Sedimentological and Petrographical Characteristics of Coal- and Oil Shale-Bearing Strata from the Ilisilik Region, Central Anatolia, Turkey

摘要

The present study describes the sedimentology, coal petrology, and geochemistry of a Miocene coal- and oil shale-bearing succession in the Ilisilik region in central Anatolia, Turkey. Vertical sequence analysis within the 50-150 m thick coarse-grained succession of the Ihsihk oil shale field has allowed 4 sedimentary associations to be distinguished. The fades associations in the Ihsihk oil shale field are dominated by fluvial deposits, which document abrupt fades transitions along the axis of the basin. Fluvial poorly-sorted cobble conglomerates of fades association 1, located along the basin margin grade basinward into well-sorted conglomerates of fades association 2. These deposits grade basinward into the laterally continuous sheets of trough cross-bedded fine-grained sandstone and massive siltstone of fades association 3. Further basinward the fine elastics, oil shale, and coal of fades association 4 are common. Reflectances measured on vitrinite are between 0.54 and 0.67% Rmax. This indicates a coalification equivalent to low volatile subbituminous coal rank of the American Society for Testing and Materials classification for the Ihsihk coals. The maceral composition makes the Ihsihk oil shales of the lamosite type.