Journal of Economic Geology

299-324

Authors: Elham Hashemian, Hemayat Jamali and Jamshid Ahmadian

Introduction The Tappeh-Khargoosh area is located at the 15 km SW of Ardestan, in the middle section of the Urumieh-Dokhtar magmatic arc (Aghanabati, 2004). Exploration in the study area began in 2006 by Kani Pajohan-e- Spadana Company and continued in detail by the Ardestan Copper-Gold Company. Their exploration activities consist of preparing the geological map (1:5000 in scale), drilling trenches and boreholes. Also minor extraction has been done. In this paper, our focus is on mineralogy, alteration, geochemistry and fluid inclusion of the Tappeh-Khargoosh deposit for determining the genesis of mineralization. The results of this study can be used for more exploration in the study and adjacent areas. Methodology Samples collected along a traverses perpendicular to the mineralized veins and their alteration haloes. The geometry, morphology, mineralogy and texture of mineralization were examined. After careful microscopic studies, 7 samples were analyzed by the XRF method in the laboratory of the Tarbiat Modarres University and Iranian Mineral Processing Research Center (IMPRC) in Karaj. Six thin-polished sections and 8 polished sections were examined. Also, 32 samples of mineralized and altered zones were analyzed by Inductively Coupled Plasma with optical emission spectrometer (ICP-OES) in IMPRC. Six samples were analyzed for gold by Atomic Absorption Spectroscopy (A.A.S) method in the Kimia Pajoh Alborz laboratory. Three double polished sections prepared from mineralized quartz vein and micro thermometric studies had been analyzed by a model HF-S90 microscope in the University of Isfahan. For detail understanding of mineral composition and determination of some fine and rare minerals, the electron microprobe analyzing (EMPA) technique (model SX100) is used in IMPRC. Discussion and results The Tappeh-Khargoosh deposit consist of quartz vein and veinlets which occur as open space filling in Eocene andesite and dacite. The mineralized veins mainly occur in the fault zones. The subparallel fault systems of dextral strike sleep Qom-Zefreh crustal scale fault (Tajmir Riahi et al., 2012) has had the main role in localization of mineralizing fluids. The alteration mainly consist of silicificaion, propylitization with minor sericitization and argillization represented as vein-veinlets, dissemination and pervasively in host volcanics. These alteration assemblages are indicative of near neutral to little alkaline hydrothermal fluids (Simmons et al., 2005). The silicic alteration has occurred in a wide range of pH and temperature, while the argillic alteration has occurred in low temperature and a wide range of pH. So where the silicic and argillic alterations have occurred together, the temperature of the causing fluid must be lower in the range of clay mineral stability field (Robb, 2005). The fluid inclusion in the quartz shows the low temperature (137-194˚C) and low to medium salinity (4-12.5 %) which coincide with low to medium sulfidation epithermal deposit conditions. According to fluid inclusion data, bisulfides were the main ligand for metals transportation. The absence of halite/sylvite daughter minerals in fluid inclusions and low salinity of fluid inclusions show that the chloride complexes not act as effective ligands. Opposed to high sulfidation epithermal deposits in which the magmatic waters are common, in the low sulfidation type, the meteoric waters are dominant (Foster, 1991; Vahabi Moghadam, 1993). Dilution by cold and low salinity meteoric water has the main role in mineral deposition. Pyrite, chalcopyrite, bornite, chalcocite and native gold are the primary minerals and hematite, goethite, covellite, chalcocite, cuprite, malachite, chrysocolla, azurite and atacamite are the secondary minerals, which have occurred as veinlets, open space filling, colloform, amygdal filling and dissemination in quartz vein and host rocks. Fine grain gold had be seen in the colloidal secondary Fe-oxides, which indicate that the gold probably occurred primarily in sulfide minerals and was released in the supergene process. According to microprobe analysis, Ag was measured as impurity in chalcocite. These features coincide with high correlation coefficient between precious metals and copper. So, the Cu can be used as a pathfinder element for gold exploration in this and adjacent areas. The abundance of Cu-bearing secondary minerals in the surface, indicate that the Cu has not leached effectively as a result of the little amount of pyrite and aridity of the area. In this condition, Cu which was created by oxidation of primary Cu minerals was fixed in the surface as silicate, carbonate and oxide minerals (Chavez, 2000). Geology, geometry, texture and structure, geochemistry, alteration schema, fluid inclusion and mineralogical data of the Tappeh-Khargoosh make it similar to low sulfidation (L.S) epithermal deposits. References Aghanabati, A., 2004. Geology of Iran. Geological Survey of Iran Publications, Tehran, 709 pp. (in Persian) Chavez, W.X., 2000. Supergene oxidation of copper deposits: Zoning and distribution of copper oxide minerals. Society of Economic Geologists Newsletter, 41(1): 10–21. Foster, R.P., 1991. Gold metallogeny and exploration. Springer, London, 431 pp. Robb, L., 2005. Introduction to ore- forming processes. Blackwell Publication, Australia. 373 pp. Simmons, S.F., White, N.C. and John, D.A., 2005. Geological characteristics of epithermal precious and base metal deposits. In: J.W. Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richard (Editors), Economic Geology, 100th Anniversary Volume: 1905-2005. Society of Economic Geologists, Littleton, Colorado, pp. 485–522. Tajmir Riahi, Z., Beigi, S., Safaei, H. and Nadimi, A., 2012. Identification active faults and seismic tectonic Shahreza area. 31th Geosciences Conference, Geological survey and mineral explorations, Tehran, Iran. (in Persian) Vahabi Moghadam, B., 1993. Petrographic and petrology metamorphic- magmatic rocks south of Nain. M.Sc. Thesis, University of Tarbiat Moalem, Tehran, Iran, 250 pp.

355-379

Authors: Ahmad Jamshidzaei and Ghodrat Torabi

Introduction The “adakite” term was used for the first time by Defant and Drummond (1990) to display Cenozoic arcs igneous rocks with intermediate composition (SiO2> 56 wt.%), which were produced by partial melting of subducted oceanic crust. The adakites are series of intermediate to acidic rocks, with composition range from hornblende-andesite to dacite and rhyolite; and basaltic composition are lacking. In adakitic magmas, phenocrysts are mainly plagioclase, hornblende and biotite; while orthopyroxene and clinopyroxene phenocrysts are known only in mafic andesites (Calmus et al., 2003). Geochemically, adakites are identified with SiO2> 56 wt.%, Al2O3> 15 wt.%, MgO< 3 wt.%, Sr> 400 ppm and enriched LILE and LREE and depleted Y and HREE (Y< 18 ppm, Yb< 1.9 ppm) and high ratios of Sr/Y> 40 and La/Yb> 20 (Castillo, 2006 and Castillo, 2012). By using geochemical data, adakites were classified into high silica adakites (HSA, SiO2> 60 wt.%) and low silica adakites (LSA, SiO2< 60 wt.%) main groups. The high silica adakites were produced by partial melting of subducted oceanic crust basalts and the resulting melts also interact with peridotite during their ascent through the mantle wedge. While, low silica adakites were produced by melting of mantle peridotite that were metasomatized by melts resulting from slab (Martin and Moyen, 2002). The intrusion bodies with porphyritic texture has been studied and reported in different areas (e.g. Lan et al., 2012; Zhang et al., 2015). This intrusion bodies are often in a stock shape and the texture is porphyritic due to fast crystallization. The study area (Kuh-e- Godar-e Siah) is located in southwest of Jandaq (northeast of Isfahan province) and northwest of Central-East Iranian Microcontinent. The quartz monzodiorite intrusion with stock shape cross cutting by Eocene dykes swarm with trachy andesitic composition. In this paper, the petrology and chemical characteristics of quartz monzodiorites and trachy andesitic dykes are discussed. Material and methods The chemical compositions of minerals from quartz monzodiorites and dykes were conducted by a JEOL JXA-8600 (WDS) electron probe microanalyzer (EPMA) at the Kanazawa University, Japan. Analyses were performed by an accelerating voltage of 20 kV and a beam current of 20 nA. The Fe2+ and Fe3+ contents of minerals were calculated by assuming mineral stoichiometry. The Fe2+# and Mg# parameters of minerals are Fe2+/(Fe2++Mg) and Mg/(Mg+Fe2+) atomic ratios, respectively. Representative chemical analyses of the minerals are listed in Table 1 and 2. To obtain whole rock chemical data, eighteen samples of the studied rocks were analyzed at the ALS-Mineral Company of Canada, by a combination of inductively coupled plasma spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) methods. The whole rocks geochemical data are presented in Table 3 and 4. Also, X-ray diffraction analyses were carried out in order to typify the K-feldspar mineral using an XRD D8 ADVANCE, Bruker machine, at the Central Laboratory of the University of Isfahan. The FeO and Fe2O3 concentrations are recalculated from Fe2O3*, using recommended ratios of Middlemost (1989). Mineral abbreviations are from Whitney and Evans (2010). Results and discussion The main texture in quartz monzodiorites is porphyritic; and Eocene dykes are granular, intergranular and porphyritic in texture. The quartz monzodiorites consist of plagioclase (albite), sanidine, quartz, biotite, muscovite, chlorite, magnetite, calcite and apatite. The minerals in trachy andesitic dykes are plagioclase (andesine and labradorite), clinopyroxene (diopside and augite), sanidine, phlogopite, quartz, amphibole, magnetite, calcite and apatite. The chondrite-normalized REE patterns and primitive mantle-normalized multi-elemental diagram of the quartz monzodiorites and trachy andesitic dykes show enrichment in LREE and LILEs and depletion in HFSEs such as Ta, Nb and Ti. There is no evident positive or negative anomaly of Eu. Petrographical and geochemical characteristics of quartz monzodiorites and trachy andesitic dykes show that these rocks have been derived from different sources. The quartz monzodiorites have high content of La/Yb= 17.49-41.89, SiO2= 64.60-68.80 wt.%, Sr= 434-1855 ppm, Sr/Y= 53.58-168.63 and low content of MgO= 0.16-1.10 wt.%, Y< 11 ppm and Yb< 0.95 ppm that show characteristics of high silica adakites which have been produced by melting of subducted oceanic crust. The trachy andesitic dykes have La/Yb= 33.45-59.76, SiO2= 53.40-57.60 wt.%, Sr= 859-2050 ppm, Sr/Y= 50.82-125, MgO= 1.93-4.53 wt.%, Y< 13.8 ppm and Yb< 1.14 ppm, which display characteristics related to low silica adakites, produced by melting of metasomatized mantle peridotite. Acknowledgments The authors thank the University of Isfahan for financial supports. References Calmus, T., Aguillon-Robles, A., Maury, R.C., Bellon, H., Benoit, M., Cotten, J., Bourgois, J. and Michaud, F., 2003. Spatial and temporal evolution of basalts and magnesian andesites (“bajaites”) from Baja California, Mexico: the role of slab melts. Lithos, 66(1): 77–105. Castillo, P.R., 2006. An overview of adakite petrogenesis. Chinese Science Bulletin, 51(3): 257–268. Castillo, P.R., 2012. Adakite petrogenesis. Lithos, 134(5): 304–316. Defant, M.J. and Drummond, M.S., 1990. Derivation of some modern arc magmas by melting of young subducted lithosphere. Nature, 347(6294): 662–665. Lan, T.G., Fan, H.R., Santosh, M., Hu, F.F., Yang, K.F., Yang, Y.H. and Liu, Y., 2012. Early Jurassic high-K calc-alkaline and shoshonitic rocks from the Tongshi intrusive complex, eastern North China Craton: implication for crust–mantle interaction and post-collisional magmatism. Lithos, 140(2): 183–199. Martin, H. and Moyen, J.F., 2002. Secular changes in tonalite-trondhjemite-granodiorite composition as markers of the progressive cooling of earth. Geology, 30(4): 319–322. Middlemost, E.A., 1989. Iron oxidation ratios, norms and the classification of volcanic rocks. Chemical Geology, 77(1): 19–26. Whitney, D.L. and Evans, B.W., 2010. Abbreviations for names of rock-forming minerals. American Mineralogist, 95(1): 185–187. Zhang, J.Q., Li, S.R., Santosh, M., Wang, J.Z. and Li, Q., 2015. Mineral chemistry of high-Mg diorites and skarn in the Han-Xing Iron deposits of South Taihang Mountains, China: Constraints on mineralization process. Ore Geology Reviews, 64(1): 200–214.

403-424

Authors: Tayebeh Ramezani, Mohammad Maanijou, Sina Asadi, David Lentz and Naser Pirouznia

Introduction Nowadays, more than half of the word’s copper production is obtained from porphyry copper deposits, large (greater than 100 Mt), low- to moderate-grade, disseminated, stockwork-veinlet, carrying at least trace elements, such as molybdenum, gold, and silver (Sillitoe, 1972). Porphyry Cu systems are related to granitoid porphyry intru¬sions and adjacent wall rocks and most of them form at convergent plate margins (John et al., 2010). The deposits are often localized within calc-alkaline porphyry magmatic systems in subduction zone settings. Some PCDs have been formed in post-subduc¬tion settings. Ahar-Arasbaran metallogenic zone is one of the most productive metallogenic zones in Iran. Mineralization in the area is mainly associated with Tertiary magmatic events. In order to perform a comparative study of mineralization, Sungun and Kighal porphyry copper deposits (PCDs) were selected. The Sungun copper deposit is located in the north Varzaqan and the Kighal copper deposit lies 10 km to the south of the Sungun PCD (Calagari, 2003; Calagari, 2004). As recent studies show there are some similarities between the Sungun and Kighal deposits in terms of the parent intrusions, the host rocks, age and geological setting. However, the grade of copper in the Sungun PCD is 0.62 % Cu and in the Kighal PCD is 0.2 % Cu. Therefore, what are the key factors that have made the Kighal PCD sub-economic? Material and methods Geochemical, fluid inclusion, and mineralogical studies were done on collected samples of the two porphyry copper deposits. In order to mineralogically study the Sungun and Kighal PCDs, 100 thin and polished thin sections were prepared. Eleven doubly polished sections of different quartz veins of the two PCD borehole samples were prepared for fluid inclusion studies. The measurements of 205 fluid inclusions were conducted at the Iranian Mineral Processing Research Center (IMPRC) by ZEISS microscope and Linkam TMH600, at temperature limits of -196 to +600 °C. The precision was ±0.6 °C at 414 °C (melting point of Cesium nitrate), and ±2°C at -94.3 (melting point of n-Hexane). SPSS 17 and Flincor computer programs (Brown, 1989) were used for data analysis. Discussion and Results In addition to some similarities of parent intrusions and host rocks (Hassanpour, 2010), there are similar fluid inclusion types and even nearly identical salinity and homogenization temperatures in these deposits (Simmonds, 2013). However, some differences in geochemical and mineralogical features, such as different low zonality index, less sulfide minerals and CO2 contents of the Kighal PCD, are notable. Some researchers have pointed out erosion (Hassanpour, 2010) and uplifting (Simmonds, 2013) as the main reasons for the sub-economic nature of the Kighal (non-productivity), comparison of Moho depth in the two deposits shows a greater crustal thickness in the Sungun PCD area (Fig. 10). The thickness of the lower crust is thought to be critical for governing arc mineralization potential, because it leads to an increase of the amount of water, metal, sulfur in adakitic magma forming arc-related bodies that is known to affect the origin of more productive (economic) porphyry copper deposits. Also low-CO2 fluid inclusions of the Kighal can have originated from a CO2-rich fluid immiscibility at depth (Simmonds, 2013). Lack of CO2 can inhibit (delays) bulk volatile saturation and in turn boiling, which influences the efficiency of metal removal from melt as well (Candela, 1997). CO2 contents of mineralizing fluids is important in increasing of pH during boiling event and ore deposition. The non-productivity of the Kighal PCD may have resulted from all these factors. Acknowledgement This work was supported by Bu-Ali Sina University and Iranian Mines and Mining Industries Development and Renovation Organization (IMIDRO). The authors would like to thank of the Sungun and Ahar copper companies. Special thanks to all the staff for their kind help. Thanks to the reviewers for their suggestions. References Brown, P.E., 1989. FLINCOR; a microcomputer program for the reduction and investigation of fluid-inclusion data. American Mineralogist, 74(11): 1390–1393. Calagari, A.A., 2003. Stable isotope (S, O, H and C) studies of the phyllic and potassic–phyllic alteration zones of the porphyry copper deposit at Sungun, East Azarbaidjan, Iran. Journal of Asian Earth Sciences, 21(7): 767–780. Calagari, A.A., 2004. Fluid inclusion studies in quartz veinlets in the porphyry copper deposit at Sungun, East-Azarbaidjan, Iran. Journal of Asian Earth Sciences, 23(2): 179–189. Candela, P.A., 1997. A review of shallow, ore-related granites: textures, volatiles, and ore metals. Journal of Petrology, 38(12): 1619–1633. Hassanpour, S., 2010. Metallogeney and mineralization of Cu-Au in Arasbaran Zone, NW of Iran. Ph.D. Thesis, Shahid Beheshti University, Tehran, Iran, 320 pp. John, D., Ayuso, R., Barton, M., Blakely, R., Bodnar, R., Dilles, J., Gray, F., Graybeal, F., Mars, J. and McPhee, D., 2010. Porphyry copper deposit model, chap. B of Mineral deposit models for resource assessment, US Geological Survey Scientific Investigations Report, 169 pp. Sillitoe, R.H., 1972. A plate tectonic model for the origin of porphyry copper deposits. Economic geology, 67(2): 184–197. Simmonds, V., Calagari, A.A. and Kyser, K., 2013. Fluid inclusion and stable isotope studies of the Kighal porphyry Cu–Mo prospect, East-Azarbaidjan, NW Iran. Arabian Journal of Geosciences, Fluid inclusion and stable isotope studies of the Kighal porphyry Cu–Mo prospect, East-Azarbaidjan, NW Iran. Arabian Journal of Geosciences, 8(1): 1–17.

449-470

Authors: Masumeh Sargazi and Ghodrat Torabi

Introduction Granitoids are the most common igneous rocks that are found in all parts of the continental crust and play an important role in the formation and evolution of the Earth’s continental crust (Clarke, 1992). Granitoid plutons contain useful information on factors and processes related to their generation and differentiation (Castro, 2013). The wide range of sources and processes that may be involved in the formation of granitoids is reflected in their compositional range. Although yet there is a long way to achieve a consensus about the origin of granite, different interpretations of the geochemical granitoid data represents geological understanding of the complexities of these rocks. Large parts of Iran and Central - East Iranian Microcontinent (CEIM) structural zone have suffered from the Eocene granitoid magmatism. Toveireh granitoid intrusive body cropped out in the southwest of the Jandaq city (NE of Isfahan Province) and is one of the Eocene granitoid bodies. It is hoped that this mineralogical and petrological research will be useful in understanding the nature of Eocene acidic magmatism of Central Iran. Material and methods Chemical analyses of minerals in the Toveireh granodiorites were carried out by a JEOL JXA-8800R (WDS) electron probe micro-analyzer (EPMA) at the Cooperative Center of Kanazawa University, Kanazawa, Japan. The analyses were performed under an accelerating voltage of 20 kV and a beam current of 20 nA with a counting time limit of 40 seconds. Natural minerals and synthetic materials were used as standards. The ZAF program was used for data correction. The amounts of Fe2+ and Fe3+ contents of minerals were estimated by assuming ideal mineral stoichiometry in structural formula. Mineral abbreviations in petrographic photomicrographs and tables are taken from Whitney and Evans (2010). Results and discussion Petrographic studies show that the Middle Eocene Toveireh granitoid intrusive consists of granodiorite and granite. Granodiorites are coarse grained, mesocratic and have microgranular mafic enclaves in hand specimen. They are composed of plagioclase, amphibole, quartz, orthoclase and biotite. Accessory minerals are zircon, apatite, sphene and magnetite. Chlorite, actinolite, epidote and sericite are present as the secondary minerals. In the study area, the most dominant texture of the granodiorites are granular but graphic, perthite, anti-perthite, anti-rapakivi textures are common. The plagioclase (An0.8-48) occurs mainly as medium to coarse grains, subhedral, with zoning and polysynthetic twinning that represent varying degrees of saussuritization. Quartz occurs commonly as medium to fine anhedral grains. Graphic texture intergrowths of quartz and feldspars are present. Graphic texture possibly indicate rapid and simultaneous crystallization of quartz and K–feldspar from an under-cooled liquid at shallow depths (Clarke, 1992; Barker, 1983). Hornblende is present as subhedral to anhedral grains and in some cases partly altered to chlorite and actinolite. Biotites are subhedral and sometimes altered to chlorite, titanite and epidote. Based on mineral chemistry data, amphiboles in the investigated plutons are calcic in composition and classify as magnesio-hornblende and actinolite. Amphiboles are characterized by Mg# 0.67 to 0.47 and present geochemical features of subduction zone-related amphiboles. Biotite is characterized by variable and high Fe contents, with Fe# [Fe2+/(Fe2+ + Mg)] ratios between 0.52 to 0.60. Using the nomenclature scheme of Foster (1960), they are Mg-biotite, and have composition range of the calc-alkaline granites among the different granitoid suites in discriminative trend defined by Abdel-Rahman (1994). Chlorites are brunsvigite in composition and have negligible K2O and TiO2 but show similar Fe/(Fe+Mg) ratios with amphibole and biotite. Therefore, it can be concluded that they are alteration products of mafic minerals. Chlorite alteration temperature is estimated to be 245 to 262°C from chlorite geothermometry. The chemistry of hornblende and biotite imply that Toveireh granodiorites have I-Type nature and are products of crust-mantle, mixed-source magma crystallization. Barometry calculations of amphiboles indicate that these rocks were emplaced at an average pressure of 1-1.5 kbars corresponding to approximately 3.5-6 Km depth. Plagioclase-amphibole and biotite thermometry suggests an equilibrium temperature of 700 to 800°C. Estimation of Oxygen fugacity by Fe# of amphibole and biotite indicate high value of Oxygen fugacity (+1< ∆FQM < +2.0) and suggest that the Toveireh granitoids belong to the magnetite-series of granites. Petrography and mineral chemistry of the studied rocks indicated their subduction-related tectonic setting. Acknowledgments The authors thank the University of Isfahan and Kanazawa University for financial supports and laboratory facilities. References Abdel-Rahman, A., 1994. Nature of biotites from alkaline, calcalkaline and peraluminous magmas. Journal of Petrology, 35(2): 525–541. Barker, D.S., 1983. Igneous rocks. Prentice Hall, New Jersey, 417 pp. Castro, A., 2013. Tonalite –granodiorite suites as cotectic systems: A review of experimental studies with applications to granitoid petrogenesis. Earth-Science Reviews, 124: 68–95. Clarke, D.B., 1992. Granitoid Rocks. Chapman and Hall, London, 283 pp. Foster, M.D., 1960. Interpretation of the composition of the trioctahedral micas. United States Geological Survey Professional Paper, 354(B): 11-49. Whitney, D.L. and Evans, B.W., 2010. Abbreviation for names of rock-forming minerals. American Mineralogist, 95(1): 185–187.

497-535

Authors: Seyed Nematollah Haghighi Bardineh, Reza Zarei Sahamieh, Hassan Zamanian and Ahmad Ahmadi Khalaji

Introduction The Urumieh-Dokhtar Magmatic Assemblage (UDMA) forms a distinct NW-SE linear intrusive–extrusive complex Magmatism of the UDMA that occurred from Eocene to Quaternary, although the maximum activity was in the middle Eocene (Berberian and King, 1981; Ghasemi and Talbot, 2006). Collision of Arabian and Iranian plates led to termination of Neo-Tethys crust subduction and magmatism activity was abated in the UDMA, although there is no common agreement on collision timing. The Takht magmatic complex is located in the north of the Hamedan province (west Iran), and it belongs to ‎the UDMA. The assemblage of volcano-plutonic rocks is present in the study area. The volcanic rocks include dacite, rhyodacite and trachyandesite with some tuff and agglomerated and the plutonic rocks are mostly occupied by granodiorite and diorite (containing mafic micro-granular enclaves) with some gabbro. These bodies are mostly intruded in Jurassic schists and are in contact with Cretaceous limestone leading to the formation of a skarn iron-ore deposit. The detailed geochemical and isotopic data is lacking and the age of the Takht granodiorite has not been determined. In the present study, the authors mainly have focused on the geochemistry and Sr-Nd isotopic ratios of the Takht magmatic complex to clarify questions regarding pterogenesis and its geodynamic evolution. We also reported U–Pb zircon ages for Takht granodiorite to study the relationship between its genesis and geological evolution history of the UDMA. Materials and methods A total of about 80 samples from the Takht plutonic-volcanic rocks were collected. 16 plutonic-volcanic samples were selected for whole-rock chemical analysis. Major element oxides were analyzed by the X-ray fluorescence spectrometry (XRF) method using an Optima 7300DV XRF instrument in the Lab West laboratory, Australia. Trace elements were also analyzed in this laboratory with the inductively-coupled plasma mass spectrometry (ICP-MS) method using a NeXION 300 ICPMS instrument. Three chip samples with equal weight (4.5 kg) were collected from the Takht granodiorite. Then upon mixing, average samples were obtained for U–Pb dating of zircon. Hand-picked zircon crystals were supplied to the ALC (Arizona Laser Chron Center) in Arizona University. The 14 selected samples for Nd-Sm and Rb-Sr isotope analysis were crushed to less than 60µm. All isotope analyses were performed on a Nu Instruments Nu Plasma HR in the MC-‎ICP-MS facility, in the University ‎of Cape Town, Rondebosch, South Africa. Results The plutonic rocks have metaluminous nature and are of calc-alkaline affinity. The Sr/Nd, Nb/La and Th/U ratios of the granodiorite show that its magma was formed mainly by melting of continental crust, and that its enclaves were formed from a mantle derived mafic magma. The samples have negative anomalies in Nb, Sr, Ti, P and Eu and positive anomalies in Th, K, Zr, Yb and Rb thus indicating contribution of mantle and crustal materials in their generation. The Takht granodiorite has geochemical features of I and A-type granites and also shows properties of both volcanic arc and within plate magmatism association granitoids (high levels of LILEs and HFSEs). In order to obtain better results, all the data were plotted on a common 206Pb/238U versus 207Pb/235U diagram. The results show an age of 16.8 ± 0.24 Ma (Middle Miocene) for the Takht granodiorite. Based on the results, the Takht granodiorite was generated in Miocene. In the Takht magmatic complex initial 87Sr/86Sr range from 0.70678 to 0.70778 and εNd also changes from -0.79398 to -5.83370. Nd-Sm isotopic contents and trace element ratios indicate that the Takht magmatic complex has originated from oceanic slab break-off with continental crust mingling in the post-collision stage. The εNd (16.8 Ma) vs. initial 87Sr/86Sr ratios diagram reveals, the role of continental crust materials in the generation of the granodiorite samples, while where the enclaves lie are plotted in the mantle evolution array field. Discussion The Takht magmatic complex has geochemical properties of arc related igneous rocks such as Ba, Nb, Sr, P, Ti and Y negative anomalies and for Rb, Th, U, K, Nd and Zr positive anomalies. Most of the Takht area samples are plotted in the triple junction of volcanic arc granites (VAG), within plate granites (WPG) and syn-collision (syn-COLG) on Y versus Nb and the Y+Nb versus Rb diagrams (Pearce et al., 1984). These data suggest post-collisional tectonic setting for the Takht magmatic complex. Field, microscopic and geochemical evidences indicate that simple fractional crystallization of a mafic magma was not the only processes involved in the generation of the studied rocks. On this basis, continental crust material had extensive contribution in the generation of the granodiorites whereas the enclaves are from mantle derived magmas. Relatively high fractionated REE patterns of the granodiorite samples with high LREE/HREE indicate an amphibole-bearing, garnet-free source for the samples while small to moderate negative Eu anomalies require residual plagioclase in the source. The granodiorite samples basically have geochemical properties of I-type granites and it is confirmed by their Nd and Sr isotopic ratios. However, relatively high HFSE contents make them similar to A-type granites. Melting of a former continental arc crust and contamination with mantle derived magmas led to both volcanic arc and within plate geochemical properties of the granodiorites that make them similar to I-type and A-type granitoids. The age of 16.8 ± 0.24 Ma (Middle Miocene) of the Takht granodiorite is consistent with the other post-collisional igneous rocks of the area and regarding its post-collisional geochemical properties the age of collision and related orogeny must be considered at least before Miocene. References Berberian, M. and King, G.C.P., 1981. Towards a paleogeography and tectonic evolution of Iran. Canadian Journal of Earth Science, 18(2): 210–265. Ghasemi, A. and Talbot, C.J., 2006. A new tectonic scenario for the Sanandaj–Sirjan Zone (Iran). Journal of Asian Earth Sciences, 26(6): 683–693. Pearce, J.A., 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.

