CSAMT和浅层地震在松辽盆地西南部铀矿勘查中的应用

Application of CSAMT and Shallow Seismic Reflection to Uranium Exploration in Southwestern Songliao Basin

浅层地震反射波法和可控源音频大地电磁测量在铀矿勘查中各有优缺点。为了提高矿勘查提的效率,本文介绍了以可控源音频大地测量(CSAMT)为主、浅层地震反射波法为辅的综合物探方法在松辽盆地西南部铀矿勘查中的应用实例。通过CSAMT和浅层地震联合测量解释两条控盆断裂,查明四方台组和明水组顶底界面埋深约200~400m,呈椭圆形北东向分布,由盆地边部向凹陷中心地层由薄变厚;工作区基底埋深约700~1000m,呈宽缓波浪状展布;并对两种方法进行了对比分析:当勘探深度大于700m时,浅层地震反射波法对地层划分、查明基底埋深和基底断裂效果更好。经钻孔验证表明,合理利用CSAMT与浅层地震联合方法在松辽盆地西南部铀矿找矿工作中具有可靠、经济的优势,具有较强的应用价值。

The shallow seismic reflection method and CSAMT measurement have their own strengths and weaknesses in uranium exploration.In order to further enhance the efficiency of uranium exploration,this paper presents an application of combined geophysical prospecting using controlled source audio geodetic(CSAMT)and shallow seismic reflection in the southwest of the Songliao Basin.Interpretation of data from measurement by the two methods reveals two control faults of the basin.The interface between the Sifangtai Formation and the Mingshui Formation is about 200~400m deep,showing an elliptical northward distribution,of which the thickness becomes larger from the basin s edge to the depression center.The basement of the work area is about 700~1000m deep,extending in a broad and gentle wave-like manner.The effects of the two methods are compared.When the exploration depth is greater than 700m,the shallow seismic reflection method works better in stratigraphic division,determining the depth of basement and basement faults.Drilling proves that the combination of the CSAMT and shallow seismic method has a reliable and economic advantage in prospecting uranium deposits in the southwest of Songliao Basin and has a high application value.