The sedimentary basins in SW Turkey (e.g., Kale-Tavas, Yatagan, and Oren basins) that developed after the closure of the Neotethys Ocean allow the reconstruction of the tectonic and paleogeographic history of the region. Due to the rich coal reserves, the Yatagan Basin provides a substantial amount of data to infer the paleoenvironment and paleocllinate during the middle Miocene to Pleistocene. Our work provides new paleontological and radiometric data to constrain the age, paleoclimate, and depositional environment of terrestrial deposits of this basin. We present fossil findings such as mammal bones, gastropods, and palynomorph assemblages from the base of the Turgut Formation. According to these fossils, the formation started to deposit in a brackish-freshwater lacustrine environment during the late early Miocene-early middle Miocene interval (MN4-5) under warm, subtropical climatic conditions. The brackish conditions may be explained by a marine transgression in the region. The palynological and paleontological analyses from the lignite and underlying and overlying stratigraphy in the Turgut Formation mark a freshwater environment and warm-temperate climatic conditions during the middle-late middle Miocene (MN6-7). Th-230/U dating results of the uppermost levels of the lacustrine carbonates of the Milet Formation reveal a minimum radiometric age of 346 +/- 19 ka BP (middle Pleistocene). The uppermost levels of the Milet Formation overlapped the Goktepe Fault. 'this may imply continuous subsidence in the basin until similar to 346 ka.