华东南铀成矿省铀矿成岩成矿年代学研究现状及存在问题

华东南铀成矿省位于华南新构造区,是中国铀矿资源最为集中的成矿省,位于东经110°～120°,北纬24°～30°区域,呈带状集中分布在赣杭、桃山-诸广、武夷山3个铀成矿带,铀成矿类型主要包括花岗岩型、火山岩型。结合前人成果,收集了该区域典型矿床近10年同位素测年不同方法获得的成岩成矿年龄数据。通过对华东南铀成矿省的地质背景及主要铀矿床成岩-成矿时差统计分析,得出以下结论:成矿主要受华南大陆与华北板块完成拼合的印支运动,以及太平洋板块向欧亚板块俯冲形成的燕山运动影响。3个铀成矿带主要成矿期较为一致,分别是早白垩世早期、早白垩世晚期和晚白垩世。花岗岩岩体成岩集中在130～160 Ma,成矿作用在47～145 Ma都有分布。成岩-成矿二者在物质来源、地球动力学背景和条件等方面存在差异,可能为不同岩浆-流体成矿体系的产物。同时认为存在以下问题:由于测年方法、样品的不同导致同位素年代数据存在较大差异,影响了岩矿时差的准确测算。目前对成岩物质、成矿物质的精确测试和分析的研究较少。

The Research Status and Problems of Uranium Diagenesis and Metallogenic Chronology of the Uranium Metallogenic Province in South East China

The uranium mineral resources are mostly concentrated in the uranium metallogenic provinces, which are located in the Ganhang, Taozhu and Wuyishan uranium metallogenic belts, in the southern China neotectonic zone in south east China, between 110°~120° E and 24°~30° N. The uranium metallogenic types mainly include granite type and volcanic type. Based on the statistical analysis of the geological background and the time difference between diagenesis and mineralization of the main uranium deposits in the southern uranium metallogenic province of East China, the conclusions are drawn as follow by using the data of diagenetic and metallogenic ages which had been obtained by different isotopic dating methods for typical deposits in this region in recent 10 years. First, the mineralization was mainly influenced by both the Indo-Chinese Movement which was formed by the South China continent and the North China plate merging and the Yanshan Movement which was resulted in the Pacific plate subducted into the Eurasian plate. Second, the main metallogenic periods of the three uranium metallogenic belts were consistent, which were the early period of the Early Cretaceous, late period of the Early Cretaceous and the Late Cretaceous, respectively. Third, the diagenesis of granite bodies been concentrated in 130~160 Ma, and the uranium mineralization been occurred in 47~145Ma. Last, there are significantly differences between diagenesis and mineralization in material source, geodynamic background and conditions, etc., which might be the products of different magmatic-fluid mineralization systems. At the same time, the isotopic age data of different dating methods and samples vary greatly, which affects the accuracy of estimation of the time difference of diagenesis and uranium mineralization. Few studies have been found to focus on the discussion on the accurate testing and analysis of diagenetic and metallogenic materials.