Mehraj Aghazadeh | Payam Nour University (original) (raw)

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Papers by Mehraj Aghazadeh

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-oceanic ridge

Research paper thumbnail of Ages, Geochemistry and Sr-Nd-Pb Isotopes of Alkaline Potassic Volcanic Rocks from the Arasbaran Region (Nw Iran): Evidence for Progressive Evolution of Mantle Sources During the Neotethyan Subduction System

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-ocean ridge

Journal of the Geological Society

Numerical simulations and theoretical analyses predict that forearc ophiolites probably record th... more Numerical simulations and theoretical analyses predict that forearc ophiolites probably record the end of subduction followed by re-initiation. We report here the results of a field study and new geochronological data that enable identification of the Kermanshah forearc basin, SW Iran. This basin is filled with two terrestrial volcaniclastic successions separated by an Upper Cretaceous reef facies limestone. Early Late Cretaceous ocean island basalts, early Eocene incompatible element-enriched mid-ocean ridge basalts/normal-type mid-ocean ridge basalts and late Eocene arc basalts of the basin indicate that Neotethyan subduction ended during the early Late Cretaceous and then re-initiated during the late Eocene. We suggest that the Neotethyan Ocean between the Iranian and Arabian continents consisted of leading and trailing oceanic plates separated by a mid-ocean ridge (MOR). Subduction of the leading plate generated the Jurassic–Early Cretaceous Sanandaj–Sirjan arc, which was ended ...

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-ocean ridge

Journal of the Geological Society

Numerical simulations and theoretical analyses predict that forearc ophiolites probably record th... more Numerical simulations and theoretical analyses predict that forearc ophiolites probably record the end of subduction followed by re-initiation. We report here the results of a field study and new geochronological data that enable identification of the Kermanshah forearc basin, SW Iran. This basin is filled with two terrestrial volcaniclastic successions separated by an Upper Cretaceous reef facies limestone. Early Late Cretaceous ocean island basalts, early Eocene incompatible element-enriched mid-ocean ridge basalts/normal-type mid-ocean ridge basalts and late Eocene arc basalts of the basin indicate that Neotethyan subduction ended during the early Late Cretaceous and then re-initiated during the late Eocene. We suggest that the Neotethyan Ocean between the Iranian and Arabian continents consisted of leading and trailing oceanic plates separated by a mid-ocean ridge (MOR). Subduction of the leading plate generated the Jurassic–Early Cretaceous Sanandaj–Sirjan arc, which was ended ...

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-ocean ridge

Journal of the Geological Society, Sep 8, 2022

Numerical simulations and theoretical analyses predict that forearc ophiolites probably record th... more Numerical simulations and theoretical analyses predict that forearc ophiolites probably record the end of subduction followed by re-initiation. We report here the results of a field study and new geochronological data that enable identification of the Kermanshah forearc basin, SW Iran. This basin is filled with two terrestrial volcaniclastic successions separated by an Upper Cretaceous reef facies limestone. Early Late Cretaceous ocean island basalts, early Eocene incompatible element-enriched mid-ocean ridge basalts/normal-type mid-ocean ridge basalts and late Eocene arc basalts of the basin indicate that Neotethyan subduction ended during the early Late Cretaceous and then re-initiated during the late Eocene. We suggest that the Neotethyan Ocean between the Iranian and Arabian continents consisted of leading and trailing oceanic plates separated by a mid-ocean ridge (MOR). Subduction of the leading plate generated the Jurassic–Early Cretaceous Sanandaj–Sirjan arc, which was ended by MOR–trench collision. The Zagros late Early Cretaceous forearc ophiolites represent the youngest/hottest segments of the leading plate emplaced during the MOR–trench collision. Subsequently, subduction of the MOR generated the forearc basin and basalts with diverse geochemistry. After c. 60 myr, the cooled trailing plate started to subduct, generating the late Eocene arc basalts. This model has significant implications for investigating and understanding other fossil subduction zones elsewhere in the world. Supplementary material: Supplementary material is available at https://doi.org/10.6084/m9.figshare.c.6086586

