Journal of African Earth Sciences 107 (2015) 1–14

Contents lists available at ScienceDirect

Journal of African Earth Sciences

journal homepage: www.elsevier .com/locate / ja f rearsc i

Mineralogic, fluid inclusion, and sulfur isotope evidence for the genesisof Sechangi lead–zinc (–copper) deposit, Eastern Iran

http://dx.doi.org/10.1016/j.jafrearsci.2015.03.0151464-343X/� 2015 Elsevier Ltd. All rights reserved.

⇑ Corresponding author. Tel./fax: +98 (511) 8797275.E-mail addresses: shafaroudi@um.ac.ir (A. Malekzadeh Shafaroudi), karimpur@

um.ac.ir (M.H. Karimpour).1 Tel./fax: +98 (511) 8797275.

Azadeh Malekzadeh Shafaroudi ⇑, Mohammad Hassan Karimpour 1

Research Center for Ore Deposit of Eastern Iran, Ferdowsi University of Mashhad, P.O. Box 91775-1436, Mashhad, Iran

a r t i c l e i n f o

Article history:Received 15 December 2013Received in revised form 14 March 2015Accepted 19 March 2015Available online 27 March 2015

Keywords:Pb–Zn–Cu mineralizationEpithermal depositFluid inclusionSulfur isotope: Lut blockIran

a b s t r a c t

The Sechangi lead–zinc (–copper) deposit lies in the Lut block metallogenic province of Eastern Iran. Thisdeposit consists of ore-bearing vein emplaced along fault zone and hosted by Late Eocene monzoniteporphyry. Hydrothermal alteration minerals developed in the wall rock include quartz, kaolinite, illite,and calcite. Microscopic studies reveal that the vein contains galena and sphalerite with minor chalcopy-rite and pyrite as hypogene minerals and cerussite, anglesite, covellite, malachite, hematite, and goethiteas secondary minerals. Fluorite and quartz are the dominant gangue minerals and show a close relation-ship with sulfide mineralization. Calculated d34S values for the ore fluid vary between �9.9‰ and �5.9‰.Sulfur isotopic compositions suggest that the ore-forming aqueous solutions were derived from mag-matic source and mixed with isotopically light sulfur, probably leached from the volcanic and plutoniccountry rocks. Microthermometric study of fluid inclusions indicates homogenization temperatures of151–352 �C. Salinities of ore-forming fluids ranged from 0.2 to 16.5 wt.% NaCl equivalent. The ore-forming fluids of the Sechangi deposit are medium- to low-temperature and salinity. Fluid mixing mayhave played an important role during Pb–Zn (–Cu) mineralization. The key factors allowing for metaltransport and precipitation during ore formation include the sourcing of magmatic fluids with highcontents of metallogenic elements and the mixing of these hydrothermal fluids with meteoric watersresulting in the formation of deposit. In terms of the genetic type of deposit, the Sechangi is classifiedas a volcanic–subvolcanic hydrothermal-related vein deposit.

� 2015 Elsevier Ltd. All rights reserved.

1. Introduction

Cenozoic magmatic rocks in Iran are distributed mostly in fourbelts (Fig. 1A). The Urumieh-Dokhtar magmatic arc extends forover 1700 km in the NW–SE direction, which includes world-classporphyry copper deposits such as Sarcheshmeh and Miduk(Waterman and Hamilton, 1975; Forster, 1978; Berberian et al.,1982; Mohajjel et al., 2003; Shahabpour, 2005, 2007; Ghasemiand Talbot, 2006; Shafiei et al., 2009; Boomeri et al., 2009). TheAlborz-Azarbaijan magmatic belt, in the north, extends for800 km, varying between NW–SE and W–E directions (Nabavi,1976); the western end of this belt merges into the Urumieh-Dokhtar belt (Fig. 1A). The west of the belt, known as Arasbaranmetallogenic zone, hosts the world-class Sungun porphyry Cu–Mo deposit (Calagari et al., 2001; Calagari, 2003), Anjerd, Sungun,and Mazraeh Cu skarn deposits (Karimzadeh Somarin and

Hosseinzadeh, 2002; Karimzadeh Somarin, 2004), and severalepithermal style gold occurrences. Hassanzadeh et al. (2002)presented evidence for an intra-arc rifting in Urumieh-Dokhtarmagmatic belt during Oligocene–Miocene, leading to the sep-aration and northward movement of what is now known asAlborz-Azarbaijan magmatic belt (Fig. 1A). The Khaf-Kashmar-Bardaskan magmatic belt crosses NE Iran (Fig. 1A), which has sig-nificant potential for iron oxide type mineralization, includingiron-oxide copper–gold (IOCG) and magnetite deposits, such asKuh-e-Zar, Shahrak, Tannurjeh, and Sangan (Karimpour, 2004;Mazloumi et al., 2009; Yousefi et al., 2009). The east-trending,�50 km wide belt extends �400 km along the north side of theDuroneh Fault (Malekzadeh Shafaroudi et al., 2013a). The EasternIran belt extends for 1000 km in the N–S direction, within theLut block (Fig. 1A). This block is bounded to the east by theNehbandan and associated faults, to the north by the Dorunehand related faults (Sabzevar zone), and to the west by theNayband Fault (Fig. 1A and B). The Lut block is the main metallo-genic province in east of Iran (Karimpour et al., 2012) that com-prises numerous porphyry Cu and Cu–Au deposits, low and highsulfidation epithermal Au deposits, and Cu–Pb–Zn vein-type

Fig. 1. A. A simplified map showing the main geological divisions, and the distribution of the Cenozoic magmatic assemblages, in Iran (after Stocklin, 1968; Alavi, 1996). B.Tertiary igneous rocks of the Lut block, Eastern Iran, showing the locations of Sechangi and some base metal vein-type deposits. Based on maps from the Geological Survey ofIran (1989, 2009, and various 1:250,000-series maps).

2 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

deposits (Malekzadeh Shafaroudi, 2009; Arjmandzadeh et al.,2011; Karimpour et al., 2012; Richards et al., 2012; MalekzadehShafaroudi and Karimpour, 2013a). Karimpour et al. (2012) studiedthe relationship of Rb–Sr isotope, geochemistry, and age data of

Tertiary granitoid rocks (syn-mineralization units) with differenttypes of mineralization in the Lut block. They concluded that theage of these intrusions is between middle Eocene to lowerOligocene (43.3–33.3 Ma.). In addition, the initial 87Sr/86Sr ratios

A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14 3

vary from 0.7051 to 0.7047, which indicate that these magmasoriginated from oceanic crust. Therefore, the period during whichthe formation of the ore minerals took place coincides withMiddle Eocene to Lower Oligocene. This period, which is referredto as the metallogenic epoch for the Lut block also correspondsto the subsequent phase of the Pyrenean episode of the MiddleAlpine orogeny (Karimpour et al., 2012).

The Sechangi Pb–Zn (–Cu) deposit is situated approximately123 km southwest of the town of Birjand, South Khorasan province,in Eastern Iran (Fig. 1B). This deposit is one of the many igneousbasement-hosted hydrothermal base-metal vein deposits in theLut block mineral district (Fig. 1B). The mining history of theSechangi deposit goes back to ancient time when the mine probablysupplied the first known lead products in the area. It was reopenedin 1963 but insufficient development work (drill core was notdrilled) and late 1975 saw its closure. Many vertical shafts existin the area that they are unavailable due to collapse damage.Azimi and Saeedi (1975) reported a daily production of 30 tons,averaging 6% Pb and 3% Zn. Underground work has followed theore to a depth of 140 m, where the zinc/lead ratio increases (up to3). The zinc/lead ratio is less than 1 at shallower levels.

Mineralization in the Sechangi deposit was described in generalby Bazin and Hubner (1969) and Tarkian et al. (1984), but they didnot study mineral paragenesis, fluid evolution and ore genesis. Inthis paper, therefore, we carried out first geological investigations,including field geology, ore microscopy, fluid inclusion microther-mometry, and sulfur isotope geochemistry, which help to clarifythe ore genesis of the Sechangi Pb–Zn (–Cu) deposit.

