Organic geochemistry and trace element distribution of şarki̇karaağaç (Isparta) coals

The investigated area is located Şarkikaraağaç (Isparta-Turkey). The Neogene units in the basin consist of conglomerate, sandstone, siltstone, mudstone, claystone, coal, marl and limestone. The coaly unit, unconformably overlies pre-Neogene units including metamorphic rocks, ophiolites and carbonates. The purpose of this work is to characterize the organic geochemistry, organic petrography and trace element distribution of the Neogene coaly rocks of the Şarkikarağaç basin. Total organic carbon (TOC) values are between 10.19-47.05 %, hydogen index (HI) values vary between 73-292 mg HC/g TOC and Tmax values vary between 398-443 °C. Kerogen in the deposits is type III, as indicated by organic petrographic observations and Rock-Eval data. Facies C and CD was determined according to the organic facies evaluation. Organic matter is composed predominantly of woody material, with a minor contribution of planty and coaly material. Huminite reflectances measured on the coal samples between 0.28-0.29 %Ro and it shows that immaturity stage. These values indicate that coal rank can be classified as lignite (soft brown coal). Huminite is the most abundant maceral group (38-91 %). Small amounts of liptinite (2-55 %) and inertinite (5-23 %) are observed within the coals. According to the maseal analysis, the coals are formed in limnic to limno-telmatic, marsh zone. Calcite, quartz, pyrite, feldspar minerals, plagioclase minerals, mica minerals, gypsum, dolomite, aragonite, cristobalite, siderite, ankerite, analcime, clay minerals except for amorphous matters were determined in the coal samples with XRD. Clay minerals identified in the basin were illite, smectite, kaolinite and chlorite. According to the major-trace element evaluations, Mg, Ca, P and for trace elements, like Ni, Sc, Co, Cs, Hf, Sr, U, V, W, Cu, Pb, As, Ag, Se elements were enriched in study area. Element enrichment in the basin is mostly of inorganic origin. As results of geochemical parameters show that the deposition environments indicate more anoxic redox conditions with less disoxic conditions.