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Introduction Granites are interesting because of their abundance in the continental crust and the presentation of valuable information from the depths of the earth and their close dependence on tectonic and geodynamic processes (Bonin, 2007). The Mishu granites are exposed over an area around 50 km2 in the northwestern Iran near the city of Tabriz (Figures 1 and Figures 2). The Mishu granites have been injected into the Neoproterozoic shales, carbonates, sandstones, and tuffs of the Kahar Formation (Asadian et al. 1994). Mafic and ultramafic rocks (gabbro, basalt, and dunite) occur at the north and northeast of the Mishu granites and seem to be the host of granites. Field observations show a magmatic injection of the Mishu granites into the mafic-ultramafic rocks. There are several outcrops of granite rocks in the northwest Iran, including Takab–Zanjan, Khoy, Soursat, and Mishu. Among these outcrops, there are no systematic geochemical and geochronological studies on the Mishu rocks. In this paper, we investigate the genetic relationship between different parts of the mass, origin of the constructive magma and the tectonic position of this intrusion with the help of the results of field studies governing different parts of the Harris intrusion mass, petrography and geochemical analysis of the main and rare elements. Material and methods A total of 150 samples were collected from Mishu granites. Polished thin sections were prepared from all the collected samples. Based on petrographic observations, 20 samples with minimal effects of hydrothermal alteration were selected for whole-rock geochemical analysis (Table 1). These selected samples were analyzed for major and trace elements at the ACME Laboratory (in the ACME Analytical Laboratories of Vancouver, Canada). Analytical errors for major elements are assessed as

The Marivan region located in the west of Kurdistan province, northwest of Iran and in the structural geological divisions of Iran (Stöcklin and Nabavi, 1973). The Mesozoic volcanic rocks are widespread in the Northern Sanandaj- Sirjan zone in comparison to the central and southern parts of this zone. The basic term of this volcanic belt with a calc-alkaline tendency is dominant where was formed in association with the Sanandaj-Sirjan arc magmatism in the Mesozoic which generated as a result of the subduction of the Neotethys oceanic crust under the active continental margin of Central Iran (Omrani et al., 2008; Azizi and Jahangiri, 2008; Moinevaziri et al., 2015). The studied area located in the Sanandaj Cretaceous volcanic belt (SVB) (Azizi and Moinevaziri, 2009), is characterized by the presence of basalts and andesite-basalts, often intruded shales, sandstones, and Cretaceous limestones. Rahimzadeh et al. (2021) investigated the North of Sanandaj-Sirjan magmatism in two basic and acidic phases and attributed their formation to a continental arc tectonic environment with extension. Also, the general age of the North Sanandaj-Sirjan zone magmatism varies from 110 to 130 million years (Barmian-Aptian). Ali et al. (2016) determined a bimodal model for the volcanic rocks of the Kata-rash region in Iraq Kurdistan (north of the study area), which originated 108 Ma (Albian) in an oceanic arc tectonic environment. The main purpose of the present paper is to study the petrology and geochemistry of the volcanic rocks of the area, in order to determine their tectonic setting. Regional Geology The The studied area is located in the north and east of Marivan city and is a part of the 1:100,000 geological map of Marivan (Sabzehi et al., 2009). Structurally, it is located in the northwestern part of Sanandaj-Sirjan zone. The rock units with Albian age, are a sequence of low metamorphosed volcanic-sedimentary rocks and consist of basaltic lavas, andesite-basalt, rhyodacite, pyroclastic, shale, calcareous shale, metamorphosed limestone, sandstone and minor amounts of conglomerate. A great volume of basic rocks is found in the north of Marivan while the acidic domes are seen in the east of the Marivan. The field relationships of volcano-sedimentary sequence indicates that the volcanic rocks erupted from deep to shallow marine environment (Rahimzadeh et al., 2021). Research method Eleven samples selected from the Marivan volcanic rocks for chemical analyses. The major elements were measured by ICP-OES method and trace and rare earth elements (REE) were measured by the ICP-MS method in the Canadian MS-Analyses laboratory. Petrography Cretaceous volcanic rocks with bimodal composition are often basic to slightly intermediate and acidic outcrops. The basic phase includes a large amount of basalt and a small amount of basaltic andesite and the acidic phase is composed of rhyolite and rhyodacite. Porphyritic and microlithic-glassy are the common textures in the rocks under study. The presence of zoned-plagioclases, quartz with embayed texture in rhyodacite, regrowth in crystals margin in both basic and acidic phases indicate the chemical imbalance of phenocrysts with melt in the magma forming these rocks. Geochemistry Based on the results of chemical analyses, the Marivan volcanic rocks are classified as the basic and acidic where the bimodality of rocks can be seen. The basic rocks show calk-alkaline with tholeiitic tendency whereas the acidic term display the calc-alkaline nature. The geochemical results in the spider diagrams show that the basic rocks of the region are enriched in LREE and LILE (K, Cs and relatively Ba and Rb), and depleted in HFSE (Nb, Ti, P) except U and Th. The acidic rocks are enriched in LILE (K, Cs, Rb, Th) except Sr and depletion of HFSE (P, Ti, Nb) except U and Zr. Nb and Ti depletion is one of the characteristic features of magmatic arcs. Also, these rocks have an LREE-enriched pattern in both the basic and acidic phases with a high LREE/HREE ratio and a specific negative Eu anomaly are found only in the acidic phase. The acidic rocks were originated from the lherzolitic spinel mantle with a 5 to 8% partial melting degree whereas the basic phase is generated from the lherzolitic spinel-garnet mantle with 10 to 22% partial melting degree. Tectonic setting This volcanic complex is a part of the Sanandaj-Sirjan magmatic arc, which shows both subduction and extensional components. Extension in the continental arc happened relation to roll-back or slab collapse (Wei et al., 2017; Rahimzadeh et al., 2021). Rollback occurs as a result of its pressure, the subducting crust turns back and breaks, and extension occurs for a short period. So, in this geodynamic environment, bimodal volcanism can be happened where basic term show the tholeiitic affinity. It’s happened from continental arc position. In this tectonic setting environments, most of the volcanic rocks are basaltic rocks while in a typical continental arc such as the Andes arc and the Urumieh-Dokhtar abundant andesite rocks are widespread (Gill, 2010). Conclusion Marivan volcanic rocks are part of the northern Sanandaj-Sirjan zone continental arc, which is roll-back happened in the Albian and as a result occurred the local extension in the regional compression setting. Its signs include the presence of shales associated with volcanic rocks, the abundance of basalts over andesites, the tendency of calc-alkaline to tholeiitic nature in most of the basic rocks and as the several geodynamic diagrams display. However, the obvious evidence of subduction in the region can be seen as the depletion of Nb and Ti elements and enrichment of LILE and LREE compared to HFS elements. [ABSTRACT FROM AUTHOR]

