New stratigraphic data concerning the marine Oligo-Miocene formations of the Sivas Basin (Turkey) [Nouvelles données stratigraphiques concernant les formations oligo-miocènes marines du bassin de Sivas (Turquie)]
The stratigraphy of the marine Oligo-Miocene formations of the Sivas basin has been revised on the basis ofplanktic and benthic fauna and microfauna. In the Sivas area, three of the main structural units present three distinct sequences which correspond to three paleoenvironments: basinal open marine, coral platform and, lagoon at the margin of emergent areas. The Oligocene age of the massive gypsum is confirmed. Due to the presence of continental sequences of the same age to the west and to the south of Sivas, the direct connexion with the Eastern Mediterranean appears more difficult to interpret.