青海省东昆仑八宝山地区砂岩型铀矿成矿条件及成矿潜力研究

Study on the metallogenic conditions and potential of sandstone-type uranium deposits in Babaoshan area in East Kunlun of Qinghai province

为明确青藏高原北部东昆仑八宝山地区砂岩型铀矿成矿潜力,基于砂岩型铀矿成矿理论,以晚三叠世八宝山组为目标地层,通过地质调查、化学样品分析等方法,研究了砂岩型铀矿5个重要成矿地质条件(铀源条件、古气候条件、岩性岩相条件、水文地质条件、构造条件)结果显示:研究区铀源丰富;成矿时期的气候处于干湿交替的阶段;赋矿岩性中的“泥-砂-泥”结构稳定;“补-径-排”水动力系统发育完善;辫状河相、三角洲相广泛分布;盆地边缘缓倾斜坡带特征明显。结合岩石地球化学特征及已有成矿事实表明,东昆仑八宝山地区砂岩型铀矿成矿地质条件较好、找矿潜力较大。

In order to clarify the metallogenic potential of sandstone-type uranium deposits in Babaoshan area,East Kunlun in Northern Qinghai-Tibet Plateau,based on the metallogenic theory of sandstone-type uranium deposits,Babaoshan formation in Late Triassic is taken as the research target in this paper to study five important metallogenic geological conditions(uranium source,paleoclimate,lithology and lithofacies,hydrogeology and structure)of sandstone-type uranium deposits through geological survey and chemical sample analysis.The results show that there are abundant uranium sources in the study area;the climate of mineralization period is in the alternation of drying and wetting;the structure of“mud-sand-mud”is stable in ore bearing lithology;the hydrodynamic system of“replenishment-runoff-discharge”is perfect;braided river facies and delta facies are widely distributed in the study area;the characteristics of gently inclined slope zone in the basin margin are obvious.According to the geochemical characteristics of rocks and the existing mineralization,the geological conditions of sandstone-type uranium deposits in Babaoshan area in East Kunlun are good with great prospecting potential.