黔北碳酸盐型铀矿床成因分析与指示意义  

Genetic Analysis and Indicative Significance of Carbonaceous Uranium Mineralization in Northern Guizhou

作　　者：王琼 吴林锋 刘开坤 彭松 范云飞 卢平 WANG Qiong;WU Linfeng;LIU Kaikun;PENG Song;FAN Yunfei;LU Ping(Non-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou,Guiyang,Guizhou 550005,China)

机构地区：[1]贵州省有色金属和核工业地质勘查局核资源地质调查院,贵州贵阳550005

出　　处：《世界核地质科学》2022年第3期426-436,共11页World Nuclear Geoscience

基　　金：贵州省有色金属和核工业地质勘查局核资源地质调查院“贵州省重要类型铀矿成矿规律与找矿预测研究”项目(编号:MCHC-ZG20212206-2)资助。

摘　　要：黔北地区为贵州省碳酸盐型铀矿(化)集中区,但有关铀矿床的研究资料却十分缺乏。通过在黔北地区对典型碳酸盐型铀矿床(点)进行野外地质调查、探槽和坑道铀矿石样品采集,开展了显微岩相学、扫描电镜-能谱分析、激光拉曼、碳氧同位素等研究。结果表明,铀矿体受断裂构造控制,铀矿脉中心部位因富含有机质而呈黑色、深灰色,铀矿石中的铀矿物主要为铀石,铀石与黄铁矿及“黑色”的有机质紧密共生,激光拉曼研究显示其具有焦沥青的特征。铀矿石中富含显示强浅蓝色荧光的轻质油包裹体,且严格平行于含矿微裂隙,指示了铀矿物的形成可能与烃类流体有关。碳同位素分析进一步证实了铀矿石中的有机质与其赋矿碳酸盐岩表现出明显的异源特征,且与贵州典型古油藏的碳同位素具有相似性,指示焦沥青可能来源于深部侵位的古油藏。微量、稀土元素分析表明,铀矿石的微量、稀土元素与深部牛蹄塘组富铀泥岩具有可比性。研究认为,黔北碳酸盐型铀矿床的形成与深部侵位的古油藏有关,铀成矿物质可能主要来源于深部牛蹄塘组富铀泥岩,铀矿床为受构造和古油藏联合控制的热液型铀矿床。Northern Guizhou is a cluster area of carbonaceous uranium mineralization,but few research on uranium deposits was reported.In this paper,through the field geological survey of typical carbonate uranium deposits(occurrence),and the collection of uranium ore samples in trenches and tunnels,microscopic petrography,scanning electron microscopy-energy dispersive analysis,laser Raman,C-O isotopes,etc.were carried out on the samples.This study showed that uranium ore bodies are controlled by fault structures,the center of uranium vein is black or dark gray because of its rich in organic matter.The uranium minerals in ores are mainly coffinite,which closely co-exist with pyrite and organic matter.Laser Raman research showed that it was with the characteristics of pyrobitumen.Uranium ore is rich in light oil inclusions with strong light blue fluorescence,and the distribution of ore bearing micro-fractures is strictly parallel,indicating that the formation of uranium minerals may be related to hydrocarbon fluids.C isotope analysis further confirmed that the organic matter in the uranium ore and its host carbonate rock showed obvious heterologous characteristics,and had similarities with the carbon isotope of typical paleo-oil reservoirs in Guizhou,indicating that the pyrobitumen may be derived from the deep paleo-oil reservoirs.The analysis of elements showed that the trace and rare earth elements of uranium ore are comparable with the uranium-rich mudstone of the deep Niutitang Formation.The study suggests that the formation of carbonaceous uranium mineralization in northern Guizhou was related to the deep emplaced paleo-oil reservoirs,and the ore-forming material may mainly come from the uranium-rich mudstone of the deep Niutitang Formation,uranium mineralization was caused by hydrothermal activity controlled by structure and paleo-reservoir.

关 键 词：有机质 铀矿化 碳酸盐型铀矿 黔北 

分 类 号：P619.14[天文地球—矿床学]