Journal of Economic Geology

179-202

Authors: Mohammad Ali Jazi, Mohammad Hassan Karimpour and Azadeh Malekzadeh Shafaroudi

Introduction
The Baqoroq Cu-Zn-As deposit is located northeast of the town ofAnarak in Isfahan province, in theeast central areaof Iran. Copper mineralization occursin upper cretaceous carbonate rocks.Studyof thegeologyof the Nakhlak area, the location ofa carbonate-hosted base metaldeposit, indicatesthe importance of stratigraphic, lithological and structural controls in the placement of this ore deposit. (Jazi et al., 2015).Some of the most world’s most important epigenetic, stratabound and discordant copperdeposits are the carbonate hosted Tsumeb and Kipushi type deposits,located in Africa. The Baqoroq deposit is believed to be of this type.

Materials and methods
In the current study, fifty rock samples were collected from old tunnels and surface mineralization. Twenty-two thin sections, ten polished sections and four thin-polished sections were prepared for microscopic study. Ten samples were selected for elemental analysis by ICP-OES (Inductively coupled plasma optical emission spectrometry) by the Zar Azma Company (Tehran) and AAS (Atomic absorption spectrometry) at the Ferdowsi University of Mashhad. Seven doubly polished sections of barite mineralization were prepared for microthermometric analysis. Homogenization and last ice-melting temperatures were measured using a Linkam THMSG 600 combined heating and freezing stage at Ferdowsi University of Mashhad. Sulfur isotopes of five barite samples were determined by the Iso-Analytical Ltd. Company of the UK. The isotopic ratios are presented in per mil (‰)notation relative to the Canyon Diablo Troilite.

Results
The upper Cretaceoushost rocks of the Baqoroq deposit include limestone, sandstone, and conglomerate units. Mineralization is controlled by two main factors: lithostratigraphy and structure. Epigenetic Cu-Zn mineralizationoccurs in ore zones as stratabound barite and barite-calcite veins and minor disseminated mineralization. Open space filling occurred as breccia matrix, crustification banding,andbotryoidaltexture. The host rock has undergone dolomitization alteration Hypogene minerals include chalcopyrite, pyrite, sphalerite, galena, enargite, barite, and calcite. Supergene minerals include malachite, azurite, covellite, chrysocolla, chalcocite, cerussite, smithsonite, native copper and iron oxide minerals. Sulfantimonides and sulfardenides are abundant in low- and moderate temperature stages of the deposit, while bismuth sulfides generally occur in higher temperature ores, according to Malakhov, 1968.
Analysis of rich ore samples indicates copper is the most abundant heavy metal in the ore (average 20.28 wt%), followed by zinc (average ~ 1 wt%) and arsenic (average ~ 1 wt%), respectively. Thepresence of many trace elements in the ore, such as Sb, Pb, Ag and V, are very important. Element pairs such as Ag-Cu, Zn-Cd, Zn-Sb, Fe-V and Pb-Mo are correlated with each other. The Baqoroq ore minerals are rich in As, Sb and poor in Bi. Highamountsof antimony usually occur in a low temperature stage (Marshall and Joensuu, 1961). Malakhov (1968) suggested thata high Sb/Biratio in the ore indicates a low temperature of formation for the Baqoroq deposit. Sulfide mineralization fluids were found to have homogenization temperatures between 259 and 354°C and salinities between 8.37 and 13.18 wt% NaCl eq. Surface water apparently diluted theore-bearing fluids in the final stages and deposited sulfide-freecalcite veins at relatively low temperatures (78 to 112 °C) and low salinities (3.59 to 6.07 wt% NaCl eq.).
The δ34S values of barite of the Baqoroq deposit range from +13.1 to +14.37‰from whichδ34S values of ore fluids were calculated to vary between -8.57‰ and -7.23‰. Sulfur within natural environments is derived ultimately from either igneous or seawater sources (Ohmoto and Rye, 1979). Barite δ34S values of Baqoroq deposit lie within the range of Cretaceous-age oceanic sulfate values. The reduction of sulfate to sulfide couldhave been caused either by bacterial sulfate reduction or by nonbacterial sulfate reduction through a reaction with organic materialin the sedimentary rocks (thermochemical sulfate reduction). However, the narrow range of δ34S and positive values indicates that they were not produced by bacterial sulfate reduction.Partial thermochemical reduction of sulfates has apparently produced light sulfurvalues (~ 21‰ lighter) and it has been effective inthe deposition of ore minerals. Organic matter occurs as graphite in the Baqoroq formation in proximity of Baqoroq deposit (Cherepovsky et al., 1982).

Discussion
Epigenetic, stratabound and discordant Cu-Zn-As mineralization in the Baqoroq deposit occurs as open space filling of upper Cretaceous rocks. Host rock is partially dolomitized by ascending warm, saline fluids. Seawater sulfates were the source of the sulfidesulfur and the sulfate in the barite. The reduced sulfur was generated by partial thermochemical reduction and it was effective inthe deposition ofthe ore minerals. Based onthe evidence of carbonate host rocks, the absence of igneous activity, the open space filling texture, mineralogy, dolomite alteration, ore geochemistry (As and Sb high content and absence of Bi), microthermometric data of ore bearing fluid and sulfur isotope values, the Baqoroq deposit is very similar to the carbonate hosted copper deposits in Africa and in particular the Tsumeb deposit in Namibia. The Baqoroqdepositmay have been produced bymetamorphicfluids during orogenyrelated to theclosureof the Neo-Tethys ocean.

References
Cherepovsky, N., Plyaskin, V., Zhitinev, N., Kokorin, Y., Susov, M., Melnikov, B. and Aistov, L., 1982. Report on detailed geological prospecting in Anarak area (Central Iran) Nakhlak locality. Geological Survey of Iran and Technoexport Company, Tehran. Report 14, 196 pp.
Jazi, M.A., Karimpour, M.H., Malekzadeh, A. and Rahimi, B., 2015. Stratigraphic, lithological and structural controls in placement of Nakhlak deposit (northeast of Esfahan). Advanced Applied Geology, 15(1): 59-75. (in Persian with English abstract)
Malakhov, A.A., 1968. Bismuth and antimony in galena as indicators of some conditions of ore formation. Geochemistry International, 7(11): 1055-1068.
Marshall, R.R. and Joensuu, O., 1961. Crystal habit and trace element content of some galena. Economic Geology, 56(4): 758-771. Ohmoto, H. and Rye, R.O., 1979. Isotopes of sulphur and carbon. In: H.L. Barnes (Editor), Geochemistry of Hydrothermal Ore Deposits. Wiley-Interscience, New York, pp. 509-567.

225-241

Authors: Fereshteh Bayat and Ghodrat Torabi

Introduction
The occurrence of blueschist metamorphic facies is believed to mark the existence of former subduction zones. This facies is represented in the main constituents of subduction-accretion complexes, where it occurs in separate tectonic sheets, imbricated slices, lenses, or exotic blocks within a serpentinite mélange (Volkova et al., 2011). The evidence of the presence and maturity of Paleo- Tethys oceanic crust in the CEIM (define this) in Paleo-Tethys branches, subduction and collision has been studied by various authors (Bagheri, 2007; Zanchi et al., 2009; Bayat and Torabi, 2011; Torabi 2011). Late Paleozoic blueschists have recognized in the western part of the CEIM (e. g. Anarak, Chupanan and Turkmeni) in linear trends. Metamorphic rocks of the Turkmeni area (SE of Anarak) are composed of blueschist and meta-greywacke and are situated along the Turkmeni-Ordib fault associated with Paleozoic rock units and serpentinized peridotite bodies. Turkmeni blueschist and meta-greywackes have not been studied by previous workers.
The Turkmeni blueschists consist of albite, winchite, actinolite and epidote. Granoblastic, nematoblastic and lepidoblastic are main textures in these rocks. Winchite is found in the matrix and around epidote grains. This sodic-calcic amphibole serves as an index mineral in blueschist facies. Actinolite and epidote formed during retrograde metamorphism of blueschists in the greenschist facies. The mineral assemblage of albite, epidote, chlorite and phengite ± garnet is present in meta-greywackes in the Turkmeni blueschists. Veins of garnet, muscovite, quartz and opaque minerals are extensive in these rocks. Epidote and chlorite formed in meta-greywackes by retrograde metamorphism in the greenschist facies. The aim of the present study is to determine the petrological and geochemical characteristics, P-T condition of blueschists and meta-greywackes, as well as the geotectonic setting of primary basaltic rocks of the Turkmeni blueschists.

