矩形反演方法在航放测量中的应用

Application of Rectangle Invert Method of Airborne Radioactive Survey in the Exploration of Sandstone Tpye Uranium Deposit

在主攻北方盆地砂岩型铀矿背景下,航放测量面临新的挑战。多年来,航放测量一直采用半无限反演方法来计算放射性核素含量。采用半无限反演方法反演的信息用于区域铀成矿远景评价有其自身的优势,在砂岩型铀矿勘查中也取得了不少成果,但半无限反演方法较难反演诸如异常点、矿化点、含矿层、盖层高浓度的含氡断裂构造等局部辐射体。航放数据反演方法亟待发展与创新。文章详细介绍了一种适合盆地砂岩型铀矿勘查的航放数据反演方法—矩形反演方法,在航放异常筛选与查证、航放数据反演等方面作了许多探索,认为矩形反演方法较现行半无限反演方法能正确反演不同出露规模的辐射体,尤其是对具有找矿意义的局部辐射体的反演。研究提出了提取具固定半值点宽度峰形特征点作为砂岩型铀矿成矿有利信息的观点,并在巴音戈壁盆地塔木素地区取得较好应用效果。建议将矩形反演识别异常的标准以及信息提取技术进一步推广应用,以使航放测量更好地服务于我国砂岩型铀矿勘查。

For many years,aerial radioactivity measurements have always used semi-infinite inversion methods to calculate radionuclide content.The information retrieved by semi-infinite inversion method has its own advantages in evaluating regional uranium mineralization prospects,and has gotten a lot of achievements in the exploration of sandstone type uranium deposits.However,the semi-infinite inversion method is difficult to inverse local radiators such as mineralization anomalies,ore-bearing layers and radon-bearing fault structures beneath the sedimentary covers.The article introduced a rectangular inversion method in detail by screening and verifying the anomalies of retrieved airborne data.The research proposed the idea of extracting the peak shape of the fixed half-value point width as the favorable information of sandstone-type uranium mineralization,and has achieved good application effect in Tamusu area of Bayin Gobi Basin.It was believed that rectangular inversion can accurately invert radiations of different exposed scales compared with the current semi-infinite inversion,especially for the local radiations with prospecting significance.