University of IsfahanPetrological Journal2228-521011320201121the origin of Abgarm ultramafic complex
(South of Kerman province)the origin of Abgarm ultramafic complex
(South of Kerman province)1202490510.22108/ijp.2020.122663.1174FARaziyehAlipourDepartment of Geology, Shahid Bahonar University, Kerman, IranHesamMoeinzadehShahid Bahonar university of KermanHamidAhmadipourShahid Bahonar UniversityJournal Article20200423Abgarm ultramafic complex in the south of Kerman province is a part of Esfandagheh- Haji Abad ophiolite which is located in the northern edge of Zagros thrust. The complex contains harzburgites, lherzolites, dunites, and chromitites. Harzburgite is the main lithology of Abgarm peridotites and dunites containing lens-shaped chromites are arranged in irregular layers between them. Some evidence such as recrystallization of grain boundaries, curved shapes boundaries, and exsolution lamellae of clinopyroxenes in orthopyroxenes in the harzburgites and lherzolite show that the peridotites of this studied complex, passed the high-temperature deformation in the upper mantle and then they have emplaced in the crust. Petrography and mineral chemistry evidence shows that there are two groups of chrome spinel in Abgarm complex. The first group is the disseminated chrome spinels in the peridotites and the other group is the chrome spinels in dunites and chromitites. Chemical analyses of spinels in studied rocks show that in these crystals the maximum amounts of Cr# belong to those that exist in the dunites and chromitites (60.76 – 63.81) and the minimum is for those in the lherzolites (11 – 13.50). Chemical composition of chrome spinels from the harzburgites and lherzolites are similar to those exist in Alpine peridotites with about 5 to 15% partial melting and probably they were formed in a back-arc basin environment while the dunites and chromitites of the complex can be caused by the reaction of the basaltic melts of the back-arc basin with peridotites.Abgarm ultramafic complex in the south of Kerman province is a part of Esfandagheh- Haji Abad ophiolite which is located in the northern edge of Zagros thrust. The complex contains harzburgites, lherzolites, dunites, and chromitites. Harzburgite is the main lithology of Abgarm peridotites and dunites containing lens-shaped chromites are arranged in irregular layers between them. Some evidence such as recrystallization of grain boundaries, curved shapes boundaries, and exsolution lamellae of clinopyroxenes in orthopyroxenes in the harzburgites and lherzolite show that the peridotites of this studied complex, passed the high-temperature deformation in the upper mantle and then they have emplaced in the crust. Petrography and mineral chemistry evidence shows that there are two groups of chrome spinel in Abgarm complex. The first group is the disseminated chrome spinels in the peridotites and the other group is the chrome spinels in dunites and chromitites. Chemical analyses of spinels in studied rocks show that in these crystals the maximum amounts of Cr# belong to those that exist in the dunites and chromitites (60.76 – 63.81) and the minimum is for those in the lherzolites (11 – 13.50). Chemical composition of chrome spinels from the harzburgites and lherzolites are similar to those exist in Alpine peridotites with about 5 to 15% partial melting and probably they were formed in a back-arc basin environment while the dunites and chromitites of the complex can be caused by the reaction of the basaltic melts of the back-arc basin with peridotites.https://ijp.ui.ac.ir/article_24905_17da74b79ffa50e09ccd174dbcc5327b.pdfUniversity of IsfahanPetrological Journal2228-521011320201121Geochemistry and Petrogenesis of
Carboniferous volcanic rocks, NW Marand:
Evidence for interacontinental rift Magmatism)Geochemistry and Petrogenesis of
Carboniferous volcanic rocks, NW Marand:
Evidence for interacontinental rift Magmatism)21402497110.22108/ijp.2020.122485.1173FAZahraBadrzadehDepartment of Geology, Payame Noor Universtiy, PO BOX 19395-3697, Tehran, IranMehrajAghazadehDepartment of Geology, Payame noor university,, Tehran-IranSaharFathiDepartment of Geology, Payame Noor Universtiy, IranJournal Article20200419The studied volcanic-sedimentary sequence located at the East-Azarbaijan province, north Marand and in the Central Iranian structural zone. The studied sequence composed of alternative sandstone, shale, conglomerate, limestone, felsic volcaniclastics, alkalibasalt and rhyolite which outcropped below the Permian sedimentary sequence and on the Devonian sedimentary rocks. Magmatism in the area has a bimodal magmatic characteristic and the basaltic rocks have alkaline affinity. They are characterized by enrichment of LILE over HFSE and show significant OIB-type trace element signatures. On the basis of trace element data, the basic rocks generated by low degree partial melting of garnet-spinel lherzolite mantle source with ocean island basalt characteristics, which fractionated en route to the surface. On the basis of geological and major and trace elements data, the felsic rocks are comparable to A-type granitoids and their trace element ratios are very close to determinate bulk continental crust composition which indicate their crustal origin. The felsic rocks were originated by the dehydration melting of a tonalite or granodiorite source with a plagioclase rich residual assemblage. The Carboniferous bimodal volcanism were induced by continental rifting and asthenospheric upwelling during early phases of Neotethys opening.
