Organic geochemical and isotopic (C and N) characterization of carbonaceous rocks of the Denizli Area, Western Turkey

The sediments under examination constitute part of the Hayrettin Formation expanding to the northwest of Augol (Denizli/Turkey) containing coal. The aims of this study are to assess the organic matter content (Corg, %), type, maturity and established paleoenvironment of deposition based primarily on Rock-Eval pyrolysis data, biomarker distributions and delta C-13, delta N-15 values. The total organic carbon (Corg, %) contents of carbonaceous rocks range from 0.21% to 39.61%, and hydrogen index (HI) values are between 25 and 174 mg HC/g rock. The samples studied contain type III organic matter (OM). T-max values for the Hayrettin carbonaceous rocks range from 400 to 437 degrees C. Vitrinite reflectance values (Ro) are between 0.26% and 0.36%, and these values reveal that the carbonaceous rocks are at peat-lignite coal stage. On the basis of biomarker maturity parameters, these rocks are immature. The high pristane/phytane (Pr/Ph) ratios (0.79-7.85), low C-35 homohopane index (0.02-0.07) indicates that carbonaceous rocks were deposited in a suboxic environment. delta C-13 (range from -26.06 parts per thousand to -23.88 parts per thousand) and delta N-15 (range from 2.63 parts per thousand to 3.33 parts per thousand) values, high concentrations of C-29 steranes (C29 > C28 > C27) and C-26/C-25 tricyclic terpane ratios (1.00 and 1.18) indicate that these carbonaceous rocks formed in a peat-swamp environment. (C) 2014 Elsevier B.V. All rights reserved.