Journal of Economic Geology

285-305

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.

1-20

Authors: Mahdi Bemani; Seyed Hossein Mojtahedzadeh; Amir Hossein Kouhsari

Introduction
Mohammad-abad Oryan is the only potential source of borate in the North-east of Iran located in 50 km South of Sabzevar. The area is located in tuff marl, tuffaceous marl, volcanic braccia and tuff braccia structures. Remote sensing techniques, geological studies and integration of this data in GIS were applied in an area of about 600 square kilometers to locate the promising areas of borate mineralization for detailed studies (Bemani, 2012). The aim of this detailed geochemical study is to confine the anomaly areas for exploratory drilling and trenching.

Materials and methods
Field studies were carried out in 9 geological traverses, mainly in Tonakar and Borje Kharkan area and 126 brine samples were taken from hydrothermal springs and 13 rock samples were taken from trenches. All the samples were analyzed for four elements, including B, K, Li and Mg. In order to determine the threshold quantities of the samples and isolation of anomaly, the data were analyzed using statistical methods including classical statistics, fractal geometry and EDA methods (Bemani, 2012).

Result
Initial data analysis showed that there were no censored data. Also, by applying statistical hypothesis testing, no significant relation was observed between the elements in the two areas (except for Li). Therefore, all the statistical analyses were carried out separately.
After outlier correction, based on the amount of skewedness and histograms and probability plots of different elements, it became clear that none of the elements in the raw data distribution were normal and required to be transformed to be close to normal. In this study, logarithmic and three-parameter logarithm transformation were used in order to normalize the data . Based on the mean values, standard deviation of the normalized data, and background value and threshold, probable and possible anomalies were obtained and geochemical anomaly maps were drawn to identify the promising areas.
With the exception of the fractal pattern, anomaly separation methods are based on the differences of fractal dimensions between communities of geochemical data (Hasanipak and Sharafoddin, 2005). In this study, concentration area fractal method was used to separate anomalies from the background. Using fractal geometry, threshold value corresponding to the two areas (Tonakar and Borje Kharkan) were obtained and were plotted separately on geochemical maps.
Exploratory data analysis (EDA) is an approach to analyze data sets to summarize their main characteristics, often with visual methods (Filliben and Heckert, 2005). Exploratory data analysis is a useful method for analysis of geochemical exploration data. This is a statistical method known as the Robust Statistic classification (Carranza, 2009). In geochemical exploration, box plots, histograms and scatter plot are more practical. According to the box plots, the data of Tonakar and Borje Kharkan areas were classified and threshold levels were determined (Bemani, 2012).

Discussion
Using the results obtained from different methods, geochemical maps of each area were prepared for all the elements and thresholds were obtained for each method. Moreover, the geochemical maps of each area were plotted for each element. According to the geochemical maps of Tonakar area, boron anomaly was observed in the East and West zones and the anomaly of the latter is larger. These areas were recommended for further detailed exploration and borehole drilling. Also, geochemical maps of Borje Kharkan showed anomaly in the central zone for all of the elements. The results showed that the highest and the lowest amounts of boron in brines samples vary between 6 ppm to 5930 ppm. Among boron and the three other elements (i.e. lithium, magnesium and potassium) a significant correlation was not observed. In terms of frequency, in most cases brines with high levels of boron (more than 1000 ppm) were concentrated in the South East of the Tonakar area. So, this area was suggested for detailed exploration (Bemani et al., 2014). Generally speaking, for considering the spatial distribution of data the fractal method could better identify the anomalies. Also, EDA is a quick and easy method to detect anomalies.

Acknowledgment
The authors are grateful to the Kaniran Mining Company and the south Khorasan branch of the Iranian Mining Engineering Organization for their financial support of this study.

References
Bemani, M., 2012. Prospecting and Exploring of Borax in the south of Sabzevar, combination of remote sensing, field surveying and geochemical studying. M.Sc. Thesis, University of Yazd, Yazd, Iran, 137 pp (in Persian with English abstract).
Bemani, M., Mojtahedzadeh, S.H. and Kohsari, A.H., 2014. Investigation of geology, mineralogy and genesis of Mohammadabad-Oryan index boron (south of Sabzevar). Iranian Journal of Crystallography and Mineralogy 22(1): 173- 186 (in Persian with English abstract).
Carranza, E.J.M., 2009. Geochemical Anomaly and Mineral Prospectivity Mapping in GIS. In: M. Hale (Editor), Handbook of exploration and environmental geochemistry. Elsevier, Amsterdam, pp. 51-115.
Filliben, J.J. and Heckert, A., 2005. Exploratory data analysis. Engineering Statistics Handbook, Internet, National Institute of Standards and Technology, http://www.itl.nist.gov/div898/handbook/eda/section3/eda356.htm.
Hasanipak, A.A. and Sharafaddin, M., 2005. Exploratory Data Analysis.Tehran University press, Tehran 996 pp (in Persian).

