龙源坝岩体铀矿化时空定位研究及其意义

Spatial temporal location of uranium mineralization in Longyuanba rock mass and its significance

研究区位于桃山-诸广铀成矿带南段的龙源坝复式杂岩体中南部。依据前期铀矿普查勘探总结的控矿构造和找矿标志,通过本文研究,查明龙源坝岩基过渡相是富铀场;燕山晚期第二阶段和第三阶段,沿NE向深大断裂侵入的酸性小岩体深部岩浆室是古地热体,串珠状展布的古地热体组成NE向条带状古地热场。古地热场侵入在过渡相富铀体内,在上部形成同形态、同规模的大硅化带。白垩世晚期是铀成矿期,矿岩时差约40 Ma。分析认为,NE向下南石、良伞寨、坪山3条大硅化带位于富铀场、古地热场、大硅化带重合区间,是有利的铀找矿远景区;硅质脉与不同方向构造交接处或岩性界面相交部位是有利的找矿靶区。对龙源坝岩体花岗岩内带型铀成矿时空规律的研究,可为华南众多的同类型铀资源潜力评价和找矿方向提供参考。

The study area is located in the middle and south of Longyuanba complex in the southern section of Taoshan-Zhuguang uranium metallogenic belt.According to the ore-controlling structure and prospecting criteria summarized in the previous uranium exploration,it is found that longyuanba rock base transition phase is a uranium-rich site through the study in this paper.In the second and third stages of late Yanshan period,the deep magma chambers of small acidic rocks invaded along the NE trending faults are paleo-geothermal bodies,and the beaded paleo-geothermal bodies form the ne-trending banded paleo-geothermal fields.The paleogeothermal field intruded into the uranium rich body of the transition phase and formed a large silicification zone with the same shape and size in the upper part.The late Cretaceous was a uranium mineralization period with a time difference of about 40 Ma.The analysis shows that the three large silicification zones in NE Xiananshi,Liangsanzhai and Pingshan are located in the overlap zone of uranium-rich field,paleogeothermal field and large silicification zone,which are favorable uranium prospecting prospects.The intersection of siliceous veins and structures in different directions or lithologic interfaces is a favorable prospecting target area.The study on the temporal and spatial regularity of uranium mineralization in granite inner zone of Longyuanba rock mass can provide reference for the evaluation and prospecting direction of many similar uranium resources in South China.