Petrological and geochemical characteristics of the Granitoid complex of astaneh, western Iran, from the point of beneficiation

The Granitoid Complex of Astaneh closed to Boroujerd belongs to the Sanandaj-Sirjan Zone (SSZ) in the western of Iran. It is elongated and parallel to the prevailing schistosity in the metamorphic rocks by the trend of NW–SE and consists of quartz diorites, granodiorites, monzogranites and acidic dikes (aplites and pegmatites). This complex is of sub-alkaline affinity; belong to the high-K calc-alkaline series, metaluminous to weakly peraluminous, and display features typical of I-type granites. Trace and rare-earth elements distribution patterns for the Astaneh granitoid rocks indicate a distinctive depletion with respect to primitive mantle in Nb, Eu, Sr, Ba, P and Ti relative to other trace elements and a greater enrichment in LILE compared to HFSE. These geochemical characteristics suggest that these rocks derived from a crustal source. The granitoid Astaneh has geochemical characteristics typical of arc intrusives and plot as volcanic arc granites on various discriminant diagrams. This granitoid is typical representatives of a volcanic arc environment, spatially related to an active continental margin. Probably, it is the result of the subduction of Neo-Tethyan oceanic crust below the Iranian microcontinent. All available data are compatible with the idea that these rocks represent the products of convergent margin processes during the Mesozoic

Environmental pollution and pattern formation of Harsin–Sahneh ophiolitic complex (NE Kermanshah—west of Iran)

193-204To determine and estimate the environmental impact of certain elements- 10 soil samples from various areas in these massifs have been investigated. The obtained results show that most of heavy and major elements were exceeding the permissible levels in soil samples in the study area. On the subject of soil quality, concentrations of elements Cr, Mn, Fe, Ca, Mg, Ca, Ni, and Zn are above permissible levels. Comparing the concentrations of elements with results of grain size analysis illustrates that the concentrations of Cr, Ni, Fe, Mg, and Co are positively correlated with sand fraction and the concentrations of Al, P, Mn, and Pb are directly proportional with clay fraction in soil samples. Petrographic evidence indicates that this ophiolitic sequence consists of both mantle and crustal suites. In this complex, generally lithologies include harzburgitic and lherzolitic peridotites, isotropic and mylonitic gabbros, dyke complex, basaltic pillow lavas, and small out crop of plagiogranite. The mineral chemistry of Harsin mafic rocks is island arc setting for this part of complex and geochemistry of mafic and ultramafic rocks of Sahneh region displaying P-type mid-ocean ridge basalt (MORB) nature

Petrology, Geochemistry and Tectonomagmatic Setting of Farmahin Volcanic Rocks (North of Arak)