561-586

Authors: Majid Heidari, Alireza Zarasvandi, Mohsen Rezaei, Johann Raith and Adel Saki

Introduction Almost all of the well-known porphyry copper deposits in Iran occur within the Kerman Cenozoic magmatic arc (KCMA) (Fig 1) in the southeastern part of Cenozoic Urumieh–Dokhtar magmatic belt (Hassanpour et al., 2015). The Miocene Chahfiruzeh porphyry copper deposit as an example of collisional porphyry intrusion is located in the Kerman Cenozoic magmatic arc (Fig 2) (Einali et al., 2014). In this research, we attempt to characterize the physicochemical attributes of parental magma in the Chahfiruzeh porphyry deposit, using chemistry of magmatic biotite. Materials and methods Samples from various rocks were collected from drill cores belonging to 123.1-667.1m depths. The chemical compositions of magmatic biotites were obtained by analyzing the carbon coated polished thin sections using electron probe microanalyzer (EPMA). All samples were prepared and analyzed in the Montanuniversität Leoben, Austria using a superprobe Jeol JXA 8200 instrument. The analyses were conducted with 15 kV accelerating voltage and 10 nA beam and beam size of about 1 μm. The counting times (upper and lower) were 100 and 20 s, respectively. Results Chahfirouzeh porphyry deposit containing 100 Mt ore reserves (Mohammaddoost et al., 2017), and 0.4-0.8% Cu is located at the 95 km NW of Sarcheshmeh deposit and 35 km NE of Shahr-e- Babak in the Kerman province. (Einali et al., 2014). The compositions of analysed magmatic biotites from the Chahfiruzeh porphyry copper deposit are summarized in Table 1. According to (Mg–Li) vs. (Fetot + Mg + Ti–AlVI) and Mg–(Fe2+ + Mn)–(AlVI + Fe3+ + Ti) diagrams, the biotite from Chahfiruzeh deposit are Mg-rich (Fig. 5-A,B). Chemical compositions of biotites on the ternary diagram of Beane (1974) shows a magmatic origin for the analysed samples (Fig 7). Magmatic biotites are characterized by high SiO2 values ranging from 37.44-44.71 (Wt. %). Also, MgO and FeO vary between 12.54-14.36 (Wt. %) and 14.94-16.3 (Wt.%), respectively. Moreover, TiO2, K2O, and Na2O range from 4.53-5.97, 8.3-9.38, 0.15-0.29 (Wt.%), respectively (Fig 6-A-D). Fluorine and Cl contents in biotite range from 0.3 to 1.52 wt.% and 0.03 to 0.04 wt.%, respectively. Discussion Chemical compositions of selected biotites on the classification diagrams of Abdel-Rahman (1994) indicate that magmatic biotites from the Chahfiruzeh porphyry copper deposit belong to calc-alkaline (C) series (Fig. 8). Also, according to ternary Xpdo-Xan-Xph diagram (Wones and Egster , 1965), Oxygen fugacities of Chhfiruzeh and other pre-collisional porphyry deposits (e.g., Reagan) occur in NNO distinct (Fig 9). It is evident that granitic rocks of both studied deposits are formed in relatively similar oxidiant conditions. Moreover, the preformed geothermometry on the magmatic biotites in the Chahfiruzeh porphyry the copper deposit shows a range of temperatures between 478-632 ° C (average 565.3 °C). Moreover, XMg/XFe values confirm that Mg is enriched in Chahfiruzeh (collisional porphyry) compared to that of Reagan (pre-collisional porphyry; Fig 10-A). Also, fluorine has the highest concentration in collisional porphyry copper deposits. The plot of the Chahfiruzeh biotites on the log (XMg/ XFe) versus log (XF/XOH) discrimination diagram of Brimhall and Crerar (1987) represent that the intrusion crystallized from a weakly to strongly crustal-contaminated, I-type granitic magma (Fig 11). The log fH2O/fHF and fH2O/fHCl ranges between 4.69-4.84 and 4.09-4.28 having an average value of 5.14 and 4.14, respectively (Table 1). According to XFe vs. XF/XOH and XCl/XOH, Cl fugacities in Chahfiruzeh are analogous to that of Reagan porphyry (Fig 12). The calculated halogen fugacity ratios (log fH2O/fHCl vs. log fH2O/fHF and fHF/fHCl) and log fH2O/fHCl vs. IV(Cl) of magma in equilibrium with biotite for Chahfiruzeh porphyry and comparison with Reagan and other known porphyry of the world show that Chafiruzeh and Ragan deposits are analogous to those of Sarcheshmeh and Bingham porphyry deposits (Fig 13 and 14). Finally, Chahfiruzeh deposit as collisional porphyry has higher IV(F) than Reagan deposit (pre-collisional). In comparison with collisional porphyry copper systems (Chahfiruzeh), poor mineralization in the Reagan pre-collisional deposit may be due to lower Cl content of the magma in Reagan deposit. Acknowledgements This research was made possible by the help of the office of vice-chancellor for Research and Technology, Shahid Chamran University of Ahvaz. We acknowledge their support. Authors highly appreciate the efforts of Prof. Johann. Raith and Dr. Federica Zaccarini for EMPA analysis. We also gratefully acknowledge the staff of the National Iranian Copper Industries Company (NICICO), for helping us in sampling. References Abdel-Rahman, A.M., 1994. Nature of biotites from alkaline, calc-alkaline, and peraluminous magmas. Journal of Petrology, 35 (2): 525–541. Beane, R.E., 1974. Biotite stability in the porphyry copper environment. Economic Geology, 69(1): 241–256. Brimhall, G.H. and Crerar, D.A., 1987. Ore fluids: magmatic to supergene. Reviews in Mineralogy and Geochemistry, 17(1): 235–321. Einali, M., Alirezaei, S. and Zaccarini, F., 2014. Chemistry of magmatic and alteration minerals in the Chahfiruzeh porphyry copper deposit, south Iran: implications for the evolution of the magmas and physicochemical conditions of the ore fluids. Turkish Journal of Earth Sciences, 23(1): 147–165. Hassanpour, Sh., Alirezaei, S., Selby, D. and Sergeev, S., 2015. SHRIMP zircon U–Pb and biotite and hornblende Ar–Ar geochronology of Sungun, Haftcheshmeh, Kighal, and Niaz porphyry Cu–Mo systems: evidence for an early Miocene porphyry-style mineralization in northwest Iran. International Journal of Earth Sciences, 104(1): 45–59. Mohammaddoost, H., Ghaderi, M., Kumar, T.V, Hassanzadeh, J. and Alirezaei, S., 2017. Holly J. Stein e,f, E.V.S.S.K. BabuZircon U–Pb and molybdenite Re–Os geochronology, with S isotopic composition of sulfides from the Chah-Firouzeh porphyry Cu deposit, Kerman Cenozoic arc, SE Iran. Ore Geology Reviews, 88 (1): 384–399. Wones, D.R. and Eugster, H.P., 1965. Stability of biotite: experiment, theory, and application. American Mineralogist, 50(1): 1228–1272.

617-636

Authors: Seyed Javad Moghaddasi, Ebrahim Tale Fazel and Aliyeh Sadat Banifatemi

Introduction Fluorite ore deposits are classified into three main groups: (1) magmatic deposits, (2) structures related deposits, and (3) sedimentary deposits (Dill, 2010). More than 30 fluorite occurrences with approximately 1.35 million tons of reserves have been recognized in Iran (Miller, 2014). Bagher Abad and Darreh Badam fluorite ore deposits, located in the southeast of Delijan (Markazi province) occur between the central Iran structural zone from the north and the Sanandaj-Sirjan structural zone from the south. The geology of the area is dominated by folded and faulted structures of Jurassic carbonates and shales (Thiele et al., 1968). The main host rocks for fluorite mineralization in the studied area are the Lower-Upper Jurassic carbonates and shales of Shemshak and Badamu Formations. Materials and Methods In this study, 70 samples from the various rock types including fluorite veins, host rocks and related alterations were collected. 25 thin- and polished thin-sections were prepared and studied to explain the mineralogy and paragenetic sequence of the ore body. Eight double-polished sections were also prepared for micro-thermometric analysis. The micro-thermometric analyses were conducted on primary fluid inclusions using Linkam THM600 heating-freezing stage connected to a TMS94 temperature controller and a liquid nitrogen pump (LNP) cooling system. Results The main host rocks for fluorite mineralization in the studied area are composed of the lower Jurassic slate and phyllite (Shemshak Formation) and the Middle to Upper Jurassic dolomitic limestone and calcareous sandstone (Badamu Formation). The main alterations associated with fluorite mineralization are sericitization, silicification and argillization. According to the fluid inclusions data, fluorite mineralization in Bagher Abad and Darreh Badam deposits were precipitated because of pressure reduction of ore bearing fluids and mixing of a primary moderate-salinity brine with less saline meteoric water. Estimation of trapping pressure-temperature of the mineralizing fluid in Bagher Abad fluorite deposit using the intersecting CO2 and H2O isochors for aqueous, aqueous-carbonic and carbonic fluid inclusions indicated that fluorite mineralization occurred at 180-260°C and 1-2 kbar pressure. According to the present study, circulation and upward flow of hydrothermal fluids (containing H2O and CO2) that originated from underlying altered bedrock provided appropriate conditions for increasing the solubility of metals and formation of halide (Cl¯ and F¯) metal complexes. Reaction with wallrock and gradual decrease in temperature due to mixing and dilution of the above-mentioned fluids with low-salinity meteoric water resulted in fluorite mineralization in favorable structures such as veins. Discussion Bagher Abad and Darreh Badam fluorite ore deposits are examples of epigenetic mineralizations which are not related to igneous activities in Iran. The mineralization is formed in nearly vertical veins, which are relevant to local fractures hosted in the Lower-Upper Jurassic carbonates and shales with east-west trend. The main ore textures are open-space fillings, breccias, veins and cavities associated with sericitic, silicic and argillic alterations. Micro-thermometric measurements were carried out on primary fluid inclusions in fluorite, calcite and barite minerals from both Bagher Abad and Darreh Badam deposits. Three types of fluid inclusions were distinguished: (1) two phase aqueous fluid inclusions (LV), (2) liquid (L) or vapor (V) mono phase inclusions, and (3) aqueous-carbonic (L1+L2+V) fluid inclusions. The first ice melting temperatures (Te) of two phase aqueous inclusions (LV) in fluorite, calcite and barite from Bagher Abad and Darreh Badam deposits vary between -32 to -15°C and -35 to -24°C, respectively, which represents a H2O+NaCl±KCl multiphase fluid (Van den Kerkhof and Hein, 2001). The last ice melting temperatures (Tmice) vary between -10.5 to -2.3°C and -12.0 to -5.6°C which are equal to salinities of 5.6-14.7 and 8.3-15.2 wt% NaCl equivalent for Bagher Abad and Darreh Badam deposits, respectively. The final homogenization temperatures (Thtotal) vary between 127 to 188 °C and 176 to 270°C for Bagher Abad and Darreh Badam deposits, respectively. The CO2 melting temperatures (TmCO2) of aqueous-carbonic inclusions in fluorite, calcite and barite show a range of -58.3 to -56.6°C which suggests CH4 and/or N2 impurities (Burruss, 1981). The clathrate melting temperatures (Tmclath) ranging from -6.0 to +1.0°C represent salinities between 5.5 to 18.2 wt% NaCl equivalent for both Bagher Abad and Darreh Badam fluorite deposits. References Burruss, R.C., 1981. Analysis of phase equilibria in C–O–H–S fluid inclusions. In: L.S. Hollister and M.L. Crawford (Editors), Fluid inclusions: applications to petrology. Mineralogical Association of Canada Short Course Series, Ontario, pp. 39–74. Dill, H.G., 2010. The chessboard classification scheme of mineral deposits: mineralogy and geology from aluminum to zirconium. Earth-Science Reviews, 100(1): 1–420. Miller, M.M., 2014. Fluorspar. In: S.M. Kimball (Editor), Mineral commodity summaries 2014. U.S. Geological Survey, Reston, Virginia, pp. 56–57. Thiele, O., Alavi, M., Assefi, R., Hushmand-zadeh, A., Seyed-Emami, K. and Zahedi, M., 1968. Explanatory text of the Golpaygan quadrangle map, scale 1:250,000. Geological Survey of Iran, Geological quadrangle E7, Tehran, 24 pp. Van den Kerkhof, A.M. and Hein, U.F., 2001. Fluid inclusion petrography. Lithos, 55(1–4): 27–47.

677-706

Authors: Mohammad Hassan Karimpour, Azadeh Malekzadeh Shafaroudi, Zahra Alaminia, Abbas Esmaeili Sevieri and Charles R. Stern

Introduction Mississippi Valley-Type (MVT) deposits are epigenetic zinc and lead deposits with minor copper hosted by dolostone, limestone, and locally sandstone in platform carbonate sequences inboard of major orogenic belts (Leach and Sangster, 1993; Leach et al., 2010). The Irankuh-Ahangaran Belt, which is the most important Pb-Zn mineralized zone of Iran, is situated within the Sanandaj-Sirjan tectonic zone. This belt is 400 km in length and 100 km in width. Three deposits including Irankuh mininig district, Ahangaran and Hosseinabad deposits were studied in this article (Fig. 1). The aim of this research is study of thermal gradient of subducted slab and age of formation of Pb-Zn deposits at Irankuh-Ahangaran belt, which is contrary information has been published so far on the type and their formation. Also, chemistry of ore-fluid in MVT deposits and impact of dolomitic and shale host rock on paragenesis, alteration, style, reserves and grade of deposits were discussed.These parameters will certainly be useful for exploration of the hidden MVT type deposits in the Irankou-Ahangan belt. Result and Discussion The Irankuh mineralization is hosted by Cretaceous dolostone and minor Jurassic shale rocks as epigenetic. The constructive thrust fault, which has been cut the Jurassic and Cretaceous host rocks, has played a major role in the rising of fluid and formation of mineralization. Mineralization is occurred as replacement and open space filling (fault breccia, veinlets and cavity of rock) in dolostone and breccia, veinlet and open space filling in shale host rock. The mineral assembelages are Fe-rich sphalerite, Fe- and Mn-rich dolomite, ankrite, galena, minor pyrite, bituminous, calcite ± quartz ± barite within carbonate host rocks, whereas quartz, pyrite, Fe-rich sphalerite, galena, minor chalcopyrite, low Fe-dolomite, bituminous, ± barite ± calcite are important primary minerals at clastic hos rocks (Karimpour et al., 2018). The Ahangaran deposit is very similar to Irankuh in host rock, alteration, paragenesis, and form of mineralization. Thrust fault has a constructive role for occurrence of mineralization and later destructive strike slip and normal faults have caused the displacement and destruction of mineralization. The Hosseinabad deposit is hosted by Jurassic shale, siltstone, and sandstone rocks as vein-veinlets, breccia and open space filling with structural control. Alteratin consists of silicification, chlorite, bituminous, and minor siderite, dolomite and ankerite similar to mineralization hosted by shale in Irankuh district. The mineral assemblages are galena, Fe-rich sphalerite, pyrite, chalcopyrite and minor phyrotite. Due to the lack of a proper dolostone unit in the Husseinabad deposit, mineralization is concentrated in particular areas with low-grade and low-reserves. Based on lithology, alteration, mineralization style, structural control by thrust faults, mineral paragenesis, and comparison with differnet types of Pb-Zn deposits, all deposits of Irankuh-Ahangaran belt are MVT-type. Deep-seated thrust faults formed during the early stages of subduction (~ 70 to 75 Ma), and played an important role in the upward migration of hydrothermal fluids from the basement to shallow depths. The geochronology of pyrite in Irankuh district based on Re-Os method indicate age of Irankuh Pb-Zn mineralization is 66.5 ± 1.6 Ma (Liu et al., 2019). Since the thrust faults have been cut the Jurassic to Upper Cretaceous rocks, and according to the absoulte age determined in Irankuh, the mineralization of this belt have been formed in the age range of 66 to 56 million years ago, mainly in the Paleocene (Fig. 15). Karimpour and Sadeghi (2018) suggested the hydrothermal fluid originated from the dehydration of a hot and young oceanic subducted slab, which liberated Pb, Zn, and other metals, and may have removed metals from rocks and organic material of the continental crust. More than 90% of all the water within the oceanic slab was released in the depth zone of the forearc region (depth of 30 to 50 km) (Karimpour and Sadeghi, 2018). In the depth zone, Mg-rich silicate minerals (such as antigorite, hornblende, chlorite, talc) have broken and the produced fluid is rich in Mg and Fe (Fig. 17). The ore-fluid of MVT deposits is Si-poor and Fe- and Mg- rich. Such fluid is mineralized on the hosts of the dolstone (Irankuh and Ahangaran) or Shale-Siltstone (Hossein Abad, and part of Irankuh and Ahangaran). There are significant differences in the type of paragenesis, alteration, shape, dimensions, reserves and grade in the deposits of this belt, which is controlled by the host rock type. Based on all lithological evidence, alteration, shape of mineralization, existence of thrust faults, mineral paragenesis and specific geological and geographic location, it can be used to exploration of the hidden MVT deposits in this belt. References Karimpour, M.H., Malekzadeh Shafaroudi, A., Esmaeili Sevieri, A., Shabani, S., Allaz, J.M. and Stern, C.R., 2018b. Geology, mineralization, mineral chemistry, and ore-fluid conditions of Irankuh Pb-Zn mining district, south of Isfahan. Journal of Economic Geology, 9(2): 267–294. (in Persian with English abstract) Karimpour, M.H. and Sadeghi, M., 2018. Dehydration of hot oceanic slab at depth 30–50 km: KEY to formation of Irankuh-Emarat Pb-Zn MVT belt, Central Iran. Journal of Geochemical Exploration, 194: 88–103. Leach, D.L. and Sangster, D., 1993. Mississippi Valley-type lead-zinc deposits. Geological Association of Canadian. Specific Paper, 40: 289–314. Leach, D.L, Taylor, R.D., Fey, D.L., Diehl, S.F. and Saltus, R.W., 2010. A Deposit Model for Mississippi Valley-Type Lead-Zinc Ores, Chapter A of Mineral Deposit Models for Resource Assessment. U.S. Geological Survey, Reston, Virginia, Scientific Investigations Report 2010–5070–A., 64 pp. Liu, Y., Song, Y., Fard, M., Zhou, L., Hou, Z. and Kendricke, M.A., 2019. Pyrite Re-Os age constraints on the Irankuh Zn-Pb deposit, Iran, and regional implications. Ore Geology Reviews, 104: 148–159.

1-23

Authors: Payam Roohbakhsh, Mohammad Hassan Karimpour and Azadeh Malekzadeh Shafaroudi

Introduction Kuh Zar Au-Cu deposit is located in the central part of the Torud-Chah Shirin Volcanic-Plutonic Belt, 100 km southeast of the city of Damghan. Mineralization including quartz-base metal veins are common throughout this Cenozoic volcano-plutonic belt (Liaghat et al., 2008; Mehrabi and Ghasemi Siani, 2010). The major part of the study area is covered with Cenozoic pyroclastic and volcanic rocks that are intruded by subvolcanic rocks. This paper aims to study the geological, geochemical and petrogenesis of the area using exploration keys for new mineral deposits in the Torud-Chah Shirin zone. Materials and methods To better understand the geological units and identify the alteration zones of the area, 200 rock samples were collected from the field and 132 thin sections with 15 polished thin sections were prepared for petrography and mineralization studies. Ten samples of intrusions with the least alteration were analyzed using the XRF at the East Amethyst Laboratory in Mashhad, Iran. These samples were also analyzed for trace and rare earth elements using ICP-MS, following a lithium metaborate/tetraborate fusion in the Acme Analytical Laboratories Ltd, Vancouver, Canada. 137 geochemistry samples were prepared by the chip composite method of alteration and mineralization zones and were analyzed in the Acme laboratory by Aqua Regia AQ250. Results The geology of the area consists of pyroclastic (crystal tuff) and volcanic rocks with andesite and latite composition, which were intruded by subvolcanic intrusive rocks with porphyritic texture and monzonitic composition. Monzonite rocks were intruded by younger subvolcanic units with dioritic composition. The intrusion of monzonitic pluton and stocks led to the formation of QSP, propylitic, carbonate and silicification-tourmaline broad alteration zones in the area. Monzonite rocks accompanied with disseminated mineralization of about 1 to 10% of pyrite and these sulfides have been converted to secondary iron oxides such as goethite, hematite and limonite. Lithogeochemical exploration revealed Au (up to 598 ppb), Ag (up to 3747 ppb), Cu (up to 679 ppm), Pb (up to 1427 ppm) and Zn (up to 1013 ppm) anomalies. Based on geochemical studies, intrusive rocks have characteristics of high-K Calc-alkaline to slightly shoshonitic and they are within metaluminous to the slightly peraluminous range. Enrichment of LREE versus HREE, enrichment of LILE and depletion in HFSE indicate that the magma was formed in the subduction zones. The negative Eu anomaly is due to the presence of plagioclase as a residual mineral in the magma source. The parent magma is probably formed by the partial melting of amphibolites. The presence of monzonite porphyry source rock, QSP and propylitic alterations, pyrite disseminated mineralization and geochemical anomalies of Au and Cu in the Kuh Zar deposit represents Au-Cu porphyry mineralization in the area. Discussion Tectonic setting discrimination diagrams (Pearce et al., 1984) show that subvolcanic rocks plot almost on the fields of the volcanic arc granites (VAG). In the Rb/Zr vs. Nb diagram from (Brown et al., 1984), the samples are plotted in the field of primitive island arc/continental margin arc. The Torud-Chah Shirin Belt is a part of the Alborz magmatic assemblage (AMA). The AMA has been interpreted to represent the subduction of the Neo Tethyan oceanic lithosphere beneath the Central Iranian continental microplate and the subsequent continental collision of the Arabian and Iranian microplates in the late Cretaceous-early Cenozoic (Berberian and Berberian, 1981; Berberian et al., 1982; Alavi, 1994; Golonka, 2004). Acknowledgement This study has been supported by the Research Foundation of the Ferdowsi University of Mashhad, Iran (Project No. 27126.3). The authors would like to acknowledge the East Amethyst Laboratory for XRF analysis. We also thank the Gold Company of Iran for providing conditions for camping and accommodation. References Alavi, M., 1994 .Tectonics of the Zagros orogenic belt of Iran: new data and Interpretations. Tectonophysics, 22(1): 211–238. Berberian, F. and Berberian, M., 1981. Tectono-plutonic episodes in Iran. In: F.M. Delany and H.K. Gupta (Editors), Zagros Hindukosh. Himalaya Geodynamic Evolution. American Geophysical Union, Washington DC, pp. 5–32. Berberian, F., Muir, I.D., Pankhurst, R.J. and Berberian, M., 1982 .Late Cretaceous and early Miocene Andean type plutonic activity in northern Makran and central Iran. Journal of the Geological Society, 139(5): 605–614. Brown, G.C., Thorpe, R.S. and Webb, P.C., 1984. The geochemical characteristics of granitoids in contrasting arcs and comments on magma sources. Journal of Geological Society, 141(3): 413–426. Golonka, J., 2004. Plate tectonic evolution of the southern margin of Eurasia in the Mesozoic and Cenozoic. Tectonophysics, 381(1-4): 235–273. Liaghat, S., sheykhi, V. and Najjaran, M., 2008. Petrology, gheochemistry and genesis of Baghu turquoise, Damghan. Journal of Science, University of Tehran, 34(2): 133–142. (in Persian with English abstract) Mehrabi, B. and Ghasemi Siani, M., 2010. Mineralogy and economic geology of Cheshmeh Hafez polymetallic deposit, Semnan province, Iran. Journal of Economic Geology, 2(1): 1–20. (in Persian with English abstract) Pearce, J.A., Haris, 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.

