物探方法在内蒙古某银多金属矿区的应用研究

发布时间：2018-04-11 21:25

本文选题：磁法勘探 + 电法勘探　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：磁法勘探是物探方法中理论最成熟、工作效率最高、成本最低的方法之一,在找矿勘查中得到广泛的应用。其主要应用于寻找含磁性矿物的金属以及非金属矿床、勘查区域地质构造、含油气构造及煤田构造等。电法勘探应用范围也十分广泛,无论在金属与非金属的固体勘查中,还是在寻找地下水资源、油气矿藏和地热方面,都获得了成功的应用。电法勘探是以地壳中多数岩矿石之间存在的电学性质差异为基础,从而查明地下地质构造或矿产分布。针对本次研究区的含矿目标层的分布特点,展开地面氋精度磁法测量,大功率激电测量以及EH4大地电磁测深的工作,并对其测量成果做了深入的研究。(1)磁法测量成果:数据进行了化极、延拓处理、水平一阶导数、垂向二阶导数处理、确定了磁异常中心,并推测其埋深,判断了磁性体的断裂构造线,以及大致确定了磁性体的边界。磁测数据化极后做了小波多尺度分解,用谱分析方法计算了磁源体的平均深度。小波多尺度分解法与常规的场源分离(化极延拓)的方法相比,从判断磁源体的埋深角度看,小波多尺度分解法在实际生产应用方面更为快捷,更能够直接指导下步的工作安排。(2)大功率激电测量与EH4大地电磁测深成果:结合地质资料和化探资料,圈定了物探异常找矿靶区,大致查明了与硫化物有关的银多金属矿(化)体的空间分布特征。在综合分析物探资料的基础上,圈定具有一定规模的高磁局部异常13处、具有找矿意义的高阻高极化异常3处,并且推断本区的构造以北东走向的断裂为主,北西走向的断裂为次;区内浅部存在多条规模较大的岩脉;深部隐伏有中酸性岩基。利用磁法勘探与电法勘探相结合、激电测深与EH4大地电磁测深相结合的多种物探方法,在找寻磁铁矿与多金属矿方面,组合物探方法起到了相辅相成,相互印证的作用。并提出了“找矿重点地段进行大比例尺物探测量,总结本区的成矿规律,优选找矿靶位”的建议。通过钻孔验证情况,确认了综合物探方法找矿的有效性与合理性,为其它同类型地区找矿提供借鉴,具有一定现实意义。
[Abstract]:Magnetic exploration is one of the most mature methods in geophysical exploration, which has the highest efficiency and lowest cost, and has been widely used in prospecting.It is mainly used in the exploration of metallic and nonmetallic deposits containing magnetic minerals, exploration of regional geological structures, petroliferous structures and coalfield structures.The application scope of electrical exploration is also very wide. It has been successfully applied in solid exploration of metal and non-metal, groundwater resources, oil and gas deposits and geothermal resources.Electrical prospecting is based on the difference of electrical properties between most rocks and ores in the crust, thus the underground geological structure or the distribution of mineral resources can be ascertained.In view of the distribution characteristics of the ore-bearing target layer in this study area, the work of ground precision magnetic survey, high-power IP survey and EH4 magnetotelluric sounding is carried out.The measurement results are as follows: the data are processed by polarity, extension, horizontal first derivative, vertical second derivative, and the center of magnetic anomaly is determined, and its buried depth is estimated.The fracture structure line of the magnetic body and the boundary of the magnetic body are determined.The wavelet multiscale decomposition is made after the polarity of magnetic data is measured, and the mean depth of magnetic source is calculated by spectral analysis method.Compared with the conventional method of field source separation (polarization continuation), the wavelet multiscale decomposition method is more efficient in practical application from the perspective of determining the buried depth of magnetic source body.The results of high power IP survey and EH4 magnetotelluric sounding are as follows: combined with geological and geochemical data, geophysical exploration anomaly prospecting target area is delineated.The spatial distribution characteristics of silver polymetallic ore bodies related to sulphides are roughly identified.On the basis of comprehensive analysis of geophysical data, 13 high magnetic local anomalies with a certain scale and 3 high resistivity and high polarization anomalies with prospecting significance are delineated, and it is inferred that the faults in the north to east strike of the structures in this area are mainly faults.The faults in the NW strike are secondary, there are many larger veins in the shallow part of the area, and there are some intermediate-acid rock bases in the deep.With the combination of magnetic prospecting and electrical exploration, and the combination of IP sounding and EH4 magnetotelluric sounding, the combined geophysical prospecting methods play a complementary and mutually corroborating role in finding magnetite and polymetallic ore.The suggestion of "large scale geophysical survey in key ore prospecting area, summary of metallogenic law in this area and optimum dressing and prospecting target" is put forward.The validity and reasonableness of comprehensive geophysical prospecting method are confirmed by drilling verification, and it is of practical significance to provide reference for other prospecting in the same type of areas.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.2;P631

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