The Harris granitoid body, as a part of Alborz-Azarbaijan zone, located in the northwestern Iran and west of Shabestar city. The intrusive body cut the Kahar formation and covered by non-conformably Permian sediments. This body is granite- alkali granite in composition with peraluminous to metaluminous nature. Granular and perthite are dominant textures of the studied samples. The rocks under investigated are marked by quartz, K-feldspar, plagioclase as well as biotite, amphibole, pyroxene, apatite, titanite and zircon as minor minerals. The strong Eu negative in the REE diagram points to either the presence of plagioclase in the source or differentiation process of the plagioclase during evolution of the parent magma. As the petrochemical data display, the studied rocks are A-type granitoids, and due to Nb poor, they are compatible with A2- type. In addition, Ba negative anomaly and Rb, Th enrichment relative to Ta and Nb represent the crustal origin of Harris intrusive body. In these granites, Ba shows more negative anomalies than post collision granites and the Zr, Ta, Nb and Yb amounts are somewhat higher than those of post collision granites. The Harris granite body can be regarded as intraplate and non-orogenic granites generated in a post collision tensile environment. Overall, the Harris granitoid possibly originated by partial melting of lower crust with tonalite-granodiorite composition.

The Harris granitoid body, as a part of Alborz-Azarbaijan zone, located in the northwestern Iran and west of Shabestar city. The intrusive body cut the Kahar formation and covered by non-conformably Permian sediments. This body is granite- alkali granite in composition with peraluminous to metaluminous nature. Granular and perthite are dominant textures of the studied samples. The rocks under investigated are marked by quartz, K-feldspar, plagioclase as well as biotite, amphibole, pyroxene, apatite, titanite and zircon as minor minerals. The strong Eu negative in the REE diagram points to either the presence of plagioclase in the source or differentiation process of the plagioclase during evolution of the parent magma. As the petrochemical data display, the studied rocks are A-type granitoids, and due to Nb poor, they are compatible with A2- type. In addition, Ba negative anomaly and Rb, Th enrichment relative to Ta and Nb represent the crustal origin of Harris intrusive body. In these granites, Ba shows more negative anomalies than post collision granites and the Zr, Ta, Nb and Yb amounts are somewhat higher than those of post collision granites. The Harris granite body can be regarded as intraplate and non-orogenic granites generated in a post collision tensile environment. Overall, the Harris granitoid possibly originated by partial melting of lower crust with tonalite-granodiorite composition. [ABSTRACT FROM AUTHOR]

