Base on geological history evaluation using regional stratigraphy, sedimentary environments, magmatic activities, metamorphism and structural trend in Iran, physiographic-tectonic zoning map of Iran’s sedimentary basins has prepared. This map has prepared to point out the basement tectonics role in Iran. It contains twenty-four different provinces. Iran has composed from different plates: Arabian plate in south and west, Cimmerian manipulated in north and east, Eurasian plate in northeast margin. Cimmerian manipulated at least can be divided to the smaller part, East-Central Iran and North-Central Iran microcontinents. There are evidences for thick-skinned tectonics in the border zones of these plates and microcontinents, especially in Sanandaj-Sirjan overthrust belts that it formed by crustal stacking wedges. Also, Neoproterozoic-Phanerozoic Tectonic column in the Arabian, Cimmerian and Eurasian plates under Iran Country area have introduced.
The organization and development of the physiographictectonic provinces of Iran involves specifying the current structural geomorphology and tectonic history of Iran’s sedimentary basins that might have clear effect in the regions. A physiographic-tectonic province is a geological unit that it has a same history since sedimentation time to recent. Each physiographic-tectonic province has a same structural trend and dominant mechanism of deformation, because these have related to tectonic settings, magmatic histories, stratigraphic variations and deformational models of crust. So, physiographic-tectonic provinces can bind others. In this study, regional tectonics [
1) Geological data such as regional stratigraphy, sedimentary environments, magmatic activities, metamorphism, tectonic stages and deformational styles that provided much information on the tectonic history have gathered from different references; 2) Physiographic-tectonic zoning map of Iran’s sedimentary basins based on sedimentary basins position has identified. These basins described by some researchers [2-4]; 3) Structural units have limited for each individual physiographic-tectonic province based on different works such as [5-8]; 4) Tectonic units have limited for each individual identified plate and microcontinents (
At the first time, a geologist [
The structural provinces of Iran have studied by several researchers but in this study, a new Physiographictectonic zoning map of sedimentary basins (
Dominant structural trends in Zagros province (
part. From tectonics view, it contains the overthrust and simple fold belts of Zagros that formed on the northeastern part of Arabian plate’s passive margin (
Zagros Mountains have continued to East Taurus Mountains in Turkey and have named Zagros-East Taurus hinterland. Zagros-East Taurus hinterland is external platform (fold and thrust belt) of north margin of Arabian Craton (
Dominant structural trend in Persian Gulf foreland basin province (
Dominant structural trend in Makran province (
part uplifted and formed Makran range.
Dominant structural trend in Bashagard province (
Dominant structural trend in Jazmorian province (
Dominant structural trend in Shahsavaran-Soltan province (
Dominant structural trend in South Lut province (
Dominant structural trend in East Iran province (
Therefore, East Iran province has named Sistan or East Iran suture zone too. Recently, a dextral transpression zone (Nehbandan fault system) has developed on the eastern border of this province that it marked by horsetail splays on the northern and southern terminations (
Dominant structural trend in West-Central Alborz and lesser Caucasus province (
Recently, Damavand and Sebalan cones have formed by late volcanism that related to final subduction of oceanic slab in south Caspian basin toward south and southwest. Five dominant orogenic phases and four deformational events in Alborz Mountain building processes have suggested by [
The first deformational event is one from the Syn-collision type between Cimmerian and Eurasian plates (late Triassic) and the other ones are from post-collision deformational events and in with the deformational of sedimentary cover which is result of shortening and increasing the thickness of passive continental crust in north of Cimmerian miniplate.
Dominant structural trend in Great Kavir-Northern Urmieh lake province (
Also, this foreland basin in Pishva (Varamin) is a piggyback basin that formed on thrust sheets. In Tehran area, this basin is a deformed basin [
Dominant structural trend in South Great Kavir fold and thrust belt province (
Dominant structural trend in South Caspian-Black sea foreland basin province (
Dominant structural trend in Urmieh-Dokhtar province (
Dominant structural trend in Naien-Kerman province (
Dominant structural trend in Sanandaj-Sirjan province (
Quaternary basins such as southern margin of Urmieh Lake, Kabodarahang depression, Mighan Kavir, Gavkhoni depression, Abarkuh Kavir, Marvast Kavir and Sirjan’s Kavir-e Namak, on the north boundary of this province with Urmieh-Dokhtar are the index cases from Supra-Arc troughs. These basins are significant in marking loss of the fore-arc basin beneath back-thrusts antithetic to the subduction direction and can explain the presence of younger molasse in a setting referred to as a suture zone [
Dominant structural trend in East Alborz province (Fig-
ure 2) is NW-SE in eastern part and NE-SW in western part. From tectonics view, it contains Binalod magmatic arc and its fore arc basin with volcanic activities (especially in Silurian) on northeastern of Cimmerian miniplate. Obduction of Mashhad ophiolite during late Paleozoic has result of subduction into beneath this province (
Dominant structural trend in Torbat-e Jam-Neyshabour province (
A magmatic arc has formed on north and parallels to this province that it has underthrusted beneath East Alborz province since Paleogene. Torbat-e Jam-Neyshabour retro arc foreland basin has filled by erosion of that magmatic arc.
Dominant structural trend in Kopet Dagh province (
Kopet Dagh hinterland has uplifted related to Karakorum foreland basin in northeast along Eshghabad fault.