Introduction The study area includes Alam Baghi, Vashaghan, Sar Band and Ghermez Cheshmeh and is located in the northeast of Farmahin and the southwest of Tafresh. Based on the structural subdivisions of Iran, the mentioned area is a part of Central Iran and the Urumieh-Dokhtar magmatic belt (Hajian, 1970). The studied volcanic rocks consist of trachybasalt, trachyandesite, basaltic andesite, andesite, dacite, rhyodacite, rhyolite, ignimbrite, tuff and tuffit in composition and in terms of age they belong to the middle and upper Eocene. It seems that the volcanic activities are related to folding and faulting in the studied area. On the other hand, in addition to causing orogenic activity, at the middle and upper Eocene (Ghasemi and Talbot, 2006), locally extensional regime has played a main role in volcanic eruption. Similar to this scenario happened in other areas such as Taft and Khizrabad in Central Iran (Zarei Sahamieh et al., 2008). Porphyritic, microlite porphyritic and microlitic are the main textures in these rocks. Mineralogically, they contain plagioclase, clinopyroxene, amphibole, quartz and biotite as the main minerals and zircon, apatite, and opaque minerals as accessories. Materials and methods The major and trace elements of mineral composition are determined by electron probe micro-analysis (EPMA) using a Cameca SX100 instrument in the Iran Mineral Processing Research Center (IMPRC). Moreover, the whole-rock major and some trace elements analyses for a few samples were obtained by X-ray fluorescence (XRF), using an ARL Advant-XP automated X-ray spectrometer. Results Based on EPMA analyses, plagioclase mineral in basaltic andesite and trachybasalt samples range from labradorite to bytownite in andesite and trachyandesite has oligoclase- andesine and in dacite, rhyodacite, rhyolite has an albite-oligoclase composition. In the Wo-En-Fs diagram, all clinopyroxenes show augitic and a lessor amount of clinoenstatite composition and in the Q-J diagram located in the Mg-Fe-Ca (Quad) field and in the 2Ti+Cr+AlVI vs. Na+AlIV diagram (Morimoto et al., 1988) located above on the Fe3+=0 line that indicate high oxygen fugacity during crystallization. Microscopic study on these rocks such as oscillatory zoning, resorption rims in plagioclase and the presence of basic inclusions suggest the occurrence of magmatic contamination on the parent magma. The presence of oxidized amfibool rims (in hornbelende as oxy hornbelende) indicate the high temperature of the magma at the time of eruption. According to the classification diagrams such as total alkaline vs. SiO2 (Irvine and Baragar, 1971) TAS (Le Bas et al., 1986) and tectonic discrimination diagrams (Pearce et al., 1984) samples are plotted in sub-alkaline, basaltic-andesite, andesite, dacite and rhyodacite, subduction and volcanic arc fields, respectively. The geochemical diagrams such as AFM are used for the identification of magma series and show that the studied rocks are calc-alkaline and A/NK vs. The A/CNK diagram shows the metaluminous to peraluminous nature. Incompatible and LIL elements such as Ba, K and Rb enrichment show that the contamination of magma with continental crust has occurred. The similarity between the REE patterns in all of the collected samples in Alam Baghi, Vashaghan, Sarban and Ghermez Cheshmeh areas suggest the same source for all of the volcanic rocks. Discussion The tectonic setting diagrams show that these rocks belong to the continental margin which has been involved in a subduction zone. The position of the samples on the major elements vs. SiO2 diagrams indicate that magma differentiation has occurred. Spider diagrams show a positive anomalous in Rb and a negative anomalous in Nb and Ti This phenomenon shows a contamination between the magma and the crustal rocks (Rollinson, 1993). Also, MORB-normalized incompatible element patterns of the Farmahin area show that the parent magma has been contaminated. It appears that assimilation and fractional crystallization (AFC) were the dominant processes in the genesis of the studied volcanic rocks. As a conclusion and according to field evidence and geochemical characteristics presented in this article, the studied area is composed of lava flows and pyroclastic rocks such as andesite, dacite, rhyodacite, ignimbrite, tuff and tuffits that cross cut by younger dykes and belong to the middle to late Eocene age (middle to upper Lutetien). According to Sm/Yb vs. Sm diagram (Aldanmaz et al., 2000), all the studied samples in terms of composition are similar to enriched mantle-derived melts that are generated by varying degrees of partial melting (10% - 20%) from a spinel lherzolite to spinel-garnet lherzolite source. Considering the evidences, all rocks in the studied area belong to the subduction zone and the parent magma originated from mantle and was contaminated with continental crust during eruption and rising. Acknowledgments The authors wish to thank the Journal Manager and reviewers who critically reviewed the manuscript and made valuable suggestions for its improvement. References Aldanmaz, E., Pearce, J.A., Thirlwall, M.F. and Mitchell, J.G., 2000. Petrogenetic evolution of late Cenozoic, post-collision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research, 102(1–2): 67–95. Ghasemi, A. and Talbot, C.J., 2006. A new scenario for the Sanandaj-Sirjan zone (Iran). Journal of Asian Earth Sciences, 26 (6): 683–693. Hajian, J., 1970. Geological map of Farmahin, scale1:100000. Geological Survey of Iran. Irvine, T.N. and Baragar, W.R.A., 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences, 8(5): 523–548. Le Bas, M.J., Le Maitre, R.W., Streckeisen, A. and Zanettin, B., 1986. A chemical classification of volcanic rocks based on the total alkali silica diagram. Journal of Petrology, 27 (3):745–750. Morimoto, N., Fabrise, J., Ferguson, A., Ginzburg, I.V., Ross, M., Seifert, F.A., Zussman, J., Akoi, K. and Gottardi G., 1988. Nomenclature of pyroxenes. American Mineralogist, 173(9–10):1123–1133. Pearce, J.A., Nigel, B., Harris, N.B.W. and Tindle, A.G., 1984. Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks. Journal of Petrology, 25(4): 956–983. Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Presentation and Interpretation. Longman scientific and technical, London, 352 pp. Zarei Sahamieh, R., Tabasi, H. and Jalali, M., 2008. Petrology and tectonomagmatic investigation of volcanic rocks of Ashtian. Journal of Science, Kharazmi University, 8(3):227–240. (in Persian with English abstract