2. Geological background

Tectonically, the Sechangi Pb–Zn (–Cu) deposit is located in thewest of Lut block near the Nayband fault (Fig. 1B) and hosted byTertiary igneous rocks. This block is one of the several micro-continental blocks interpreted to have rifted from the northernmargin of Gondwana during the Permian opening of the Neo-Tethys Ocean, which was subsequently accreted to the Eurasiancontinent in the Late Triassic during the closing of the Paleo-Tethys Ocean (Golonka, 2004). Previous studies on the tectonicand magmatic evolution of the Lut block yielded contradictoryresults of plate tectonic models. Along the eastern margin of theblock, the arcuate branches of the bordering N–S fault systemextend into the interior of the block. Berberian (1973) suggestedthat the Lut block behaved rigidly and it has been argued thatthe block underwent a large anticlockwise rotation in responseto the collision between India and Eurasia (Westphal et al., 1986;Besse et al., 1998; Bagheri, 2008).

The present eastern border of the Lut block would havebelonged to the active margin of the subducted Neotethys Ocean(Dercourt et al., 1986; Golonka, 2004; Bagheri and Stampfli,2008). This ocean closed in Eastern Iran, between the Afghan andLut plates, in Oligocene Middle Miocene (Sengör and Natalin,1996). The Eastern Iran ophiolite complex marks the boundarybetween the Lut and Afghan continental blocks. Some authorsdenied the influence of a subduction zone and attributed themineralization in the Lut block to an extensional geotectonic zone(Jung et al., 1983; Samani and Ashtari, 1992). However, Saccaniet al. (2010) studied the ophiolitic complex of Eastern Iran,between the Lut and the Afghan continental blocks, and consideredthat the subduction of oceanic lithosphere played a major role andthat it should have taken place beneath the Afghan block. On theother hand, Eftekharnejad (1981) proposed that magmatism inthe northern Lut area resulted from subduction beneath the Lutblock. Additionally, Berberian (1983) showed that igneous rocksof this block have calc-alkaline signatures. The accretionary

prism-forearc basin polarity, the structural vergence, and youngl-ing of the accretionary prism to the southwest are consistent witha north-east-dipping subduction (Tirrul et al., 1983). Recently,asymmetric subduction models have been discussed for situationssimilar to that of the Lut block (Doglioni et al., 2009;Arjmandzadeh et al., 2011).

The Lut block extends some 900 km from the Doruneh fault inthe north to the Juz-Morian basin in the south, but is only�200 km wide (Stocklin and Nabavi, 1973; Dehghani, 1981). TheLut block is consist of pre-Jurassic metamorphic basement,Jurassic sediments and several generations of Late Mesozoic andCenozoic intrusive and/or volcanic rocks (Camp and Griffis, 1982;Tirrul et al., 1983). Radiometric age data indicate that the oldestmagmatic activity in the central Lut block took place in theJurassic (Tarkian et al., 1984). Rb–Sr isotope determinations, basedon whole-rock and biotites from the Sorkh Kuh granitoid yieldMiddle to Late Jurassic ages (164.8 ± 1.9 Ma and 170 ± 1.9 Ma,respectively). Intrusive igneous activity of a similar age is alsorecognized in the Deh-Salm metamorphic complex in the easternLut block (Mahmoudi et al., 2010). Further to the north, magmaticactivity started in the Upper Cretaceous time (75 Ma) and gener-ated both volcanic and intrusive rocks (Tarkian et al., 1984). TheMiddle Eocene (47 Ma) was characterized by alkaline and shosho-nitic volcanism (Tarkian et al., 1984). Volcanic activity peak is atthe end of the Eocene. In addition, calc-alkaline series basalts andbasaltic andesite erupted in the Eocene–Oligocene (40–31 Ma).

The geology of the Sechangi district is dominated by volcanicrocks of Eocene age, which cover an area of about 50 km2 and com-prise biotite–pyroxene latite and biotite–pyroxene trachyandesite(Fig. 2). These porphyritic rocks composed mainly of plagioclase(andesine–oligoclase), alkali feldspar, quartz, biotite, pyroxene(augite–diopside), magnetite, and zircon. Subvolcanic intrusionsoccur in the Sechangi area, the largest of which is the biotite–pyrox-ene monzonite porphyry stock, which occurs in the north to north-east of the district where it intrudes the volcanic rocks(Figs. 2 and 3A). The Pb–Zn (–Cu) vein mineralization is hosted bybiotite–pyroxene monzonite porphyry and this unit is altered byore-fluid in the vicinity of vein (Figs. 2 and 3B). Geochronologicalstudy by Kluyver et al. (1978) gave a K/Ar age of 37.5 ± 2 Ma (LateEocene) for the rock. The biotite–pyroxene monzonite porphyryhas porphyritic (0.4–5 mm) and glomeroporphyritic textures withmedium-grained groundmass. The modal amount of phenocrystsis up to 35–40 vol.% in total, including 16–18 vol.% plagioclase(andesine–oligoclase), 14–16 vol.% K-feldspar, 3–4 vol.% clinopy-roxene (augite–diopside), and 1–2 vol.% biotite. The same mineralsare also present in the groundmass. Accessory minerals are mag-netite, zircon and apatite. Common secondary minerals in the vicin-ity of vein are quartz, calcite, kaolinite and illite. This rock ischaracterized by 61–64 wt.% SiO2, 14–15 wt.% Al2O3, 4.5–6 wt.%K2O, 1.7–1.9 K2O/Na2O ratio, enrichment in large ion lithophile ele-ments (LILE) and LREE, low high field strength elements (HFSE) andHREE depletion ((La/Yb)N = 9–16.5). This has features typical ofhigh–K calc-alkaline rock and is metaluminous formed in a volcanicarc setting. The magma exhibit low degree of partial melting (>0.1to <3) from a garnet-spinle lherzolite source, which is contaminatedby continental crust (Malekzadeh Shafaroudi et al., 2013b).

The biotite syenite porphyry is other subvolcanic intrusion inthe area, which is exposed in the northwest of the map(Figs. 2 and 3C), extensively altered to argillic–silicification alter-ation zones. This rock has a porphyritic texture (0.2–4 mm) withmedium-grained groundmass. The rock consists of 5–6 vol.% pla-gioclase, 15–20 vol.% K-feldspar, and 1–2 vol.% biotite as phe-nocrysts. The same minerals are also present in the groundmass.Accessory minerals include magnetite and zircon. Quartz, kaolinite,and illite are the main secondary minerals. Feldspar phenocrysts,especially plagioclase, have been altered to clay minerals.

Fig. 2. Geologic-alteration map of the Sechangi deposit.

Fig. 3. A. Typical outcrop of light gray to green biotite–pyroxene monzonite porphyry. B. Vertical shaft on Pb–Zn (–Cu) vein hosted by biotite–pyroxene monzonite porphyry.C. Typical outcrop of biotite syenite porphyry in the northeastern Seghangi deposit.

4 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14 5

3. Hydrothermal alteration

Much of the host rock to the vein mineralization has sufferedthe effects of hydrothermal alteration and most of the metaso-matic changes are clearly associated with the mineral vein.This wall rock alteration is not consistently developed, but threedistinct assemblages have been recognized: silicification (quartzvein), argillic, and carbonatization (calcite vein). Alteration stylesdirectly related to Pb–Zn (–Cu) mineralization are fluoritizationand silicification associated with minor argillic and carbonatiza-tion (Fig. 2). These various alteration styles are briefly describedbelow.

(1) Silicification. Silicification occurs in wall rock as quartz veinsand accompanied vein mineralization as quartz–fluorite–galena and quartz–galena veins (generally with open spacefilling texture) and/or is the dominant gangue mineral inmatrix of ore-bearing breccia with lesser amounts of kaolin-ite and calcite (Fig. 4A, B, and D). Quartz formed in two dis-tinct stages: early-stage quartz–sulfide veins and late quartzas veins and matrix.

(2) Argillic. Argillic is mainly observed within wall rocks nearvein mineralization. The alteration minerals, as determinedfrom petrographic and X-ray diffraction studies, includequartz, kaolinite, and illite. Minor clay minerals exist inmatrix of galena-bearing breccia.

Fig. 4. Photomicrographs of hydrothermal alteration assemblages from the Sechangi deXPL). B. Single grain of galena in silica matrix (SC30 sample-XPL). C. The calcite vein crosscin silica matrix (SC29 sample-XPL). E. The growth of galena along the borders, cracks, andlight (SC42 sample-PPL).

(3) Carbonatization. Carbonatization is late stage of alteration,occurring mainly in wall rocks as calcite veins associatedwith minor calcite in matrix of breccia. It is clear that thecalcite veins are younger than the late-stage quartz veins(Fig. 4C).

