SU Zhi-liang1, XUE Hong-fu1*, JIN Zhong-guo2, ZENG Dao-guo1, YE Lin3, XIANG Ming-kun1, DU Lin1, GUN Min-shan1, CAI Guo-sheng1, ZHANG An1, MANG Shi-cai1, ZENG Fan-xiang1, HUANG Zhi-long3
(1. Academy of Geological and Mineral Exploration, Guizhou Nonferrous Metal and Nuclear Industry Geological Exploration Bureau, Guiyang 550005;
2. Guizhou Nonferrous Metal and Nuclear Industry Geological Exploration Bureau, Guiyang 550005;
3. Stake Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081)
Abstract: Previous researched showed that a set of Fe-Al rock series which were hosted in the unconformity contact between the top of the Emeishan basalt and the overlying Xuanwei Formation (P3x)/Longtan Formation (P3l) are generally distributed in the northwestern Guizhou. They are characterized with obvious enrichment of the critical metal resources including Sc, Nb, and REE. In this paper, we have carried out the research on the distribution characteristics, enrichment regulations and occurrence forms of Sc, Nb, and REE in this Fe-Al rock series, and have given following conclusions. (1) Most of the key metals such as Sc, Nb and REE enriched in the Fe-Al rock series have reached the comprehensive utilization requirement with good prospecting potetial; (2) In the Fe-Al rock series of the Xuanwei Formation (P3x), Sc, Nb, and REE are evenly distributed with small differences. Sc is mainly concentrated in the lower part, Nb is mainly concentrated in the upper part, and REE is mainly concentrated in the middle and lower parts. The Sc, Nb, and REE are mainly hosted in tuffaceous ferrous claystone, oolitic bauxite-bearing claystone, and aluminous claystone; (3) In the Fe-Al rock series of the Longtan Formation (P3l), Sc is mainly distributed in the middle and southwest parts, Nb and REE are mainly distributed in the north and southwest parts, Sc is mainly concentrated in the lower part, and Nb and REE are mainly concentrated in the upper part of the Fe-Al rock series and the bottom of the overlying coal-bearing strata. Sc, Nb, and REE are mainly hosted in tuffaceous claystone, plant clastic claystone, and carbonaceous claystone; (4) Sc and Nb are mainly presented in the form of isomorphism in clay minerals, monazite, and rutile, while REE are presented in various forms such as ion adsorption, isomorphism, and independent minerals; (5) The enrichment of Sc, Nb, and REE has experienced the initial enrichment by weathering, and the re-enrichment by diagenetic reformation in the late period. In addition, the enrichment of Sc, Nb, and REE is closely related to the integrity of the Fe-Al rock series.
Keywords: Critical minerals; Fe-Al rock series; enrichment regulation; northwestern Guizhou
ACTA MINERALOGICA SINICA Vol. 41, No.4/5, 2021, page 520-530