Material and methods
This study is based on field observations and petrographical and analytical studies. Satellite images and a geological map were prepared. About 20 thin sections were supplied for petrological studies. Mineral chemical analyses were carried out by a JEOL JXA-8800R electron probe micro-analyzer (EPMA) at the Cooperative Center of Kanazawa University, Japan. The analyses were performed under an accelerating voltage of 15 kV and a beam current of 15 nA with 3µm probe beam diameter. The Fe3+ contents of minerals were estimated by assuming ideal mineral stoichiometry. The representative mineral compositions are given in Tables 1-3. Major oxides, rare earth elements (REE) and trace elements of five blueschists samples were analyzed by the ICP-MS method (Kanpanzhouh Research Company, Tehran, Iran) of the SGS laboratory of Canada. Whole rock chemical data are presented in Table 4.

Results and discussion
Petrographical and geochemical characteristics of Turkmeni blueschists reveal that they were derived from a similar mantle source and underwent analogous melt extraction and post magmatism occurrences. According to the trace and rare earth elements contents, the protolith of blueschists should be formed by crystallization of tholeiitic basalt and have sub-alkali basalt nature. Blueschists have LREE values more than HREE. High amounts and evident variations of LIL elements are obvious. Negative anomalies of HFSE such as Nb, Hf, Zr and Ti are evident in Turkmeni blueschist. REE trends of these rocks resemble as the back arc basin basalts. Based on the Nb/La ratio and REE contents, the original magma has been generated by low to medium degree of partial melting of a lithospheric mantle spinel lherzolite. Geochemical characteristics and normalized diagrams reveal that primary magma of protolith has been nature near to IAB and E-MORB. The related processes to subduction of Paleo-Tethys oceanic crust led to mantle enrichment and carbonate metasomatism. The Paleo-Tethys Ocean spreading in CEIM commenced in Late Ordovician and terminated in the Late Paleozoic-Triassic. Association of meta-greywackes with blueschist and LILE/HFSE contents shows that Paleo-Tethys oceanic crust subduction zone at Turkmeni region was been immature. Mineral chemistry and assemblages of the blueschists and meta-greywackes units reveal that they suffered different metamorphic evolution: (M1) greenschist metamorphism by existence of actinolite and albite in basaltic rocks, and then they passed a prograde metamorphism in the blueschist facies by existence of winchites (M2) which is followed by a retrograde metamorphism P-T condition in the greenschist facies (M3). Variscan tectono-metamorphism occurrence has been main metamorphic phase in Anarak region and it has led to metamorphism in blueschist facies of Turkmeni rocks.

Acknowledgments
The authors wish to thank the University of Isfahan University for financial supports.

Reference
Bagheri, S., 2007.The exotic Paleo-tethys terrane in Central Iran: new geological data from Anarak, Jandaq and Posht-e-Badam areas. Ph.D. thesis, Faculty of Geosciences and Environment. University of Lausanne, Switzerland, 208 pp.
Bayat, F. and Torabi, G., 2011. Alkaline lamprophyric province of Central Iran, Island Arc, 20(3): 386-400.
Torabi, G., 2011. Late Permian blueschist from Anarak ophiolite (Central Iran, Isfahan province), a mark of multi-suture closure of the Paleo-Tethys ocean. Revista Mexicana de Ciencias Geológicas, 28(3): 544-554.
Volkova, N.I., Travin, A.V. and Yudin, D.S., 2011. Ordovician blueschist metamorphism as a reflection of accretion-collision events in the Central Asian orogenic belt. Russian Geology and Geophysics, 52(1): 72-84.
Zanchi, A., Zanchetta, S., Garzanti, E., Balini, M., Berra, F., Mattei, M. and Muttoni, G., 2009. The Cimmerian evolution of the Nakhlak – Anarak area, Central Iran, and its bearing for the reconstruction of the history of the Eurasian margin. Geological Society, London, Special Publications, 312: 261-286.

259-276

Authors: Mohammad Ali Rajabzadeh and Fatemeh Al Sadi

Introduction
Worldwide, Ni-Cu and PGE magmatic sulfide deposits are confined to the lower parts of stratiform mafic and ultramafic complexes. However, ophiolite mafic and ultramafic complexes have been rarely explored for sulfide deposits despite the fact that they have been extensively explored and exploited for chromite. Sulfide saturation during magmatic evolution is necessary for sulfide mineralization, in which sulfide melts scavenge chalcophile metals from the parent magma and concentrate them in specific lithological zones. The lack of exploration for sulfides in this environment suggests that sulfide saturation is rarely attained in ophiolite-related magmas. Some ophiolites, however, contain sulfide deposits, such as at Acoje in Philippines, and Cliffs in Shetland, U.K. (Evans, 2000; Naldrett, 2004). The Faryab ophiolite complex in southern Kerman Province, the most important mining area for chromite deposits in Iran, is located in the southwest part of the Makran Zone. Evidence of sulfide mineralization has been reported there by some authors (e.g. Rajabzadeh and Moosavinasab, 2013). This paper discusses the genesis of sulfides in the Faryab ophiolite using mineral chemistry of the major mineral phases in different rocks of the ophiolite column in order to determine the possible lithological location of sulfide deposits.

Materials and methods
Seventy three rock samples from cumulate units were collected from surficial occurrences and drill core. The samples were studied using conventional microscopic methods and the mineralogy confirmed by x-ray diffraction. Electron microprobe analysis was carried out on different mineral phases in order to determine the chemistry of the minerals used in the interpretation of magma evolution in the Faryab ophiolite.
Lithologically, the Faryab ophiolite complex is divided into two major parts: the northern part includes magmatic rocks and the southern part is comprised of rocks residual after partial melting of the upper mantle. Sulfide mineralization in the complex is confined to cumulate rocks in northern part of ophiolite column. The mineralization is olivine-rich clinopyroxene and wehrlite. Petrographic investigation of sulfides in host ultramafics indicated two sulfide generations. In the first generation, primary magmatic sulfides occurred as interstitial disseminations, generally as anhedral grains. In the second generation, sulfides formed as veinlets along host rock fractures. The primary sulfides include pyrrhotite, pentlandite, and secondary digenite and pyrite. The primary sulfide content increases with increasing size and amount of clinopyroxene in host rocks. Associated chromian spinels in host ultramafics display disseminated and massive textures.

Discussion
Generally, mineralization in ophiolites is controlled by two major steps: a) partial melting of upper mantle rocks and b) crystal fractionation in a magma chamber (Rajabzadeh and Moosavinasab, 2013). The chemical compositions of the analyzed minerals were then used in estimating the conditions in these two steps. The composition of chromian spinel corresponds to chromite of boninitic melts formed in supra-subduction zone environments. Boninitic melts are produced at high degrees of partial melting of mantle peridotites in the presence of water (Edwards et al., 2002). Silicates of the host rocks are mainly clinopyroxene (diopside and augite) of the composition Wo47.50 En45.48 Fs3.4, olivine Fo92 and orthopyroxene (enstatite - bronzite) of En85 to En88. The main host ultramafic rocks of sulfides are wehrlite and clinopyroxenite, indicating that the sulfide saturation occurred during magmatic evolution of these rocks. This suggests that sulfide mineralization will occur in the northern part the ophiolite. The sulfide grains are anhedral, amoeboidal in shape, and appeared as disseminated interstitial phases, indicating that they were trapped as liquid phases during increase in sulfur fugacity and decrease in FeO content and temperature of crystallization of clinopyroxene-rich rocks (Talkington et al., 1984; Von Gruenewaldt et al., 1990). Nickel-rich pentlandite is the main sulfide in the Faryab complex. The composition of this is mineral is consistent with the crystallization in an equilibrium condition (Song et al., 2008). The sulfide may have been introduced from external sources during upward movement and emplacement of parent magma.