39-59

Authors: Mansoore Maghsoudloo Mahalli; Behnam Shafiei Bafti

Introduction
Oolitic iron formations are sedimentary rocks with >5 vol.% oolites and >15 wt.% iron, corresponding to 21.4 wt.% Fe2O3 (Young, 1989; Petranek and Van Houten, 1997; Mucke and Farshad, 2005). In Iran, new iron oolite-bearing members have been identified in the Lashkarak Formation (lower-middle Ordovician) in the Abarsej, Dehmola and Simehkuh sections, eastern Alborz (Ghobadi Pour et al., 2011). At present, the mineralogy and geochemistry of these members are not known. Consequently, research reported here was conducted to reveal the mineralogical and geochemical characteristics of Ordovician oolitic iron formationmembers and to discuss their genesis and economic importance.

Materials and Analyses
Field geology and sampling was carried out to collect 25 samples from the ooliticiron formation members in the Abarsej, Dehmola and Simehkuh section in eastern Alborz. Samples were prepared for polished-thin sections (n=10), XRD analysis (n=15). Whole-rock chemical analysis (n=15) by XRF for major elements and by ICP-ES for trace elements was performed by laboratories at the SarCheshmeh copper mine complex, Kerman, Iran. One sample was analyzed by SEM at the Wales Museum, UK.

Results
Microscopic studies show that the oolitic iron formation members are hosted by carbonate argillite rocks. They are mainly composed of oolites rather than pisoliths (small bodies somewhat larger and more irregular than oolites), whereas oolites have mainly ellipsoidal forms and locally spherical shapes. Most (6) oolites show banding with a central core. Simple oolites without a core are scarce. Mineralogically, oolites are mainly chamositic and hematitic in composition; goethite, pyrite and glauconite occur in traces and siderite is absent. Quartz, calcite and zircon are accessory minerals which are present in the groundmass. Geochemically, TFeO % of the oolitic iron formation horizons ranges from 8 to 48 % with an average of 21%. The CaO content ranges from 2 to 37% and SiO2 from 11 to 37 %. Based on TFeO % content, oolitic iron formation horizons are divided into two geochemical groups: 1: Low-grade iron formations ( the Abarsej section) (8) with TFeO< 23%, high MgO (0.82-0.96 %) and high CaO (32.99-37.22 %) and low TiO2 (0.45-0.62 %), and 2: High-grade iron formations (the DehMola and Simehkuh sections) with 23%
Discussion
Mineralogical characteristics combined with geochemical data show that anomalous values of Fe in studied carbonate argillite formations with respect to common sedimentary rocks are related to the abundance of iron-bearing oolites as oxides such as hematite and goethite, and the clay mineral chamosite. Based on Fe, Mg and Ca concentrations, oolitic iron formations can be divided into low-grade and high-grade iron formations. The former is characterized by chamosite and calcite, whereas the latter consists ofhematite and calcite. This research, along with available paleo-geographic and sedimentological information suggests that the iron for the formation of iron oolites was available from normal sea water and Fe could be carried as clastic particles along with clays or coating of clay particles derived from weathering and erosion of shales from adjacent land. High contents of K and Si in oolitic iron horizons, the presence of detrital zircon, quartz and clay minerals within oolites and also in the matrix of these rocks confirm the proposed model and show the important role of Fe-bearing clay minerals in the genesis of the primary chamositic oolites in an environment with pH=5-9 and medium-weak redox conditions (Maynard, 1983; Maynard, 1986). The abundance of hematite relative to goethite in the Fe-oolites, dense and elliptical oolites as well as the frequent occurrence of calcite veinlets cutting oolite beds has been attributed to diagenetic processes and the modification of chamosite and goethite to hematite. Our findings indicate that the studied members can be classified as low-grade oolitic iron formation (average 21 wt.% Fe) which do not have economic importance at present.

Acknowledgements
This study is part of the senior author's M.Sc thesis at Golestan University, Gorgan, Iran. Logistical and financial support was provided by the Research Grant to senior author. We are grateful to SarCheshmeh Copper Complex for XRF analyses and IMPERC for XRD measurements. We gratefully acknowledge Dr. Ghobadipour for SEM analysis in National Museum of Wales, Great Britain.

References
Ghobadi Pour, M., Popov, L.E., Kebriaee-Zadeh, M.R. and Baars C.H., 2011. Middle Ordovician (Darriwilian) Brachiopods associated with the Neseuretus bio-facies, Eastern Alborz Mountains, Iran. Memoirs of the Association of Australasian Palaeontologists, 42(3): 263-283.
Maynard, J.B., 1983. Geochemistry of sedimentary ore deposits. Springer-Verlag, NewYork, 382 pp.
Maynard, J.B., 1986. Geochemistry of oolitic iron ores, an electron microprobe study. Economic Geology, 81(8): 1473-1483.
Mucke, A.T. and Farshad, F., 2005. Whole-rock and mineralogical composition of Phanerozoic ooidal ironstones: Comparison and differentiation of types and subtypes. Ore Geology Reviews, 26(2): 227-262.
Petranek, J. and Van Houton, F.B., 1997. Phanerozoic ooidal ironstone. Czech Geological Survey, Special Papers 7: 70 pp.
Young, T.P., 1989. Eustatically controlled ooidal ironstone deposition: facies relationships of the Ordovician open-shelf ironstones of Western Europe. In: T.P. Young and W.E.G. Taylor (Editors), Phanerozoic Ironstones. Geological Society of London, Special Publication, 46(1): 51–64.

