湘桂地区中新生代走滑断裂系统对铀成矿的控制作用

湘桂地区是我国的重要铀成矿区之一。该区自中生代末期以来进入了全新的陆内走滑作用阶段,并经历了两次重大的构造转换,即晚三叠纪末至侏罗纪末的会聚走滑和白垩纪至第三纪早期的离散走滑。三条NNE向的主走滑断裂(PDZ)和一系列NE向的同向右侧列走滑断层(P)以及NW向的反向走滑断层(R')组成了复杂的走滑断裂网络系统,并直接控制了湘桂地区铀矿床(田)在时间和空间上的分布。

MESOZOIC-CENOZOIC CONTINENTAL STRIKE-SLIP FAULT SYSTEM AND ITS ROLES ON URANIUM MINERALIZATION IN HUNAN AND GUANGXI, CHINA

The southern Hunan northwestern Guangxi region is one of the most important uranium metallogenic zones in China. Mesozoic geology of this area is predominated by continental strike slip deformation that resulted from the oblique subduction of the palaeo Pacific plate underneath east China continent since the Late Triassic Early Jurassic. Regional structural analyses indicate that the strike slip fault system evolves at two stages under distinct tectonic regimes, i.e., transpressional stage in the whole Jurassic and transtensional stage from Early Cretaceous to early Tertiary. Three NNE striking principal strike slip faults and their subsidiary P fault (NE trending) and R′ fault (NW trending) form a complex fault network that plays significant roles on the formation and distribution of the Mesozoic uranium rich granites and fault basins. The intimately spatial and temporal relationship between uranium deposits and strike slip faults demonstrates that uranium mineralization results from transtensional activity of this huge strike slip fault system.