华南相山铀矿田成矿条件及发展前景

华南中生代陆相火山岩分布广泛，火山活动起始于１７５Ｍａ，结束于７５Ｍａ，早期为高钾钙碱系列、晚期以双峰式火山岩为特征。与火山岩有关的铀矿床不仅数量多、储量大，而且矿化类型也比较复杂，因而引起国内外地质学家的关注。位于华南中生代陆相火山岩带西缘的相山矿田是我国火山岩型铀矿床的典型代表。矿田受区域构造和火山构造联合控制。组成火山盆地盖层的主体岩性为晚侏罗世的碎斑熔岩和流纹英安岩，基底为震旦纪变质岩。与碱交代有关的早期铀矿化分布在盆地的东部，与酸碱交替交代有关的铀、钍矿化分布在盆地西部。矿化垂幅达千米。矿田具有良好的成矿条件。近几年由于基础工作和科研工作的加强，矿田地质勘查取得了令人瞩目的进展，一批新矿床被发现，老矿床不断扩大。其中邹家山矿床已跨入超大型铀矿床的行列，表明相山矿田具有较大的找矿潜力。

METALLOGENETIC CONDITIONS AND PROSPECTS OF THE XIANGSHAN URANIUM OREFIELD IN SOUTH CHINA

The Mesozoic continental volcanic rocks are widely distributed in South China. Volcanicactivities started at 175 Ma and ended at 75 Ma. They are characterized by highly potassiccafe-alkaline volcanic series at the early stage and bimodal volcanic rocks at the late stage. Uranium dposits related to volcanic rocks not only are large in quantity,abundant in reserves,but also are more complex in types of mineralization,therefore they have aroused the attention of geologists at home and abroad.The Xiangshan orefield,located at the western margin of the Mesozoic continental volcanic belt in South China, is a typical representative of volcanic type uranium deposit inChina. The orefield is jointly controlled by regional and volcanic structures. Main host rockswhich constitute the cover of volcanic basins are the Late Jurassic porphyroclastic lava andrhyodacite, the basement consists of Sinian metamorphic rocks. Uranium mineralization at theearly stage related to alkali-metasomatism is distributed in the east of the basin and uranium(thorium) mineralization related to the alternation of acidic and alkalic metasomatism (alteration) is distributed in the west of the basin. The vertical amplitude of mineralization is up toone thousand meters. The orefield has good metallogenetic conditions.In recent years,owing to the intensification on basic geological and research work,remarkable progress has been made in the geological exploration of the orefield. A batch of newdeposits have been discovered and old deposits are being enlarged constantly. Of them,theZoujiashan deposit has ranked among the superlarge uranium deposits, indicating that theXiangshan orefield has a large prospecting potential.