79-92

Authors: Hojjat Ollah Safari; Behnam Shafiei Bafti; Hassan Mohamadrezaei

Introduction
The Sar Cheshmeh copper deposit and indications of other deposits are located in the Dehaj-Sarduieh belt in the Kerman region (Khadem and Nedimovic, 1973). This belt is one of the most important provinces of Cu mineralization in Iran, with approximately 300 Cu deposits and prospects, includingtwenty of the porphyry copper type (Ghorbani, 2013). This belt, 300 km in length and 30–45 km width, is situated in the southern part of the Uramia-Dokhtar volcanic belt in central Iran (Shafiei, 2010). Zarasvandi (2004) has proposed that faulting has played a role in the location of copper deposition in this area.

Methods of Investigation
In order to check Zarasvandi’s hypothesis, the spatial relationship between faults and Cu deposits was investigated using remote sensing and GIS techniques together with field investigations in the Sar Cheshmeh area. The the following steps were used in this research:
1. Review of available data
2. Surface geology field studies
3. Preparation of digital overlay of Copper occurrences
4. Analysis of the relationshipof faulting to Copper occurrences
Using remote sensing techniques, a geometrically corrected satellite image was filtered with high pass and Sharpen Edge filters to detect possible lineaments (Lillesand and Keifer, 2008; Sabins, 1996). Directional filters (45º, 90º, 135º and 180º) were then applied to the processed image to enhance the linear structures. Subsequently,the major lineaments were documented in the field as major and minor faults (Safari et al., 2011). Four main faults, designated as the Rafsanjan, Mani, Gaud-e-Ahmar and Sar Cheshmeh faultswere determined to be major. These faults were digitized and overlaid on other data layers in GIS environment. The strikes, dips, striae and directions of movementof the faultswere measured at 20 locations in the field. Structural analyses were done with Rose diagrams, calculation of P-axes and preparation of a structural map.
Copper occurrences on the mineral distribution map of Lotfi, et al. (1993) were used in this study and the locations of somecopper occurrences were determined in the field using GPS. The locations and main characteristics of the copper occurrences were entered into a GIS map. Finally, aniso-fracture map, was prepared using the GIS environment based onfault lengths within a 1000 ×1000 mgrid and on the buffer map of ore occurrences relative to faults. The copper occurrence locations were overlaid on these prepared maps and the relationship between faults and ore occurrences locations was analyzed.
v Results
This research indicates that:
1.The faults in the Sar Cheshmeh area trend predominantly 090°-110°, 130°-150°, 050°-070° and 170°-190°.
2.The data show that three major NW- trendingfaults, the Mani, Gaud-e-Ahmar and Rafsanjan faults show right-lateral strike-slip movement and the two major E-W trending Sar Cheshmeh and Darreh Zar faults have left-lateral strike-slip displacements.
3. The control of the calculated P-axes shows that at least two older movements have happened along these faults.

Discussion
The results show that the main faults did not directly control the locations of the mineralized porphyries and veins, but that rather the locations are due tothe second-order faults. Also, the saturated occurrence locations have the closer relationship with main faults and most indexes are located near the Rafsanjan fault and its second-order faults.

References
Ghorbani, M., 2013. The Economic Geology of Iran: Mineral Deposits and Natural Resources. Springer Science, Business Media Dordrecht, Heidelberg, 581 pp.
Khadem, N. and Nedimovic, R., 1973. Exploration for ore deposits in Kerman Region. Geological Survey of Iran, Report Yu/53, 247 pp (in Persian).
Lillesand, T.M. and Kiefer, R.W., 2008. Remote sensing and image interpretation. John Wiley and Sons, New York, 756 pp.
Lotfi, M., Sadeghi, M.M. and Omrani, S.J., 1993. Mineral distribution map of Iran, scale: 1/1000000. Geologic Survey of Iran.
Sabins, F.F., 1996. Remote sensing principle and interpretation. Macmillan Education Australia, New York, 494 pp.
Safari, H., Pirasteh, S. and Shattri, B.M., 2011. Role of Kazerun Fault for Localizing Oil Seepage in the Zagros Mountains, Iran: an Application of GiT. International Journal of Remote sensing, 32(1): 1-16.
Shafiei, B., 2010. Lead isotope signatures of the igneous rocks and porphyry copper deposits from the Kerman Cenozoic magmatic arc (SE Iran), and their magmatic-metallogenetic implication. Ore Geology Reviews, 38: 27-36.
Zarasvandi, A.R., 2004. Geology and genesis of the Darreh-Zerreshk and Ali-Abad copper deposits, Southwest of Yazd, based on fluid inclusion and isotope studies. Ph.D. Thesis, Shiraz University, Shiraz, Iran, 280 pp.

117-128

Authors: Tahereh Rabani; Nader Taghipour; Reza Aharipour

Introduction
Maceral is a term to introduce organic components visible under a microscope (Stopes, 1935). The physical and chemical characteristics of macerals such as elemental composition, moisture content, hardness, density and petrographic characteristics differ. The differences in the physical and chemical characteristics of macerals are reflected in their industrial behavior.(Parkash, 1985). Petrographic analysis provides information on the various physical components of coals (Suwarna and Hemanto, 2007) and determination of quality of coal, coalification rate, composition and characteristics of coke and paleoenvironmental deposition (Taylor et al., 1998).

