The Late Permian coals from the Huayingshan Coalfield of southwestern China are significantly enriched in Zr (695. μg/g), Nb (75.9. μg/g), Se (6.99. μg/g), Hf (10.1. μg/g), and rare earth elements and Y (1423. μg/g). Previous studies showed that the sediment-source region for these coals was the Kangdian Upland, which was formed at an early stage of the late Permian Period. The source rocks have a basalt composition, and those studies attributed the enrichment of the above high field strength elements (HFSEs) to derivation from the Kangdian Upland.Geochemical and mineralogical data presented in this study show that the dominant sediment-source regions for the coal and roof strata of the Huayingshan Coalfields are the Dabashan Uplift, Hannan Upland, and Leshan-Longnvsi Uplift. The highly-elevated concentrations of HFSEs in the coals are due to hydrothermal fluids. Three tonstein layers derived from alkali rhyolite were identified. These tonsteins are characterized by highly-enriched HFSEs and by strong negative Eu anomalies in the rare earth element distribution patterns.The major carriers of the rare earth elements in the coal are rhabdophane and silicorhabdophane, the latter of which is also enriched in Zr. Zirconium, however, mainly occurs in zircon. Rhabdophane and silicorhabdophane in the coal are mainly distributed along the bedding planes and occur as cell-fillings. Zircon in the coal occurs as cell-fillings and is of authigenic origin. Anatase in the partings and coals contains Nb, and occurs as fracture-filling and colloidal forms. The modes of occurrence of the above minerals indicate that they were derived from hydrothermal fluids. Mercury and Se mainly occur in sulfide minerals (pyrite and marcasite).
|Number of pages||19|
|Journal||International Journal of Coal Geology|
|State||Published - Feb 1 2014|
Bibliographical noteFunding Information:
This research was supported by the National Key Basic Research Program of China (no. 2014CB238902 ), the National Natural Science Foundation of China (nos. 41272182 and 40930420 ), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT 13099 ). Many thanks are given to Mr. Michael Trippi from USGS who helped with generation of the GIS image for the coalfield distribution in China.
- Hydrothermal fluid
- Late Permian coal
- Minerals in coal
- Terrigenous material
- Trace elements in coal
- Volcanic ash
ASJC Scopus subject areas
- Fuel Technology
- Economic Geology