Research paper thumbnail of Rogenesis and U-PB Age Dating of Intrusive Bodies in the Sar Cheshmeh Deposit

فصلنامه علمی-پژوهشی علوم زمین, Dec 1, 2016

Research paper thumbnail of Post-Collisional Shoshonitic, C-type Adakitic and Lamprophyric Plutonism in the Khankandi Pluton, Arasbaran (NW Iran)

فصلنامه علمی علوم زمین, Feb 20, 2011

Research paper thumbnail of Geochemistry, Origin and Geodynamic Environment Intrusion Zaker-Sorkheh Dizaj in the Southern Limb of the Tarom Subzone, East of Zanjan

Research paper thumbnail of Petrogenesis of NW of Bam Volcanic Rocks

Research paper thumbnail of Petrology and Petro Genesis of Alkaline and Calc-Alkaline Lamprophyres in the NW Iran

فصلنامه علمی-پژوهشی علوم زمین, Mar 1, 2015

Research paper thumbnail of Ore mineralogy and geochemistry of the productive intrusive bodies in Guydash Fe-Skarn deposit, East Azarbaijan Province

Iranian Journal of Crystallography and Mineralogy

Research paper thumbnail of Geochemistry, Petrogenesis and dating of lamprophyric dykes in the Kaleybar area, NW Iran

Iranian Journal of Crystallography and Mineralogy

Research paper thumbnail of Latest Oligocene adakitic rocks in western Iran: implications for early crustal thickening and tectonic evolution of the Iran Block

Journal of the Geological Society

Adakitic rocks occur in a variety of tectonic settings and are key to understanding the tectonic ... more Adakitic rocks occur in a variety of tectonic settings and are key to understanding the tectonic evolution and geodynamics of orogenic belts. We investigated latest Oligocene (23.5–22.5 Ma) quartz monzonites and granites from the western segment of the Urumieh–Dokhtar magmatic belt in Iran, which are likely to have formed in response to the early stages of Arabia–Eurasia collision. The studied rocks have the geochemical characteristics of typical adakites, such as high SiO 2 (60.18–68.82 wt%) and Sr (499–793 ppm) contents, low Y (8.90–17.1 ppm) and Yb (0.88–1.58 ppm) contents, and high Sr/Y (26.1‒67.8) and (La/Yb) N (21.9‒32.9) ratios. They have variable K 2 O (3.88–5.09 wt%), MgO (0.44–2.74 wt%; Mg# = 33.7–52.5), Cr (4.27–40.59 ppm), Ni (4.28–35.68 ppm) and Th (9.56–59.59 ppm) contents, and relatively depleted Sr–Nd isotopic compositions [( 87 Sr/ 86 Sr) i = 0.70450–0.70516; ε Nd ( t ) = 2.1–2.7]. These characteristics indicate that the quartz monzonites were derived from the part...

Research paper thumbnail of Zircon Hf isotope of Iranian porphyry copper deposits: Constraints on the source of porphyry Cu magma

Petrology, 2016

In this research, zircon Hf isotopic ratios from Sungun, Sar Cheshmeh, Meiduk, Darreh Zar and Bon... more In this research, zircon Hf isotopic ratios from Sungun, Sar Cheshmeh, Meiduk, Darreh Zar and Bondar Hoza porphyry mineralized intrusions has been studied. The Hf isotopic ratios in the studied porphyry intrusions are similar and the average of zircon eHf values from Sar Cheshmeh, Meiduk, Darreh Zar, Bondar Hanza and Sungun porphyry intrusions are +8.2, +9.3, +9.2, +10 and +8.6, respectively. Also, the averages of zircon TDMC ages from the Sar Cheshmeh, Sungun, Meiduk, Darreh Zar and Bondar Hanza porphyry intrusions are 573, 550, 502, 510 and 464, respectively. The positive and restricted eHf values in the studied porphyry intrusion zircons along with the lack of inherited zircons shows continental crust did not contribute in the evolution of the porphyry magmas. The eHf in the studied zircons is between depleted mantle and lower crust values with a tendency towards the depleted mantle. According to adakitic nature of studied porphyry intrusions, post collisional tectonomagmatic set...