Acknowledgments
The authors are grateful to the Research Council of Shiraz University for financially supporting this study.

References
Edwards, S.J., Pearce, J.A. and Freeman, J., 2002. New insights concerning the influence of water during the formation of podiform chromitite. Geological Society of America, Special Paper, 349 (3) 139-147.
Evans, A.M., 2000. Ore geology and industrial minerals. An Introduction. Black well Pub, Oxford, London, 389 pp.
Naldrett, A.J., 2004. Magmatic Sulfide Deposits: Geology, Geochemistry and Exploration. Springer, New York, 727 pp.
Rajabzadeh, M.A., Moosavinasab, Z., 2013. Mineralogy and distribution of Platinum-Group-Minerals (PGM) and other solid inclusions in the Faryab ophiolitic chromitites, Southern Iran. Mineralogy and Petrology, 107 (6): 943-962.
Song, X., Zhou M., Tao Y., and Xia, J., 2008. Controls on the metal compositions of magmatic sulfide deposits in the Emeishan large igneous province, SW China. Chemical Geology, 253 (1-2): 38-49.
Talkington, R.W., Watkinson, D.H, Whittaker P.J., Jones P.C., 1984. Platinum group minerals and other solide inclusions in chromite of ophiolitic complexes: occurrences and petrological significance. Tschermakes Mineralogische und Petrographische Mitteilungen, 32 (4): 285-301.
Von Gruenewaldt, G., Dicks, D., Wet J. and Horsch, H., 1990. PGE mineralization in the western sector of the Eastern Bushveld complex. Mineralogy and Petrology, 42 (1): 71-95.

307-325

Authors: Arash Gorabjeiri Puor and Mohsen Mobasheri

Introduction
The Mahour exploration area is a polymetallic system containing copper, zinc and silver. The mineralization can be seen in two forms of veins and disseminations. This area is structurally within the Lut block, west of Deh-salm Village. Recent exploration work and studies carried out by geologists on this volcanic-plutonic area of Lut demonstate its importance indicating new reserves of copper, gold, and lead and zinc.
Several articles have been published on the Mahour deposit in recent years, including work on fluid inclusions (Mirzaei et al., 2012a; Mirzaei et al., 2012b).
The present report aims at completion of previous studies on Mahour. During the course of this research, the IP/RS geophysical methods were used to locate the extent and depth of sulfide veins in order to locate drill sites. The IP/RS method has been used extensively worldwide in locating sulfide mineralization at deposits such as Olympic Dam in Australia (Esdale et al., 1987), Hishikari epithermal gold deposit in Kagoshima, Japan (Okada, 1995) and Cadia-Ridgeway copper and gold deposit in New South Wales, Australia (Rutley et al., 2001).

Materials and Methods
1. Determination of mineralogy of ore and alteration by examination of 70 thin sections and 45 polished sections.
2. Compilation of geological and mineralization maps of the studied area at a scale of 1:1000.
3. Geological, alteration, mineralization and trace element geochemical studies of 6 drill holes.
4. IP/RS measurements for 2585 points on a rectangular grid with profile intervals of 50 meters and electrode intervals of 20 meters.
5. Interpretation of IP/RS results.

Discussion
The Mahour area is covered by a volcanic sequence of basalt, andesite, dacite, rhyolite and pyro-clastics. During the Late Eocene through Early Oligocene this volcanic complex was intruded by several diorite and quartz-diorite bodies, which were responsible for mineralization of the area. Mineralized veins hosted by dacite show NNE trends with 85 t0 90° dips, and which are accompanied by argillic, silicic, quartz-sericite-pyrite and propylitic alteration zones. The primary minerals include pyrite, chalcopyrite, sphalerite, galena, tetrahedrite, and quartz along with supergene minerals such as malachite, atacamite, azurite and goethite. High anomalies of copper (up to 103062 ppm), zinc (up to 213520 ppm) and silver (up to 1988 ppm) are present in the studied area.
The IP/RS surveys were carried out on profiles perpendicular to the veins. The chargeability levels reached 40 msce, indicating the presence of sulfide minerals in the area. Two especially anomalous resistivity zones, high and low, were detected within the deposit. The high resistivity zone, up to 350 ohm.m, occurs along geophysical profiles in association with less-crushed zones, whereas the low anomaly zone is related to highly crushed zones.
The geophysical anomalies agree with drilling results indicating zones of highest mineralization.

Results
Generally, the chargeability surveys have clearly revealed two anomalous zones: one in the northeast and the other in the southwest of the studied area. Six holes have been drilled through these anomalous zones and geochemical samples taken at intervals of 1 meter in each hole. Most of the anomalies are associated with quartz-sericite-pyrite, silicification and chloritic alteration as well as the intense distribution of secondary iron oxides.
Geochemical results from the drill holes show the highest anomalies as follows:
GBH-1, 78-92 m, 246-281 m GBH-3 20-40 m and 133-152 m
GBH-7 20-32 m and 57-65m
PB-1 85-94 m. and 133-140 m
PD-1. 50-55 m, 298-301 m and 360-365 m
PA-1 48-57 m, 152-161 m and 212-218 m

References
Esdale, D.J., Pridmore, D.F., Coggen, J.H., Muir, P.M., Williams, P.K. and Fritz, F.P., 1987. Olympic Dam deposite- Geophysical case history. Journal of the Australian Society of Exploration Geophysics, 18(2): 47- 49. Mirzaei Rayni, R., Ahmadi, A. and Mirnejad, H., 2012a. The origin of ore-forming fluids in the Mahour polymetal ore deposit, using electron microprobe data and sulfur isotopes, East of Lut block, Central Iran. Journal of Petrology, 3(10): 1-12. (in Persian with English abstract)
Mirzaei Rayni, R., Ahmadi, A. and Mirnejad, H., 2012b. Study of mineralogy and fluid inclusions in the Mahour polymetal ore deposit, East of Lut block, Central Iran. Iranian Journal of Crystallography and Mineralogy, 20(2): 307-318.(in Persian)
Okada, K., 1995. Geophysical exploration for epithermal gold deposits: Case studies from the Hishikari gold mine, Kagoshima, Japan. Journal of the Australian Society of Exploration Geophysics, 26(3): 78- 83.
Rutley, A., Oldenburg, D.W. and Shekhtman, R., 2001. 2-D and 3-D IP/resistivity inversion for the interpretation of Isa-style targets. Journal of the Australian Society of Exploration Geophysics, 32(4): 156-159.

343-367

Authors: Mohammad Maanijou, Masoumeh Vafaei Zad and Farhad Aliani

Introduction
The Ahangaran Pb-Ag deposit is located in the Hamedan province, west Iran, 25 km southeast of the city of Malayer . . The deposit lies in the strongly folded Sanandaj-Sirjan tectonic zone, in which the ore bodies occur as thin lenses and layers. The host rocks of the deposit are Early Cretaceous carbonates and sandstones that are unconformably underlain by Jurassic rocks. Ore minerals include galena, pyrite, chalcopyrite, pyrrhotite and supergene iron oxide minerals. Gangue minerals consist of barite, dolomite, chlorite, calcite and quartz. The mineralization occurs as open-space fillings, veins, veinlets, disseminations, and massive replacements. Alteration consists of silicification, sericitization, and dolomitization. In this study, we carried out studies of mineralogy, microthermometry of fluid inclusions and sulfur isotopes to determine the source of sulfur and the physico-chemical conditions of formation.