(4) Fluoritization. Fluoritization, which is mainly in the form ofgreen granular aggregates, show a close relationship withgalena mineralization. In some samples, galena is formedalong the borders, cracks, and cleavages of fluorite(Fig. 4E and F). The higher amounts of fluorite and galenagrains are brecciated in fault zone and re-deposited associ-ated with quartz ± Fe–oxide ± clay minerals ± calcite asmatrix (Fig. 3D). Although, quartz–flourite–galena veins areobserved in places.

4. Ore mineralogy

Fault systems are widespread in the Sechangi ore district,reflecting the regional tectonic history of the area. The Pb–Zn(–Cu) deposit in the study area occurs as ore vein situated alongfault zone that developed within the Late Eocene biotite–pyroxenemonzonite porphyry (Fig. 2). Ore/host-rock relations suggest thatpost-Late Eocene (younger than 37.5 Ma) faulting prepared anenvironment appropriate for mineralization. The strike and dip ofthe vein are N45�W and 80–85�NE, respectively. Vein thicknessvaries considerably from half a meter to 8 m with 1 to 3 m being

posit. A. Quartz–fluorite–galena vein with open space filling texture (SC53 sample-ut the late-stage quartz vein (SC62 sample-XPL). D. Fragments of galena and fluoritecleavages of fluorite (SC42 sample-XPL). F. The same photomicrograph in reflected

Fig. 5. The paragenetic relations for the Sechangi deposit.

6 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

the average, whereas the strike length can be up to 4 km. The orevein mainly contains brecciated host-rock fragments accompaniedby ore and gangue minerals. Although, massive, disseminated,vein, and vein-like structures textures are observed in places.

The minerals of the paragenesis were defined by means of oremicroscopy (XRD was also used in determining ore and clayminerals). The predominant primary sulfides are galena andsphalerite with minor chalcopyrite and pyrite. Cerussite, angle-site, covellite, malachite, hematite, and goethite are secondaryminerals that developed from the primary ones through weath-ering. Fluorite and quartz are the dominant gangue mineralswith lesser amounts of calcite, gypsum, kaolinite, and illite(Fig. 5).

Pyrite presents in minor amounts and occurs as euhedraland/or subhedral small grains (up to 0.2 mm) disseminated inhost rock and among other minerals. This mineral is partly orwholly transformed into goethite (Fig. 6A). Chalcopyrite is foundas vein and small to medium grains (0.1–0.6 mm) in malachiteand covellite and occurs as relicts. This mineral is mainly coatedby galena, indicating that it formed in earlier time than galena(Fig. 6B). Galena is the most abundant sulfide mineral and isthe only protected sulfide mineral in macroscopic scale that itis found as cumulates within the size range of 0.1–15 cm inthe ore. This mineral does not contain any kind of inclusions.Undulation and displacement of the triangular pits shows thatdeformations developed following deposition of galena(Fig. 6C and D). Galena mainly occurs as single grains in brec-ciated zone and some crystals are up to 2 mm in size.Although, quartz–fluorite–galena and quartz–galena veins areseen in the host rock. Cerussite and anglesite are observed asmostly overgrowths that form concentric textures along the bor-ders, cracks, and cleavages of galena, and also granular texturewith up to 1 mm sized anhedral crystals (Fig. 6E and F).Galena relicts are seen in the cerussite and anglesite (Fig. 6F).Covellite occurs at contacts between galena and gangue miner-als (Fig. 6G). Sphalerite crystals are mainly small (up to0.2 mm) in galena and the amount of them increase into thedepth (Fig. 6H).

The microscopic observations suggest that anglesite–cerussiteformed from galena and goethite formed from pyrite, which isrelated to weathering. Covellite, malachite, and hematite formedfrom supergene alterations of chalcopyrite.

5. Fluid inclusion studies

5.1. Sampling and methodology

Fluid inclusion data were obtained from surface, trenches, andshallower levels of the vertical shafts of the ore-bearing vein inthe area. Fifteen doubly polished wafers (150 lm thick) of fluoriteand early-stage quartz crystals prepared for fluid inclusion studieswere examined petrographically. They were studied usingstandard techniques (Roedder, 1958, 1972, 1984) and LinkamTHM 600 heating–freezing stage (from �190 to 600 �C) mountedon an Olympus TH4–200 microscope stage at FerdowsiUniversity of Mashhad, Iran.

The accuracy is estimated to be ±0.2 �C on freezing, ±2 �C below350 �C and about ±4 above 350 �C on heating. The stage was cali-brated at low temperatures with heptane (�90.6 �C), chloroform(�63.0 �C), chlorobenzene (�45.6 �C), n-dodecane (�9.6 �C) anddistilled water (0.0 �C). Calibration at 45 �C was made withMerck melting point standard 9645, and at 306 �C with sodiumnitrate. Salinity of the fluids trapped in fluid inclusions is calcu-lated based on the temperature of final ice melting (Tm) and theequation of Bodnar (1993). Densities are calculated using Flincorsoftware according to microthermometric data (Brown and Lamb,1989).

5.2. Morphology and inclusion types

Petrographic studies of fluid inclusions in fluorite and early-stage quartz were conducted to identify the hydrothermal fluidsand decipher fluid evolution processes. The fluorite and quartzsamples were dominated by primary fluid inclusions (with minorsecondary fluid inclusions) that are interpreted as representingthe fluids present at the time of hydrothermal mineral growth.Primary fluid inclusions are abundant with moderate to large size(typically 8–37 lm, average 22 lm) in fluorite samples (Fig. 6),whereas quartz contains fewer primary fluid inclusions with smallsize (typically 5–13 lm) (Table. 1). Fluid inclusion shapes includeelliptical, rod-shaped, round, irregular, and some directionalelongated. Fluid inclusions were distributed as clusters, singleinclusions, linear arrays, and along fractures or grain boundaries.

At room temperature, all of the measured inclusions are consid-ered primary because they are confined within specific growthzones of the host mineral (Roedder, 1984). The type of inclusionsin both fluorite and quartz are two-phase, liquid-rich with a 5–20% vapour in volume percentage inclusions that homogenize intoa liquid state upon heating (Fig. 7). The absence of liquid CO2 orclathrate formation during freezing experiments suggests thatnone of the inclusions contained significant quantities of CO2.Despite many measurements, fluid inclusion evidence for a fluidboiling process in the Sechangi samples is not clear.

5.3. Microthermometric measurements

Homogenization temperatures (Th) values range from 151 to352 �C (average 251 �C, n = 621) in fluorite and 161 to 215 �C (aver-age 185 �C, n = 58) in quartz (Table 1 and Fig. 8A). These Th valuesrepresent a minimum temperature of trapping of the hydrothermalfluid in the inclusion. The precise pressure during mineralization isunknown in the area. On the other hand, no boiling phenomena areseen in the fluid inclusions; according to the data of Hass (1971)this would indicate that if a hydrostatic head is assumed, thenthe temperature of mineralization could not have been more thanabout 330 �C. Thus the Th values are probably quite close to thetrue (‘‘trapping’’) temperatures, and only a minimal temperaturecorrection would be necessary. The average Th values of primary

Fig. 6. Photomicrographs of ore minerals from the Sechangi deposit (polished blocks, reflected light, in air). A. Pyrite is altered to goethite and malachite–Fe-oxide vein (SC7sample). B. Chalcopyrite crystal coated by galena and replaced by covellite along borders (SC48 sample). C. Undulation triangular pits in galena (SC29 sample). D. Undulationand displacement triangular pits in galena (SC34 sample-XPL). E. Cerrusite and anglesite occurrences along borders and fissures planes (SC41 sample). F. Smaller galena relictsin cerrusite–anglesite (SC52 sample). G. Covellite occurrences at contact between galena and gangue minerals (SC12 sample). H. Small grain of sphalerite in galena (SC35sample).

A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14 7

inclusions in fluorite and quartz indicate that the temperature ofthe mineralizing fluids was slightly higher during fluorite precip-itation in the earliest stage, and decreased through later stages ofmineralization (quartz precipitation) (Fig. 8A). Fluorite and galenashow a close relationship with another. The results ofmicrothermometric measurements confirm that the deposit canbe classified as a medium- to low-temperature deposit.

