Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9953646 | International Journal of Coal Geology | 2018 | 133 Pages |
Abstract
The anthracites from the two deposits are medium- to high-sulfur coals. The rare earth elements in the Luocheng anthracites are characterized by distinct positive Eu anomalies and medium- and heavy-REE enrichment types. The minerals in the Hongmao anthracites are characterized by the occurrence of K-illite, paragonite, and ammonian illite, which, however, are absent in the Luocheng anthracites. The paragonite, ammonian illite, and chlorite resulted from the alteration of pre-existing kaolinite by hot solutions containing Na+, NH4+, and Fe2+ respectively. The partings in the Luocheng anthracite seams contain pyrophyllite that was formed by reactions between kaolinite and quartz during injection of high-temperature solutions. The mineralogical and geochemical characteristics of the anthracites in the two deposits indicate that the coals were subjected to high-temperature (>250â¯Â°C) solutions that also elevated the coal rank to anthracite grade. The assemblage of K-illite-paragonite-NH4-illite in the coals of the Hongmao deposit was formed under greater hydrothermal but less tectonic influence compared to the Luocheng deposit; by contrast, the pyrophyllite-illite-chlorite assemblage of the Luocheng deposit reflects a greater tectonic but lesser hydrothermal influence.
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Authors
Shifeng Dai, Dongping Ji, Colin R. Ward, David French, James C. Hower, Xiaoyun Yan, Qiang Wei,