Materials and methods
Seventy samples of different host rocks, alteration, and mineralization were collected from surface outcrops and different tunnels. Twenty of the samples were prepared for mineralogical studies at Tarbiat Modarres University in Tehran and 25 for petrological studies at the University of Bu-Ali Sina. Fluid-inclusion studies were done on 5 samples of quartz and calcite at Pouya Zamin Azin Company in Tehran using a Linkam THM 600 model heating-freezing stage (with a range of -196 to 480ºC). The accuracy and precision of the homogenization measurements are about ±1°C. Salinity estimates were determined from the last melting temperatures of ice, utilizing the equations by Bodnar and Vityk (1994) and for CO2 fluids using equations by Chen (1972). Nine samples of sulfides and barite were crushed and separated by handpicking under binocular microscope and powdered with agate mortar and pestle. About one gram of each sample was sent to the Stable Isotope and ICP/MS Laboratory of Queen’s University, Canada for sulfur isotope analysis. The sulfur isotopes in sulfides and sulfates were run on a Thermo Finnigan Delta Plus XP IRMS mass spectrometer. The analytical uncertainty for δ34S is ±0.2‰.

Results and Discussion
The main types of fluid inclusions in quartz and calcite are as follows: I: dominant liquid + less vapor (L+V); II: dominant vapor + less liquid (V + L); III: liquid + vapor+ CO2 (L+V+CO2 )(L+V)); IV: CO2 (L+V); V: liquid + vapor + sylvite (L+V+Sy). Homogenization temperatures of primary fluid inclusions indicate that mineralization occurred at temperatures ranging from 130 to 320 °C (ave., 200°C) and their salinites range from 10 to 15 wt % NaCl equiv. The temperatures and salinities of the mineralizing fluids of the Ahangaran deposit are similar to the Irish type Zn-Pb deposits, and suggest a similar origin. The δ34S values of pyrite and galena are within the range of -25.5 to +11.6 ‰ and -6.3 to -8.5 ‰, respectively and for barite are in the range of 26 to 27.2 ‰. These values indicate that the δ34SH2S values of fluids in that deposited the pyrite and galena are within the range of -6.4 to-2.9 ‰ and 9.4 to 27.9 ‰, respectively. The δ34S values of marine sulfate were 13 to 20 ‰ during the Cretaceous (Hoefs, 2009). The δ34S values of barite are near to that of marine sulfate in the Cretaceous which indicate that the sulfate of the barite may have a marine origin. On the other hand, the δ34SH2S values of galena lie within a narrow range, suggesting that the main source of sulfur may be from thermochemical sulfate reduction (TSR).

Acknowledgments
In this research, we thank Sormak Mines Company for its support during field work. We also thank Sormak Mines Managers, especially Mr. Khakbaz for his cooperation and support of this research. Parts of this research were supported by the research department of Bu-Ali Sina University. We also wish to express our appreciation of the isotopic analyses by Queen's University, Canada.

References
Bodnar, R.J. and Vityk, M.O., 1994. Interpretation of microthermometric data for H2O-NaCl fluid inclusion. In: B. De Vivo and M.L. Fezzotti (Editors), Fluid inclusions in minerals, Methods and Applications. Virginia Tech, Blacksburg, pp. 117-130.
Chen, H.S., 1972. The thermodynamics and composition of carbon dioxide hydrate. M.Sc. Thesis, Syracuse University, Syracuse, New York, 67 pp.
Hoefs, J. (translated by Alirezaei, S.), 2009. Stable Isotope Geochemistry. Springer Verlag, Berlin, 332 pp. (in Persian)

385-402

Authors: Alireza Zarasvandi, Babak Samani, Houshang Pourkaseb, Zahra Khorsandi and Yaghoub Jalili

Introduction
Two main principal aspects for the genesis of porphyry copper deposits have been determined. The first genetic model concerns the petrologic and geochemical processes and the other relates the genesis to crustal deformation and geodynamic conditions (Kesler, 1997). Recent studies (e.g., Padilla Garza et al., 2001) show that the generation and emplacement of porphyry copper deposits may not only be dependent on magmatic and hydrothermal processes, but also that the regional and local tectonic setting plays an important role. Therefore in determining the suitable setting for emplacement of copper and other porphyry intrusions, determination of location of partial melting of the lower crust, generation of batholiths, and their volatile-rich derivative intrusions in the crust seems to be necessary (Carranza and Hale, 2002). Almost all porphyry copper deposits in Iran are located in the Urumieh-Dokhtar magmatic belt. These deposits show distinct spatial and temporal relationship with Miocene granodiorite plutonic rocks emplaced along strike slip faults (Mehrabi et al., 2005). Accordingly, the tectonic setting of ore deposits seem to be the most important factor for regional exploration of porphyry copper systems (Vearncombe and Vearncombe, 1999). There are several methods for analysis of distribution of ore deposits. In this research the role of structural control in the spatial distribution of porphyry deposits has been studied using Fry and Fractal methods. Here, the Fry method is used as a complementary method for Fractal analysis.

Materials and methods
Fry analysis is a self-adaptive method that is used for point objects. Fry analysis offers a visual approach to quantify the spatial trends in groups of point objects. Fry analysis can also be used to search for anisotropies in the distribution of point objects. More specifically it can be used to investigate whether a distribution of point objects occurs along linear trends, and whether such linear trends occur at a characteristic spacing. There is 37 and 42 copper point's index in the Khezr-Abad and Shar-B-Babak areas. The Fry patterns of copper index for two areas were determined with application of Dot Proc software. Fractal analysis is another technique for determination of regional distribution of faults. In this research the fractal dimension of joints and faults was determined in different locations using box-counting fractal method and drawing the logarithmic graphs.

Results
- The major faults show NW/SE trends in the Khezr-Abad area. They have a similar trend with Dehshir-Baft fault. Other sets of faults show NE/SW trend. These faults are younger than the Dehshir-Baft and release sinistral sense of shear.
- Intrusion of two intrusive bodies leads to the accumulation of strike-slip faults in the vicinity of intrusive rocks. In this region faults and joints mainly show NW/SE and NE/SW trends.
- The results of Fry analysis show that the mineralization in the Khezr-Abad occurred in the Cretaceous (and younger) rocks with NE/SW and NW/SE orientations. In the other words, these areas of mineralization are mainly related to the secondary faults or (P faults) in the pull basins and cross cutting points of these faults which have similar strike with the Dehshir-Baft fault. NE/SW mineralization is probably related to the tensional stress direction or faults having the general trends of central Iran structures.
- The calculations of fractal dimension show that the southeastern parts of the Khezr Abad have higher amounts of fractal dimension (Db= 1.7002). Also there is a relatively higher copper index in this part, indicating a logical relation between fault structures and mineralization.
-The generated maps indicate that the mineralization in the Shahr-e-Babak area occurred at the intersection of faults and volcanic system and the Fry analysis shows a NE/SW and NW/SE trend of ore concentration.
- Northwestern parts of the Share-e-Babak show higher fractal dimension (Db= 1.748) that occurs in the areas with more volcanic rocks and copper indexes.
- Results show that the porphyry copper mineralization mainly occurs near the great faults and related to the fault structures and shear zones in the Urumieh-Dokhtar structural zone. In the other word fault lineaments are the main factors in the local concentration of the ore deposits.

Discussion
The Study of geometry and mechanism of faults related to porphyry copper deposits is very important for determining the suitable location of ore concentration (Zarasvandi, 2004). For example, shear zones, pull apart basins, and step over along the strike slip faults are proper locations for concentration of porphyry ore deposits (Carranza and Hale, 2002). In this research the Khezr-Abad and Shahr-e-Babak areas have been studied. Plotted rose diagrams show the main role of the Dehshir-Baft shear zone for generating the joints and faults in the KhezrAbad area. In this area faults with NNW/SSE and NW/SE trends are the main direction of ore concentration. They are mainly related to the Dehshir-Baft fault. NE/SW faults show sinistral sense of shear and generally are younger than before mentioned sets. Finally the latest fault sets show N/S trend. The Shahre-e-Babak area is mainly dominated with Eocene igneous rocks. Volumetrically, andesite units are more abundant. Rose diagrams represent the existence of two main conjugate fault sets with NW/SE and NE/SW trends. The main copper indexes are located in the intersection of volcanic rocks with these two fault sets. Also the results of Fractal analyses reveal the higher Fractal dimension in the Northwestern part of the Shahr-e-Babak area. In the other words the most density of joint and faults occurred in this region.