The studied volcanic-sedimentary sequence located at the East-Azarbaijan province, north Marand and in the Central Iranian structural zone. The studied sequence composed of alternative sandstone, shale, conglomerate, limestone, felsic volcaniclastics, alkalibasalt and rhyolite which outcropped below the Permian sedimentary sequence and on the Devonian sedimentary rocks. Magmatism in the area has a bimodal magmatic characteristic and the basaltic rocks have alkaline affinity. They are characterized by enrichment of LILE over HFSE and show significant OIB-type trace element signatures. On the basis of trace element data, the basic rocks generated by low degree partial melting of garnet-spinel lherzolite mantle source with ocean island basalt characteristics, which fractionated en route to the surface. On the basis of geological and major and trace elements data, the felsic rocks are comparable to A-type granitoids and their trace element ratios are very close to determinate bulk continental crust composition which indicate their crustal origin. The felsic rocks were originated by the dehydration melting of a tonalite or granodiorite source with a plagioclase rich residual assemblage. The Carboniferous bimodal volcanism were induced by continental rifting and asthenospheric upwelling during early phases of Neotethys opening.
https://ijp.ui.ac.ir/article_24971_38d81b8494fed0d03fc65e7c7f35f572.pdfUniversity of IsfahanPetrological Journal2228-521011320201121Geology, petrography and geochemistry of
volcanic rocks and granitoid intrusions in
Churan gold and copper deposit (northeast Sirjan)Geology, petrography and geochemistry of
volcanic rocks and granitoid intrusions in
Churan gold and copper deposit (northeast Sirjan)41642496010.22108/ijp.2020.123297.1183FAAliShahabinejadDepartment of Economic Geology, Tarbiat Modares University, Tehran, IranHossein AliTajeddinDepartment of Geology, Faculty of Basic Sciences, Tarbiat Modarres University, Tehran, IranSeyed AhmadMeshkaniZarmesh Mining and Commercial Group, Tehran, IranMehdiMovahedniaDepartment of Geology, Faculty of Basic Sciences, Tarbiat Modarres University, Tehran, Iran0000-0002-9088-4369Journal Article20200601The Churan gold and copper deposit located 70 km northeast of Sirjan in the Dehaj-Sarduyeh structural subzone of the Urumieh -Dokhtar magmatic arc. Lithologically, the area mainly consists of the Middle Eocene volcanic rocks with dominant andesite to andesite-basalt crosscutting by the intrusive rocks and quartz dioritic to granodioritic dykes belonging to the Oligocene-Miocene time. The host granitoid rocks are classified as meta-aluminous I-type granitoid with high potassium calc-alkaline affinity dominated by plagioclase, biotite, hornblende, alkali feldspar, quartz and apatite, zircon, and opaque as accessory minerals. The rocks under study are characterized by large ion lithophile element (LILE) enrichment, high field strength element (HFSE) depletion, and high LREE/HREE ratios. On tectonomagmatic discrimination diagrams, the Churun granitoids are scattered on active continental margins to post-collisional fields. Mineralization occurred as gold and copper-bearing quartz vein and veinlets in the quartz diorite intrusive. Hydrothermal alterations associated with the mineralization contain silicification, sulfidation, tourmalinization, and sericitization. Ore mineral assemblages in the deposit consist of pyrite, arsenopyrite, chalcopyrite, bornite, sphalerite, galena, covellite, malachite, and iron hydroxides. The mineralization criteria as well as the spatial relationship between ore-bearing veins and alteration zones granite-granodiorite intrusion suggest that gold mineralization in the