Research paper thumbnail of Petrological and isotopic study of basaltic rocks of Barzand area and comparison with Poshtasar originat basalts in South of Germi

Petrology, 2019

basaltic rocks in Barzand area (Continue to Kousmalyn basaltic rocks in Iran) show parallel trend... more basaltic rocks in Barzand area (Continue to Kousmalyn basaltic rocks in Iran) show parallel trend with Poshtasar basalt and they have older age according to stratigraphy in comparison with Poshtasar basalts. These basalts whit prismatic structure mostly have mugearitic composition and show hyalomicroporphyritic and glomeroporphyritic textures. The main minerals are Ca-rich plagioclase and diopsidic clinopyroxenes. Leucites generally have been altered to analcime. The parent magma of these rocks has a potassic and shoshonitic nature. In multi- element diagrams Ta, Ti and Nb show depletion and LILE, LREE have enrichment that suggests their primary magma have been originated from a subduction related mantle source. According to radiogenic isotopic ratios, mantle source of Barzand basaltic rocks have been drived from a fertilized mantle source during 0.8 to 0.9 billion years ago. According to initial 87Sr/86Sr (0.70499 ± 0.0004) and initial 143Nd/144Nd ratios (0.5127 ± 0.0004) estimated...

Research paper thumbnail of Geochemistry and petrogenesis of Eocene shoshonitic ‎and adakitic volcanic rocks in Sonajeel area ‎(Southeast of Heris, Eastern Azerbaijan)‎

Petrology, 2018

The studied area is located in the SE of Heris (Eastern Azerbaijan province) and the Alborz-Azerb... more The studied area is located in the SE of Heris (Eastern Azerbaijan province) and the Alborz-Azerbaijan structural zone. The Eocene volcanic rocks in the area of under study show various compositions ranging from olivine basalt, hornblende basalt, basaltic andesite and andesite to trachy andesite. The studied basaltic rocks, except for amphibole types, which show calc-alkaline affinity, mainly have shoshonitic and the andesitic rocks are adakitic composition. According to primitive mantle and chondrite normalized spider and REE diagrams, the studied rocks are characterized by LILE and LREE enrichment and pronounced depletion in HFS elements. Based on geochemical data the basaltic rocks have been originated from different degrees partial melting of a heterogeneous lithospheric mantle that metasomatized by subduction agents. The adakitic rocks have been generated from partial melting of thickened potassic mafic lower crust that have been metamorphosed in eclogitic facies.

Research paper thumbnail of Two plutonic complexes of the Sanandaj-Sirjan magmatic-metamorphic belt record Jurassic to Early Cretaceous subduction of an old Neotethys beneath the Iran microplate

