GAO Jun-bo, YANG Guang-hai, WANG Long-bo, YANG Rui-dong, CHEN Jun

(1. College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China;
2. Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China) 

Abstract: Lamprophyre bodies are widely distributed in the southeastern Guizhou, China. Their weathered crusts are commonly characterized with abnormally enriched various critical metal elements (REE, Nb, etc.). The distribution characteristics and occurrence modes of REE and Nb in the weathering crusts of lamprophyres in the Maping, Baifen, Sinantang areas have been studied in this paper. The results show that samples of the weathering crust of the Maping lamprophyre body are high in w(ΣREE) (avg. 1313.9×10-6 ), and w(Nb) (avg. 388.5×10-6), while those of the Baifen lamprophyre body are relatively low in w(ΣREE) (avg. 745.5×10-6 ), and Nb (avg. 152.3×10-6). In addition, samples of the weathering crust of the Sinantang lamprophyre body have relatively high w(ΣREE) (avg. 1245×10-6) contents but relatively low w(Nb) contents (avg. 160.5×10-6) comparing with those of the Baifen lamprophyre body. It is It is found that the REE of the weathering crust occurred mostly in the form of independent mineral of monazite, and partially occurred in the form of ion adsorption in clay minerals, while Nb mainly occurred in the Ti-rich phlogopite, anatase, rutile, and clay minerals.
 
Keywords: Nb; REE; occurrence state; weathering crust of lamprophyre; Zhenyuan

ACTA MINERALOGICA SINICA Vol. 41, No.4/5, 2021, page 548-557