investigated area is related to granite-granodiorite emplacement and likely originated from those rocks.The Churan gold and copper deposit located 70 km northeast of Sirjan in the Dehaj-Sarduyeh structural subzone of the Urumieh -Dokhtar magmatic arc. Lithologically, the area mainly consists of the Middle Eocene volcanic rocks with dominant andesite to andesite-basalt crosscutting by the intrusive rocks and quartz dioritic to granodioritic dykes belonging to the Oligocene-Miocene time. The host granitoid rocks are classified as meta-aluminous I-type granitoid with high potassium calc-alkaline affinity dominated by plagioclase, biotite, hornblende, alkali feldspar, quartz and apatite, zircon, and opaque as accessory minerals. The rocks under study are characterized by large ion lithophile element (LILE) enrichment, high field strength element (HFSE) depletion, and high LREE/HREE ratios. On tectonomagmatic discrimination diagrams, the Churun granitoids are scattered on active continental margins to post-collisional fields. Mineralization occurred as gold and copper-bearing quartz vein and veinlets in the quartz diorite intrusive. Hydrothermal alterations associated with the mineralization contain silicification, sulfidation, tourmalinization, and sericitization. Ore mineral assemblages in the deposit consist of pyrite, arsenopyrite, chalcopyrite, bornite, sphalerite, galena, covellite, malachite, and iron hydroxides. The mineralization criteria as well as the spatial relationship between ore-bearing veins and alteration zones granite-granodiorite intrusion suggest that gold mineralization in the investigated area is related to granite-granodiorite emplacement and likely originated from those rocks.https://ijp.ui.ac.ir/article_24960_7105968c8469a403e47e4196dec799c6.pdfUniversity of IsfahanPetrological Journal2228-521011320201121Spatial- temporal relationship of mineralization and magmatism in the Mazraeh polymetallic deposit
(north of Ahar, Eastern Azarbaijan province)Spatial- temporal relationship of mineralization and magmatism in the Mazraeh polymetallic deposit
(north of Ahar, Eastern Azarbaijan province)65842495810.22108/ijp.2020.124073.1192FAHemayatJamaliاصفهان، دانشگاه اصفهان، گروه زمین شناسیJournal Article20200721The Sheyvar-Dagh batholith, one of the most important intrusive bodies in northwest Iran, intruded the Upper Cretaceous and the Eocene volcano-sedimentary sequences and associated with some Cu- Fe (±W±Au) mineralization. The Sheyvar-Dagh batholith consists of different phases of magmatism (33- 10Ma) with different compositions and geochemical features. The oldest phases (Oligocene) with granite, granodiorite, syenite, and gabbro composition are dominated by plagioclase and alkali- feldspar as phenocrysts which is indicative of low water content in their parent magma, therefore, they are not associated with any mineralization. While, the younger magmatic phases (Miocene) with overall quartz monzonitic composition and amphibole- biotite phenocrysts show adakitic signature with more water content (>4% H<sub>2</sub>O). The younger magmatism shows a close temporal-spatial relationship with a variety of ore mineralization. So, this can be used as an exploration key in the Sheyvar-Dagh region. In the Mazraeh area, mineralization has occurred in two forms massive (skarn) and veinlet-disseminated (intrusion- related). Skarn mineralization, which mainly consists of garnet, epidote, magnetite, pyrite, and chalcopyrite, occurred in the Upper Cretaceous limestones, while veinlet-disseminated mineralization occurred in both the Miocene subvolcanic and the Oligocene coarse-grained bodies, and is associated with weak potassic and phyllic alterations.