The first melting temperatures (Tfm) values of primaryinclusions in both fluorite and quartz crystals cluster between�55 and �52.2 �C (average �53.6 �C, n = 679). Comparison of thevalues to the eutectic temperatures of various water–salt systems

(Shephered et al., 1985; Gokce, 2000) suggests that they indicatehydrothermal fluids containing salts of CaCl2, MgCl2, and NaCl.No difference between samples collected from surface and mineexposures was detected; this indicates that the salt compositionof the fluid was homogenous during earlier and later mineralizingepisodes. These salt types and compositions may be a result of cir-culation of the mineralizing fluid through various Tertiary igneousrocks.

The final ice melting temperatures (Tmice) values range from 0.1to �12.6 �C (average �7.1 �C, n = 621) in fluorite and 0.1 to �6.4 �C(average �4.3 �C, n = 58) in quartz (Table. 1 and Fig. 8B). Salinities

Table 1Microthermometric data of primary fluid inclusions of the Sechangi deposit.

Sample no. Host mineral Number Size (lm) Th (�C) Tmice (�C) Salinity (NaCl wt.% equiv.) Density

SC18-2 Fluorite 40 8–30 151–265 �4 to �9.3 6.4–13.2 0.89–0.98SC32 Quartz 7 5–10 161–202 �4.2 to �6.4 6.7–9.7 0.93–0.97

Fluorite 21 7–20 184–245 �3.2 to �6.4 5.2–9.7 0.89–0.93SC44 Fluorite 40 10–35 190–301 �5 to �12.3 7.8–15.4 0.87–0.97SC26 Quartz 5 5–10 167–197 0.1 to �4.2 0–6.7 0.88–0.92

Fluorite 15 7–27 151–245 0.1 to �5.2 0.2–8.1 0.88–0.96SC37 Fluorite 37 12–30 165–279 �1 to �11.2 1.6–15.2 0.86–0.94SC46 Fluorite 79 11–37 171–341 �3.2 to �12.4 5.2–16.3 0.83–0.95SC38 Fluorite 43 9–29 176–300 �3.4 to �11.5 5.5–15.5 0.87–0.95SC30 Fluorite 103 8–32 166–352 �2.6 to �12.6 4.2–16.5 0.83–0.94SC18 Fluorite 32 8–26 202–312 �2.5 to �11.4 4.1–15.4 0.86–0.9SC29 Fluorite 54 12–36 222–324 �3.2 to �12.4 5.2–16.3 0.85–0.9SC33 Quartz 26 5–12 166–212 �2.2 to �5.5 3.6–8.5 0.91–0.95

Fluorite 26 9–31 200–252 �2.1 to �6.8 3.4–10.2 0.87–0.93SC42 Fluorite 40 8–34 184–285 �3.2 to �9.5 5.2–13.4 0.88–0.93SC47 Fluorite 39 11–27 214–330 �3.2 to �12.4 5.2–16.3 0.85–0.9

Quartz 11 5–13 175–214 �3.2 to �5.3 5.2–8.2 0.91–0.95SC48 Quartz 8 5–10 174–215 �2.2 to �5.6 3.6–8.7 0.91–0.95

Fluorite 27 10–27 254–340 �6.2 to �12.2 9.5–16.2 0.84–0.9SC45 Fluorite 25 8–29 216–289 �4.3 to �9.4 6.8–13.3 0.87–0.89

Th, homogenization temperature; Tm, temperature for final ice melting.

Fig. 7. Micropictures of liquid–vapour inclusions in the Sechangi deposit.

Fig. 8. Histogram showing the thermodynamic data of primary fluid inclusions in the Sechangi deposit. A. Homogenization temperature histogram, B. Final ice meltingtemperature histogram, and C. Salinity (wt.% NaCl equivalent) histogram.

8 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

Table 2Sulfur isotope compositions of the Sechangi deposit.

Sampleno.

Mineral d34Ssulfide

(‰)CDT

Th (�C) (fluidcalculated)

1000 lna (Liand Liu, 2006)

d34SH2S

(‰)

SC18 Galena �9.6 267 �2.19 �7.4SC18-2 Galena �9.1 201 �2.85 �6.2SC26 Galena �9.0 202 �2.83 �6.2SC29 Galena �8.3 277 �2.11 �6.2SC30 Galena �9.7 292 �2.00 �7.7SC32 Galena �8.6 217 �2.66 �5.9SC33 Galena �12.3 224 �2.39 �9.9SC42 Galena �9.6 247 �2.37 �7.2SC44 Galena �8.3 245 �2.38 �5.9SC45 Galena �8.8 257 �2.28 �6.5SC46 Galena �9.1 253 �2.31 �6.8SC47 Galena �8.8 281 �2.08 �6.7SC48 Galena �9.8 290 �2.02 �7.8

Fig. 9. Histogram of H2S d34S in equilibrium with galena at a given temperatures(using either the average temperature of the hydrothermal fluid during the galenamineralization episode as 201–290 �C, using the Li and Liu (2006) equation).

A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14 9

(wt.% NaCl equivalent) of ore-forming fluids can be calculatedaccording to the relationship between final ice melting tempera-tures and salinities (Hall and Sterner, 1988). The salinities of thehydrothermal fluids were calculated using the equation byBodnar (1993), and yielded wt.% NaCl equivalents as follows:0.2–16.5 wt.% NaCl equivalent (average 10.4 wt.% NaCl equivalent,n = 621) in fluorite and 0–9.7 wt.% NaCl equivalent (average6.7 wt.% NaCl equivalent, n = 58) in quartz (Table. 1 and Fig. 8C).The average salinity values of primary inclusions in fluorite andquartz indicate that the salinity of the mineralizing fluids wasslightly higher during fluorite precipitation in the earliest stage,and decreased through later stages of mineralization (quartzprecipitation) (Fig. 8C). These salinity data demonstrate that theore-forming fluids were medium- to low-salinity fluids. Thedensity of ore-forming fluids can be calculated using the equationproposed by Brown and Lamb (1989) and the densities in thisstudy range from 0.83 to 0.98 g/cm3, with an average value of0.9 g/cm3, in fluorite and 0.88 to 0.97 g/cm3, with an average valueof 0.93 g/cm3, in quartz (Table. 1).

6. Sulfur isotopic compositions

6.1. Analytical method

Galena was the only useful sulfide mineral for isotopic analysisin terms of sulfur abundance and microscopic features. The d34S ofgalena samples from the Sechangi was analyzed in an attempt tointerpret the origin of the deposit. The amount of other sulfideminerals was too small for mineral separation work and the sulfurisotope analyses were not preformed. Ore samples of galenaselected for the fluid inclusion study (showing closely relationshipwith fluorite) were also used for sulfur isotopic analysis. Thesesamples were collected from trenches and shallower levels of thevertical shafts and were separated from monomineralic samplesusing a microdrill under a binocular microscope. The microdrillwas cleaned between each sample extraction to avoid contam-ination. Sulfur isotope analyses were done at the EnvironmentalIsotope Laboratory of the Arizona University. The d34S was mea-sured on SO2 gas in a continuous-flow gas-ratio mass spectrometer(ThermoQuest Finnigan Delta PlusXL). Samples were combusted at1030 �C with O2 and V2O5 using an elemental analyzer (Costech)coupled to the mass spectrometer. Standardization is based oninternational standards OGS-1 and NBS123, and several othersulfide and sulfate materials that have been compared betweenlaboratories. Results are expressed in the standard per mil notationrelative to the international Canyon Diablo Troilite (CDT)standard. Calibration is linear in the range �10‰ to +30‰. Theaccuracy is estimated to be ±0.15 or better (1r).

6.2. Results

The sulfur isotopic compositions of metallic minerals (d34S) andore-forming fluids (d34SRS) provide constraints on possible geologi-cal sources of sulfur and other metallogenic elements and help todecipher the conditions of formation of sulfides in ore deposits(Ohmoto, 1972; Ohmoto and Goldhaber, 1997). Sulfur isotopicresults are listed in Table 2. The sulfur isotopic compositions (i.e.d34S) of these samples were �12.3‰ to �8.3‰, with an averagevalue of �9.3‰ (n = 13). In term of d34S values, there is not a sig-nificant difference between the analyzed samples. Under thephysical and chemical conditions (T < 300 �C, low pH and Eh)envisaged for the main stage fluids the major sulfur species wouldbe H2S (Ohmoto and Rye, 1979). At these temperatures, sulfidedominance results in sulfide mineral d34S values being close tothe original fluid d34SH2S (Ohmoto and Rye, 1979). The d34SCDT val-ues of H2S in equilibrium with galena were estimated to be in therange of �9.9‰ to �5.9‰ (average �7‰) by evaluating the d34Svalues of galena and the average temperature of the hydrothermalfluid during the galena mineralization episode as 201–290 �C(determined by homogenization temperature measurements dur-ing fluid inclusion studies in the fluorite samples as closelyrelationship with galena), using the equation suggested by Li andLiu (2006) (Table 2) (Fig. 9).