Gondwana Research, 2018

Abstract The Neotethyan tectonics of the Zagros orogenic belt, SW Iran remains still hotly debate... more Abstract The Neotethyan tectonics of the Zagros orogenic belt, SW Iran remains still hotly debated in comparing with its western counterparts. One major issue concerns the timing and nature of the Sanandaj-Sirjan magmatic-metamorphic belt (SSMB), which is made predominantly of metamorphic rocks and Jurassic to Early Cretaceous large plutonic complexes. The Alvand and Qory are two largest plutonic complexes locating in north-central and southern segments, respectively, of the SSMB. Careful LA-ICP-MS U/Pb analyses of the magmatic zircons from the Alvand plutonic complex reveal a smooth spectra, along which the concordant age increase gradually from 120 to 190 Ma; while that of Qory is step-like consisting of two stages, a Jurassic and a late Early Cretaceous ones, respectively. New geochemical data, combined with zircon Lu/Hf results suggest that (1) the Alvand granitoids mostly resulted from a long-lived, successive injection of juvenile-crust-sourced magma batches without obvious fractionation crystallization (FC); but (2) the two stages granitoids of the Qory complex both generated by FC of juvenile-crust-sourced magmas; and (3) the gabbros of the Alvand complex are geochemically of E-MORB-affinity while those of the Qory complex are typical continental arc mafic rocks. Previously published petrological and 40Ar/39Ar data have identified a broken, Jurassic to Early Cretaceous high-pressure metamorphic belt to the southwest of the SSMB, which likely represents the closed, southeastern equivalent of the northern Neotethyan Ocean, north of the Taurides-Anatolia-Armenia block. Thus, the SSMB in Iran, the Kapan belt in Caucasus, and the Serbo-Macedonian belt in northern Turkey form a huge Jurassic to Early Cretaceous continental margin arc system recording northeastwards subduction of the older Northern Neotethyan Ocean beneath Eurasia. The Albian-Cenomanian ophiolites such as Koy, Kermanshah, and Neyriz in Iran represent the eastern counterpart of the younger Southern Neotethyan Ocean, south of the Taurides-Anatolia-Armenia block. During the subduction of the Old Neotethys, an intraplate transform fault likely opened and generated a slab-window beneath the Alvand region, which provided a constant energy source to steadily heat the low crust. This model satisfactorily interprets the unusual geochronological framework and geochemistry of the Alvand complex.

Research paper thumbnail of Geological, Alteration and Mineralization Characteristics of Ali Javad Porphyry Cu-Au Deposit, Arasbaran Zone, NW Iran

Open Journal of Geology, 2016

Research paper thumbnail of Post-collisional monzonitic magmatism from the Zagros hinterland. Implications on lithospheric processes

Research paper thumbnail of Geochemistry, Sr–Nd–Pb isotopes and geochronology of amphibole- and mica-bearing lamprophyres in northwestern Iran: Implications for mantle wedge heterogeneity in a palaeo-subduction zone

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-oceanic ridge

Research paper thumbnail of Ages, Geochemistry and Sr-Nd-Pb Isotopes of Alkaline Potassic Volcanic Rocks from the Arasbaran Region (Nw Iran): Evidence for Progressive Evolution of Mantle Sources During the Neotethyan Subduction System

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-ocean ridge

Journal of the Geological Society

Numerical simulations and theoretical analyses predict that forearc ophiolites probably record th... more Numerical simulations and theoretical analyses predict that forearc ophiolites probably record the end of subduction followed by re-initiation. We report here the results of a field study and new geochronological data that enable identification of the Kermanshah forearc basin, SW Iran. This basin is filled with two terrestrial volcaniclastic successions separated by an Upper Cretaceous reef facies limestone. Early Late Cretaceous ocean island basalts, early Eocene incompatible element-enriched mid-ocean ridge basalts/normal-type mid-ocean ridge basalts and late Eocene arc basalts of the basin indicate that Neotethyan subduction ended during the early Late Cretaceous and then re-initiated during the late Eocene. We suggest that the Neotethyan Ocean between the Iranian and Arabian continents consisted of leading and trailing oceanic plates separated by a mid-ocean ridge (MOR). Subduction of the leading plate generated the Jurassic–Early Cretaceous Sanandaj–Sirjan arc, which was ended ...

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-ocean ridge

Journal of the Geological Society

Numerical simulations and theoretical analyses predict that forearc ophiolites probably record th... more Numerical simulations and theoretical analyses predict that forearc ophiolites probably record the end of subduction followed by re-initiation. We report here the results of a field study and new geochronological data that enable identification of the Kermanshah forearc basin, SW Iran. This basin is filled with two terrestrial volcaniclastic successions separated by an Upper Cretaceous reef facies limestone. Early Late Cretaceous ocean island basalts, early Eocene incompatible element-enriched mid-ocean ridge basalts/normal-type mid-ocean ridge basalts and late Eocene arc basalts of the basin indicate that Neotethyan subduction ended during the early Late Cretaceous and then re-initiated during the late Eocene. We suggest that the Neotethyan Ocean between the Iranian and Arabian continents consisted of leading and trailing oceanic plates separated by a mid-ocean ridge (MOR). Subduction of the leading plate generated the Jurassic–Early Cretaceous Sanandaj–Sirjan arc, which was ended ...

