Bozcu, Ayşe2025-01-272025-01-2720171300-09851303-619Xhttps://search.trdizin.gov.tr/tr/yayin/detay/244133https://hdl.handle.net/20.500.12428/19518The Lower-Middle Miocene Küçükkuyu Formation crops out extensively in the Edremit Gulf area (NW Turkey). In thisstudy, shale samples from this unit were investigated to evaluate source rock characteristics, depositional conditions, and hydrocarbonpotential. Outcrop samples of the Küçükkuyu Formation were taken from different locations and analyzed by Rock-Eval pyrolysis,vitrinite reflectance (R o ), stable carbon isotope (δ 13 C), total sulfur (TS), gas chromatography (GC), and gas chromatography-massspectrometry (GC-MS). The total organic carbon (TOC) values range from 0.23 to 6.1 wt.% with an average of 1.76 wt.% for thenorthern samples and 0.24 to 2.82 wt.% with an average of 1.66 wt.% for the southern samples around the Edremit Gulf. Hydrogen index(HI) values were up to 606 and 712 mg HC/g TOC in the north and south of the gulf, respectively. Organic matter type in the formationconsists predominantly of Type II and III kerogen with a minor component of Type I kerogen. Tmax values ranging from 414 to 496 °Cin the north and 423 to 446 °C in the south of the gulf indicate that most samples are at the beginning of the oil generation window andare thermally immature or early-mid-mature. Vitrinite reflectance (R o ) and biomarker maturity parameters support this result. Basedon geological observations, biomarker distributions, and TOC/TS ratios, the Küçükkuyu Formation was deposited in a freshwater toslightly brackish water environment under anoxic-suboxic conditions with organic matter input from aquatic organisms and fromterrestrial higher plants. According to Rock-Eval pyrolysis data, the Küçükkuyu Formation mostly has medium to good hydrocarbon- generation potential. However, as these potential source rocks are in general immature and/or early-mature, the hydrocarbon potentialof the study area is very limited.eninfo:eu-repo/semantics/openAccessMühendislikJeolojiKimyaUygulamalıJeolojiArticle265354376244133