جستجوی مقالات مرتبط با کلیدواژه "کالک‏ آلکالن" در نشریات گروه "زمین شناسی"

Mineral chemistry has a significant role in determining the stages of magma evolution. Amphiboles, Biotite, plagioclase, and chlorite are minerals whose chemical composition show the temperature and pressure conditions of magma. These minerals are often used for the petrogenesis of granitoid bodies and record the characteristics and geochemical features as well as tectonic conditions of the producing magma (Abdel-Rahman, 1994; Nachit et al., 2005). The granitoid bodies of west Yazd have wide outcrops with different compositions. These rocks are part of the volcano-plutonic belt of Central Iran (Aftabi and Atapour, 2000) with calc-alkaline nature, meta luminous, and mostly of I-type (Hassanzade et al., 2002). The Hamaneh monzogranite bodies, with light color and dark enclaves, are located in 45 km at E53°48ˊ to E53°58ˊ longitude and N31°50ˊ to N31°56ˊ latitude. This area is part of the Shirkuh Mountain in Yazd with a northeast-southwest trend. Hamaneh monzogranite belongs to the Oligocene magmatic activity. In the present research, the mineral chemistry of amphibole, biotite, plagioclase, and chlorite has been investigated to determine the origin and stages of formation and evolution of the magma.

Regional Geology:

The studied area geologically located in the middle part of the Urmia-Dokhtar magmatic zonewith a wide collection of Cenozoic magmatic rocks and is characterized by a length of about 2000 km, and a width of approximately 50 to 150 km, parallel to the metamorphosed zones of Sanandaj-Sirjan and Zagros, has a wide collection of Cenozoic magmatic rocks. This area has witnessed extensive magmatic activity in the Cenozoic, especially in the Eocene, which during the Oligocene-Miocene hosted numerous intrusive masses with different ages and compositions (Hassanzadeh et al., 2002). The oldest formation in the region is the green siltstone shale and sandstone of the Kahar Formation. The dolomitic rocks of the Soltanieh Formation are unconformably on the Kaher Formation with purple and cream-colored sand shale layers. The Permian sediments (Jamal Formation) composed of limestone and dolomite layers and the Mesozoic sediments started with a dark unit of volcanic laterite rocks with the Lower Triassic followed by dolomitic rocks belonging to the Otri Formation. The shale and sandstone of the Shemshak Formation are upper Triassic sediments. Cretaceous sediments are exposed in the form of destructive rocks. Upper Triassic (Sangestan Formation) has a variety of conglomerate and conglomerate sandstones with round to semi-round pieces of sandstone and Shirkuh granite. The Paleogene begins with the Kerman Formation conglomerate. Then, there are alluvial cones, alluvial plains, and alluviums of young rivers.

For the lithology and chemistry of minerals in Hamaneh monzogranite, 20 thin-section samples were selected for chemical analysis of amphibole, plagioclase, biotite, and chlorite minerals and sent to Oklahoma City University laboratory. Microprobe analyses were performed with the Cameca model SX100 device with an accelerating voltage of 15 KV and current intensity of 15 nA. The results of chemical data of amphibole, biotite, feldspar, and chlorite minerals are given in Tables 1 to 4.Petrography and Minerals Chemistry.It is often fine to medium grain texture, granophyric and perthitic texture. The main minerals are orthoclase, plagioclase, and quartz. Orthoclase with an abundance of 25 to 32% is amorphous to semi-amorphous, and plagioclase is a frequency of 24 to 44% that was often as shaped to semi-shaped with zoning. The quartzes are often amorphous and intergranular, and some have wave extinction and fractures with a frequency of 19 to 31. The minor minerals were amphibole, biotite, sphene, zircon, and opaque minerals. Amphibole is green with an abundance of 2.5 to 4.5%, shaped to semi-shaped with a simple twinning. Biotite crystals with an abundance of 2 to 4%. Mineral chemistry of amphiboles was shown as calcic magmatic amphiboles, ranging from magneiso-hornblende and actinolite. Which formed at 530-890℃ and up to 4.3 kbars. That was shown depth 3 to 5.40 km and fO2 (0.5). <Fe#, which corresponds to the calc-alkaline nature in a subduction environment (Anderson, 1996; Rieder et al., 1998). The Hamaneh amphiboles were formed in active continental margins related to subduction. Mineral chemistry of biotites point to a primary biotites that are magmatic and emplaced between annite and phlogopite in the Mg-biotite range. The Hamaneh biotites are I-type indicating the tectonic setting of the calc-alkaline granitoid magmatic series in the subduction zone. Biotites under study were formed at 650-730°C and a pressure of 10-11 to 10-14 kbar. Also, feldspar are (An21 to An32) (Or45 to Or59) orthoclase. The feldspars are of the oligoclase-andesine type, as well as in the feldspar thermometry diagram (Elkins and Grove, 1990; Deer et al., 1991) that was formed in 700 to 800ºC. Based on mineral chemistry, the chlorites are ripidolite and pycnochlorite in composition. Regarding the relatively high iron amount, they have formed at 330 and 360 ºC by alteration of biotite and amphiboles.