The Tarom- Masuleh area (western Alborz) exposes considerable Late Paleozoic volcanic rocks. Stratigraphic relationships indicate that the igneous units are of Carboniferous- Permian age. Based on whole- rock chemical data, the samples are compositionally basic (SiO2= 45.3- 50.7 wt.%) and alkaline (TiO2= 1.1- 4.4 wt.%; Nb/Y=0.9- 2.3). Furthermore, these rocks are characterized by nearly primitive to evolved compositions (MgO= 14.5- 2.5 wt.%). Major and trace elements data show that chemical variations were predominantly controlled by crystal fractionation and, mantle source processes or crustal contamination was not so effective. Trace element theoretical modeling of crystallization process also shows that fractional crystallization of olivine + clinopyroxene has played a major role in the chemical evolution of the melt. The chemical characteristics of the samples in terms of HFSE enrichment and elevated LREE/HREE ratio ((La/Yb)N= 4.8- 17.5) are identical to those of oceanic island basalts (OIB). Thus, the Late Paleozoic magmatism of the Tarom-Masouleh region took place in an intraplate setting (passive continental margin) influenced by the extensional tectonic regime. Coeval magmatism in other parts of Iran, including Central Iran, Sanandaj- Sirjan and Azerbaijan, as well as other areas of the northern margin of Gondwana (Oman, North Africa) and China, similarly represent intraplate magmatic signature attributed to the mantle plume and/or hot spot activity or extensional tectonics and rifting concurrent with the early stages of the appearance of the Neotethys Ocean. [ABSTRACT FROM AUTHOR]

In the north east of Tehran province and in the Central Alborz zone, a thick basaltic horizon occurs at the boundary of Jeiroud and Mobarak Formations near the Jeiroud village and Darbandsar and Garmabdar areas, indicating a nonconformity boundary of Devonian- Carboniferous in this region. The rock horizon comprises basalt, trachybasalt and trachyandesite representing dominantly porphyry texture and diabase as feeding dike with ophitic and subophitic textures; all displaying alkaline sodic nature. Both Chondrite- normalized rare earth element (REE) patterns enriched in LREE with respect to HREE and normalized to primitive mantle spider diagram are similar to those of oceanic island basalts (OIB). The studied samples plot in within plate basaltic field in the tectonic discrimination diagrams of basalts. Trace element and some major element contents show low degree partial melting (< 10%) of a deep (90- 110 km) garnetbearing mantle source. As the basaltic samples of Garmabdar area geochemically show intra- plate tectonomagmatic setting it seems that during the late Devonian (and earlier times), Alborz has been as a passive continental margin in the southern border of Paleo- Tethys and its magmatism was more probably affected by extensional tectonism or mantle plume activity related to earlier stages of Neo- Tethys ocean development. [ABSTRACT FROM AUTHOR]

In north and northwest of Garmsar in Semnan province, some basic igneous rocks with the Oligocene age outcropped as dyke, sill and very small stocks in the Lower Red Formation. These rocks have basic composition and alkaline nature. They show various textures such as porphyric, glomeroporphyric, ophitic, subophitic, intergranular and granular. Plagioclase and clinopyroxene as the main minerals, olivine, opaque (magnetite, titanomagnetite), apatite and phelogopite as the minor minerals and chlorite, prehnite, epidote, serpentine sericite and calcite are the secondary minerals in these rocks. Primitive mantle and chondrite normalized diagrams of these rocks show strong enrichments in light rare earth elements (LREEs) and relative depletions in heavy rare earth elements (HREEs). Also, parallel trends of the samples in these diagrams indicate a common source for these rocks and the role of the differentiation crystallization in their genesis. Investigated rocks are plotted in back-arc basin setting field in discrimination tectonic diagrams. Geochemical studies show magma forming of these rocks have been formed from 11- 16% partial melting of an enriched modified garnet lherzolitic mantle source in 90-100 km depths. This magma intruded via deep fractures and faults in the incipient extensional back-arc basin resulted from northward subduction of Arabian plate beneath the Central Iran in the Oligocene-Miocene time.

