QUALITY VARIATIONS IN THE HIGH-SULFUR LIGNITE OF THE NEOGENE BEYPAZARI BASIN, CENTRAL ANATOLIA, TURKEY

During the Miocene a number of fault bounded basins developed in Centr al Anatolia, Turkey. One such basin at Cayirhan, near Beypazari, conta ins thick, laterally extensive lignite seams. This basin was filled in itially with coarse elastic material. Upward fining of the clastics du ring basin fill, with an increase in the amount of clay and carbon con tent led to the development of relatively shallow limnic basins in whi ch extensive peat deposits accumulated in low-lying mires. These ligni tes are characterized by their high sulphur and ash contents (up to 8. 2% S and 68.3% ash on an air-dried basis). Studies of the sulphur and ash contents reveal three types of distribution; namely, vertical vari ation within individual seams, variation between the seams and lateral variation across the basin. In the case of the sulphur content, verti cal variation within and between the seams is related to variations in the amount and source of the sulphate in the mire water, and the late ral variation is probably related to structural/topographic control of the mire at the time of formation. Variation in the ash content withi n the seams is probably the result of depositional processes at the ti me of mire development. Variation between seams is recognized due to t he presence of ubiquitous zeolites in the mineral matter; namely heula ndite in the first seam and analcime in the second seam. This is proba bly the result of variations in the chemistry of the original volcanoc lastic or clastic material associated with the lignite or of variation s in the chemistry of the circulating fluid. There is a broad east-wes t lateral variation across the basin in the ash content of the seams, probably resulting from variations in the amount and rate of elastic o r volcanoclastic influx into the mire at the time of formation, relate d to structural/topographic controls.