Petrology, mineral chemistry and tectono-magmatic setting of volcanic rocks from northeast Farmahin, north of Arak

Introduction The study area is a small part of the Urumieh-Dokhtar structural zone in the Markazi province, located in the northeastern part of the Farmahin, north of Arak (Hajian, 1970). The volcanic rocks studied from the area include andesite, dacite, rhyodacite, ignimbrite and tuff of Middle to Late Eocene age (middle Lutetian to upper Lutetian) (Ameri et al., 2009). It seems that folding and faulting is caused in sedimentary basin and volcanic activities. On the other hand, except of orogeny maybe rifting had rule in eruption so that this case has seen in the other area such as Taft and Khezrabad in central Iran (Zarei Sahamieh et al., 2008). The oldest formation in the studied area is Triassic limestones. The dominant textures of these rocks are porphyritic, microlite porphyritic, microlitic and rarely sieve-texture. Sieve texture and dusty texture (dusty plagioclases) indicates magma mixing. Mineralogically, they contain plagioclases, clinopyroxenes, amphiboles, quartz and biotite as the main constituents and zircon, apatite, and opaque minerals as accessories. Plagioclases in the andesitic and basaltic- andesite rocks are labradorite, bytownite and anorthite (based on electron microprobe) .Moreover, plagioclases in andesitic rocks show that H2O is lesser than 2.5 precent. Amphibole is found in both plagioclases and groundmass. Materials and methods In this article are used different analyses methods such as XRF, ICP-MS and EPMA. Whole-rock major and trace element analyses were determined with ICP-MS method. The major and trace element composition of some rock was determined by electron probe micro-analysis (EPMA) using a Cameca SX100 instrument in Iran Mineral Processing Research Center (IMPRC). Moreover, whole-rock major and some trace element analyses for some samples were obtained by X-ray fluorescence (XRF), using an ARL Advant-XP automated X-ray spectrometer. Results Chemical data based on electron micro probe studies of minerals indicate the presence of labradorite, bytownite, anorthite as the plagioclases in volcanic rocks, as well as augite, pigeonite and clinoenstatite among the pyroxenes are abundant. Microscopic study of these lavas and pyroclastic rocks show evidences of magmatic contamination in the form of oscillatory zoning, resorption rims in plagioclase and presence of basic inclusions. The presence of oxidized amphibole rims (in hornblende) indicates the high temperature of the magma at the time of eruption. Based on geochemistry especially the ratio of Eu/Eu* is variable between liquid and solid phases. The calculated of this ratio in studied rocks show negative anomaly (Eu According to classification diagrams is used of different diagrams for example TAS/SiO2, R1-R2 and Zr/TiO2-Nb/Y. TAS/SiO2 diagram show that the rocks are of basaltic-andesite, andesite and dacite. R1-R2 diagram show these rocks are andesite, andesi-basalt, dacite and rhyodacite. Finally, based on Zr/TiO2-Nb/Y the rocks in area under study are andesite, basalt, dacite and rhyodacite type. The geochemical diagrams (such as AFM) for identify of mama series show that the rocks studied are calc-alkaline and A/NK-A/CNK show magma is peraluminous to metaluminous in nature. Enrichment of incompatible and LILE elements such as Ba, K and Rb show that contamination of magma with continental crust have been occurred in this area. Similarity