The Hamaneh monzogranite, with the main minerals of quartz, orthoclase, plagioclase, amphibole, biotite and secondary minerals of sphene, zircon, and apatite lies in the west of Yazd. The main textures are medium-fine-grained, granophyric, and myrmekite. This body is calc-alkaline and type I. Based on mineral chemistry data, the crystallization of minerals was according to the Bowen series. The calcic amphiboles of magnesio-hornblende to actinolite nature crystallized at 890-530 ℃.Simultaneously with this mineral, oligoclase-type plagioclase to andesine crystallized at 700-800 ℃ and magnesium biotites at 730-650 ℃. Finally, due to secondary alteration, chlorite was formed from the biotite and amphibole developed at a temperature of 330 to 360 ℃ All these minerals point to the mantle nature of the parent magma produced these mineral and have suffered crustal contamination during the ascent. This magma originated at a depth of 3 to 5.5 kilometers, pressure of 0.5 to 4.5 kbars, temperature of 530 to 890 ℃ and at oxidizing conditions. The parent magma of the rocks under study belongs to the subduction structural ground position related to the active continental margin.

The study area, Tarom, is situated in northwestern Iran, within the Zanjan province. Geologically, it falls within the western Alborz zone, a volcanic-plutonic belt, oriented northwest-southeast. This region, extending from Qazvin (west of Taleghan) to the north-northwest of Miane and north of the Manjil embayment, is bounded by the Abhar-Zanjan-Miane axis to the south (Ghorbani, 2009). Within this mountain range, numerous intrusive masses, primarily granodiorite, have intruded into the Eocene volcanic rocks. These masses, including the Bakhtar Takhestan, Khorasanlu, Zaker, and Chal masses, follow a northwest-southeast trend, aligning with the overall orientation of the Tarom mountains. They are arranged in two parallel rows, cutting through the older volcanic formations.

Geology of the area:

The most important rock units in the Tarom Mountains consist of Eocene pyroclastic rocks, including andesite, rhyolite, basalt, andesite basalt, and rhyodacite, as well as shear tuff and andesite tuff. The region's main elevations are composed of Eocene volcanic and volcano-clastic rocks, along with Oligocene intrusive masses, which form the bulk of the mountain unit. Oligocene trachytic deposits, which are deposited on the Eocene units at an angle of approximately 23 degrees, are exposed in the northern part of the Kabbarik syenitic porphyroid stock. The syenitic porphyroid stock has intruded into the Eocene volcanic and volcano-clastic rocks.This study is grounded in field surveys, sampling of the slightly intrusive mass, and the examination of thin sections. Additionally, chemical analyses were conducted on ten samples from Zarazma Company to determine major, minor, and trace elements using inductively coupled plasma mass spectrometry (ICP-MS). Two samples were also analyzed using electron microscopy. To analyze the mineral composition of Kabbarik rocks for major elements, a JEOL JXA-8100 Superprobe electron microprobe (EMP) equipped with an Oxford Instruments INCA EDS system was employed at the Institute of Geology and Geophysics, Chinese Academy of Science. A 5-micron spot size, a 20 nA beam current, and a 15 keV accelerating voltage were utilized during these analyses.

Petrography:

The intrusive Kabbarik stock exhibits a porphyritic texture, characterized by euhedral to subhedral phenocrysts of alkali feldspar. Its primary mineral composition includes alkali feldspar (Orthoclase) constituting 65-70 Vol.%, followed by 10-15 Vol.% clinopyroxene (diopside), 5-7 Vol.% anorthoclase, and 3-5 Vol.% secondary minerals such as olivine, altered to iddingsite. Minor amounts of apatite, zircon, and dark minerals are also present. Orthoclase phenocrysts often display Carlsbad and polysynthetic twinning. Megacrysts of Orthoclase may contain tiny inclusions of olivine and clinopyroxene, exhibiting a poikilitic texture. Some crystals exhibit a sieve texture, and in certain cases, overgrowth on plagioclase results in a Rapakivi texture. Clinopyroxene (diopside) crystals are generally euhedral to subhedral, with some containing small dark mineral inclusions distributed along their edges and conforming to their shape. Subhedral crystals of iddingsitized olivine are scattered throughout the rock matrix in small quantities. The overall texture of the microlithic rock remains porphyritic.