In north and northwest of Garmsar in Semnan province, some basic igneous rocks with the Oligocene age outcropped as dyke, sill and very small stocks in the Lower Red Formation. These rocks have basic composition and alkaline nature. They show various textures such as porphyric, glomeroporphyric, ophitic, subophitic, intergranular and granular. Plagioclase and clinopyroxene as the main minerals, olivine, opaque (magnetite, titanomagnetite), apatite and phelogopite as the minor minerals and chlorite, prehnite, epidote, serpentine sericite and calcite are the secondary minerals in these rocks. Primitive mantle and chondrite normalized diagrams of these rocks show strong enrichments in light rare earth elements (LREEs) and relative depletions in heavy rare earth elements (HREEs). Also, parallel trends of the samples in these diagrams indicate a common source for these rocks and the role of the differentiation crystallization in their genesis. Investigated rocks are plotted in back-arc basin setting field in discrimination tectonic diagrams. Geochemical studies show magma forming of these rocks have been formed from 11- 16% partial melting of an enriched modified garnet lherzolitic mantle source in 90-100 km depths. This magma intruded via deep fractures and faults in the incipient extensional back-arc basin resulted from northward subduction of Arabian plate beneath the Central Iran in the Oligocene-Miocene time. [ABSTRACT FROM AUTHOR]

Migmatites have formed an important part of high-grade metamorphism in the Boroujerd area aureole (north of Sanandaj-Sirjan zone). Migmatitic complex including: migmatites, schist migmatites and hornfelse migmatites with a different range of structural and mineralogical compositions. These rocks are observed as light (leucosome), dark (melanosome) and dark and light (mesosome). Leucosomes mainly composed from quartz, plagioclase, K-feldspar, biotite and muscovite and also have perthite, poikiloblastic, granoblastic, graphic and myrmekite textures. Melanosomes formed from minerals such as biotite, garnet, andalusite, tourmaline and sillimanite have lepidobalastic, porphyrolepidoblastic and lepidoporphyrobalastic textures. Mesosomes formed from dark and light minerals and show porphyroblastic, lepidoblastic and granoblastic textures. According to petrographic studies and whole rock chemical analyses for these rocks revealed that dominant protolith is pelitic rocks. The thermobarometry results showed temperature range of of 568°C to 662 °C and pressure of 2.8 to 3.3 kbars. According to the calculated temperature and pressure, the geothermal gradient of schist migmatites and hornfels migmatites determined 48 °C/km and 60 °C/km, respectively. Heat release of the Bourojerd pluton, mafic magmatism in area (that enclaves of them can be seen in the granitoids) and subduction fluid causes migmatites that it shows the main factor increasing geothermal gradient is the presence of hot igneous plutons and enter intrusion fluid in the magmatic arcs. [ABSTRACT FROM AUTHOR]

In this study, we investigate the geochemical evolution and the age of intrusive rocks from central part of the magmatic arc of the northeastern Iran in the south of Sabzevar (Khorasan Razavi province). The geochemical evidences point to magmatism related to volcanic arc and subduction zone. The intrusive rocks vary in composition from granite to diorite and gabbro. Based on mineralogy and the high values of magnetic susceptibility [(>400) x 10-5 SI], the intrusive rocks are classified as magnetite-series of oxidized I-type granitoid. Chemically, they are meta to per-aluminous, enriched in LILE (K, Th and Rb) and depleted in HFSE (Nb, P and Ti) and belong to tholeiitic series. Low (La/Yb)N, low Sr/Y ratios and the negative anomaly of Eu indicate a classic island arc type magmatism. Trace elements behavior in acidic and intermediate intrusive rocks show nearly flat pattern (La/SmPm =0.97-2.57) and lie outside the garnet stability field. Thus, the source rocks should not be eclogite or garnet amphibolite. The geochemical signature of rare and trace elements suggests derivation from melting under relatively low pressure condition (shallow depth). The results of U-Pb zircon dating of the studied are 97-100 Ma (mid-Cretaceous time). The initial 87Sr/Sr86 ratios and the initial εNd are 0.7049 and +4.54, respectively. [ABSTRACT FROM AUTHOR]

The Ghohroud granitoid body is located 116 km of north-west of Isfahan on the magmatic strip of Urumieh-Dokhtar belt. The body of granodiorite and tonalite with middle Miocene age intruded into the Jurassic shale and sandstones as well as the Cretaceous and Eocene limestone and marls in the north and the south of Ghohroud village caused the contact metamorphic of surrounding rocks lead to formation of skarns. On the basis of the petrographic and geochemical data the Ghohroud body is granodiorite and tonalite in nature and calc-alkaline and meta-aluminous composition which point to I-type granite forms in the tectonomagmatic environment related to continental arc. [ABSTRACT FROM AUTHOR]