Research paper thumbnail of Multiple volcanic episodes of the Kermanshah forearc basin, SW Iran: a record of the deactivation and re-initiation of Neotethyan subduction involving a mid-ocean ridge

Journal of the Geological Society, Sep 8, 2022

Numerical simulations and theoretical analyses predict that forearc ophiolites probably record th... more Numerical simulations and theoretical analyses predict that forearc ophiolites probably record the end of subduction followed by re-initiation. We report here the results of a field study and new geochronological data that enable identification of the Kermanshah forearc basin, SW Iran. This basin is filled with two terrestrial volcaniclastic successions separated by an Upper Cretaceous reef facies limestone. Early Late Cretaceous ocean island basalts, early Eocene incompatible element-enriched mid-ocean ridge basalts/normal-type mid-ocean ridge basalts and late Eocene arc basalts of the basin indicate that Neotethyan subduction ended during the early Late Cretaceous and then re-initiated during the late Eocene. We suggest that the Neotethyan Ocean between the Iranian and Arabian continents consisted of leading and trailing oceanic plates separated by a mid-ocean ridge (MOR). Subduction of the leading plate generated the Jurassic–Early Cretaceous Sanandaj–Sirjan arc, which was ended by MOR–trench collision. The Zagros late Early Cretaceous forearc ophiolites represent the youngest/hottest segments of the leading plate emplaced during the MOR–trench collision. Subsequently, subduction of the MOR generated the forearc basin and basalts with diverse geochemistry. After c. 60 myr, the cooled trailing plate started to subduct, generating the late Eocene arc basalts. This model has significant implications for investigating and understanding other fossil subduction zones elsewhere in the world. Supplementary material: Supplementary material is available at https://doi.org/10.6084/m9.figshare.c.6086586

Research paper thumbnail of Rogenesis and U-PB Age Dating of Intrusive Bodies in the Sar Cheshmeh Deposit

فصلنامه علمی-پژوهشی علوم زمین, Dec 1, 2016

Research paper thumbnail of Post-Collisional Shoshonitic, C-type Adakitic and Lamprophyric Plutonism in the Khankandi Pluton, Arasbaran (NW Iran)

فصلنامه علمی علوم زمین, Feb 20, 2011

Research paper thumbnail of Geochemistry, Origin and Geodynamic Environment Intrusion Zaker-Sorkheh Dizaj in the Southern Limb of the Tarom Subzone, East of Zanjan

Research paper thumbnail of Petrogenesis of NW of Bam Volcanic Rocks

Research paper thumbnail of Petrology and Petro Genesis of Alkaline and Calc-Alkaline Lamprophyres in the NW Iran

فصلنامه علمی-پژوهشی علوم زمین, Mar 1, 2015

Research paper thumbnail of Ore mineralogy and geochemistry of the productive intrusive bodies in Guydash Fe-Skarn deposit, East Azarbaijan Province

Iranian Journal of Crystallography and Mineralogy

Research paper thumbnail of Geochemistry, Petrogenesis and dating of lamprophyric dykes in the Kaleybar area, NW Iran

Iranian Journal of Crystallography and Mineralogy

Research paper thumbnail of Latest Oligocene adakitic rocks in western Iran: implications for early crustal thickening and tectonic evolution of the Iran Block

