EH4连续电导率成像仪在隐伏矿体定位预测中的应用研究  

Application of stratagem EH4 system to prediction of hidden ore bodies

作　　者：申萍[1] 沈远超[1] 刘铁兵[1] 李光明[1] 秦克章[1] 曾庆栋[1] 

机构地区：[1]中国科学院矿产资源研究重点实验室中国科学院地质与地球物理研究所,北京100029

出　　处：《矿床地质》2007年第1期70-78,共9页Mineral Deposits

基　　金：中国科学院创新工程项目(KZC3-SW-137);国家科技攻关"305"项目(2001BA609A-07-08和2003BA612A-06-19)的联合资助

摘　　要：EH4连续电导率成像仪是近几年美国生产的快速高效的数字化地球物理探测仪器，其基本配置（10～100kHz）的装置能测量地表以下1000m深度范围内地质体的连续视电导率值，作者对25个不同类型的金属矿床进行了隐伏矿定位预测，取得了显著的效果。经钻孔验证后显示：①岩浆熔离型铜镍硫化物矿床，很好地反映了基性-超基性杂岩体的形态和规模，并识别了岩体的不同岩相，得出矿化异常岩相呈盆状，电阻率为130～300Ω·m的结论；②斑岩型-浅成低温铜金矿床，区分了隐伏斑岩和矿化蚀变带，确认矿化异常在隐伏斑岩外围呈面状分布，矿化异常体的电阻率小于100Ω·m；③韧性剪切带型金矿床，明显区分了矿化蚀变构造带和围岩，矿化异常形态呈脉状，电阻率小于200Ω·m。这3个矿床实例研究表明，EH4连续电导率成像仪测量所得的二维视电阻率-深度剖面图能清晰地反映地下不同地质体的精细电阻率结构，判读含矿构造带以及矿化异常在空间上的展布，因此，EH4连续电导率成像仪在隐伏矿定位预测方面将起到重要的作用。The Stratagem EH4 system, made by Geometries ＆ EMI Electromagnetic magnetotelluric system using both natural and man-made electromagnetic signals Instruments, Inc., is a unique to obtain a continuous electrical sounding of the earth beneath the measurement site. It can be utilized to measure the electrical conductivity of the earth over the depth range from a few meters to more than one kilometer by 10 Hz-100 kHz. The authors have applied the Stratagem EH4 system to the exploration of various types of metallic deposits in China in search for new resources since 2001, with good results acquired. The results obtained can be displayed by a 2D model map （resistivity-depth map）. The 2D model map can clearly identify fine resistivity structures of different resistivity bodies. The EH-4 inversion tested by drilling has yielded some new results： ①the shape and size of the studied mafic-ultrarnafic intrusion are displayed, and different intrusion facies and magma channels are identified. This intrusion is 800 m wide and up to 450 m deep, assuming a funnel-shaped cross-section. The smaller resistivity （130-300Ω·m） for the magmatic liquation Cu- Ni deposit, corresponding to mineralized altered lithofacies, shows a basin in section; ②a concealed porphyry with high resistivity （higher than 300Ω·m） is detected. What is most important is that the mineralization anomaly resulting from the epithermal copper-gold deposits may be defined by the smaller resistivity （lower than 100 Ω·m）, with the anomaly assuming planar distribution; ③the concealed gold ore body of the shear type gold deposit can be detected by the resistivity value of lower than 200 Ω·m, with its shape being veinlike in section. The resistivity value of the wall rock is higher than 360 Ω ·m. The three examples of the studied deposits show that the electrical conductivity imaging of EH4 data can not only clearly identify different resistivity anomalies but also reflect the shape and size of the buried mineralized body or the

关 键 词：地球物理 EH4连续电导率成像仪 矿化异常 隐伏矿体 铜镍矿床 斑岩铜矿 金矿床 

分 类 号：P618.53[天文地球—矿床学]