黔西北峨眉山玄武岩顶部Fe-Al岩系特征及其三稀元素富集特点

黔西北峨眉山玄武岩顶部普遍发育Fe-Al岩系。为查明峨眉山玄武岩顶部Fe-Al岩系特征,探讨其三稀元素富集特点,开展了针对峨眉山玄武岩顶部Fe-Al岩系的野外调查。调查结果显示: 当峨眉山玄武岩上覆地层分别为宣威组或龙潭组时,峨眉山玄武岩顶部风化壳Fe-Al岩系表现出明显差异。样品测试结果表明: Fe-Al岩系内Sc、Nb、REE等三稀元素含量丰富,具有很好的找矿前景,宣威组Fe-Al岩系内Sc、Nb、REE含量更高,尤其是Nb和REE。Fe-Al岩系内Sc、Nb、REE等三稀元素富集为峨眉山玄武岩风化初始富集和后期改造再次富集作用的结果。

Characteristics of Fe-Al rock series on the top of Emeishan basalt in northwestern Guizhou Province and enrichment characteristics of its three rare elements

The Fe-Al rock series is widely developed on the top of the Emeishan basalt in northwestern Guizhou Province. In order to ascertain the characteristics of the Fe-Al rock series and explore the enrichment characteristics of its three rare elements, the authors carried out a field survey on it. The results show that the Fe-Al rock series as the weathering crust at the top of the Emeishan basalt is apparently different when the overlying stratum is Xuanwei Formation (P₃x) or Longtan Formation(P₃l). Sample test results show that the Fe-Al rock series is rich in three rare elements such as Sc, Nb, REE, with great prospecting prospects. The Sc, Nb and REE contents of the Fe-Al rock series with Xuanwei Formation (P₃x) is higher than that of the Fe-Al rock series with Longtan Formation (P₃l), especially Nb and REE. The Sc, Nb and REE concentration in the Fe-Al rock series is an outcome of combined action of the initial enrichment weathering and the late beneficiation reformation on the Emeishan basalt.