7. Discussion

7.1. Evolution of ore-forming fluids

Many studies have demonstrated the importance of isotopicanalyses in elucidating the origin of hydrothermal fluids (Crissand Farquhar, 2008; Huang et al., 2011). Galena in the vein atthe Sechangi ranges in d34S values from around �12.3‰ to�8.3‰ (average �9.3‰) and the d34SH2S in equilibrium with galenawere estimated to be in the range of �9.9‰ to �5.9‰ (average�7‰). The absence of sulfate minerals in the vein suggests thatsulfur was transported in a reduced state, most likely as HS�, andthat the negative d34S values cannot be attributed to fractionationprocesses. The d34S values do not point to a specific source for sul-fur. The negative d34S values do not necessarily rule out a directmagmatic source, as a wide spread in d34S values, �10‰ to over+10‰ has been indicated for much arc- and rift-related magma

Fig. 10. Pressure–temperature diagram showing phase relationships in the NaCl–H2O system at lithostatic and hydrostatic pressures (Fournier, 1999). L = liquid,V = vapor, H = halite. Thin dashed lines are contours of constant wt percent NaCldissolved in brine. Filled gray line indicates granite minimum melting curve. Filleddark line shows the three-phase boundary, L + V + H, for the system NaCl–KCl–H2Owith Na/K in solution fixed by equilibration with albite and K-feldspar at theindicated temperatures. Location of fluorite and quartz fluid inclusions plotted on it.

Fig. 12. Homogenization temperature versus salinity diagram for fluid inclusions inthe Sechangi deposit. Fields for various fluid types after Beane (1983).

10 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

(Hoefs, 2009). The relatively low salinities argue against a directmagmatic source for fluids. A possible source for 34S-depleted sul-fur would be sulfide-bearing sedimentary rocks. However, suchrocks are not identified in the area around the deposit. We suggestthat sulfur was likely supplied through leaching of the older vol-canic and plutonic rocks. Oxygen and hydrogen isotope data arerequired to be able to further discuss the source of the ore fluids.

Our analyses of fluid inclusions of the Sechangi Pb–Zn (–Cu)deposit revealed that the ore-forming fluids were medium–lowtemperature and medium–low salinity H2O–NaCl system fluid.The pressure determined for Sechangi deposit is ca. <20 MPa,which is equivalent to a depth of approximately <2 km and<1 km, assuming hydrostatic and lithostatic pressure, respectively(Fig. 10). This implies that the vein was formed at shallow depth.

Fig. 11. Homogenization temperature versus salinity of fluid inclusions in the Sechangi dfrom Shephered et al. (1985). Trend 1 represents primitive fluid A mixed with cold and lowith different salinity fluid B, trend 4 represents the salinity of residual phase increased,necking of the fluid inclusion, trend 7 represents leakage of fluid inclusions during heat

On the fluid evolution diagram (Fig. 11), homogenization tem-perature shows a positive correlation with fluid salinity. Previousstudies have shown that homogenization temperature and fluidsalinity, as well as fluid salinity and enthalpy, show positivecorrelation the process of fluid mixing, whereas the data shownegative correlation trends during fluid boiling (Shephered et al.,1985). According to the evidence for fluid mixing outlined byZhang (1997), the characteristics of fluid evolution of theSechangi deposit are consistent with a fluid-mixing scenario.Specifically, the salinity-homogenization temperature diagramshowed a fluid evolution trend shifting from relatively high to rela-tively low homogenization temperature and salinity (Fig. 11). Thehomogenization temperature and salinity of the mineralizing flu-ids was slightly higher during fluorite precipitation in the earlieststage associated with galena, and decreased through later stagesof mineralization (quartz precipitation) (Fig. 11). Based on thesearguments, it is suggested that fluid mixing occurred during thefluid evolution. It is well known that this mechanism can play animportant role in explaining the origin and formation of largehydrothermal ore deposits (Zhu et al., 2001; Cooke and McPhail,

eposit. Several possible trends of fluid evolution in a temperature–salinity diagramw salinity fluid B, trends 2 and 3 represent the result of fluid A isothermally mixingcaused by boiling of fluid A, trend 5 represents cooling of fluid A, trend 6 representsing.

Fig. 13. Homogenization temperature–salinity diagram illustrating typical ranges for inclusions from different deposit types (modified after Wilkinson, 2001). The mostmicrothermometric data of fluid inclusions in the Sechangi deposit plot in the epithermal deposit field.

A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14 11

2001; Fan et al., 2011; Gu et al., 2011; Zhai et al., 2013), and itseems clear for the Sechangi deposit that fluid mixing played animportant role. Also, relationship between homogenizationtemperature, salinity, and fields for various fluid types (Fig. 12)probably indicates that magmatic–meteoric mixing fluid wasresponsible for ore mineralization at the Sechangi. Although,oxygen and hydrogen isotope data are required to be confirm thisclaim. There is also overlap with metamorphic fluids in Fig. 12, butthere is no evidence of metamorphic rocks or regional metamor-phism in the area. Fig. 13 represents the most of homogenizationtemperature and salinity data of fluid inclusions plotted in the fieldof epithermal deposit.

Fig. 14. Model for formation of the Sechangi

7.2. Mineralization model and genetic type

The Lut block has a great potential for porphyry Cu and Cu–Au,related-epithermal Au, and Cu–Pb–Zn vein-type deposits due toits past subduction zone tectonic setting between the Lut and theAfghan blocks, which led to extensive magmatic activity formingigneous rocks of different geochemical compositions (MalekzadehShafaroudi, 2009; Karimpour et al., 2011). A few detailed studieswere reported about genetic model and formation of base-metalepithermal deposits in the Lut block (Lotfi, 1982; Mehrabi andTalefazel, 2011; Mehrabi et al., 2011; Mirzaei Rayeni et al., 2012;Malekzadeh Shafaroudi and Karimpour, 2013b).

deposit (see text for detail-not to scale).

12 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

The Sechangi deposit is one of the many epithermal Pb–Zn(–Cu) deposits, which is occurred in metallogenic epoch of theLut block (Middle Eocene to Lower Oligocene), as suggested byKarimpour et al. (2012). A geologic and genetic relation betweenore vein and Late Eocene biotite–pyroxene monzonite porphyryappears to be lacking. Therefore, the age of mineralization isyounger than 37.5 Ma. On the basis of the regional episodes of pro-lific magmatic activity, a widespread episode of mineralization,and the specifics of ore deposit geology, we consider the formationof the Sechangi deposit to be directly linked to volcanic–subvol-canic hydrothermal activity of Late Eocene (younger than37.5 Ma) and/or a few after it period. Coupled with late-stage addi-tion of meteoric water, these magmatic fluids created favorableconditions for the metallogenic elements to accumulate and pre-cipitate during the formation of such a relatively large ore deposit.During the Late Eocene and after it periods, intense magmaticactivity in the Sechangi region resulted in the generation of a seriesof calk-alkaline magmas. In addition, NW–SE and minor NE–SW-trending faults were formed due to these intense tectonic andmagmatic activities. Subvolcanic intrusions were formed frommagmas ascending along favorable structural pathways (such asfaults or fractures).

The early ore-forming fluids had relatively high temperature,salinity, and concentration of metallogenic elements such as Pb2+,Zn2+, and Cu2+, and were formed by magmatic differentiation andby the evolution of volcanic and subvolcanic fluids (Fig. 14). Ore-forming fluids ascended along favorable structures and reacted withwall rock, changing the physicochemical conditions and isotopiccompositions of the fluids. In addition, the fluids seem to haveascended to a sufficiently shallow depth to allow for efficient fluidmixing with meteoric water (Fig. 14). Through the reaction ofmineralizing fluids with wall rock and heat recharge by magma orgeothermal anomalies in the region, the meteoric water, which ini-tially had relatively low temperature and salinity, might haveextracted significant amounts of metallogenic materials from hostrock. Through mixing between fluids with different properties andmetal contents, these combined fluids changed the conditions ofthe ore-forming fluid system, destroying the chemical equilibriumof solutions and initiating important chemical reactions, ultimatelyresulting in the precipitation from solution of metallogenic materi-als during the formation of this relatively large ore deposit (Fig. 14).Consequently, fluid mixing seems to represent an important mecha-nism for explaining the formation of the Sechangi deposit, whichcan be confirmed by oxygen and hydrogen isotope data. In addition,the genetic type of the Sechangi Pb–Zn (–Cu) deposit is classified asa volcanic–subvolcanic hydrothermal-related vein deposit.

