Arash Syenite is located in central Iran and in Bafq metalogenic province, and has intruded into the Precambrian-Cambrian volcanic-sedimentary sequences. Size and distribution of minerals are not uniform in all parts of the body and vary from chilled margins to the central part of the pluton. Effects of tectonic movements, existence of uncommon textures in plagioclase crystals and the appearance of metasomatic textures are the main evidence for metasomatism. Study of elemental concentration deduced from mass balance calculation reveals the effects of alkaline metasomatism in Arash Syenite. Gain in K2O (and Rb) and Al2O3 with parallel losses in Fe2O3, CaO, Na2O, Ba and Sr are shown. Relative increase in Nb and Zr are due to leaching of mobile cations in this pluton.Decrease in Zr and Nb with parallel increase in SiO2, which is one of the most identical factors for the calc-alkaline differentiation, is remarkable in Arash Syenite. There is a clear change in Y, Th and Nb relative to Zr in this pluton and based on the constant ratio of Zr/Nb, the role of contamination and assimilation of country rock is insignificant in the pertrogenesis of this pluton. Negative anomaly for Nb and TiO2 suggest a subduction-related origin for the Arash Syenite.

The iron deposits in north of Semnan are located in the south of Central Alborz structural zone. Stratigraphically, the area consists of Paleozoic to Quaternary rock series exposures. The area has been affected by Semnan, Darjazin, Attari and Diktash faults. An intermediate to acidic granitoid body of calc-alkaline and metaluminous composition, representing I-type granite characteristics, has intruded the Eocene volcanopyroclastic rocks in the north of Semnan. Skarn development and iron mineralization have occurred at the contact of the intrusive body and the volcanopyroclastic rocks. Mineral Paragenesis consists of magnetite accompanied by hematite, oligist, pyrite, chalcopyrite, garnet, pyroxene and epidote. Geometry of the ore bodies is massive, lenticular and vein type and their texture is disseminated, brecciated, vein-veinlet and massive. Dominant alterations in the area are propylitic, argillic, silicic, sericitic, chloritic and pyritic, respectively. The intrusive body has many similarities with intrusive bodies which form Fe-skarn deposits. Variations in the calculated parameters for REE indicate contribution of magmatic origin hydrothermal fluids to mineralization and that the intrusive body has had the dominant role as source of the skarn ore materials. Along with the intrusion, emplacement and crystallization of intrusive body, Fe-bearing fluids have intruded the volcanopyroclastic rocks, forming sodic metasomatism and deposited iron ores in the north of Semnan which have many similarities with calcic Fe-skarn deposits.

At 60km north-east of Kerman city,near Sarashk village (Ravar, Kerman province) and along the Kuhbanan fault, several lamprophyric dikes have been intruded into Carboniferous to Cretaceous sedimentary formations. Petrographically these lamprophyres could be classified into two  groups: comptonites and sanaite. Olivine, clinopyroxene, plagioclase and potassium feldspar are the main minerals in all two groups. Mineral chemistry shows that olivines, clinopyroxenes and amphiboles are of chrysolite (Fo = 72.35-79.85)), augite (Wo = 44.3-50.2, En=  37.06-44.4, Fs = 9.24-14.6), and  kaersutite (Ca+Na = 2), (Na+K = 0.59-0.95), (Mg/(Mg+Fe2) = 0.63-0.76) composition, respecrively. Geobarometric and geothermometric estimations along with the tectonomagmatic diagrams for clinopyroxenes show that the parental magmas werealkaline in which the clinopyroxenes crystallized at pressure of 11-15 Kbar and temperature of 1150-1300 ◦C.Whole rock chemical analyses of these rocks show that the parental alkaline magma was originated from a metasomatized lithospheric garnet- spinel- lherzolite mantle source and emplaced in a post-collisional environment.