47-59

Authors: Mehrdad Barati, Akram Ostadhosseini, Iraj Rasa and Mohammad Yazdi

Introduction Using stream sediment geochemical exploration has been considered as a useful approach to explore the good potentials for many years. Problems might come up in the course of implementing resolving which may requires the use of more recent findings or auxiliary methods. One of the areas which has faced special problems during the conducting geochemical exploration is the Orzooiyeh region on the border of Kerman and Hormozgan provinces. Stream sediment exploration was carried out in the area in the scale of 1: 100,000. This region includes two different geological zones that are the Sanandaj-Sirjan in the northern part and the Zagros in the southern part. During the statistical analysis and method of eliminating the effects of the upstream rock it was determined that most of the element of chromium’s anomalies are in compliance with the Bakhtiari and Aghajari units which are lacking in the economic importance in the chromium ore. Current geochemical exploration methods often extract the anomalies based on classical statistical methods (Yazdi, 2002). In these methods, the range of the anomaly is just determined based on simple numerical calculations and except for grade, any of the other parameters do not have a significant role in determining the anomaly areas. However, procedures such as fuzzy logic, neural system, regression and hierarchical analysis process enable the users to involve more parameters in data processing (Oh and Lee, 2010; Kumar and Hassan, 2013; Carranza, 2008). For instance, using special algorithms has made parameters such as lithology and tectonic, geophysics and geochemistry effective in processing and determining the anomaly zones, and ranking each of the affective parameters in the anomaly based on their importance, and eventually achieving the maps and valuable anomaly areas possible (Bonham-carter, 1994; Carranza, 2008). This study was conducted to identify the significant anomalies zones using AHP and GIS techniques. Materials and methods AHP (Analytical Hierarchy Process) is the most comprehensive system designed for multi-criteria decision-making. This method was offered firstly by Sati in 1980, and has carried out numerous applications in different sciences until now. This technique also shows the consistency and inconsistency of the decision that is the outstanding benefit of this technique in multi-criteria decision-making and has been proposed for complex and fuzzy problems based on human brain analysis, and consists of three stages: basic, involving the creation of a hierarchy, determining priorities and logical consistency (Macharis et al., 2004). In AHP, the factors are compared with each other in pairs and the highest weight is given to the layer that makes the maximum impact on determining the goal (Carranza, 2008). So in this research, after the detection of the effective factors in determining the anomaly areas in the study area, the factors have been weighed for prioritizing the criteria in their order of importance and the paired comparison matrix is formed based on the characteristics of the area and comparative studies for criteria and sub-criteria. After the formation of paired comparison matrices using approximate arithmetic average, the relative weight of parameters was calculated. Then, the researcher carried out the various stages of preparing and the extracting data layer deals with each of these factors in the GIS environment and finally the layers were integrated with each other and the entire range of the anomaly was ranked based on appropriate models. Results The results of calculating the final weight criteria show that among the study groups, groups Geochemistry .0.45, lithology 0.45 and tectonic 0.1, respectively, are more significant. The ratio of consistency between these groups is 0.02 and is acceptable and the map prepared by the integration of these groups in the GIS environment according to calculated weights shows that a significant proportion of the false anomalies in the region have been eliminated, and the chromium anomalies associated with ophiolites and peridotites of the region show their best. Therefore, this method can be used for providing the mineral prospecting map that the abandoned mines located in the upstream of anomaly areas confirmed the efficiency of this method in the determination of the anomaly areas. Discussion In the present study, the hierarchical process analysis method was utilized to eliminate the false anomalies caused by small and non-significant placer deposits related to the detrital formations in the region. The effective factors in determining the anomaly zones were determined and the final map was constructed by integrating groups, lithology, elemental geochemistry and tectonics that is, the anomaly zones map was drawn in the GIS environment. The results show that the region anomalies are related to ophiolite and ultrabasic and a little bit the region detrital. Therefore, a significant percentage of false anomalies associated with the regional detrital of the area was eliminated by this method and the real anomalies showed their best. This discussion indicates the efficacy of the method of AHP and GIS technique, and they can be considered to be effective methods to reduce the impact of Singenetic factors and naturally to eliminate false anomalies. References Bonham-Carter, G.F., 1994. Geographic Information Systems for Geoscientists: Mod-eling with GIS. Pergamon Press, Oxford, UK, 398 pp. Carranza, E.J.M., 2008. Geochemical anomaly and mineral prospectivity mapping in GIS. Elsevier, Amsterdam, Netherlands, 368 pp. Kumar, S. and Hassan, M., 2013. Selection of a Landfill Site for Solid Waste Management: An Application of AHP and Spatial Analyst Tool. Journal of the Indian Society of Remote Sensing, 41(1): 45–56. Macharis, C., Springael, J., Brucker, K.D. and Verbeke, A., 2004. PROMETHEE and AHP: the design of operational synergies in multicriteria analysis. Strengthening PROMETHEE with ideas of AHP. European Journal of Operational Research, 153(2): 307–317. Oh, H.J. and Lee, S., 2010. Application of Artificial Neural Network for Gold–Silver Deposits Potential Mapping: A Case Study of Korea. Nonrenewable Resource, 19(2): 103–124. Yazdi, M., 2002. Conventional methods in geochemical exploration. Shahid Beheshti University, Tehran, 180 pp. (in Persian)

77-93

Authors: Amir Salimi, Mansour Ziaii, Ali Amiri and Mahdieh Hosseinjani Zadeh

Introduction In the regional prospecting of ore minerals, geologists usually utilize remote sensing images for hydrothermal alteration mineral mapping as a kind of lithological anomaly, which may be linked to mineral deposits (Carranza, 2002). Compared to the multispectral remote sensing images, composed of few spectral bands, the hyperspectral data prepare much more spectral details of the surface materials in many bands. These high spectral resolution images provide subtle spectral data for identifying similar materials of the surface (Camps-Valls et al., 2014). This ability could greatly promote the potential of hyperspectral based mineral mapping (Wang and Zheng, 2010). As in the two last decades, hyperspectral remote sensing has been an important tool for studying earth’s minerals and rocks (Zhang and Peijun, 2014). Although, the high number of spectral bands is an important advantage for hyperspectral images, many of those bands are usually irrelevant and redundant and, therefore, cause just the size and complexity of the band space to be increased. This complexity can lead to an ill-posed problem in supervised classification, namely the curse of dimensionality and the Hughes phenomenon, which negatively affect the accuracy of the classification (Camps-Valls, 2014). Feature reduction methods can be applied to overcome these problems and to eliminate those spectral bands in the classification of hyperspectral images that provide no further useful information. These methods produce an efficient subset of features (spectral bands in remote sensing field) from the original feature space. The decrease in complexity obtained as a result of the feature space reduction can increase the ability of classifiers to efficiently capture the classification rules. Consequently, the speed, generalization, and predictive classification accuracy are increased (Gheyas and Smith, 2010; Camps-Valls et al., 2014). This study is aimed at evaluation and management of the curse of dimensionality risk in hyper spectral data classification by means of a feature reduction method. The method is utilized to select more informative spectral bands of Hyperion hyperspectral data, which are more effective for the classification of hydrothermal alteration zones. The well-known study area here is the Darrehzar porphyry copper mine located 8 km from the southeast of the giant Sarcheshmeh mine. Materials and methods 1. Hyperion data The Hyperion hyperspectral image with 242 spectral bands acquired on July 26, 2004 was available and it was used in this study. 2. Train and test datasets Two datasets were utilized. The first dataset that resulted from the Mixture Tuned Matched Filtering (MTMF) method was applied to feed the feature reduction method and the second dataset containing 17 rock samples collected from the study area was used to carry out the classification by SVM. 3. The feature reduction method In this study, we applied a hybrid Feature Subset Selection (FSS) method to reduce the number of spectral bands of Hyperion data. Extensive details may be found in Moradkhani et al. (2015). Discussion and results The Feature Subset Selection (FSS) algorithm was applied to reduce the size of the spectral bands of Hyperion data. The implementation of this algorithm resulted in the selection of 9 bands among all 165 spectral bands (i.e. 5% of all useable spectral bands of Hyperion) as the more influential bands for the identification of clay minerals. These bands belong to the two spectral ranges, 2125-2250 nm and 2250-2400 nm, respectively. On the other hand, it is believed that the Short-Wave Infrared (SWIR) electromagnetic range (2000-2500 nm) is an important spectral range for distinguishing clay minerals of the hydrothermal alteration systems (Hosseinjani Zadeh et al., 2014). This implies that two ranges introduced by FSS were accurately selected, because both of them coincide with the SWIR range. Clearly speaking, bands 201, 202, 204, and 205 in the range of 2125-2250 nm are used for muskovit, kaolinit and alunit enhancement. Moreover, bands 217, 220, 222, 223, and 224 in the 2250-2400 nm are appropriate for chlorite classification. A comparison between the maps of SVM based classification of the alteration zones using 9 (selected by feature selection method) and 165 (all useable bands of Hyperion data) spectral bands confirmed a significant improvement in the output results when 9 more informative bands are utilized for classification instead of all 165 bands. In fact, the classification based on 9 selected bands is comparable and even more effective than the full band classification. This is because the decrease in spectral bands makes SVM learn the rules of classification more accurately. Reference Camps-Valls, G., Tuia, D., Bruzzone, L. and Benediktsson, J., 2014. Advances in Hyperspectral Image Classification. IEEE Signal Processing Magazine, 31(1): 45–54. Carranza, E.J.M., 2002. Geologically-Constrained Mineral Potential Mapping. Ph.D. Thesis, Delft University of Technology, Delft, Netherlands, 480 pp. Gheyas, A. and Smith, L.S., 2010. Feature subset selection in large dimensionality domains. Pattern Recognition, 43(1): 5-13. Hosseinjani Zadeh, M., Tangestani, M.H., Velasco Roldan, F. and Yusta. I., 2014. Spectral characteristics of minerals in alteration zones associated with porphyry copper deposits in the middle part of Kerman copper belt, SE Iran., SE Iran. Ore Geology Reviews, 62: 191-198. Moradkhani, M., Amiri, A., Javaherian, M. and Safari, H., 2015. A hybrid algorithm for feature subset selection in high-dimensional data sets using FICA and IWSSr algorithm. Applied Soft Computing, 35: 123–135. Wang, Z.H. and Zheng, C.Y., 2010. Rocks/Minerals Information Extraction from EO-1 Hyperion Data Base on SVM. International Conference on Intelligent Computation Technology and Automation, Changsha, China. Zhang, X. and Peijun, L., 2014. Lithological mapping from hyperspectral data by improved use of spectral angle mapper. International Journal of Applied Earth Observation and Geoinformation, 31: 95–109.

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Authors: Abbas Etemadi, Mohammad Hassan Karimpour and Azadeh Malekzadeh Shafaroudi

Introduction The Hamech prospect area is located in the eastern Iran, 85 kilometers southwest of Birjand. The study area coordinates between 58¬¬˚¬53΄¬00 ˝ to 59˚¬00΄¬00˝ latitude and 32˚¬22΄¬30 ˝ to 32˚¬26΄¬00˝ longitude. Due to the high volume of magmatism and the presence of geo-structure special condition in the Lut Block at a different time, a variety of metal (copper, lead, zinc, gold, etc.) and non-metallic mineralization has been formed (Karimpour et al., 2012). The studied area (Hamech) includes Paleocene-Eocene igneous outcrops which contain a wide range of subvolcanic bodies (diorite to monzonite porphyry) associated with mafic intrusives, volcanic units (andesite), volcaniclastic and sedimentary rocks. Material and Methods This study was done in two parts including field and laboratory works. Sampling and structural studies were done during field work. Geological and alteration maps for the study area were also prepared. 200 thin and 60 polished sections for petrographic purpose were studied. The number of 200 thin sections and 60 polished sections were prepared and studied in order to investigate petrography and mineralogy. Major oxides (XRF method- East Amethyst Laboratory in Mashhad), rare earth elements and trace (ICP-MS method-ACME Laboratory in Vancouver, Canada) elements were analyzed for 13 samples that included subvolcanic units and intrusive bodies. Data processing and geological and alteration mapping is done by the GCD.kit and Arcgis software. Discussion and Results Based on lab work and XRF analysis, the rocks in the area are composed of intrusive-subvolcanic bodies and volcanic rocks (andesite, trachyandesite and dacite) together with volcano-classic and sedimentary rocks. Also, alteration zones consist of a variety of argillic, silicified, quartz-sericite-pyrite (QSP), propylitic and carbonate. Igneous rock textures are mainly porphyritic for sub-volcanic and granular for intrusive bodies. Phenocrysts mainly consist of plagioclase and hornblende dominated with minor of biotite and pyroxene. XRF studies and output charts show that rocks include monzonite, diorite, gabbro and gabbroic diorite. Intermediate subvolcanic units (monzonite, diorite) and mafic intrusives (gabbro and gabbroic-diorite) are related to high-potassium calc-alkaline (K2O between 2.42 to 4%) and tholeiitic (K2O between 0.15 to 0.27%) series, respectively. Subvolcanic units belong to the I-type granitoid (Chappell and White, 2001). Mantle normalized , trace-element spider diagrams display enrichment in LREE, such as Rb, Sr, K, and Cs, and depletion in HREE, e.g., Nb, Ti, Zr that indicate magma formed in the subduction zone. Nb depletion (less than 6 ppm, between 0.5 to 5.2 ppm) in subvolcanic bodies represents a volcanic arc granitoids (VAG) tectonic setting that is related to the subduction zone (Pearce et al., 1984). Also, this reduction shows that these rocks are derived of oceanic crust (Wilson, 1989). Enrichment in LREE and depletion of HREE with a low (La/Yb)N ratio in the Hamech subvolcanic rocks (6/85 to 8/13) could represent a low degree of mantle partial melting (Wass and Rogers, 1980). Zr/Nb ratio of more than 10 for Hamech rocks (between 21 and 35 for intermediate subvolcanic and 67 to 72 for mafic bodies) indicates that parental magma has minimal crustal contamination (Karimpour et al., 2012). Sr enrichment (between 646 to 1124) and low negative Eu anomaly (Eu/Eu* ratio between 0.81 to 1/02) show that plagioclase is rare (or is not present) as residue mineral in the source and melt conditions have been in oxidation state (Tepper et al., 1993). Based on Sm/Yb vs. La/Sm (Shaw, 1970) and Ce/Yb vs. Sm/Yb (Wang et al., 2002) diagrams, parent magma is composed of 1 to 5% spinel-garnet lherzolite partial melting (with small amounts of garnet) at a depth between 65 to 67 km (upper mantle) for subvolcanic units and 5 to 20% spinel lherzolite partial melting (depletion mantle-NMORB) with a depth of less than 55 km for mafic bodies. Suitable tectonic setting, existence of subvolcanic units with intermediate composition, magnetic activity with the nature of calc-alkaline and oxidants, data from major and REE studies, mineralization as disseminated and veinlets with high secondary iron oxides in surface show suitable conditions of porphyry and epithermal mineralization in the Hamech prospect area. References Chappell, B.W. and White, A.J.R., 2001. Two contrasting granite types, 25years later. Australian Journal of Earth Sdiences, 48(4): 489–500. Karimpour, M.H., Malekzadeh Shafaroudi, A., Farmer, L. and Stern, C.R., 2012. Petrogenesis of Granitoids, U-Pb zircon geochronology, Sr-Nd Petrogenesis of granitoids, U-Pb zircon geochronology, Sr-Nd isotopic characteristics, and important occurrence of Tertiary mineralization within the Lut block, eastern Iran. Journal of Economic Geology, 4(1): 1–27. (in Persian with English abstract) Pearce, J.A., Harris, N.W. and Tindle, A.G., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology, 25(4): 956–983. Shaw, D.M., 1970. Trace element fractionation during anataxis. Geochimica et Cosmochimica Acta, 34(2): 237–243. Tepper, J.H., Nelson, B.K., Bergantz, G.W. and Irving, A.J., 1993. Petrology of the Chilliwack batholith, North Cascades, Washington: generation of calc-alkalinegranitoids by melting of mafic lower crust with variable water fugacity. Contributions to Mineralogy and Petrology, 113(3): 333–351. Wang, K., Plank, T., Walker, J.D. and Smith, E.I., 2002. A mantle melting profile across the Basin and Range, SW USA. Journal of Geophysical Research: Solid Earth, 107(B1): 5–21. Wass, S.Y. and Rogers, N.W., 1980. Mantle metasomatism- precursor to alkaline continental volcanism. Geochimica et Cosmochimica Acta, 44(11): 1811–1823. Wilson, M., 1989. Igneous Petrogenesis. Chapman and Hall, London, 466 pp.

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Authors: Mohammad Reza Hezareh

Introduction The Urmia-Naqadeh-Mahabad basin is a part of the south and west Urmia Lake drainage basin that covers some parts of East-and-West Azerbaijan and northern Kurdistan. This study is the integration of geological, hydrological, remote sensing, geochemical and airborne geophysical data classifying promising areas that are related to sandstone type uranium (U) mineralization in Iran. Based on positive factors such as favorable source, host rocks and suitable hydrological pattern, this basin is a favorable basin in Iran. According to the characteristics of lithology, tectonic, sedimentary environment, geotectonics and etc. the basin could be classified into favorable, promising and possible subbasins for mineralization of U sandstone type. Material and methods Geological data show that this region is a part of the Sanandaj-Sirjan zone and consists of Precambrian metamorphic rocks which are covered by younger sedimentary and volcano-sedimentary rocks that are influenced by different metamorphic phases. More than 7597 stream sediment samples from the area have been analyzed for Se،V، Mo، As،Cu، Ag، Zn، Co، Ni، Pb، Ti، Th، Zr، P and Sn. The basin is divided into 11 individual sub-basins. Radiometric data of the basin have been acquisitioned during 1976-1978 by an Australian-German- French Company with line separation of 500 meters and 120 meters of nominal terrain clearance. Remote sensing data reveals that the western subbasin is suitable for sandstone type uranium mineralization. Based on geochemical evidences, the Au, Zn, Sn, As and Pb elements were enriched. Geophysical investigation reveals that the Eastern basin includes high amounts of U and low amounts of Th. Hydrogeological study demonstrates that the trend of groundwater is from the west to the east. Geochemical data revealed that we can divide the basin into 11 subbasins which are characterized as follows: 1. Ghara Aghaj (126 Km2), North to south trend is situated at the northern part of the basin. At this basin Ni, Co, Cu and V are reported but it is not related to mineralization. 2. Ghoma – Bezrgah (36 Km2). The East to the West trend is situated at the western part of the basin. At this basin Pb, As, Sn, Zn and Au are reported which can be related to skarn mineralization. 3. Piram – Shilan (342 Km2). At this basin Pb, Zn, As and Mo are reported which contain source rocks of uranium mineralization but there is no evidence of host rock and mineralization. 4. Pirestan1 (28 Km2). According to geological data a granitic body which can be the source of uranium mineralization and cretaceous volcanic rock outcropped. The fault system is weak by the north to the south trend. The anomalies of Pb, Mo, As and Sn are reported but there is no evidence of mineralization. 5. Kooh-e sabz poosh (34 Km2). Based on geological data half of the area is covered by granodioritic body which can be the source of uranium mineralization. The fault system has two trends (NE-SW and N-S). The anomalies of V, As, Mo and Co are reported but there is no evidence of mineralization. 6. Pirestan2 ((83 Km2). According to geological data a granitic and granodioritic body can be the source of uranium mineralization. The anomalies of Mo, Sn, Co, As and Zn are reported but there is no evidence of mineralization. 7. Chahar Taq (36 Km2). The fault system has the NE to SW trend and trusted mechanism. The anomalies of Zn, Ni and Au are reported but there is no evidence of mineralization. 8. Zaveh Kooh (111 Km2). The rock units have the NW to SE trend according to the Sanadaj-Sirjan trend. The anomalies of Pb, As, Sn, Mo, Ti, Cu, Ni and Au are reported but there is no evidence of uranium mineralization but there is some evidence of orogenic gold mineralization. 9. Saqqez-Baneh (465 Km2). The rock units have the NW to SE trend according to the Sanadaj-Sirjan trend. The anomalies of Co, Ti, Cu, Zn, Pb, Ni, Mo, Sn, Ag, Au and As are reported but there is no evidence of uranium mineralization and the same as the 8th subbasin there are known deposits of orogenic gold mineralization. 10. Charkeh (104 Km2). The rock units have the NW to SE trend. The anomalies of Zn, Mo, Sn, V, Ni, Au, As and Pb are reported but there is no evidence of mineralization. 11. Sheikh Ebrahim (38 Km2). The anomalies of Mo, Au, As and Pb are reported. The integration of the different layers shows that the prospecting area is suitable for future exploration of blind deposits. Geophysical data was processed and revealed those areas which have data. They can be classified into 5 different classes based on U and Th concentrations. The Hydrogeological data consist of EC, pH, Eh, DO and salinity. And the temperature was measured at the field by Sension 156 multimeter and was sent for ICP-MS analysis to the AMDEL and Applied Geological Research Center (Karaj) laboratories. Two samples were obtained from each well by Widel et al.’s (1998) method. One sample was analyzed for Ca2+، Mg2+، Na+، K+، CO32-، HCO3-، SO42-and Cl- and the other samples were analyzed for major and trace elements. At each basin charge, the discharge and the trend of underground water were defined. Results The results revealed that this basin contains alkaline magmatic rocks such as alkaline rhyolite and tuff which are situated in reduced shale and continental volcanic clastic rocks and can be the source of uranium at the study area. Besides these rocks, tuffaceous sandstone, metamorphose sandstone and young alluvial by the reduction condition can be the suitable hosts for mineralization. Based on geological, geochemical, hydrogeological and geophysical data, the western basin is suitable for sandstone type uranium deposit and also there is some evidence of mineralization.

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Authors: Saeed Abbaszadeh, Bijan Maleki, Seyed Reza Mehrnia and Saeedeh Senemari

Introduction Complete recognition of exploration criteria is considered as an important step in the systematic and scientific analysis of mineral potential mapping. The starting point of this analysis is recognition of the mineral potentials and the mechanism of their formation in different geological areas. In order to achieve such goals we can benefit from the known mineralization information. Integrating and analyzing all the data in the geographic information systems (GIS) can lead to the identification of promising mineral areas for future studies (San Soleimani et al., 2011). GIS can be used to organize, process, analyze and integrate the results of geological, geochemical and geophysical, tectonic and alteration studies in order to identify and evaluate the potential of different minerals (Bonham Carter, 1998). The aim of this paper is to apply the fuzzy integration method in GIS with using all the information, without the need to simplify them, in less time and with acceptable accuracy in order to recognize mineral potentials in the Ramand region. Investigation of mineral potentials in this area with using fuzzy logic in addition to the scientific-research aspects, can provide the discovery of appropriate patterns for other mineral resources in Iran. Materials and method The first step in any exploration project is that mapping is done with the aim of optimal potential to provide a model for the exploration of possible deposits in the region. This process in next steps will be continued with an extraction of useful information from various data that are contained in the database and this done work is done based on the properties of the elements under prospecting and the relevant exploration models. However, in the final stage, the combination of these maps is based on different models (Bonham Carter, 1998). The pre-requisite for the production of the mineral potential map, is to determine the weight and value which reflects the relative importance of the data classification (Hosseinali and Alesheikh, 2008). According to the study's default that is modeling with using fuzzy logic, a range of values between zero and one can be used to express the degree or the value of a collection (Novriadi and Darijanto, 2006) This is such that zero means lack of full membership and value of one is meant to be a full member of the collection. So, other set members can also be allocated values between zero and one and based on the degree of their membership to the set. So, it can be said that in the mining exploration, membership values are used to indicate the relative importance of each map as well as the relative importance of each class of a single map (Bonham Carter, 1998). Exploratory layers produced in GIS (in the fuzzy theory section), appear in the role of fuzzy sets and are combined by fuzzy operators (Table 1). The combining layers in the fuzzy method express the concept from the optimal options. Discussion In this study, some of the geo-referenced data consisting of geological data, remote sensing, tectonic and geophysical data have been used. Geological data for separate lithological units in the region and the identification of faults, remote sensing data to identify hydrothermal alterations and fault lineaments and airborne geophysical data in order to detect magnetic fault lineaments and check the changes of magnetic susceptibility related to hydrothermal alterations are used so that after collecting and entering data, processing the necessary studies has been carried out on them. Finally, by combining the results of each layer and giving the fuzzy weighting to them based on their importance in mineralization and the use of the fuzzy algorithm and gamma (the fuzzy operator) in GIS, the final map is obtained to identify the potential areas with using it in the Ramand region. The possibility to acquire the exploration pattern of base and precious metals is provided in the mineral-prone areas. Results In this study, there was a lot of exploration of information such that the decision to determine the potential points and continuing the exploration activities had been made very difficult. Thus, with use of the fuzzy integration method in GIS, all of the information were managed without any need to simplify them, in less time and with acceptable accuracy. Fuzzy logic is a method based on expert knowledge that is used for integration of exploration data and producing the optimal potential map of the Ramand regional reserves. It points to promising and priority areas for accurate and detailed information. Therefore, it is better to carry out exploration operations and reduces the cost and time as well as expedition to decision-making. And accuracy is very effective. References Bonham Carter, G.F., 1998. Geographic information systems for geoscientists: modeling with GIS. Pergamon Press, Oxford, 398 pp. Hosseinali, F. and Alesheikh, A.A., 2008. Weighting Spatial Information in GIS for Copper Mining Exploration. American Journal of Applied Sciences, 5(9):1187–1198. Novriadi, H.P.M. and Darijanto, T., 2006. Applying Fuzzy Logic Method in Mineral Potential Mapping for Epithermal Gold Mineralization in the Island of Flores, East Nosa Tenggara Using Geographical Information Systems (GIS). Proceeding of 9th International Symposium on Mineral Exploration, Institut Teknologi Bandung, Bandung, Indonesia. San soleimani, A., Asadi Haroni, H., Tabatabaei, S.H. and Samari, H., 2011. Mineral potential mapping at 1:10000 scale geological map of Kahak using Fuzzy Logic method. 5th National Conference of Geology and Environment, Islamic Azad University, Eslamshahr, Iran. (in Persian with English abstract)

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Authors: Seyedeh Narges Sadati, Mohammad Yazdi and Zahra Nourian Ramsheh

Introduction The Tabriz basin is an intra-mountain basin (Reichenbacher et al., 2011), which includes the Qom Red Bed Formation along with the Miocene Upper Red Formation. The lower unit of the Upper Red formation, M2mg unit, which hosts copper deposits includes an alternation of green grey sandstone and red marl with the interlayer of gypsiferous and saltiferous sediments (Sadati et al., 2013). Based on paleontological evidence, this unit is middle Miocene in age and is overlain by red sandstone, marl, shale (M3ms, M4sm) and locally up to red conglomerate (M5sc). In addition, this unit has considerable evaporitic layers, such as gypsum and salt. On the basis of field study all mineralization is distributed in the light-colored layers of the red sedimentary sequence, especially at the boundary between a red layer and a light-colored layer and is mostly restricted to within palaeo channels which consist of greenish-grey, well-sorted coarse- to very coarse-grained sandstones to microconglomerates. Both pyrite and copper-bearing minerals usually occur in the stratification of the organic matter- bearing host rocks which are mainly composed of gray sandstone. The size of organic matter varies from a few millimeters to 5-10 cm in length; almost all fragments are flattened and oriented conformably to bedding planes of host sedimentary rocks. Also, fine-grained sulfides are disseminated along the bedding planes in the sandstone. Copper precipitation in these places was possibly promoted by reduction from such organic materials. Sampling and analytical methods Investigations on mineralized samples showed that pyrite is the first sulfide mineral precipitated in the selected samples, followed by chalcopyrite, bornite, chalcocite, digenit, and covellite. The intergrown nature of sulphur-bearing minerals, along with their small grain size and their inter locking with detrital grains and calcite cement, make physical separation extremely difficult, although microdrilling techniques can achieve spatial resolutions for these samples. In the laboratory 25 to 100 µg (weight depends on the mineral analyzed) of the samples derived from microdrilling was combusted in a Eurovector 3000 elemental analyzer, yielding sulfur dioxide that was delivered to an Isoprime mass spectrometer using continuous-flow techniques, with helium as the carrier gas. Also, sulfide mineral powder was analyzed for the sulfur isotope compositions. Some samples were crushed to 40 to 60 meshes and the sulfide mineral separates were handpicked under a binocular microscope. The sulfur isotopes were analyzed at the Stable Isotope Laboratory, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing. The isotopic data are reported using the δ notation in units of per mil, relative to the Cañón Diablo troilite (CDT) standard. Organic carbon (TOC) was determined by treating powdered samples with 6 M HCl to remove the carbonate. The sample was then rinsed to remove the acid. The mass difference between the original sample and the acid-treated residue was used to determine the carbonate content. The dried sample was then combusted and the evolved CO2 was analyzed on the mass spectrometer. During the mass spectrometric analysis the sample peak height was calibrated against organic carbon standards to estimate the organic carbon content. Result and Discussion Framboidal pyrite is the most common typical byproduct of bacterial sulfate reduction (BSR), a process that occurs at temperatures from 0°C up to about 60–80°C (Donahue et al., 2008). The metabolic activity of the sulfate reducing bacteria generally depletes (or fractionates) the resulting sulfide in 34S, by up to 70% (Kalender, 2011). The availability of S content is consistent with controlling δ34Ssulfide in some portions of this study area, but not all. Total organic carbon (TOC) is above 4% for one mineralized sample of the Upper red Formation. Sulfide sulphur and organic carbon distribution shows that pyrite-rich sandstones are the copper ore precursor, and that mineralizing the processes provoked the depletion of both reduced S and organic C as a consequence of interaction with an oxidized Cu-bearing fluid. On the other hand, lowed 34S values are consistent with bacteriogenic derivation of sulphur. Conclusion Taking into account the sedimentary environment, the abundant presence of the former evaporit layers in the host rock, the presence of evaporit layers below and above the mineralized rocks, and the absence of a widespread magmatic sulfur source, it is concluded that the Cu-Co sulfides of the Nahand-Ivand deposits obtained their sulfur by either bacterial or thermochemical reduction of sedimentary sulfate. The examined samples preserved original sedimentary textures (i.e. immature organic matter and sedimentary bedding). These geological evidences point to the fact that a biological (thermochemical) sulfate reduction is unlikely. Therefore, the sulfate-reducing bacteria were responsible for pyrite formation in the examined sample. The S isotope composition of pyrite in this study is related to organic C abundance. Most of the samples show a correlation between S and C, but mineralized samples are relatively enriched in S and TOC content. References Donahue, M.A., Werne, J.P., Meile, C. and Lyons, T.W., 2008. .Modeling sulfur isotope fractionation and differential diffusion during sulfate reduction in sediments of the Cariaco Basin. Geochimica et Cosmochimica Acta, 72(9): 2287–2297. Kalender, L., 2011. Oxygen, carbon and sulphur isotope studies in the KebanPb–Zn deposits, eastern Turkey: An approach on the origin of hydrothermal fluids. Journal of African Earth Sciences, 59(4–5): 341–348. Reichenbacher, B., Alimohammadian, H., Sabouri, J., Haghfarshi, E., Faridi, M., Abbasi, S., Matzke-Karasz, R., Fellin, M., Carnevale, G., Schiller, W., Vasilyan, D. and Scharrer, S., 2011. Late Miocene stratigraphy, palaeoecology and palaeogeography of the Tabriz Basin (NW Iran, Eastern Paratethys). Palaeogeography, Palaeoclimatology, Palaeoecology, 311(1–2): 1–18. Sadati, N., Yazdi, M., Behzadi, M., Adabi, M.H. and Mokhtari, A.A, 2013. The role of organic matter in genesis of sedimentary-hosted stratiform copper deposits in Nahand-Ivand area, NW Iran. Goldschmidt Conference, Firenze Fiera Congress and Exhibition Centre, Florence, Italy.

