柴西南缘新近系铀储层发育与铀成矿水文地质条件分析

柴达木西南缘花土沟地区新近系上油砂山组是重要的含铀岩系之一,其水文地质条件与铀成矿关系密切。通过分析地下水类型、水化学特征等,结合野外地质调查资料,认为本地区基底和盖层富铀,风化剥蚀后随地下水搬运至盆地内富集成矿,提供铀源;上油砂山组时期西北高东南低的构造格局,控制含氧含铀地下水的渗流方向;辫状河三角洲平原分流河道水动力适于铀矿沉淀富集成矿,成为潜在的铀储层;上新世末期含氧含铀流体下渗进入上油砂山组潜在铀储层中被还原,最终成矿。

Analysis of Neogene uranium reservoir development and uranium mineralization hydrogeological conditions in Southwest Qaidam Basin

The Neogene upper Youshashan formation in Huatugou area, Southwestern Qaidam, is one of the most important uranium bearing rock series. Its uranium reservoir development and uranium mineralization are closely related to hydrogeological conditions. The basement and caprock are rich in uranium, which are transported to the basin with groundwater after weathering and denudation to provide uranium source. During the period of upper Youshashan formation, the tectonic pattern of high in Northwest and low in Southeast controlled the seepage direction of oxygen-bearing uranium groundwater; the hydrodynamic force of distributary channel in braided river delta plain was suitable for uranium deposit enrichment and mineralization, becoming potential uranium reservoir; at the end of Pliocene, oxygen-bearing uranium fluid infiltrated into the potential uranium reservoir of upper Youshashan formation and was reduced and finally mineralized.