Mineral Chemistry:

The chemical composition of clinopyroxene and alkali feldspar minerals from the syenitic stock was analyzed using a JEOL JXA-8200 electron microscope at the Department of Geology and Geophysics, Chinese Academy of Sciences.Based on relevant diagrams, the clinopyroxenes were classified as diopside-type (Eby et al., 1998; Morimoto, 1988). The chemical composition of the pyroxenes indicates a sub-alkaline, volcanic arc magmatic setting. EPMA analysis of the alkali feldspars revealed an anorthoclase composition (Deer et al., 1991).

Whole Rock Geochemistry:

The chemical analysis of significant, rare, and rare earth elements (ICP-MS) reveals a calc-alkaline composition for the intrusive mass of the syenite zone and its parent magma. Normalized spider diagrams compared to chondrite demonstrate a clear enrichment of light rare earth elements (LREE) and incompatible elements relative to heavy rare earth elements (HREE) in the examined rocks. Based on tectonic environment diagrams, the studied samples are classified as post-collisional.

The predominant rock formations in the Tarom Mountains consist of Eocene volcanic and volcaniclastic rocks, which constitute the bulk of the mountain range. The investigated syenitic stock, intruding into the overlying rocks, dates back to the Oligocene epoch. Based on spider diagrams, the absence of significant heavy rare earth element (HREE) depletion suggests a mantle that has been metasomatized by subduction-related fluids. Studies indicate that the analyzed samples originated in a setting associated with an arc and a post-collisional environment.

Middle Miocene igneous rocks are located in the Northeast of Joveinan, the middle part of the Urumieh-Dokhtar Magmatic Belt. The igneous rocks have intruded into the Eocene volcano-sedimentary units. The rocks consist of diorite, quartzdiorite, and monzodiorite. They contain plagioclase, hornblende, biotite, pyroxene, orthoclase, quartz, and opaque minerals, and have granular to porphyroid textures. Field and petrographic evidence such as a lack of thermal metamorphism and graphic texture suggests that the rocks crystallized at a shallow depth. The rocks exhibit characteristics of I-type granitoids and a calc-alkaline nature with metaluminous affinities. The enrichment of large ion lithophile elements (LILEs) and the negative anomaly of Ta, Nb, and Ti elements in the primary mantle normalized diagram demonstrate subduction-related magmatism in the continental arc setting. The chondrite normalized pattern of the rocks (Lan/Ybn= 3.68-5.64) suggests a low degree of partial melting and the absence of garnet as a permanent phase in the source region. Based on the petrological data, the parental magma has been produced in the subduction setting of the collisional zone. The primary magma resulting from the partial melting of the subducted lithospheric mantle intruded into the continental crust. The magma underwent numerous changes and evolution during ascent and created the intrusive rocks of Northeast Joveinan.

The Marphioon pluton in the southwest of Neyasar city and central part of Urmia-Dokhtar magmatic arc is among the Neotethyan oceanic lithosphere subduction-related intrusions. We used field evidences, petrography, geochemistry and U-Pb geochronological and aeromagnetic data to suggest a tectonomagmatic scenario for the intrusion. The composition of this circular pluton that has intruded into the Eocene volcano-sedimentary units changes from intermediate rocks to more tonalitic ones. The Marphioon granitoid gives rise to contact aureole zone with different peripheral thicknesses. U-Pb geochronology of a sample from southern part of the pluton suggests that these rocks have crystallized at 18.89±0.20 Ma in Early Miocene (Burdigalian). The rocks belong to medium-K calc-alkaline series and are metaluminous with I-type affinities. In terms of geodynamic setting, this intrusion is classified as volcanic arc granites and active continental margin granites. Qualitative interpretation of aeromagnetic data suggested a dioritic to gabbroic composition due to high magnetic susceptibility. The Marphioon intrusion is strongly tectonized due to faulting. Basement dextral strike-slip faults and their sinistral conjugates are potential mechanisms for its exposure. The pluton appears as two or three segmented bodies due to the presence of minor faults. Based on the aeromagnetic data this intrusion has a dip towards the northeast. It seems that the Marphioon magma in an active continental margin, originated from the partial melting of the lower continental crust with the involvement of mantle-derived melts, where mafic magma in mantle wedge has provided optimal temperature and fluids for this melting in the lower crust. Collectively, the Marphioon intrusion seems to be emplaced during the transition time from subduction to collision in the Urmia-Dokhtar magmatic arc contemporaneous with the closure of the Neotethyan Ocean.

