桂西田阳堆积型铝土矿矿物学及地球化学  

Mineralogy and Geochemistry of the Tianyang Accumulation-type Bauxite in Western Guangxi Province

作　　者：蔡书慧[1] 刘学飞[1] 孟健寅[1] 孙思磊[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083

出　　处：《地质与勘探》2012年第3期460-470,共11页Geology and Exploration

基　　金：广西地质矿产勘查开发局地质勘查项目(编号:桂地矿技【2008】02号)

摘　　要：桂西田阳堆积型铝土矿产于第四纪红土层中。本文通过对桂西田阳第四系堆积型铝土矿进行一系列矿物学与地球化学研究,探索铝土矿的物质来源。矿物学分析显示铝土矿石中主要矿物为硬水铝石、赤铁矿和锐钛矿,含有少量高岭石、鲕绿泥石、三水铝石、针铁矿、金红石、伊利石、蒙脱石和石英等。地球化学分析显示,组成铝土矿石的主要化学组分有Al2O3、Fe2O3、SiO2、TiO2、FeO和H2O+;微量元素分析显示,铝土矿石相对地壳和原始地幔富集B、Li、Ga、Zr、Hf、Nb、Ta、W、Th、U等元素,而亏损Ni、Cr等元素。矿石中明显富集稀土元素,稀土总量变化大,轻重稀土分异明显,轻稀土元素富集明显;矿石具有明显的铈异常和铕异常,且铕异常相对稳定,为一致的负异常。元素相关性分析显示常量元素间相关性较差;部分微量元素如Zr、Hf、Nb和Ta间呈现出较高的正相关性。通过Zr/Hf、Nb/Ta图解、Eu/Eu*-TiO2/Al2O3图解和Zr-Cr-Ga图解综合分析显示铝土矿物质来源复杂,底板碳酸盐岩和周围火成岩都为铝土矿提供物源。The Tianyang accumulation-type bauxite deposit in western Guangxi Province is located in the Quaternary ferrallitic soil beds. This work has made mineralogical and geochemical studies of the Tianyan accumulation-type bauxite to reveal the source material for the bauxite ores in this area. Mineralogical analyses show that diaspore, hematite and anatase are the main mineral components of the bauxite ores, with small amount of kaolinite, oolite chlorite,gibbsite, goethite, rntile, illite, montmorillonite and quartz. Geochemical data indicate that the main components are A1203, Fc203, SiO2 , TiO2 , FeO and H20＋. Trace element analysis shows that the bauxite ore is enriched in B, Li, Ga,Zr, Hf,Nb,Ta, W,Th and U, but tack of Ni and Cr con〉 pared with crust and original mantle. Ores are enriched in REE, .~, REE is greatly changed, HREE and LREE differentiate, and LREE are significantly en- riched. Ores display obvious Ce and Eu anomalies, and Eu anomalies are negative and relatively stable. Correlative analysis of the elements shows that the major elements are with low correlation ,and some trace elements such as Zr, Hf, Nb and Ta show a strong correlation. Geochemical indices such as Zr/Hf and Nb/Ta,Eu/Eu ＊ -TiO2/Al2O3 and Zr-Cr-Ga indicate that the source of material for bauxite ores is complex,and the underlying carbonate and surrounding igneous rack provided material for the formation of the bauxite deposit.

关 键 词：田阳 堆积型铝土矿 矿物学 地球化学 物质来源 

分 类 号：P618[天文地球—矿床学]