Organic maturation and maceral associations of oligocene sedimentary rocks from eastern denİzlİ, Turkey

Abstract

The study area is located 80 km east of Denizli province. Sedimentary units in the study area are composed of conglomerate, sandstone, and mudstone containing coal. The aim of this study was to assess the thermal maturation and maceral associations of organic matter rich rocks from Hayrettin Formation by using organic geochemical and organic petrographic analysis. The total organic carbon (TOC, %) contents of sedimentary rocks range from 2.12 wt.% to 34.35 wt.%, and hydrogen index (HI) values are between 25 mg HC/g rock and 146 mg HC/g rock. Studied samples predominantly contain Type III kerogen (woody organic matter). Tmax and production index (PI) values of organic matter rich rocks range from 404oC – 433oC and 0.01 – 0.07, respectively. Based on organic petrographic data from three samples (BHY-2, BHY-3 and BHY-5) huminite maceral group (especially ulminite macerals) ranges from %29.2 to %65.7, liptinite maceral group ranges from %0.6 to %2.4 and finally inertinite maceral group ranges from %0.2 to %0.8. Huminite/vitrinite reflectance (Vr%) values of these three samples are 0.45%, 0.43% and 0.42%, respectively. According to organic geochemical and organic petrographic data, the organic matter rich rocks have excellent gas hydrocarbon potential but those samples are in the thermally immature stage. High amounts of ulminite in the organic matter rich rocks from Hayrettin Formation may indicate that these samples are deposited under low pH conditions within forested wet raised bogs. Vr% values of investigated samples are indicating sub-bituminous B rank or brown coal stages. © SGEM2018.