جستجوی مقالات مرتبط با کلیدواژه « p metamorphic complex » در نشریات گروه « زمین شناسی »

The Shafarud Metamorphic Complex is located in the northwestern part of Iran in the Alborz-Talesh Mountain range. Paleozoic metamorphism (Carboniferous-Permian) are the oldest rocks of this region. The eclogites of the Shafarud Metamorphic Complex are exposed as lenses of several meters in size along with serpentinite masses in the basal parts. The mineral assemblage of the eclogites includes garnet, pyroxene, amphibole, white mica, epidote, plagioclase, chlorite, quartz and sphene. SEM images and the results of electron probe micro-analyzer (EPMA) show the growth chemical zoning in garnet porphyroblasts. According to the calculation of the temperature-pressure pattern, using Jacobian transformation, the core and the rim of garnets have been formed respectively at temperature-pressure 600 ºC -18.2 Kbar (eclogite facies, ~60 Km) and 550 ºC- 7.5 Kbar (green schist facies, ~25 Km). According to the results of this study, the structural pattern of the eclogites of the Shafarud Metamorphic Complex is similar to the alpine type, during which the process of uplift and pressure reduction occurred in almost isothermal conditions due to a rapid uplift.

The Golmandeh Metamorphic Complex is located in the Central East Iranian Microcontinent. In this research, structural and microstructural studies have been performed to determine the nature of the deformation in the Golmandeh metamorphic complex. The presence of microstructures such as mica fish, rotating porphyroclasts, and the S/C structure all indicate the top-to-northeast sense of shear. Based on the dynamic recrystallization studies, the deformation temperature in the Golmandeh Metamorphic Complex is estimated between 500 and 650° C. This condition correspond to amphibolite metamorphic facies. Using the Rigid Grain Net (RGN) method, the mean kinematic vorticity number was estimated to be 0.75. Based on the results of kinematic studies, the deformation regime in the Golmandeh Metamorphic Complex was determined as a general shear with contribution of 55% simple shear and 45% pure shear component.

Based on field observation and petrographic evidence, by progress in metamorphic degrees, a wide variety of metabasites have formed following the metamorphism at amphibolite facies (metamorphism M1) in the east of Jandaq. Thermobarometry of plagioclase- amphibole pairs indicate temperature ranges were 642-692ºC  and 688-712 ºC for epidote amphibolites and garnet amphibolite, respectively, in a pressure range of 8 and 11 Kbar, correlating with transition from middle amphibolite to upper amphibolite facies. In addition to this metamorphic phase, petrographic signatures indicate further metamorphic phases concerning this region's geological phenomena. Based on brittle deformation in amphiboles, and epidote and quartz formation in their fractures, these rocks have undergone some degrees of retrograde metamorphism (<700 ºC; metamorphism M2) at greenschist to lower amphibolite facies. Rock foliation and mineral orientation, aggregate shape preferred orientation (ASPO) of titanite crystals along foliation, and syn-tectonic euhedral garnets indicate prograde metamorphism toward amphibolite-upper amphibolite facies (metamorphism M3). Finally, under greenschist facies condition, minerals such as chlorite and actinolite were formed in these rocks (metamorphism M4). The formation of chlorite and actinolite in the rims of the primary crystals shows that these rocks were finally affected by metamorphism at greenschist facies (M4 metamorphism).

Bajgan metamorphic complex is located at the southeastern termination of the Sanandaj-Sirjan zone in north of Makran. The metamorphic rocks, having igneous and sedimentary origins, are in tectonic contact with ophiolite assemblages and colored mélange. The rocks can be divided in four units based on lithological characteristics. These units are covered by Pliocene and Quaternary sediments. Structural study indicates the presence of three syn-metamorphic stages of deformation in ductile condition. The main structures elements are different generation of folds, foliation and lineation, each of them has been generated during a specific stage and superimposed on each other. The structural elements in this complex have emerged during subduction, ophiolite obduction and exhumation, respectively.