Sampling and methodology
Coal samples were collected from freshly mined coal from 11 coal seams of 4 active coal mines (Cheshlagh, Zemestan Yourt, Narges Chal and Cheshmehsaran) for organic petrography in the Gheshlagh coal deposits. All samples were collected and stored in plastic bags to prevent contamination and weathering.
Samples were prepared for microscopic analysis by reflected light following ASTM Standard procedure D2797-04. For microscopic study, coal samples were crushed to1-mm size fraction (18 mesh size), mounted in epoxy resin and polished. Three polished samples were prepared for each coal seam. The petrographic composition was obtained by maceral analyses under standard conditions (ISO 7404/3, 2009, for maceral analysis). Maceral point counting (based on 400 points) analyses were performed using an Olympus BX51 reflected light microscope. The terminology used to identify and describe the organic matter particles is the one proposed by the International Committee for Coal and Organic Petrology (ICCP, 1998; ICCP, 2001; Scott and Glasspool, 2007; Taylor et al., 1998; Stach et al., 1982; Hower et al., 2009; Hower and Wagner, 2012).

Organic petrography of theGheshlagh coal seams
The vitrinite maceral group is dominant in all coal seams (66.2 to 87.2 vol.%) and includes collodetrinite, collotelinite, and corpogelinite macerals. Collodetrinite maceral (20 to 65.6 vol.%) is the most abundant maceral in the vitrinite group and is associated with inertodetrinite and microspornite macerals. Callotelinite (8.4 to 46.7 wt%) occurs as a structureless, homogeneous mass in the Gheshlagh coal seams. The inertinite group (4.9 to 23.3 vol%) includes fusinite, semifusinite, macrinite, secretinite, funginite and inertodetrinite macerals. Fusinite (1.7 to12.7 vol.%) is present in all coal seams in the Gheshlagh area. Cell cavities of fusinite are filled mostly by corpogelinite and clay minerals. Semifusinite occurs in appreciable concentrations (2.1to 14.3vol.%) and Cell lumens of this maceral are filled with mineral matter, pyrite and clay.
The liptinite group (nil to 3.5 vol%) includes sporinite, cutinite and resinite macerals. Sporinite is the dominant maceral in the liptinite group (nil to 2.3 vol.%) and occurs as elongated thread-like or spindle-shaped bodies and occurs as microspores and megaspores. Resinite (nil to 0.1 vol.%) occurs as round to oval bodies and as fillings of the cell cavities of fusinite, semifusinite and funginite.
The mineral matter content of most of the Gheshlagh coal seams varies between 3.1 and 24.9 vol.%. Mineral matter occurs in primary ground mass or secondary cavity filling form and includes clay minerals, carbonate and sulphide.

Conclusion
Based on organic petrographic studies carried out on four active coal mines in the Gheshlagh area, the presence of three maceral groups were determined. The vitrinite group (66.2 to 87.2 vol%) is the dominant maceral group, and callodetrinite maceral (20 to 65.6 vol%) is also abundant. The inertinite group contenthas a range of 4.9 to 23.3 vol% while the fusinite and semifusinite macerals are the most abundant of this group. The lowest volume percentage of macerals belongs to the liptinite group (0 to 3.5 vol%) with 2.3 vol% espornitebeing the most abundant Maceral of this group. The presence of espornite maceral at megaspore size in the S2 and K5 coal seams is very noticeable. The content of mineral matter of these coal seams varied from 5 to 24.9 vol%.

Acknowledgements
The authors would like to thank the Eastern Alborz company employees for providing access to mines of the Gheshlagh area and sampling. We appreciate reviews for their constructive suggestions.
References Hower, J.C., O'Keefe, J.M.K., Watt, M.A., Pratt, T.J., Eble, C.F., Stucker, J.D., Richardson, A.R. and Kostova, I.J., 2009. Notes on the origin of inertinite macerals in coals: Observations on the importance of fungi in the origin of macrinite. International Journal of Coal Geology, 80(2): 135–143.
Hower, J.C. and Wagner, N.J., 2012. Notes on the methods of the combined maceral/ microlithotype determination in coal. International Journal of Coal Geology, 95(47-53): 47–53.
International Committee for Coal and Organic Petrology (ICCP), 1998. The new vitrinite classification (ICCP System 1994). Fuel, 77(5): 349–358.
International Committee for Coal and Organic Petrology (ICCP), 2001. The new inertinite classification (ICCP System 1994). Fuel, 80(4): 459–471.
ISO 7404–3, 2009. Methods for the petrographic analysis of bituminous coal and anthracite- Part 3: method of determining maceral group composition. Geneva, 7 pp, http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=42831
Parkash, S., 1985. Petrographic studies of coals from Alberta plains, coal research department, Alberta research. Edmonton, Alberta, Canada, 47 pp.
Scott, A.C. and Glasspool, I.J., 2007. Observations and experiments on the origin and formation of inertinite group macerals. International Journal of Coal Geology, 70(1-3): 55–66.
Stach, E., Mackowsky, M.T., Teichmuller, M., Taylor, G.H., Chandra, D. and Teichmuller, R. 1982. Stach's Textbook of Coal Petrology. Gebruder Borntraeger, Berlin-Stuttgart, 535 pp.
Stopes, M.C., 1935. On the petrology of banded bituminous coals. Fuel, 14: 4–13.
Suwarna, N. and Hermanto, B., 2007. Berau coal in East Kalimantan; Its petrographics characteristics and depositional environment. Journal Geologi Indonesia, 2(4): 191-206.
Taylor, G.H., Teichmüller, M., Davis, A., Diessel, C.F.K., Littke, R. and Robert, P., 1998. Organic Petrology. Gebrüder Borntraeger, Berlin. 704 pp.

