Lutetian-Bartonian (Middle Eocene) micropalaeontology, biostratigraphy and palaeoecology of the Mengen Coal Basin, Northwest Turkiye (Turkey)

This study focuses on the upper Lutetian-lower Bartonian Tokmaklar Formation in the Mengen Basin of Northwest Turkiye (Turkey), examining various aspects such as biostratigraphy, palaeoecology, and isotope data (S18O and S13C), providing insights into the geological history and environmental conditions during this interval. Moreover, the study incorporates coal petrography on four samples to explore a potential correlation between the coalification process and the preservation of palynomorphs. The formation is informally divided into two distinct categories: a coal-bearing sequence positioned at the base of the formation and a coal-free sequence above it. However due to dense vegetation and soil cover in the area, the availability of suitable outcrops for measured sections and obtaining samples is severely limited. Therefore, we relied on drilling data from Turkish Coal Enterprises (TCE) for the purpose of coal exploration, as well as two partial sections (Ender and C,orak) from underground mining. Microapalaeontological evidences involving benthic foraminiferans, ostracods, and palynomorphs, along with isotope data (S18O and S13C), suggest that the Tokmaklar Formation was deposited as a result of a local transgressive process during the late Lutetian-early Bartonian. Furthermore, palynological data, particularly the existence of mangroves such as Nypa, lepidocaryoid palm and Acrostichum aureum, coupled with quantitative palaeoclimate analysis, the negative S18O values, and the lower S13C values indicate a warm, probably tropical climate under high rainfall. (c) 2024 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.