Abstract:Taking the Jurassic Yanan Formation (Fm.) coal from the southern foot of Xiangshan in Ningxia as the research object to study the geochemistry characteristics of rare earth elements (REE) and discussed its occurrence characteristics and geological implications based on the data from X-ray fluorescence spectrometer and plasma mass spectrometer. The results indicate that the coal in the study area is non-caking coal characterized by low ash content, medium to high volatile matter and high calorific value. CaO, MgO and P<sub>2</sub>O<sub>5</sub> are significantly enriched relative to coals in China, with enrichment factors of 1.82, 4.14 and 2.07, respectively. The average total REE content is 63.49 μg/g, which is considerably lower than the average value of Chinese coals (139 μg/g) and slightly higher than that of global coals (60.7 μg/g). The coal displays a REE distribution pattern with relative enrichment of light rare earth elements (LREE) (average LREE/HREE = 8.11), higher fractionation degree of heavy rare earth elements (HREE) than LREE (average Gd?/Lu? = 1.73), and distinct positive Eu anomalies (average δEu = 1.95). Correlation analysis and principal component analysis suggest that REE mainly occur in aluminosilicate clay minerals and titanium-bearing clay minerals, with terrigenous clastic input as the dominant material source. On the basis of REE geochemical parameters, Al<sub>2</sub>O<sub>3</sub>-TiO<sub>2</sub> provenance discrimination diagrams and multi-index collaborative analysis, it is revealed that the Yan"an Formation coal in the study area was formed in a reducing peat swamp environment with acidic water media under cold and arid climatic conditions. The provenance is dominated by intermediate rocks mixed with felsic components, and the inheritance of source rocks dominates the core geochemical characteristics of REE.