BERDIGA TERRANE AND ITS ROLE IN THE DEVELOPMENT OF EAST PONTIDE (TURKEY)

Stratigraphic investigations in East-Pontides reveal that Berdiga Formation, developed in neritic facies, has a stratigraphic range from Callovian to Late Aptian. The regional allocation of this kind of a stratigraphic development has the geographic distribution between: in south ca. Maden (Bayburt) – Reþadiye line; in north Degirmendere-Bridge 23 (ca. 15 km south-west of Maçka-Trabzon); in east Uluçayýr-Yerlice line (ca. 10 km east of Bayburt); and in west ca. Fatsa-Niksar line. This area must have been an oceanic plateau during Callovian – Aptian- Albian time interval, whereas its confining neighbourhoods were deeper marine environments during the same time interval. With the onset of Late Cretaceous collisions between terranes get its start and very strange stratigraphic sequences like Bayburt-cataclastic melange, ophiolitic melanges at different locations, etc. were developed at terrane contacts. The convergent movements between terranes continued during Late Cretaceous and either subduction zones or strike-slip tectonics developed alongside of borders. At the end of Cretaceous most parts of Berdiga Terrane were uplifted and subdued to erosions during Paleocene. With the onset of Eocene some parts of this region were submerged again and Eocene deposits with very different sedimentologic characters developed. Convergent movements between terranes continued further after Eocene and deep-marine sediments and ultramaphic rocks of oceanic crust (indicating a deep environment) were up-thrusted over the confining oceanic plateaus.