A Preface to the Paleostress Reorientations in the Kopet-Dagh after Triassic Period

The Kopet Dagh (KD) mountain belt in the northeast of Iran contains a sequence of Jurassic-Pliocene folded sedimentary rocks which unconformably covers deformed sedimentary and pyroclastic units of Triassic age and older one. In order to understand a part of tectonic history and the orientation of deforming stress fields, brittle structures were collected and analyzed by Right Dihedra methods. The results show that the KD basin was formed in a NW-SE extensional regime during the Early and Middle Jurassic. Although there is some evidence of compression along the same axis during the Late Kimmerian phase (Late Jurassic – Early Cretaceous), it seems that the Cretaceous layers were folded by a NE-SW compression during the Paleocene. Afterward, the compression stress field has re-oriented to N-S direction and generated the present day strike-slip system following the Miocene.