between REE patterns in all samples is related to common source for all volcanic rocks in the studied area. Discussion The tectonic setting diagrams show that these rocks belong to the continental margin which have been involved in a subduction zone and belong to the orogenic andesite belt. The position of the samples on the major elements-SiO2 diagrams indicate that magma differentiation has been occurred. Spider diagrams show depletion and enrichment that the type of rocks in studied area have positive anomalous of Rb and negative anomalous of Nb and Ti, this phenomenon shows contamination between magma and crustal rocks (Ghasemi and Talbot, 2006; Rollinson, 1993). Comparison of spider diagrams normalized to chondrite or MORB also show that the parent magma has been contaminated. It appears that assimilation and fractional crystallization (AFC) were the dominant processes in the genesis of the studied volcanic rocks (Roozbehani and Arvin, 2010). As a conclusion and regarding to what we said in this article ,the area under study are included both lava and pyroclastic rocks such as andesite, dacite, rhyodacite, ignimbrite ,tuff and tuffits that cut by younger dykes and belong to Middle to Late Eocene age(middle Lutetian to upper Lutetian).There is no rocks older than Triassic age. Volcanic rocks have been occurred in two environments, dry and water together. From volumetric point of view, Aciditic and intermediate rocks such as dacite, rhyodacite and andesite are the most in the area under study (Ahmadian et al., 2010). Basitic rocks are a lesser amount than the others. Regarding to all evidences such as field works, structurally, texturally, mineralogically, geochemically and petrologically show that rocks in studied area belong to subduction zone and magma that created of these rocks have been originated from mantle and contaminated with continental crust during eruption and rising. Acknowledgments The authors wish to thank Journal Manager and reviewers who critically reviewed the manuscript and made valuable suggestions for its improvement. References Ahmadian, J., Bahadoran, N., Torabi, G. and Morata, M., 2010. Geochemistry and petrogenesis of volcanic rocks in Aroosan Kabood (north-east of Anarak). Journal of Petrology, 1(1): 103-120. (in Persian) Ameri, A., ashrafi, N. and Karimi qarebaba, H., 2009. Petrology, Geochemistry and tectonics environment of Eocene volcanic rocks in east of Herris, east Azerbayjan, north-west of Iran. Journal of geosciences, 18(71): 85-90. (in Persian) Ghasemi, A. and Talbot, C.J., 2006. A new scenario for the Sanandaj-Sirjan zone (Iran). Journal of Asian Earth Sciences, 26(6): 683-693. Hajian, J., 1970 . Geological map of Farmahin (1/100000). Geological Survey of Iran. Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Presentation and Interpretation. Longman scientific and technical, London, 352 pp. Roozbehani, L. and Arvin, M., 2010. Petrography, geochemistry and petrogenesis of ryolitic and andesitic rocks in Nasir Abad, south-west, Kerman .Journal of Petrology, 1(2): 1-16. (in Persian). Tabatabai Manesh, M., Sayed Safai, H. and Mirlohi, A.S., 2010. Study of mineralogy and effective process on volcanic rocks in Jahaq anticlinal (south of Kashan). Journal of Petrology, 1(2): 61-76. (in Persian) Zarei Sahamieh, R., Tabasi, H. and Jalali, M., 2008. Petrology and tectonomagmatic investigation of volcanic rocks of Ashtian. Journal of Science Kharazmi University, 8(3):227-240. (in Persian) <br