Three fundamental goals will be followed in the study of metamorphic terrains including: 1- study of fabric in metamorphic rocks in order to recognize the relationship between metamorphism and deformation, 2- the identification of thermodynamic conditions of metamorphism for evaluating the geothermal gradient, and 3- study of protolites of metamorphic rocks and the recognition of Paleo-tectonomagmatic setting of igneous rocks. Takab-Takht-e-Soleyman-Angouran metallogenic –metamorphic zone located parallel to the Zagros suture zone within the Alpine–Himalayan orogenic belt. Halab metamorphic sequence is located in the Eastern part of this zone. This metamorphic sequence is composed of pelitic, mafic and felsic schists intercalated with marble, mylonitic rhyolite and quartzite which are metamorphosed in amphibolite and green schist facieses. Takab-Takht-e-Soleyman-Angouran metallogenic –metamorphic zone is one of the most important metallogenic zones in Iran. The Zarshouran As–Au deposit, Aghdareh Sb–Au deposit and Angouran Zn–Pb deposit along with some Fe, Pb–Zn, Au, Cu and Mn mineralization were formed within this zone. Most of this mineralization was studied during the past years and valuable information is present about their geological and mineralization characteristics. However, geochemistry and tectonomagmatic settings of metamorphosed volcanic rocks (felsic and mafic schists) were not studied. This research can be divided into two parts including field and laboratory studies. Field studies include the recognition of different metamorphic rocks along with sampling from metamorphic rocks for laboratory studies. In this base, 40 samples were chosen for petrographic and analytical studies. Twenty thin sections were used for petrographic studies and recognition of metamorphic fabrics. For geochemical studies, thirteen samples from felsic and mafic schists were analyzed by XRF and ICP–MS methods in GSI and Zarazma laboratories. Mafic schists are one of the most important metamorphic rocks in the Halab area. Compositionally, these rocks include actinolite schist, hornblende schist and amphibole schist. Felsic schists are the other important rocks in the Halab metamorphic sequence. These rocks include albite-quartz schist, biotite-quartz schist, amphibole-biotite-quartz schist and mylonitic rhyolite. Geochemically, mafic schists show a similar composition to basalt, trachy-basalt, basaltic andesite and basaltic trachy-andesite while felsic schist show rhyolitic composition. All of these rocks have calc-alkaline to high-K calc-alkaline affinity.  Trace elements normalized by primitive mantle (McDonough and Sun, 1995) and NMORB (Gale et. al., 2013) for felsic schists indicate LILE enrichment along with negative HFSE anomaly and distinctive positive Pb anomaly. A similar pattern is observed for most of the mafic schists. Amphibole schists do not show LILE enrichment, as well as positive Pb and negative HFSE anomalies. Chondrite-normalized (McDonough and Sun, 1995) REE patterns for felsic schists demonstrate LREE enrichment along with negative Eu anomaly and flat HREE patterns. Most of the mafic schists have similar patterns without negative Eu anomaly. Amphibole schists indicate a flat REE pattern with less LREE enrichment and relative enrichment in HREE compared with other mafic schists. Comparison of Chondrite-normalized REE patterns of mafic schists with NMORB and EMORB patterns and island arc basalts (Gale et al., 2013) indicate that basic schists of Halab area have similar patterns to EMORB. Based on Ta/Yb vs. Th/Yb and Yb vs. Th/Ta discrimination diagrams, protolites of mafic schists were formed in within plate volcanic zone and active continental margin while protolites of felsic schists were formed within active continental margin. On the Nb/Yb vs. Th/Yb diagram, mafic schists belongs to subduction-unrelated setting and originated from mantle similar to OIB source.  Takab-Takht-e-Soleyman-Angouran metallogenic –metamorphic zone is considered as a micro-continent with similar features to Gondwana (Hajialioghli et al., 2007). The oldest outcrops of metamorphic rocks in this zone are the result of metamorphism of magmatic arc rocks with Neo-Protrozoic–Early Cambrian age (Saki, 2010). As it was mentioned before, mafic and felsic schists of the Halab area demonstrate calc-alkaline to high-K calc-alkaline affinity. High-K calc-alkaline rocks are usually formed in magmatic arcs and post collision setting and are less seen within plate setting (Bonin, 2004). Enrichment in LILE and LREE along with Nb and Ti negative anomalies in spider diagrams are indicators of subduction related magmas which are originated from enriched mantle by metasomatic fluids released from subducted slab (Wang and Chung, 2004). Geochemical characteristics of mafic and felsic schists of the Halab area indicate that the protolites of mafic schists originated from partial melting of metasomatized mantle by past subduction in an extensional setting within a magmatic arc. Felsic schists are the result of crustal partial melting by mentioned basaltic magma.

