GSINET | Geological Survey of Iran , North - East Territory

Writers : M. Mohajjel,M. Sahandi
Refference : Geosciences Scientific Quarterly Journal,No.:31-32,P.:28
Publishing Year : 1378

Abstract :

The SanandaJ -Slrjan Zone Is the metamorphic cor. of the Zagros Orogen In south-western Iran. It is formed In the Late Cretacsous, during closure of the Neo-Tethys, and when Afro-Arabian Continent collided with central iran. Subdivision is Proposed for the Sanandaj-Sirjan Zone is based on the recognition of Late MesozoIc Continental margin arc, being formed during northeastward subduction of Neo-Tethys� under Iranian continent. From southwest to northeast the subdivision consists of the following subzones.(1)The radiolarite sub-zone consisting of Late Triassic to Late Cretaceous shallow to deep-marine rocks.(2)The Bistoon sub-zone, constituting Late Triassic to Late Cretaceous shallow marine carbonates.(3)The Ophiolite sub-zone comprising several Late Cretaceous ophiolites,(4)The marginal sub.zone has a Late Jurassic-Early Cretaceous volcanic arc succession deposited in shallow-marine environments,(5)The Complexly-deformec sub-zone has a Late Palaeozoic-Mesozoic Passive margin succession formed at the northeastern side of Neo-Tethys, as well as beinç overlain by a convergent margin assemblage. Two regoinal deformations are recognised in the Complexly-deformed sub-zone with the firs one related to subduction of Neo-Tethyan oceanic crust and associated with arc volcanism during the Late Jurassic-Early Cretaceoos. Th! second regional deformation occurred in Late Cretaceous collision and consists of southwest-vergent intense folding in the metamorphk inner sub-zone and imbricate thrusting in the outer sub-zone. Collisional tectonics in a regime of dextral transpression was renewed in the Neogene.

Subject List : Structural evolution

Quarterly

Tectonic evolution of Sanandaj-Sirjan Zone