The Neian epithermal deposit in northwest of the Lut block is located in ~35 km southwest of Bejestan. The studies done on this deposit indicate the development of zonation in altered rocks around the ore-bearing siliceous veins and the existence of silicic (quartz, chalcedony, adularia, calcite, illite, and sericite), silicic-argillic (quartz, adularia, illite, sericite, and pyrite), argillic (illite, quartz, calcite, adularia, sericite, kaolinite, smectite, and chlorite), and propylitic (chlorite, calcite, albite, epidote, quartz, and smectite) alterations as the major alteration zones in this deposit that were formed during the five stages. Th geochemical diagrams, molar elemental ratios, and petrographic consideration illustrate the presence of transitional transformation and mineral conversion arrays during the development of hydrothermal system at Neian. Consideration of these diagrams indicate a wide spread of argillic and silicic and a relatively limited extent propylitic alteration zones in the Neian deposit. These diagrams also show that the mineral arrangements such as plagioclase-illite, plagioclase-adularia, illite-adularia, and plagioclase-smectite were developed during the prograde stages, whereas adularia-illite arrangement was formed during the retrograde (waning) stages of hydrothermal system. Permeability, high water/rock ratio in the host rocks (generated by faulting and the presence of extensive pyroclastic rocks) are the main factors for development of alteration zones and formation of widespread adularia in the area. In addition, considering the mineralogical composition of the deposit, the presence of minerals such as adularia and illite in the central and kaolinite in the peripheral part of the system may suggest that they were formed by the fluids having temperatures > 220 C and <140 C, respectively. The presence of mineral assemblage of quartz, adularia, illite, pyrite, chlorite, and calcite may reflect the involvement of upward flowing Chloride-bearing fluids with pH ranging from almost neutral to moderately alkaline. The contemporaneous formation of calcite, smectite, illite, and kaolinite in peripheral parts of the system was resulted by the reaction of CO2-rich fluids (containing hot vapors) with the host rocks. Increasing of temperature and potassium metasomatism in the central parts of the system caused widespread formation of illite at the first stage of alteration and of adularia-illite at the second (maximum K-metasomatism) during the geothermal activity at Neian. Concurrent with the waning stage of hydrothermal alteration and decreasing of K-metasomatism, illite replaced adularia again. The prevalence of conditions (for a long period of time) suitable for stability of illite may account for the greater abundance and extent of this mineral relative to adularia in the host rocks of Neian deposit.

Nepheline syenite intrusive of Kaleybar is located in South and West of the Kaleybar city in easternAzarbayjan province. This zoned intrusive complex is formed by penetration of two separated silica undersaturated and saturatated magmatic phases with Oligocene-Miocene ages. Undersaturated rocks are composed of alkali pyroxenite, mela alkali-gabbro to nepheline gabbro diorte, nepheline syenite and nepheline sodalite syenite dikes. Silica saturated rocks is consist of a quartz monzonitic stock, which has penetrated in the center of nepheline syenite intrusive and related quartz syenite - micro syenite dikes. Undersaturated phase has potassic alkaline affinity and nepheline syenites are miaskitic Malignite. In contrast, silica saturated rocks belong to high-K calc-alkaline to shoshonitic magma. Field observation, petrographical and geochemical studies, indicates that undersaturated rocks are comagmatic and crystal fractionation, accumulation and low density minerals floatation processes play significant role in their magmatic evolution. High enrichment of rare elements especially LREE and LILE compare to variable depletion of HREE and HFSE are infer a basanitic parental magma generated from a previously subduction-metasomatised lithospheric mantle source. Silica saturated magma of Kaleybar was probably resulted form the lower crust Partial melting and geochemical similarities resulted from partial melting of lower crust and its geochemical similarities with undersaturated parts is due to magma mixing and contamination. Repeatedly injection of alkaline and calc-alkaline magmas could be occurred in a post collision setting after Eocene in Azerbaijan region.