Soltanabad metamorphic complex cropped out in the ophiolitic range of NE Sabzevar. There is a distinict gneissic body in this complex associated with metabasite, serpentinite and adakitic intrusions. Quartz, albite, epidote, amphibole, garnet and chlorite are rock forming minerals of gneissic samples. On the basis of abundance of light and dark minerals, different types of felsic, intermediate and mafic gneisses are distinguishable. Average metamorphic conditions of gneisses from Soltanabad complex is calculated as 462 (±39)°C at pressure of 12.4 (±2.15) kb which can be predominant in hot thermal regime of a subduction setting. Whole rock chemistry of investigated gneisses indicates their plagiogranitic composition that produced by partial melting of mafic sequence of oceanic crust. Isotopic ratios of Hf from Zr and REE pattern confirm MORB affinity of these gneisses. The gneisses from Soltanabad metamorphic complex display considerable compositional similarity with plagiogranite fron Iran and Cyprus ophiolitic zones. Geochemical characteristics of these gneisses are comparable with plagiogranites of supra-subduction zone setting as well. Probably gneisses and blueschists of Soltanabad metamorphic complex represent plagiogranites and mafic rocks of Sabzevar oceanic lithosphere that have experienced subduction zone metamorphism.

Mahmoudabad metamorphic complex is a part of Sanandaj-Sirjan metamorphic zone that cropped out in SE Shahindezh. Metapelites are the main lithology of Mahmoudabad complex and there are restricted exposures of foliated and granoblastic metabasites present in this complex as well. Metabasites of this complex are investigated in this research. Metabasites display amphibole and plagioclase mineralogy that indicating amphibolite facies. Chemical composition of plagioclase is andesine and labradorite and amphibole is magnesiohornblende and tremolite. Thermobarometry results, that calculated by different methods, display temperature between 430 to 750 centigrade and pressure 6 to 13 kilo bars that are almost equivalent geothermal gradient between 20 to 25 centigrade per kilometer. According to the whole rock geochemical data, the amphibolites of Mahmoudabad complex are orthoamphibolite type and are mostly basaltic in composition. Geochemical signatures of these amphibolites are compatible with tectonic setting of continental back arc. Probably, Mahmoudabad complex amphibolites, are indication of mafic magmatism in the continental back arc setting, arisen from Neotethy oceanic basin seduction beneath continental lithosphere of Sanandaj-Sirjan, that have been experienced collision or continental active margin metamorphism.

Detailed microstructural analysis has been conducted in the Ghandab metamorphic Complex, which is one of the most important high temperature – low pressure regional contact metamorphism studied areas in Iran. Textural evidence suggests the sequence of growth of minerals with increasing metamorphic grade and during development of a crenulation foliation. The sequence of mineral growth is considered to be cordierite, andalusite, garnet, and sillimanite. The first foliation (S1) is preserved largely as inclusion trails in cordierite porphyroblasts. However, garnet and andalusite porphyroblasts are syndeformation crystals and grow during development of crenulation-foliation of S2. According to textural evidence, sillimanite produced late in the thermal history of metamorphism and deformation

As a part of Takab Metamorphic Complex (TMC), Belqeis Mountain has a variety of ýmetamorphic rocks including orthogneiss, pelitic schists, meta-ýultramafics and mafic rocks and dolomitic marbles. This complex was metamorphosed, faulted and folded ýduring Late Neoproterozoic-Early Cambrian Pan-African orogeny and invaded by ýgranitoid pertinent to the subduction of the Neo-Tethys oceanic crust beneath the ýIranian crust during Tertiary. Geochemically, the protolith of orthogneiss of ýBelqeis Mountain is ýhigh K and has calc-alkaline affinity and both fractional crystallization and magma mixing have been incorporated significantly to produce the protolith of them. The pattern of trace elements normalized to chondrite and primitive mantle points to enrichment in LILE and LREE, depletion of HFSE and HREE and shows negative anomalies in Eu, Ba, ýNb, Sr, Ti and P. Depletion in HFSE was accompanied with enrichment of LILEs and ýLREEs indicating the generation of protolith in subduction setting related to active ýcontinental margins. Tectonic discrimination diagrams suggest a combination of volcanic ýarc and continental collision settings for the studied samples. There are many evidence including La/Nb>1 and relatively high values of several ratios such as Zr/Nb (14.7), Th/Nb (1.5), Ba/Nb (58), La/Nb (3), Ti/Zr (14.9), Nb/Ce (0.24) and (La/Sm)n (3.76),close to crust values, confirming that mantle was not incorporated solely but both crust and mantle sources were contributed in origin of these rocks. All aforementioned ýpoints in addition to occurrence of paleo-suture zone and ophiolitic ýrocks (i.e. serpentinites, meta-mafic and meta-ultramafic rocks) around these medium to ýhigh grade metamorphic rocks confirm that subduction of an oceanic lithosphere followed ýby collision in the study area. ý

