MINERALOGY AND PETROGRAPHY OF THE 2 LOWER EOCENE LACUSTRINE COALS, SORGUN AND SULUOVA, TURKEY

Coal reserves of Lower Eocene age are limited in Turkey and the most i mportant are situated in the Sorgun and Suluova basins. A thick and la terally extensive coal seam occurs at the base of the Celtek Formation in the two basins. The Celtek Formation was developed in a fluvial-la custrine facies and was unconformably overlain by transgressive units of Middle-Upper Eocene age. The coal samples were studied mineralogica lly and petrographically, and to define fluorescence emission spectra of sporinite and cutinite. A total of 75 coal samples collected from t he two basins are characterized, on an air-dried basis, by relatively low moisture contents (0.69-9.31 wt%, av. 3.90 wt%), a broad range of ash yields (2.4-67.8 wt%, av. 19.9 wt%), total sulphur contents (0.55- 7.60 wt%, av. 2.15 wt%), and calorific values (1689-7480 kcal/kg, av. 5458 kcal/kg). Minerals of the coals from the two basins determined on an air-dried basis by X-ray diffraction method are mainly kaolinite, quartz and pyrite. Kaolinite and pyrite contents of the Sorgun coals a re higher and quartz contents are lower than those of the Suluova coal s. In addition, a few samples in the Sorgun coals contain epigenetic c alcite, whereas some samples in the Suluova coals contain syngenetic s iderite, calcite and dolomite. The coals in general are characterized by high contents of macerals of the huminite group (av. 69.0 vol%), an d contain liptinite (av. 4.9 vol%), inertinite (av. 0.8 vol%) and mine ral matter (av. 25.3 vol%). On the TPI and GI diagram the coals plot i n the limno-telmatic and telmatic areas in which the Sorgun and Suluov a peats accumulated between the high and low water tables. Fluorescenc e emission spectra of sporinite and cutinite macerals are, in general, similar in the coals of both basins, but the spectral maxima of spori nites and cutinites are between 594-658 nm and 592-671 nm respectively . The values for the sporinites indicate a relatively broad range of c oal rank. However, the range of values of the mean random ulminite (ma inly eu-ulminite A) reflectances (0.46-0.60%Rr, av. 0.53%Rr), the prox imate and ultimate analyses imply that the rank is a subbituminous A c oal transitional to high-volatile C bituminous coal according to the A STM classification. (C) 1997 Elsevier Science B.V.