大同煤田王坪井田太原组8号煤层煤相特征

Taiyuan Formation Coal Seam No.8 Coal Facies Features in Wangping Minefield, Datong Coalfield

以大同煤田王坪井田太原组8号煤层为研究对象,采用光学显微镜、煤质分析、电感耦合等离子质谱(ICPMS)和X射线荧光光谱(XRF)等方法探讨了其煤岩学、煤质和煤地球化学特征,并在此基础上分析了其煤相特征。结果表明:(1)王坪井田太原组8号煤层宏观煤岩类型为半亮煤和半暗煤,显微组分以镜质组和惰质组为主,显微煤岩类型为微暗亮煤和微亮暗煤;(2)8号煤为低水、中低灰、中低硫和中高挥发分气煤;(3)煤层顶部和底部属于陆相-过渡相,其余分层为海相-过渡相;(4)成煤环境为三角洲平原的泛滥盆地,煤相基本为开阔水域沼泽相,部分为湿地草本沼泽相;煤层自下而上经历了水位升降两个过程,并由于水位过深发生一次煤层聚集间断,反映了沼泽环境及成煤植物的演化规律。

Taking the Taiyuan Formation coal seam No.8 in Wangping minefield, Datong coalfield as subject investigated, using optical microscopic, coal quality analysis, inductively coupled plasma mass spectrometry（ICP- MS） and X- ray fluorescence spectrometry（XRF） methods carried out studies on coal petrology, coal quality and coal geochemical characteristics, on these bases analyzed coal facies features. The result has shown： 1） Macrolithotype of Taiyuan Formation coal seam No.8 in Wangping minefield is semibright coal and semidull coal, macerals have mainly vitrinite and inertinite, microlithotypes have durite and clarite. 2） Coal seam No.8 is low moisture, medium low ash, medium low sulfur and medium high volatile matter gas coal. 3） Coal seam top and bottom parts belong to terrestrial-transitional facies; other slices marine-transitional facies. 4） Coal-forming environment was delta plain flood basin, coal facies were basically open water bog facies, part wet land herbal bog facies; coal seams experienced water level rising and falling two courses,meanwhile since an interrupt of coal accumulation happened, thus reflected on bog environment and coal-forming plants evolutional pattern.