الملخص

The contact between Bekhme and Shiranish Formations is studied paleontologically in Bekhme gorge and Rawanduz area. The nannofossils are used to prove that the age of the base of the Shiranish Formation is lower late Campanian and middle Campanian in Bekhme gorge and Rawanduz area respectively. The older age of the Rawanduz area is attributed to early drowning (flexing downward) of the forebulge of the Arabian platform due to southwest propagation of tectonic load of the Zagros Orogen during early stage of collision of Afro-Arabian and Iranian plates by which the Tethys ocean closed later.