The Lakhshak granitoid pluton which is located at 10 km northwest of Zahedan, has intruded into the Eocene flysch sediments with an elliptical shape and NW-SE direction. This pluton after emplacement has been cut by numerous dykes with NE-SW trend. These dykes comprised about 20-30% of the Pluton with various compositions, ranging from granodiorite to monzodiorite in composition. The Lakhshak plutonic rocks are mainly metaluminous, calc-alkaline and belong to I type granites based on the P2O5 and Th content versus SiO2. Regarding TiO2 content these rocks resemble the continental margin granites. The MgO, Na2O, Ni, Cr content as well as Mg# and depletion in Y, these plutonic rocks are similar to the adakite, a rock type produced by partial melting of young oceanic crust. The low Ba/La content of the studied samples may suggest that subducted slab suffered dehydration prior to partial melting. These rocks are enriched in LIL, LREE, however, they are depleted in HREE and Y. In addition, they show negative anomalies of Nb, Ta, P and Ti, and positive anomaly of Pb. The negative anomalies of Nb and Ta may indicate the effect of mantle wedge metasomatism by oceanic crust. The positive anomaly of Pb may demonstrate continental crust assimilation by magma associated with mantle metasomatism. It seems that Lakshak pluton has been formed by subduction of Sistan young oceanic crust under the Afghan Block. Moreover, the low content of HREE and Y besides a decreased ratio of Yb versus SiO2, Y<15.13, Yb<1.2 and existence of amphibolite enxenoliths in these rocks may suggest partial melting of amphibolites. The latter is formed during the oceanic crust subduction in depth more than 35 km.

1-Introduction Corundum (Al2O3) is one of the rare metamorphic minerals that its formation requires particular chemical condition (low SiO2 and high Al2O3) in combination with high temperature (Simonet et al., 2008). Therefore, one of the most critical cases in the study of corundum-bearing rocks is the accurate determination of protolith and metamorphic conditions (Yakymchuk and Szilas, 2018). In the Broujerd area, Berthier et al. (1974) reported the corundum in migmatites for the first time. Despite the many studies in metamorphic rocks, these corundum-bearing rocks never reported in later works, until (Ghaffari, 2010) and then (Papi, 2015) again reported corundum-bearing rocks in the area and both concluded that they are a kind of migmatites, evidence of granulite facies metamorphism. Neither Berthier et al. (1974) nor Gaffari (2010) and Papi (2015) reported albitite rocks that are in direct relations with corundum-bearing rocks. Also differences between whole rock composition in migmatites and corundum-bearing rocks and its possible role in corundum formation, never discussed. 2-Materials and Methods Different samples collected for petrographic studies and finally, five samples had chosen for whole rock analysis (Table 1). Bulk rock compositions of selected samples were determined using an X-ray fluorescence spectrometer at the Zarazma Co., Tehran, Iran. Chemical compositions of minerals were obtained using a JEOL W-EPMA JXA8900-R electron microprobe in the Institute of Earth Sciences, Academia Sinica, Taiwan, at an acceleration voltage of 15 kV, a current of 15 nA, and a beam size of 2 nm. (Droop, 1987). The method used for Recalculation of Fe as Fe3+ and Fe2+. All mineral abbreviations are from (Whitney and Evans, 2010). 