江西相山巴泉隐爆角砾岩型铀矿床地质特征及形成过程

Geological characteristics and formation process of the Baquan cryptoexplosive breccia-type uranium ore deposit in Xiangshan,Jiangxi

以相山巴泉隐爆角砾岩型铀矿床为研究对象,介绍该矿床的成矿地质背景及矿床地质特征,探讨隐爆角砾岩的形成过程及铀成矿过程。相山巴泉隐爆角砾岩受火山机构制约,成岩成矿作用与火山—次火山作用密切相关。铀矿化与隐爆角砾岩(筒)在时空上具有密切关系,矿化严格受岩筒控制,且产于岩筒内及其接触带附近裂隙中。矿化与岩筒范围、形态相吻合,矿体与岩筒产状相同。矿化富集程度与岩筒内的角砾大小密切相关,角砾愈小矿化愈富集。矿化在水平和垂直方向上也呈规律性变化,自隐爆角砾岩(筒)中心至边缘、从顶部至底部,铀矿品位逐渐降低。

With the Baquan cryptoexplosive breccia-type uranium ore deposit as an objective, we summarize geological background and geological characteristics of the deposit, and discuss the formation process of cryptoexplosive breccia and uranium deposit. Constrained by its volcanic edifice, diagenetic min- eralization is closely related to subvolcano and volcanism. It can be inferred that uranium mineralization is spatially and temporally related to and controlled by the cryptoexplosive breccia, and occurs mainly in pipes and fractures close to contact zones. Uranium mineralization couples with pipe range and morphology and orebodies have the same occurrence as pipes. The enrichment degree of uranium mineralization is closely related to the size of the breccias, the smaller breciccas, the higher mineralization. On the other hand, uranium mineralization also shows regular changes in vertical and horizontal directions, with ore grade decreasing gradually from center to edge and from top to bottom of the cryptoexplosive breccia （pipes）.