摘要
伽马能谱测量是一种寻找铀矿的直接方法,但是产于中新生代沉积盆地中的砂岩型铀矿,由于其矿化品位较低,埋藏深,伽马能谱测量结果具有强度低、变化平稳,无明显的放射性异常信息,常规的数据处理方法(如单元素分布趋势分析和单元素比值)难以识别。在此情况下,选择航空伽马能谱测量的U、Th、K元素参数进行组合,同时给出了多元素组合参数的数学模型、选择目的及其地质意义,增强和提取与砂岩型铀矿成矿有关的伽马能谱数据的微弱信息,利用数理统计分析中的聚类分析、逻辑回归分析进行综合评价,从铀源和铀的活化迁移富集系数方面给出了砂岩型铀矿的成矿概率。试验证明与常规方法相比,采用多元素组合参数对十红滩、阿右旗已知地区的航空伽马能谱测量数据进行微弱信息增强和提取,砂岩型铀矿找矿的微弱信息得到明显增强。因此,航空伽马能谱测量数据的多元素组合参数增强微弱信息,作为预测砂岩型铀矿成矿有利区的有效方法,对砂岩型铀矿找矿具有一定的地质意义和适用性。
Gamma energy spectral survey is a direct method for uranium prospecting. However, because of lower grades and deep burial, sandstone type uranium deposits occurring in Meso-Cenozoic sedimentary basins have low and uniform gamma-ray values and show no pronounced radioactive anomaly information in the airborne gamma spectral measurements above and around a uranium orebody. So the anomaly is difficult to recognize using conventional data processing methods （e.g. mono-element distribution trend analysis and mono-element ratio）. In this case, the element parameters U, Th and K are combined for the airborne gamma spectral measurements, and furthermore, the authors have constructed a mathematical model of multi-element combination parameters to enhance and extract weak information of gamma energy spectral data relating to sandstone type uranium deposits, used the cluster analysis and logical regression analysis in the mathematical statistics to perform integrated evaluation of the prospect area and gave the metallogenetic probability of sandstone type uranium deposits. Experiments demonstrate that, in comparison with routine methods, the use of multi-element combination parameters to enhance and extract weak information of airborne gamma energy spectral data from the Shihongtan and Alxa Youqi areas can significantly enhance weak information about prospecting of sandstone type uranium deposits. Therefore, this method is an effective and applicable method for forecasting areas favorable for sandstone type uranium mineralization.
出处
《中国地质》
CAS
CSCD
2007年第3期478-485,共8页
Geology in China
基金
国家重点基础研究发展计划(973)项目(2003CB214604)资助。
关键词
航空伽马能谱
多元素组合参数
微弱信息增强
砂岩型铀矿
multi-element combination parameters
airborne gamma energy spectrometry
weak information enhancement and extraction
sandstone type uranium deposits
