中国北方中新生代含铀盆地类型划分

Type classification of Mesozoic-Cenozoic uraniferous basins in northern China

含铀盆地类型划分是铀矿勘查工作的重要基础,目前对北方系列陆相盆地尚未开展过系统的对比研究工作。近年来,独具特色的砂岩型铀矿床跌宕成矿理论、"红-黑"岩系耦合沉积控矿、盆内隆缘控矿等新认识的提出,得益于我国北方砂岩型铀矿床的勘查实践,并在铀矿勘查中不断丰富和拓展应用,取得了一系列重要找矿突破。在此基础上,本文据北方陆相盆地30万余米岩芯勘探成果,以含铀岩系时代和盆地铀富集机理为基础,兼顾盆地构造位置及构造演化,首次提出了中国中新生代含铀盆地类型划分方案,分为三类含铀盆地:复合盆地、叠合盆地和简单盆地。复合盆地其含铀岩系均为中生代构造层;叠合盆地是含铀岩系为中生代和新生代两个构造层的产铀盆地,如准噶尔盆地、柴达木盆地;简单盆地其含铀岩系仅在新生代构造层产出,如龙川江盆地。根据不同含铀盆地类型与构造岩浆岩带的空间分布关系划分为两型,分别为构造岩浆岩带之间的开阔盆地和岩浆岩带内的山间盆地。含铀盆地类型的划分,不仅具有砂岩型铀矿成矿环境、成矿规律及成矿模式研究的重要成因指示意义,也可为目前正在开展的砂岩型铀矿勘查工作提供重要的实践指导。

The classification of uraniferous basin type is one of the most important foundation in uranium deposit prospecting, so far systematic comparative study of continental basins in northern China has not been carried out. Aided by prospecting practice of sandstone-type uranium deposits in northern China, unique sandsotone uranium metallogenic theory of fluctuating mineralization process,"Red & Black" syndepositional structures in ore-controlling, uplifts structures of basin margin in ore-controlling etc have been brought out, all the theories supervise prospecting and enriched through the practice, as a result prospecting breakthrough of sandstone-type uranium deposits was achived. Based on 30 million meters core information, on the basement of uraniferous formations time and uranium enrichment mechanisms, considering tectonic setting of basins and geotectonic evolution background, type classification of Mesozoic-Cenozoic uraniferous basins is proposed, including composite sedimentary basin, superimposed sedimentary basin and simple sedimentary basin. Composite sedimentary basin is a kind of uraniferous basin in which uraniferous formations are Mesozoic strata and sandstone-type uranium deposits lie in several formations, for example the uraniferous formations in Ordos Basin include Middle Jurassic uraniferous formation and Cretaceous formation. Superimposed sedimentary basin is a kind of uraniferous basin, uraniferous formations of which include Mesozoic structural layer and Cenozoic structural layer, for example, the Junggar Basin and Qaidam Basin. Simple sedimentary basin is a kind of uraniferous basin which only include Cenozoic uraniferous formations, for example, Longchuanjiang Basin. According to the space distribution between Tectonic magmatic belts and uraniferous basins, uraniferous basins are divided into the basin between magmatic belts and the basin in magmatic belts. Type classification of Mesozoic-Cenozoic uraniferous basins in northern China does not only have great significance in metallogenic environment of sandstone-type uranium deposits, metallogenic regularity and metallogenic model,but also in practical implications of prospecting.