References:
Carranza, J.M. and Hale, M., 2002. where are porphyry copper deposits spatially localized? A case study in Benguet province, Philippines. Natural Resources Recearch, 11(13): 45-59.
Kesler, S.E., 1997. Metallogenic evolution of convergent margins: Selected ore deposit models. ore Geology Reviews, 12(3): 153-171.
Mehrabi, A., Rangzan, K. and Zarasvandi, A., 2005. Where is significant location for the porphyry copper Deposits? A case study in south centeral Iranian volcanic belt. 9th symposium of Geological Society of Iran, The teacher Training University, Tehran, Iran.
Padilla Garza, R.A., Titley, S.R. and Francisco Pimentel, B., 2001. Geology of the scondida porphyry copper deposit, Antofagosta region, Chile. Economic Geology, 96(2): 307-344.
Vearncombe, J. and Vearncombe, S., 1999. The Spatial Distribution of Mineralization: Applications of Fry Analysis. Economic Geology, 94(4) :475-486.
Zarasvandi, A., 2004. Magmatic and structural controls on localization of the Darreh-Zerreshk and Ali-Abad porphyry copper deposits, Yazd Province, Central Iran. Ph.D. thesis, Shiraz University, Shiraz ,Iran, 280 pp.

1-21

Authors: Mohammad Maanijou; Abbas Nasiri; Farhad Aliani; Mohammad Mostaghimi; Meisam Gholipour; Abbas Maghsoudi

Introduction
The Shahrestanak Mn deposit is located in southern Qom province, 12 km southwest of the city of Kahak. Based on geological-structural divisions of Iran, the deposit belongs to central volcanic belt or Urumieh-Dokhtar zone. The Venarch deposit is one the most important known manganese deposits in Iran. The Sharestanak and Venarch deposits are spatially and temporally related to each other, and have similar geology, mineral texture and structure, host rocks, relationships with faults, and depositional environment. So, their magmatism and deposition conditions can be related to each other. Since no systematic study on the Shahrestanak deposit had been performed before discussing its geological and geochemical characteristics, here it is being attempted to study the geology, petrography, geochemistry of major, minor and trace elements, and Rare Earth Elements (REE) of ore, to distinguish the depositional environments and genesis of this deposit and to compare REE of ore in this deposit with other deposits.

Sampling and method of study
Fourteen samples of manganese ore were selected for geochemical study and analyzing of major, minor, trace elements and REE by ICP-AES and ICP-MS and were sent to SGS Co., Toronto. Detection limits for major elements and trace elements are 0.01% and 0.05ppm, respectively.

Result and discussion
The deposit is characterized by various lithology and stratigraphy units, consist of: 1) Middle to -Upper Eocene volcano-sedimentary rocks, 2) Oligocene lower red conglomerate and sandstone, 3) Oligo-Miocene limestone and marl (Qom Formation), and 4) Eocene and Lower Miocene basic to intermediate dykes. The most abundant minerals of the deposit are braunite, hausmannite, pyrolusite, and manganite. Evidences such as high Mn/Fe (11.33) and Si/Al (4.86) ratios, low contents of trace elements specially Co (11.40 ppm), Ni (24 ppm), Cu (81.85 ppm), and Ce, with high amounts of SiO2, Mn, Fe, Ba, Zn, As and Sr, all represent hydrothermal processes. It seems that hydrogenous processes have not had significant role on the genesis of the Shahrestanak Mn deposit.
During deposition of Fe and Mn from hydrothermal solution, they separated from each other and produced different Fe/Mn ratios in sedimentary exhalative deposit (SEDEX). The Fe/Mn ratios are 5.7 to 40.35 (ave., 11.33). Very high and very low ratios of Fe/Mn can be interpreted as fractionation and separation of these two elements from transportation during hydrothermal activities and mineralization. So, high Fe/Mn ratios here can be considered as in submarine hydrothermal deposits. Cann et al. (Cann et al., 1977) suggested that Fe/Mn ratios in volcano-sedimentary and hydrothermal deposits are so variable and characteristic. Hydrothermal deposits are in close relationships with ferruginous silica gel which itself formed from submarine hydrothermal outpouring and discharging of metals in marine sediments. So, Si wt. % versus Al wt. % is high in exhalative activities. The average Si/Al ratio is 4.86 in the Shahrestanak deposit which is in the range of hydrothermal deposits (SEDEX). Nicholson (Nicholson, 1992) suggested Na versus Mg content diagram for distinction between fresh water, shallow and deep marine environments. Bonatti et al. (Bonatti et al., 1992) introduced Fe-Mn-(Co+Cu+Ni)*10 ternary diagram for distinction between marine sedimentary and hydrothermal Fe-Mn deposit. According to this diagram, hydrothermal oxides depleted in Ni, Cu, Co and zinc relative to sedimentary-marine deposits. Nicholson (Nicholson, 1992) suggested that hydrothermal Mn deposit distinguished with Zn, V, Mo, Cd, Li, Sr, Sb, Pb, Cu, Ba, and As and sedimentary deposit with enrichment in Ni, Cu, Co, Sr, Mg, Ca, Na and K. Hydrogenetic ferromanganese deposit has higher enrichment of Ni, Cu and Co relative to hydrothermal (exhalative) deposit. Low contents of Cu, Co and Ni indicate low input of these elements from hydrothermal activities and derivation of Zn from hydrothermal source. As (Co/Zn)-(Co+Cu+Ni) diagram, the samples from Shahrestanak deposit show close similarities with hydrothermal deposits which in turn show common genesis. Using Pb versus Zn diagram, dubhite (deposits derived from previous mineralized sequence) can be distinguished from other Mn oxide (hydrothermal or supergene) deposits. The dubhite deposits have high Pb/Zn ratios and more than 1 percent Pb and Zn contents. Meanwhile, other types of deposits like shallow marine deposit, hot springs, SEDEX, weathered deposits have lower contents of Pb and Zn. The Shahrestanak deposit has more similarities with SEDEX and shallow marine deposits.

Conclusion
Geological and geochemical evidences show that deposition of ore occurred by submarine hydrothermal activities in Neotethys oceanic basin during Middle to Upper Eocene in calcareous tuff with intercalation of micrite and calcareous limestone. For the genesis of the deposit, it can be stated that the pillow basalt and andesite lavas were leached by hydrothermal activities and Mn, Fe, Si, Ba, Sr and As entered in sedimentary basin by exhalative – volcanic activities through faults, then by regression of the sea and forming oxidizing condition, primary oxide-hydroxide Mn-minerals are deposited.

Acknowledgement
We gratefully thank the Research and Technology Department of Bu-Ali Sina University for supporting the research.

References
Bonatti, E., Kraemer, T. and Rdell, H., 1972. Classification and genesis of submarine iron- manganese deposits of the ocean floor. In: D.R. Horn (Editor), Ferromanganese Deposits of the Ocean Floor. Aren House Harriman, pp. 149-166.
Cann, J.R., Winter, C.K. and Pritchard R.G., 1977. A hydrothermal deposit from the floor of the Gulf of Aden. Mineralogical Magazine, 41(318): 193-199.
Nicholson, K., 1992. Genetic types of manganese oxide deposits in Scotland: Indicators of paleo-ocean-spreading rate and a Devonian geochemical mobility boundary. Economic Geology 87(5): 1301-1309.