Journal of the Geological Society

Adakitic rocks occur in a variety of tectonic settings and are key to understanding the tectonic ... more Adakitic rocks occur in a variety of tectonic settings and are key to understanding the tectonic evolution and geodynamics of orogenic belts. We investigated latest Oligocene (23.5–22.5 Ma) quartz monzonites and granites from the western segment of the Urumieh–Dokhtar magmatic belt in Iran, which are likely to have formed in response to the early stages of Arabia–Eurasia collision. The studied rocks have the geochemical characteristics of typical adakites, such as high SiO 2 (60.18–68.82 wt%) and Sr (499–793 ppm) contents, low Y (8.90–17.1 ppm) and Yb (0.88–1.58 ppm) contents, and high Sr/Y (26.1‒67.8) and (La/Yb) N (21.9‒32.9) ratios. They have variable K 2 O (3.88–5.09 wt%), MgO (0.44–2.74 wt%; Mg# = 33.7–52.5), Cr (4.27–40.59 ppm), Ni (4.28–35.68 ppm) and Th (9.56–59.59 ppm) contents, and relatively depleted Sr–Nd isotopic compositions [( 87 Sr/ 86 Sr) i = 0.70450–0.70516; ε Nd ( t ) = 2.1–2.7]. These characteristics indicate that the quartz monzonites were derived from the part...

Research paper thumbnail of Zircon Hf isotope of Iranian porphyry copper deposits: Constraints on the source of porphyry Cu magma

Petrology, 2016

In this research, zircon Hf isotopic ratios from Sungun, Sar Cheshmeh, Meiduk, Darreh Zar and Bon... more In this research, zircon Hf isotopic ratios from Sungun, Sar Cheshmeh, Meiduk, Darreh Zar and Bondar Hoza porphyry mineralized intrusions has been studied. The Hf isotopic ratios in the studied porphyry intrusions are similar and the average of zircon eHf values from Sar Cheshmeh, Meiduk, Darreh Zar, Bondar Hanza and Sungun porphyry intrusions are +8.2, +9.3, +9.2, +10 and +8.6, respectively. Also, the averages of zircon TDMC ages from the Sar Cheshmeh, Sungun, Meiduk, Darreh Zar and Bondar Hanza porphyry intrusions are 573, 550, 502, 510 and 464, respectively. The positive and restricted eHf values in the studied porphyry intrusion zircons along with the lack of inherited zircons shows continental crust did not contribute in the evolution of the porphyry magmas. The eHf in the studied zircons is between depleted mantle and lower crust values with a tendency towards the depleted mantle. According to adakitic nature of studied porphyry intrusions, post collisional tectonomagmatic set...

Research paper thumbnail of Petrological and isotopic study of basaltic rocks of Barzand area and comparison with Poshtasar originat basalts in South of Germi

Petrology, 2019

basaltic rocks in Barzand area (Continue to Kousmalyn basaltic rocks in Iran) show parallel trend... more basaltic rocks in Barzand area (Continue to Kousmalyn basaltic rocks in Iran) show parallel trend with Poshtasar basalt and they have older age according to stratigraphy in comparison with Poshtasar basalts. These basalts whit prismatic structure mostly have mugearitic composition and show hyalomicroporphyritic and glomeroporphyritic textures. The main minerals are Ca-rich plagioclase and diopsidic clinopyroxenes. Leucites generally have been altered to analcime. The parent magma of these rocks has a potassic and shoshonitic nature. In multi- element diagrams Ta, Ti and Nb show depletion and LILE, LREE have enrichment that suggests their primary magma have been originated from a subduction related mantle source. According to radiogenic isotopic ratios, mantle source of Barzand basaltic rocks have been drived from a fertilized mantle source during 0.8 to 0.9 billion years ago. According to initial 87Sr/86Sr (0.70499 ± 0.0004) and initial 143Nd/144Nd ratios (0.5127 ± 0.0004) estimated...