147-165

Authors: Karim Abdollahi Silabi; Seyed Mohsen Tabatabaei Manesh; Somaye Karimi

Introduction
The area studied is located north of Azna (Lorestan Province) in a small portion of the Sanandaj – Sirjan structural zone (Mohajjel et al., 2003).This area is part of the Zagros orogenic belt, formed by the opening and closure of Neotethyan ocean. From NE to SW, it consists of three parallel tectonic regions: the Orumieh-Dokhtar magmatic belt, the Sanandaj-Sirjan structural zone and the Zagros thrust-fold belt (Ghasemi and Talbot, 2005).
The Sanandaj-Sirjan structural zone is a metamorphic belt composed mostly of greenschist, amphibolite and eclogite facies rocks. The development of the zonetook placeduring the opening of the Tethys ocean and its subsequent closing during the Cretaceous and earlyTertiary convergence of the Afro-Arabian and Eurasian plates (Mohajjel and Fergusson, 2000). The second stage of metamorphism and deformation of the zone, designated D2, is the most important, resulting from the opening and closure of the Neotethyan ocean and the collision of the Arabian plate with the southwestern part of central Iran in the Late Cretaceous to Tertiary (Laramideorogenic phase) (Ghasemi and Talbot, 2005; Aghanabati, 2004; Mohajjel et al., 2003; Mohajjel and Fergusson, 2000; Alavi, 1994). In the Sanandaj-Sirjanzone, which includes the Azna area, Cretaceous granitic intrusions into the schists were followed byfolding and faulting. The intrusions produced contact metamorphism, and have lens-shaped outlines, trendingNW-SE. Consequently, the Azna area has a varied petrologic assemblage with polyphase metamorphism and deformation, including schists, metabasites and mylonitic granites. The phases include: 1. Deformation D1, and dynamothermal metamorphism (M1),a result of the subduction of Neotethysoceanic crust beneath the Iranian plate in the Late Jurassic. 2.Deformation D2, and thermal metamorphism (M2),a result of Paleocene continental collision and 3. Deformation D3, and dynamic metamorphism (M3). This deformation is a progressive deformation that hasproduced the current morphologyof the Sanandaj-Sirjan zone (Shabanian Borujeni, 2008).
In this paper we focused on petrography and mineral chemistry and thermodynamic conditions of the metapelites.

Materials and methods
The chemical compositions of minerals were determined by a CAMECA SX100 electron microprobe (EMP) at Universität Stuttgart (Germany). The instrument is equipped with five wavelength dispersive spectrometers. The beam current and acceleration voltage were 15 nA and 15 kV, respectively.
v Discussion and Results
The Azna regional metamorphic rocks include quartz-feldspar schists, mica schists, andalusite-bearing schists and quartzites.
The Azna metapelites are schists, containing quartz, feldspars, andalusite, muscovite, biotite, muscovite, chlorite and garnet, in variable proportions, characterized byporphyroblastic and lepidoblastic textures. Based on mineralogy, minerals of these rocks contain andalusite, garnet, feldspar, muscovite, biotite, quartz and chlorite. Microprobe analyses show that the mineral compositions are as follows: White micas in the andalusite-bearing schists are muscovite, plagioclases are albite-oligoclase, garnets are almandine-spessartine with weak chemical zoning and biotites are siderophylite-annite.
Based on geothermobarometry, these rocks formed in the hornblende-hornfels facies and the low pressure part of the amphibolite facies,with temperatures about 562-692 °C and pressures1.07-4.12 kbar. After the regional metamorphism of these rocks,granitoidintrusions causedthermal metamorphism of these rocks and the formation of andalusite-bearing schists.

Acknowledgments
The authors wish to thank the Office of Graduate Studies of the University of Isfahan for their support. We also thank Prof. Hans-JoachimMassonne, who played major roles during the microprobe analysis of minerals at the InstitutfürMineralogie und Kristallchemie, Universität Stuttgart (Germany).

References
Aghanabati, A., 2004. Geology of Iran. Geological Survay of Iran, Tehran, Iran, 586 pp (in Persian).
Alavi, M., 1994. Tectonics of the Zagros Orogenic Belt of Iran: New Data and Interpretations. Tectonophysics, 22(1): 211–238.
Ghasemi, A. and Talbot, C.J., 2005. A new tectonic scenario for the Sanandaj-Sirjan Zone (Iran). Journal of Asian Earth Scines, 5(1):1-11.
Mohajjel, M. and Fergusson, C.L., 2000. Dextral transpression in Late Cretaceous contatinetal collision, Sanandaj-Sirjan Zone (Western Iran). Journal of Structural Geology, 22(1): 1125-1139.
Mohajjel, M., Fergusson, C.L. and Sahandi, M.R., 2003. Cretaceous-Tertiary contatinetal collision, Sanandaj- Sirjan Zone, Western Iran. Journal of Asian Earth Sciences, 21(1): 397-412.
Shabanian borujeni, N., 2008. Petrology and tectonic setting of the Azna granitoid masses (Sanandaj-Sirjan Zone, Iran). Ph.D. Thesis, University of Isfahan, Iran, 192 pp.