Comparison of formation conditions and contamination of the groundwater of the Shiraz and the Khorramabad basins in Iran by means of factor analysis

1160-1168Comparison of formation conditions and contamination of the groundwater of the two large basins using a great number of chemical elements and compounds (10 and more) is a rather complicated task. We have suggested a new method based on applying factor analysis. Using this method gives an opportunity to define the sources of pollution of the groundwater and compare the conditions of their formation on different territories. The method has tested in the study of chemical composition of the groundwater of the Shiraz and the Khorramabad basins of Iran

Study of mineralization in gholgholeh area based on SEM and fluid inclusion (southwest of saghez city—Iran)

The aim of this study is gold and its element mineralization in Gholgholeh area. The Gholgholeh area is located in 40 Km southwest of Saghez city and in northwest of Kordestan province. The case of study in the oldest rock-unit outcrops in the north of this area which belongs to Percambrian gneiss. Permian deposit mostly distributed in north, northeast and northwest of this area. The major types of alteration are composed of silicification, sulfidation, sericitization, chloritization and carbonatization. sercitization and choritization are the most. SEM and mineralography studies indicate occurrence of sulfide mieralization especially Au sulfides which appears in two generations. On the basis of SEM studies, little Ag and As are observed. There is no gold in calcite. Primary mineral consist of: pyrite, marcazite and calchopyrite, and secondary minerals are pyrite, coveline and realgar. On the other hand, fluid inclusion studies shows 350ºC temperature in gold formation. Evidence like Parageneses, elements, gangue and alteration around mineralization area all indicate the presence of monometal gold vein ore deposit of quartz vein type replaced by gold vein in cracks which are depended on this structure

Geochemistry and mineral chemistry of Shahabad gabbroic intrusion, NW Nourabad, Lorestan province

The Shahabad gabbroic intrusion, with NW-SE trend cropped out at the boundary of Zagros and Sanandaj-Sirjan zones is composed of olivine gabbro, orthogabbro and troctolite. Plagioclase, clinopyroxene and olivine are the main minerals; and magnetite, titanomagnetite and serpentine are minor and secondary minerals. Microprobe analyses of the minerals show that plagioclase is labradorite, pyroxene diopsidic augite and olivine, chrysolite. The rocks appear to have calc-alkaline and metaluminous nature. The plots of some trace elements and composition of clinopyroxenes in the tectonic discrimination diagrams indicate a volcanic arc environment. In addition, spider diagram pattern of elements shows Sr enrichment and Ti, Nb, Zr and P depletion, typical characteristics of volcanic arc subduction related magmas. Furthermore, close similarity between the patterns of spider diagram for the Shahabad pluton with those of Andean basic rocks suggests that the Shahabad calc-alkaline basic magma may have formed in a subduction environment. Based on geological, geochemical and mineralogical features, formation of the gabbros, as a part of ophiolite mélange, is attributed to a suprasubduction system

Geochemistry and Petrogensis of Mafic Dykes of Zarrin District, NE Ardekan, Central Iran

Zarrin Mafic dikes, which outcrop in the Western Yazd block, Central Iran, trending NW - SE, emplaced into the Zarrin granitoid. They are sub-alkaline gabbro; characterized by intergranular and mylonitic foliated texture. Geochemical data reveal the Zarrin mafic dikes are from the partial melting lithospheric mantle, a spinel-peridotitic source. Furthermore, they are characterized by 87 Sr/86 Sr ratio of (0.7044-0.7028) and 144 Nd/143 Nd ratio of (0.5123- 0.5122), that consistent with the derivation from a lithospheric mantle. Their primitive mantle normalized trace elemental patterns display enrichment in LILEs compared to HFSEs, and positive Rb, Ba, and U but negative Ta, Nb, Th, and Zr anomalies, carrying characteristics subduction-related magmatism and metasomatism by subduction-related fluids. The petrogenesis of the Zarrin mafic dikes are related to melting of the lithospheric mantle, and upwelling asthenospheric mantle in the extensional basin which was associated with the subductio

Geochemistry and geochronology of Zarrin intrusion, NE Aredekan, Central Iran

Zarrin granitoid, with mostly metaluminous to slightly peraluminous, and I-type composition, outcropped in Yazd block, Central Iran. The U-Pb SHRIMP zircon age from Zarrin granitoid yields 557-567 Ma age consistent with the Late Neoproterozoic-Early Cambrian ‘Cadomian’ plutonism at northern margin of Gondwana supercontinent. The chondrite and primitive mantle normalized trace elements patterns show light rare earth elements (LREE) enrichment relative to heavy rare earth elements (HREE) and enrichment of large ion lithophile elements (LILE) relative to high field strength elements (HFSE), accompanied by negative anomalies in Nb, Ti, and Eu consistent with arc-related magmatism, associated with subduction of Proto-Tethys oceanic crust beneath the northern margin of Gondwana. Geochronological and geochemical data including inherited zircon age suggest the Zarrin granitoid originated from partial melting of relatively younger mafic crust and point to the existence of hidden Paleoproterozoic-Mesoproterozoic rocks in the lower continental crust of Iran