Dominant structural trend in South Caspian province (
Therefore it is a hybrid basin over an old island arc that it has formed by southward Paleotethyan intraoceanic subduction. This province is subducting beneath to Apsheron-Sill ridge [
Dominant structural trend in Great Kavir-Taibad province (
Dominant structural trend in Khaf-Bardeskan province (
Lut Plain-Gonabad back arc basin on the Lut microcontinent (eastern portion of East-Central microcontinent) has placed on the west of East Iran Mountain belt.
Dominant structural trend in East-Central Iran province (
Dominant structural trend in East-Central Iran province (
Dominant structural trend in East-Central Iran province (
Iran has composed from different plates: Arabian plate in south and west, Cimmerian manipulated in north and east, Eurasian plate in northeast margin.
Neoproterozoic-Phanerozoic Tectonic column in Zagros province under Iran country area (
1) Compressive event of late proterozoic (Pan African orogeny); 2) Tensional event of Infra-Cambrian; 3) Tensional event of Triassic; 4) Compressive event of Neogene (Zagrosian orogeny). Two above tensional events are related to regional rifting that it occurred next to the Gondwana drift. In global scale, they are approximately equivalent to movements of Caledonian and Hercynian orogenies, but in this period the Zagros basin have been formed a broad passive margin on the northeastern part of Afro-Arabian plate (
Neoproterozoic-Phanerozoic Tectonic column in Persian Gulf foreland basin province (
1) Compressive event of late proterozoic (Pan African orogeny); 2) Tensional event of Infra-Cambrian; 3) Tensional event of Triassic.
Compressive event of Neogene (Zagrosian orogeny) has not recorded in this province until recent. Similar to
the Zagros province, two above tensional events are related to regional rifting that it marked by some sedimentary gaps such as Carboniferous sequences.
Neoproterozoic-Phanerozoic Tectonic column in Cimmerian miniplate under Iran country area (
1) Compressive event of late proterozoic (Pan African orogeny); 2) Tensional event of Infra-Cambrian-Late Paleozoic (equivalent to movements of Caledonian and Hercynian orogenies) that it has marked by some sedimentary gaps such as in lower Paleozoic and Carboniferous sequences on the Alborz basin; 3) Compressive event of late Triassic (Early Cimmerian orogeny); 4) Tensional event of Late Jurassic; 5) Compressive event of Late early Alpine orogeny; 6) Tensional event of the Middle Alpine orogeny; 7) Compressive event of the Late Alpine orogeny.
Two later tensional events are related to back arc spreading (
Neoproterozoic-Phanerozoic Tectonic column in Eurasian plate under Iran country area (
1) Compressive event of late proterozoic (Cadomian orogeny); 2) Compressive event of Late Paleozoic (Hercynian orogeny); 3) Compressive event of late Triassic (Early Cimmerian orogeny); 4) Compressive event of the Late Alpine orogeny.
Geological history evaluation using regional stratigraphy, sedimentary environments, magmatic activities, metamorphism and structural trend in Iran are showing that it contains twenty four different provinces.
There are much evidence for three main continentcontinent collision such as magmatic arcs, ophiolitic sequences, orogenic belts and them foreland basins. The first one is along northern boundary of Binalod (16) and West-Central Alborz and lesser Caucasus (9) provinces that it known as Paleotethyan suture zone.
The second continent-continent collision zone is along northern boundary of Sanandaj-Sirjan province (15) that it known as Neotethyan suture zone and it has formed on the top of the crustal stacking wedges. The third continent-continent collision zone is along eastern boundary of Lut Plain-Gonabad province (22) that it known as mezotethyan suture zone. Base on gravimetric survey of Iran [
Also, there are some evidence for an ocean-continent covergence such as Makran accretionary prism (province No. 3), Jazmorian-Mashkel fore arc basin, (province No. 5), Shahsavaran-Soltan magmatic arc (province No. 6), South Lut-South Helmand back arc basin (province No. 7).
The Paleotethyan and Neotethyan suture zones have same orientations (NW-SE) from median part of Iran toward west and so, four different mountain ranges have formed.
They are the most parts of Zagros-East Taurus hinterland with deformed sedimentary rocks (province No. 1), West-Central Alborz and lesser Caucasus hinterland with deformed volcano-sedimentary rocks (province No. 9), Urmieh-Dokhtar Magmatic Arc (province No. 13) and Sanandaj-Sirjan overthrust belt with deformed metamorphic rocks (province No. 15).
These have formed a broad mountain chain with more than 1200 km length and 400 km width from the southern part of Caspian sea to Black sea. Four above mountains have different ages, basements, structural styles and rocks, thus it seem that they can consider as Iranian Cordillera.
Physiographic-tectonic zoning map of Iran’s sedimentary basins has prepared to indicate basement tectonics role in Iran. Characteristic of this zoning map are as follows:
The map has intended as a pattern for the assessment of the structural trends in Iran.
• Cimmerian miniplate at least can be divided to the smaller part, East-Central Iran and North-Central Iran microcontinents.
• Zagros and Alborz hinterlands and border zones of East-Central Iran microcontinent have thick-skinned tectonics.
• Sanandaj-Sirjan province has formed on the crustal stacking wedges of Arabian plate.
• East Alborz orogeny is the oldest mountain building Iran.
• Tectonic events of Paleozoic (equivalent to movements of Caledonian and Hercynian orogenies) in the most part of Iran have a tensional role and they have marked by long sedimentary gaps.
• Paleozoic sedimentary gaps are related to block faulting in rifted region.
• Iran country has composed from four mountain ranges that they can consider as Iranian Cordillera.
This work has funded by the Department of geology, Islamic Azad University, Science and Research branch, Tehran, Iran. Also, Special thanks to vice-president for research in Science and Research branch, Tehran.