The study area is located in the Southeast of Fariman and it is considered as a part of the central Iranian zone. According to field and petrographic studies the composition of volcanic rocks a range from basalt andesite-basalt andesite, trachyandesite to dacite with Paleocene-Eocene age. The dominant textures of the volcanic rocks are microlitic porphyric and glomeroporphyric and the major minerals are plagioclase, olivine, pyroxene, hornblende, alkali feldspar and quartz. Biotite, apatite, sphene and magnetite are as minor minerals. Microscopic studies reveal the presence of disequilibrium textures in plagioclases (eg. zoning and corrosion). The occurrence of xenolites indicates magma contamination. Based on geochemistry of major and minor elements, the studied rocks belong to calc-alkaline series with moderate to high potassium type and meta-aluminous nature. The geochemical behavior of major and trace elements reveals the normal trend of differentiation in the magma. According to geochemical data, garnet-lerzolite may be the principal source rock for the studied volcanic rocks which experienced 1 to 10% partial melting in a depth of around 90 to 100 km. Based on petrographic studies, some evidences of magmatic contamination can be distinguished which can be also supported by Nb and Ti negative anomalies and Pb positive anomaly on spider diagrams and Ce/Pb and Nb/U ratios. Enrichment in LILE and depletion of HFSE in the studied rocks as well as various petrologic diagrams point to magmatism in arc of an active continental margin. [ABSTRACT FROM AUTHOR]

The Eocene volcanic rocks of the Posht-e-Badam block represent very good exposures in Saghand (Khoshoumi Mountain), Alahabad and Chapedony areas (Yazd province). These rocks were developed during five volcanic phases: 1- Volcanic rocks of Alahabad area which are formed during three various phases: 1-1: The central andesitic phase ; 1- 2: The first andesitic fissure phase; and 1-3: The second andesibasaltic fissure phase. 2- The Chapedony andesite to andesibasaltics. 3- The Saghand (Khoshoumi Mountain) andesic rocks. On the base of field observations, the evidences of contamination are clearly noticed in the volcanic rocks of Saghand area which point to slower rate of magma ascending. The lowest volume of Eocene volcanic rocks exposed in Alahabad area. These rocks developed by two fissures and one central eruption. The presence of the highest volume of the Eocene volcanic rocks in Chapedony area displays active Chapedony fault during the Eocene time. The absence of contamination evidences in the rocks of Chapedony and Alahabad areas indicate the higher rate of magma ascending in compare to that of Saghand area. The occurrence of xenoliths and xenocrysts, the formation of fine grained clinopyroxenes around xenocrystic quartz, the sieved and anti- rapakivi textures, the gulf corrosion of quartz and the oscillatory zoning of plagioclases reveal magmatic contamination in Saghand area. The chemistry of clinopyroxenes and biotites display that these rocks, in nature, are similar to the calc-alkaline continental volcanic arc rocks. [ABSTRACT FROM AUTHOR]

Ghazan mafic-ultramafic intrusive is a small igneous body at the extremity of NW of Sanandaj-Sirjan zone in the NW of Iran, intruded into the early Paleozoic sedimentary rocks. This body includes non-mineralized mafic and mineralized ultramafic part (containing Fe-Ti oxides). The mafic rocks are composed mainly of pegmatite gabbro to micro gabbro, metagabbro and anorthosite, with a simple mineral assemblage (plagioclase, clinopyroxene, orthopyroxene, ilmenite). The ultramafic rocks include pyroxenite and wherlite (with high proportion of ilmenite and titanomagnetite) in accompany by large to small blocks of pure Fe-Ti oxide are widespread in the area . The ultramafic part is located within the intrusion and enclosed by mafic rocks. Based on the results of chemical analyses, the primary magma of mafic-ultramafic rocks, derived from a mantle source. During magma ascent the composition of magma has been changed from alkaline to sub-alkaline. U-Pb dating, of a primary and magmatic zircon, gives an age of 299 Ma and dating on metamorphic and inherited zircons shows maximum age of 541 Ma. The younger age represents the the Upper Paleozoic plutonism in the northern part of the Sanandaj-Sirjan zone. The older ages related to the Precambrian basement rocks or older basement rocks on the way of magma, which are incorporated in the magma as exnocryst. The greenschist facies metamorphism, high- temperature deformation as well as altered rocks are widely observed in the area. [ABSTRACT FROM AUTHOR]