3-General geology and field relations Borujerd area located in Sanandaj-Sirjan Zone in the western part of Iran. Intrusive rocks, as main granitoids and rare norite, gabbro, and pegmatites, with NW – SE trend, injected along dominant schistosity in metapelites (Berthier et al., 1974), during middle Jurassic (175-170Ma; (Ahmadi-Khalaji et al., 2007; Mahmoudi et al., 2011). Contact metamorphism developed during magmatism, especially in the northern part of Broujerd batholith. Highest metamorphic grade restricted either to the northern part of granitoids or as large enclaves. Migmatites in Ab-Bakhshan area, show one of the most significant outcrops and located between granitoids and hornfelses. Based on Fig. 1, albitites dikes injected in migmatites. In general, towards albitites, migmatites first start to metasomatized and formed metasomatized-migmatites, then corundum-bearing rocks will appear either in contact or inside albitites. Migmatites are metatexite with the low-melt portion, generally with patchy structure. In petrographic studies, they include relatively uniform mineralogy: quartz, plagioclase and potassium feldspar are main minerals in the leucosomes with granoblastic texture, while biotite, cordierite, andalusite, sillimanites, spinel, and Fe-Ti oxides, are major minerals in mesosome, generally with lepidoblastic or grno-lepidoblastic texture. Their chemical composition (Table 1) with high Al2O3 and SiO2, and low alkali and calcium show that they have the pelitic origin. Metasomatized migmatites in the field are the same as migmatites, but under the microscope, andalusite and sillimanites start to replace by sericites, and biotites with chlorite. Near the corundum-bearing rocks (based on Figure 1) all andalusite and sillimanites completely replaced by sericites, all biotites with chlorites and also, feldspars altered. Comparing to migmatites, they have higher SiO2 and less Al2O3 (Table 1). Corundum-bearing rocks have different mineralogy. They mainly composed of corundum, chlorite, white mica (tin muscovites) and feldspar (albite), with rare rutile, ilmenite, and apatite. Albitites are mainly composed of albite (more than 80%) and quartz, sericites, potassium feldspars as minor minerals. Their chemical composition is entirely different from migmatites, with a low concentration of SiO2 and higher Al2O3 and MgO (Table 1). Albitites are deformed and make dikes and small patches in migmatites. They mainly composed of albite with rare muscovite, quartz, and k-feldspar. Their chemical composition is following high–Na plagioclases (Table 1. Figure 1. Schematic illustration of field relations between migmatites, corundum-bearing rocks and albitites (without scale) Table 1. Major elements analysis of selected samples, based on Figure 1 Sample BM-96.5 BM-96.8 BM-96.9 BM-96.102 BM-96.7 SiO2 63.85 71.08 43.25 43.73 61.45 Al2O3 17.35 14.65 28.38 26.55 19.54 TiO2 0.82 0.73 0.69 0.48 0.67 Fe2O3 7.49 3.6 4.57 6.94 2.02 MgO 2.2 1.95 8.7 8.68 2.75 MnO 0.16 0.05 0.05 0.07 CaO 0.64 0.8 0.54 0.92 0.51 K2O 3.35 2.39 5.48 2.79 0.32 Na2O 1.53 1.74 1.82 3.59 10.09 P2O5 0.22 0.1 0.06 0.09 0.16 LOI 2.31 2.91 6.46 6.09 2.48 4-Mineral chemistry Selected mineral analysis from corundum-bearing rocks is represented in Table 2. Corundum crystals in a mica matrix, have a relatively pure chemical composition (Table 2) and their aluminum content is above 1.99 a.p.f.u, only iron is a unique element that it reaches up to 0.006 a.p.f.u. Chlorite is one of the most abundant minerals in corundum-bearing rocks, which forms a large part of the rock's matrix. Chlorites usually contain rutile and or ilmenite inclusions. Chlorite are Mg-rich (Mg/Mg+Fe from 0.75 to 0.76; Table 2). In white micas, iron and magnesium are low and close to a pure muscovite composition. Feldspars are sodic in chemical composition, in which the XAb is 0.99 (Table 2). In other words, feldspars are pure albite. Cordierite is a rare mineral between feldspars and chlorites, and due to petrographic similarities, it is difficult to detect under the microscope. They are Mg-rich (Mg/(Mg+Fe)=0.81; Table 2). Rutile as inclusions in chlorite are relatively pure, and their iron and manganese are deficient (Table 2). Ilmenite is also found in some parts in the chlorite or the rock