Organic geochemical characteristics and depositional environment of Late Miocene aged Honaz (Denizli) coal series

Abstract

In this study, paleo depositional environment was determined by examining the organic petrographic and organic geochemical characteristics of Upper Miocene coal series from Honaz-Kocapinar (Denizli). Total organic carbon amounts of investigated samples range from 5.51 to 51.80 wt. % (on average 23.66 wt. %). Average HI and Tmax values are respectively, 71 mg HC/g TOC and 410 degrees C. According to results of pyrolysis analysis, coal series contain Type III kerogen. The organic fraction of the samples is comprised of huminite and liptinite group macerals. Very low huminite/vitrinite reflection, Tmax values and Ts/Ts+Tm, Ts/Tm, C-30 Moretane/C-30 Hopane ratios, beta beta/(alpha alpha+beta beta) C-29 and C-28 isomers and 20S/(20R+20S) sterane ratios indicated that immature organic matter. Long-chain n-alkanes are dominant peaks and carbon preference index (CPI), terrestrial/aquatic ratio (TAR), degree of waxiness and C-29 Ts/(C-29 Ts + C-29 Norhopane) ratio indicates that terrestrial high plants. Pyrolysis analysis, maceral determination and biomarker data showed that Honaz-Kocapinar (Denizli) coal series in thermally immature stage, containing predominantly terrestrial organic matter and deposited sub-oxic conditions.