INTRODUCTION TO THE PETROLOGY AND INFRARED-SPECTRA OF SHANXI COALS, PEOPLES-REPUBLIC-OF-CHINA

Twelve samples of coal from the three major depositional episodes whic h occurred on the North China Block during the Carboniferous, Permian and Jurassic Periods have been investigated. The samples varied in ran k from high volatile bituminous coal to anthracite and, although the c oals from the three sequences were formed from different plants under different climates, plots of random vitrinite reflectance against elem ental H/C ratios were similar to those previously reported from coals deposited in Euramerica and Gondwanaland. None of the samples which ha ve been examined contained significant quantities of liptinite; the vi trinite consisted mainly of desmocollinite. Shanxi coals resemble petr ologically those from Gondwanaland. Diffuse reflectance, Fourier trans form infrared (FT-i.r.) spectra of twelve samples and of their residue s after pyridine extraction are presented and the chemical structures of these vitrinite-inertinite coals are shown to be very similar to th ose of better known bituminous coals. Increasing maturity (rank) of th e coals can be attributed to increase in the geothermal temperature to which they have been subjected and is accompanied by the expected inc rease in aromaticity and also by an increase in the protonation of the aromatic structures. The spectra suggest that vitrinite-inertinite ri ch coals from many different depositional settings have similar patter ns of substitution around their aromatic rings, the similarity increas ing with rank. Thus the chemistry of vitrinite-rich coals appears to b e controlled by the possession of common hydroaromatic structures.