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Authors: Mohammad Hassan Karimpour, Azadeh Malekzadeh Shafaroudi, Abbas Esmaeili Sevieri, Saeed Shabani, Julien M. Allaz and Charles R. Stern

Introduction The Irankuh mining district area located at the southern part of the Malayer-Isfahan metallogenic belt, south of Isfahan, consists of several Zn-Pb deposits and occurrences such as Tappehsorkh, Rowmarmar 5, Kolahdarvazeh, Blind ore, and Gushfil deposits as well as Rowmarmar 1-4 and Gushfil 1 prospects. Based on geology, alteration, form and texture of mineralization, and paragenesis assemblages, Pb-Zn mineralization is Mississippi-type deposit (Rastad, 1981; Ghazban et al., 1994; Ghasemi, 1995; Reichert, 2007; Timoori-Asl (2010); Ayati et al., 2013; Hosseini-Dinani et al., 2015). Geology of the area consists of Jurassic siltstone and shale and different types of Cretaceous dolostone and limestone. The aim of this research is new geological studies such as revision of old geologic map, study of different types of textures and mineral assemblages within carbonate and clastic host rocks, and chemistry of galena, sphalerite, and dolomite. Finally, we combined these results with isotopic and fluid inclusion data and discussed on ore-fluid conditions. Materials and Methods In order to achieve the aims of this work, at first field surveying and sampling were done. Then, 200 thin and 70 polished thin sections were prepared. Some of the samples were selected for microprobe analysis and galena and sphalerite minerals were analyzed by using JEOL- JAX-8230 analyzer at Colorado University, USA. The chemistry of dolomite and fluid inclusion data are used after Boveiri Konari and Rastad (2016) and stable isotope is used after Ghazban et al. (1994). Discussion The Irankuh mineralization is hosted by carbonate rocks (dolostone and limestone) and minor clastic rocks as epigenetic. Mineralization has occurred as breccia, veinlet, open space filling, spoted, dessiminated, and replacement (carbonate hosted rock). The mineral assemblages are Fe-rich sphalerite, galena, minor pyrite, Fe- and Mn-rich dolomite, bituminous, ankrite, calcite ± quartz ± barite within carbonate host rocks, whereas Fe-rich sphalerite, galena, pyrite, minor chalcopyrite, low Fe-dolomite, quartz, bituminous, ± barite ± calcite are important primary minerals at clastic host rocks. There is positive correlation between Ag and Sb values within galena mineral. Sb/Bi ratio in galena is up to 20, which is an indicator of low temperature deposits (Malakhov, 1968). The Irankuh homogenization temperature (170 to 260 ºC) is higher than that of US Mississippi-type deposits (80 to 120 ºC). Based on comparison of Th and Fe and Cd contents in sphalerite from Irankuh and US deposits (Viets et al., 1992), homogenization temperature of deposit has a positive relation with Fe values and a negative relation with Cd contents in sphalerite. Fe content in Irankuh sphalerite has reached up to 5% and Cd value is lower than 2000 ppm. In addition, carbonate hosted rock hydrothermal dolomites that are Fe-rich and ankrite have formed at some places. The evidence shows that Irankuh ore-fluid is Fe-rich. However, clastic hosted rock hydrothermal dolomites are low-Fe due to reaction of Fe and S resulting in pyrite formation. Based on O isotope (16–19 ‰) value from hydrothermal dolomites (Ghazban et al., 1994), ore-fluid has been derived from continental crust. Results Fe-rich sphalerite and dolomite and ankrite are the most important characteristics of Irankuh mining district. Temperature and Fe-rich nature of ore-fluid and mineralogy signatures of Irankuh area can be used for exploration of this type of mineralization in Iran and the world. The Irankuh mining district is MVT type mineralization. Acknowledgements The Research Division of the Ferdowsi University of Mashhad, Iran, supported this study (Project No. 40221.3). Thanks to Bama Co. (especially Mr. Eslami) for the collaborations. References Ayati, F., Dehghani, H., Mokhtari, A.R. and Mojtahedzadeh, H., 2013. Geochemistry and mineralogy studies of Gushfil Pb-Zn deposit, Irankuh, Isfahan. Analytical and Numerical Methods in Mining Engineering, 6: 83-91 (in Persian). Boveiri Konari, M. and Rastad, E., 2016. Nature and origin of dolomitization associated with sulphide mineralization: new insights from the Tappehsorkh Zn-Pb (-Ag-Ba) deposit, Irankuh Mining District, Iran. Geological Journal, DOI: 10.1002/gj.2875 Ghasemi, A., 1995. Facies analysis and geochemistry of Kolah-Darvazaeh, Goud-Zendan, and Khaneh-Gorgi Pb-Zn deposits from south of Irankuh. M.Sc. thesis, Tarbiat Modares University, Tehran, Iran, 158 pp. (in Persian) Ghazban, F., McNutt, R.H. and Schwarcz, H. P., 1994. Genesis of sediment-hosted Zn-Pb-Ba deposits in the Irankuh district, Esfahan area, west-central Iran. Economic Geology, 89: 1262-1278. Hosseini-Dinani, H., Aftabi, A., Esmaeili, A. and Rabbani, M., 2015. Composite soil-geochemical halos delineating carbonate-hosted zinc–lead–barium mineralization in the Irankuh district, Isfahan, west-central Iran. Journal of Geochemical Exploration, 156: 114-130. Malakhov, A.A., 1968. Bismuth and antimony in galena, indicators of conditions of ore deposition. Geokhimiya, 11: 1283-1296. Rastad, E., 1981. Geological, mineralogical and ore facies investigations on the Lower Cretaceous stratabound Zn – Pb – Ba – Cu deposits of the Irankuh mountain range, Isfahan, west central Iran. Ph.D. thesis, Heidelberg University, Heidelberg, Germany, 334 pp. Reichert, J., 2007. A metallogenetic model for carbonate-hosted non-sulphide zinc deposits based on observations of Mehdi Abad and Irankuh, Central and Southwestern Iran. Ph.D. thesis, Martin Luther University Halle Wittenberg, Halle, Germany, 152 pp. Timoori-Asl, F., 2010. Sedimentology and petrology of Jurassic deposits and Basinal brines studies in formation of Irankuh deposit. M.Sc. thesis, Isfahan University, Isfahan, Iran, 120 pp. (in Persian) Viets, J.G., Hopkins, R.T. and Miller, B.M., 1992. Variation in minor and trace metals in sphalerite from Mississippi Valley-type deposits of the Ozark Region: genetic implications. Economic Geology, 87:1897–1905.

313-334

Authors: Ali Kananian, Fatemeh Ghahramani, Fatemeh Sarjoughian, Jamshid Ahmadian and Kazem Kazemi

Introduction Granitic rocks are the most abundant rock types in various tectonic settings and they have originated from mantle-derived magmas and/or partial melting of crustal rocks. The Oligo-Miocene Feshark intrusion is situated in the northeast of the city of Isfahan, and a small part of Urumieh–Dokhtar Magmatic Arc is between 52º21' E to 52º26'E and 32º50' N to - 32º53' N. The pluton has intruded into lower Eocene volcanic rocks such as rhyolite, andesite, and dacite and limestone. Analytical methods Fifteen representative samples from the Feshark intrusion were selected on the basis of their freshness. The major elements and some trace elements were analyzed by X-ray fluorescence (XRF) at Naruto University in Japan and the trace-element compositions were determined at the ALS Chemex lab. Results The Feshark intrusion can be divided into two phases, namely granodiorite with slightly granite and tonalite composition and quartz diorite with various quartz diorite and quartz monzodiorite abundant enclaves according to Middlemost (1994) classification. The quartz diorite show dark grey and are abundant at the western part of the intrusive rocks. Granodiorite are typically of white-light grey in color and change gradually into granite and tonalite. The granodiorite and granite rocks consist of quartz, K-feldspar, plagioclase, biotite, and amphibole, whereas in the quartz diorites the mineral assemblages between different minerals are very similar to those observed in the granodiorite. However, amphibole and plagioclase are more abundant and quartz and K-feldspar modal contents are lower than in the granodiorite whereas pyroxene occurs as rare grains. They are characterized as metaluminous to mildly peraluminous based on alumina saturation index (e.g. Shand, 1943) and are mostly medium-K calc-alkaline in nature (Rickwood, 1989). Discussion In the Yb vs. La/Yb and Tb/Yb variation diagrams (He et al., 2009), the studied samples show small variations in La/Yb and Tb/Yb ratios, suggesting fractional crystallization. Chondrite-normalized REE patterns (Sun and McDonough, 1989) of all the samples essentially have the same shape with light REE (LREE) enrichment, flat high REE (HREE) and significant negative Eu anomalies. All of the samples exhibit similar trace element abundance patterns, with enrichment in large ion lithophile elements (LILE) and negative anomalies in high field strength elements (HFSE; e.g. Ba, Nb, Ta, P, and Ti) compared to primitive mantle (Sun and McDonough, 1989). The enrichment of LILE and LREE relative to the HFSE and HREE along with Nb, Ta, and Ti anomalies display close similarities to those of magmatic arc granites (Pearce et al., 1984) and also negative Nb–Ti anomalies are thought to be related to the fractionation of Ti-bearing phases (titanite, etc.). Moreover, these are the typical features of arc and / or crustal contamination (Kuster and Harms, 1998), while the negative P anomalies should result from apatite fractionation. The increasing of Ba and slightly decreasing Sr with increasing Rb, indicate that plagioclase fractionation plays an important role in the evolution of the studied intrusion. Tectonic environment discrimination diagrams such as Nb vs. Y, Nb vs. Yb+Ta (Pearce et al., 1984) and Th/Yb vs. Ta/Yb (Pearce, 1983) with enrichment in the LILE and LREE relative to HFSE and HREE and negative anomaly in the Nb, Ti and Eu indicate that their initial magma is generated in the subduction zone related to an active continental margin setting. ‏The rocks genesis determining diagrams such as Nb vs. Nb/U (Taylor and McLennan, 1985), Ti vs. Ti/Zr (Rudnick et al. 2000), (La/Sm)cn vs. Nb/U (Hofmann et al., 1986), and Sr/Y vs. Y (Sun and McDonough, 1989) show that the magma was probably generated by partial melting of amphibolitic continental crust. References He, Y., Zhao, G., Sun, M. and Han, Y., 2009. Petrogenesis and tectonic setting of volcanic rocks in the Xiaoshan and Waifangshan areas along the southern margin of the North China Craton: Constraints from bulk-rock geochemistry and Sr-Nd isotopic composition. Lithos, 114(1-2): 186-199. Hofmann, A.W., Jochum, K.P., Seufert, M. and White, W.M., 1986. Nb and Pb in oceanic basalts: new constraints on mantle evolution. Earth and Planetary Science Letters ,79(1-2): 33-45. Kuster, D. and Harms, U., 1998. post – collisional potassic granitoids from the southern and northwestern parts of the late neoporterozoic East African Orogen: a review. Lithos. 45(1-4):177-195. Pearce, J.A., 1983. The role of sub-continental lithosphere in magma genesis at destructive plate margins. In: C.J. Hawkesworth and M.j. Norry (Editors), continental basalts and mantle xenoliths. Shiva Publications, Nantwhich, pp. 230-249. Middlemost, E.A.A. 1994. Naming materials in the magma/igneous rock system. Earth- Science Review. 37(3-4): 215–224. Pearce, J.A., 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. Rickwood, P.C., 1989. Boundary lines within petrologic diagrams which use of major and minor element. Lithos, 22(4): 247-263. Rudnick, R.L., Barth, M., Horn, I. and McDonough, W. F., 2000. Rutile-Bearing Refractory Eclogites: Missing Link Between Continents and Depleted Mantle. Science, 287(5451): 278-281. Shand, S.J., 1943. The Eruptive Rocks. 2nd edition. John Wiley, New York, 444 pp. Sun, S.S. and McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Geological Society, London, Special Publications, 42, pp. 313-345. Taylor, S.R. and McLennan, S.M., 1985. The continental crust: its compositions and evolution. Blackwell, Oxford, 312 pp.

357-374

Authors: Shokouh Riahi, Nader Fathianpour and Seyed Hassan Tabatabaei

Introduction The growing demand for base metals such as iron, copper, lead and zinc on the one hand and the diminishing of surficial and shallow resources of these elements on the other hand have forced explorationists to focus on detecting deep deposits of these metals. As a result, the discovery of such deep deposits requires more advanced and sophisticated methods in the course of preliminary prospecting stages. Since the discovery of new deposits is getting to be increasingly difficult, deploying new prospecting technologies that employ more deposit attributes in the course of combining exploratory evidence may reduce the exploration costs with lower uncertainties. In the past two decades, a number of new data mining and integrating approaches capable of incorporating direct and indirect mineralization indicators, based on expert knowledge, data, or a combination of both, have been proposed )Bonham-Carter, 1994(. In the first step, the input exploratory data layers are corrected and validated through applying some statistical pre-processing algorithms such as background and outlier removal methods. In order to detect a mineralization occurrence, it is necessary to find the proper exploratory geological, geochemical and geophysical data layers which have direct or indirect associations with the governing mineralization followed by constructing these models in an appropriate GIS platform (Malkzewski, 1999). Due to the imperfect available data and a number of unknown parameters affecting the mineralization process, the application of conventional GIS integration methods such as Boolean or weighted overlay or even fuzzy logic methods alone may not produce appropriate results, pointing to a need for deploying multi-criteria decision-making methods such as TOPSIS. In the present study, the pre-processed exploratory data including geological, remotely sensed geophysical and geochemical imagery were used to detect favorable mineralization zones through applying the multi-criteria decision-making method. Finally, the selected favorable areas in the metallogenic strip located at the south to the south-east of the Sarcheshmeh porphyry copper deposit are prioritized and introduced for further follow up ground exploration operations. Methodology In order to solve complex decision-making problems like the problem of mapping favorable porphyry copper mineralization zones under great uncertainties, the TOPSIS method is considered as an appropriate approach offering significant simplicity, flexibility and capability (Ataei., 2010). The TOPSIS method is considered to be an efficient method due to having very high accuracy, speed, sensitivity as well as being easy to implement and interpret the outputted results (Hwang and Yoon, 1981). It has found many applications in important areas of mining industry where there is a need to make decisions under risky conditions and data uncertainties. One basic issue in applying decision-making methods in the field of mineral exploration is to rank and propose the best possible candidates among all potentially favorable areas for the next stage of mineral exploration. In this regard, the best favorable areas are selected based on exploratory data layers including favorable lithologies, alterations, structures plus geochemical and geophysical anomalies (Pazand et al., 2012). Results and discussion In the first step, the area located south to the southeast of one the largest porphyry copper deposits in Iran known as Sarcheshmeh was investigated for favorable areas using all available exploratory data as mentioned in the previous section using fuzzy logic integration approach in the GIS environment. Evaluating the highly favorable areas presented by the fuzzy logic approach showed great consistency with the already known copper mineralization prospects. Next, the first 20 priorities obtained from the fuzzy logic approach were chosen as the best candidates to be ranked using the TOPSIS multi criteria decision-making method. Among these favorable prospects, the one with the highest coefficient close to the ideal solution of 0.796 was found to be coincident with the Darehzar area that is a well known porphyry copper deposit 12 kilometers south of the Sarcheshmeh deposit. The favorable areas numbered 5 and 8 that correspond to well known porphyry copper mineralization prospects called Sereydoon and North Sereydoon were ranked as the second and third priorities with scores of 0.721 and 0.604, respectively. Other favorable areas ranked by the TOPSIS method were also prioritized and presented for further follow up explorations. To assess the sensitivity of the results obtained by the TOPSIS method, an amount of 10% of the values of each of the criteria were added and the outputted ranking results were compared to that of the original TOPSIS results. It was concluded that a slight change in the values of the criteria would not have significant impact on the results. However, 10 percent change of each criteria weight would greatly affect the prospects priorities obtained by re-applying the TOPSIS method. References Ataei, M., 2010. Multi Criteria Decision Making. Shahrood University Publications, Shahrood, 333 pp Bonham–Carter, G.F., 1994. Geographic information system for geoscientists-molding with GIS. Geological Survey of Canada, Ontario, Canada, 398 pp. Hwang, C.L. and Yoon, K., 1981; Multiple Attribute Decision Making: Methods and Applications, Springer-Verlag, Berlin, 228 pp. Malkzewski, J., 1999, GIS and Multi Criteria Decision Analysis. John Whily and Sons, Canada, 387 pp. Pazand, K., Hezarkhani, A. and Ataei, M., 2012. Using TOPSIS approaches for predictive porphyry Cu potential mapping: A case study in Ahar-Arasbaran area (NW, Iran). Computers & Geosciences, 49(1): 62-71.

397-418

Authors: Amir Ali Tabbakh Shabani, Morteza Delavari Kooshan and Mahsa Hajiabdolrahim Khabbaz

Introduction The Upper Eocene basic volcanic rocks that have cropped out in Karaj formation in the Boumehen and Roudehen area in the east of Tehran are characterized by fibrous zeolites filling their vesicles, cavities and fractures creating amygdale texture. The study area is located structurally in the Central Alborz orogenic belt. The presence of large volumes of shoshonitic magma during the Middle to Late Eocene in southern–central Alborz implies that partial melting to produce shoshsonitic melts was not a local petrological event. Thus, their ages, formation processes, and interpretations are of regional tectonic significance. In this study, we present a detailed petrography, mineral chemistry, and whole-rock geochemistry of high-K (shoshonitic) basic rocks to understand the petrogenesis and source region and to deduce the nature of the tectonomagmatic regime of the Alborz. Materials and methods In this study, we present new major and trace element data for a selection of 4 of the least altered samples by a combination of X-ray fluorescence (XRF) and ICP-OES techniques at the Zarazma Mineral Studies Company. Mineral analyses were obtained by wavelength dispersive X-ray spectrometry on polished thin sections prepared from each rock sample described above for 12 elements using a Cameca SX-50 electron microprobe at the Istituto di Geologia e Geoingegneria Ambientale, C.N.R., University La Sapienza of Rome, Italy. Typical beam operating conditions were 15 kV and probe current of 15 nA. The accuracy of the analyses is 1% for major and 10% for minor elements. A total of 24 point analyses were collected. Results and Discussion The extent of alteration in the study rocks varies from slight to severe and shows porphyritic to glomeroporphyritic textures. Pyroxenes are generally subhedral to euhedral and occur as discrete crystals as well as aggregates. Olivine may occur only as relics filled with iddingsite, chlorite and calcite. Plagioclase is subhedral to euhedral and occurs both as pheocrysts and microliths in the glassy groundmass. The plagioclase crystals are variably sassuratised and sometimes replaced by zeolites. Microprobe data indicate a restricted range of chemical composition for pyroxene falling in diopside and augite fields of ternary pyroxene classification diagram (Morimoto, 1988). The plagioclase composistions have been plotted in the fields of labradorite and bytownite in the orthoclase–albite–anorthite ternary diagram (Deer et al., 1992). On the F1-F2 tectonic discrimination diagram of Nisbet and Pearce (1977), pyroxene compositions plot mainly in volcanic arc basalt field consistent with their whole rock geochemistry. Thermobarometry based on pyroxene composition (Soesoo, 1997) displays a range of temperatures from 1150 to 1250 0C and pressure from 3 to 8 kbar for its crystallization. Whole rock compositions show that the variations of SiO2 contents are narrow (47.08 – 47.47 wt%) and TiO2 (1.1 – 1.24 wt%). Relatively higher contents of K2O show a shoshonitic affinity in the K2O–SiO2 diagram (Peccerillo and Taylor 1976). Trace element and rare earth element (REE) distribution patterns for the basaltic samples normalized to the primitive mantle (McDonough et al., 1992) and chondrite values (Sun and McDonough, 1989) show similar patterns. The samples are all enriched in large-ion lithophile elements (LILEs), such as Rb, Ba, and K, and light rare earth elements (LREEs) ((La/Sm)N= 2.3–3.2) relative to the more immobile elements (e.g., Hf, Ti and Y). The plot of analyzed samples in a series of different tectonic discrimination diagrams shows that the Boumehen-Roudehen alkaline basalts are consistent with characteristics of subduction related (active continental margins) tectonic environments. In addition, enrichment in LILE and depletion in HFSE on spidergram create patterns which are very similar with the pattern of Andean counterparts indicating an arc setting. Acknowledgments Marcello Serracino is thanked for microprobe analyses. The authors are grateful to Journal Manager and reviewers who critically reviewed the manuscript and made valuable suggestions for its improvement. References Deer, W.A., Howie, R.A. and Zussman, J., 1992. An Introduction to the Rock Forming Minerals. Longman, London, 696 pp. McDonough, W.F., Sun, S.-S., Ringwood, A.E., Jagoutz, E. and Hofmann, A.W. 1992. Potassium, Rubidium and Cesium in the Earth and Moon and the evolution of the mantle of the Earth. Geochimica et Cosmochimica Acta, 56(3): 1001-1012. Morimoto, N., Fabries, J., Ferguson, A.K., Ginzburg, I.V., Ross, M., Seifert, F.A., Zussman, J., Aoki, K. and Gottardi, G., 1988. Nomenclature of pyroxenes. American Mineralogist, 73)9-10:( 1123–1133. Nisbet, E.G. and Pearce, J.A., 1977. Clinopyroxene composition in mafic lavas from different tectonic settings. Contributions to Mineralogy and Petrology, 63)2:(149-160. Peccerillo, A. and Taylor, S.R.,1976 . Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey. Contributions to Mineralogy and Petrology, 58(1): 63-81. Soesoo, A. 1997. A multivariate statistical analysis of clinopyroxene composition: Empirical coordinates for the crystallisation PT- estimations. Journal of the Geological Society of Sweden, 119(1): 55-60. Sun, S.S. and McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts; implications for mantle composition and processes. In: A.D., Saunders and M.J., Norry (Editors), Magmatism in the ocean basins. Geological Society, London, Special Publications, 42. 313-345.

439-461

Authors: Zahra Vahedi Tabas, Seyyed Saeid Mohammadi and Mohammad Hossein Zarrinkoub

Introduction Basaltic volcanoes are one of the volcanisms that have occurred in different parts of the world. The study of these lavas is important for petrologists, because they are seen in different tectonic settings and therefore diverse mechanisms affect their formation (Chen et al., 2007). Young volcanic rocks such as Quaternary basalts are one of latest products of magmatism in Iran that are related to deep fractures and active faults in Quaternary (Emami, 2000). The study area is located at 140km east of Birjand at Gazik 1:100000 geological map (Guillou et al., 1981) and have 60̊ 11' to 60̊ 15 '27" eastward longitude and 32̊ 33' 24" to 32̊ 39' 10" northward latitude. On the basis of structural subdivisions of Iran, this area is located in the northern part of the Sistan suture zone (Tirrul et al., 1983). Because of the importance of basaltic rocks in Sistan suture, this research is done with the aim of investigating the petrography and mineralogy of basaltic lavas, the nature of basaltic and intermediate magmatism and finally determination of tectonomagmatic regime. Materials and methods After field studies and sampling, 85 thin sections were prepared and carefully studied. Then ten samples with the lowest alteration were analyzed for major elements by inductively coupled plasma (ICP) technologies and trace elements were analyzed using inductively coupled plasma mass spectrometry (ICP-MS), following a lithium metaborate/tetraborate fusion and nitric acid total digestion at the Acme laboratories, Vancouver, Canada. Electron probe micro analyses of clinopyroxene and olivine were done at the Iranian mineral processing research center (IMPRC) by Cameca SX100 machine. X-ray diffraction analysis of minerals was done at the X-ray laboratory of the University of Birjand. Results In 60km south of GaziK at the east of the southern Khorasan province and the northern part of the Sistan suture zone, volcanic rocks with intermediate (Oligomiocene) and basic (Quaternary) compositions outcropped above ophiolitic units. Electron probe micro analyzer (EMPA) data indicated that clinopyroxene in basalt is diopside and olivine from chrysolite type with Mg# around 81-82 percent. The whole rocks geochemical data prove calc-alkaline and alkaline nature for andesites and basalts, respectively. Trace element patterns, especially for andesites show enrichment in Ba, K, Cs, Sr and Th, depletion in P, Nb, Ti and enrichment in LREE relative to HREE. Electron probe micro analyses of clinopyroxene in olivine basalt support alkaline nature and within plate tectonic setting for this rock. Thermobarometry of clinopyroxene in olivine basalt record crystallization conditions about 1200 oC and 6-10kbars. Discussion The origin of intraplate volcanism is diverse and not always well understood. Most intraplate volcanos have been attributed to (i) mantle plumes and hot spots, (ii) continental rift, (iii) back-arc extension and (iv) lithosphere delamination and thinning (Chen et al., 2007). Although volcanism at intraplate settings is less common than along mid-ocean ridges and subduction zones, it is of significant importance for both preventing geological hazards and understanding mantle geochemistry. It is believed that alkaline oceanic island basalts (OIB) are only derived from the asthenospheric mantle (Alici et al., 2002). However, the intracontinental alkaline magmas can be produced by partial melting of metasomatized mantle enriched in LREE and LILE (Upadhyay et al., 2006). On the basis of trace element diagrams, Ratouk basaltic rocks placed within plate volcanic zone (WPVZ) and andesitic samples have been located within the active continental margin (ACM). The studies that took place about young basaltic volcanism (Alishahi, 2012; Mollashahi et al., 2011; Ghasempour et al., 2011; Pang et al., 2012; Walker et al., 2009) have shown that the mechanisms of their occurrence are similar such that all of them have been formed in intraplate extensional environments and active fault zone and originated from enriched mantle or asthenosphere. Lithospheric thickness maps derived from the speed of shear waves show that the lithosphere is thin in east of Iran and volcanic activity has occurred along strike-slip faults (Walker et al., 2009). Therefore, according to other similar basaltic eruptions that have occurred in the Sistan suture zone, we can say that all of them are from the same origin and as a result of deep fractures within continental plates that provide conditions for the eruption of basaltic magma. Andesitic units in the Ratouk area are located within the active continental margin and show similar characteristics to rocks of the Subduction Zone in terms of composition. Acknowledgements The authors would like to thank reviewers for the constructive comments which greatly contributed to the improvement of the manuscript. References Alici, P., Temel, A. and Gourgaud, A., 2002. Pb-Nd Sr isotope and trace element geochemistry of Quaternary extension-related alkaline volcanism: a case study of Kula region western Anatolia, Turkey. Journal of Volcanology and Geothermal Research, 115(3): 487-510. Alishahi, E., 2012. Petrology and Geochemistry of volcanic rocks in Nasfandeh area (east of Nehbandan) –Iran. M.Sc. Thesis, University of Birjand, Birjand, Iran, 211 pp. (in Persian with English abstract) Chen, Y., Zhang, Y., Graham, D., Su, S. and Deng, J., 2007. Geochemistry of Cenozoic basalts and mantle xenoliths in Northeast China. Lithos, 96(1): 108–126. Emami, M.H., 2000. Magmatism in Iran. Geological Survey of Iran, Tehran, 608 pp. Ghasempour, M.R., Byabangard, H., Boomeri, M. and Moridi, A., 2011. Geochemistry and tectonic setting of Plio-Quaternary basaltic rocks in SE Nehbandan, eastern Iran. Iranian Journal of Crystallography and Mineralogy, 18(4): 695-708. (in Persian with English abstract) Guillou, Y., Maurizot, P., Vaslet, D. and Dellavillen, H., 1981. Geological map of Gazik, Scale1:100000. Geological Survey of Iran. Mollashahi, N., Zarrinkoub, M.H., Mohammadi, S.S. and Khatib, M.M., 2011. Petrology of young volcanic in Hamun Lake area (East of Iran). Iranian Journal of Crystallography and Mineralogy, 19(3): 519-528. (in Persian with English abstract) Pang, K.W., Chung, S.L., Zarrinkoub, M.H., Mohammadi, S.S., Yang, H.M., Chu, C.H., Lee, H.Y. and Lo, C.H., 2012. Age, geochemical characteristics and petrogenesis of Late Cenozoic intraplate alkali basalts in the Lut–Sistan region, eastern Iran. Chemical Geology, 306-307: 40-53. Tirrul, R ., Bell, L.R., Griffis, R.J. and Camp, V.E., 1983. The Sistan suture zone of eastern Iran. Geological Society of America Bulletin, 94(1): 134-150. Upadhyay, D., Raith, M.M., Mezger, K. and Hammerschmidt, K., 2006. Mesoproterozoic rift-related alkaline magmatism at Elchuru, Prakasam Alkaline Province, SE India. Lithos, 89(3): 447-477. Walker , R.T., Gans, P., Allen, M., Jackson, J., Khatib, M.M. and Zarrinkoub, M.H., 2009. Late Cenozoic Volcanism and rates of active faulting in eastern Iran. Geophysical Journal International, 177: 783-805.

