汪小妹;焦养泉;杜远生;周琦;崔滔;计波;雷志远;翁申富;金中国;熊星;

• 1:中国地质大学资源学院
• 2:中国地质大学构造与油气资源教育部重点实验室
• 3:中国地质大学生物地质与环境地质国家重点实验室
• 4:贵州省地质矿产勘查开发局

摘要(Abstract)：

选取新模向斜的一个钻孔剖面,对铝土矿的矿物组成及稀土元素地球化学特征进行了研究。铝土矿矿石矿物以一水硬铝石为主,另有少量一水软铝石。其次为高岭石、绿泥石等黏土矿物,以及少量重矿物。此外,在含矿岩系近底部还发现有富集Ce元素的矿物氟菱钙铈矿[Ce2Ca(CO3)3F2]。从剖面顶部至底部,铝土矿中稀土元素含量呈逐渐增加的趋势,且稀土元素参数LaN/YbN、LaN/SmN和GdN/YbN的数值均随深度逐渐增大。说明从剖面顶部至底部,稀土元素的淋滤迁出逐渐减弱,且稀土元素间存在一定的分异。稀土元素间的分异可能由不同的含稀土元素矿物抗风化淋滤差异所致。铝土矿稀土元素配分模式表现为LREE明显富集、MREE中等-弱富集、HREE相对平坦的特征,且具有明显的正Ce异常。δCe异常值随深度增加逐渐减小,接近含矿岩系底部,δCe异常值再次增大。含矿岩系上部的Ce异常是由氧化条件下Ce3+向Ce4+转变并形成方铈矿(CeO2)所致。随着深度的增加,含矿岩系的氧化性逐渐减弱,从而δCe异常值逐渐减小。接近含矿岩系底部,由于氟菱钙铈矿[Ce2Ca(CO3)3F2]的形成,导致δCe异常值再次增大。氟菱钙铈矿的沉淀可通过氟化物络合物(CeF2+或CeCO3F0)与Ca2+和HCO3-发生反应来完成。

关键词(KeyWords)： 铝土矿;稀土元素;地球化学;务正道地区

Abstract:

Keywords:

基金项目(Foundation): 贵州省地勘基金项目“贵州务正道地区铝土矿基础地质与成矿规律研究”;; 国家自然科学基金项目(41202114);; 中国博士后科学基金项目(2012M521499);; 中央高校基本科研业务费专项资金项目(CUGL100253)

作者(Author): 汪小妹;焦养泉;杜远生;周琦;崔滔;计波;雷志远;翁申富;金中国;熊星;

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