综合电磁法在矿区深部成矿机制中的应用研究——以皖南乌溪多金属矿区为例

发布时间：2018-03-01 00:19

本文关键词： 成矿机制综合电磁法乌溪多金属矿斑岩　出处：《地球物理学报》2016年11期 　论文类型：期刊论文

【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.
[Abstract]:The Wuxi mining area is a new prospecting area in the south of the Yangtze Orogen between the polymetallic metallogenic belt and the South China metallogenic belt in the middle and lower reaches of the Yangtze River. In this paper, an effective electromagnetic comprehensive exploration has been carried out in this new ore prospecting area. We collected the geological and geochemical data, analyzed the regional metallogenic background from the geological and geochemical data, and collected the main rock types of the regional outcrop. On the basis of the physical property measurement in the laboratory, three kinds of electromagnetic methods were selected to carry out field survey in the study area. Three geophysical methods, namely, ground high precision magnetic measurement, excitation polarization method and controllable source audio magnetotelluric method (CSAMT), were adopted. The distribution characteristics of magnetic susceptibility, polarizability and resistivity in the study area are studied. The relationship between geological, geochemical and geophysical data and mineralization is analyzed, and the metallogenic model is discussed. On the basis of geophysical research results and geological and geochemical background data, the metallogenic dynamics model of the study area is constructed. The metallogenic mechanism of the study area is inferred, and the metallogenic potential of the ore area is revealed. The combined results are drilled, and the drilling results reveal the existence of strong mineralization alteration and strong altered porphyry in the deep part of the study area, which are preliminarily confirmed as porphyry type deposits. The results are consistent with the interpretation of CSAMT profile and the mechanism of deep mineralization in the predicted area. The results of borehole drilling and geophysical results are consistent with those of the established metallogenic dynamic model. It fully proves the important role of comprehensive electromagnetic method in the discovery and prediction of porphyry polymetallic deposits, and the confirmation of porphyry deposits further confirms the similarity between the metallogenic belt of South China and the metallogenic belt formed by subduction. So as to promote the whole South China metallogenic geological research.
【作者单位】：中国科学院地质与地球物理研究所;中国科学院大学;中国科学技术大学地球和空间科学学院;
【分类号】：P631.325;P618.2

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