙地区岩浆岩形成时代主要有晚侏罗世和早白垩世,矿区内近南北向展布的花岗斑岩脉形成于晚侏罗世(154.3±0.9~155.6±1.1 Ma),指示矿区在晚侏罗世受到区域最大主应力方向为近南北向;三股流岩体成岩最新年龄(116.8±0.8~117.3±0.7 Ma)基本位于前人报道的年龄范围(111~129 Ma);地球化学数据表明各类岩浆岩属于高钾钙碱性—钾玄岩系列,具有相同源区特征,形成于活动大陆边缘俯冲伸展环境下的弧岩浆,并且具有壳幔混合及进一步演化特征;结合不同深度标高成矿元素丰度特征,指示闪长岩与成矿作用密切相关,并且越往深部成矿潜力越大,对该地区找矿预测具有重要指导意义。Objectives:The Wulong gold deposit is one of the large magmatic hydrothermal deposits in Liaodong(eastern Liaoning)area,and its mineralization is mainly related to Mesozoic igneous rocks.In order to clarify the causes of Mesozoic igneous rocks in Wulong area,the geochemical analysis of numerous granite porphyry dykes,diorite dykes,Sanguliu pluton and zircon chronology were tested.Methods:The LA-ICPMS U-Pb dating test and analysis work was performed on the single-particle zircons.The major elements were performed by the XRF method,and trace elements were performed by ICP-MS method.Results:The chronologic results show that there are two diagenetic eras in Wulong area,i.e.the Late Jurassic and the Early Cretaceous.The near north—south trending granitic porphyry dykes in the deposit formed in the Late Jurassic(154.3±0.9~155.6±1.1 Ma),indicating that the maximum principal stress direction is near north—south in the Late Jurassic,and latest diagenetic age(116.8±0.8~117.3±0.7 Ma)of the Sanguliu intrusion rocks basically lies in the age range reported by predecessors,showing that the Sanguliu intrusion experienced a long time.Geochemistry results indicate that the magmas belonged to high-K calcium alkaline and shoshonite series are from the same arc magmatic source,and they form in subduction and extension environment in the active continental margin with the crust—mantle mixing characteristics and further evolution trend.Conclusions:Combined with ore-forming elements of different depth level indicate that the diorite is closely related to mineralization,and the deeper the metallogenic potential is greater,which has important guiding significance for prospecting prediction in the region.

关 键 词：LA-ICPMS锆石年代学 岩石地球化学 岩浆作用 辽东五龙金矿 三股流岩体 

分 类 号：P618.51[天文地球—矿床学] P534.5[天文地球—地质学] P588.1