483-507

Authors: Faezeh Nabiloo, Behnam Shafiei Bafti and Arash Amini

Introduction Upper part of Elika Formation (middle Triassic) in the central Alborz as one of the most important fluorite districts in Iran is the host of some carbonate rock-hosted fluorite deposits such as Kamarposht, Pachi-Miana, Shashroodbar, Era (Alirezaee, 1989; Gorjizad, 1996; Rastad and Shariatmadar, 2001; Rajabi et al., 2013; Vahabzadeh et al., 2013; Zabihitabar and Shafiei, 2015). One of the main active fluorite mines in the central Alborz is Kamarposht which is located at the southeast of DoAb in the Mazandaran province. The Kamarposht mine has 75000 tons of ores and mining there has begun in 2005. The effects and evidences of underground mining in the northern and southern parts of this mine indicate high-grade and coarse-grained ore zones which have fluorite, galena and barite. Until now, basic economic geology studies in the Kamarposht mine including mineralogy, fabric and texture of mineralization for introducing a new fluorite mine in Iran have not been carried out. The present study is based on field observations and macroscopic as well as microscopic studies aimed at identification of morphology and mode of occurrence of the ore body, mineralogy and fabric of mineralization and discussion of as well as presentation of a new genetic model for the Kamarposht mine. Materials and methods For the present research study, field geology and sampling were carried out to collect 100 samples from various fluorite ore-types and carbonate host rocks. The samples prepared for thin section (n=55) and polished-thin sections (n=22). Results Field observations indicate that economic mineable ore zones of the Kamarposht mine are mainly hosted by dolomitic limestone and silicified carbonate horizons of the Elika Formation. The ore zones have fluorite, barite and galena which are mainly located in fractured and faulted zones as well as karstic cavities in the host horizons. Coarse grain and euhedral fluorites with various colors, significant presence of barite as massive and vein, abundant galena and near contact between mineralization zones in carbonate host rocks (Elika Fm.) and pyrite-bearing coalified shales (base of Shemshak Fm.?) as faulted and/or interbedded are all distinctive geological features for the Kamarposht mine. Fluorite mainly occurs as interrupted, dense and voluminous massive bodies with/without galena which have occupied cavities and open spaces between brecciated fragments of dolomitic limestone relative to the form of disseminate grains, veinlets and geode. Massive and voluminous accumulations of barite in dissolution and karstic cavities and also as discordant veins relative to the bedding of the host rock which have been generated radial, breccias and zebra structures in barite ores. Galena occurs as veinlets and breccias with medium to coarse grain size with/without fluorite in dolomitic and silicified host rocks and also as vein-veinlets into and/or rime of massive barites. Discussion Based on field evidences and mode occurrence of ore minerals and ore textures, mineralization in the Kamaposht mine has occurred as syn-diagenetic (primary) and post-diagenetic/epigenetic (main) fabrics. Ores with disseminate particles of ore minerals, stylolite, geode and tiny veinlets fabrics have been interpreted as primary textures that co-exist with diagenesis of host rocks. These fabrics have been formed under diagenetic processes such as nucleation, re-crystalization and disolution of host rocks by diagenetic phreatic reactions that have caused increasing temperature-pressure due to increasing depth of burial diagenesis (Force et al., 1991; Fontbote and Gorzawski 1990; Rastad and Shariatmadar, 2001; Haeri-Ardakani et al., 2013). The main textures of mineralization in the Kamarposht mine namely open-space filling fabrics including veins and breccias fabrics with replacement, network and zebra textures which are associated with dolomitized and silicified host rock have been caused by late and/or post-diagenetic processes (Fontbote and Gorzawski 1990; Sangster, 1996; Leach et al., 2005). Change and conversion of diagenetic mineralization fabrics to epigenetic ones which is associated with developing and increasing the intensity of fluorite-barite-galena mineralization, is attributed to the function of hydrothermal solutions/basianl brines generated due to the main Cimerian orogeny (Rajabi et al., 2013). The increasing dissolution of host rock along with its dolomitization and silicification were probably the main processes responsible for epigenetic mineralization in the Kamarposht mine. Finally, the present study shows that the Kamarposht mine is a fluorite-rich MVT deposit with poly-genetic origin. References Alirezaee, S., 1989. Contribution to stratigraphy and mode of generation of F-Pb-Ba deposits in Triassic of eastern Alborz. M.Sc. Thesis, Tehran University, Tehran, Iran, 87 pp. (in Persian with English abstract). Fontbote, L. and Gorzawski, H., 1990. Genesis of the Mississippi Valley-Type Zn-Pb Deposit of San Vicente, Central Peru: Geologic and Isotopic (Sr, O, C, S, Pb) Evidence. Economic Geology, 85(7): 1402-1437 Force, E.R., Eidel, J.J. and Maynard, J.B., 1991. Sedimentary and diagenetic mineral deposits: A basin analysis approach to exploration. Society of Economic Geologist Publication, Reviews in Economic Geology 5 , USA, 217 pp. Gorjizad, H., 1996. Study on geology, mineralogy, facies analysis and genesis of Pachi Miana fluorite deposit. M.Sc. Thesis, Tarbiat Modaress University, Tehran, Iran, 156 pp. (in Persian with English abstract) Haeri-Ardakani, O., Al-Asem, I., Coniglio,M. and Samson, I., 2013. Diagenetic evolution and associated mineralization in Middle Devonian carbonates, southwestern Ontario, Canada. Bulletin of Canadian Petroleum Geology, 61(1): 41–58. Leach, D., Sangster, D., Kelley, K., Large, R., Garven, G., Allen, C., Gutzmer, J. and Walters, S., 2005. Sediment- hosted lead-zinc deposits: a global perspective. In: J. Hedenquist, J. Thompson, R. Goldfarb, and J. Richards, (Editors), 100th Anniversary Volume of Economic Geology, Society of Economic Geologist Publication, USA, pp. 561-607. Rajabi, A., Rastad, E. and Canet, C., 2013. Metallogeny of Permian-Triassic carbonate-hosted Zn-Pb and F deposits of Iran: A review for future mineral exploration. Australian Journal of Earth Sciences, 60(2): 197-216. Rastad, E. and Shariatmadar, A., 2001. Sheshroodbar fluorite deposits, sedimentary and diagenetic fabrics and its depositional environment (Savad Kuh, Mazandaran province). Journal of Geosciences, 10(41-42): Sangster, D.F., 1996. Carbonate-hosted lead-zinc deposits. Society of Economic Geology, Special Publication No.4, 664 pp. Vahabzadeh, G., Khakzad, A., Rasa, I.¬ and Mosavi, M.R., 2014. Fluorite REEs geochemistry in fluorite deposits of central Alborz. New Finds of Applied Geology, 16(1): 58-70. (in Persian with English abstract) Zabihitabar, Sh. and Shafiei, B., 2015. Mineralogy and mode occurrence of sulfides, sulfates and carbonates at fluorite mines in East of Mazandaran province. Iranian Journal of Geology, 33(1): 62-78. (in Persian with English abstract)

545-559

Authors: Atefeh Ghaedi, Abbas Moradian and Hamid Ahmadipour

Introduction Borate deposits are often important constituents of economic non - marine evaporates. They produce under arid climatic conditions in playa lakes (Floyd et al., 1998). In the south – western parts of the Kerman province, such as the Khatoonabad area (east of the city of Shahr –e –Babak) and Robat – Marvast basin (west of Shahr – e – Babak), there are several borate deposits. They can be seen mainly in Sanandaj – Sirjan depressions and they occur as borate bearing nodules beneath a thin layer of soil. In general, boron considerably reduces the thermal expansion of glass, provides good resistance to vibration, high temperatures and thermal shock, and improves its toughness, strength, chemical resistance and durability. It also greatly reduces the viscosity of the glass melt. These features, and others, allow it to form superior glass for many industrial and specialty applications (Garrett, 1998). In the past, the ancient residents used them as co-melting matters. Ulexite which is frequently found in the Khatoonabad playa (at 30 km South East of Shahr Babak) have Jewel properties (Ghaedi et al., 2014). Materials and methods After reviewing and Library Studies, geological field studies on the borate deposits were carried out from Shahr – e – Babak Playa. In order to take better samples, several pits were excavated with a depth of 30 cm to 1 meter so that borate minerals became apparent. X-ray diffraction analysis (IMIDRO, Karaj), and ICP AES (ALS CHEMEX, Canada) methods were carried out on representative samples taken from the studied area. Discussion Field observations show that in the studied areas, borate bearing basins are fed by rivers which have originated from Sanandaj – Sirjan metamorphic rocks, Nain – Baft colored mélanges and igneous rocks of Urumieh – Dokhtar magmatic belt. Borate minerals also occur in fibrous aggregates and massive forms. Mineralogy XRD results show that the studied borate minerals mainly belong to the hydrated borates and contain ulexite, borax, gowerite, sassolite and inyoite. Geochemichal data indicate that the boron is the dominant constituent in the studied playa. Borate minerals are divided into two groups of hydrated and non-hydrated borate category (Palache et al., 1952.; Garrett, 1998). Both hydrated and non-hydrated borate minerals have been formed in the Shahr-e-Babak playa. Hydrated borate in the study areas: Hydrated borates are those borates in which water molecules are involved (Garrett, 1998). In the studied area, the hydrated borate minerals include: Borax, Ulexite, Inyoite, Gowerite. Non-hydrated borate in the study areas: In the Shahr-e-Babak playa, Sassolite non-hydrated borate minerals are abundant. According to the XRD analyses performed on samples from the study areas, the hydrated borate minerals are more important minerals. The main economic valuable minerals include: 1- Ulexite (NaCaB5O9.8H2O): Crystal Data: Triclinic. Point Group: 1 (Ghose et al., 1978). In the Shar – e - Babak playa, ulexite occurs as deposits with massive, cauliflower-like nodules and fibrous textures. 2- Borax (Na2B4O5(OH)4 •8H2O): Crystal Data: Monoclinic. Point Group: 2/m. Crystals are commonly short to long prismatic [001] (Levy and Lisensky, 1978). In the studied borate samples, it can be found in association with the other borate minerals, and often occurs in the form of salt marsh. 3- Gowerite (CaB6O8(OH)4 •3H2O): Crystal Data: Monoclinic. Point Group: 2/m (Erd et al., 1959). In the Khatoonabad samples, it was found as prismatic and spherical crystals along with ulexite. 4- Inyoite (CaB3O3 (OH)5 •4H2O): Crystal Data: Monoclinic. Point Group: 2/m (Christ, 1953). This mineral has been detected in the studied area by XRD. Sassolite (H3BO3): Crystal Data: Triclinic. Point Group: 1 and as scaly pseudohexagonal crystals (Allen and Kramer, 1957). This mineral is found frequently in the Marvast Playa. Geochemistry Geochemical data indicate that in the studied playa, boron is very abundant. Good correlation between the elements, such as B and Ca confirms the formation of Calcium bearing borate mineral in the studied areas. Origin Field observations show that in the studied areas, borate bearing basins are fed by rivers which have originated from the Sanandaj – Sirjan metamorphic rocks, Nain – Baft colored mélanges and igneous rocks of the Urumieh – Dokhtar magmatic belt. Result The XRD results show that the studied borate minerals mainly are hydrated ones and contain ulexite, borax, gowerite, sassolite and inyoite. Geochemichal data confirm the frequency of boron in the playa. Good correlation between the elements such as B and Ca verifies the formation of Calcium bearing borate mineral in the studied areas. Acknowledgements The authors wish to thank IMIDRO for performing XRD analyses. References ‏‏ Allen, R.D. and Kramer, H., 1957. Ginorite and sassolite from Death Valley, California. American Mineralogist, 42(1-2): 56-61.‏ Christ, C.L., 1953. Studies of borate minerals, 2. X-ray crystallography of inyoite and meyerhofferite -x-ray and morphological crystallography of 2CaO. 3B2O3. 9H2O. American Mineralogist, 38(1 - 11): 912-918. Erd, R.C., McAllister, J.F. and Almond, H., 1959. Gowerite, a new hydrous calcium borate, from the Death Valley Region, California. American Mineralogist, 44(9-10): 911-919.‏ Floyd, P.A., Helvaci, C. and Mittwede, S.K., 1998. Geochemical discrimination of volcanic rocks associated with borate deposits: an exploration tool? Journal of Geochemical Exploration, 60(3): 185-205.‏ Garrett, D.E., 1998. Borates: handbook of deposits, processing, properties, and use. Academic Press, USA, 483 pp. Ghaedi, A., Moradian, A. and Ahmadipour, H., 2014. Reviewing and introduction of mineralogical properties of Ulexite an unknown gem in Khatoonabad (Shahr Babak, Kerman Province). The 1st National Symposium of Gemology- Crystallography of Iran, Shahid Bahonar University of Kerman, Kerman, Iran. Ghose, S., Wan, C. and Clark, J.R., 1978. Ulexite, NaCaB5O6 (OH)6 . 5H2O: structure refinement, polyanion configuration, hydrogen bonding, and fiber optics. American Mineralogist, 63(12): 160–171. Levy, H.A. and Lisensky, G.C., 1978 .Crystal structures of sodium sulfate decahydrate (Glauber's salt) and sodium tetraborate decahydrate (borax). Redetermination by neutron diffraction. Acta Crystallographica, 34(12): 3502-3510. Palache, C., Berman, H. and Frondel, C., 1952. Dana's System of Mineralogy. Geologiska Föreningen i Stockholm Förhandlingar, 74(2): 218-219.‏

587-616

Authors: Fayeq Hashemi, Fardin Mousivand and Mehdi Rezaei-Kahkhaei

Introduction The Varandan Ba-Pb-Cu deposits are located15 km southwest of the town of Qamsar and approximately 7 km south west of the Qazaan village, in the Urumieh- Dokhtar magmatic arc. The Kashan region that is situated in west-central Iran hosts several barite-base metal deposits and occurrences, the biggest ones are the Varandan Ba-Pb-Cu (case considered in this study) and the Tapeh-Sorkh (Khalajmaasomi et al., 2010) and Dorreh Ba (Nazari, 1994) deposits. Previous researchers (Izadi, 1996; Farokhpey et al., 2010) have proposed an epithermal model for formation of the Varandan deposit. However, based on some feature of the deposit, it seems that this genetic model may not be correct. Therefore, it is necessary to do more precise research studies on the deposit. The main purpose of this paper is to discuss the genesis of the Varandan deposit based on geological, ore facies, mineralogy, wall rock alterations, and geochemical studies. Materials and methods A field study and sampling was performed during the summer of 2013. To assess the geochemical characteristics of the deposit, about 17 systematic samples from different ore facies of the first, second and third sub-horizon were collected for petrography and mineralogy, and for inductively coupled plasma-atomic emission spectroscopy(ICP-AES), X-ray diffraction (XRD) and X-ray fluorescence (XRF) geochemical analysis methods. The microscopic studies were done in the optics laboratory of the Shahrood University, and the geochemical analyzes were conducted in laboratories of the Center of Research and Mineral Processing Ore Minerals of Iran, Karaj, Iran. Results The host sequence in the Varandan deposit involves three units, from bottom to top: Unit1: grey, green siliceous tuff, brecciated tuff, crystal tuff and andesite; Unit2: white grey nummulitic limestone, limy tuff and marl: and Unit3: tuff breccia and crystal lithic tuff. Mineralization in the Varandan deposit has occurred as four ore sub-horizons in Unit1, as lenticular to tabular ore bodies concordant to layering of the host rocks. Based on textural, structural and mineralogical studies, the Varandan deposit consists of five ore facieses including: 1) veins-veinlets (stringer zone) that involves cross-cuting barite, quartz and sulfide veins-veinlets, 2) brecciated barite and massive pyrite (vent complex zone) involving replacement texture, 3) massive barite and sulfide (massive zone), 4) alternations of barite- and galena- rich bands (Bedded-banded zone) and; 5) iron-manganese-bearing hydrothermal-exhalative sediments. Primary ore minerals are barite, galena, chalcopyrite, pyrite, sphalerite, tetrahedrite, magnetite, oligiste, braunite, pyrolusite and bornite, accompanied with secondary minerals such as native copper, cuprite, digenite, covellite, chalcosite, goethite, hematite and malachite. Gangue minerals consist of chlorite, sericite, quartz and calcite. Major wall rock alterations in the deposit are chloritic and quartz- sericitic. For determining the type of ore of the Varandan deposit, the Cu/Zn ratio for the barite and sulfide ore of the first, second and third sub-horizon are 1.08, 0.12 and 11.08, respectively. This lies in the yellow ore for the first and third sub-horizon, and it falls in the black ore for the second sub-. Discussion According to the basic characteristics of mineralization such as geometry of ore bodies, textures and structures, ore facies, wall rock alterations, mineralogy, fluid inclusions data, metal zonation and geochemical features, the Varandan deposit could be classified as a bimodal-felsic or Kuroko-type voclanogenic massive sulfide (VMS) deposit, similar to those of the Hokuroko basin in Japan (Ohmoto and Skinner, 1983; Hoy, 1995, Huston et al., 2011). The Varandan deposit has been formed in an intra-arc setting due to subduction of the Neo-Tethyan oceanic crust beneath the Iranian plate during the Middle Eocene. Acknowledgements The authors are grateful to the Grant Commission for research funding of Iranian Mines and Mining Industries Development and Renovation Organization (IMIDRO) and the University of Shahrood. References Farokhpey, H., Shamsi-Poor, R. and Nasre-Esfahani, A. 2010. Economic petrology of granitoid Ghazaan: study of metal deposit. The Conference on Applied Petrology, Khorasgan Azad university, Tehran, Iran. Hoy, T., 1995. Noranda/kuroko Massive Sulphide Cu-Zn deposits. In: D.V. Lefebure and G.E. Ray (Editors), Selected British Colombia Mineral deposit Profiles, volum 1- Metallics and Coal. British Columbia Ministry of Energy of Employment and Investment open file, Canada, pp. 53-54. Huston, D., Relvas, J., Gemmell, J.B. and Drieberg, S., 2011. The role of granites in volcanic-hosted massive sulphide ore-forming systems: an assessment of magmatic-hydrothermal contributions.Journal of Mineralium Deposita, 46(5-6): 473-507. Izadi, H., 1996. Geology, petrografy and genises of Ba-Pb Kashan Ghamsar Ghazaan. M.Sc. thesis, Khorasgan Azad university, Tehran, Iran. 160 pp. Khalajmaasomi, M., Lotfi, M. and Nazari, M., 2010. Tapeh-Sorkh Mine mineralization model designation Bijegan-Delijan Central Province. Journal of Land and Resources, 1(2): 33-43. (in Persian) Nazari, M., 1994. Study of mineralogy and ore genesis Dorreh deposit in the Kashan. M.Sc. Thesis, Tarbiat-moallem University, Tehran, Iran, 147 pp. (in Persian with English abstract) Ohmoto, H. and Skinner, B.L., 1983. The Kuroko and related volcanogenic massive sulphide deposits: Introduction and summary of new findings. In: H. Ohmoto and B.J. Skinner (Editors), Kuroko and Related Volcanogenic Massive Sulphide Deposits. Economic Geology, Canada, pp. 1-8.

1-23

Authors: Heydar Asgharzadeh Asl, Behzad Mehrabi and Ebrahim Tale Fazel

Introduction The Ahar-Arasbaran metallogenic area (Qara Dagh zone) is located in the northwest of Iran and the western part of the Mazandaran Sea. At the base of the structural classification from Nabavi (1976), this area is situated in the Alborz-Azerbijan magmatic belt. Sheviar Dagh (Ahar batholite) intrusive suite, subvolcanic and volcanic accompanied rocks with east-west trending and 30 km long serves as the main Eocene-Oligocene magmatic event in the north of the Ahar province. Considering geochemistry, this assemblage includes two shoshonitic and calc-alkaline to high-K calc-alkaline series which are the shoshonitic series in the central part and the calc-alkaline series outcrop in the western and eastern part (Aghazadeh, 2009). Textural characteristic, mineral chemistry and fluid inclusion studies were carried out at the tree part of the Agh-Daragh prospecting area. Material and methods A total of 50 samples were collected from the host rocks (including 4 trench and 250 m), ore deposit and altered rocks. Ten altered samples were analyzed for their mineral recognition by X-ray diffraction in the Iran Mineral Process and Research Center (IMPRC). Electron microprobe analyses (EMPA) and backscattered electron (BSE) images of minerals were obtained using a Cameca SX100 electron microprobe in the Iran Mineral Process and Research Center (IMPRC). An accelerating voltage of 15 to 25 kV and beam current of 20 mA was used for all analyses. Typical spot sizes ranged from 2 to 5 μm. A total of 5 double-polish thin sections representative of quartz samples were selected from mineralized veins after petrographic and field studies. Fluid inclusion microthermometry was conducted using a Linkam THMS600 heating–freezing stage (-190°C to +600°C) mounted on a ZEISS Axioplan2 microscope in the fluid inclusion laboratory of the school of Earth Sciences of the Kharazmi University. The heating rate was 5–10 °C/min at higher temperatures (>100°C), with a reproducibility of ±1°C. However, it was reduced to 0.1–0.5°C/min near phase transformation, with a reproducibility of ±0.1°C. Results Mineralization that occurs in the area is mainly related to the Sheiviar Dagh intrusive rocks and it includes a variety of types of skarn, porphyry- and vein-type, epithermal and intrusion related deposits. Agh Daragh mineralization occurs at least in three states including: 1) stockwork-disseminated, 2) vein-type and 3) replacement (skarn). In order to determine the nature and characteristics of granodiorites hosted Ayran Goli mineralization, the biotites points were analyzed. The Ayran Goli granodiorite with calc-alkaline nature is related to orogenic zones that is associated with subduction zones. To determine the chemical properties of the minerals in Gowdal skarn mineralization, garnet and chlorite have been used for analysis which are often located at repidolite and picnochlorite positions. Electron micro probe analysis (EMPA) of magnetite from the Chupanlar area showed that it belongs to porphyry and Kiruna type deposits. Based on the observations made, three types of aqueous fluid inclusions were distinguished in the quartz-sulfide veins, including halite-saturated aqueous (H2O–NaCl±KCl), aqueous two-phase (H2O–NaCl±CaCl2), and monophase liquid and vapor fluid inclusions. Discussion Because of the lack of CO2-bearing fluid inclusions phase in the samples, we used a temperature-pressure relationship intersection in order to obtain the depth of mineralization. However, but at this study salt-rich inclusions (type 1) the dissolution of halite homogeneous solid phase (Bodnar, 1994) were used in order to estimate the standing deposit. Considering the temperature of the liquid-vapor homogenization (Thl-v), temperatures between 201 to 474°C, homogenization halite (TmNaCl) between 196 to 434°C (48 wt% NaCl eq.) in the solid phase inclusions with halite, minimum and the maximum pressure between 4.0 and 7.2, respectively that occur at 0.4 to 2.7 kb (average of 5.1 kb and 4 km depth) under lithostatic pressure. These conditions are consistent with the occurrence of gold porphyry copper deposits introduced by Hedenquist et al., (1998). The presence of gas-phase inclusions (type 3), gas-rich (type 2) and a solid-bearing phase, halite (type 1) in a mixture of fluid inclusions indicates the occurrence of fluid immiscibility (Bodnar, 1995; Fournier, 1999). In such circumstances, homogenization temperature inclusions are trapped as their temperature is taken. Petrographic evidence on the simultaneous presence of these two categories is stored as the initial fluid temperature up 400 to 500°C with boiling and fluid immiscibility. References Aghazadeh, M., 2009. Petrology and geochemistry of the Anzan-Khan Kandi and Sheivier Dagh granitoids (north and east of Ahar, East of Azerbijan). PhD thesis, Tarbiat Modares University, Tehran, Iran, 493 pp. (in Persian with English abstract) Bodnar, R.J., 1994. Synthetic fluid inclusions: XII: the system H2O–NaCl. Experimental determination of the halite liquidus and isochores for a 40 wt.% NaCl solution. Geochimica et Cosmochimica Acta, 58(3): 1053–1063. Bodnar, R.J., 1995. Revised equation and table for determining the freezing point depression of H2O-NaCl solutions. Geochimical et Cosmochimica Acta, 57(3): 683-684. Fournier, R.O., 1999. Hydrothermal processes related to movement of fluid from plastic to brittle rock in the magmatic-epithermal environment. Economic Geology, 94(8): 1193-1212. Hedenquist, J.W., Arribas, A. and Reynolds, T.J., 1998. Evolution of an intrusion-centered hydrothermal system: Far Southeast Lepanto porphyry and epithermal Cu-Au deposits, Philippines. Economic Geology, 93(4): 374-404. Nabavi, M.H., 1976. An introduction to the Iranian geology. Geological Survey of Iran, Tehran, 110 pp.