matrix, and its chemical composition is close to the ideal ilmenite, with little impurities (Table 2). Table 2. Chemical analysis of minerals in corundum-bearing rocks of Broujerd area. Only selected analyzes are provided Mineral Chl Chl Ms Ms Crn Crn Crd Crd Fsp Fsp Rt Ilm Point 1 2 1 2 1 2 1 2 1 2 SiO2 27.31 27.29 47.70 45.98 0.02 0.01 48.21 48.18 68.67 68.03 0.42 0.00 TiO2 0.05 0.06 0.09 0.00 0.01 0.05 0.00 0.00 0.00 0.00 98.78 53.97 Al2O3 21.50 22.51 34.86 37.72 99.82 99.71 33.04 33.12 19.42 19.41 0.25 0.00 Cr2O3 0.04 0.15 0.00 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Fe2O3 0.06 0.00 0.00 0.00 0.00 0.00 1.21 1.23 0.00 0.00 0.00 0.00 FeO 13.34 14.08 0.65 0.33 0.16 0.20 4.35 4.44 0.00 0.00 0.17 43.67 MnO 0.08 0.06 0.00 0.00 0.01 0.00 0.65 0.61 0.00 0.00 0.00 1.85 MgO 24.14 23.36 1.22 0.39 0.00 0.00 10.36 10.45 0.00 0.00 0.18 0.10 CaO 0.00 0.01 0.00 0.60 0.00 0.00 0.00 0.00 0.15 0.09 0.05 0.00 Na2O 0.04 0.00 0.61 1.04 0.00 0.00 0.00 0.00 11.23 11.58 0.00 0.00 K2O 0.00 0.00 9.76 9.22 0.00 0.00 0.00 0.00 0.05 0.04 0.00 0.00 Totals 86.56 87.52 94.89 95.28 100.08 99.97 97.82 98.03 99.52 99.15 99.85 99.59 Oxygens 14.00 14.00 11.00 11.00 3.00 3.00 18.00 18.00 8.00 8.00 2.00 3.00 Si 2.73 2.70 3.15 3.03 0.00 0.00 4.94 4.92 3.01 2.99 0.00 0.00 Ti 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.99 1.02 Al 2.53 2.63 2.72 2.93 2.00 2.00 3.99 3.99 1.00 1.01 0.00 0.00 Cr 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Fe3 0.01 0.00 0.00 0.00 0.00 0.00 0.09 0.10 0.00 0.00 0.00 0.00 Fe2 1.12 1.17 0.04 0.02 0.00 0.00 0.37 0.38 0.00 0.00 0.00 0.92 Mn 0.01 0.01 0.00 0.00 0.00 0.00 0.06 0.05 0.00 0.00 0.00 0.04 Mg 3.60 3.45 0.12 0.04 0.00 0.00 1.58 1.59 0.00 0.00 0.00 0.00 Ca 0.00 0.00 0.00 0.04 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 Na 0.01 0.00 0.08 0.13 0.00 0.00 0.00 0.00 0.95 0.99 0.00 0.00 K 0.00 0.00 0.82 0.78 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Sum 10.00 9.97 6.93 6.96 2.00 2.00 11.02 11.03 4.97 4.99 1.00 1.98 XMg 0.76 0.75 0.79 0.79 Mg/(Mg+Fe) 0.76 0.75 0.81 0.81 Or 0.31 0.20 Ab 98.96 99.40 An 0.73 0.40 5- Phase equilibria in the corundum-bearing rocks Phase equilibria for corundum-bearing rocks were modeled in the system Na2O-K2O- CaO-FeO-MgO-Al2O3-SiO2-H2O- TiO2 (Ti-NCKFMASH) using the THERIAK-DOMINO software v.03.01.12 (Capitani and Petrakakis, 2010) with the internally consistent thermodynamic dataset of (Holland and Powell, 1998). The activity models of (Baldwin et al., 2015) are used for feldspar, those of (White et al., 2002) for corundum, and (Coggon and Holland, 2002) for micas. The water content is taken from the 'loss of ignition' (LOI) during XRF analyses, following (Sarkar and Schenk, 2014), although the effects of variation in the amount of water calculated. The fluid phase is assumed to be pure H2O. The final calculated pseudo section is represented in Figure 2. Figure 2. Calculated pseudosection for corundum-bearing rocks in Broujerd area (Sampled BM-96.102 in Table 1 and Fig. 1). Gray region is following the mineralogy of corundum-bearing rocks. Dashed red and green lines represent equal values of Mg/Mg+Fe for chlorite and cordierite, respectively and their intersection show 605 °C - 3.3 kb as T and P, based on the mineral analysis in Table 2 6- Conclusion In the Ab-Bakhshan area, corundum-bearing rocks appeared as small patches, located in albitites or albitite-migmatite contact. Based on calculated pseudosection for migmatites, their composition is not suitable for corundum formation, even in high T. Using whole rock composition of corundum-bearing rocks, T and P estimated as 605 ℃ in 3.3 Kbar. Field relation between metasomatic rocks (albitites) and corundum-bearing rocks show that metasomatism was effective during corundum formation. The albitites occur most commonly in conjunction with other types of metasomatic rocks including scapolitised