In the northwestern part of the Sanandaj-Sirjan zone, mafic intrusive bodies are aligned with the trend of the Zagros orogenic belt. In this part of the Iranian lithosphere, magmatic activity occurred during three main periods: Cretaceous, Eocene, and Miocene-Quaternary. In the first of two stages, the magmatic activity was associated with subduction-related magmatism at the active continental margin, whereas the last phase was characterized by calc-alkaline magmatism related to post-collision regime. The intrusive mafic bodies of Qobadlo, Chupankareh, and Qaraqoshun at the southern margin of Lake Urmia in the northern part of the Sanandaj-Sirjan zone intruded within the complex of Cretaceous shale, shale-sandstone, and siltstone. U-Pb dating on zircon performed on these bodies indicates an age of 99 Ma. The SiO2 content of these bodies ranges from 46.17 to 53.35%, Al2O3 13.1 to 18.49 % Fe2O3 3.11 to 5.8%, and their TiO2 content ranges from 1.9 to 4.0%. Positive anomalies of large ion lithophile elements and LREE compared with negative anomalies of elements such as Nb, P, Zr, and Ta (HFSE), the La/Nb, Ba/Nb ratios, and the REE pattern show a good correlation with the magmatic rocks of subduction zones.

The study area is located in the SaSZ, NE of Songhor city, Kermanshah Province. Based on field observations and mineralogical data, the Azizabad-Hazarkhani I-type calc-alkaline granitoid consists of granites, monzonites and diorites with small volumes of gabbroic rocks. Co-variations in major and trace elemental abundances do not indicate a continuous compositional suite and therefore do not suggest a co-magmatic origin. According to geochemical evidence, the samples are enriched in incompatible elements such as Th, Rb, La, Ce and Nd and depleted in Nb, Ti and Eu, with metaluminous affinity. These characteristics reflect the role of continental crust and crust-derived melts. Tectonic setting discrimination diagrams suggest that this complex belongs to the volcanic arc and is related to an active continental margin setting. According to the geological history of this area, it can be attributed to the subduction of Neo-Tethyan oceanic crust below the Central Iran microplate. We suggest that the Parishan and Darvazeh mantle-derived basaltic magmas may have provided the heat required for the partial melting of various source rocks, including amphibolites, meta-basites, and meta-andesites, through diffusive heating.

The Chahargonbad batholite is located  close to Sirjan and southeast of Urumieh-Dokhtar magmatic zone. The batholite's composition is acidic to intermediate that is intruded into the Eocene volcanic rocks. Although the main volume of these rocks consisted of granodiorite and monzogranite, this mass contains numerous mafic microgranular enclaves with a combination of diorite and monzodiorite. Also, microgranular dykes have cut the mafic mass.  Existence of field evidence such as mafic microgranular enclaves with spherical to oval shapes, bell and rod shaped mafic microgranular enclaves, the presence of synplutonic mafic dykes, as well as textural disequilibrium evidences indicate the absence of plagioclase with oscillatory zoning and repeated analytical levels, and Osley quartz in the presence of enclaves. As they grow, they are minerals and evidence for magmatic mixing. Enclaves show higher values than the host rock in most of the basic elements, such as Al2O3, CaO, MgO, Fe2O3, TiO2, P2O5. The elements (REE), host granite rocks and associated enclaves show relatively differentiated REE patterns with sloping LREE patterns and flat MREE and HREE patterns. Based on the tectonomagmatic environment determination diagrams, all samples from the Chahargonbad (studied area) are located in the arc island setting due to subduction and show the characteristic of active continental margin setting.

Zardkooh is located in Western Alborz zone in the structural divisions of Iran. According to many published researches, most of the magmatic activities in the north and northwest of Iran are related to the Neotethys orogeny process, which are the result of the subduction of the Neotethys crust, the collision of the Arabian plate with Iran, and the tectonic regimes that occurred following the collision. For the purpose of the present study, the nature, the genesis and the tectonic setting of intermediate intrusive rocks were determined using whole rock and mineral chemistry. Incidentally, Microprobe analyses results were used to document the precise chemical composition of the rocks studied and the formation conditions of the minerals as well.

Geology of the area:

The exposed rock units in the studied area mostly include the Eocene (lava and pyroclastic rocks belonging to the Karaj Formation), but locally the Paleocene (the detrital sedimentary rocks of Fajan Formation), the Permian (the detrital sediments of Dorood and the limestones of Ruteh Formations) and the Carboniferous (the limestone of Mobarak Formation) outcrops and the Oligo-Miocene intrusive bodies are also present. Most of the intrusive masses are composed of gabbroic rocks, but some of them also have intermediate compositions, which are the goal of this research. These rocks are mostly seen as dykes and relatively small stocks.

In order to investigate the geochemical properties, five samples were sent to Zarazma company in Iran for whole rock chemical analysis. In the laboratory of Zarazma company, the amounts of oxides of the major elements were determined using the ICP-OES method. The abundance of rare earth elements and refractory elements were measured by ICP-MS method. A monzonite sample with freshest minerals was analyzed by EPMA at the Iran Mineral Processing Research Center in Karaj (I M P R C), in order to understand the chemical compositions of minerals and their application in petrogenesis.

