吉林省延边地区造山型金矿地球物理特征及找矿方向研究——以海沟金矿为例  

Geophysical Characteristics and Prospecting Direction of Orogenic Gold Deposits in Yanbian Area,Jilin Province:Taking Haigou Gold Deposit as an Example

作　　者：许志河[1] 李福文[1] 孙念仁 王迺宸 牛军平 苏永飞 XU Zhihe;LI Fuwen;SUN Nianren;WANG Naichen;NIU Junping;SU Yongfei(Jilin Exploration Geophysics Institute,Changchun 130000,Jilin,China;Jilin Geological Exploration Fund Management Center,Changchun 130000,Jilin,China)

机构地区：[1]吉林省勘查地球物理研究院,吉林长春130000 [2]吉林省地质勘查基金管理中心,吉林长春130000

出　　处：《西北地质》2020年第3期184-190,共7页Northwestern Geology

基　　金：吉林省地质勘查基金管理中心“吉林省长白山玄武岩覆盖区及周边矿产资源调查”(22201300102)。

摘　　要：夹皮沟海沟金城洞构造岩浆(杂岩)带为吉林省重要的金成矿区带,海沟金矿位于该构造岩浆(杂岩)带的中部,其经过古生代和中生代多期岩浆平行贯入与早晚不同性质断裂(韧性与脆性)以及不同样式构造(环形、弧形与线性)的叠加混合,这些地质事件与金矿成矿关系极其复杂。同时,海沟金矿深部成矿预测也已成为当务之急。笔者试图通过地球物理方法,如磁法、重力、可控源音频大地电磁法剖面分析对应分析海沟金矿表层浅部、中部以及深部地球物理场异常特征。由于海沟金矿表层及浅成控矿构造为韧脆性构造转换部位和脆性构造,中层控矿构造指受绿片岩相韧性剪切带控矿,深层控矿构造主要为受角闪岩相韧性剪切。因此,不同深度地球物理场特征是控制金矿鉴别标志。磁低缓正异常中局部高异常尖峰定位层及浅成控矿构造,重力正负异常梯度带定位中层成控矿构造,陡峭低阻异常带定位深部控矿构造。由深至浅的控矿构造反映出大陆张裂、隆滑和拆离构造等多种大陆壳动力学机制转变过程中的地球物理场特征的变化。最后通过对比典型金矿带地球物理特征,对深部及外围是否存在该类型金矿床进行预测。Jiapigou-Haigou-Jinchengdong tectonic-magmatic(complex)belt is an important gold metallogenic belt in Jilin Province.Haigou gold deposit is located in the middle of this tectonic-magmatic(complex)belt.It underwent the superimposition of multi-period of magma parallel penetration in Paleozoic and Mesozoic,fracture of different properties(toughness and brittleness)in different time and different types of structures(ring,arc mixed with linear).These geological events have extremely complex relationship with gold mineralization.deep metallogenic prediction of Haigou gold deposit has become a top priority.In this paper,such geophysical methods as magnetic method,gravity method and magnetotelluric method of controllable source audio-frequency are used to analyze the geophysical anomalies of surface-shallow,middle and deep parts of Haigou gold deposit.The surface and shallow ore-controlling structures of Haigou gold deposit are ductile-brittle structural transition and brittle structures.The middle ore-controlling structures are controlled by the ductile shear zone of greenschist facies.And the deep ore-controlling structures are mainly controlled by the ductile shear of amphibolite facies.Therefore,the geophysical field characteristics of different depths are the distinguishing indicators of controlling gold deposits.In the magnetic low-gentle positive anomaly,the localized high anomaly spike location layer and shallow ore-controlling structure,the gravity positive and negative anomaly gradient zone locates the middle ore-controlling structure.And the steep low-resistivity anomaly zone locates the deep ore-controlling structure.The deep-to-shallow ore-controlling structures reflect the changes of geophysical field characteristics in the transformation of the dynamic mechanism of continental crust,such as continental tension,uplift-slip and detachment structures.by comparing the geophysical characteristics of typical gold ore belts,whether or not there is this type of gold deposits in the deep and periphery is predicted

关 键 词：吉林省延边地区 海沟金矿 石英脉型金矿 成矿预测 地球物理勘探 

分 类 号：P618.51[天文地球—矿床学]