贵州西部峨眉山玄武岩风化壳稀土元素迁移富集规律研究

Rare Earth Element Migration and Enrichment of Weathered Crust of Emeishan Basalt from West Guizhou Province

通过野外地质调查、样品采集和ICP-MS分析等方法,运用地质学和地球化学理论,对贵州西部峨眉山玄武岩风化壳稀土元素迁移富集规律进行研究。研究结果表明:峨眉山玄武岩风化壳剖面垂向上,各稀土元素氧化物含量变化曲线呈"D"字型,浸出率呈上陡下缓"单齿"状曲线。在全风化-半风化层中,各稀土元素整体富集,而亚黏土层中,仅Yb,Lu,Ce三个元素富集。全风化-半风化层中,稀土元素氧化物总量变化范围847~1146×10^(-6),平均品位为973×10^(-6),浸出率变化范围15.2~45.2×10^(-2),平均浸出率为26.3×10^(-2)。各稀土元素氧化物浸出率一般20%~70%,轻、中、重稀土氧化物总量平均浸出率分别为25.5%,33.0%及24.3%。Ce,Nd,La,Y四个元素氧化物总量及其浸出量分别平均占比稀土元素氧化物总量的76.3%和71.1%,因而,贵州西部峨眉山玄武岩风化壳型稀土资源,主要为富Ce-Nd-La-Y型。此研究结果对扩大我国稀土矿源具有重要的意义。

By field geological investigation,sampling and ICP-MS analysis,etc.and applying the theories of geosciences and geochemistry,the migration and enrichment laws of rare earth elements(REEs)of the weathering crust of Ermeishan Basalt in western Guizhou Province were studied.The results indicated that in vertical view,the contents of various REE oxides of the weathering crust of Ermeishan Basalt varied in“D”shaped curves;in the loam layer,only Yb,Lu and Ce elements were enriched.In the completely to semi-weathered layer,the total REE content ranged from 847×10^(-6) to 1146×10^(-6),with an average of 973×10^(-6) and the leading rate varied from 15.2×10^(-2) to 45.2×10^(-2),with an average of 26.3×10^(-2).The leaching rates of various REE oxides generally ranged from 20%to 70%;the average leaching rates of total LREEs,MREEs and HREEs were 25.5%,33.0%and 24.3%,respectively.The total content and the average leaching rate of Ce,Nd,La and Y oxides account for 76.3%and 71.1%respectively for total REE oxides.Accordingly,the REE resources of the weathering crust of Ermeishan Basalt in western Guizhou province are mainly a Ce-Nd-La-Y enriched type.This is of great significance to expanding China’s REE resources.