综合物探方法在五里营地区火山岩型铀矿勘查中的应用

摘要

Volcanic rock type uranium deposits could be generated in volcanic rock body and also from shallow metamorphic rock and volcanic rock mass near the lower Palaeozoic strata in the Mesozoic continental glutenite,so the detection of the development situation of related volcanic rock body is of great significance for the further development of uranium exploration work.This paper briefly introduces the controlled source audio-frequency magnetotelluric (CSAMT) measurement and the work method of high precision magnetic survey and ground in the five camps in practical application.Combined with the geological data and petrophysical characteristics,the authors used CSAMT survey data,found out the general andesitic porphyrite and thick deep development characteristics of the porphyry,and made use of the ground high-precision magnetic survey data,thus improving the recognition reliability of the contact zone of rock mass and fracture structure inference.Drilling verification shows that the effect is good.Comprehensive analysis shows that CSAMT survey has better vertical resolution,and can accurately detect the deep development of rock mass characteristics,the location of the fracture development and the deep situation;the contoured ground high-precision magnetic survey can roughly delineate rock mass,and identify the contact zone of rock mass as well as the fracture.The two methods together can more comprehensively solve geological problems and provide effective technical means for volcanic type uranium deposit exploration.%火山岩型铀矿床既可以产于火山岩体内,也产于火山岩体附近下古生界浅变质岩和中生界陆相砂砾岩中,因此火山岩体发育情况的探测对铀矿勘查工作的进一步开展具有重要意义.笔者简要介绍了可控源音频大地电磁测量(CSAMT)和地面高精度磁测的工作方法以及在五里营地区的实际应用.结合地质资料和岩石物性特征,利用CSAMT测量资料,大致查明了安山玢岩和粗安斑岩的深部发育特征,利用地面高精度磁测资料提高了识别岩体接触带及断裂构造推测的可靠性.通过钻孔验证,效果较好.综合分析认为:CSAMT测量有较好的垂向分辨力,能够较准确得探测岩体的深部发育特征、断裂发育的位置及向深部延伸情况,地面高精度磁测可大致圈定岩体,识别岩体接触带、断裂等;两种方法相互结合可以较为全面的解决地质问题,为火山型铀矿勘查提供有效技术手段.