WANG Biao1, HUANG Qing1*, HE Liang-lun1,3, LYU Shao-yu1, XU Ying2, XIONG Xing-yu1, ZHAO Ting1
(1. The 113 Geological Team, Bureau of Geology and Mineral Resources Exploration and Development of Guizhou Province, Liupanshui 553000, China;
2. Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of
Geological Sciences, Chengdu 610041, China;
3. Technical Innovation Center of Mineral Resources Exploration Engineering in Bedrock Zones, Ministry of Natural Resources, Guiyang 550081, China)
Abstract: Sedimentary type REE deposits are generally developed at the bottom of the Xuanwei Formation in the northwestern Guizhou. Their orebodies are characterized with high REO grade, large thickness, layered distribution, and stable bed, with associated metal minerals including niobium, scandium, and titanium. There is great prospecting potential of REE resources in the bottom part of the Xuanwei Formation in the northwestern Guizhou. Previous researches of this sedimentary type REE deposit are mostly focused on studying its metallogenic regularity and metallogenic mechanism, but rarely involved in studying the occurrence state of the REE in this type of REE deposit. In this paper, we have chosen the sedimentary type REE deposits in the Mazha area, Weining County, Guizhou Province as the research object, and have studied the elemental composition, mineral composition and the REE occurrence state of ores by using the XRF analysis, ICP-MS analysis, X-ray diffraction analysis, scanning electron microscopy and energy spectrum analysis, electron probe analysis, phase analysis and other means. The results show that the REE ore is mainly composed of Al, Si, Fe, K and Ti. It contains total amount of the REE (REO) varying from 1064×10-6 to 14106×10-6. Its REE distribution patterns are characterized with the LREE enrichment and the HREE depletion. Minerals of the ore can be classified into silicate minerals (mainly kaolinite, illite), metal oxide minerals (mainly limonite, anatase, rutile, etc.), carbonate minerals, and the REE minerals. The REE in the ore occurred in the form of nano-scale independent minerals which are speculated to be florncite and cerianite based on their compositions. At the same time, the REE also occurred in the form of isomorphism in clay minerals, or occurred occasionally in the form of ion adsorption.
Keywords: sedimentary type REE deposit; occurrence state; nano-scale independent minerals; the Mazha REE deposit; the northwestern Guizhou
