Abstract

Kermanshah is part of the structural zone of autochtone Zagros in the boundary of Arabian and Iran plates. Stratigraphy sequence of upper cretaceous in two structural blocks of Kouh-e-Sefid in south and Kouh-e-Nesar in southwestern of Kermanshah up to Campanian stage was observed as similar sequence. There is a function of existing faults in area with distinct sedimentary condition in every block with each other, so that there is a reef sedimentary facies residue from collection of thick bed to massive limestone. While transitionally, in the block of Kouh-e-Sefid and Campanian, Marly limestone of Ilam formation changes to shalls of Gourpi formation in Kouh-e-Nesar. In Maestrischtian the block of Kermanshah's Kouh-e-Sefid suddenly forms Kermanshah reef which reaches detrical facies of sity shalls and siltstone and sandstones, which is equal with Amiran formation. Finally, Radiolarites sequence, located as a thrust on the Amiran formation, is observed as sedimentary sequence mentioned earlier; while in Kouh-e-Nesar's block, Gourpi formation is changed to Amiran formation by transitional boundary which in continuance this formation is finished by a disconfirmity to Kashkan's detrical formation that belongs to Eocene. Based on existing evidences, branchy function of Zagros thrust in the south of Kermanshah from Campanian causes sedimentary condition in two blocks which differ from each other.

Key words: Dynamic stratigraphy, Zagros, structural block, microfacies.