万洋山—诸广山花岗岩带铀成矿的区域地质背景

万洋山—诸广山复式花岗岩带,经历多期次的构造-岩浆活动,受到东西向和南北向的深部构造控制。岩带内北东、北北东、东西、南北及北西向五组线型断裂构造及规模不一的中心型环状构造发育。铀成矿的时空分布,受中生代南北向和东西向构造-岩浆活动带交汇区的宏观制约。矿床定位与中心型小环状构造交切及不同方向的线型断裂交叉密切有关。矿源既来自铀源层和花岗岩,也来自上地幔岩浆源。区域内地质-成矿事件复杂,经过了槽、台、洼三大演化阶段。地洼阶段构造-岩浆活动次数最多,最强烈。铀成矿作用形成于地洼阶段中晚期,即白垩-第三纪。铀成矿以内生热液(热水)为主,叠加有后生淋积矿化。

REGIONAL GEOLOGICAL BACKGROUND OF URANIUM METALLOGENESIS IN WANYANGSHANZHUGUANGSHAN GRANITIC ZONE

Wanyangshan--Zhuguangshan composite granitic zone is controlled by EW and SN trending infracrustal structures and has undergone multiple tecto-magmaotic activities, in which NE, NNE, EW, SN, NW linear structures and central type ring structures varying in dimension are developped. The temporal and spatial distribution of uranium mineralization is generally controlled by the intersection areas of SN trending tecto-magmatic active zones with EW trending ones.The location of uranium deposits is closely related to the cross position of little scale central type ring structures and to the intersection of linear structures of various strikes. The ore-forming material comes mostly from the uranium source beds, granites and also from upper mantle derived magmas. Uranium mineralization mainly occurs as endogenic hydrothermal mineralization superimposed by epigenetic infiltrating type of uranium mineralization.