Discovery of the REE minerals and its geological significance in the Quyang bauxite deposit, West Guangxi, China
Discovery of the REE minerals and its geological significance in the Quyang bauxite deposit, West Guangxi, China
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DOI：
10.1016/j.jseaes.2010.05.005
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发表时间：
2010-11-09
影响因子：
3
通讯作者：
Zhou, Fang
中科院分区：
文献类型：
--
作者：
Wang, Qingfei;Deng, Jun;Zhou, Fang
我国岩溶型铝土矿大多富集稀土元素，一般认为稀土元素以离子态吸附在粘土或一水硬铝石矿物表面。然而，稀土矿物在铝土矿中的赋存状态至今未见报道。在广西曲阳铝土矿存款中发现稀土矿物。矿物为绿柱石和白榴石。榴辉岩广泛分布于鲕粒和杂基中，引起矿石的Ce正异常;而教会石很少，产于鲕粒的核部。稀土元素矿物组成表明Eu异常在风化过程中变化平缓，Eu异常分析表明矿石中的稀土元素主要来源于下伏碳酸盐岩。铝土矿形成于碱性条件下，而钙铝石形成于酸性条件下，两种矿物共存于矿石中，表明二叠纪铝土矿形成环境复杂，pH值变化大。此外，推断Parchite形成早于Churchite。(C)2010爱思唯尔有限公司版权所有。
Most of the karstic bauxite deposits in China are enriched in REE, and the REE has commonly been considered to be adsorbed on the surface of clay or diaspore minerals as ion state. However, occurrence of REE minerals in the bauxite deposits has not been reported by far. In the Quyang bauxite deposit from Guangxi province, we find REE minerals. The minerals are parisite and churchite. Parisite is widely distributed in the ooids and matrix, inducing positive Ce anomaly of the ores; whereas, churchite is rare and occurred in the core of ooid. The compositions of the REE minerals show the Eu anomaly can change gently during the weathering, and the Eu anomaly analyses suggest that the REE in the ores are mostly derived from the underlying carbonates. The parisite is formed in an alkaline condition, while churchite in an acidic situation; the co-existence of the two minerals in the ores suggests the Permian environment for bauxite formation is complex with great change of pH value. Moreover, parisite is inferred to be formed earlier than the churchite. (C) 2010 Elsevier Ltd. All rights reserved.