181-199

Authors: Mohammad Kashkoei Jahroomi; Afshin Qishlaqi

Introduction
In remote sensing studies, especially those in which multi-spectral image data are used, (i.e., Landsat-7 Enhanced Thematic Mapper), various statistical methods are often applied for image enhancement and feature extraction (Reddy, 2008). Principal component analysis is a multivariate statistical technique which is frequently used in multidimensional data analysis. This method attempts to extract and place the spectral information into a smaller set of new components that are more interpretable. However, the results obtained from this method are not so straightforward and require somewhat sophisticated techniques to interpret (Drury, 2001). In this paper we present a new approach for mapping of hydrothermal alteration by analyzing and selecting the principal components extracted through processing of Landsat ETM+ images.
The study area is located in a mountainous region of southern Kerman. Geologically, it lies in the volcanic belt of central Iran adjacent to the Gogher-Baft ophiolite zone. The region is highly altered with sericitic, propyliticand argillic alterationwell developed, and argillic alteration is limited (Jafari, 2009; Masumi and Ranjbar, 2011). Multispectral data of Landsat ETM+ was acquired (path 181, row 34) in this study. In these images the color composites of Band 7, Band 4 and Band 1 in RGB indicate the lithology outcropping in the study area. The principal component analysis (PCA) ofimage data is often implemented computationally using three steps: (1) Calculation of the variance, covariance matrix or correlation matrix of the satellite sensor data. (2) Computation of the eigenvalues and eigenvectors of the variance-covariance matrix or correlation matrix, and (3) Linear transformation of the image data using the coefficients of the eigenvector matrix.

Results
By applying PCA to the spectral data, according to the eigenvectors obtained, 6 principal components were extracted from the data set. In the PCA matrix, theeigen vector differences between the means of the level of significance between two bands (or spectral significance of the PC). The higher value is regarded as the Target Value of the bands which show a lower correlation. The components having maximum spectral significance of PCs, in bands 1 and 3, 5 and 7 and 5 and 3, were selected for enhancement of iron oxides, clay minerals and carbonate minerals, respectively. In each PC matrix, the sum of the significances is regarded as the spectral weight of that PC.
The spectral weight of the extracted PCs, was found to be as follows:
PC5> PC4>PC2>PC3>PC7>PC1
The inverse PC4 and –PC3 provide valuable information on vegetation mapping. In order to map the alteration zones and igneous rocks outcropped in the study area, the color composites of the PC5, -PC4 and average of each PC are included in RGB, respectively. The spectral proportion of each PC pertaining to each mineral was calculated as spectral significance in the two bands (e.g. Bands 5 and 7 for clay minerals and Bands 3 and 1 for Fe oxide minerals) divided by spectral weight of that PC. Based on the obtained results, the selectivity of the extracted components for enhancement of clay minerals and Fe oxide minerals was calculated and images of these minerals were produced using the following expressions:
Fe oxide minerals:
Clay minerals:
For carbonate minerals, the proportion of each PC is calculated in terms of the eigenvectors of bands 5 and 3. The selectivity of the PCs used in enhancing of spectral data of carbonate minerals is as follows: PC5>PC2>PC1>PC3>PC4>PC7
In the remotely sensed image, PC5 with high spectral weight was selected as the informative PC for clay minerals, iron oxides and carbonate minerals. This is becausepropylitic alteration and the formation of carbonate minerals can be easily enhanced in the processed images. Eventually, overlapping of the processed images provides patterns of hydrothermal alterationwhich indicate the areas to be prospected. In order to validate the obtained results of the image processing with geological evidence,petrographic studies of rock samples collected from major outcrops in the study area were made. It was found that quartz, calcite, epidote, sericite and chlorite are the main constituents of sericiticand propylitic alteration assemblages in the study area. The minerals are virtually enhanced in Landsat ETM+ using the proposed methods and confirm the results obtained from multispectral data analysis.

Conclusion
This study provides a new and improved approach to obtain the most meaningful spectral data for oxides, carbonates and clay minerals in multispectral images. As these minerals are typically found in hydrothermal alteration, the method presented in this article can be used for enhancement of such mineral spectral data, which can be very helpful in prospecting and exploration for hidden mineral deposits.

Acknowledgments
The first author wishes to sincerely thank Z.Gholami (PhD student, Shiraz University) for her assistance during this study. Also, we would like to thank Dr.Ranjabar (ShahidBahonar University of Kerman) and Dr. H.Tangestani (Shiraz University) for their constructive comments. Financial support for this study was provided by the ZABPAK Company.

References
Drury, S.A., 2001. Image interpretation in geology. Routledge, London, 304 pp.
Jafari, H., 2009. Evaluate the economic potential of copper in Hararan (Kerman province) using by lithogeochemical methods. Journal of Land and Resources, 1(2): 25-31.
Masumi, F. and Ranjbar, H., 2011. Hydrothermal alteration mapping using image sensors ASTER and ETM+ in the northern half of the Geological Map 1:100,000 Baft. Journal of Earth Sciences, 20(79): 121-128.
Reddy, M.A., 2008. Textbook of Remote Sensing and Geographical Information Systems. Atlantic Publishers and Distributors, Haydarabad, 476 pp.