Two different ages of Precambrian and Jurassic are considered for the Zayanderud metamorphic complex in the Najafabad and Chadegan geology maps, respectively. This disagreement has made these two maps to be the most incompatible adjacent maps. The metamorphic complex is nonconformably covered by fossiliferous Permian limestones suggesting a Pre-Permian age. This relative age is supported by 206Pb/238U zircon ages of Neoproterozoic for the cross-cutting mylonitic orthogneisses. In this paper we discuss the Jurassic age considered for protolith of the metamorphic and granitoid rocks in the Chadegan map as an misunderstanding in field observations. Also we argue that Ar/Ar Jurassic ages represent the time of metamorphism and do not reflect the protolith age.

The Deh-Salm metamorphic complex, including the various types of metamorphic rocks and a north-south trending sequence of the index-mineral zones, crops out associated with the felsic plutonic rocks in the eastern margin of the Central Iranian micro-continent, between the Sistan suture zone and the Lut block. Amongst the metamorphic rocks, metapelite from different parts of the complex is the most widespread. Several evidence suggest the occurrence of a progressive regional metamorphism associated with the sequence of metamorphic index minerals from the west to the east. Metamorphism of the metapelitic rocks at the greenschist facies was initiated by the garnet zone, continued to the staurolite, andalusite and sillimanite zones, and terminated at the higher orthoclase-sillimanite zone in the condition of the amphibolite-granulite facies transition. The results from the thermometry calculations, based on the Fe-Mg ratio for biotite and garnet pair in equilibrium provide new temperatures; the western part of the complex underwent the greenschist facies with a temperature between 450 to 550°C and the eastern part experienced amphibolite-granulite transitional facies under a temperature up to 750°C. Metamorphic conditions inferred by the study of the pelitic rocks and correlated to the other adjacent rocks show an Abukoma-type progressive metamorphism. It may be considered that the late-Jurassic regional metamorphism event, synchronous with the Shah Kuh granitization at the eastern margin of the Lut Block was occurred due to the subduction of the Neotethys ocean.

Asalem metamorphic complex consists mostly of metabasite, metapelite and serpentinite. Metabasites display metamorphic features of greenschist and blueschist facies. Greenschist facies rocks that found as both foliated and massive types contain mineralogical assemblage of actinolite, chlorite, albite and epidote. Blueschists contain mineralogical assemblage of sodic amphibole, epidote and phengite. Whole rock analyses of the metabasites indicate basaltic to andesitic composition with mainly calcalkaline nature of their protolith. According to the discrimination diagrams of tectonomagmatic setting, the protolith of investigated metabasites has been islands arc and somewhat mid ocean ridge. The patterns of rare earth elements and spider diagrams of the Asalem metabasites resemble to the basic and intermediate magmatism of islands arc or suprasubduction setting as well. Greenschists and blueschists facies rocks of the Asalem metamorphic complex have been probably equivalent to islands arc or young and hot oceanic crust of suprasubduction zone setting. This portion of oceanic basin unlike the subducted even and thick oceanic lithosphere of Paleotethys during accretion in the shallower levels of accretionary prisms, have underwent metamorphic conditions of blueschist and greenschist facies and finally gave rise to the formation of the metabasites of the Asalem metamorphic complex.

