摘要
乌溪矿区介于长江中下游多金属成矿带与华南成矿带之间,是江南造山带上的一个找矿新区.本文在这一找矿新区开展了有效的电磁方法综合勘探,试图对该区深部成矿机制进行研究.我们收集了该区的地质地球化学资料,从地质地球化学资料中分析了区域成矿背景;我们还采集了区域出露的主要岩石类型,在实验室开展物性测定,在此基础上选择了三种电磁方法开展研究区的野外测量.通过地面高精度磁测、激发极化法和可控源音频大地电磁法(CSAMT)三种地球物理方法,开展了研究区的磁化率、极化率和电阻率的分布特征研究.深入分析了地质、地球化学和地球物理三种资料与成矿的关系,相互约束,探讨成矿模型、成矿机制和成矿的可能性,推测可能的矿体赋存位置和深度范围.在地球物理研究结果基础上,结合地质和地球化学背景资料,构建了研究区的成矿动力学模型,推测了研究区成矿机制,揭示了矿区的成矿潜力.综合所得结果布设了钻孔,钻探结果揭示了研究区深部存在强烈矿化蚀变和强蚀变斑岩,初步确认为斑岩型矿床,与CSAMT剖面的解释结果基本一致,也与推测的测区内深部成矿机制相吻合.钻孔结果和地球物理结果的一致性以及对已构建的成矿动力学模型的支持,充分证明了综合电磁方法在斑岩型多金属矿床的发现和预测中的重要作用,同时斑岩型矿床的确认进一步印证了华南成矿带与俯冲作用形成的成矿带的相似性,从而推动整个华南地区的成矿地质研究.
The Wuxi polymetallic ore deposit which lies between the middle and lower reaches of the Yangtze River polymetallic metallogenic belt and South China metallogenic belt,is a newprospecting area in the Jiangnan orogen.This article is trying to study the mineralization mechanism in the deep subsurface of this area with the effective electromagnetic integrated exploration.For a new prospecting area,the collection of regional geological and geophysical background is very important.Geological data in this area is collected,which permits to analyze the regional metallogenic background.The physical property of the main rock types exposed in this area is measured in the laboratory.On the basis of these results three electromagnetic field measurements are carried out.By the measurements of three kinds of geophysical methods：ground precise magnetic survey,induced polarization and controlled source audio magnetotelluric method（CSAMT）,the distribution characteristics of magnetic susceptibility,polarization and resistivity are studied,to bound mineralization possibilities and possible ore body position and depth range together.Based on the results of the geophysical studies,combined with geological and geochemical data,the mineralization dynamics model of the study area is built and then the mineralization mechanism is suggested.Drillings are deployed according to all these results.Drilling results prove the presence of strong alteration,mineralization and porphyry alteration at depth in the study area,which is consistent with the judgment of the CSAMT results.The consistency of drilling and geophysical results fully demonstrate the important role of the integrated electromagnetic method in the discovery and prediction of porphyry type polymetallic deposits.Meanwhile,it confirms the similarity between South China metallogenic belt and the mineralization belt formed by the subduction,thus promoting mineralization geological studies throughout South China.
作者
林方丽
王光杰
杨晓勇
LIN Fang-Li WANG Guang-Jie YANG Xiao-Yong(Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China University of Chinese Academy of Sciences, Beijing 100049, China School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230036, China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2016年第11期4323-4337,共15页
Chinese Journal of Geophysics
关键词
成矿机制
综合电磁法
乌溪多金属矿
斑岩
Metallogenic Mechanism
Integrated Approach of Electric Magnetic Method
Wuxi Polymetallic Ore
Porphyry
