Mustafa Yücel Kaya, MSc.

Cretaceous – Paleogene Proto-Paratethys Sea incursions in Central Asia and effects of these incursions on the Asian Paleoenvironment

During the Cretaceous and Paleogene, marine environments of a shallow epicontinental sea named differently as the Tarim Sea, Tajik Sea, Turan Sea or Proto-Paratethys Sea extended across Eurasia from the Mediterranean Tethys to the Tarim Basin in western China. This sea separated and became isolated as the Paratethys Sea during the latest Eocene or early Oligocene as a result of stepwise westward retreat. The present day remnants of the Paratethys Sea are the Black Sea and the Caspian Sea. A total of five marine incursions of the Proto-Paratethys sea into the western Tarim Basin during Late Cretaceous to Paleogene were identified from the sedimentological records. The 1st marine incursion in the Tarim Basin was generally reported as a Cenomanian transgression due to a sea invasion from the neighboring basins in the west through the present-day Alai Valley. An earlier first marine incursion in Early Cretaceous in the Tarim Basin was also proposed based on some scarce paleontological (trace fossils), mineralogical and geochemical evidences. The eastward extent of these incursions into the Tarim Basin varied through time with a maximum extent during the 3rd incursion supposedly during early Eocene. By using biostratigraphy and magnetostratigraphy Roderic Bosboom (previous PhD of Guillaume Dupont-Nivet) accurately dated the 4th and 5th marine incursions in the southwestern Tarim Basin. Roderic Bosboom also revealed the similarity of the records of the marine incursions documented in the Afghan-Tajik, Fergana and Alai Valley basins to the records in the Tarim basin. The records of both the 4th marine incursion of Lutetian age and the 5th incursion of latest Bartonian–early Priabonian age recognized in the Tarim Basin can be identified across Central Asia in Afghan-Tajik, Fergana and Alai Valley epicontinetal basins. Following Roderic’s footsteps a multidisciplinary way of research involving sedimentology, biostratigraphy, magnetostratigraphy, thermochronology and stable isotope geochemistry will be applied to construct a regional stratigraphic framework for the 3rd, 2nd and 1st sea incursions both in the SW Tarim and Tajik Basins. This regional stratigraphic framework and the high resolution age control will enable us to understand more about the relation between the sea incursions and the paleoenvironmental changes in central Asia. By using isotope geochemistry, biostratigraphy and magnetostratigraphy (if possible) records of some significant climatic events like PETM will be searched at the corresponding levels of the studied sections both in the Tarim and Tajik basins.

- Kaya, M.Y. & Altiner, D., 2015, Microencrusters from the Upper Jurassic - Lower Cretaceous Inalti Formation (Central Pontides, Turkey): remarks on the development of reefal/peri-reefal facies, Facies, 61:18.
- Kaya, M.Y. & Altiner, D., 2014, Terebella lapilloides Münster, 1833 from the Upper Jurassic - Lower Cretaceous Inalti Carbonates, Northern Turkey: Its taxonomic position and Paleoenvironmental - Paleoecological Significance, Turkish J Earth Sci, 23: 166-183.