Petrography:

According to petrographic studies, the intermediate intrusive bodies exposed in the study area are mostly microdiorite, monzonite and monzodiorite. The textures of monzonites are porphyroid and their minerals are zoned. The principal minerals are plagioclase (An17-An45) and orthoclase, and the minor minerals are mostly biotite (phlogopite to magnesium-rich biotite), amphibole (ferropargasitic hornblende to pargasitic hornblende), clinopyroxene (augite and salite) as well as opaque minerals set in a groundmass consisting of kaolinized orthoclase, some quartz and opaque minerals as well. Microdiorite has porphyroid texture and the phenocrystals include kaolinized plagioclase, biotite, hornblende and opaque minerals, and the groundmass is composed of altered plagioclase, few quartz and opaque minerals. The textures of monzodiorite are various in different samples, so that in some it is medium granular and in others is intergranular. All the samples are characterized by the presence of the abundant plagioclase (An31) and orthoclase, clinopyroxene, biotite, opaque minerals and a small amount of quartz, apatite and zircon are also occurred in some samples.

Mineral Chemistry:

The chemical compositions of biotites and clinopyroxenes indicate that the magmatic series of intrusive igneous rocks of the studied area is sub-alkaline and calc-alkaline type.Based on the composition of clinopyroxenes, the tectonomagmatic environment of the magma formation of the investigated rocks is volcanic arc and active continental margin type. Based on the microprobe data obtained from the biotites, the studied granitoids are classified as the ilmenite series and were derived from the mantle material or a mixture of mantle –crust.

Whole Rock Geochemistry:

The high potassium calc-alkaline and shoshonitic nature of the rocks under study are displayed by magmatic series determination diagrams, Moreover, the REE similar pattern point to their common origin. The strong negative anomaly of Nb, Ta, and Ti elements in the spider diagrams are of the prominent characteristics of subduction-related continental arc magmas. The positive anomaly of Pb, K and in general the enrichment of LILE elements are also attributed to crustal contamination of magmas. The geochemical data on the tectonomagmatic discrimination diagrams are placed in the realm of volcanic arc environment located on the continental crust. Their parent magma has a compositional similarity with melts derived from an enriched mantle, and according to various diagrams, it was derived from about 10-20% melting of a garnet-spinel peridotite source enriched by mantle metasomatism as a result of the addition of products derived from the subducting slab at depths of 100 to 110 km.

The geochemical data in combination with mineralogical study indicate that the investigated rocks belong to a subduction environment and were originated from an enriched source, but due to the great distance between the Cenozoic magmatic belt of Alborz and Urmia Dokhtar magmatic arc (and the subduction site of the Neotethys oceanic crust) a back-arc basin can be considered for the region, which was in the early stages of evolution but was completely affected by the characteristics of the arc magmas (Teimouri, 2011; Asiabanha and Foden, 2012). Like magmatic arcs, the formation of magma in these environments was also caused by the inflow of fluids resulting from the dewatering of the subducting oceanic slab and the melting of the metasomatized mantle wedge on it. During magma ascent through the continental lithosphere, the magma suffered contamination and some of its chemical properties have been dictated to the magma.

Numerous intrusive rocks of various sizes, dominated by granodiorite-granite, intrude the Sanandaj-Sirjan Zone (SSZ) (Torkian et al., 2008; Mollaei Yeganeh, 2018). They are S-I-and A-types in composition and ideal for studying the linkage between tectonic settings and the magmatic evolution of igneous rocks. Diverse scenarios have been proposed to explain the origin of A- type granitoids: (i) extreme fractional crystallization of parental mafic magmas derived from the mantle (with/ without crustal contaminations, (ii) high temperature partial melting of crustal granitic rocks (iii) partial melting of granulites OR charnockite, (iv) a metasomatic origin (Eby, 1992). These Atype granites are generally thought to have formed in an extensional setting, but their source regions and tectonic attributes are still a topic of debate. The present paper describes the field relationships, petrography and whole-rock geochemistry of A-type granitoid; these data are then used for the interpretation of the magma sources, tectonic setting and magma-generation processes for A2-type granitoid in NE-Sonqor.

The volcanic complex of North Khour  located in southern Khorasan province, 90 km northwest of Birjand in the Eastern of  Iran. The rocks under study are basaltic andesite, andesite and trachyandesite, latite, dacite to rhyodacite with tuff and breccia as pyroclastic rocks. The volcanic rocks are predominantly calc-alkaline nature with some tholeiitic affinity and porphyry texture. Iron mineralization developed as magnetite, hematite and small amount of goethite with magmatic origin, on the base of field observations. Bornite as the only and the primary Cu ore occurred as a small body. The presence of minor amounts of bornite and pyrite as the sulfide phases as well as the absence of the other Cu primary sulfide ores in the area along with secondary Cu mineralization phases reflect a hydrothermal solution with high oxidation degree which has passed the latest magmatic differentiation and gave rise to form surface Cu ores as chalcocite in supergene zone. The thermobarometry of fluid inclusions studies from Ghar Kaftar and Hoze Sabz, yield temperature range of 178 -324 C for Cu mineralization. Therefore, it seems that Cu mineralization is related to epithermal to mesothermal conditions.

