STRATIGRAPHY AND TECTONICS OF THE PULUR (BAYBURT) REGION IN THE EASTERN PONTIDES

Yıl 1997, Cilt: 119 Sayı: 119, 1 - 24, 01.12.1997

Aral I. Okay Ömer Şahintürk Hüseyin Yakar

Öz

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, Aşutka and
İmalıdağ 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 Aşutka 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

Anahtar Kelimeler

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