39-53

Authors: Abdolnaser Fazlnia; Fariborz Khodadadi; Hosseen Pirkharrati

Introduction
Heavy metals are the most toxic pollutants in aquatic ecosystems. This contamination can result from the release of heavy metal elements during alteration and weathering of ultramafic and mafic rocks (ophiolite zones). Among the important metals and pollutants in the ophiolite; chromium, cobalt, nickel, iron, magnesium, manganese, zinc and copper could be noted. Basically, a mass of serpentine consists of serpentine, amphibole, talc, chlorite, magnetite, and the remainder of olivine, pyroxene and spinel (Kil et al., 2010). In such areas, the prevailing cold climate, during the serpentinization, chloritization and epidotiization, the activity of the solvent, such as chloride, fluoride, carbonates, sulfide, sulfosalt would be able to import the elements such as magnesium and iron, copper and zinc into the soil and groundwater. The study area is located in northwestern Iran. This area is located in the northwest of the city of Khoy.
Because of the proximity to the north and northwest Khoy plains with ophiolite rocks, the soil of this region could possibly show the potential of contamination with heavy metals. Due to the toxicity and disease of unauthorized grades of these elements in groundwater in the study area, this study is focused on the more contaminated groundwater of the areas.

Materials and methods
In this study, over a period of 5 days, sampling from 42 water sources, including fountains, aqueducts, wells, piezometers and wells in operation, was performed. The container was washed with acid and then rinsed 3 times with the water sample. The pH and temperature of the water in the samples was measured in the field. Then to each of the samples was taken from 2 to 5 ml of concentrated nitric acid (This causes that the metal elements would not adsorbed or precipitated by these particles) and pH of the samples was measured with litmus paper to reach level 2. This was done to ensure the consolidation of the water samples. Analysis of samples carried out in the chemistry laboratory of the University of Urmia. All water sampling procedures were performed based on standard protocols (SMEWW, 2010). The maximum concentration of heavy metal contamination of drinking water with EPA, WHO and national standards were compared. In this study, the chemical analysis of heavy metals, were used by graphite furnace atomic absorption spectrometry (at ppb) for the elements Cu, Mg, Fe and Zn. Concentration of the heavy metals in acidified water samples (pH value of 2), using a flame atomic absorption spectrophotometer were analyzed.

Discussion
There are enormous amounts of Fe and magnesium in groundwater from the north and northwest Khoy plain, and the amount of Cu and zinc are in the normal range in water resources. The source of iron and magnesium in the groundwater of the study area is ultramafic and mafic rocks of the Khoy ophiolite complex. Weathering of ultramafic and mafic igneous rocks such as peridotite, olivine basalt, gabbro and pillow lava and then soil formation, high concentrations of the elements Mg and Fe were transferred to soil. Ferromagnesian olivine is formed Mg2+ and Fe2+ ions and tetrahedral silicon. If sufficient amount of Mg2+ and Fe3+ ions combine with silicon and oxygen, silicon into the soil, forms silicic acid (H4SiO4), or magnesium or iron smectite (clay minerals) (Alexander et al., 2007). Several types of pyroxene are more stable than olivine. Orthopyroxene during weathering decompose into talc and smectite. Magnesite (MgCO3) is present in some serpentine soils.
With respect to the empirical relationship (Kierczak et al., 2007) and based on temperature and rainfall, the study area with a drought index of 12.48 places in the category of semi-arid-cold climate between 10 and 19.9. Temperature changes in the condition cause weathering and leaching of serpentine soils, and subsequently can remove large amounts of magnesium. Weathering and leaching serpentine soils, releases immediately magnesium and its concentration in soil decreases. As a result, the concentration of the element in the water increases.

Results
Based on the charts and maps of iron, magnesium, zinc and copper contaminations, it is found that the concentrations of Fe and Mg in the north and northwest Khoy plain are higher than the permissible limit for drinking water. In some parts of the sample, the concentrations of Cu and Zn are exceeded WHO. However, based on EPA standard, the amount of copper is less than the limit. On the basis of three criteria: EPA, WHO and national standards, except for the village Ghez Ghaleh, zinc concentration is below the standard. According to the geological map of Khoy, the Khoy ophiolite complex containing mafic rocks and ultramafic is a source of iron and magnesium in groundwater.

Acknowledgements
Editor of the Journal of Economic Geology, Professor Mohammad Hassan Karimpour and reviewers of this article are acknowledged for their unwavering assistance. Also, the authors thank Deputy of Research of the University of Urmia for the support required for this study.

References
Alexander, E.B., Coleman, R.G., Keeler-Wolf, T. and Harrison, S., 2007. Serpentine Geoecology of Western North America, Geology, Soils, and Vegetation. Oxford University Press, London, United Kingdom, 512 pp.
Kierczak, J., Neel, C., Bril, H. and Puziewicz, J., 2007. Effect of mineralogy and pedoclimatic variations on Ni and Cr distribution in serpentine soils under temperate climate. Geoderma, 142(2): 165–177.
Kil, Y., Lee, S.H., Park, M.H. and Wendlandt, R.F., 2010. Nature of serpentinization of ultramafic rocks from Hero Fracture Zone, Antarctic: Constraints from stable isotopes. Marine Geology, 274(1): 43–49.
SMEWW, 2010. Standard Methods for the Examination of Water and Wastewater (SMEWW). American Public Health Association (20th Edition), New York, 2671 pp.

69-90

Authors: Alireza Almasi; Mohammad Hassan Karimpour; Khosrow Ebrahimi Nasrabadi; Behnam Rahimi; Urs KlÖTzli; Jose Francisco Santos

Introduction
The study area is located in central part of the Khaf- Kashmar-Bardeskan belt which is volcano-plutonic belt at the north of the Dorouneh fault in the north of Lut block. The north of the Lut block is affected by tectonic rotation and subduction processes which occur in the east of Iran (Tirrul et al., 1983). The magmatism of Lut block begins in Jurassic and continues in Tertiary (Aghanabati, 1995). Karimpour (Karimpour, 2006) pointed out the Khaf-Kashmar-Bardeskan belt has significant potential for IOCG type mineralization such as Kuh-e-Zar, Tannurjeh, and Sangan (Karimpour, 2006; Mazloumi, 2009). The data gathered on the I-type intrusive rocks include their field geology, petrography, U–Pb zircon dating and Sr–Nd isotope and also alteration and mineralization in the study area.

Materials and methods
- Preparation of 150 thin sections of rock samples for study of petrography and alteration of the intrusive rocks.
- Magnetic susceptibility measuring of intrusive rocks.
- U-Pb dating in zircon of I-type intrusive rocks by Laser-Ablation Multi Collector ICP-MS method. - Sr-Nd analysis on 5 samples of I-type intrusive rocks by Multi-Collector Thermal Ionization Mass Spectrometer (TIMS) VG Sector 54 instrument. - Mineralography and paragenetic studies of ore-bearing quartz veins and geochemical analysis for 28 samples.
- Production of the geology, alteration and mineralization maps by scale: 1:20000 in GIS.

Results
Oblique subduction in southern America initiated an arc-parallel fault and shear zones in the back of continental magmatic arc (Sillitoe, 2003). Because of this event, pull-apart basins were formed and high-K to shoshonitic calc-alkalineI- and A-type magmatism occur (Sillitoe, 2003). Most important deposits accompany with this magmatism are Au-Cu deposits types and Fe-Skarns (Sillitoe, 2003). We have similar scenario to Neotethys subduction. Khaf-Kashmar-Bardeskan volcano-plutonic belt is located between Neotethys suture and Alborz- Sabzevar Back- arc (Asiabanha and Foden, 2012). We suggest Khaf-Kashmar-Bardeskan volcano-plutonic belt forms at the arc-parallel fault and shear zones in the back of continental magmatic arc. In the basis of all evidences (Shear zone system, high-K to shoshonitic calc-alkaline I- and A-type magmatism, typical alterations related to upper zones of IOCG deposits and IOCG mineralization), we suggest IOCG (Au-Cu) mineralization in Kashmar.