223-238

Authors: Seyed Abolfazl Ezzati; Seyed Reza Mehrnia; Kimiya Sadat Ajayebi

Introduction
The Ramand area, southwest of Buin- Zahra, about 60 kilometers from Qazvin, lies in the igneous belt of the Urmieh-Dokhtar region, the main structural zone of north-central Iran. Rhyodacite and rhyolite lava flows are the principal host rocks of mineralization and alteration of the area, most of which occurs in faulted and brecciated zones alongmaj or northwest-trending fault systems (such as Kour-Cheshmeh, Hassan Abad and their branches). Clay minerals determined from satellite images indicated principally argillic hydrothermal alteration before laboratory mineralogical analysis. According to instrumental analyses, mineralized alteration with greater amounts of argillic halos and lesser amounts of sericitic-propylitic minerals contains quartz veinlets in the vertical and lateral sections. Initially, alteration in the Ramand area was revealed in ETM images by using the SPCA technique of Crosta and Moore, 1990 (Selective Principle Component Analysis). Compared with other techniques, SPCA results have reliable spectral signatures for identifying argillic minerals and Fe-oxides as the main mineralogical association in hydrothermal environments. Subsequently, multispectral images (ASTER) were analyzed using band ratios.The results indicated silicification alteration along the faulted regions in the Ramand area. Later, areas of silicification alteration were prospected for precious and base metal mineralization.Sampling results suggested that the altered areas have some potential for epithermal mineralization, according to instrumental analyses and micrographic evidence.

Materials and methods
1- Collecting satellite images, geological evidence and related documents
2- Image processing to reveal and identify the mineralized alteration.
3- Sampling of the mineralized zones indicated by the remote sensing.
4- Thin- and polished section microscopic studies. 5- X-ray diffraction analysis (XRD) (19 samples), inductively coupled plasma mass spectrometry analysis(ICP- MS)for determining the major and trace elements (4 samples) and 4 samples were analyzed for the gold content by using atomic absorption (AA).

Discussion and results
Most of the hydrothermal alteration in the Ramand region was mapped by processing the ETM and ASTER satellite images. The Crosta and Moore (1990) technique indicated the facies of alteration, and increased the correlation between altered and mineralized regions.
Evaluating the potential for ore-grade mineralization requires mapping the location and probable zonal location of the quartz veins indicated by band ratios in the ASTER image (Kruse et al., 1993; Honarmand et al., 2012). Our studies showed that volcanic rocks in the Ramand area are intensively altered by hydrothermal processes. The micrographic results confirmed that argillic and silicification alteration occurred within calcitized-oxidized masses. The study has shown that the mineralized region significantly contains quartz veinlets usually surrounded by argillic halos and Fe-oxides as two components of the alteration.
In conclusion, our remotely sensed prognostic mapindicates a strongly altered epithermal system along faulted structures and breccia zonesclearly apparent at the surface (Akbari, et al., 2012).The altered zones probably extend at depth with probable zones enriched in gold and base metals. Considering the zonalpatterns indicated by image processing, besides the ore genesis peculiarities of the epithermal systems (micrographic results), this article introduces reliable data indicating the nature of mineralization in the Ramand area based on analysis of satellite images and mineralogical and chemical analyses of samples which encourage detailed exploration for discovery of orebodies in a deeper prospect.

References
Akbari, A., Mehrnia, S.R. and Moghadasi, J., 2012. Using GIS for Investigating on Barite Mineralization Potentials in Qazvin 1/100000 Sheet. 6th National Geological Conference, Payame Noor University of Kerman, Kerman, Iran (in Persian with English abstract).
Crosta, A.P. and Moore, J.McM., 1990. Enhancement of Landsat thematic mapper imagery for residual soil mapping in SW Minais Gerais State, Brazil: a prospecting case history in Greenstone belt terrain. 7th Thematic Conference on Remote Sensing for Exploration Geology, University ofCalgary, Calgary Canada.
Honarmand, M., Ranjbar, H. and Shahabpour, J., 2012.Application of principal component analysis and spectral angle mapper in the mapping of hydrothermal alteration in the Jebal–Barez Area, Southeastern Iran. Resource Geology, 62(2): 119–139.
Kruse, F.A., Lefkoff A.B., Boardman, J.W., Heidebrecht, K.B., Shapiro, A.T., Barloon, P.J. and Goetz. A.F.H., 1993. The spectral image processing system interactive visualization and analysis of imaging spectrometer data. Remote Sensing of Environment, Elsevier, 44(2-3): 145-163.