The Sanandaj-Sirjan zone is a NW-SE trending orogenic belt immediately north of the Zagros suture, which represents the former position of the Neotethys Ocean. This zone includes a Pan-African basement similar to the various terranes to the north in Central Iran. The crystalline basement is nonconformably overlain by the Paleozoic-Triassic platform sediments, which in turn are unconformably covered by sedimentary and volcanic strata of the Jurassic arc. The Cretaceous carbonates overlie the older rocks with a regional angular unconformity. The Chadegan high-P metamorphic complex exposed along the upper Zayanderoud and consists of quartz schists, amphibolites, gneisses, marbles and eclogites, and is nonconformably underlain by the fossiliferous Permian carbonates, suggesting a Pre-Permian age. In this paper we present new data including whole rock major and trace element compositions, mineral chemistry and radiogenic isotope data for the selected metabasites. The high field strength element (HFSE) abundances and Sr-Nd-Hf ratios suggest tholeiitic compositions with distinct within plate affinity rather than MORB. We also present new 206Pb/238U zircon age of 568.0 ± 5.3 Ma for a crosscutting orthogneiss reconfirming the Late Neoproterozoic age for the granitic protolith. We conclude that previously presented Ar-Ar ages for white-micas in eclogites and gneisses are indicative of metamorphic crystallization due to the regional plutonic arc activity. A comparison is made with the well-investigated Menderes Massif in Turkey where an orthogneiss-metabsite association with similar age and chemistry makes extensive exposures. We also conclude that this rock complex is extended from Zayanderoud to Khoy and beyond to the Menderes Massif and discuss the connection with the final amalgamation tectonics of the Gondwana near the beginning of the Cambrian Period.

In the eastern metamorphic complex of Khoy ophiolite, several chromitite lenses are exposed which some of them are exploited. Chromitites of Galvans area have been surveyed recently during exploration activities. There are two mineralization zones which are 150 meters apart other. The Zone 1 mineralization has chromites with banded textures and enclosed by dunitic host rock. The Zone 2 mineralization is a large lens composed of massive texture chromites. Both of them enclosed by mantle peridotites. Mineral chemistry studies on zone 2 chromites (chromitites) indicate that they have average Cr# and Mg# 40.90 and 77.45 respectively and are podiform, Alpine type with high Al2O3 content. Based on tectonic setting discrimination diagrams, these chromites (zone 2) were formed in the MORB setting. Parental melt chemistry calculation of these chromites (zone 2) demonstrates that it has Al2O3 (16.98-17.16 wt %) content and FeO/MgO (0.79-0.83) ratios. These features are consistent with Al2O3 content and FeO/MgO ratio of MORB-type melt.

Gasht metamorphic complex is situated in the Talesh mountains of western Alborz range. This metamorphic complex consists mainly of metapelite and metabasite. Metabasites display metamorphic conditions of amphibolite and greenschist facies. Mineralogical paragenesis of greenschists are amphibole, feldspar and epidot and clinopyroxene occures as accessory minerals. The amphibolites of Gasht metamorphic complex are both granular and foliated types. Rock forming minerals are andesin and magnesiohornblende and accessory minerals contain sphene, ilmenite and clinopyroxene. Biotite formed as a result of amphibole altration. Thermobarometry results, that calculated by different thermobarometry methods, show temperature rangs between 550 to 750°C and pressure between 6 to 8 Kb that are nearly equivalent to geothermal gradient of 30°C/Km. These metamorphic conditions and geothermal gradient are resemble to the adjacent metapelites. Whole rock chemistry of metabasites from Gasht metamorphic complex display geochemical characteristics of subduction setting basic magmas. Probably, greenschists and amphibolites of Gasht metamorphic complex are indicative of basic magmatic arc products that resulted of Paleotethys oceanic basin subduction beneath edge of  the Turan plate and has experienced continental active margin or collision metamorphism.

Delbar metamorphic complex is located in 130 Km south of Shahrood (Biarjmand area) in Northern margin of the central Iran zone. The varied metamorphic rocks including meta-psammite, meta-greywacke, meta-pelite, marble and amphibolite and mylonitized granites and leucogranites intrusions are exposed in this complex. The field and petrography evidences indicated the evolutions resulted of the increasing in temperature and pressure from phylites and mica-schists to garnet bearing gneisses in meta-pelitic sequence and from amphibole schist to ortho-amphibolite and garnet amphibolite in meta-basite sequence. The thermobarometry studies based on the garnet, amphibole and plagioclase minerals chemistry in the garnet bearing amphibolites demonstrate 529-693˚C temperature ranges and 9.6-12.9 Kbar pressure ranges indicating of amphibolite to upper amphibolite facies for meta-basites, which has reached to the partial melting initiation. The field and geochemical evidences indicate that the protolith of the studied amphibolites were diabase dykes and basic-moderate lavas. These rocks originated from the primary magmas which were depleted in Nb, Ti and Zr and enriched in Pb and LREE with the calc-alkaline nature. The primary magmas derived from sub-continental lithospheric mantle in the extensional back arc basin during late Neoperotrozoic- Early Cambrian in Central Iran.