57-72

Authors: Nargess Shirdashtzadeh, Ghodrat Torabi and Ramin Samadi

Introduction Study of the petrology of the ophiolites as the relics of ancient oceanic lithosphere, is a powerful tool to reconstruct Earth’s history. Mantle peridotites have mostly undergone alteration and serpentinization to some extent. Thus, the relics of metamorphic signatures from the upper mantle and crustal processes from most of the peridotites have been ruined. Several recent papers deal with the mantle peridotites of Nain Ophiolite (e.g. Ghazi et al., 2010). However, no scientific work has been carried out on the metamorphosed mantle peridotites. The study area of the Darreh Deh that is located in the east of the Nain Ophiolite, is composed of huge massifs of metamorphosed mantle peridotites (i.e. lherzolite, clinopyroxene-bearing harzburgite, and harzburgite, and small volumes of dunite), characterized by darker color, higher topographic relief, smaller number of basic intrusives, lower serpentinization degree, and amphibolite-facies metamorphism. In this study, the petrography and mineralogy of metamorphosed peridotites in the Darreh Deh has been considered based on geochemical data. Geological Setting The Mesozoic ophiolitic mélange of Nain is located in the west of CEIM, along the Nain-Baft fault. As a part of a metamorphosed oceanic crust, it is mainly composed of harzburgite, lherzolite, dunite and their serpentinized varieties, chromitite, pyroxenite, gabbro, diabasic dike, spilitized pillow lava, plagiogranite, amphibolite, metaperidotites, schist, skarn, marble, rodingite, metachert and listwaenite (Shirdashtzadeh et al., 2010, 2014a, 2014b). Geochemical investigations indicate a suprasubduction zone in the eastern branch of the Neo-Tethys Ocean (Ghasemi and Talbot, 2006; Shirdashtzadeh et al., 2010, 2014a, 2014b). Materials and Methods Chemical analyses of mineral compositions were carried out using a JEOL JXA8800R wavelength-dispersive electron probe micro-analyzer (accelerating voltage of 15 kV and a beam current of 15 nA) at the Centre for Cooperative Research of the Kanazawa University (Kanazawa, Japan). The Micro-Raman spectroscopy (a HORIBA Jobin Yvon, LabRAM HR800 system equipped with a 532 nm Nd:YAG laser of Showa Optronics co., Ltd, J100GS-16, and an optical microscope of Olympus, BX41, Kanazawa University) were used in determination of serpentine minerals. Results The lherzolite is primarily composed olivine, orthopyroxene, clinopyroxene and Cr-spinel, but secondary hydrous and non-hydrous Mg-silicate minerals have been formed during the further serpentinization and metamorphism. Lherzolite is including of olivine (~70 Vol%, forsterite-rich), orthopyroxene (~15-20 Vol%, enstatite – bronzite), clinopyroxene (5-7 Vol%, diopside - augite), and vermicular brown Cr-spinel (<5 Vol%), chlorite (pennine – talc-chlorite), lizardite, chrysotile, talc, tremolite (tremolite - tremolitic hornblende), and neoblasts of metamorphic olivines (forsterite). Harzburgite is characterized by olivine (>60-70 Vol%, chrysolite), orthopyroxene (~30 Vol%, bronzite), a small amount of clinopyroxene, and subhedral dark brown Cr-spinel, talc, tremolite, magnetite, and chlorite. Dunites are composed exclusively of olivine, minor amounts of subhedral, dark brown Cr-spinel, serpentine, metamorphic tremolite, talc and chlorite. The rocks show secondary textures of mesh, poikiloblastic, nematoblastic and jack-straw textures, but original granublastic and porphyroclastic textures are well preserved. Pyroxenes show kink bands, warped cleavages, and undulatory extinction related to metamorphic condition of upper mantle. Petrographical features indicate that a metamorphism at amphibolite facies occurred after serpentinization and chloritization of the Darreh Deh peridotites. Chrysotile cut the primary phases of olivine and pyroxene, but not the metamorphic phases of olivine neoblasts, tremolite, talc and chlorite. Some chlorite crosscut the serpentine veins, and some are in the rim of Cr-spinel and clinopyroxenes. They are mostly replaced by tremolite. Metamorphic olivines have recrystallized as fine-grained neoblasts with lower CaO content (in comparison with the primary and replacive olivines), because they have been formed at the expense of Ca-free mineral of serpentine. Tremolite were produced after chrysotile, talc, and chlorite, wherever enough Ca2+ ions were released from the associated olivine and/or orthopyroxene by serpentinization. Discussion Petrographical and geochemical studies indicate a greenschist-facies stage (serpentinization and chloritization) followed and overprinted by amphibolite-facies metamorphism. The regional metamorphism is verified by the formation of antigorite after lizardite and chrysotile, metamorphic olivine neoblasts after serpentines, chlorite after Cr-spinel, talc after olivine and orthopyroxene, and tremolite after pyroxene, talc, serpentine, and chlorite. The metamorphism imprints on harzburgite and dunite indicate that metamorphism has occurred after melt-rock reactions. Acknowledgment The authors appreciate Prof. Shoji Arai for providing geochemical facilities. References Ghasemi, A. and Talbot, C.J., 2006. A new tectonic scenario for the Sanandaj-Sirjan Zone (Iran). Journal of Asian Earth Science, 26(6): 683-693. Ghazi, J.M., Moazzen, M., Rahgoshay, M. and Shafaii Moghadam, H., 2010. Mineral chemical composition and geodynamic significance of peridotites from Nain ophiolite, Central Iran. Journal of Geodynamics, 49(5): 261-270. Shirdashtzadeh, N., Torabi, G. and Arai, S., 2010. Metamorphism and metasomatism in the Jurassic of Nain ophiolitic mélange, Central Iran. Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen, 255(3): 255–275. Shirdashtzadeh, N., Torabi, G., Meisel, T., Arai, S., Bokhari, S.N.H., Samadi, R. and Gazel, E., 2014a. Origin and evolution of metamorphosed mantle peridotites of Darreh Deh (Nain Ophiolite, Central Iran): Implications for the Eastern Neo-Tethys evolution. Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen, 273(1): 89–120. Shirdashtzadeh, N., Torabi, G. and Samadi, R., 2014b. Geochemistry of pillow lavas and their clinopyroxene: ophiolitic mélanges of Nain and Ashin (Northeast of Isfahan Province). Journal of Economic Geology, 6(1): 49-70. (in Persian with English abstract)

93-115

Authors: Habib Biabangard, Mohammad Boomeri, Khosro Taimouri and Fatemeh Mohammadpour

Introduction Iron mineralization in Roshtkhar is located in 48 Km east of the city of Roshtkhar and south of the Khorasan Razavi province. It is geologically located in the north east of the Lut block and the Khaf-Bardeskan volcano-plutonic belt. The Khaf-Bardeskan belt is an important metallogenic province since it is a host of valuable ore deposits such as the Kuh-e-Zar Au-Spicularite, the Tanourcheh and the Khaf Iron ore deposits (Karimpour and Malekzadeh Shafaroudi, 2007). Iron and Copper mineralization in this belt are known as the hydrothermal, skarn and IOCG types (Karimpour and Malekzadeh Shafaroudi, 2007). IOCG deposits are a new type of magmatic to hydrothermal mineralization in the continental crust (Hitzman et al., 1992). Precambrian marble, Lower Paleozoic schist and metavolcanics are the oldest rocks of the area. The younger units are Oligocene conglomerate, shale and sandstone, Miocene marl and Quaternary deposits. Iron oxides and Cu sulfides are associated with igneous rocks. Fe and Cu mineralization in Roshtkhar has been subject of a few studies such as Yousefi Surani (2006). This study describes the petrography of the host rocks, ore paragenesis, alteration types, geochemistry, genesis and other features of the Fe and Cu mineralization in the Roshtkhar iron. Methods After detailed field studies and sampling, 30 thin sections and 20 polished sections that were prepared from host rocks and ores were studied by conventional petrographic and mineraloghraphic methods in the geology department of the University of Sistan and Baluchestan. 5 samples from the alteration zones were examined by XRD in the Yamagata University in Japan, and 8 samples from the less altered ones were analyzed by XRF and ICP-OES in the Kharazmi University and the Iranian mineral processing research center (IMPRC) in Karaj, respectively. The XRF and ICP-OES data are presented in Table 1. Result and discussion The host rocks of the Roshtkhar Iron deposit are diorite, diorite porphyry, monzosyenitie porphyry, andesite, basalt and lithic tuff in composition and granular, porphyry, microlitic porphyry and hyalomicrolitic in texture and they consist of plagioclase, K-feldspar, amphibole and pyroxene as main primary minerals. These minerals in altered rocks were replaced by phylosilicates, epidote, carbonates and opaque minerals. There are the following alteration zones in the study area: propylitic, sericitic-propylitic, argillic and silicic. The propylitic alteration is characterized by chlorite and calcite as the dominant hydrothermal minerals and little quartz, sericite, kaolinite, and biotite. Hematie and magnetite occur as the main opaque mineral in this alteration zone. Since the proportion of sericite is relatively high in some parts of this zone, it can be named the propylitic-sericitic alteration zone. The argillic alteration zone occurs intensively in the syenite and it is characterized by clay minerals. The silicic alteration occurs as veinlets, silicic breccias, and other open space fillings and it is characterized by dominant quartz. In this study, we use a simple variation of the Gresens method. This method was redescribed by Grant (2005). The samples that were analyzed are dioritic rocks as less altered rocks, altered rocks and mineralized rocks. Samples from the propylitic-sericitic alteration zone relative to less-altered diorite show enrichment in Cl, Ho, Cr, Nd, Ta, Tb, Er, La, Cs, Cu, Zn, Dy, and Fe and depletion in Na2O, K2O, P2O5, Ba, S, Sr, Ce, Sn, Co, Sm, Mo, Ga, Zr, Th, Ni, Nb, Rb, Yb. Hypogene mineralization in Rhoshtkhar is of two types, i.e. oxide and sulfide mineralization. Oxide mineralization occurs as massive veins mainly in the intrusive rocks and it has been controlled by a fault between the dioritic unit and the diorite porphyry and monzosyenite, and it is characterized by spicularitic hematite and magnetite. The sulfide mineralization mainly occurs as silicic veins and veinlets and it is characterized by pyrite and chalcopyrite. Both of these two types were affected by supergene processes and iron hydroxides (goethite and limonite) and Cu carbonates (malachite and azurite) were formed as a result. The gangue minerals are mainly calcite, quartz and clay minerals. The common textures of the hypogene mineralization are mainly open space filling that are characterized by crustification, layered, geode and vug infill, cockade and comb structures. The supergene mineralization is characterized by both open space filling and replacement textures. Based on ore microscopic studies, the iron oxide minerals of hematite and magnetite were mainly formed earlier than the sulfide minerals of chalcopyrite and pyrite. The hypogene vein deposits such as those of the city of Roshtkhar are mainly formed by hydrothermal fluids. The ore minerals in the veins and breccias are deposited as a result of simple cooling, depressurization, fluid mixing, boiling and chemical barriers. The Fe and Cu mineralization in Roshtkhar is genetically related to the hydrothermal fluids that were derived from the magma during emplacement of the intrusive rocks. It seems that the spicularitic hematite is a hypogene early phase indicating the oxygen fugacity of formation environment was high. In the lower fO2, magnetite was replaced by hematite and chalcopyrite and pyrite were probably deposited from hydrothermal fluids as a result of a decrease in fO2, temperature or pH and increase of fS2. The Cu carbonates, secondary sulfides and iron hydroxides were formed by oxidation of the primary sulfides and iron oxides in supergene stage. References Grant, J.A. 2005. Isocon analysis: A brief review of the method and applications. Physics and Chemistry of the Earth, 30(50): 997-1004. Hitzman, M.M., Orekes, N. and Einaudi, M.T. 1992. Geological characteristics and tectonic setting of Proterozoic iron oxide (Cu-Au-LEE) deposits. Precambrian Research, 58(8): 241-287. Karimpour, M.H. and Malekzadeh Shafaroudi, A. 2007. Geochemistry and mineralization Skarn zones and petrology of source rock Sangan Iron deposit Razavi Khorasan. Earth sciences, 65(17):108-124. Yusefi Sourani, L., 2006. Exploration of 1/100,000 Dolatabad map with geological river sediment geophysical data and interpretation of satellite images. M.Sc. Thesis, Ferdowsi University of Mashhad, Mashhad, Iran. 212 pp

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Authors: Arezoo Moradi, Nahid Shabanian Boroujeni and Ali Reza Davoudian Dehkordy

Introduction Studied mylonitic granite-gneiss body is located in the Northwest of the Azna region in the Lorestan province close to the June dimension stone mine. It is a part of the metamorphic- magmatic complex including granite-gneiss, amphibolite, marble and schist. The crystalline basement is attributed to late-Neoproterozoic and it indicates a Panafrican basement, which yields a laser-ablation ICP–MS U–Pb zircon ages of 608 ± 18 Ma and 588 ± 41 Ma (Shakerardakani et al., 2015). There are two granite-gneiss plutons in the complex that are Galeh– Dezh (Shabanian et al., 2009), and June plutons. The Galeh-Doz pluton are previously proposed as syn-deformation pluton with a major S-shaped bend which has been imparted during dextral shearing with a Late Cretaceous (Mohajjel and Fergusson, 2000). However, new age dating on the pluton using U–Pb in the magmatic zircon produced the late-Neoproterozoic dates (Nutman et al., 2014; Shakerardakani et al., 2015). The granite-gneiss plutons show mylonitic fabrics and microstructures (Shabanian et al., 2010). The geochemical characteristics of mylonitic granite-gneiss body near June mine in NW Azna, is in the focus of our research. Materials and methods Petrographic investigations of 30 thin sections were made. Then eight samples were selected and analyzed for whole rock major, trace and REE compositions by ICP-emission spectrometry and ICP-mass spectrometry using natural rock standards as reference samples for calibration at the ACME Analytical Laboratories in Vancouver, British Columbia, Canada. Results The studied gneiss- granitic body has lepido-granoblastic texture as its major texture. It variably shows evidence of dynamic deformation from ultramylonite to protomylonite. The gneiss- granite consists of quartz, alkali feldspar (mostly as perthite), plagioclase, biotite, white mica (muscovite and phengitic muscovite). Accessory phases in the granitoid include, tourmaline, zircon, magmatic epidote, allanite, apatite, and magnetite. The mylonitic gneiss-granite has a mantled porphyroclast texture that may be characterized by large asymmetrical porphyroclasts of K-feldspar and plagioclase with a mantle which includes white-mica, biotite, quartz and feldspar aggregates. Some of the petrographic evidence show dynamic deformation during the crystallization such as grain boundary migration (GBM) or sub-grain rotation (SGR), patchy perthite. Evidence of strain, such as deformation twins, bent or curved twins, undulatory extinction occur characteristically in plagioclase and display dynamic deformation in solid state. The rocks exhibit identical compositional ranges with 71.24–78.35 wt.% SiO2; high levels of alkalies (Na2O ranges from 3.07 to 4.02 %, K2O varies from 4.18 to 5.53 %); low levels of Fe2O3tot (0.80 to 2.60 %). Also, the trace element compositions display significant variations, such as Zr (157.7-330.5 ppm), Eu (0.07-0.28 ppm), Nb (40.9-77.3 ppm), Ga (19.7-25.97 ppm). The studied rocks are strongly enriched in LREE and HFSE and show a strong depletion in Ba, Sr, Eu and Ti and enrichment in Rb and Zr. The element contents are also similar to typical A-type granite (Whalen et al., 1987). The rocks are alkali to alkali-calcic, metaluminous to mildly peraluminous granite and ferroan in new geochemical classification scheme for granitoids (proposed by Frost et al., 2001). Discussion The chondrite-normalized rare-earth element patterns of the mylonitic gneiss- granitic rocks indicate the LREE over HREE fractionation with significant negative Eu anomalies. Primitive-mantle-normalized spidergrams (Sun and McDonough, 1989) normalized trace element patterns with negative Ba and Nb anomalies, and positive Rb, Th and Ce anomalies, simulate the collisional and post-collisional granitoids of Pearce et al (Pearce et al., 1984). All of the samples fall in the A2 group in Eby classification (Eby, 1992). On the tectonic discrimination plots, the granites show a within-plate granite (WPG) character (Pearce et al., 1984). Acknowledgements The study was completed at the Shahrekord University and it was supported by the office of graduate studies. The authors are grateful to the office for their support. References Eby, G.N., 1992. Chemical subdivision of the A-type granitoids: petrogenetic and tectonic implications. Chemical Geology, 20(7): 641–644. Mohajjel, M. and Fergusson, C.L., 2000. Dextral transpression in Late Cretaceous continental collision, Sanandaj–Sirjan Zone, western Iran. Journal of Structural Geology, 22(8): 1125-1139. Nutman, A.P., Mohajjel, M., Bennett, V.C. and Fergusson, C.L., 2014. Gondwanan Eoarchean Neoproterozoic ancient crustal material in Iran and Turkey: zircon U–Pb–Hf isotopic evidence1. Canadian Journal of Earth Sciences, 51(3): 272–285. Pearce, J.A., Harris, N.W. and Tindle, A.G., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology, 25(4): 956–983. Shabanian, N., Davoudian, A.R., Khalili, M. and Khodami, M., 2010. Texture evidences imply on dynamic conditions in late-stage to post magmatic crystallization from dynamo-magmatic gnessies of Ghaleh-Dezh, Azna. Iranian Society of Crystallography and Mineralogy, 18(3): 463-472. (in Persian with English abstract) Shabanian, N., Khalili, M., Davoudian, A.R. and Mohajjel, M., 2009. Petrography and geochemistry of mylonitic granite from Ghaleh-Dezh, NW Azna, Sanandaj-Sirjan Zone, Iran. Neues Jahrbuch Fur Mineralogie-Abhandlungen, 185(3): 233-248. Shakerardakani, F., Neubauer, F., Masoudi, F., Mehrabi, B., Liu, X., Dong, Y., Mohajjel, M., Monfaredi, B. and Friedl, G., 2015. Panafrican basement and Mesozoic gabbro in the Zagros orogenic belt in the Dorud–Azna region (NWIran): Laser-ablation ICP–MS zircon ages and geochemistry. Tectonophysics, 647–648: 146–171. Sun, S.S. and McDonough, W.E., 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: A.D. Saunders and M.J. Norry (Editor), Magmatism in the Ocean Basins. Geological Society 42, London, pp. 313–345. Whalen, J.B., Currie, K.L. and Chappell, B.W., 1987. A-type granites: geochemical characteristics, discrimination and petrogenesis. Contributions to Mineralogy and Petrology, 95(4): 407–419.

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Authors: Jamal Rasouli, Mansour Ghorbani and Vahid Ahadnejad

Introduction The Jebale-Barez Plutonic Complex (JBPC) is composed of many intrusive bodies and is located in the southeastern province of Kerman on the longitude of the 57◦ 45 ' east to 58◦ 00' and Northern latitudes 28◦ 30' to 29◦ 00'. The petrologic composition is composed of granodiorite, quartzdiorite, granite, alkali-granite, and trace amounts of tonalite with dominant granodiorite composition. Previously, the JBPC was separated into three plutonic phases by Ghorbani (2014). The first plutonic phase is the main body of the complex with composition of quartz-diorite to granodiorite. After differentiation of magma in the magmatic chamber, the porphyritic and not fully consolidated magmas have intruded into the main body. Their compositions were dominantly granodiorite and granite that are defined as the second plutonic phase. Finally, the last phase was started by an intrusion of the holo- leucogranite into the previous bodies. This plutonic activity was pursued by the minor Quaternary basaltic volcanism that shows metamorphic haloes in the contacts. They are dominantly porphyric leucogranites. However, some bodies show dendritic texture that may imply the existence of silicic fluids in the latest crystallization stages. Materials and methods In this article different analysis methods were used. For example, we used a total of two hundred samples of the various granitoids that were selected for common thin section study. Forty four representative samples from the different granitic rocks were selected for whole rock chemical analyses. The analyses of both major and trace elements were performed at the Department of Earth Sciences, the University of Perugia, Italy. The analysis for all major elements was carried out by an X-ray fluorescence spectrometry (XRF) using a tube completed with a Rn and W anode under conditions with acceleration voltage of 40-45 kV and electric current ranging from I=30-35 mA. After calcination of powdered samples and full matrix correction, the sum of all major oxides was equal to about 100 wt.%. The concentration of trace elements in the selected samples has been performed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The uncertainty is <10% for trace element contents higher than 2 ppm (except for Pb, <15%) and <15% for all the other trace elements. Results The microstructures observed in thin sections in this study were grouped into three types: (i) magmatic microstructures; (ii) submagmatic microstructures and (iii) mylonitic microstructures. Magmatic and submagmatic microstructures occurred simultaneously with the emplacement of granitoid complex and mylonitic microstructures that occurred after emplacement of granitoid complex. The magma nature of these rocks is sub-alkaline-(calc-alkaline), which fall into calc-alkaline series with high potassium in SiO2-K2O plots. The geochemical variation diagrams of major oxides, the continuous spectrum of rock compositions has been carried out which indicates the crystallization of magmatic differentiation and extensive appendices. Field observations, petrographic and geochemical studies suggest that the rocks in this area have type I and CAG subsections. Studying the geochemical diagrams of the rocks in the studied area indicates that these rocks have been formed in active continental margin tectononic settings. It seems that the Jebale-Barez granitoid Complex is located within a shear zone. Magma has been percolated through Mijan caldera and emplacement Forms of Sill along the shear zone during various periods and the structural setting of granitoid complex in the Jebale-Barez is extensional-shear fractures which are the product of transpression tectonic regime. Discussion The JBPC is calc-alkaline, high-K, subalkaline, and mostly metaluminous except granite and alkali-granite units which are slightly peraluminous and I type in character. These geochemical properties of the studied granitoids suggest subduction-related arc magmatism. The systematic variation for the major elements implies involvement of fractional crystallization in the evolution of JBPC. The trends are consistent with the fractionation of plagioclase feldspar and ferromagnesian minerals as indicated by decreasing MgO, CaO, FeOt and TiO2 with increasing SiO2 despie the content of (K2O+Na2O). It generally increases with increasing SiO2 for intermediate compositions (67 wt% SiO2 ≤) and then decreases for more felsic granitic rocks, indicating that sodic feldspar was a major fractionating phase for alkali-granite and granite suit (Rasouli, 2015). Overall REE abundances slightly decrease with increasing SiO2 consistent with plagioclase fractionation. The distribution of voluminous volcanic rocks in the studied area implies that the JBPC could be a part of the mature magmatic arc. The field petrography and geochemical studies indicated that the JPBC originated from both crustal and mantle derived magmas: The increase in temperature and excess fluid pressure caused by subduction trigged melting of mantle edge and formation of basaltic magma and its ascending and introducing into the crust was followed by partial melting (Rasouli, 2015). The juxtaposed series of mafic-felsic pulses formed a mixed magma. Finally this magma is emplaced at broad, shallow magma chamber (9-12 km), where the differentiation took place by fractional crystallization and produced a wide variety of rocks form quartz-diorite to alkali granite. In such shallow magma reservoirs, the emplacement of magma took place as sill (Fridrich et al, 1991). Combining field observations and petrofabric studies displayed a deep caldera as a feeder zone for Eocene volcanic rocks (Rasouli, 2015). The JBPC is located in a shear zone and multiple magmatic pulses were injected as sills. The magmatic fabrics show active tectonic controls on magmatism during and after magma emplacement. The transpressional tectonic regime is well compatible with our data. References Fridrich, C.J., Smith, R.P., DeWitt, E. and McKee, E.H., 1991. Structural, eruptive, and intrusive evolution of the Grizzly Peak caldera, Sawatch Range, Colorado. Geological Society of America Bulletin, 103(2): 1160–1177. Ghorbani, M., 2014. Geology of Iran. Aryan Zamin, Tehran, 479 pp. Rasouli, J., 2015. Petrology and geochemistry of Jabal Barez granitoid batholith with a view to the zoning alteration and copper mineralization (North East Jiroft). Ph.D. Thesis, Shahid Beheshti University, Tehran, Iran, 369 pp.

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Authors: Majid Tashi, Fardin Mousivand and Habibollah Ghasemi

Introduction Iran hosts numerous types of Volcanogenic massive sulfide (VMS) deposits that occur within different tectonic assemblages and have formed at discrete time periods (Mousivand et al. 2008). The Sabzevar zone hosts several VMS deposits including the Nudeh Cu-Ag deposit (Maghfouri, 2012) and some deposits in the Kharturan area (Tashi et al., 2014), and the Kharturan area locates in the Sabzevar subzone of the Central East Iranian Microcontinent. The Sabzevar subzone mainly involves Mesozoic and Cenozoic rock unites. The Late Cretaceous ophiolite mellanges and volcano-sedimentary sequences have high extension in the Subzone. Based on Rossetti (Rossetti et al. 2010), the Cretaceous rock units were formed in a back-arc setting due to subduction of the Neo-Tethyan oceanic crust beneath the Iranian plate. The exposed rock units of the Kharturan area from bottom to top are dominated by Early Cretaceous, orbitolina-bearing massive limestone, dacitic-andesitic volcanics and related volcaniclastic rocks٫ chert and radiolarite and Late Cretaceous globotrunkana- bearing limestone, paleocene polygenic conglomerate consisting of the Cretaceous volcanics and limestone pebbles (equal to the Kerman conglomerate), and Pliocene weakly-cemented polygenic conglomerate horizon. The Garmabe Paein copper-silver deposit and the Asbkeshan deposit and a few occurrences, are located at 290 km southeast of Shahrood and they have occurred within the Upper Cretaceous volcano-sedimentary sequence in the Sabzevar subzone. The aim of this study is to discuss the genesis of the Garmabe Paein deposit based on geological, textural and structural, mineralogical and geochemical evidence. Materials and methods A field study and sampling was performed during the year 2013. During the field observations, 94 rock samples were collected from the study area, and 45 thin sections were prepared and studied using a polarizing microscope. Also, 5 samples for the XRD method, 21 samples for the XRF and ICP-OES methods were analyzed in the Iranian Mines and Mining Industries Development and Renovation (IMIDRO) Company labs. Results The Garmabe Paein copper-silver deposit is located in the Sabzevar subzone of the Late Cretaceous Volcanio-sedimentary sequence. This mineralization occurred as stratiform and stratabound in a specific stratigraphic horizon. The host rocks of mineralization are andesitic-dacitic volcanic rocks and their related volcaniclastics. The mineralization occurred as four ore facies, from footwall to hanging wall: vein-veinlet-s (stringer), massive, bedded and exhalites. Ore textures and structures involve massive, semi-massive, laminated, banded, vein-veinlets, replacement and open space fillings. Minerlogically, the deposit contains primary minerals such as pyrite, chalcopyrite and magnetite, and secondary minerals such as native copper, cuprite, covellite, malachite and Fe-Mn oxides. Wallrock alterations are dominated by chloritic and minor siliceous and argillic. The highest grades of gold and silver in the deposit are 1 and 19 grams per ton, respectively. The amounts of Zn, Pb, Au, As, Ag and Mn increase from the stringer to the upper part of the deposit. It seems that the occurrence of submarine volcanic activity in the Late Cretaceous back- arc basin have resulted in the deposition of this Besshi type massive sulfide deposit. Discussion Most of characteristics of the Garmabe Paein Cu-Ag deposit including tectonic setting, geological environment, host rocks, geometry, textural and structural, mineralogical and geochemical features, are very similar to those of the Besshi- or pelitic mafic-type (Franklin et al., 2005) volcanogenic massive sulfide (VMS) deposits. Acknowledgements The authors are grateful to the University of Shahrood Grant Commission for research funding and the IMIDRO Company. References Franklin, J.M., Gibson, H.L., Galley, A.G. and Jonasson, I.R., 2005. Volcanogenic massive sulfide deposits. In: J.W. Hedenquist, J.F.H. Thompson, R.J. Goldfarb and J.P. Richads (Editors), Economic Geology 100th Anniversary Volume. Society of Economic Geologists, Littleton, Colorado, pp.523-560. Maghfouri, S., 2012. Geology, mineralogy, geochemistry and genesis of Cu mineralization Within Late Cretaceous Volcano- sedimentary sequence in southwest of Sabzevar, with emphasis on the Nudeh deposit. M.Sc. Thesis, Tarbit Modares University, Tehran, Iran, 312 pp. (In Persian with English abstract) Mousivand, F., Rastad, E. and Peter, J.M., 2008. An overview of volcanogenic massive sulfide deposits of Iran. 33rd International Geology Congress Oslo, Oslo, Norway. Rossetti, F., Nasrabady, M., Vignaroli, G., Theye, T., Gerdes, A., Razavi, M. and MoinVaziri, H., 2010. Early Cretaceous migmatitic mafic granulites from the Sabzevar range (NE Iran): implications for the closure of the Mesozoic peri- Tethyan oceans in central Iran. Journal of Terra Nova, 22(1): 26-34. Tashi, M., Mousivand, F. and Ghasemi, H., 2014. Volcanogenic massive sulfide Cu-Ag mineralization in the Kharturan area, southeast of Shahrood. 1th International Workshop on Tethyan Orogenesis and Metallogeny in Asia and Silk Road Higher Education Cooperation Forum, China University of Geosciences (Wuhan), Wuhan, China.

