Investigation of mineralogical, petrographical and geochemical properties of sedimentary unit in Kaleboğazi Eocene basin (Amasya)

The Kaleboğazı Eocene Basin has an asymmetrical depression basin with a faulted southern border. The metamorphics of the Paleozoic aged Tokat Massif in the south and east of the basin and the Karakaya formation represented by Triassic aged clastic, carbonated, volcanite rocks, spreads in the southwest. In the north, the carbonate rocks of the Jura-Cretaceous aged Bilecik Limestone and Sogukcam Formation are exposed. The Middle Eocene aged Yoncalı Formation, which consists of turbiditic marl, siltstone, mudstone and sandstone, unconformably overlies this basement. Middle-Upper Eocene aged Beynamaz Volcanics containing basaltic andesite, lava, tuff, and agglomerate overlie the Yoncalı Formation and Middle-Upper Eocene aged Beynamaz Volcanics containing basaltic andesite, lava, tuff and agglomerate overlie the Yoncalı Formation and crop out in large areas in the south of the study area. In the upper part of the sequence, Quaternary aged units and lacustrine sediments belonging to Late Miocene-Pliocene aged Yedikır Formation consisting of conglomerate, sandstone, mudstone and marl are observed. Four deep drillings were made by TKI in the study area. The depth of the drillings varies between 420m and 750m. In the drillings, coal seams of 10cm and 20cm thickness were cut in several levels. Clay minerals, feldspar, quartz, calcite, dolomite, gypsum, anhydrite and pyrite were determined by XRD studies. Smectite, illite and kaolinite were identified from clay minerals. SiO2 and Al2O3 contents generally increase at clayey levels. Ca2+ ions are the main components of carbonate and sulfate rocks. It was determined that the samples were formed under humid, semi-dry conditions by sedimentation process and the origin rock was locally basic and mostly acidic.