The magmatic complex of Azadegan, composed of basalt, andesitic basalt, andesite, gabbro and diorite, located 45 km northwest of Shahrekord and in the middle part of the Sanandaj-Sirjan zone.. The study rocks are dominated by plagioclase, olivine, pyroxene, hornblende as well as biotite and calcite as minor minerals. Geochemically, the rocks under study are calc-alkaline in nature and are characterized by Ce, Zr, Ba, and Sr depletion. Chondorite- normalized REE pattern illustrates LREE enrichment relative to HREE. Geochemical data of the studied samples indicate partial melting of the mantle source with the influence of fluids and sediments of the subducted crust during subduction. The ratio of Th/Yb (2-2.75) values are in consistent with those of the mature arc islands magma. Also, Ce /Y and Sr/Y ratios indicate the thickening of arc islands along with orogenic processes and maturation of arc islands in the study area. The for mentioned ratios also represent the thickness of crust up to 50 km., during orogenic processes at the end of subduction stages of the Neotethys.

Zardkuh igneous complex is located in 35 km Southeast of Iranshahr and is geologically situated flysh zone and the Sistan-suture zone. Rock units in the area are Ophilitic rocks (upper Cretaceous), Eocene flysh and Oligomiocene intrusive and extrusive rocks (Zardkuh igneous complex). Patterns of minor and rare earth elements normalized to Primitive mantle and Chonderit show low enrichment to LREE such as La, Ce and Sm than to HREE such as Ho, Yb, Tb and Lu. The dip of digram is soft to HREE and in the extrusive rocks is low increased. . it is thought that the constituent magma of these rocks from the mantle wedge above the subduction plate, which is usually affected by the fluids released from the subducted plate and its elements (including Silica, potassium and sodium) can produce such magma. So these rocks are related to magmatism and subduction Neo-Tehyan oceanic between Lut and Sistan blocks.

The volcanic rocks of Bayram Abad area, located 12 km northwest of Neyshabour, are dominated by the Paleogene units composing of dacite and andesite rocks. The essential minerals of the rocks under study are plagioclase and amphibole with predominant textures including porphyry, sieve, trachytic and glomeroporphyritic. Composionally, they are acidic to intermediate and calc-alkaline affinity. The absence of negative Eu anomaly, low HREE values (i.e. Yb=0.92-1.11 ppm, Y=8.7-11.4 ppm), high Sr values (293-1029 ppm), high Sr/Y (29.08-90.26), high SiO2 content (59.96-65.89 wt%) and low K2O/Na2O (0.27-1.13) are remarkable geochemical criteria of the rocks studied. Moreover, Both Chondrite-normalized rare earth element (REE) patterns enriched in LREE with respect to HREE and normalized to primitive mantle spider diagram indicate that these rocks are adakitic in nature belonging to group of silica-rich adakites (HSA) The negative anomalies in HFSE (i.e. Nb, P, Ti) and high La/Yb (over 12) point to the characteristics of magmas associated with the continental active margin. It is possible that the parent magma generated by the melting of the eclogite or amohibolite garnet rocks resulting from the metamorphism of the Sabzevar Neotethys subducted oceanic slab underneath the southern edge of the eastern Alborz zone during the Miocene.

The Meshkin-Rasht Abad area is a small part of the western Alborz-Azarbaijan magmatic belt (AAMB). Field investigations reveal that andesitic-basalt rocks are the dominant rock units of the area with high-K calc-alkaline to shoshonitic affinities. On the basis of geochemical features all rocks are enriched in light rare earth elements (LREE), large ion lithophile elements (LILE) and have positive anomalies of Pb, U and Cs and Ti, Sr and Nb negative anomalies. These volcanic rocks have the criteria of active continental margin arcs on tectonomagmatic discrimination diagrams. Geochemical data, including low amounts of Cr, Ni, V, and Zr/Nb ratio suggest the enriched mantle source (lithospheric mantle) for the rocks under study. Moreover, the diagrams of the ratio of highly incompatible elements indicate the effect of slab-derived fluids on the magma generation. The Ce/Pb low value as well as various geochemical diagrams demonstrate that the magma is possibly contaminated by continental derived-crustal materials.

Bazman volcano is located in the Makran-Chaghi magmatic arc in southeastern Iran. Many studies have been done on this volcano, especially of petrology such as: Biabangard and Mollazadehbarvati, 2017; Berberian and Berberian, 1982; Mohammadi, 2005; Sahandi et al., 2010; Schmidt and Dabiri, 2019; Firoozkoohi, et al., 2017; Ghodsi et al., 2006; Glamghash et al., 2015; Karimpour et al., 2012; Stocklin, 1977; Richards et al., 2012. In this article we study the origin and tectonomagmatic environment of Bazman volcano with by geochemical data of whole rock and mineral chemistry.

