ZHAO Ping1,2,3, LI Ai-ming4, LI Song-tao2,5, YANG Cheng-fu2, ZHAO Fu-yuan2, YAN Chun-jie1*, WANG Ze-peng2, CHEN Ju3,6, YANG Gang3,6
(1. Faculty of Materials Science and Chemistry, China University of Geosciences (Wuhan), Wuhan 430074, China;
2. Geological Party 105, Guizhou Provincial Bureau of Geology and Mineral Exploration and Development, Guiyang 550018, China; 3. Guiyang Supervision and Testing Center of Mineral Resources, Ministry of Land and Resources, Guiyang 550018, China; 4. Shanxi Research Institute of Rock and Mineral Analysis Application, Taiyuan 030001, China; 5. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; 6. Guizhou Central Laboratory of Geology and Mineral Resources, Guiyang 550018, China)
Abstract: The rare earth ore in the basalt weathering crust in the Northwestern Guizhou is a new type of rare earth ore with a wide distribution and high rare earth contents. In this paper, we have studied the petrology, mineral composition and geochemical characteristics of the REE ores from the layer of weathering crust using petrographic, mineralogical and geochemical methods, and explored the migration and enrichment mechanisms of the REE in this area. The results show that the REE ore layers in the weathering crust have varied thicknesses with single ore layer thickness of 0.1-0.5 m and total ore bed thickness of 5-15 m. The ores contain main mineral of kaolinite (60%-80%), and minor minerals of montmorillonite (2%-8%) and hematite (5%-20%). The ores have high total REE contents, varying from 144×10-6- to 2288×10-6, with characteristics of the LREE enrichment and the high REE contents in the kaolinite claystones. There are obviously negative Eu anomalies (0.22-0.85), and various Ce anomalies (0.86-1.63) in the REE patterns of the ores. The comprehensive analysis suggests that the REE enrichment of the basalt weathering crust is closely related to the content of kaolinite as the REE could be adsorbed by kaolinite particles under the relatively reduced environment.
Keywords: the basalt weathering crust; rare earth elements (REE); kaolinite; migration and enrichment; the Northwestern Guizhou
ACTA MINERALOGICA SINICA Vol. 39, No.4, 2019, page 464-473
