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Geoscience ›› 2025, Vol. 39 ›› Issue (03): 612-627.DOI: 10.19657/j.geoscience.1000-8527.2024.131

• Machine Learning and Its Applications in Mineralogy • Previous Articles     Next Articles

Genetic Study of Weishan Rare Earth Deposit in Shandong Province: Constraints of Rare Earth Mineralogy

LAN Jun1,2(), LIU Xiao1,*(), ZHANG Peng2,3, XING Nan2,3, LI Zhimin2,3, LI Jian1, XU Hongyan2,3, LAN Tingguang4, WANG Shi2,3, WANG Jian2,3   

  1. 1. Shandong University of Technology School of Resources and Environmental Engineering, Zibo, Shandong 255000, China
    2. Shandong Fifth Institute of Geology and Mineral Exploration, Taian, Shandong 271000, China
    3. Academician Workstation for Research and Exploration of Rare Earth Mineralization in Shandong Province, Taian, Shandong 271000, China
    4. Institute of Geochemistry Chinese Academy of Sciences, Guiyang, Guizhou 550081, China
  • Online:2025-06-10 Published:2025-07-03
  • Contact: LIU Xiao

Abstract:

The Weishan rare earth element (REE) deposit in Shandong is located in the Laiwu-Zibo-Weishan REE belt in the eastern part of the North China Craton and is one of the three major light REE deposits in China. To better investigate the migration and enrichment processes of REEs, this study conducted detailed mineralogical research on the Weishan deposit. Based on the mineral paragenesis and cross-cutting relationships between veins, the hydrothermal mineralization of the Weishan rare earth deposit was divided into four stages: (Ⅰ) K-feldspar+quartz+calcite, (Ⅱ) sulfate+quartz+calcite, (Ⅲ) REE minerals+quartz+calcite+sulfate+fluorite, and (Ⅳ) calcite+quartz+fluorite+sulfides. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and electron probe microanalysis (EPMA) of each mineralization stage revealed that the main REE minerals are bastnäsite, parisite, strontianite-(Ce), and minor monazite, (Ce) apatite, and thorite. Additionally, these REE minerals are closely associated with fluorite, calcite, and sulfate minerals, indicating that the ore-forming fluid was likely a H2O-CO2-NaCl-F-REE- S O 4 2 - hydrothermal system. During the mineralization process, ions such as F-, Cl-, C O 3 2 -, and S O 4 2 - contributed to varying degrees to the migration and enrichment of key ore-forming elements. Considering the regional tectonic background, this paper proposes that the Weishan REE deposit formed under the tectonic regime of the rollback of the subducting Paleo-Pacific Plate, with the complex late-stage differentiation of crust-mantle mixed magma and associated ore-forming fluids playing a key role in the mineralization process.

Key words: mineral assemblage, ore-forming fluids, ore genesis, mineralization model, Weishan rare earthdeposit

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