Writers : Shahidi,Ali Reza; supervisor: A. Aghanabati; advisor: A. Saeidi
Refference : M.Sc.Thesis- GeoSciences Research, Geological survay of Iran; page192
Publishing Year : 1381

Abstract :

Structural belt of East Iran includes an approximately NS continental orogenic complex. Thc oldest rocks of this block are of Pre Cambrian age due to stratigraphic and petrology example it inferences that there was a rifling between Iranian and Afghan continents. That caused easi Iran ophiolite obducting during Cretaceous era. In the same time sedimentation has occurred There has been a continental environment after rifling closure in Late Cretaceous. A lineai magmatic activity has been seed. During this tectonic evolution from that time to now. Flowei structures and riedel system derived from a pull apart basin occur during evolution anc deployment of fault systems and they make production and propagations of differeni .sedimentary basins.
Stratigraphical and structural evidence indicate that the created marine at Upper Middlc Jurassic led to an oceanic crust at that time. That was closed at the Late Cretaceou Companian-Maestrichtian) so that, Lut and Helmand blocks collided due to that. It seems, ir( that process, some parts of oceanic crust eliminated during a subduction which math metamorphism and magmatism in the Western Afghanistan. Now, the remnant of that crust i5 seen along the collision zone as ophiolitic complex. It appears, those units separated from Easi Iranian ophiolites and emplaced along the Northern wedge of Lut block due to north-souti ,faults (Nehbandan) and anticlockwise movement of Lut and Tabas blocks.
In the northern regions of studied area, there are wide outcrops of volcanic rocks indicating strong volcanism, which started from Eocene and continued to Late Tertiary to Plio Quaternary. They are rhyolite, rhyodacite, dacite, andesite, andesibasalt and basalt in composition and accompanied by pyroclastics, volcanic berccia and ignimbriteIn this research, paleontological and petrographical studies in addition to macroscopic characteristics of rock units of two selected sections of Upper Cretaceous in Shoshood ares show that during the Late Cretaceous the basin was impressed wholly by the prevailed tectonic .regime particularly the strike slip and normal faults.
That made variable depth conditions and water energy in the basin. That is well interpreted by lateral changes of sedimentary facies and show that the progress of basin has not been as muclas to create an oceanic crust in relative to other East Iranian basins. Besides, the sedimentology processes was going on up to Late Cretaceous without interruption due to any compressional force.

Subject List : Tectonostratigraphy