Optical anisotropy of coal from the Ruda syncline area in the upper Silesian Coal Basin (USCB) and its relation to tectonic setting


Authors: Morga R, Probierz K

Published in: Bulletin of Geosciences, volume 74, issue 2; pages: 159 - 162;

Keywords: Upper Silesian Coal Basin, tectonics, coalification, optical anisotropy, bireflectance, indicatrix,

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Oriented blocks and non-oriented samples were examined. True reflectance values determined on the oriented blocks are Rmax = 0.94-1.02 %, Rint = 0.88-0.95 % and Rmin = 0.81-0.86 % whereas on the non-oriented samples: Rbmax = 0.96 - 1.03 %, Rbint = 0.90-0.96 % and Rbmin = 0.83-0.88 %. Bireflectance amounts analogically: Rbi = 0.12=0.17 % and Rbbi = 0.13-0.15 %. Vitrinite in all the cases reveals biaxial negative optical character. Direction of Rmax axis (azimuth 18°-38°) is concordant with the syncline axis. Deviation of Rmin axis from the vertical is usually 10-15° with SE plunge and its reorientation from perpendicular to bedding reaches 8-20°. Coalification in the study area occurred simultaneously with the formation of the Ruda syncline. Vitrinite indicatrix was formed by stress connected mostly with occurrence of the overburden or movements of the crystalline basement blocks but also due to the East-Sudetic compression.