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Authors: Amin Hossein Morshedy, Amir Hossein Kouhsari and Mohammad Reza Shakery Varzaneh

Introduction Nowadays, exploration of rare earth element (REE) resources is considered as one of the strategic priorities, which has a special position in the advanced and intelligent industries (Castor and Hedrick, 2006). Significant resources of REEs are found in a wide range of geological settings, including primary deposits associated with igneous and hydrothermal processes (e.g. carbonatite, (per) alkaline-igneous rocks, iron-oxide breccia complexes, scarns, fluorapatite veins and pegmatites), and secondary deposits concentrated by sedimentary processes and weathering (e.g. heavy-mineral sand deposits, fluviatile sandstones, unconformity-related uranium deposits, and lignites) (Jaireth et al., 2014). Recent studies on various parts of Iran led to the identification of promising potential of these elements, including Central Iran, alkaline rocks in the Eslami Peninsula, iron and apatite in the Hormuz Island, Kahnouj titanium deposit, granitoid bodies in Yazd, Azerbaijan, and Mashhad and associated dikes, and finally placers related to the Shemshak formation in Marvast, Kharanagh, and Ardekan indicate high concentration of REE in magmatogenic iron–apatite deposits in Central Iran and placers in Marvast area in Yazd (Ghorbani, 2013). Materials and methods In the present study, the geochemical behavior of rare earth elements is modeled by using multivariate statistical methods in the eastern part of the Marvast placer. Marvast is located 185 km south of the city of Yazd in central Iran between Yazd and Mehriz. This area lies within the southeastern part of the Sanandaj-Sirjan Zone (Alipour-Asll et al., 2012). The samples of 53 wells were analyzed for Whole-rock trace-element concentrations (including REE) by inductively coupled plasma-mass spectrometry (ICP-MS) (GSI, 2004). The clustering techniques such as multivariate statistical analysis technique can be employed to find appropriate groups in data sets. One of the main objectives of data clustering is to maximize both the similarity within each cluster and the difference between clusters, and finally find the structure in the data. Nowadays, cluster analysis is applied in many disciplines: biology, botany, medicine, psychology, geography, marketing, image processing, psychiatry, archaeology, etc. (Everitt et al., 2011). To execute a partitioning algorithm, the principal components analysis (PCA) algorithm is applied for feature selection, feature extraction and dimension reduction. Hierarchical clustering can be utilized to provide a nested sequence of partitions with bottom-up or top-down methods based on similarity. The single linkage and complete linkage are the most popular hierarchical algorithms (Jain et al., 1999; Ji et al., 2007). Results and discussion The REE chondrite-normalized pattern for the eastern area in the Marvast placer represents a high match to the standard pattern of monazite. This pattern shows the positive anomaly of Ce and the negative anomaly of Eu. To determine the distribution of REEs concentration, 2D interpolation maps were plotted in three groups of light, middle, and heavy REEs (LREE, MREE, and HREE), which were indicated in the geochemical anomaly at the south and south-west of the area. The relative ratios of (LREE/HREE) and (Ce/Eu) exposed the high proportion of LREEs to HREEs. In the next section, the hierarchical clustering algorithm was employed to partition the data in the feature and sample levels. The elements portioning demonstrated four separated groups, which can be related to atomic and chemical structures. The studied region was divided into four zones by the clustering approach. The fourth zone confine coincided with the REE anomaly area. Finally, PCA was applied as the multivariate statistical tool to this dataset. Hence three principal components modeled over 90% of the variance. For the first component, the distribution map of load factor has a good agreement with anomaly area. References Alipour-Asll, M., Mirnejad, H. and Milodowski, A.E., 2012. Occurrence and paragenesis of diagenetic monazite in the upper Triassic black shales of the Marvast region, South Yazd, Iran. Mineralogy and Petrology, 104(3-4): 197-210. Castor, S.B. and Hedrick, J.B., 2006. Rare earth elements. In: J.E. Kogel (Editors), Industrial minerals & rocks: commodities, markets, and uses. Society for mining, metallurgy, and exploration, Inc. (SME), Colorado, pp. 769-792. Everitt, B., Landau, S., Leese, M. and Stahl, D., 2011. Cluster Analysis. 5th ed., Wiley Publishing, Hoboken, Geological Survey of Iran (GSI), 2004. Exploration of rare earth element and monazite in the alluvium of the southern Marvast (eastern area). Tehran, 66 pp. (in Persian) Ghorbani, M., 2013. The economic geology of Iran: mineral deposits and natural resources. Springer, London, 569 pp. Jain, A.K., Murty, M.N. and Flynn, P.J., 1999. Data clustering: a review. Association for Computing Machinery computing surveys, 31(3): 264-323. Jaireth, S., Hoatson D.M. and Miezitis Y., 2014. Geological setting and resources of the major rare-earth-element deposits in Australia. Ore Geology Reviews, 62: 72-128. Ji, H., Zeng, D., Shi, Y., Wu, Y. and Wu, X., 2007. Semi-hierarchical correspondence cluster analysis and regional geochemical pattern recognition. Journal of Geochemical Exploration, 93(2): 109-119.

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Authors: Salimeh Sadat Komeili; Mahmoud Khalili; Hooshang Asadi Haroni; Hashem Bagheri; Farimah Ayati

Introduction The Kahang Cu- Mo deposit is situated approximately 73 Km northeast of Isfahan. Asadi (2007) identified a geological reserve of 40 Mt (proven reserve) grading at 0.53 Cu, 0.02 Mo and estimated reserve of 120 Mt. All the rock types in the region have been subjected to hydrothermal solutions which gave rise to three different alteration facies. The dacite and rhyodacite volcanic rocks and granitic- granodioritic stocks have experienced phyllic alteration. Disseminated and stockwork siliceous veins are the major styles of mineralization in this zone. Intermediate argillitic alteration developed on a part of dacitic and rhyodacitic rocks whereas andesite and basaltic-andesite plus related pyroclastic rocks have been subjected to propyllitic alteration. This paper presents the results of geological and mineralogical studies carried out in the Kahang area. This preliminary information is integrated with additional data on ore mineralogy, fluid inclusions and stable isotopes in view of understanding the genesis of the Cu- Mo deposit and the nature of the fluids involved in ore formation. Materials and Methods A total of 18 polished thin sections were prepared at the University of Isfahan for optical study. Fluid inclusions study was carried out on 8 double polished quartz thin sections (stockworks containing ore mineralization from phyllic zone). H – O stable isotope analysis was performed on 4 quartz samples from siliceous stockworks (from phyllic altered zone) and one vein epidote sample (from propyllitic zone). All isotopic analyses were performed at the University of Oregan, Oregan, USA. Discussion In the investigated mineralization area, the hypogene zone is characterized by the presence of pyrite, chalcopyrite, bornite and magnetite. Hematite, goethite, jarosite, malachite and azurite are the predominant minerals of supergene zone. The major textures of the primary sulfides are disseminated, vein and veinlet. Pyrite is the most common hypogene sulfide mineral and chalcopyrite is the predominant Cu- sulfide in the Kahang mineralized area. Primary magnetite grains having irregular boundaries formed in association with phyllic –potassic altered zones (Afshooni et al., 2014). Chalcocite and covellite as secondary copper minerals in the enriched supergene zone replaced the chalcopyrite. Thermometric studies on fluid inclusions conducted on quartz veins was related to the phyllic zone. Almost all studied fluid inclusions were homogenized to the liquid phase. Hydrothermal solutions with salinity over 26% wt equivalent NaCl, comparable with those of the other porphyry deposits (Morales Ruano et al., 2002; Hezarkhani, 2006; Hezarkhani, 2009) were responsible for the formation of the Kahang porphyry copper deposit. Homogenization temperatures of 200-450°C and 500-550°C were obtained from heating- cooling experiments on the two and multi phase fluid inclusions. The presence of gas riched fluid inclusions together with those of liquid riched and multiphase different salinities in the quartz veins as well as the occurrence of hydrothermal breccias are indicative of boiling fluids. Result In the Kahang porphyry Cu- deposit, the oxidation zone is characterized by hematite, goethite, jarosite, malachite, and azurite; the supergene zone is identified by chalcocite, chalcopyrite and coevllite; and chalcopyrite, pyrite and magnetite are the mineral assemblage of the hypogene zone. The volcanic as well as the plutonic rocks of the area have been hydrothermally altered which gave rise to the formation of propyllitic, intermediate argillic and mineralized phyllic zones. Fluid inclusion study on quartz veins revealed salinity over 26% wt equivalent NaCl and homogenization temperature of 200-450°C and 500-550°C. The presence of gas riched fluid inclusions together with those of liquid riched and multiphase different salinities in the quartz veins as well as the occurrence of hydrothermal breccias are indicative of boiling event, owing to the pressure reduction in the faulted zones and mineralized hydrothermal breccias and/or increase of hydrostatic pressure compared to the lithostatic pressure. This may be caused by the instability of the copper complex accompanied by precipitation of copper. The decrease of temperature and the diluted mineralized fluids could be the cause of precipitation of copper due to mixing with the meteoric water. Stable isotope study supports the mixing of magmatic and meteoric waters in the peripheral zones of ore deposit (phyllic and propyllitic zones). Acknowledgements This paper has benefited from critical comments by Dr. Shamsi pour and Dr. Mackizadeh who are thanked for their interest. Financial support of the University of Isfahan is acknowledged. References Afshooni, S.Z., Esmaeily, D. and Asadi Haroni, H., 2014. Stable isotopes (S, H, O) study In phyllic and potassic- phyllic alteration zones of the Kahang porphyry copper- Molybdenum deposit (Northeast of Isfahan). Journal of Advanced Applied Geology, 1(7): 64-73. (in Persian) Asadi, H., 2007. Detailed exploration in Kahang porphyry Cu- Mo index. Dorsa pardazeh company, Isfahan, Report 3, 114 pp. (in Persian) Hezarkhani, A., 2006. Hydrothermal evolution of the Sar-Cheshmeh porphyry Cu-Mo deposit, Iran: Evidence from fluid inclusions. Journal of Asian Earth Sciences, 28(4-6): 409-422. Hezarkhani, A., 2009. Hydrothermal fluid geochemistry at the Chah-Firuzeh porphyry copper deposit, Iran: Evidence from fluid inclusions. Journal of Geochemical Exploration, 101(3): 254-264. Morales Ruano, S., Both, R.A. and Golding, S.D., 2002. A fluid inclusion and stable isotope study of the Moonta copper-gold deposits, South Australia: evidence for fluid immiscibility in a magmatic hydrothermal system. Chemical Geology, 192(3-4): 211-226.

325-342

Authors: Seyed Reza Mehrnia

Introduction Tekieh Lead-Zinc ore deposit that is located in the Sanandaj-Sirjan structural zone has been recognized as one of the most important mineralized regions in Malayer-Isfahan metallogenic sub-state, south east of Arak (Momenzadeh and Ziseman, 1981). Carbonate host units have been developed along (or across) the Vishan-Tekieh anticline as the main structure extended in NW-SE trends (Annells et al, 1985). According to geochemical investigations (Salehi, 2004), the element content of the mineralized regions has originated from Alpine post-volcanisms and subsequently it has migrated toward early Cretaceous formations (dolomitic limestones) among several hypogenic stages (Torkashvand et al., 2009). Also echelon type structures consisting of folded systems and inversed faulting of structures are the most common features in western and eastern parts of ore deposit regions (Annells et al, 1985). Syngenetic enrichments beside limited (rarely developed) epigenetic mineralization have been known as two main phases which are closely relevant to ore forming processes in the massive lenses and vein type occurrences, respectively (Momenzadeh and Ziseman, 1981). Material and Methods In this research, two statistical techniques that consist of classical and fractal equations (Mandelbrot, 2005) were applied in geochemical (Torkashvand et al., 2009) and geophysical (Jafari, 2007) databases for obtaining the linear and nonlinear distributions of geochemical elements (Tekieh Pb-Zn content) in association with resistivity variations and induction polarization measurements (Calagari, 2010). According to linear statistical techniques (Torkashvand et al., 2009), the main central parameters such as mean, median and mode in addition to variances and standard deviations as distribution tendencies could be used for obtaining the regression coefficients of the databases. However, in fractal statistics, a reliable regression between geoelectrical - geochemical anomalies should be calculated based on measuring the fractal dimensional variations in the recursive patterns (Mehrnia, 2013). In practice, the Area-Concentration equations (Mandelbrot, 2005) were applied in resistivity, induction polarization, Pb and Zn datasets for achieving the nonlinear relationships in anomalous regions which were characterized by increasing in regression coefficients with more spatial correlation of the variable than linear statistics (Mehrnia, 2013). Results and Discussion This research showed that both linear and nonlinear statistics are able to estimate the spatial association of geochemical anomalies with geophysical variables. A meaningful increase in the regression coefficient was also revealed after measuring the self-similar peculiarities of concentration values on gridded plots (Salehi, 2004; Torkashvand et al., 2009). From the fractal point of view, Pb ore-minerals have been deposited in the western sub-region, while Zn mineralization seems to be extended in the depth of eastern alterations. Also a predictable geochemical zonation can be considered in the western target (meaningful Pb anomalies) that is more patterned than the eastern halos according to geological observations (Momenzadeh and Ziseman, 1981) and mineralogical evidences (Salehi, 2004). An increase in Supra ore/Sub ore proportional content was measured in the western sub-region which indicated more reliable potential of Pb mineralization (Galena as a particular indication of sulfide-rich minerals) than the same phases of ore forming processes in the eastern sub-region, although the content of Pb-ores rapidly decreases in the eastern target and is replaced by Zn minerals (Sphalerite as particular indication of sulfide-rich mineralization). Because power law relationships are significant in both geochemical and geophysical anomalies (Mehrnia, 2013) a detailed program including borehole geophysics and litho-geochemical land-surveys should be considered in the prospected regions. Therefore, upcoming phases should emphasize on self-organized distribution of Pb-Zn anomalies to introduce a new set of nonlinear distributions in order to find the confidence regression coefficients between the variables. As the final results, fractal analysis of available databases represented new target areas with better mineralization aggregations than linear analysis of the anomalous regions according to micrographs. It means that surficial mineralization processes could be extended in depth and enriched next to altered host units because of a nonlinear but self-organized distribution of geochemical- geophysical anomalies in Tekieh ore deposit region. References Annells, R.N., Arthurton, R.S., Bazley, R.A.B., Davies, R.G., Hamedi, M.A.R. and Rahimzadeh, F.R., 1985. Geological Map of Shazand- Khomein. Scale: 1:100000, Cartographic Department of Geological Survey of Iran. Calagari, A.A., 2010. Principles of geophysical explorations. University of Tabriz, Tabriz, 485 pp. Jafari, H., 2007. Using geoelectrical techniques for Zn-Pb explorations in Haft-Emarat district, Tekieh region (South East of Arak). Kimya Kavan Tosee Novin Company, Tehran, 206 pp. Mandelbrot, B., 2005. Fractal Geometry of Nature. W.H Freeman & Company, New York, 468 pp. Mehrnia, S.R.,2013. Application of fractal geometry for recognizing the pattern of textural zoning in epithermal deposits: Shikhdarabad Au-Cu indices (Eastern Azerbaijan). Journal of Economic Geology, 1(5): 23-36. Momenzadeh, M. and Ziseman, H., 1981. Lead – Zinc re mineralization potentials in Malayer – Esfahan district. Journal of Ore Deposit, 3(1): 88-101. Salehi, L., 2004. Geochemistry of REE content in Tekieh Pb-Zn ore deposit. M.Sc. Thesis, Shahid Beheshti University, Tehran, Iran, 181 pp. Torkashvand, S., Mehrnia, S.R. and Moghaddasi, S.J., 2009. Co-Processing of the geophysical parameters for Tekieh Zn-Pb ore deposits (south east of Arak). 4th PNU Geological National Conference, Payam Noor University of Mashhad, Mashhad, Iran.

359-380

Authors: Mir Ali Asghar Mokhtari; Mohammad Ebrahimi; Mohammad Reza Ghorbani

Introduction The Avan Cu-Fe skarn is located at the southern margin of Qaradagh batholith, about 60 km north of Tabriz. The Skarn-type metasomatic alteration is the result of Qaradagh batholith intrusion into the Upper Cretaceous impure carbonates. The studied area belongs to the Central Iranian structural zone. In regional scale, the studied area is a part of the Zangezour mineralization zone in the Lesser Caucasus. Several studies (Karimzadeh Somarin and Moayed, 2002; Calagari and Hosseinzadeh, 2005; Mokhtari, 2008; Baghban Asgharinezhad, 2012; Mokhtari, 2012) including master’s theses and research programs have been done on some skarns in the Azarbaijan area considering their petrologic and mineralization aspects. However, before this study, the Avan skarn aureole has not been studied in detail. In this paper, various geological aspects of the Avan skarn including mineralogy, bi-metasomatic alteration, metasomatism and mineralization during the progressive and retrograde stages of the skarnification processes have been studied in detail. Research Method This research consists of field and laboratory studies. Field studies include preparation of the geological map, identifying the relationship between the intrusion and the skarn aureole, identifying the relationship between different parts of the skarn zone and also collecting samples for laboratory studies. Laboratory studies include petrography, mineralography and microprobe studies. Cameca SX100 Microprobe belonging to Geological Survey of the Czech Republic was used in order to determine the chemical composition of the calc-silicate minerals such as pyroxene and garnet in garnet skarn and pyroxene- garnet skarn sub-zones. Discussion and conclusion Qaradagh batholith is composed of discrete acid to mafic phases including gabbro, diorite, quartz diorite, quartz monzonite, quartz monzodiorite, tonalite, granodiorite, monzogranite and granite porphyry which is dominated by granodiorite-quartz monzonite. Granitoids of this batholith are metaluminus, high K calc-alkaline I-type granite (Mokhtari, 2008). The Avan Cu-Fe skarn is related to the intrusion of granodioritic-quartz monzonitic part of the Qaradagh batholith into the Upper Cretaceous flysch- type rocks consisting of biomicrite, clay limestone, marl, siltstone and mudstone. The Avan skarn consists of three zones of endoskarn, exoskarn and marble. The main Cu-Fe mineralized zone is related to the exoskarn zone, which has 600 meters of length and 50 meters of thickness, respectively. The Exoskarn zone consists of garnet skarn, pyroxene-garnet skarn and ore skarn sub-zones. Garnet, belonging to ugrandite series (Ad53-89) with more than 50 percentage in volume, is the most important anhydrous calc-silicate mineral in the garnet skarn and the pyroxene-garnet skarn sub-zones. Some of the garnet crystals are zoned and their chemical composition changes toward the rim to almost pure andradite (Ad99). Clinopyroxene which has diopsidic composition (Di75-96), is another anhydrous calc-silicate mineral in the exoskarn zone with an abundance that reaches up to 50 percent in volume in pyroxene-garnet skarn sub-zone. The ore skarn sub-zone is located toward the outer part of the exoskarn zone and close to the border of the marble zone. The abundance of ore minerals in this sub-zone reaches up to 50 percentage in volume and includes magnetite, hematite, pyrite, chalcopyrite, bornite, malachite and goethite among which pyrite is the most abundant. In this sub-zone, anhydrous calc-silicate minerals of garnet and clinopyroxene have undergone intensive alteration and are replaced with hydrous calc-silicate (epidote and tremolite- actinolite), oxide (magnetite and hematite) and sulfide (pyrite, chalcopyrite and bornite) minerals. Based on the textural and mineralogical studies, the skarnification processes in the studied area can be categorized into two main stages: 1) prograde and 2) retrograde. During the prograde stage, the heat flow of the granitoid has caused isochemical metamorphism and changing more pure limestones to marble and marlly limestones to skarnoid (metamorphism and bi-metasomatism). The high temperature magmatic fluids have caused prograde metamorphism during which anhydrous calc-silicate minerals including garnet and pyroxene have appeared. During the early retrograde stage, i.e. the mineralization sub-stage, lower temperature hydrothermal fluids have caused hydrolysis and carbonization because of which anhydrous calc-silicate minerals along with their fractures and microfractures are changed to hydrous calc-silicate (epidote and tremolite-actinolite), oxide (magnetite and hematite), sulfide (pyrite, chalcopyrite and bornite) and carbonate (calcite) minerals. During the late retrograde stage, relatively low temperature fluids have altered anhydrous and hydrous calc-silicate mineral assemblage formed during the previous stages into a very fine grained mineral assemblage including clay minerals, chlorite and iron hydroxides. Presence of replacement textures in ore minerals and anhydrous calc-silicate minerals accompanied with open filling textures in the anhydrous calc-silicate minerals, for example oxide and sulphide veinlets within the garnet crystals, indicate that the mentioned ore minerals have been simultaneously generated with hydrous calc-silicate minerals (epidote and tremolite-actinolite) during the early prograde stage. The presence of minor amounts of wollastonite among the mineral assemblage of the Avan skarn, intergrowth of garnet and pyroxene, absence of reaction rim between garnet and clinopyroxene and absence of replacement textures indicate that these minerals have been simultaneously generated within the temperature ranges of 430–600 ºC and ƒO2 > 10-26, respectively. Acknowledgements The authors are grateful to the Journal of Economic Geology reviewers and editors for their constructive suggestions to the manuscript. Reference Baghban Asgharinezhad, S., 2012. Investigation of genesis, mineralogy and geochemistry of Fe-Cu skarn in Astamal area, NE Kharvana, Eastern Azarbaijan. MSc. Thesis, University of Tabriz, Tabriz, Iran, 185 pp. (in Persian with English abstract) Calagari, A.A. and Hosseinzadeh, G., 2005. The mineralogy of copper-bearing skarn to the east of the Sungun-Chay River, East-Azarbaijan, Iran. Journal of Asian Earth Sciences, 28(4-6): 423-438. Karimzadeh Somarin, A. and Moayed, M., 2002. Granite and gabbro-diorite associated skarn deposits of NW Iran. Ore geology reviews, 20(3-4): 127-138. Mokhtari, M.A.A., 2008. Petrology, geochemistry and petrogenesis of Qaradagh batholith (east of Syahrood, Eastern Azarbaijan) and related skarn with considering mineralization. Ph.D. Thesis, Tarbiat Modares University, Tehran, Iran, 347 pp. (in Persian with English abstract) Mokhtari, M.A.A., 2012. The mineralogy and petrology of the Pahnavar Fe skarn, in the Eastern Azarbaijan, NW Iran. Central European Journal of Geosciences, 4(4): 578-591.

399-413

Authors: Maryam Ahankoub; Yoshihiro Asahara

Introduction There are some theories about the Paleotethys event during the Paleozoic that have been proposed by geologists (Metcalfe, 2006). Some scientist offered some pieces of evidence about the northern margin of Gondwana (Zhu et al., 2010). The Paleotethys Ocean and Hercynian orogenic report first in Iran, have been Offered from the Morrow and Misho Mountain (Eftekharnejad, 1981). Misho Mountains is located between the north and south Misho faults and cause the formation of a positive flower structure (Moayyed and Hossainzade, 2011). There is theory about Misho southern fault as the best candidate of the Paleotethys suture zone (Moayyed and Hossainzade, 2011). Geochemistry and Sr –Nd isotopic data of the A2 granitic and Synite rocks of the East Misho, indicate that the magmatism post collision has occurred in the active continental margin by extensional zones of the following the closure of the Paleotethys (Ahankoub, 2012). Granite and syenite rocks have been cut by mafic dikes. Mafic dikes are often formed in extensional tectonic settings related to mantle plume or continental break –up (Zhu et al., 2009). In this paper, we use the geochemistry and Nd-Sr isotope data to determined petrogenesis, tectono-magmatic setting and age of Misho mafic dikes. Materials and methods After petrography study of 30 thin sections of mafic dike rocks, 8 samples were selected for whole-rock chemical analyses using ICP-MS and ICP-AES instruments by ACME Company in Vancouver, Canada. We prepared 6 sample For Sm-Nd and Rb-Sr analysis. Sr and Nd isotope ratios were measured with a thermal ionization mass spectrometer, VG Sector 54–30 at the Nagoya University. The isotope abundances of Rb, Sr, Nd, and Sm were measured by the ID method with a Finnigan MAT Thermoquad THQ thermal ionization quadrupole mass spectrometer at the Nagoya University. NBS987 and JNdi-1 were measured as natural Sr and Nd isotope ratio standards (Tanaka et al., 2000). Averages and 2σ errors for the repeated analyses of the standards during this study were as follows: NBS987 87Sr/86Sr=0.710264± 0.00001 (1 σ, n=9) and JNdi-1 143Nd/144Nd= 0.512097± 0.00001 (1σ, n=9). Results Results of the ICP-AES and ICP-MS analysis present that dikes chemical compounds contain SiO2 = 50.94 – 48.3%, TiO2 = 1.53 -1.43%, Al2O3= 16.37 -15. 64 and MgO = 6.61 -5. 54. Major and trace elements display the natural of the with in plate Calc-Alkalin basalts of the metaluminous. Amounts of the Mg # indicate the variety of the fractional crystallization processes (ol and Cpx) in these rocks. Also, the low Nb / La refers to crustal assimilation during fractional crystallization processes. Chondrite-normalized REE patterns of the samples (Sun and McDonough, 1989), indicate an enrichment LREE / HREE because of low partial melting of garnet in the source (Martin, 1999). The low degree of partial melting of the mantle caused LREE enriched to HREE (Wass and Rogers, 1980). There are Eu Positive anomalies that are due to the accumulation of plagioclase. REE normalized patterns to Chondrite point out the enrichment REE and Tb samples by separation amphibole, pyroxene, Hornblende, titanite and rutile (Thirlwall et al., 1994). Spider diagram (Sun and McDonough, 1989) displays enrichment Rb, Th and U elements and depletion in Nb, Ti and p because of source depletion or Nb minerals existence (such as rutile, ilmenite and spinel). Enrichment Cs, Th, U, Nb and Ti, p negative anomalies of the mafic dike are similar to geochemical characteristics of continental margin rocks. Nb, Ti negative anomalies and Pb positive anomalies demonstrate the interference of the crust in magmatic source (Martin, 1999). The TDM model ages of mafic dikes are 1.2 -1.8 milliard years that show time of the separation of the source of mafic rocks of the Proterozoic crust. Also Sr-Rb data indicate the formation of Misho mountain mafic dikes at 232 ma years age. The εNd (T) is -1 to -4 that indicates the array mantel component of the mafic dike. Discussion Geochemistry data indicate that Misho mafic dikes are similar to calc-alkaline basalts of the oceanic island basalts (OIB) whereas Nb and Ti negative anomalies of the trace elements patterns are similar to crustal contamination. Negative amount of the εNd(T) indicated depleted mantel source (array mantel) with some continental crust contamination during AFC processes . Base on the results of analysis, the upper crust is the best candidates for magma contamination of the mafic dikes in Misho. Isotopic data indicated to replace mafic dike 232ma years ago by closing of paleotethys and forming the extension zone (break up) in active continental margin. Acknowledgement We thank Professor Yamamoto, head of geochemistry department of the Nagoya University for help .We are grateful to professor Karimpour, Chief Editor of the Journal of Economic Geology, and three anonymous reviewers for their constructive suggestions and comments. Reference Ahankoub, M., 2012. Petrogenesis and geochemistry east Misho granitoides (NW of Iran). Ph.D. Thesis, Tabriz University, Tabriz, Iran, 171 pp. (in Persian with English abstract) Eftekharnejad, J., 1981. Tectonic division of Iran with respect to sedimentary basins. Journal of Iran Petroleum Society, 82(3): 19–28. (in Persian with English abstract) Martin, H, 1999. Adakitic magmas: modern analogues of Archaean granitoids. Lithos, 46(3): 411–429. Metcalfe, I., 2006. Paleozoic and Mesozoic tectonic evolution and palaeogeography of East Asian crustal fragments: the Korean Peninsula in context. Gondwana Research, 9(1-2): 24–46. Moayyed, M. and Hossainzade, G., 2011. Petrology and petroghraphy of A- type Granitoides of the East-Misho Mountain with theory on its geodynamic importance. Journal of Mineralogy and Crystalography, 3(19): 529–544. (in Persian with English abstract) Sun, S.S. and McDonough, W.F., 1989. Chemical and isotopic systematic of ocean basalts: implications for mantle composition and process. In: A.D. Saunders and M.J. Norry (Editors.), Magmatism in the Ocean Basins. Geological Society, London, pp. 313–345. Tanaka, T., Togashi, S., Kamioka, H., Amakawa, H., Kagami, H., Hamamoto, T. and Yuhara, M., 2000. JNdi-1: a neodymium isotopic reference in consistency with LaJolla neodymium. Chemical Geology, 168(3-4): 279–281. Thirlwall, M.F., Smith, T.E., Graham, A.M., Theodorou, N., Hollings, P., Davidson, J.P. and Arculus, R.J., 1994. High field strength element anomalies in arc lavas; source or process? Journal of Petrology, 35(3): 819–838. Wass, S.Y. and Rogers, N.W., 1980. Mantle metasomatism- precursor to alkaline continental volcanism. Geochimica et Cosmochimica Acta, 44(11): 1811- 1823. Zhu, D.C., Chung, S.L., Mo, X.X., Zhao, Z.D., Niu, Y.L., Song, B. and Yang, Y.H., 2009. The 132 Ma Comei–Bunbury Large Igneous Province: remnants identified in presentday southeastern Tibet and southwestern Australia. Geology, 37(7): 583–586. Zhu, D.C., Mo, X.X., Zhao, Z.D., Niu, Y.L., Wang, L.Q., Chu, Q.H., Pan, G.T., Xu, J.F. and Zhou, C.Y., 2010. Presence of Permian extension- and arc-type magmatism in southern Tibet: paleogeographic implications. Geological Society of America Bulletin, 122(7-8): 979–993.