The Sheyvar-Dagh batholith, one of the most important intrusive bodies in northwest Iran, intruded the Upper Cretaceous and the Eocene volcano-sedimentary sequences and associated with some Cu- Fe (±W±Au) mineralization. The Sheyvar-Dagh batholith consists of different phases of magmatism (33- 10Ma) with different compositions and geochemical features. The oldest phases (Oligocene) with granite, granodiorite, syenite, and gabbro composition are dominated by plagioclase and alkali- feldspar as phenocrysts which is indicative of low water content in their parent magma, therefore, they are not associated with any mineralization. While, the younger magmatic phases (Miocene) with overall quartz monzonitic composition and amphibole- biotite phenocrysts show adakitic signature with more water content (>4% H<sub>2</sub>O). The younger magmatism shows a close temporal-spatial relationship with a variety of ore mineralization. So, this can be used as an exploration key in the Sheyvar-Dagh region. In the Mazraeh area, mineralization has occurred in two forms massive (skarn) and veinlet-disseminated (intrusion- related). Skarn mineralization, which mainly consists of garnet, epidote, magnetite, pyrite, and chalcopyrite, occurred in the Upper Cretaceous limestones, while veinlet-disseminated mineralization occurred in both the Miocene subvolcanic and the Oligocene coarse-grained bodies, and is associated with weak potassic and phyllic alterations.
https://ijp.ui.ac.ir/article_24958_70d5eae0d936222ab81c8785fa148149.pdfUniversity of IsfahanPetrological Journal2228-521011320201121Geochemistry and petrogenesis of south Qorveh A-type granitoids (northwest of Sanandaj- Sirjan zone): An evidence for active continental margin tensional tectonicGeochemistry and petrogenesis of south Qorveh A-type granitoids (northwest of Sanandaj- Sirjan zone): An evidence for active continental margin tensional tectonic851102557110.22108/ijp.2020.123500.1186FAMajidShirmohammadiDepartment of Geology/Faculty of Sciences/ Bu- Ali Sina University/Hamedan/IranAli AsgharSepahi Gerowدانشگاه بوعلی سیناMohammadMaanijouBu-Ali Sina UniversityAshrafTourkianDepartment of Geology, Faculty of sciences, Bu-Ali Sina University, Hamedan, IranJournal Article20200628The studied area (Galali- Varmaqan) located at the northern part of the Sanandaj- Sirjan zone, south of the Qorveh city. The granitic rocks are dominated by quartz, alkali- feldspar and plagioclase. Amphibole and biotite are the most important mafic minerals, apatite, sphene, zircon and Fe- oxides are the accessories. The Galai- Varmaqan granitoids show geochemical characteristics of metaluminous A-type granites with mainly shoshonitic and high- K calc- alkaline affinity. Based on geotectonic diagrams, these rocks are mostly clusterred at the volcanic arc granites (VAG) and within plate granites (WPG) fields which points to their formation in a post- orogenic magmatic system. LILEs and HFSEs enrichment indicates the existence of a crustal source for the studied granites and formation of the parent magma at the stability field of plagioclase in the lack of garnet. In this study, we suggest that the A-type granites have been formed by partial melting of lower crust charnokitic rocks. The A-type granites are related to extensional magmatism of the Neo- Tethys oceanic crust beneath the Central Iranian microcontinent, due to roll- back of subducting slab. Thus, change of tectonic regime from compressional to tensional in the late- Jurassic to early- Cretaceous time (probably in a pull-apart basin tectonic setting), is suggested for the formation of A-type granites in this region of the Sanandaj- Sirjan zone.
The studied area (Galali- Varmaqan) located at the northern part of the Sanandaj- Sirjan zone, south of the Qorveh city. The granitic rocks are dominated by quartz, alkali- feldspar and plagioclase. Amphibole and biotite are the most important mafic minerals, apatite, sphene, zircon and Fe- oxides are the accessories. The Galai- Varmaqan granitoids show geochemical characteristics of metaluminous A-type granites with mainly shoshonitic and high- K calc- alkaline affinity. Based on geotectonic diagrams, these rocks are mostly clusterred at the volcanic arc granites (VAG) and within plate granites (WPG) fields which points to their formation in a post- orogenic magmatic system. LILEs and HFSEs enrichment indicates the existence of a crustal source for the studied granites and formation of the parent magma at the stability field of plagioclase in the lack of garnet. In this study, we suggest that the A-type granites have been formed by partial melting of lower crust charnokitic rocks. The A-type granites are related to extensional magmatism of the Neo- Tethys oceanic crust beneath the Central Iranian microcontinent, due to roll- back of subducting slab. Thus, change of tectonic regime from compressional to tensional in the late- Jurassic to early- Cretaceous time (probably in a pull-apart basin tectonic setting), is suggested for the formation of A-type granites in this region of the Sanandaj- Sirjan zone.