265*282

Authors: Sedigheh Zirjanizadeh; Mohammad Hassan Karimpour; Khosrow Ebrahimi Nasrabadi; Jose Francisco Santos

Introduction
The study area is located in NW Gonabad, Razavi Khorasan Province, northern Lut block and eastern Iran north of the Lut Block. Magmatism in NW Gonabad produced plutonic and volcanic rock associations with varying geochemical compositions. These rocks are related to the Cenozoic magmatic rocks in Iran and belong to the Lut Block volcanic–plutonic belt. In this study, petrogenesis of volcanic units in northwest Gonabad was investigated.
The volcanic rocks are andesites/trachyandesites, rhyolites, dacites/ rhyodacites and pyroclastics.These rocks show porphyritic, trachytic and embayed textures in phenocrysts with plagioclase, sanidine and quartz (most notably in dacite and rhyolite), hornblende and rare biotite. The most important alteration zones are propylitic, silicification and argillic.Four kaolinite- bearing clay deposits have been located in areas affectedby hydrothermal alteration of Eocene rhyolite, dacite and rhyodacite.

Analytical techniques
Five samples were analyzed for major elements by wavelength dispersive X-ray fluorescence (XRF) and six samples were analyzed for trace elements using inductively coupled plasma-mass spectrometry (ICP-MS) in the Acme Laboratories, Vancouver (Canada).Sr and Nd isotopic compositions were determined for four whole-rock samples at the Laboratório de GeologiaIsotópica da Universidade de Aveiro, Portugal.

Results
Petrography. The rocks in this area are consist of trachyte, andesite/ trachyandesite, dacite/ rhyodacite, principally as ignimbrites and soft tuff. The textures of phenocrysts are mainly porphyritic, glomerophyric, trachytic and embayed textures in plagioclase, hornblende and biotite. The groundmasses consist of plagioclase and fine-grainedcrystals of hornblende. Plagioclase phenocrysts and microlitesare by far the most abundant textures in andesite - trachyandesites (>25% and in size from 0.01 to 0.1mm). Euhedral to subhedral hornblende phenocrysts areabundant (3-5%)and 0.1 to 0.6mmin size.
Trachyte is characterized by trachytic texture. Ninety percent of the rock consists of sanidine. In trachytes, 3 to 5% hornblende ( 0.3 mm) is replaced by carbonates. Rhyolites contain quartz, plagioclase, sanidine, and biotite phenocrysts in a microcrystalline to glassy groundmass. Rhyodacitehas phenocrysts, some glomerophyric, consisting of quartz, 2 to 3% (0.1-0.5 mm), plagioclase 7 to 10% (0.2- 0.8 mm), hornblende 5% and biotite 1%. Up to 15% of sanidineis altered to clay minerals. Crystal tuff and lithic-crystal tuff are distributed overa large area.
Using the Zr/TiO2 and Nb/Y diagram of Winchester and Fold (1977), samples are designated as rhyolite, dacite and sub-alkaline basalt. In the Co vs. Th diagram of Hastie et al. (2007), samples plot in the shoshonitic and high calc-alkaline, rhyolite, dacite and andesite-basalt fields.
The REE patterns and trace element contents of the volcanic samples show: (1) LREE/HREE enrichment ((La/Yb) N = 0.3 to 15.27), (2) Low negative Eu anomaly (ave.Eu*/Eu=0.2-0.85), (3) depletion in Ba, Sr, K2O, Zr and Ti (Lower continental crust-normalized spider diagram from Taylor and McLennan, 1985 and Chondrite-normalized diagram from Nakamura, 1974. Rhyolites show the most extreme negative Eu anomaly (Eu/Eu* = 0.2-0.3) compared with 0.65–0.85 for volcanic elsewhere and also show considerably differences in the contents of Rb,Sr,K,Ti,Zr,Hf,Ce. These differences are related to greater magmatic differentiation or derivation from the other sources. The Sr and Nd isotopic ratios of these volcanic rocks are: 87Sr/86Sr = 0.70699 to 0.71014 and 143Nd/144Nd =0.512144 to 0.512539. Assuming an age of 60 Ma, the initial 87Sr/86Sr ratios vary from 0.70671 to 0.71066 and initial 143Nd/144Nd values vary from 0.512098 0.51249 (εNdi = -9.1) to 0.51249 (εNdi = -1.4).In the εNdi versus (87Sr/86Sr)i diagram, the samples plot in the field typical of magmas that are of crustal origin or, at least, that underwent important processes of crustal assimilation/contamination.
Andesitic rocks displays lightly lower rangesof87Sr/86Sr (0.7067-0.7068) and εNdi values from -1.44 to -2.34, than rhyolite. Distinct Sr and Nd isotopic compositions are seen between rhyolitic rocks and andesitic rocks. The geochemical data suggest that the rhyolitic magmas probably represent the final differentiates of parental magmas, resulting from partial melting of mafic lower crust. Generally, the magmas from this area have low Sr (less than 400 ppm), high K2O/Na2O and negative Eu anomalies.

References
Hastie, A.R., Kerr, A.C., Pearce, J.A. and Mitchell, S.F., 2007. Classification of altered volcanic island arc rocks using immobile trace elements: development of the Th-Co discrimination diagram. Journal of Petrology, 48(12): 2341- 2357.
Nakamura, N., 1974. Determination of REE, Ba, Fe, Mg, Na, and K in carbonaceous and ordinary chondrites. Geochim, Cosmochim, Acta, 38(5): 757–775.
Taylor, S.R. and McLennan, S.M., 1985. The continental crust, its composition and evolution, an examination of the geochemical record preserved in sedimentary rocks. Blackwell, Oxford, 312 pp.
Winchester, J.A. and Floyd, P.A., 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology, 20(4): 325-343.