Research paper thumbnail of Geochemistry and petrogenesis of Eocene shoshonitic ‎and adakitic volcanic rocks in Sonajeel area ‎(Southeast of Heris, Eastern Azerbaijan)‎

Petrology, 2018

The studied area is located in the SE of Heris (Eastern Azerbaijan province) and the Alborz-Azerb... more The studied area is located in the SE of Heris (Eastern Azerbaijan province) and the Alborz-Azerbaijan structural zone. The Eocene volcanic rocks in the area of under study show various compositions ranging from olivine basalt, hornblende basalt, basaltic andesite and andesite to trachy andesite. The studied basaltic rocks, except for amphibole types, which show calc-alkaline affinity, mainly have shoshonitic and the andesitic rocks are adakitic composition. According to primitive mantle and chondrite normalized spider and REE diagrams, the studied rocks are characterized by LILE and LREE enrichment and pronounced depletion in HFS elements. Based on geochemical data the basaltic rocks have been originated from different degrees partial melting of a heterogeneous lithospheric mantle that metasomatized by subduction agents. The adakitic rocks have been generated from partial melting of thickened potassic mafic lower crust that have been metamorphosed in eclogitic facies.

Research paper thumbnail of Two plutonic complexes of the Sanandaj-Sirjan magmatic-metamorphic belt record Jurassic to Early Cretaceous subduction of an old Neotethys beneath the Iran microplate

Gondwana Research, 2018

Abstract The Neotethyan tectonics of the Zagros orogenic belt, SW Iran remains still hotly debate... more Abstract The Neotethyan tectonics of the Zagros orogenic belt, SW Iran remains still hotly debated in comparing with its western counterparts. One major issue concerns the timing and nature of the Sanandaj-Sirjan magmatic-metamorphic belt (SSMB), which is made predominantly of metamorphic rocks and Jurassic to Early Cretaceous large plutonic complexes. The Alvand and Qory are two largest plutonic complexes locating in north-central and southern segments, respectively, of the SSMB. Careful LA-ICP-MS U/Pb analyses of the magmatic zircons from the Alvand plutonic complex reveal a smooth spectra, along which the concordant age increase gradually from 120 to 190 Ma; while that of Qory is step-like consisting of two stages, a Jurassic and a late Early Cretaceous ones, respectively. New geochemical data, combined with zircon Lu/Hf results suggest that (1) the Alvand granitoids mostly resulted from a long-lived, successive injection of juvenile-crust-sourced magma batches without obvious fractionation crystallization (FC); but (2) the two stages granitoids of the Qory complex both generated by FC of juvenile-crust-sourced magmas; and (3) the gabbros of the Alvand complex are geochemically of E-MORB-affinity while those of the Qory complex are typical continental arc mafic rocks. Previously published petrological and 40Ar/39Ar data have identified a broken, Jurassic to Early Cretaceous high-pressure metamorphic belt to the southwest of the SSMB, which likely represents the closed, southeastern equivalent of the northern Neotethyan Ocean, north of the Taurides-Anatolia-Armenia block. Thus, the SSMB in Iran, the Kapan belt in Caucasus, and the Serbo-Macedonian belt in northern Turkey form a huge Jurassic to Early Cretaceous continental margin arc system recording northeastwards subduction of the older Northern Neotethyan Ocean beneath Eurasia. The Albian-Cenomanian ophiolites such as Koy, Kermanshah, and Neyriz in Iran represent the eastern counterpart of the younger Southern Neotethyan Ocean, south of the Taurides-Anatolia-Armenia block. During the subduction of the Old Neotethys, an intraplate transform fault likely opened and generated a slab-window beneath the Alvand region, which provided a constant energy source to steadily heat the low crust. This model satisfactorily interprets the unusual geochronological framework and geochemistry of the Alvand complex.

Research paper thumbnail of Geological, Alteration and Mineralization Characteristics of Ali Javad Porphyry Cu-Au Deposit, Arasbaran Zone, NW Iran

Open Journal of Geology, 2016

Research paper thumbnail of Post-collisional monzonitic magmatism from the Zagros hinterland. Implications on lithospheric processes

Research paper thumbnail of Geochemistry, Sr–Nd–Pb isotopes and geochronology of amphibole- and mica-bearing lamprophyres in northwestern Iran: Implications for mantle wedge heterogeneity in a palaeo-subduction zone