https://ijp.ui.ac.ir/article_25571_8d5126da0727c7e926d8266d9c3d0079.pdfUniversity of IsfahanPetrological Journal2228-521011320201121Petrography, geochemistry
and tectonic setting of mafic- ultramafic intrusion
in the Bafq 15th anomaly (Iron) (Central Iran)Petrography, geochemistry
and tectonic setting of mafic- ultramafic intrusion
in the Bafq 15th anomaly (Iron) (Central Iran)1111282514510.22108/ijp.2020.123179.1178FASakineAmraeiPhD student of economic geology, Department of Inorganic Geology and Water, Faculty of Earth sciences, Shahid Beheshti University, Tehran, IranMehrdadBehzadiAssociate professor, Department of Inorganic Geology and Water, Faculty of Earth sciences, Shahid Beheshti University, Tehran, Iran0009-0002-5154-3550MohammadYazdiProfessor, Department of Inorganic Geology and Water, Faculty of Earth sciences, Shahid Beheshti University, Tehran, IranJournal Article20200601The mafic- ultramafic intrusion in the Bafq anomaly Iron located 35 Km northwest of Bafq city, Central Iran. The 15<sup>th</sup> anomaly intrusion intruded the Rizu sequence series, stratigraphically attributed to early Cambrian magmatism in the west of Posht-e- Badam block. The Rizu sequence series is composed of carbonate rocks of upper Neo-Proterozoic-early Cambrian. The mafic-ultramafic intrusion is dominated by amphibole-gabbro, apatite- gabbro, anorthosite- gabbro, amphibole- pyroxenite, apatite-pyroxenite with predominant granular texture and cumulate characteristics. The associated main mineral assemblage composed of cumulate predominantly clino-pyroxene, Fe-Ti oxides, calcic plagioclase, amphibole, apatite, as well as minor olivine. The intrusion formed from mafic magma and differentiated from tholeiitic to weakly calc-alkaline affinity. Spider diagrams of the analyzed samples were normalized to the standard values of chondrite and primitive mantle. REE– normalized diagrams are characterized by LILEs enrichment and HFSEs depletion and mild negative REEs trend. Different tectonic setting discriminative diagrams and elemental ratios are indication of a subduction related affinity. The parental magma could be generated by melting of mantle peridotites (lithospheric mantle) which previously affected by subduction related fluids. The results of this research is consistent with the previous models which considered the Early Cambrian magmatism in Post-e-Badam block related to the subduction of Proto- Tethys oceanic crust beneath the Central Iran in the north of Gondwana land.
<strong> </strong>The mafic- ultramafic intrusion in the Bafq anomaly Iron located 35 Km northwest of Bafq city, Central Iran. The 15<sup>th</sup> anomaly intrusion intruded the Rizu sequence series, stratigraphically attributed to early Cambrian magmatism in the west of Posht-e- Badam block. The Rizu sequence series is composed of carbonate rocks of upper Neo-Proterozoic-early Cambrian. The mafic-ultramafic intrusion is dominated by amphibole-gabbro, apatite- gabbro, anorthosite- gabbro, amphibole- pyroxenite, apatite-pyroxenite with predominant granular texture and cumulate characteristics. The associated main mineral assemblage composed of cumulate predominantly clino-pyroxene, Fe-Ti oxides, calcic plagioclase, amphibole, apatite, as well as minor olivine. The intrusion formed from mafic magma and differentiated from tholeiitic to weakly calc-alkaline affinity. Spider diagrams of the analyzed samples were normalized to the standard values of chondrite and primitive mantle. REE– normalized diagrams are characterized by LILEs enrichment and HFSEs depletion and mild negative REEs trend. Different tectonic setting discriminative diagrams and elemental ratios are indication of a subduction related affinity. The parental magma could be generated by melting of mantle peridotites (lithospheric mantle) which previously affected by subduction related fluids. The results of this research is consistent with the previous models which considered the Early Cambrian magmatism in Post-e-Badam block related to the subduction of Proto- Tethys oceanic crust beneath the Central Iran in the north of Gondwana land.
<strong> </strong>https://ijp.ui.ac.ir/article_25145_913b37e9c3a948783c144b42bf02fae5.pdf