metagabbros and Mg-Al-rich lithologies such as orthoamphibole-cordierite schists (Engvik et al., 2014; Engvik et al., 2018). During Na metasomatism and albitite formation, Mg-Al rich fluids generated and cause chemical changes in migmatites, lead to appropriate whole rock composition for corundum formation. Na metasomatism could generate Mg-Al rich rocks, as corundum-bearing rocks of Broujerd area. So Mg-metasomatism and corundum formation either in migmatites or albitites, are consequences of Na-metasomatism in the area or are not evidence of very high T metamorphism. References Ahmadi-Khalaji, A., Esmaeily, D., Valizadeh, M., Rahimpour-Bonab, H., 2007. Petrology and geochemistry of the granitoid complex of Boroujerd, Sanandaj-Sirjan Zone, Western Iran. Journal of Asian Earth Sciences 29(5-6), 859-877. Baldwin, J.A., Powell, R., White, R.W., Štípská, P., 2015. Using calculated chemical potential relationships to account for replacement of kyanite by symplectite in high pressure granulites. Journal of Metamorphic Geology 33(3), 311-330. Berthier, F., Billiaul, H.P., Halbroronn, B., Marizot, P., 1974. Etude Stratigraphique, petrologique et structural de La region de Khorramabad (Zagros, Iran). These De 3e cycle, Grenoble. Capitani, C.d., Petrakakis, K., 2010. The computation of equilibrium assemblage diagrams with Theriak/Domino software. American Mineralogist 95(7), 1006-1016. Coggon, R., Holland, T., 2002. Mixing properties of phengitic micas and revised garnet‐phengite thermobarometers. Journal of Metamorphic Geology 20(7), 683-696. Droop, G.T.R., 1987. A General Equation for Estimating Fe3+ Concentrations in Ferromagnesian Silicates and Oxides from Microprobe Analyses, Using Stoichiometric Criteria 51, 431-435. Engvik, A.K., Taubald, H., Solli, A., Grenne, T., 2018. Dynamic Metasomatism: Stable Isotopes, Fluid Evolution, and Deformation of Albitite and Scapolite Metagabbro (Bamble Lithotectonic Domain, South Norway). Geofluids 1, 1- 22. Engvik, A.K., Ihlen, P.M., Austrheim, H., 2014. Characterisation of Na-metasomatism in the Sveconorwegian Bamble Sector of South Norway. Geoscience Frontiers 5(5), 659-672. Ghaffari, M., 2010. Petrology of metamorphic rocks in the southeast of Boroujerd. MSc thesis, Geological Survey of Iran, Tehran, Iran (in Persian). Holland, T., Powell, R., 1998. An internally consistent thermodynamic data set for phases of petrological interest. Journal of metamorphic Geology 16(3), 309-343. Mahmoudi, S., Corfu, F., Masoudi, F., Mehrabi, B., Mohajjel, M., 2011. U–Pb dating and emplacement history of granitoid plutons in the northern Sanandaj–Sirjan Zone, Iran. Journal of Asian Earth Sciences 41(3), 238-249. Papi, N., 2015. Petrogenesis of granulite facies rocks in the contact aureole of boroujerd complex. M.Sc Thesis, Kharazmi University (In persian). Sarkar, T., Schenk, V., 2014. Two-stage granulite formation in a Proterozoic magmatic arc (Ongole domain of the Eastern Ghats Belt, India): Part 1. Petrology and pressure–temperature evolution. Precambrian Research 255, 485-509. Simonet, C., Fritsch, E., Lasnier, B., 2008. A classification of gem corundum deposits aimed towards gem exploration. Ore Geology Reviews 34(1), 127-133. White, R.W., Powell, R., Clarke, G.L., 2002. The interpretation of reaction textures in Fe-rich metapelitic granulites of the Musgrave Block, central Australia: constraints from mineral equilibria calculations in the system K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3. Journal of Metamorphic Geology, 20(1), 41-55. Whitney, D.L., Evans, B.W., 2010. Abbreviations for names of rock-forming minerals. American mineralogist 95(1), 185. Yakymchuk, C., Szilas, K., 2018. Corundum formation by metasomatic reactions in Archean metapelite, SW Greenland: Exploration vectors for ruby deposits within high-grade greenstone belts. Geoscience Frontiers 9(3), 727-749.