We were selected 150 samples from of Bazman volcano. Then prepared 100 thin section and selected 15 samples with the least alteration for analyses. Samples were analyzed by XRF and ICP-MS methods at Yamagatai University in Japan. In order to study the chemistry of minerals in Bazman volcanic rocks, 18 points of plagioclase minerals, 12 points of pyroxene minerals and 7 points of hornblende minerals were analyzed by electron microprobe.

Bazman volcano is composed of andesite, basalte, dacite and rhyodacite lavas and similar pyroclastic flows. These rocks have mainly plagioclase, pyroxene, olivine, hornblende, biotite, and quartz minerals These rocks have disequilibrium textures which indicates an unstable state in the magmatic chamber.   Lavas in Bazman volcano show calc-alkaline to slightly tholeiitic trend. All rock samples of Bazman volcano have a weak negative anomaly in Eu, which is probably due to plagioclase differentiation or high oxygen fugacity. Based on Electron microprobe analyses, pyroxene, hornblende and plagioclase minerals have diopside, augite, hornbelend and Labradorite to Bytonite. Temperature-barometry based on these minerals showed that Bazman volcanic rocks were formed at 800 to 1200 ° C and a least 2 Kbar pressure and high oxygen fugacity.

Andesite rocks are one of the most common rocks in the continental margin, they are composed of plagioclase, biotite and hornbelend minerals. Unequilibrium textures such as Zoning, resorption, corrosion gulf, and sieve texture are common in these minerals. These evidences are found in the Bazman volcanic. Orogenic andesite shows enrichment of LIL elements relative to HFS elements. The pattern of normalized multi-element diagrams of Bazman rocks compared to the primary mantle has a relative enrichment of LIL elements relative to HFS elements and a negative anomaly in Ti and P elements. Also, pattern of rare earth elements normalized to Chondrite shows a relative enrichment of LRE elements relative to HRE elements with negative Eu anomaly. Thermo-barometry on minerals in Bazman andesitechr('39')s indicates that lava formed between 800 to 1200°C temperature and high fugacity. Minerals and whole rock geochemical evidences show that Bazman volcano is dependent to subduction environments and it seems formed by subduction of the Indian oceanic crust under the Iranian plate.

Bazman volcano is Stratovolcano that composed of andesite, basalt, andesite-basalt, dacite and rhyolite lavas with their pyroclastic equivalents, ignimbrite and tuff flows. The rocks of this volcano are calc-alkaline to slightly tholeiitic magmatic series and belonging to the active continental margin. These rocks have relative enrichment and negative anomalies in the elements, Nb and Ti, relative to the HFS elements. They are enriched in LRE elements relative to HRE elements and all rock samples show weak negative anomalies in Eu. Electron microprobe data on the plagioclase, pyroxene and hornblende minerals show that are labradorite to bitonite hyperstene and augite, and magnesium-chandelier, respectively. Thermo-barometry based on these minerals shows that Bazman volcanic rocks were formed between 800 and 1200 °C and least 2Kbar pressure and high oxygen fugacity. Bazman volcano was formed by subduction of the Oman oceanic crust under the central Iran.

The study area in the south of Deh Tah, Lut Block comprise Oligocene volcanic rocks which are composed of andesite, trachyandesite, dacite and rhyolite. These lavas have porphyric to porphyritic textures with abundant amphibole phenocrysts. Most of the Oligocene lavas display calck alkaline to high-K calck alkaline magmatic affinities. In the binary diagrams, the andesitic to trachyandesitic samples cluster far away from the trachydacitic, dacitic and rhyolitic samples suggesting that they were not afftected only by magmatic differentiation. The REE patterns and spider diagrams show enrichement in light ion litophile element (LILE) and hight field strength element (HFSE) depletion. The normalized patterns of the andesite to trachyandsite have a reliable overlap with oceanic island basalt (OIB). The patterns of the acidic lavas are correlated with the patterns of continental crust. These geochemical evidence indicate that the andesitic to trachyandesitic lavas are generated from partial melting of lithospheric mantle which previously metasomatized by subduction components (melt-fluids). Partial melting of the continental crust has an important role in generation of the acidic lavas. Based on geological setting and geochemical data, it seems that the Oligocene volcanic rocks formed in a post-collision zone, due to thinning of the continental lithosphere in Lut Block. This process is probably related to lithospheric delamination which occurs in a post-collisional zone in Lut Block, as a part of the Alpine-Hymalaya orogenic belt.