8. Conclusions

(1) Sechangi Pb–Zn (–Cu) deposit occurs in an area covered bythe Eocene felsic-intermediate volcanic and intrusive rocks,in the western Lut block. The distribution of ore body withinthe area was controlled primarily by fault. The alterationzone is marked by an assemblage of quartz, kaolinite, illite,and calcite. The ore vein contains galena and sphalerite withminor chalcopyrite and pyrite as hypogene minerals andcerussite, anglesite, covellite, malachite, hematite, andgoethite as secondary minerals. Fluorite and quartz are thedominant gangue minerals.

(2) The d34S values for Galena samples from the Sechangi fall inthe range �12.3‰ to �8.3‰. The d34SCDT values of H2S inequilibrium with galena were estimated to be in the rangeof �9.9‰ to �5.9‰ (average �7‰). The sulfur isotope ratioscould be explained by derivation from a magmatic source, orleaching of sulfides from the country rocks.

(3) Fluid inclusion data indicate that the ore forming fluids con-tain significant quantities of divalent cations (CaCl2 andMgCl2), along with NaCl. The homogenization of liquid tem-peratures are in the range 151–352 �C (average 251 �C) influorite and decrease down to 161–215 �C (average 185 �C)in quartz. The salinity of fluids was in the range of 0.2–16.5 wt.% NaCl equivalent (average 10.4 wt.% NaCl equiva-lent) in fluorite and 0–9.7 wt.% NaCl equivalent (average6.7 wt.% NaCl equivalent) in quartz. Microthermometricstudies and composition measurements of fluid inclusionsshow that the general features of the ore-forming fluidsinvolved medium- to low-temperature and medium- tolow-salinity in the NaCl–H2O system.

(4) The positive correlation between homogenization tempera-ture and fluid salinity, combined with ore deposit geology,provides evidence that aqueous mixing was an importantprocess in the evolution of the ore-forming fluids. The lattercan be divided into two end-member compositions:magmatic and meteoric. Mixing of fluids with differentproperties and metal contents was an important factor con-tributing to the formation of Pb–Zn (–Cu) ores in theSechangi deposit. The sulfur isotopic evidence suggests thattwo or more fluids existed during the formation of theSechangi deposit.

(5) The formation of the Sechangi Pb–Zn (–Cu) ore deposit wascontrolled by hydrothermal fluids related to Late Eocene(younger than 37.5 Ma) and/or a few later magmatic activityin the Lut block. Mineralization was a product of magmatismderived from a mantle source. In terms of the genetic type ofdeposit, the Sechangi is classified as a volcanic–subvolcanichydrothermal-related vein deposit. Prospecting for newdeposits should be concentrated in the Lut block.

Acknowledgments

The Research Foundation of Ferdowsi University of Mashhad,Iran, supported this study (Project No. 22745.2). Thanks to Dr.Chris Eastoe (University of Arizona) for the S-isotope analysesand anonymous reviewers for their constructive and helpfulreviews on this manuscript.

References

Alavi, M., 1996. Tectonostratigraphy synthesis and structural style of the AlborzMountain system in northern Iran. J. Geodyn. 21, 1–33. http://dx.doi.org/10.1016/0264-3707(95)00009-7.

Arjmandzadeh, R., Karimpour, M.H., Mazaheri, S.A., Santos, J.F., Medina, J.M.,Homam, S.M., 2011. Sr–Nd isotope geochemistry and petrogenesis of the Chah-Shaljami granitoids (Lut block, eastern Iran). J. Asian Earth Sci. 41, 283–296.http://dx.doi.org/10.1016/j.jseaes.2011.02.014.

Azimi, M.A., Saeedi, A., 1975. 1:100,000 Geological Quadrangle Map of Iran No.7655: Sechangi. Tehran, Geological Survey of Iran, 1 Sheet.

Bagheri, B., 2008. Anticlockwise rotation of the Central-East Iranian Microcontinentand the Eurasian-Indian collision. In: 33rd International Geological Congress,Oslo, pp. 6–14.

Bagheri, B., Stampfli, G.M., 2008. The Anarak, Jandaq and Posht-e-Badammetamorphic complexes in central Iran: new geological data, relationshipsand tectonic implications. Tectonophysics 451, 123–155. http://dx.doi.org/10.1016/j.tecto.2007.11.047.

Bazin, D., Hubner, H., 1969. Copper Deposits in Iran. Geological Survey of Iran,International Report. No. 13, pp. 87–93.

Beane, R.E., 1983. The Magmatic–Meteoric Transition. Geothermal ResourcesCouncil, Special Report 13, pp. 245–253.

Berberian, M., 1973. Structural History of Lut Zone. Geological Survey of Iran,Tehran, Internal Report 34.

Berberian, M., 1983. Continental Deformation on the Iranian Plateau. GeologicalSurvey of Iran, Report. No. 52.

Berberian, F., Muir, I.D., Pankhurst, R.J., Berberian, M., 1982. Late Cretaceous andearly Miocene Andean type plutonic activity in northern Makran and centralIran. J. Geol. Soc. London 139, 605–614.

A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14 13

Besse, J., Torcq, F., Gallet, Y., Ricou, L.E., Krystyn, L., Saidi, A., 1998. Late Permian toLate Triassic palaeomagnetic data from Iran: constraints on the migration of theIranian block through the Tethyan Ocean and initial destruction of Pangaea.Geophys. J. Int. 135, 77–92. http://dx.doi.org/10.1046/j.1365-246X.1998.00603.x.

Bodnar, R.J., 1993. Revised equation and table for determining the freezing pointdepression of H2O–NaCl solutions. Geochim. Cosmochim. Acta 57, 683–684.http://dx.doi.org/10.1016/0016-7037(93)90378-A.

Boomeri, M., Nakashima, K., Lentz, D.R., 2009. The Miduk porphyry Cu deposit,Kerman, Iran: a geochemical analysis of the potassic zone including halogenelement systematics related to Cu mineralization processes. J. Geochem. Explor.103, 17–29. http://dx.doi.org/10.1016/j.gexplo.2009.05.003.

Brown, P.E., Lamb, W.M., 1989. P–V–T properties of fluids in the systemH2O ± CO2 ± NaCl: new graphic presentations and implications for fluidinclusion studies. Geochim. Cosmochim. Acta 53, 1209–1221. http://dx.doi.org/10.1016/0016-7037(89)90057-4.

Calagari, A.A., 2003. Stable isotope (S, O, H and C) studies of the phyllic and potassic-phyllic alteration zones of the porphyry copper deposit at Sungun, EastAzarbaijan, Iran. J. Asian Earth Sci. 21, 767–780. http://dx.doi.org/10.1016/S1367-9120(02)00073-1.

Calagari, A.A., Polyad, A., Patrick, R.A.D., 2001. Veinlets and micro-veinlets studies inSungun porphyry deposit, east Azarbaijan. Iranian J. Geosci. 10, 70–79 (inPersian with English abstract).

Camp, V., Griffis, R., 1982. Character, genesis and tectonic setting of igneous rocks inthe Sistan suture zone, eastern Iran. Lithos 15, 221–239. http://dx.doi.org/10.1016/0024-4937(82)90014-7.

Cooke, D.R., McPhail, D.C., 2001. Epithermal Au–Ag–Te mineralization, Acupan,Baguio district, Philippines: numerical simulations of mineral deposition. Econ.Geol. 96, 109–131, 0361-0128/01/3123/109-23$6.00.

Criss, R.E., Farquhar, J., 2008. Abundance, notation, and fractionation of light stableisotopes. Rev. Mineral. Geochem. 68, 15–30.

Dehghani, G., 1981. Schwerefeld und Krustenaufbau im Iran. HumburgerGeophysics. Einzelscher., R. A., H., 54, S., Hamburg.

Dercourt, J. et al., 1986. Geological evolution of the Tethys belt from the Atlantic tothe Pamirs since the Lias. Tectonophysics 123, 241–315. http://dx.doi.org/10.1016/0040-1951(86)90199-X.

