The Morphotectonic Analysis of the Formation of Playa Depressions of the South and Southeast of Shirkouh Mountain in Plio-Quaternary

Various morphotectonic landforms have been created by the activity of the Dehshir Fault and the 2nd and 3rd degree Riddle faults in Plio-Pleistocene. The most important of these can be the structural depressions of Abarghoo and Taghestan along the faults derived from the Dehshir Fault in the west and smaller and numerous other depression such as Rashkouieh, Ernan, Chah Shir and Chah Torsh along the eastern faults of the Dehshir Fault. The purpose of this study was to investigate the western depressions of the Dehshir Fault in the south and southeast of Shirkouh Mountain in the south of Yazd city. The results showed that these depressions, like many other closed depressions in central Iran including Gavkhuni, have been formed due to the transtension of a stretched-separated basin. The study area was located in a cutting zone between the two active dextral faults of Dehshir-Baft and Rafsanjan-Ernan. The counterclockwise rotation of the fault block between the mentioned two faults has created local extensional zones and reduced the crustal thickness. This has uplifted the geothermal curves and partial melting and created local post-Pliocene local volcanism. Following this phenomenon, several dacitic domes have formed along the fault strike and intersection in the south and southeast of the Shirkouh Mountains and the folding of Miocene sediments. The activity of the faults, along with the rise of the domes, has led to the fragmentation of the previous smooth surface, and has caused the subsidence of some parts of the area and created several structural depressions