The study area,~12 km to the southwest of the city Behabad, is a part of the Posht-e-Badam Block in Central Iran. Igneous rocks in the area occur as intrusive, sub-volcanic and volcanic bodies and exhibit a wide range of composition felsic to mafic. The intrusive and sub- volcanic rocks include the relatively large Homijan granitoid, Ferdows granitoid, gabbro- diorite stocks and Kuh-Siah sub- volcanic rhyolitic dome. The Homijan granitoid is composed of a shallow-level intrusion in the center to rhyolitic lavas and tuffs in the margins. The whole assemblage is covered by dolomites of the Rizu series, with no thermal metamorphism in the covering rocks. Homijan granitoid displays porphyritic, porphyroid and graphic textures composed of coarse plagioclase, alkali feldspar and quartz in a fine- grained quartz- feldspatic matrix; the marginal rhyolitic lavas have porphyritic and spherolitic textures with quartz and alkali feldspar phenocrysts. Rhyolitic tuffs have porphyroclastic texture. Ferdows granite has hetero-granular, graphic and perthitic texture composed of quartz, orthoclase and plagioclase. Kuh-Siah rhyolites have porphyric, felsophyry and felsitic textures with small quartz and alkali feldspar phenocrysts. Geochemical studies demonstrate that Homijan and Ferdows granitiods and the marginal rhyolites of the Homijan, as well as the Kuh-Siah rhyolitic dome have high- K calc- alkaline to shoshonitic nature and can be classified as S-type peraluminous granitoids with some tendency to I-type granitoids. Based on the spider diagrams, all rocks have similar trend which is indicative for their genetic relation. These diagrams indicate enriched LILEs (Rb, K, Th and Pb) along with negative anomalies of HFSEs (Nb and Ti). Chondrite normalized REE patterns demonstrate LREEs-enriched patterns with high ratios of LREE/HREE.The positive and negative anomalies of the mentioned elements in the studied rocks probably are related to lower partial melting degrees of a metasomatized mantle along with crustal contamination of the magma. Based on field investigation, petrographic studies and geochemistry, and using the granitoid discrimination tectonic setting diagrams, it seems that Homijan granitiods and related felsic rocks formed in a post- collisional setting within the Posht-e-Badam Block.

Khankandi pluton is located in northwestren part of Iran, within Garadagh (Arasbaran) - south Armenia block. Main units of the pluton are monzonite and granodiorite associated with minor gabbro and lamprophyric and dacitic dykes. Granodioritic plutonism is followed by gabbro and monzonite. Lamprophyric and dacitic dykes are emplaced at the end of the granodioritic plutonism. Gabbro and monzonites are shoshonitic, and granodiorites and dacites have high K-calc alkaline nature and charactistics of C-type (potassic or continental) adakites and high Ba-Sr granitoides. Lamprophyres are alkaline and have camptonitic composition. The monzonites follow fractionation trend of gabbro with minor crustal assimilation and contamination. Melting of garnet bearing mafic lower crust, metasomatised lithospheric mantle and upwelling asthenosphere produced granodioritic and dacitic, shoshonitic gabbro and lamprophyric magma respectively. The production of various magma types in the Oligocene of the Arasbaran occurred in response to slab break off and/or delamination of lithospheric mantle and upwelling of asthenosphere. Plutonism occurred after collision between Iranian and Arabian plates and crustal thickening in the extensional post collisional tectonic setting.