广东兴宁大坪地区花岗岩风化壳离子吸附型稀土矿成矿特征

Metallogenic Characteristics of Ion-adsorbed Rare Earth Deposits in Granite Weathering Crust in Daping Area,Xingning City,Guangdong Province

为探讨广东省兴宁市大坪地区花岗岩风化壳离子吸附型稀土矿的分布特点、富集规律和找矿标志,开展野外地质调查、人工冲击取样钻施工及样品分析测试等工作。结果表明,稀土矿主要赋存在花岗岩全风化层中,少量赋存在残坡积层和半风化层,产于花岗岩风化壳中;花岗岩风化壳结构模式自上而下可分为4层,有明显的分带性,稀土矿主要集中在风化壳中部的全风化层中;轻、重稀土在垂直方向上富集现象明显,轻稀土主要富集在全风化层,重稀土基本富集在半风化层上部;离子吸附型稀土矿主要受地形地貌、成矿母岩以及风化壳厚度的联合控制。

In order to investigate the distribution characteristics,enrichment rules and prospecting characteristics of ion-adsorbed rare earth deposits in granite weathering crust in Daping area,Xingning City,Guangdong Province,field geological survey,artificial impact sampling drill construction,sample analysis and testing were carried out.The results show that rare earth minerals mainly occur in the granite weathering layer,and a small amount of rare earth minerals occur in the residual slope deposit and semi regolith,and are produced in the granite weathering crust.The granite weathering crust structure pattern can be divided into 4 layers from top to bottom,with obvious zonation,and rare earth minerals mainly concen⁃trate in the whole weathering layer in the middle of the weathering crust.The accumulation of light and heavy rare earths in the vertical direction is obvious,the light rare earths are mainly enriched in the full regolith,and the heavy rare earths are basically enriched in the upper part of the semi-regolith.Ion-ad⁃sorbed rare earth deposits are mainly controlled by the combination of topography,ore-forming parent rock and weathering crust thickness.