The Neogene volcanic rocks are exposed in south Arab abad, Lut block. The studied volcanic rocks covered Eocene and Oligocene volcanic lavas and Neogene evaporitic deposits. The base of the Neogene volcanic sequence made of breccia and tuff gradually covered by andesite, trachyandesite and dacitic lavas. These lavas have aphyric-phyric textures and microlitic to hyalomicrolitice in matrix. These lavas show calck alkaline magmatic trend. REE patterns and spider diagrams display enrichement in LREE and LILE relative to HREE and depletion in HFSE which like as subduction zone magmatism. In the tectonomagmatic diagrams they plot of subduction and post-collisions fields. Interpretation of the geochemical data indicates that the studied lavas probably produced from partial melting of lithospheric mantle which had previously enriched by subduction components (fluids and melt). Partial melting of crust, probably involved in generation of acidic lavas. It seems that in the Neogene period, lithosphere thinning induced partial melting of heterogeneous Sub Continental Lithospheric Mantle (SCLM). These processes consequently occurred by lithospheric delamination and asthenospheric upwelling.

The north Makran ophiolite in southeast of Iran, as a part of Tethyan ophiolites, is located between Lut and Bajkan-Durkan continental blocks. Among the rocks of this ophiolite sequence, diabase and basalt flows are present more abundant in the outcrops in the eastern part of the studied north Makran ophiolite. Structural, petrographic and geochemical evidences suggest distinct geodynamic setting for the formation of these rocks. Based on geochemical characteristics, diabase and basalts fall into two groups: In the first group, tholeiitic diabase and basalt flows represent MORB-like affinity, and the second group include calc-alkaline basaltic to dacitic lavas with arc environment and supra-subduction affinities. These two lava types represent two major magmatic events: 1) MORB-type magmatism resulted from Early Cretaceous rifting/opening between two continental blocks and resulted in the formation of tholeiitic diabase and basalt. LREE enrichment, low La/Yb and relatively high U/Th ratios suggest continental influence in their melt source, and 2) subduction-related magmatism, that formed calc-alkaline basaltic, andesitic and dacitic lavas in Late Cretaceous. LILE, LREE enrichment, Nb and Ta negative anomaly, low TiO2 concentrations and relatively high Ce/Pb ratio document subduction influence in their composition.

The studied area is located in the SE of Bam and Urumieh-Dokhtar Magmatic Arc. Based on petrographical and geochemical characteristics, studied rocks contain tonalite, granodiorite, granite and alkali granite. These rocks are metaluminous, weakly peraluminous, high-K, and calc-alkaline. The behavior of Y, Ba, Ce and Zr vs. SiO2 display the properties of the high temperature I-type granites. These granitoids plot in the field of VOG. Enriched LREE and LILE with depleted HFSE show characteristics of subduction related active continental margins. The ratios of Nb/U and Nb/La and Sm/Yb indicate the crustal contamination. Isotopic data and La vs. La/Sm diagram show the role of the lower crust and the old continental crust in magma evolution. According to the phenocrysts assemblage, REE pattern with negative Eu anomaly and La/Yb ratio to crustal thickness, studied rocks are fractionated from relatively dry magma which has undergone from shallow depths. Sm/Yb and La/Yb ratio display the mantle source is garnet-free source. The low to moderate degree of partial melting of garnet-free amphibolite is the source of the studied granitoids. Volatiles that is driven from subduction slab and melt of the subducted sediments play a significant role in the generation and evolution of their magma source.

The south Natanz volcanic zone located in the central part of Urumieh-Dokhtar magmatic arc and the north of Isfahan. The area is dominated by the Eocene volcanic rocks ranging from acidic to intermediate and relatively basic affinity. Petrologically, they consist of rhyolite, dacite, andesite, basaltic trachyandesite and basaltic andesite. Mineralogically speaking, except for the acidic rocks, the other rocks are mainly made of plagioclase and clinopyroxene up. According to EPMA, the composition of clinopyroxene and plagioclase is augite and andesine to bytownite. Having features such as zoning and sieve texture in phenocrysts of plagioclase, roundness, and corrosion gulf in minerals belonging to the volcanic rocks reflecting the existence of unequilibrium during magma solidification. Considering geochemical features of these rocks, we can realize that they are calc-alkaline with potassium from intermediate to high LILE enrichment, and negative Nb-Ti anomalies. On the spider diagram, primitive mantle- normalized with Pb-enrichment can be seen which may be attributed to crustal assimilation. The negative anomalies of Nb and Ti on the spider diagram reflect subduction process, the crustal involvement in magmatism processes, or an indication of deficiency of these elements at the origin, the stability of Nb-Ti bearing phases during partial melting or separating these elements in the course of fractional crystallization process. The chondrite- normalized REE pattern points to LREE enrichment in comparison with HREE. The volcanic rocks studied have been originated in a magmatic arc.