431-455

Authors: Ebrahim Tale Fazel; Behzad Mehrabi; Hassan Zamanian; Masoumeh Hayatalgheybi

Introduction The Senj deposit has significant potential for different types of mineralization, particularly porphyry-like Cu deposits, associated with subduction-related Eocene–Oligocene calc-alkaline porphyritic volcano-plutonic rocks. The study of fluid inclusions in hydrothermal ore deposits aims to identify and characterize the pressure, temperature, volume and fluid composition, (PTX) conditions of fluids under which they were trapped (Heinrich et al., 1999; Ulrich and Heinrich, 2001; Redmond et al., 2004). Different characteristics of the deposit such as porphyrtic nature, alteration assemblage and the quartz-sulfide veins of the stockwork were poorly known. In this approach on the basis of alterations, vein cutting relationship and field distribution of fluid inclusions, the physical and chemical evolution of the hydrothermal system forming the porphyry Cu-Mo (±Au-Ag) deposit in Senj is reconstructed. Materials and Methods Over 1000 m of drill core was logged at a scale of 1:1000 by Pichab Kavosh Co. and samples containing various vein and alteration types from different depths were collected for laboratory analyses. A total of 14 samples collected from the altered and least altered igneous rocks in the Senj deposit were analyzed for their major oxide concentrations by X-ray fluorescence in the SGS Mineral Services (Toronto, Canada). The detection limit for major oxide analysis is 0.01%. Trace and rare earth elements (REE) were analyzed using inductively coupled plasma-mass spectrometery (ICP-MS), in the commercial laboratory of SGS Mineral Services. The analytical error for most elements is less than 2%. The detection limit for trace elements and REEs analysis is 0.01 to 0.1 ppm. Fluid inclusion microthermometry was conducted using a Linkam THMS600 heating–freezing stage (-190 °C to +600 °C) mounted on a ZEISS Axioplan2 microscope in the fluid inclusion laboratory of the Iranian Mineral Processing Research Center (Karaj, Iran). Results The Cu-Mo Senj deposit covering an area about 5 km2 is located in the central part of the Alborz Magmatic Arc (AMA). The Nb/Y versus Zr/TiO2 diagram (after Winchester and Floyd, 1977) illustrates a typical trend for the magmas in the Senj magmatic area–starting from basaltic and evolving to dacite/rhyodacitic compositions, with few data plotting in the alkali basalt field. Most of the igneous rocks plot within the medium- and high-K fields in the K2O versus SiO2 diagram. The igneous rocks from the Senj area define a typical high-K calc-alkaline on SiO2 versus K2O diagram (Le Maitre et al., 1989). All studied rocks show similar incompatible trace element patterns with an enrichment of large ion lithophile elements (LILE: K, Rb, Ba, Th) and depletion of high field strength elements (HFSE: Nb and Ti), which are typical features of magmas from convergent margin tectonic settings (Pearce and Can, 1973). At least three veining stages namely QBC, QM, and QP which are related to alteration and mineralization are distinguished at the Senj mineralized area. Three distinct alteration assemblages including K-feldspar-biotite-sericite-quartz, quartz-sericite-K-feldspar-pyrite, and K-feldspar-biotite-sericite-quartz, are distinguishable with these veins. About 80 % of the copper at Senj is associated with the early QBC-stage veins, with another 5 to 15 % in the QM-and QP-stage veins. About 70 % of the molybdenite occur in QM veins. Discussion Fluid inclusion distribution, fluid chemistry, and homogenization behavior document that S2-type fluids are samples of magma-derived aqueous-saline fluids characterized by high salinity and temperature, and high Cu content. Such parental fluids scavenged Cu and Mo from the melt below and transported them to the hydrothermal system above. The increased abundance of S- and LV-types inclusion coinciding with the highest grade Cu mineralization (early QBC-stage veins) at the Senj deposit suggests that brine-vapor unmixing and phase separation plays an important role in Cu-ore precipitation and alteration zonation. In addition to unmixing, cooling and water-rock interaction also played important roles in chalcopyrite precipitation at the Senj deposit. Compositions, deposit-scale distribution, and trapping conditions of fluid inclusions can be explained by the continued influx of a parental high salinity magmatic hydrothermal fluid, with no significant change in the bulk composition of the input fluid over the integrated lifetime of ore metal precipitation and vein formation. Fluid inclusion evidence and vein-cutting relationships indicate that molybdenum mineralization (QM vein) occurred at moderate temperatures coinciding with phyllic alteration, rather than from later, lower temperature fluids. Furthermore, early fluids decompressed rapidly relative to cooling, forming quartz-stockwork veins with K-silicate alteration at depth and QP veins at shallower levels in the Senj deposit. Later, as the hydrothermal system waned, the rate of decompression relative to fluid cooling slowed, causing the fluid to remain above its solvus, forming barren quartz-dominated veins with quartz-kaolinite±illite alteration which overprint much of the deposit. References Heinrich, C.A., Günther, D., Audétat, A., Ulrich, T. and Frischknecht, R., 1999. Metal fractionation between magmatic brine and vapor, determined by micro-analysis of fluid inclusions. Geology, 27(7): 755–758. Le Maitre, R.W., Bateman, P., Dudek, A., Keller, J., Lameyre, J., Le Bas, M.J., Sabine, P.A., Schmid, R., Sorensen, H., Streckeisen, A., Woolley, A.R. and Zanettin, B., 1989. A classification of igneous rocks and glossary of terms. Blackwell Scientific Publications, Oxford, 193 pp. Pearce, J.A. and Can, J.R., 1973. Tectonic setting of basic volcanic rocks determined using trace elements analysis. Earth and planetary science letter, 19(2): 290-300. Redmond, P.B., Einaudi, M.T., Inan, E.E., Landtwing, M.R. and Heinrich, C.A., 2004. Copper deposition by fluid cooling in intrusion-centered systems: New insights from the Bingham porphyry ore deposit, Utah. Geology, 32(3): 217–220. Ulrich, T. and Heinrich, C.A., 2001. Geology and alteration geochemistry of the porphyry Cu– Au deposit at Bajo de la Alumbrera, Argentina. Economic Geology, 96(8): 1719–1742. Winchester, J.A. and Floyd, P.A., 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology, 20(5): 325-343.

473-491

Authors: Bahareh Fazeli; Mahmoud Khalili; Roy Beavers; Mahin Mansouri Esfahani; Zahra Loghmani Dastjerdi

Introduction The generation and evolution of granitic magmas has been a hot debated subject among petrologists. The diversity of their origin has led different authors to propose that these rocks are not simple in their origin and might be generated in more ways than one. In the past several decades, many petrologists used a variety characteristics to subdivide the granitoid rocks. Such proposals have of course been forward by Chappell and White (1974) for the granitoids of Eastern Australia. They divided these granitoids into two distinct types (I-and S-type granitic rocks), which they interpreted as being derived from igneous and sedimentary source rocks, respectively. The Ghaleh Yaghmesh plutonic massif is located in the most western part of Yazd and it forms a part of the Urumieh-Dokhtar magmatic belt. The belt is response to subduction of Neo-Tethyan oceanic crust beneath central Iran (Alavi, 1994). During Cretaceous-Late Tertiary, numerous granitoid bodies were exposed in this belt, many of which have been studied by a number of workers (e.g. Sepahi and Malvandi, 2008; Honarmand et al., 2013; Kananian et al., 2014). The massif composed of diorite, quartzdiorite, tonalite, granodiorite and granite (Oligocene) intruded into the Eocene volcanic and pyroclastic rocks including rhyolite, rhyodacite, andesitic, rhyodacitic and rhyolitic tuff. The main purpose of the present paper is to describe the petrography, and whole rock geochemistry of the Ghaleh Yaghmish granitoids as well as discussing their petrogenetic and tectonic significance in the light of the regional geological framework of the study area. Materials and methods After field studies and sampling, fifty thin sections were prepared for petrographic study. Twenty-one fresh samples were selected for XRF chemical analysis performed at the Southern Methodist University (Dallas - USA). Thin polished sections of granodiorite rocks were prepared for composition determining and structure formula calculation of amphibole minerals by Cameca SX50 microprobe device at the Oklahomacity University (Norman - USA). Results The studied plutonic rocks are dominated by plagioclase, orthoclase, quartz, amphibole (magnesio hornblende and actinolite hornblende), biotite, and pyroxene. Zircon, apatite, sphene, tourmaline and opaque minerals as the common accessory and chlorite, epidote and calcite are the secondary minerals. On the base of petrographic observation as well as mineral-chemistry and geochemical data, the granitoid massif is classified as I-type (magnetite series), calc – alkaline and metaluminous composition. The rocks under discussion are characterized by the high level of LILE (Ba, Sr, K and Cs) and the negative anomaly of HFS elements (Ti, Nb, Zr and Y) indicating the subduction related magmatism. The Ghaleh Yaghmesh granitoids are cogenetic and possibly developed in subduction zone related to active continental margin calc – alkaline volcanic arcs. Mixing process of acidic and basic magmas is likely involved in generation of the rocks being studied. Discussion The parent magma probably formed by partial melting of amphibolites with some sedimentary materials. Fractional crystallization of melt in the higher levels of crust gave rise to various rock types. Mantle – derived basaltic magmas emplaced into the lower crust most likely provide heat for partial melting )Clemens et al., 2011(. Field evidences such as the presence of mafic microgranular enclaves having sharp boundaries with the host rocks (Zorpi et al., 1989; Didier, 1991), petrographic observations (similar mineralogy of MME and the host rock (Didier, 1991; Didier and Barbarin, 1991), the occurrence of accicular apatite (Zorpi et al., 1989; Didier, 1991), the corroded margin of amphibole and plagioclase (Zorpi et al., 1989; Shelley, 1993) and the abundance of biotite and hornblende in MME compared to the host rock (Ellis and Thompson, 1986)) and geochemical criteria (range of silica from 51.35 to 70.78) indicate that magma mixing process was likely responsible for the formation of the rocks being studied. Acknowledgements The authors would like to thank the University of Isfahan for the financial support. We also thank the Southern Methodist University (SMU) (Dallas - USA) for the XRF chemical analysis undertaken for this project. References Alavi, M., 1994. Tectonics of Zagros orogenic belt of Iran, new data and interpretation. Tectonophysics, 229(3): 211–238. Chappell, B.W. and White, A.J., 1974. Two contrasting granite types. Pacific Geology, 8: 173-174. Clemens, J.D., Stevens G., and Farina, F., 2011. The enigmatic sources of I-type granites: The peritectic conexión. Lithos, 126(3): 174–181. Didier, J., 1991. The main types of enclaves in the Hercynian granitoids of the Massif Central, France. In: J. Didier and B. Barbarin (Editors), Enclaves and Granite Petrology. Developments in Petrology, V. 13. Elsevier, Amsterdam, pp. 47–61. Didier, J. and Barbarin, B., 1991. Enclaves and granite petrology.Developments in Petrology, V. 13. Elsevier, Amsterdam, 625 pp. Ellis, D.J. and Thompson, A.B., 1986. Subsolidus and partial melting reactions in the quartz-excess and water deficient conditions of peraluminous melts from mafic rocks. Journal of Petrology, 27(1): 91-121. Honarmand, M., Rashidnejad-Omran, N., Corfu , F., Emami, M. H. and Nabatian, G., 2013. Geochronology and magmatic history of a calc-alkaline plutonic complex in the Urumieh-Dokhtar Magmatic Belt, Central Iran: Zircon ages as evidence for two major plutonic episodes. Neues Jahrbuch fur Mineralogie, Abhandlungen, 190(1): 67–77. Kananian, A., Sarjoughian, F., Nadimi A., Ahmadian, J. and Ling, W., 2014. Geochemical characteristics of the Kuh-e Dom intrusion, Urumieh–Dokhtar Magmatic Arc (Iran): Implications for source regions and magmatic evolution. Journal of Asian Earth Sciences, 90: 137-148. Sepahi, A.A. and Malvandi, F., 2008. Petrology of the Bouein Zahra-Naein Plutonic Complexes, Urumieh-Dokhtar Belt, Iran: With Special Reference to Granitoids of the Saveh Plutonic Complex. Neues Jahrbuch für Mineralogie-Abhandlungen. Journal of Mineralogy and Geochemistry, 185(1): 99–115. Shelley, D., 1993. Igneous and metamorphic rocks under the microscope. Chapman and Hall, London, 630 pp. Zorpi, M.J., Coulon, C., Orisini, J.B. and Concirta, C., 1989. Magma mingling, zoning and emplacement in calk-alkaline granitoid plutons. Tectonophysics, 157(4): 315-326.

507-524

Authors: Maryam Feyzi; Mohammad Ebrahimi; Hossein Kouhestani; Mir Ali Asghar Mokhtari

Introduction The Aqkand Cu occurrence, 48 km north of Zanjan, is located in the Tarom subzone of the Western Alborz-Azerbaijan structural zone. Apart from small scale geological maps of the area, i.e., 1:250,000 geological maps of Bandar-e-Anzali (Davies, 1977) and 1:100,000 geological maps of Hashtjin (Faridi and Anvari, 2000) and a number of unpublished perlite exploration reports, prior to this research no work has been done on Cu mineralization at Aqkand. The present paper provides an overview of the geological framework, the mineralization characteristics, and the results of geochemistry study of the Aqkand Cu occurrence with an application to the ore genesis. Identification of these characteristics can be used as a model for exploration of this type of copper mineralization in the Tarom area and elsewhere. Materials and methods Detailed field work has been carried out at different scales in the Aqkand area. About 35 polished thin and thin sections from host rocks and mineralized and altered zones were studied by conventional petrographic and mineralogic methods at the University of Zanjan. In addition, a total of 6 samples from ore zones at the Aqkand occurrence were analyzed by ICP-MS for trace elements and REE compositions at Kimia Pazhuh Alborz Co., Isfahan, Iran. Results and Discussion The oldest units exposed in the Aqkand area are Eocene volcanic rocks which are overlain unconformably by Oligocene acidic rocks. The Eocene units consist of lithic and vitric tuff with intercalations of andesitic basalt lavas (equal to Karaj Formation, Hirayama et al., 1966). The andesitic basalt lavas show porphyritic texture consisting of plagioclase and altered ferromagnesian minerals set in a fine-grained groundmass. The Oligocene acidic rocks consist of rhyolite-rhyodacite, perlite, pitchstone and ignimbrite. These rocks are exposed as domes and lava flows. The rhyolite-rhyodacite lavas usually show onion-skin weathering and locally display flow bands. Rapid cooling of rhyolitic-rhyodacitic lavas has resulted in the formation of volcanic glasses (obsidian). Hydration of these volcanic glasses by hydrothermal fluids caused perlite formation which is located in the lower parts of the rhyolitic-rhyodacitic domes. Copper mineralization at Aqkand occurs as Cu-bearing quartz-fluorite veins in Eocene andesitic basalt lavas. The main ore vein reaches up to 50 m in length and average of 2 m in width. It has NW-trend and mostly dips NE. Six stages of mineralization can be distinguished at the Aqkand Cu occurrence. Stage-1 is characterized by

553-568

Authors: Mahshid Malekian Dastjerdi; Seyyed Saeid Mohammadi; Malihe Nakhaei; Mohammad Hossein Zarrinkoub

Introduction The study area is located 12km away from the north east of Sarbisheh at the eastern border of the Lut block (Karimpour et al., 2011; Richards et al., 2012). The magmatic activity in the Lut blockhas begun in the middle Jurassic (165-162 Ma) and reached its peak in the Tertiary age (Jung et al., 1983; Karimpour et al., 2011). Volcanic and subvolcanic rocks in the Tertiary age cover over half of the Lut block with up to 2000 m thickness and they were formed due to subduction prior to the collision of the Arabian and Asian plates (Jung et al., 1983; Karimpour et al., 2011). In the Kangan area, the basaltic lavas cropped out beyond the above intermediate to acid volcanic rocks. In this area, bentonite and perlite deposits have an economic importance. The main purpose of this paper is to present a better understanding of the tectono-magmatic settings of volcanic rocks in the northeast of Sarbisheh, east of Iran based on their geochemical characteristics. Materials and methods Fifteen samples were analyzed for major elements by inductively coupled plasma (ICP) technologies and trace elements by using inductively coupled plasma mass spectrometry (ICP-MS), following a lithium metaborate/tetraborate fusion and nitric acid total digestion, at the Acme laboratories, Vancouver, Canada. Results The Kangan area is located at the northeast of Sarbishe, Southern Khorasan and the eastern border of the Lut block. In this area, basaltic lavas have cropped out above intermediate to acid lavas such as andesite, dacite, rhyolite (sometimes perlitic) .The main minerals in the basalt are plagioclase, olivine and pyroxene, in andesite contain plagioclase, pyroxene, biotite and amphibole and in acid rocks include plagioclase, quartz, sanidine, biotite and amphibole. Intermediate to acid rocks have medium to high-K calc-alkaline nature and basalt is alkaline. Enrichment in LREE relative to HREE (Ce/Yb= 21.14-28.7), high ratio of Zr/Y(4.79- 10.81), enrichment in LILE and negative anomaly of Eu, Nb, P, Ti, Ba and Sr in intermediate to acid lavas are characteristics of subduction related calc-alkaline magmatism. Geochemical characteristics such as high ratio of La/Yb (8.18), low content of Rb with tectonic setting discriminant diagrams show within plate environment for basalt. The constituent magma of the studied rocks originated from an enriched garnet lherzolite source in 100 to 110km depth. Discussion Enrichment in LREE relative to HREE (Ce/Yb= 21.14-28.7), high ratio of Zr/Y (4.79- 10.81), enrichment in LILE and negative anomaly of Eu, Nb, P, Ti, Ba and Sr in intermediate to acid lavas are characteristics of subduction related calc-alkaline magmatism. Tectonic setting discrimination diagrams show that andesite to dacitic rocks are located in active continental margin (Schandle and Gorton, 2002) and basalt is placed within the volcanic plate zone and continental rift type (Verma et al., 2006). Intermediate to acid rocks of Kangan area originated from lithospheric mantle (Moharami et al., 2014) that is enriched by sediment melt related metasomatism (Ersoy et al., 2010) whereas Kangan basaltic lava origin is Nb enriched (Wang et al., 2008; Sajona et al., 1996) mixed lithospheric - asthenospheric mantle (Moharamiet al., 2014). According to the trace elements diagrams (Ellam, 1992), partial melting depth for generation of Kangan area lavas was determined to be about 100 to 110Km. Because of absent crustal contamination instances in the basalt, it can be argued that ascending of magma has been rapid and probably similar to other alkali basalts in east of Iran, it may be related to deep fault systems. Acknowledgements The authors would like to thank the reviewers for their constructive comments which greatly contributed to the improvement of the manuscript. References Ellam, R.M., 1992. Lithospheric thickness as a control on basalt geochemistry. Geology, 20(2): 153-156. Ersoy, E.Y., Helvaci, C. and Palmer, M.R., 2010. Mantle source characteristics and melting models for the early-middle Miocene mafic volcanism in western Anatolia: implications for enrichment processes of mantle lithosphere and origin of K-rich volcanism in post-collisional settings. Journal of Volcanology and Geothermal Research, 198(1-2): 112-128. Jung, D., Keller, J., Khorasani, R., Marcks, C., Baumann, A. and Horn, P., 1983. Petrology of the Tertiary magmatic activity the northern Lut area, East of Iran. Geological Survey of Iran, Tehran, Report 51, 519 pp. Karimpour, M.H., Stern, C.R., Farmer, L., Saadat, S. and Malekezadeh, A., 2011. Review of age, Rb-Sr geochemistry and petrogenesis of Jurassic to Quaternary igneous rocks in Lut block, eastern Iran. Geopersia, 1(1):19-36. Moharami, F., Azadi, I., Mirmohamadi, M., Mehdipour Ghazi, J. and Rahgoshay, M., 2014. Petrological and Geodynamical Constraints of Chaldoran Basaltic Rocks, NW Iran: Evidence from Geochemical Characteris. Iranian Journal of Earth Sciences, 6(1): 31-43. Richards, J.P., Spell, T., Rameh, E., Razique, A. and Fletcher, T., 2012. High Sr/Y magmas reflect arc maturity, high magmatic water content, and porphyry Cu ± Mo ± Au potential: examples from the Tethyan arcs of central and eastern Iran and western Pakistan. Economic Geology, 107(2): 295–332. Sajona, F.G., Maury, R.C., Bellon, H., Cotton, J. and Defant, M., 1996. High field strength element enrichment of Pliocene-Pelistocene island arc basalts, Zomboanga Peninsula, Western Mindanao Philippines. Journal of Petrology, 37(3): 693–726. Schandl, E.S. and Gorton, M.P., 2002. Application of high field strength elements to discriminate tectonic setting in VMS environment. Economic Geology, 97(3): 629-642. Verma, S.P., Guevara, M. and Agrawal, S., 2006. Discriminating four tectonic settings: Five new geochemical diagrams for basic and ultrabasic volcanic rocks based on log- ratio transformation of major-element data. Journal of Earth System Science, 115(5): 485-528. Wang, Q., Wyman, D.A., Xu, J., Wan, Y., Li, C., Zi, F., Jiang, Z., Qiu, H., Chu, Z., Zhao, Z. and Dong, Y., 2008. Triassic Nb-enriched basalts, magnesian andesites, and adakites of the Qiangtang terrane (Central Tibet): evidence for metasomatism by slab-derived melts in the mantle wedge. Contributions to Mineralogy and Petrology, 155(4): 437-490.

593-607

Authors: Saeed Saadat

Introduction Ground magnetometer surveys is one of the oldest geophysical exploration methods used in identifying iron reserves. The correct interpretation of ground magnetic surveys, along with geological and geochemical data will not only reduce costs but also to indicate the location, depth and dimensions of the hidden reserves of iron (Robinson and Coruh, 2005; Calagari, 1992). Kalateh Naser prospecting area is located at 33° 19َ to 33° 19ََ 42" latitude and 60° 0' to 60° 9َ 35" longitude in the western side of the central Ahangaran mountain range, eastern Iran (Fig.1). Based on primary field evidences, limited outcrops of magnetite mineralization were observed and upon conducting ground magnetic survey, evidence for large Iron ore deposits were detected (Saadat, 2014). This paper presents the geological and geochemical studies and the results of magnetic measurements in the area of interest and its applicability in exploration of other potential Iron deposits in the neighboring areas. Materials and methods To better understand the geological units of the area, samples were taken and thin sections were studied. Geochemical studies were conducted through XRF and ICP-Ms and wet chemistry analysis. The ground magnetic survey was designed to take measurements from grids of 20 meter apart lines and 10 meter apart points along the north-south trend. 2000 points were measured during a 6-day field work by expert geophysicists. Records were made by Canadian manufactured product Magnetometer Proton GSM19T (Fig. 2). Properties of Proton Magnetometer using in magnetic survey in Kalateh Naser prospecting area is shown in Table 1. Total magnetic intensity map, reduced to pole magnetic map, analytic single map, first vertical derivative map and upward continuation map have been prepared for this area. Results The most significant rock units in the area are cretaceous carbonate rocks (Fig. 3). The unit turns to shale and thin bedded limestone in the central part and into red and white crystalline limestone towards the west, which sometimes can be referred as marble and skarn (Figs. 4, 5 and 6; Saadat, 2014). Iron mineralization is mostly observed in these units. Acidic to intermediate intrusive bodies consisting hornblende quartz monzonite, biotite granodiorite, pyroxene quartz diorite have outcrops in the north and northwestern part of the area (Fig. 3). Outcrops from andesite to dacite volcanic rocks in combination with ultra-mafic rocks can be seen in the southern part of the region. The geochemical results indicated F2O3 value range of %31 to %96. P2O5 of maximum %0.45 was observed and TiO2 varied from %0.02 to %0.54 (Tables 2 and 3 and Figs 7, 8 and 9). The highest values of iron and copper are found in the northern part, titanium and phosphorus are located in the southern part and manganese and vanadium are placed in the central sector. According to the obtained results, the highest magnetic susceptibility was associated with the skarn units and was measured at 34000*10-5 SI which is related to the mineralization of Iron in the area. Magnetic susceptibility of limestone crystalline units were close to 50*10-5 SI and marble was less than 10* 10-5 SI which highlights the influence of iron mineralization in the carbonates rocks. This value was around 80*10-5 SI for intrusive rocks such as hornblende quartz monzonite in the area (Table 4). Ground magnetic studies suggest minimum of 40000 nT and maximum of 70000 nT total magnetic intensity in the area (Fig. 10-A; Ryahei, 2013). Utilizing the Reduced to Pole Magnetic Filter is to locate the anomalies in the study area (Fig. 11-A). Since magnetic declination causes a degree of deviation between the source and magnetic anomalies, the said filter is applied to magnetic data and ultimately, analysis is done based on the magnetic data transferred to the pole (Nakatsuka and Okuma, 2006; Clark, 1997). The results of reduce to pole magnetic map for this area yielded three large and two small magnetic anomalies (Figs 12-A and 12-B). The upward continuation maps were taken with 5m, 10m, 20m, 30m, 40m, and 50m. Smaller anomalies tend to disappear more comparing the 5m to 20m continuation maps respectively, and a homogenous large anomaly starts to form in the 50m map (Fig. 13). Large and clear anomalies continue to be present in the 50m continuation map and only two smaller anomalies are disappeared from the west of the area (Ryahei, 2013). Discussion The results of geological, geochemical and magnetic susceptibility measurements indicate that magnetic anomalies in the Kalate-Naser area is related to the iron mineralization in this area. Lower amount of magnetic susceptibility in intrusive mass outcrops also indicate that these intrusive rocks did not play the main role in iron mineralization and were in fact have been weakly altered. It can only be concluded that the intrusive mass that led to mineralization sits beneath, at a higher depth. The initial geophysical survey results are closely comparable to the powder drilling trials that confirm magnetite mineralization to the named depth (Saadat, 2014). Thus far, 1.5 Million ton of Iron ore deposits have been confirmed in the area and exploration continues during production. The obtained results once again highlight the importance of ground magnetic surveys that combined with other exploration methods can reduce costs, increase efficiency and simplify the exploration process. Methodology and results of the magnetic measurements conducted in Kalateh Naser can help to better understand the magnetite bodies in the neighboring areas. Acknowledgement Hereby, I would like to thank my colleagues particularly, Ryahi, Shokri, Madani, Ebrahimzadeh, Salari, Maldar family, Ghoorchi, amongst others that assisted with field visits, mapping, processing and data analysis. References Calagari, A.A., 1992. Principals of geophysics exploration. Tabesh press, Tabriz, 588 pp. Clark. D.A., 1997, Magnetic petrophysics and magnetic petrology: aids to geological interpretation of magnetic surveys. Journal of Australian Geology and Geophysics, 17(2): 83-103. Nakatsuka, T. and Okuma S., 2006. Reduction of magnetic anomaly observations from helicopter surveys at varying elevations. Exploration Geophysics, 37(1): 121-128. Robinson, E.S. and Coruh, C. (translated by Haydarian Shahri, M.R.), 2005. Basic exploration geophysics. Ferdowsi University of Mashhad Press, Mashhad, 750 pp. Ryahei, H., 2013. Magnetite data of Kalateh Naser prospecting area. Madan Yaran Lut Company, Mashhad, Internal report, Report 1, 17 pp. Saadat, S., 2014. Final exploration report of Kalateh Naser prospecting area. Madan Yaran Lut Company, Mashhad, Internal report, Report 3, 100 pp.