Maceral and Organic Geochemical Characteristics of the Late Permian Coals from Yueliangtian Mine, Guizhou, Southwestern China

Abstract

Compositional characteristics of maceral and extractable organic matter (EOM) of the No. 10 coal from the Yueliangtian mine, Guizhou, Southwestern China, were analyzed by optical microscopy, gas chromatography (GC), and gas chromatography-mass spectrometry (GC-MS). The depositional conditions, thermodynamic effect, type and maturity of organic matter, and possible health hazards were evaluated. The random vitrinite reflectance (R o ) is 1.01%, and the macerals are dominated by collodetrinite, inertodetrinite, collotelinite, and fusinite. The coal seam is a terrestrial sedimentary environment of the lower delta plain through the analysis of coal facies. Additionally, the extracted yield of EOM is 1.01%. The low ratio of saturated to aromatic fraction and the distribution of n-alkanes indicate that the coal-forming plants are primarily terrestrial higher plants. Typical isoprenoid biomarker parameters, including pristane/phytane (Pr/ Ph), Pr/n-C 17 , and Ph/n-C 18 , reflect a weak oxidizing environment of coal. The hopanoid biomarkers, odd−even predominance index (OEP), and carbon preference index (CPI) reveal that the organic matter was mature. More than one hundred polycyclic aromatic compounds (PACs) were eluted and identified, and the phenanthrenes and naphthalenes account for a higher proportion. Thermodynamic stabilities play an essential role in the conversion of molecular structures, which support the relatively high contents of 2-methylnaphthalene, 2-and 3-methylphenanthrenes, and 2,6-and 2,7-dimethylphenanthrenes compared to their respective isomers. The oxygen-containing and sulfur-containing aromatic compounds also indicate the weak oxidization of the coal-formation environment, which is consistent with the results of isoprenoid biomarkers. Because of the carcinogenicity and mutagenicity of PACs, the distribution and toxic equivalency of PACs are briefly summarized.

Mineralogy and Geochemistry of High-Sulfur Coals from the M8 Coal Seam, Shihao Mine, Songzao Coalfield, Chongqing, Southwestern China

“…The Late Permian coal in Southwestern China is one of the research topics of interest, attributed to its large reserve of 75 bt occupying 3% of the total coal reserves (depth of reserve calculation less than 1000 m) in China [10,19,20]. In this region, the enrichments of economically important elements including Nb, Ta, and Zr in the Zhina, Liuzhi, Huayingshan, Nantong, and Moxinpo Coalfields [16,[21][22][23][24], and U, Mo, and V in the Guiding Coalfield [25], have been universally discovered.…”

Determination of Polycyclic Aromatic Hydrocarbons in Coal from the Kuznetsk Coal Basin by Means of GC/MS and GC/GC-FID

“…The characteristics of the maceral composition of the extractable organic matter in coal from the Yueliangtian mine in Guizhou, Southwestern China, were analyzed using optical microscopy, gas chromatography (GC), and gas chromatography-mass spectrometry (GC-MS) [8]. Extraction was performed with methylene chloride in a Soxhlet apparatus for 36 h, and the yield of the organic matter was 1.01%.…”

“…More than 100 compounds of PAHs class were elutriated and identified, with phenanthrenes and naphthalenes comprising the major fraction. Thermodynamic stability plays an essential part in the transformations of molecular structures during coal formation, so relatively high concentrations of 2-methylnaphthalene, 2-and 3-methylphenanthrenes, 2,6-and 2,7-dimethylphenanthrenes in comparison with their corresponding isomers are detected in the extracts [8].…”

Organic geochemistry and petrology of the coals in the Laisong Formation, Naga Schuppen Belt, NE India: Inferences on hydrocarbon potential and depositional environment

“…The maceral composition of coal and the physicochemical properties of the individual macerals are a function of a complex mixture of factors, including the type of precursor plants, sedimentary environment and its settings, microbial activity, etc. (Lu, Qin, Xu, Chang, & Wang, 2021). The macerals are classified into three groups and generally studied by following the system framed by the International Committee for Coal Petrography (ICCP, 1998(ICCP, , 2001Pickel et al, 2017;Sýkorová et al, 2005).…”