Environmental and ecological changes across the Permian–Triassic transition in Türkiye: integrating virtual outcrop models and new fieldwork data

The Permian–Triassic transition is characterized by major environmental changes (e.g., hyperthermals, perturbations in carbon cycle) and the largest known mass extinction event in the Phanerozoic. However, successions with a relatively complete sedimentological and paleontological record across the Permian–Triassic are limited to a few well-known sections in Europe and South China. Here, we synthesize sedimentological, geochemical and paleontological data from the Permian–Triassic succession of southwestern Türkiye, putting it into a consistent stratigraphic framework and incorporate 3D open-access virtual outcrop models with a virtual field guide to improve the accessibility, reproducibility and sustainability of fieldwork findings. The fossiliferous Upper Permian to Lower Triassic successions in the studied locations reach over a kilometer thickness. In addition, due to the contemporaneous opening of the Neotethys Ocean the sedimentary units from the Antalya Nappe (Çürük Dağ, Kemer; Öznurtepe, Gazipaşa, Demirtaş) were deposited on a carbonate platform in the Neotethys ocean, while successions from the Aladağ Nappe (Taşkent) were deposited on the northern side of the carbonate platform towards the subducting Palaeotethys Ocean. In all sections, the Changhsingian (uppermost Permian) is represented by highly fossiliferous platform carbonates. The Changhsingian successions terminate with a thin oolitic grainstones (“transitional oolites”), which is quantitatively identified as the Permian–Triassic mass extinction interval and corresponds with a negative carbon isotope excursion. The limited availability of geochemical proxies, however, hinders our understanding of the drivers of the extinctions. The transitional oolites are overlain by a microbialite-dominated carbonates deposited in the Griesbachian, and then oolites. This carbonate-rich deposition was replaced with a mixed carbonate-siliciclastic dominated succession later in the Early Triassic (Dienerian–Spathian), where marine ecosystems slowly recover. These environmental and biotic changes are similar to the known record from the tropical paleolatitudes in the western (Italy, Hungary) and eastern Palaeotethys (Iran, China).