Discussion
On the basis of former regional (Muller and Walter, 1983) and local structural studies (this research), regional compression causes sinistral strike-slip movements of Dorouneh and Taknar faults, shear zone, pull-apart and Riedel fractures (P, R and R' types) in the study area. These events cause magma intrusion and circulation of hydrothermal fluids. On the basis of geology, geochemistry and magnetic susceptibility measuring of intrusive rocks, several high K to shoshonitic calc-alkaline to alkaline I-type and one A-type intrusive rocks are intruded in Kashmar area. Swarm dykes are the youngest and the agent for alteration and mineralization. U-Pb dating related to quartz monzonite body (preventative sample for I-type intrusive rocks which are older than A-type series) show 40 Ma (Middle Eocene) for this rock group in Kashmar. The mean of initial 87Sr/86Sr and 143Nd/144Nd are 0.705-0.707 and 0.5135-0.5126 for I-type series, respectively. εNd(i) amounts for I-type series are in negative to positive limit ranges (-1.65 to 1.33). These amounts show subduction source with contamination to continental crust.
Two type alteration and mineralization occur in Kashmar: 1) primary alterations (advanced argillic+ sericite+ silicification) which are synchronous with sulfide base-metal veins (chalcopyrite+ pyrite± galena± quartz± chloride) and 2) Lateral alterations (carbonatization+ Fe-oxides+ silicification+ epidotization+ chloride+ sericite+ barite) which are synchronous with IOCG veins (specularite+ chalcopyrite+ pyrite± galena± sphalerite± barite± siderite ± etc.). Primary centralized and sulfide base-metal veins in crosscutting points between Dorouneh fault and minor faults. Bahariyeh, Uchpalang and Sarsefidal areas are located in these crosscutting points. Tourmaline (demorterite) ±chloride fill the fractures in the intrusive rocks of southern part of area next to the Dorouneh fault occasionally. Lateral alteration synchronous with IOCG veins occur in Kamarmard area. Geochemical data of all veins show Cu, Pb, Zn anomalies (>1%) in two type veins, Au anomalies (to about 15 ppm) only in IOCG veins, Mn anomalies in two type veins and Ba anomalies in IOCG veins.
Alteration and mineralization in the world-class IOCG deposits identified by sodic-calcic and potassic (hydrothermal actinolite and biotite) and magnetite± gold in deep parts (Sillitoe, 2003) and advanced argillic+ pyrite+ sericite+ toulrmaline (demorterite) in shallow parts (Ray and Dick, 2002). Generally, alteration in the study area is similar to shallow parts of world-class IOCG deposits. Tanourjeh is a IOCG deposit next to the northwest of the study area. In Tanourjeh, the gold-bearing magnetite is synchronous to potassic alteration (hydrothermal biotite) and other alterations are advanced argillic, silicification and sericite. These characteristics are similar to deep parts of world-class IOCG deposits. Bahariyeh, Uchpalang and Sarsefidal have similarities to alterations in Tanourjeh. Considering Tanourjeh lie in the lower level rather to Bahariyeh, Uchpalang and Sarsefidal, we believe they erosion surface in Tanourjeh is lower. Kamarmard lies in the highest erosion surface in the study area. Alterations and Mineralization as similar to Kuh e Zar IOCG deposit (specularite+chalcopyrite+gold) which is next to the Kamarmard area in Northeast of study area. In Bahariyeh-Uchpalang areas we can see only one IOCG vein but in Sarsefidal area exist several IOCG vein. Because of current surface in Bahariyeh-Uchpalang areas is lower than Sarsefidal current surface in Sarsefidal is lower than Kamarmard, we believe that IOCG vein in Bahariyeh-Uchpalang area have been eroded. We Believe to two circulation of oxidized Fe-bearing hydrothermal fluid in Kashmar. During the first circulation, Potassic alteration and gold-bearing magnetite bodies in depth and primary alterations with sulfide base-metal veins was formed. At the second circulation, lateral alterations and IOCG veins was formed at the near of paleo-surface.

References
Aghanabati, A., 1995. Geology of Iran. Geological Survey of Iran, Iran, 606 pp.
Asiabanha, A. and Foden, J., 2012. Post-collisional transition from an extensional volcano-sedimentary basin to a continental arc in the Alborz Ranges, N-Iran. Lithos, 148: 98-111.
Karimpour, M.H., 2006. Cu-Au mineralizaion accompany with magnetite-specularite (IOCG) and examples in Iran. 9th Geological Society of Iran Conference, Tarbiat Moallem University, Tehran, Iran.
Mazloomi Bajestani, A., 2009. Mineralization, Geochemistry and Au-W mineralization in Koh e Zar of Torbat e Heydarieh area. Ph.D. Thesis, University of Shahid Beheshti, Tehran, Iran, 291 pp.
Muller, R. and Walter, R., 1983. Geology of the Precambrian-Paleozoic Taknar inlier, northwest of Kashmar, Khorasan province, northeast Iran. Geological Survey of Iran, Tehran, Report 50, 252 pp.
Ray, G.E. and Dick, L.A., 2002. The Productora prospect in north-central Chile: An example of an intrusion-related Candelaria type Fe-Cu-Au hydrothermal system. Porter GeoConsultancy Publishing, Adelaide, 2:131–151.
Sillitoe, R.M., 2003. Iron oxide-copper-gold deposits: An Andean view. Mineralium Deposita, 38(7): 787–812.
Tirrul, R., Bell, I.R., Griffis, R.J. and Camp, V.E., 1983. The Sistan suture zone of eastern Iran. Geological Society of America Bulletin, 94(1): 134-150.

111-127

Authors: Mohammad Ebrahimi; Hossein Kouhestani; Ehsan Shahidi

Introduction
Mesgar iron occurrence is located in northwestern part of the Central Iran, 115 km south of Zanjan. Although there is a sequence of volcanic-pyroclastic rocks accompanied by iron mineralization, no detailed works had been conducted in the area. The present paper provides an overview of the geological framework, the mineralization characteristics, and the results of geochemical study of the Mesgar iron occurrence with an application to the ore genesis. Identification of these characteristics can be used as a model for exploration of this type of iron mineralization in the Central Iran and elsewhere.

Materials and methods
Detailed field work has been carried out at different scales in the Mesgar area. About 16 polished thin and thin sections from host rocks and mineralized and altered zones were studied by conventional petrographic and mineralogic methods at the Department of Geology, University of Zanjan. In addition, a total of 3 samples from least-altered volcanic host rocks and 2 samples from ore zones from the Mesgar occurrence were analyzed by ICP-MS and ICP-OES for whole-rock major and trace elements and REE compositions at the Zarazma Laboratories, Tehran, Iran.

