铀矿地质

本文重点研究了相山铀矿田的成矿时代及成矿环境 ,并剖析了典型矿床在垂向上物质成份的变化规律。研究结果表明 :相山矿田主要经历了两期铀矿化作用 ,第一期为铀 赤铁矿化阶段 ,成矿年龄为 1 1 5± 0 6Ma ;第二期为铀 萤石 水云母化阶段 ,成矿年龄为 99± 6Ma。两期成矿作用分别形成于不同的地质环境 ,第一期成矿作用主要与大规模火山塌陷及次火山岩侵位有关 ,第二期成矿作用则主要与因太平洋板块的松弛作用而形成的区域性伸展、裂解及中基性脉岩的活动有关。相山矿田的热液蚀变类型不仅在平面上存在东碱、西酸的演化趋势 ,而且在垂向上还存在上酸、下碱的演化规律。通过对相山矿田成矿机理的深入探讨 ,认为相山矿田是成矿元素多阶段富集、成矿热液多期叠加以及多种地质因素共同作用的产物。

This paper puts emphasis on the study of metallogenetic ages and environment,anatomizes the vertical variation regularities of matter composition at representative deposits.The results indicate that there are two uranium mineralization phases in Xiangshan uranium ore field,The first phase of mineralization (uranium haematite) took place at 115±0 6 Ma associated with the volcanic collapse and the intrusion of subvolcanic magma.The second phase of mineralization (uranium fluorite hydromica) occurred at 99±6 Ma and was related to the regional extension and intrusion of intermediate basic dikes caused by the relax of the Pacific Plate subduction.In Xiangshan ore field,there is a horizontal alteration trend with alkaline alteration in the eastern part and acidic alteration in the western part,meanwhile a vertical alteration trend with alkaline alteration at depth and acidic alteration at shallower level.Based on the discussion of metallogenetic mechanism in Xiangshan uranium ore field,it is suggested that the mineralization of the Xiangshan uranium ore field resulted from the combination of multiple stage uranium enrichment,superimposition of multiple stage hydrothermal alterations and many other geological factors.