Geochemical Characteristics of REE in Jurassic Coal of Yan' an Formation from Dongsheng Coalfield

摘要

Concentrations of rare earth elements (REE) in Jurassic coal of YanAn Formation from Dongsheng coalfield located in the northeast of Ordos basin were determined by instrumental neutron activation analysis (INAA). Curves of distribution pattern of REE were drawn, and many geochemical parameters were calculated. The result shows that The contents of REE in Jurassic coal with low ash and sulfur are lower than those of Carboniferous and Permian coal from the Basin of North China; Inside the Dongsheng coalfield, coal from the north has higher contents of REE than that form the south because the north is near the area of source rock which is the main supplier of REE, while the south is far away from the area of source rocks; Although Jurassic coal in Dongsheng is the low-ash coal with less than 10% , the contents of REE are still proportional to ash yield of ash and SiO2 contents.Although the Jurassic coal in Dongsheng were deposited in ox-idative continental environment of river-lake, Eu depletion of REE in coal commonly exists, and positive abnormity of Ce dose not exist. This reflects the REE distribution pattern of REE in source rock of continental area; and Compared with other rocks, coal shows extremely complexity of distribution pattern of REE, which is the result of continuous alteration and redistribution of matter in coal occurred in open basin system.