Results and Discussion
Based on field observation, rock units exposed in the Mesgar area consist of Miocene sedimentary rocks and volcanic-pyroclastic units (Rādfar et al., 2005). The pyroclastic units consist of volcanic breccia and agglomerate. They lie concordantly on the Miocene sedimentary units, and are in turn concordantly overlain by andesitic basalt lavas. The lavas show porphyritic texture consisting of plagioclase (up to 3 mm in size) and pyroxene phenocrysts set in a fine-grained to glassy groundmass. Seriate, cumulophyric, glomeroporphyritic and trachytic textures are also observed.
Iron mineralization occurs as vein and lens-shaped bodies within and along the contacts of pyroclastic (footwall) and andesitic basalt lavas (hanging wall). The veins reach up to 150 m in length and average 1.5 m in width, reaching a maximum of 3 m. Two stages of mineralization identified at Mesgar. Stage-1 mineralization formed before the hydrothermal brecciation events. This stage is characterized by disseminated fine-grained hematite in the andesitic basalt lavas. Clasts of stage-1 mineralization have been recognized in the hydrothermal breccias of stage-2. Stage-2 is represented by quartz, hematite and chlorite veins and breccias cement. This stage contains abundant hematite, together with minor magnetite and chalcopyrite.
The hydrothermal alteration assemblages at Mesgar grade from proximal quartz and chlorite to distal sericite and chlorite-calcite. The quartz and chlorite alteration types are spatially and temporally closely associated with iron mineralization. The sericite and chlorite-calcite alterations mark the outer limit of the hydrothermal system. Supergene alteration (kaolinite) is commonly focused along joints and fractures.
The ore minerals at Mesgar formed as vein and hydrothermal breccia cements, and show vein-veinlet, massive, brecciated, clastic and disseminated textures. Hematite is the main ore which is accompanied by minor magnetite and chalcopyrite. Goethite is a supergene mineral. Quartz and chlorite are present in the gangue minerals that represent vein-veinlet, vug infill, colloform, cockade and crustiform textures.
The Mesgar volcanic host rocks are characterized by LILE and LREE enrichment coupled with HFSE depletion. They have positive U, Th and Pb and negative Ba, Nb, P and Ti anomalies. Our geochemical data indicate a calc-alkaline affinity for the volcanic rocks (Kuster and Harms, 1998; Ulmer, 2001), and suggest that they originated from mantle melts contaminated by the crustal materials (Chappell and White, 1974; Miyashiro, 1977; Harris et al., 1986). The ore zones show lower concentrations of REE, except Ce, relative to fresh volcanic host rocks. LREE are more depleted than HREE. These signatures indicate high rock-fluid interaction in Mesgar.
Comparison of the geological, mineralogical, geochemical, textural and structural characteristics of the Mesgar occurrence with different types of iron deposits reveals that iron mineralization at Mesgar is originally formed as volcano-sedimentary, and then reconcentrated as vein mineralization by hydrothermal fluids (Barker, 1995; Marschik and Fontbote, 2001, Shahidi et al., 2012).

Acknowledgements
The authors are grateful to the University of Zanjan Grant Commission for research funding. Journal of Economic Geology reviewers and editor are also thanked for their constructive suggestions on alterations to the manuscript.

References
Barker, D.S., 1995. Crystallization and alteration of quartz monzonite, Iron Spring mining district, Utah, relation to associated iron deposits. Economic Geology, 90 (8): 2197–2217.
Chappell, B.W. and White, A.J.R., 1974. Two contrasting granite types. Pacific Geology, 8(2): 173–174.
Harris, N.B.W., Pearce, J.A. and Tindle, A.G., 1986. Geochemical characteristics of collision-zone magmatism. In: M.P. Coward, and A.C. Ries (Editors), Collision Tectonics. Geological Society of London, Special Publication, pp. 67–81.
Kuster, D. and Harms, U., 1998. Post-collisional potassic granitoids from the southern and northern parts of the Late Neoproterozoic East Africa Orogen: a review. Lithos, 45(1): 177–195.
Marschik, R. and Fontbote, L., 2001. The Candelaria-Punta Del Cobre iron oxide Cu-Au (-Zn-Ag) deposits, Chile. Economic Geology, 96(8): 1799–1826.
Miyashiro, A., 1977. Nature of alkalic volcanic series. Contributions to Mineralogy and Petrology, 66(1): 91–110.
Rādfar, J., Mohammadiha, K. and Ghahraeipour, M., 2005. Geological map of Zarrin Rood (Garmab), scale 1:100,000. Geological Survey of Iran.
Shahidi, E., Ebrahimi, M. and Kouhestani, H., 2012. Structure, texture and mineralography of Mesgar iron occurrence, south Gheydar. 4th Symposium of Iranian Society of Economic Geology, University of Birjand, Birjand, Iran. (in Persian with English abstract)
Ulmer, P., 2001. Partial melting in the mantle wedge- the role of H2O in the genesis of mantle-derived arc-related magmas. Physics of the Earth and Planetary Interiors, 127(1): 215–232.

147-163

Authors: Farid Moore; Abbas Etemadi; Sina Asadi; Nasim Fattahi

Introduction
One of the first principles in the formation of a reserve is mineralogical, construction and mineral textures studies and investigation of paragenetic relations in the ore minerals. In addition, to petrographic studies, isotopic investigates have wide applications in economic geology. In general, copper isotope variability in primary (high temperature) mineralization forms a tight cluster, in contrast to secondary mineralization, which has a much larger isotope range. A distinct pattern of heavier copper isotope signatures is evident in supergene samples, and a lighter signature characterizes the leached cap and oxidation-zone minerals. This relationship has been used to understand oxidation–reduction processes (Hoefs, 2009). Also for a better understanding of the origin of the Jian Cu deposit, this research focuses on the origin and composition of the fluid and elucidation of its evolution during the mineralization process. In order to achieve this end, field observations, vein petrography, microthermometry of fluid inclusions and stable isotope analyses of veins and minerals were investigated. The present study also compares high and low temperature sulfide samples in an attempt to document and explain diagnostic δ65Cu ranges in minerals from the Jian deposit.

Materials and methods
The samples were taken from different depths to measure Cu isotope variations within each reservoir. Mineralogical composition was determined using X-ray diffractometry. In addition, chromatographic separation was carried out on all samples (except for native Cu samples) in a clean lab and was conducted as outlined in Mathur et al. (Mathur et al., 2009). These samples were measured into a Multicollector Inductively-Coupled-Plasma Mass Spectrometer (MC-ICPMS, the Micro mass Isoprobe at the University of Arizona) in low resolution mode using a microconcentric nebulizer to increase sensitivity for the samples with lower concentrations of copper. Preparation and analysis of quartz for oxygen isotopes was performed using the standard techniques detailed by Clayton and Mayeda (Clayton and Mayeda, 1963). Fluid inclusions were extracted for δD measurement from quartz samples selected as far as possible to avoid late inclusions. The methods were standard and similar to those published in Fallick et al. (Fallick et al., 1987). Stable isotope analysis for oxygen and hydrogen isotopes was undertaken at the isotope geochemistry laboratory, University of Queensland.

Results
δ65Cu values for analyzed samples range from -0.45 to +0.49 ‰ in the secondary copper minerals (malachite). The δ18O values for analyzed quartz samples, collected from different quartz veins of the Jian deposit, fall in a narrow range varying from +15.8 to +18.4‰ (avg. +16.7‰) for type A veins and +16.6 to +17.9‰ (avg. +17.2‰) for type B veins. The δ18O values of the fluids calculated from the Jian quartz samples range from +7.6 to +10.7‰ (avg. +9.1 ‰) for type A veins and +4.7 to +5.1‰ (avg. +4.9 ‰) for type B veins. The δD values of the fluid inclusions hosted by quartz samples range from -33.1 to -41.2‰ (avg. -37.6‰) for type A and -52.3 to -54.9‰ (avg. -53.1‰) for type B veins.

Discussion
Based on mineralization style and structures, Th, salinity and composition of fluid inclusions, stable isotope systematics, timing of the mineralization with respect to deformation and metamorphism, host rocks, ore and gangue minerals, the Jian deposit can be classified either as a metamorphogenic or mesothermal Cu-bearing quartz deposit. Precipitation of secondary Cu+-sulfide minerals from the Cu+ complexes present in this fluid would result in sulfide minerals with low copper isotopic variations (-0.45 to +0.49‰) in the Jian copper deposit. This could explain why a low variation in the isotopic composition of Cu is observed in a horizontal plane. Isotopically, mineralization is most probably the result of varied isotopic fractionation processes including low copper leaching, Cu+ to Cu2+ oxidation-reduction reactions, and fluid-mineral fractionations. Oxygen and hydrogen isotope compositions suggest that the main metallization occurred from a metamorphic dehydration in type A veins. These sulfide-bearing quartz veins are interpreted as a small-scale example of redistribution of mineral deposits by metamorphic fluids. This study suggests that mineralization at Jian is interpreted as metamorphogenic in style, probably related to a deep-seated mesothermal system.

Acknowledgements
The authors would like to thank Managing director of the Jian Corporation Ltd. for his help during fieldwork and sampling. Logistical and financial supports were provided by Department of Earth Sciences, Faculty of Sciences, Shiraz University.

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