Stratigraphic comparisons along the Pontides (Turkey) based on new nannoplankton age determinations in the Eastern Pontides: geodynamic implications

We compared the stratigraphic formations along the southern margin of the Black Sea using 196 nannoplankton ages determined in the Western and Central Pontides and 112 new samples from the Eastern Pontides. We inferred that the I. stanbul and Sakarya zones were amalgamated prior to the Early Cretaceous. Extensional subsidence migrated eastwards along the Pontides from the Barremian to the Paleocene. The eastwards younging of the Cretaceous magmatism suggested that the eastern Black Sea Basin is younger. Locally, angular unconformities and a stratigraphic gap testify to the Late Albian uplift of the Central Pontides as a consequence of the collision of an oceanic edifice. Cretaceous Oceanic Red Beds are marker beds of Santonian age along the much of the Pontides and are of mainly Campanian age within the Eastern Pontides. The Middle Campanian-Paleocene was a non-volcanic period characterized by extensional subsidence mainly along the eastern Black Sea Basin. The end of Cretaceous volcanism can be correlated with a southwards subduction jump. Syn-compressional basins show that contraction started during the Ypresian along the entire Pontide belt. Eocene volcanism started earlier in the north (Lutetian) than in the south (Bartonian) of the Eastern Pontides. This propagation of syn-collisional volcanism could have resulted from slab steepening under the Eastern Pontides