European Union of Geosciences, Strasbourg, France, 28 March - 01 April 1997, vol.4, no.1, pp.72
Northcentral Anatolia comprises three main tectonic units: the Istanbul Zone in the north and the Sakarya Continent in the south. The Armutlu-Ovacik Zone lies between these two east - west trending continental fragments. The zone constitutes fault-bounded slivers of different origin, dragged both from the Istanbul Zone and the Sakarya continent.
The three tectonic units are presently bounded by the two branches of the North Anatolian Transform Fault. However these two fault systems appear to have already formed during the development of the Armutlu - Ovacik Zone. In order to distinguish the older structure from the North Anatolian Fault, we called the farmer here as The Western Pontide Fault. In this talk the Armutlu - Ovacik Zone and the Western Pontide Fault will be described, and its tectonic significance within the context of the geological evolution of the region will be discussed.
The field data indicate that a basin was developed along and including the place of the Intra - Pontide suture separating the Istanbul Zone from the Sakarya Continent during the early Late Cretaceous. During the terminal closure of the Intra-Pontide ocean transtensional tectonic effected the part of the region, where a new basin began to develop above the amalgamated tectonic mosaic consisting of the Istanbul - Zonguldak tectonic unit and the Sakarya continental units. Consequently a thick syn-tectonic sedimentation began to form during the late Campanian - early Maastrichtian period. The basin units covered the entire Western Pontides, during the early Paleocene. The sea invaded the previously elevated terranes and thus formed a common cover for the first time. In the early to middle Eocene the basin was closed under the newly generated transpressional tectonic regime.