黔中蔡家坝铝土矿床微量元素特征及地质意义  

Geochemical characteristics and significance of trace elements in Caijiaba bauxite deposit, Guizhou Province

作　　者：陈晓甫[1,2] 吴攀 刘江[3] 邓克勇 刘亚彬 魏涛 冉文瑞 Chen Xiaofu;Wu Pan;Liu Jiang;Deng Keyong;Liu Yabin;Wei Tao;Ran Wenrui(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025;Natural Resources Survey and Planning Institute of Guizhou Province,Guiyang 550004;No.1 Institute of Non-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou,Guiyang 551400;Guizhou Geological Survey,Guiyang 550081)

机构地区：[1]贵州大学资源与环境工程学院,贵阳550025 [2]贵州省自然资源勘测规划研究院,贵阳550004 [3]贵州省有色金属和核工业地质勘查局一总队,贵阳551400 [4]贵州省地质调查院,贵阳550081

出　　处：《地质科学》2022年第3期879-896,共18页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：贵州省科技计划项目(编号:黔科合平台人才[2016]5664)资助。

摘　　要：贵州清镇蔡家坝铝土矿床赋矿层位为下石炭统九架炉组(Cjj),下伏地层中-上寒武统清虚洞组(∈_(2-3)q)。本研究以九架炉组含铝岩系与顶底板为主要研究对象,通过对Be、Th、U、Sr、Ba、V、Ni、Cr、Zr等沉积环境指示性较强的微量元素以及稀土元素测试分析,结合Th/U、Ni/Cr、Sr/Ba等二元图解和稀土元素标准化图解综合研究,探讨研究区铝土矿床的物质来源、成矿环境及稀土分异控制因素。研究结果表明:1)研究区铝土矿床形成于以陆相沉积为主,海陆交互的还原环境,成矿作用为风化—沉积成因,有异地沉积等成矿物质多源特征,下伏中-上寒武统清虚洞组为矿区物源之一;2)研究区含铝岩系ΣREE值最高831.63×10^(-6),ΣLREE/ΣHREE比值为4.68~13.77,表现为轻稀土富集型;3)pH值、粘土矿物以及Fe矿物可能共同主导了蔡家坝含铝岩系中REE的富集以及LREE和HREE的分异。The Caijiaba bauxite deposit occurs in the Jiujialu Formation of the Lower Carboniferous with the roof and floor of bauxite and the bauxite layer as the main research objective. In this study, we explored the material source, metallogenic environment and REE possible enrichment mechanism in the Caijiaba bauxite deposits using the geochemical characteristics of trace elements and rare earth elements that are highly indicative of the sedimentary environment, such as Be, Th, U, Sr, Ba, V, Ni, Cr, Zr, and combined with binary diagrams of Th/U, Ni/Cr, Sr/Ba and standardized diagrams of rare earth elements. This analysis indicates that depositional setting of Caijiaba bauxite deposit that was a land-sea interactive setting dominated by continental sedimentary setting, and the mineralization was characterized by weathering and deposition in the mineralization was characterized by weathering and deposition in the reducing environment. The carbonate rocks Middle-Upper Cambrian Qingxudong Formation was one of the mineral sources in this area. The aluminum-bearing rock had a higher REE value, characterized by enriched LREE. On the other hand, enrichment and differentiation of REE in Caijiaba bauxite may be caused by certain pH value, clay minerals and Fe minerals.

关 键 词：微量元素 稀土元素 地球化学特征 铝土矿 蔡家坝 

分 类 号：P611.2[天文地球—矿床学] P618.7[天文地球—地质学]