A metamorphic complex containing green schist، mica schist and serpentinite exposed in the Asalem area (NW Rasht). The occurrence of blue schist facies rocks in this complex are reported here for the first time. Mineralogical paragenesis of metabasitic blueschists consists of glaucophane، epidote، chlorite and phengite while there are garnet، phengite، chloritoide and feldspar in the metapelitic rocks. The metamorphic conditions of these rocks calculated by THERMOCALC software، petrogenetic grids and conventional thermobarometrs، are 7 to 12 Kb and 350 to 550 ºC for pressure and temperature، Pressure and temperature conditions of metamorphism and protolith diversity (metapelite، marble، metabasite، serpentinite) of the Asalem metamorphic complex indicate that they were created in the Pacific Ocean-type accretionary prisms (B-type blueschists). The studied metamorphic complex likely originated along the Paleotethys suture zone، as a result of the subduction onset of the Paleotethys oceanic basin beneath the southern margin of Luarasia during Carboniferous.

Qatruyeh metamorphic complex in SW of Iran is located in NE of Nayriz in eastern border of the Sanandaj-Sirjan metamorphic zone. The complex consists of different schists, carbonate metamorphic rocks, quartzite, metasandstone and metavolcanics. Zagros fault movements appear as north-south Qatruyeh-Darehbid fault in the western part of the complex and is composed of a shear zone with carbonate mylonites as a main rock unit. In this research, the shear zone introduced and thermometry of deformation estimated based on twins of calcite in carbonate mylonites. Microstructure studies, based on morphology and twin width of the calcite crystals, show crystal- plastic deformation in calcite, which formed mostly mechanical e-twinning. The width of the calcite twins in studied samples range between 0.5-15 microns with density of 10 to 55 twins in millimeter. Based on experimental and mineralogical studies, temperature of the deformation estimated between 250 to 300 ˚C. Paragenesis of minerals in schists show that metamorphism developed up to green schist to lower amphibolite facies and followed by dextral sense of main faults of the area as dynamic metamorphism.

The Chadegan metamorphic complex is a WNW-ESE- trending antiformal structure located in Sanandaj-Sirjan structural zone, Iran. The inner core of the structure is made of orthogneiss, containing eclogitic lenses. Schists and marbles lie structurally above the orthogneiss and crop out in the external limbs of the antiformal dome. Two main deformational episodes have been documented in the schists and marbles. The first episode (D1 phase) produced S1 foliation, whereas the second episode (D2 phase) produced a penetrative S2 axial plane foliation, F2 folds, and a mylonitic fabric. Relicts of a high-pressure metamorphic mineral assemblage (M1) (phengite+ garnet + sodic-calcic amphibole) have been documented along S1 foliation. A later amphibolite-facies metamorphism (M2) occurred during D2 deformation phase. P-T estimates for M1 stage give an average pressure of 1.6 GPa and an average temperature of 550 °C, whereas M2 stage has been constrained at P = 0.34 – 0.48 GPa and T = 508 - 575 °C. 1 deformation phase and the associated highpressure metamorphic assemblage (M1 stage), documented in the Chadegan complex, were formed during the subduction stage, while the D2 deformation phase and M2 metamorphic blastesis were recorded during the exhumation stage; probably they occurred before the end of Cretaceous.

The Shanderman metamorphic complex, located in the west of Gilan Province and southwest of Bandar-e-Anzali, is composed of a variety of metamorphic rocks (including slate, schist, calk-schist, marble, serpentinite, metagabbro and eclogite). Based on petrologic studies, protoliths of these rocks have had ultramafic, gabbro-gabbro noritic and pelitic composition. Mineralogically, the metapelitic rocks contain biotite, chlorite, muscovite, andalusite and metabasitic rocks contain amphibole, garnet, olivine, pyroxene and serpentine. Predominant texture of the rocks is porphyrolepidoblastic or nematoblastic. Zr/Y ratio of these rocks, which is less than 3, shows that they are similar to oceanic island arc rocks. Negative anomalies of Ti, P, and K and positive anomaly of Pb (appeared in spider diagrams) are evidences for their relation to crustal assimilated subduction zones. Distribution pattern of trace elements such Th, Hf, La, and U in the studied metapelites indicates a transition from passive margin towards island arc. The characteristics of the studied assemblage show that it was developed in an oceanic passive margin and then evolved within subduction zone.