Doglioni, C., Tonarini, S., Innocenti, F., 2009. Mantle wedge asymmetries andgeochemical signatures along W- and E–NE directed subduction zones. Lithos113, 179–189. http://dx.doi.org/10.1016/j.lithos.2009.01.012.

Eftekharnejad, J., 1981. Tectonic division of Iran with respect to sedimentary basins.J. Iranian Petrol. Soc. 82, 19–28 (in Persian with English abstract).

Fan, H.R., Hu, F.F., Wilde, S.A., Yang, K.F., Jin, C.W., 2011. The Qiyugou gold–bearingbreccia pipes, Xiong’ershan region, central China: fluid–inclusion and stable–isotope evidence for an origin from magmatic fluids. Int. Geol. Rev. 53, 25–45.http://dx.doi.org/10.1080/00206810902875370.

Forster, H., 1978. Mesozoic–Cenozoic metallogenesis in Iran. J. Geol. Soc. London135, 443–445. http://dx.doi.org/10.1144/gsjgs.135.4.0443.

Fournier, R.O., 1999. Hydrothermal processes related to movement of fluid fromplastic into brittle rock in the magmatic-epithermal environment. Econ. Geol.94, 1193–1212.

Geological Survey of Iran, 1983. 1:250,000 Geological Quadrangle Map of Iran No.K6: Gonabad. Tehran, Geological Survey of Iran, 1 Sheet.

Geological Survey of Iran, 1989. 1:2,500,000 Geological Map of Iran. Tehran,Geological Survey of Iran, 1 Sheet.

Geological Survey of Iran, 1992a. 1:250,000 Geological Quadrangle Map of Iran No.K8: Birjand. Tehran, Geological Survey of Iran, 1 Sheet.

Geological Survey of Iran, 1992b. 1:250,000 Geological Quadrangle Map of Iran No.K9: Dehsalm (Chah Vak). Tehran, Geological Survey of Iran, 1 Sheet.

Geological Survey of Iran, 2009. 1:5,000,000 International Geological Map of theMiddle East, 2nd ed. Tehran, Geological Survey of Iran, 1 Sheet.

Geological Survey of Iran, 1969. 1:250,000 Geological Quadrangle Map of Iran No.J7: Boshruyeh. Tehran, Geological Survey of Iran, 1 Sheet.

Geological Survey of Iran, 1977. 1:250,000 Geological Quadrangle Map of Iran No.J6: Ferdows. Tehran, Geological Survey of Iran, 1 Sheet.

Ghasemi, A., Talbot, C.J., 2006. A new tectonic scenario for the Sanandaj-Sirjan zone(Iran). J. Asian Earth Sci. 26, 683–693. http://dx.doi.org/10.1016/j.jseaes.2005.01.003.

Gokce, A., 2000. Ore Deposits. Cumhuriyet University Publication 100, pp. 1–336.Golonka, J., 2004. Plate tectonic evolution of the southern margin of Eurasia in the

Mesozoic and Cenozoic. Tectonophysics 381, 235–273. http://dx.doi.org/10.1016/j.tecto.2002.06.004.

Gu, L.X., Wu, C.Z., Zhang, Z.Z., Franco, P., Ni, P., Chen, P.R., Xiao, X.J., 2011.Comparative study of ore-forming fluids of hydrothermal copper–gold depositsin the lower Yangtze River Valley, China. Int. Geol. Rev. 53, 477–498. http://dx.doi.org/10.1080/00206814.2010.533873.

Hall, D.L., Sterner, S.M., 1988. Freezing point depression of NaCl–KCl–H2O solution.Econ. Geol. 83, 197–202.

Hass, J.L., 1971. The effect of salinity on the maximum thermal gradient of ahydrothermal system at hydrostatic pressure. Econ. Geol. 66, 940–946.

Hassanzadeh, J., Ghazi, A.V., Axen, G., Guest, B., 2002. Oligo-Miocene Mafic AlkalineMagmatism in North and Northwest of Iran: Evidence for the Separation of theAlborz from the Urumieh-Dokhtar Magmatic Arc. Geological Society of America,Abstract.

Hoefs, J., 2009. Stable Isotope Geochemistry. Springer-Verlag, Berlin.Huang, D.Z., Wang, X.Y., Yang, X.Y., Li, G.M., Huang, S.Q., Liu, Z., Peng, Z.H., Qiu, R.L.,

2011. Geochemistry of gold deposits in the Zhangbaling tectonic belt, Anhui

province, China. Int. Geol. Rev. 53, 612–634. http://dx.doi.org/10.1080/00206814.2010.496225.

Jung, D., Keller, J., Khorasani, R., Marcks, Chr., Baumann, A., Horn, P., 1983. Petrologyof the Tertiary Magmatic Activity the Northern Lut Area, East of Iran. Ministry ofMines and Metals, Geological Survey of Iran, Geodynamic Project (Geotraverse)in Iran, No. 51, pp. 285–336.

Karimpour, M.H., 2004. Mineralogy, Alteration, source rock, and tectonic setting ofiron-oxides Cu–Au deposits and examples of Iran. In: 11th IranianCrystallography and Mineralogy Society of Iran Conference, University ofYazad, pp. 184–189.

Karimpour, M.H., Stern, C.R., Farmer, L., Saadat, S., Malekzadeh Shafaroudi, A., 2011.Review of age, Rb–Sr geochemistry and petrogenesis of Jurassic to Quaternaryigneous rocks in Lut block, Eastern Iran. J. Geopersia 1, 19–36.

Karimpour, M.H., Malekzadeh Shafaroudi, A., Stern, C.R., Farmer, L., 2012.Petrogenesis of Granitoids, U–Pb zircon geochronology, Sr–Nd isotopiccharacteristic, and important occurrence of Tertiary mineralization within theLut Block, eastern Iran. J. Econ. Geol. 4, 1–27 (in Persian with English abstract).

Karimzadeh Somarin, A., 2004. Geochemical effects of endoskarn formation in theMazraeh Cu–Fe skarn deposit in northwestern Iran. Geochem. Explor. Environ.Anal. 4, 307–315. http://dx.doi.org/10.1144/1467-7873/04-209.

Karimzadeh Somarin, A., Hosseinzadeh, G., 2002. Mineralogy of the Anjerd SkarnDeposit, Ahar Region, NW Iran. International Mineralogical Association,Edinburgh, Scotland.

Kluyver, H.M., Tirrul, R., Chance, P.N., Johns, G.W., Meixner, H.M., 1978. ExplanatoryText of the Naybandan Quadrangle Map. Geological Survey of Iran (UnpublishedReport).

Li, Y., Liu, J., 2006. Calculation of sulfur isotope fractionation in sulfides. Geochim.Cosmochim. Acta 70, 1789–1795. http://dx.doi.org/10.1016/j.gca.2005.12.015.

Lotfi, M., 1982. Geological and Geochemical Investigation on the Volcanogenic Cu–Pb–Zn–Sb Ore Mineralization in the Shurab-Gale Chah and North West of Khur.Unpublished PhD Thesis, University of Hamburg, Hamburg, pp. 1–152.

Mahmoudi, S., Masoudi, F., Corfu, F., Megrabi, B., 2010. Magmatic and metamorphichistory of the Deh-Salm metamorphic Complex, Eastern Lut block, (EasternIran), from U–Pb geochronology. Int. J. Earth Sci. (Geol Rundsch) 99, 1153–1165.http://dx.doi.org/10.1007/s00531-009-0465-x.

Malekzadeh Shafaroudi, A., 2009. Geology, Mineralization, Alteration,Geochemistry, Microthermometry, Radiogenic Isotopes, Petrogenesis ofIntrusive Rocks and Determination of Source of Mineralization in Maherabadand Khopik Prospect Area, South Khorasan Province. Unpublished PhD Thesis,Ferdowsi University of Mashhad, Mashhad, Iran, pp. 1–536.

Malekzadeh Shafaroudi, A., Karimpour, M.H., 2013a. Hydrothermal alterationmapping in northern Khur, Iran, using ASTER image processing: a new insightto the type of copper mineralization in the area. Acta Geol. Sinica 87, 830–842.http://dx.doi.org/10.1111/1755-6724.12092.

Malekzadeh Shafaroudi, A., Karimpour, M.H., 2013b. Geology, mineralization, andfluid inclusion studies of the Howz-e-Rais lead–zinc–copper deposit, EasternIran. J. Adv. Appl. Geol. 6, 63–73 (in Persian with English abstract).

