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    GEOCHEMISTRY OF OLIGO-MIOCENE COALS IN GELIBOLU PENINSULA, NW TURKEY
    (Stef92 Technology Ltd, 2014) Demirtas, Ferdi; Kosun, Erdal; Bozcu, Mustafa
    The concentrations and distributions of major and trace elements, including potentially hazardous trace elements, in coals from two coal beds in Gelibolu Peninsula, NW Turkey, have been determined in this study. Coal-bearing sequences are located in Oligocene and Miocene formations. Major and trace element concentrations of the thirteen coal samples were determined by inductively coupled-plasma mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). In order to determine the enrichment of trace elements, comparisons are made to Turkey and world coals. Si, Al and Fe are the most abundant elements detected in the both coal seams. They are probably associated with clay minerals, quartz and pyrite. The most abundant trace elements are Ba and Sr with an average concentration of 209 ppm and 162.1 ppm, respectively, followed by As, Ni and Zr, which have average concentrations above 50 ppm. The remaining elements have average concentrations below 50 ppm. Some of the potentially hazardous trace elements including As, Ni, Th, and V have concentrations higher than the range of world coal averages. Compared to two coal seams (Oligocene and Miocene), they have similar concentration of trace elements, however, Zn, Ni, Y, Cs and Rb are more abundant in Oligocene coals, whereas, As, U, Mo, and W are more abundant in Miocene coals.
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    Petrography and palynology of Late Oligocene and Middle Miocene coals in the Gelibolu peninsula, NW Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2015) Demirtas, Ferdi; Bozcu, Mustafa; Kosun, Erdal; Akkiraz, Mehmet Serkan
    In this study, coal samples from two different coal zones located close to each other were examined. They occur in the Late Oligocene Osmancik and Miocene Gazhanedere formations in the Gelibolu peninsula, in the SW part of the Thrace Basin (NW Turkey). This paper focuses on the organic-petrographic composition and depositional conditions of the two coal zones by using coal petrography, including maceral ratios, and palynology. The maceral composition of the Oligocene coal samples is similar to that of the Miocene coal samples. The coal samples from both locations are characterized by a high content of huminite group macerals, ranging from 46% to 78%. The prevailing maceral from this group is gelinite (31%-65%), which is indicative of a high degree of gelification of organic matter. Relatively low contents of liptinite (not exceeding 9%) and inertinite (not exceeding 8%) were also determined. The tissue preservation of organic matter was poor. The content of mineral matter is inferred from microscopic studies and is variable but generally high, varying from 6% to 46%, similar to that of other Turkish coals; it consists mostly of quartz, calcite, clay minerals, and pyrite. This input of mineral matter is probably related to periodic inundations of swamp. The mean reflectance values of samples ranged from 0.42% to 0.50% Ro, suggesting that the rank of coal is subbituminous according to ASTM classification. Low tissue preservation index (TPI) and high gelification index values suggest that both coal zones were deposited in a limnic environment. The presence of framboidal pyrite and low TPI reflect high pH values (pH 6-7) and reducing conditions during peat deposition. Two different palynological assemblages may be distinguished based on the percentages of palynomorphs. The first assemblage including the stratigraphical marker species Dicolpopollis kockelii (Calamus) suggests the Late Oligocene. The age of the second assemblage is probably the end of Middle Miocene.