非线性数字频谱方法体系与表生铀元素组合迁移能力定量分析

Sandstone-type uranium deposits have become an important type of uranium deposits. The research on mineralization theory and resource potential evaluation of sandstone-type uranium deposit has been incorporated into the development strategy for national important energy. The Ordos continental basin has become a world-class and large-scale sandstone-type uranium deposit, the supergene uranium geochemistry in the basin periphery belongs to the indispensable research content. Since Mesozoic and Cenozoic, uranium elements existed in uranium-bearing rock series in the basin periphery have undergone a migration period with oscillatory cycles for nearly 200 million, so the geochemical data of one-time observation inevitably carry certain geological information. Therefore, this project intends to take the northern of Ordos basin periphery as a case, based on the 1∶200,000 geochemical soil survey data to establish a nonlinear digital frequency spectrum method system. According to the key contents on the types, spatial distribution and variation characteristics and migration ability of uranium elements combination in the supergene uranium geochemistry of basin periphery are discussed, and the scientific problem is the non-linear modeling process for migration system aiming at characteristics information released by the elements affinity and dynamic laws contained in geochemical data elements. This is not only instructive for elucidating the uranium source for the large-scale sandstone uranium deposits of the northern of Ordos Basin periphery, but also provides the quantitative basis for large-scale metallogenetic analysis of sandstone-type uranium deposits and provides important results for big data potential evaluation of sandstone-type uranium resources.

砂岩型铀矿已经成为重要铀矿类型，有关砂岩型铀矿成矿理论及资源潜力评价研究已纳入国家重要能源发展战略。鄂尔多斯陆相盆地已成为世界级超大型砂岩铀矿产地，盆地外围表生铀地球化学属于不可或缺的研究内容。由于中新生代以来盆地外围含铀母岩系中的铀元素历经近2亿年的周期震荡性迁移过程，则一次性观测的地球化学数据必然携带某些地学信息。因此，本项目拟以鄂尔多斯盆地北缘为案例，基于1∶20万地球化学土壤测量数据建立适用性的非线性数字频谱方法体系，针对盆地外围表生铀地球化学中铀元素组合的类型、空间分布与变异特征、迁移能力等关键内容展开探讨，其科学问题是针对地球化学数据蕴含的元素亲和性及动力学规律所释放出的特征信息进行迁移系统的非线性建模过程。这不仅对阐明鄂尔多斯盆地北缘超大型砂岩铀矿的铀源问题具有指导意义，而且可为砂岩型铀矿大规模成矿分析提供定量依据，为砂岩型铀矿资源大数据潜力评价提供重要成果。

砂岩型铀矿是陆相盆地内形成的沉积矿床，因其规模巨大而成为我国重要的核能资源。基于地质数据的砂岩型铀矿资源潜力评价是国家基础研究立项课题，其核心技术则是表生成铀复杂系统的数据分析。表生作用下的铀元素组合历经风化、迁移过程于沉积盆地内聚集成矿，补-径-排-聚构成成矿系统的四大要素，其成矿系统要素分析可归结为盆地外围含铀母岩系的供铀能力与盆地钻孔测井数据的聚铀能力的综合分析。.本项目研究是基于表生地球化学取样数据所建立的数字频谱模型，此模型属于非线性，包括：非线性降维降噪分析，基于傅里叶变换的数字谱模型分析，基于网格型数字谱空间收敛分析，基于空间收敛点的通量积分计算等。其核心科学问题在于：在表生成铀复杂系统地质背景分析基础上，运用区域1∶20万比例尺地球化学土壤观测样本数据进行铀元素地球化学亲和性计算，提取不同类型的亲铀因子，依其振荡属性建立地质空间数字频谱模型，以度量亲铀因子的空间分布强度，再依其空间收敛性计算亲铀因子的空间通量，提供供铀能力的总体指标。