Malekzadeh Shafaroudi, A., Karimpour, M.H., Golmohammadi, A., 2013a. Zircon U–Pb geochronology and petrology of intrusive rocks in the C-North and Baghakdistricts, Sangan iron mine, NE Iran. J. Asian Earth Sci. 64, 256–271. http://dx.doi.org/10.1016/j.jseaes.2012.12.028.

Malekzadeh Shafaroudi, A., Karimpour, M.H., Esfandiarpour, A., 2013b. Petrographyand petrogenesis of intrusive rocks in northeast of Nayband, East of Iran.Petrology 16, 105–124 (in Persian with English abstract).

Mazloumi, A., Karimpour, M.H., Rasa, I., Rahimi, B., Vosoghi Abedini, M., 2009. Kuh-e-Zar gold deposit of Torbat-e-Hydarieh: new model of gold mineralization.Iranian J. Crystallogr. Mineral. 16, 364–376 (in Persian with English abstract).

Mehrabi, B., Talefazel, E., 2011. The role of magmatic and meteoric water mixing inmineralization of Shurab polymetal ore deposit, South of Ferdows: isotopegeochemistry and microthermometry evidences. Iranian J. Crystallogr. Mineral.19, 121–130 (in Persian with English abstract).

Mehrabi, B., Talefazel, E., Nokhbatolfoghahai, A., 2011. Disseminated, veinlet, andvein Pb–Zn, Cu and Sb polymetallic mineralization in the GaleChah-Shurabmining district, Iranian East Magmatic Assemblage (IEMA). J. Econ. Geol. 3, 61–77 (in Persian with English abstract).

Mirzaei Rayeni, R., Ahmadi, A., Mirnejad, H., 2012. Mineralogy and fluid inclusionstudies in Mahour polymetal deposit, east of Lut block, Central Iran. Iranian J.Crystallogr. Mineral. 20, 307–318 (in Persian with English abstract).

Mohajjel, M., Fergusson, C.L., Sahandi, M.R., 2003. Cretaceous–Tertiary convergenceand continental collision, Sanandaj-Sirjan zone, western Iran. J. Asian Earth Sci.21, 397–412. http://dx.doi.org/10.1016/S1367-9120(02)00035-4.

Nabavi, M., 1976. An Introduction to the Geology of Iran. Geological Survey of IranPublication, pp. 1–109 (in Persian).

Ohmoto, H., 1972. Systematics of the sulfur and carbon in hydrothermal oredeposits. Econ. Geol. 67, 551–579.

Ohmoto, H., Goldhaber, M.B., 1997. Sulfur and carbon isotopes. In: Barnes, H.L. (Ed.),Geochemistry of Hydrothermal ore Deposits. John Wiley and Sons, New York,pp. 517–611.

Ohmoto, H., Rye, R.O., 1979. Isotopes of sulfur and carbon. In: Barnes, H.L. (Ed.),Geochemistry of Hydrothermal ore Deposits. Wiley, New York, pp. 509–567.

Richards, J.P., Spell, T., Rameh, E., Razique, A., Fletcher, T., 2012. High Sr/Y magmasreflect arc maturity, high magmatic water content, and porphyry Cu ± Mo ± Aupotential: examples from the tethyan arcs of central and eastern Iran andwestern Pakistan. Econ. Geol. 107, 295–332, 0361-0128/12/4013/295-38.

Roedder, E., 1958. Technique for the extraction and partial chemical analysis offluid–filled inclusions from minerals. Econ. Geol. 53, 235–269.

14 A. Malekzadeh Shafaroudi, M.H. Karimpour / Journal of African Earth Sciences 107 (2015) 1–14

Roedder, E., 1972. Composition of Fluid Inclusions. US Geological SurveyProfessional Paper Jj-440 1972, pp. 1–164.

Roedder, E., 1984. Fluid Inclusions. Reviews in Mineralogy, v. 12, MineralogicalSociety of America, Washington, DC, pp. 1–644.

Saccani, E., Delavari, M., Beccaluva, L., Amini, S.A., 2010. Petrological andgeochemical constraints on the origin of the Nehbandan ophiolitic complex(eastern Iran): implication for the evolution of the Sistan Ocean. Lithos 117,209–228. http://dx.doi.org/10.1016/j.lithos.2010.02.016.

Samani, B., Ashtari, S., 1992. Geological evolution of Sistan and Baluchestan area.Iranian J. Geosci. 4, 72–85 (in Persian with English abstract).

Sengör, A.M.C., Natalin, B.A., 1996. Paleotectonics of Asia: fragment of a synthesis.In: An, Y., Harrison, T.M. (Eds.), The Tectonic Evolution of Asia. CambridgeUniversity Press, Cambridge, pp. 486–640.

Shafiei, B., Haschke, M., Shahabpour, J., 2009. Recycling of orogenic arc crust triggersporphyry Cu mineralization in Kerman Cenozoic arc rocks, southeastern Iran.Miner. Deposita 44, 265–283. http://dx.doi.org/10.1007/s00126-008-0216-0.

Shahabpour, J., 2005. Tectonic evolution of the orogenic belt in the region locatedbetween Kerman and Neyriz. J. Asian Earth Sci. 24, 405–417. http://dx.doi.org/10.1016/j.jseaes.2003.11.007.

Shahabpour, J., 2007. Island-arc affinity of the Central Iranian Volcanic Belt. J. AsianEarth Sci. 30, 652–665. http://dx.doi.org/10.1016/j.jseaes.2007.02.004.

Shephered, T.J., Rankin, A.H., Alderton, D.H.M., 1985. A Practical Guide to FluidInclusion Studies. Blackie, London, UK.

Stocklin, J., 1968. Structural history and tectonics of Iran: a review. Bull. Am. Assoc.Petrol. Geol. 52, 1239–1258.

Stocklin, J., Nabavi, M.H., 1973. Tectonic Map of Iran. Geological Survey of Iran.Tarkian, M., Lotfi, M., Baumann, A., 1984. Magmatic copper and lead–zinc ore

deposits in the Central Lut, East Iran. Neues Jahrb. Geol. Paläontol, Abh. 168,497–523.

Tirrul, R., Bell, I.R., Griffis, R.J., Camp, V.E., 1983. The Sistan suture zone of easternIran. Geol. Soc. Am. Bull. 94, 134–156. http://dx.doi.org/10.1130/0016-7606(1983) 94<134:TSSZOE>2.0.CO;2.

Waterman, G.C., Hamilton, R.L., 1975. The Sar Cheshmeh porphyry copper deposit.Econ. Geol. 70, 568–576.

Westphal, M., Bazhenov, M.L., Lauer, J.P., Pechersky, D.M., Sibuet, J.C., 1986.Paleomagnetic implications on the evolution of Tethys belt from the Atlanticocean to the Pamirs since the Triassic. Tectonophysics 123, 37–82. http://dx.doi.org/10.1016/0040-1951(86)90193-9.

Wilkinson, J.J., 2001. Fluid inclusions in hydrothermal ore deposits. Lithos 55, 229–272, PII: S0024-4937_00.00047-5.

Yousefi, L., Karimpour, M.H., Hidarian Shahri, M.R., 2009. Geology, mineralogy, fluidinclusion microthermometry, and ground magnetic survey of magnetite–spcularite–copper–gold mineralization of Shaharak prospect area, Torbat-e-Hydarieh, Iran. Iranian J. Crystallogr. Mineral. 16, 505–516 (in Persian withEnglish abstract).

Zhai, D.G., Liu, J.J., Wang, J.P., Yao, M.J., Wu, S.H., Fu, C., Liu, Z.J., Wang, S.G., Li, Y.X.,2013. Fluid evolution of the Jiawula Ag–Pb–Zn deposit, Inner Mongolia:mineralogical, fluid inclusion, and stable isotopic evidence. Int. Geol. Rev. 55,204–224. http://dx.doi.org/10.1080/00206814.2012.692905.

Zhang, D.H., 1997. Some new advances in ore forming fluid geochemistry on boilingand mixing of fluids during the processes of hydrothermal deposits. Adv. EarthSci. 12, 546–550 (in Chinese with English abstract).

Zhu, Y.F., Zeng, Y.S., Jiang, N., 2001. Geochemistry of the ore-forming fluids in golddeposits from the Taihang mountains, northern China. Int. Geol. Rev. 43, 457–473. http://dx.doi.org/10.1080/00206810109465026.