Statigraphy and tectonics of the Pulur (Bayburt) region in the eastern Pontides

Okay A., Sahinturk O., Yakar H.

Bulletin - Mineral Research and Exploration Institute of Turkey, vol.119, pp.1-24, 1997 (Scopus) identifier


The Pulur (Bayburt) region in the Eastern Pontides is a typical Alpide fold and thrust belt. In the region a relative autochthon and three north-vergent thrust sheets are differentiated, which are the Cebre relative autochthon, and the Hamurkesen, Asutka and Imalidag thrusts sheets. When the thrust stack is palinspastically restored, the Jurassic-Lower Cretaceous sequences in the thrust sheets represent depositional settings that range from shelf in the north to oceanic crust in the south. The Cebre relative autochthon consists of Upper Carboniferous sedimentary rocks, neritic Jurassic limestones and Upper Cretaceous hemipelagic clastic and carbonate rocks. The Cebre relative autochthon is tectonically overlain by the Hamurkesen thrust sheet, which consists of Jurassic volcanoclastic rocks, uppermost Jurassic oolitic limestones, and a thick sequence of Lower Cretaceous pelagic micrites. The next overlying thrust sheet, the Asutka sheet, comprises a crystalline basement of cordierite-sillimanite-schist, gneiss and amphibolite, which is unconformably overlain by Jurassic volcanoclastic rocks and Lower Cretaceous pelagic micrites. The Lower Cretaceous limestones are tectonically overlain by an ophiolitic melange, which is unconformably overlain by the Maastrichtian neritic limestones and a Paleocene-Lower Eocene flysch. The Imalidag thrust sheet of Jurassic-Cretaceous pelagic micrites, lies tectonically over the Paleocene-Lower Eocene flysch. It forms a pop-up structure and rests in the south over the ultramafic rocks of the Ankara-Erzincan Neo-Tethyan suture. During the Cenomanian-Turonian the ophiolitic melange was obducted northward over the south-facing passive continental margin of the Eastern Pontides, This obduction event was probably caused by the attempted subduction of the Eastern Pontide continental margin in a south-dipping intra-oceanic subduction zone. The polarity of the subduction changed after this event and the Tethyan ocean floor started to subduct northward under the Eastern Pontides. This led to the development of a major Senonian volcanic arc in the outer Eastern Pontides, while the inner Eastern Pontides including the area studied were in fore-arc position. The thrust and fold tectonics developed during the collision between the Eastern Pontides and the Anatolide-Tauride microplate, which took place in the Late Paleocene-Early Eocene. Post-collisional Middle; Eocene marine limestones and sandstones overlie unconformably the various thrust sheets.