U–Pb zircon geochronology, Sr–Nd geochemistry ...profdoc.um.ac.ir/articles/a/1049629.pdf · contains various granitoid rocks as dykes and stocks, which intruded into older pyroclastic

U–Pb zircon geochronology, Sr–Nd geochemistry, petrogenesis andtectonic setting of Mahoor granitoid rocks (Lut Block, Eastern Iran)

Roohollah Miri Beydokhti a, Mohammad Hassan Karimpour b,⇑, Seyed Ahmad Mazaheri b,José Francisco Santos c, Urs Klötzli d

aDepartment of Geology, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, IranbResearch Center for Ore Deposits of Eastern Iran, Ferdowsi University of Mashhad, Mashhad, IrancDepartment of Geosciences, Geobiotec Research Unit, University of Aveiro, 3810-193 Aveiro, PortugaldDepartment of Lithospheric Research, University of Vienna, Althanstrasse 14, 10-90 Vienna, Austria

a r t i c l e i n f o

Article history:Received 16 March 2015Received in revised form 23 July 2015Accepted 30 July 2015Available online 30 July 2015

Keywords:PetrogenesisU–Pb zircon geochronologySr and Nd isotope geochemistryMagmatic evolutionMahoor granitoid rocksLut BlockIran

a b s t r a c t

The Mahoor Cu–Zn-bearing porphyritic granitoid rocks belong to the Lut Block volcanic–plutonic belt(central Eastern Iran). These granitoid rocks occur mainly as dykes and stocks that intrude into Eocenevolcanics and pyroclastic rocks. Petrographically, all the studied intrusives display porphyritic textureswith mm-sized phenocrysts, most commonly of plagioclase and hornblende, embedded in afine-grained groundmass with variable amounts of plagioclase, hornblende, clinopyroxene, quartz andopaque minerals. Hydrothermal alteration affected these granitoid rocks, as revealed by the commonoccurrence of sericite, chlorite, titanite, epidote and calcite. Chemical classification criteria show thatthe intrusives may be named as gabbrodiorites, diorites, monzodiorites and tonalites. Major elementsgeochemistry reveals that all the studied lithologies are typically metaluminous (A/CNK 6 0.9).Magnetic susceptibility (1485 � 10�5 SI) together with mineralogical and geochemical features showsthat they belong to magnetite granitoid series (I-type). Trace element patterns normalized to chondriteand primitive mantle are very similar to each other and show enrichments in LREE relative to HREEand in LILE relative to HFSE, as well as negative anomalies of Ta, Nb and Ti. Eu/Eu⁄ ratios vary from0.88 (in the most mafic composition) to 0.65, showing that plagioclase played a role in magma differen-tiation. LA-MC-ICP-MS U–Pb zircon data from a diorite, yielded similar concordia ages of ca.31.88 ± 0.2 Ma (Error: 2r), which corresponds to the Oligocene period. These granitoid rocks have(87Sr/86Sr)i values vary between 0.7055 and 0.7063. In terms of isotopic compositions, while eNdi isbetween �0.6 and �2.5, suggesting that magmas underwent contamination through being exposed tothe continental crust. The whole set of geochemical data agree with the emplacement of the studiedintrusions in a magmatic belt above a subduction zone. Primitive magmas should have formed by meltingof mantle wedge peridotite, and during magma ascent to crustal levels, both magma differentiations tookplace by crystal fractionation and crustal contamination. Sulfide mineralizations (pyrite, chalcopyrite andsphalerite) related to these granitoid rocks is common and occurs as both disseminated and hydrother-mal veins, indicating a high mineralization potential for this area.

� 2015 Elsevier Ltd. All rights reserved.

1. Introduction

The Lut Block (LB) has a N–S elongated shape (Fig. 1) and it isbounded to the east by the Nehbandan Fault, to the north by theGreat Kavir Fault, and to the west by the Naybandan Fault. TheSouth Jazmourian Fault probably marks the southern limit of theBlock (Berberian and King, 1981). Sixty-five percent of the exposedrocks within the LB are volcanic and plutonic rocks (Karimpour

et al., 2011). The magmatic activity in the LB began in the middleJurassic (165–162 Ma) with the intrusion of Shah-Kuh batholithand reached its peak in the Tertiary (Esmaeily, 2005), especiallyin the middle Eocene (Arjmandzadeh and Santos, 2014). Volcanicand subvolcanic rocks of Tertiary age cover over half of LB withup to 2000 m thick and were formed due to subduction prior tothe collision of the Arabian and Asian plates (Camp and Griffis,1982; Tirrul et al., 1983; Berberian et al., 1999).

Eastern Iran, and particularly the LB, has a great potential fordifferent types of mineralization as a result of its past tectonicsetting in the form of a subduction zone, which led to extensive

http://dx.doi.org/10.1016/j.jseaes.2015.07.0281367-9120/� 2015 Elsevier Ltd. All rights reserved.

⇑ Corresponding author.E-mail address: [email protected] (M.H. Karimpour).

Journal of Asian Earth Sciences 111 (2015) 192–205

Contents lists available at ScienceDirect

Journal of Asian Earth Sciences

journal homepage: www.elsevier .com/locate / jseaes

magmatic activity. The episode of Middle Eocene to EarlyOligocene (30–39 Ma) was very important in terms of magma-tism and mineralization (Karimpour et al., 2011). Most of

magmatism and mineralization occurred in the east of Iran arerelated to Tertiary, (Arjmandzadeh and Santos, 2014), whileanother form of magmatism with which mineralization was

Fig. 1. Location of the Mahoor prospecting area in the East of Iran and the simplified geological sketch map of the Lut Block (modified from Arjmandzadeh et al. (2011)).

R.M. Beydokhti et al. / Journal of Asian Earth Sciences 111 (2015) 192–205 193

occurred was also identified in Cretaceous (e.g., Sn–Cu mineral-ization associated with the Cretaceous monzonitic rocks inKalateh Ahani) (Karimpour et al., 2011).

This work is focussed on the Mahoor prospecting area whichis located in eastern Iran, and in the central part of the LB.Based on geology, alteration, geochemistry, fluid inclusions,stable isotopes and mineralization studies, it shows characteris-tics similar to those of porphyry copper deposits (Fig. 1). The areacontains various granitoid rocks as dykes and stocks, whichintruded into older pyroclastic and volcanic units.Mineralization is related to intrusive rocks. However, due to thelack of systematical studies, the geochronology, petrogenesisand tectonic nature of these granitoid rocks have remainedunclear, so far.

In this paper, we represent new geochemical (both elementaland isotopic) and geochronological (U–Pb) data from those shallowintrusives, aiming at establishing tighter constraints on the petro-genetic processes and the geodynamic evolution of the LB.

2. Geological setting

The Mahoor prospecting area is located in the Tertiary metallo-genic volcano–plutonic belt of the LB and in the south part of1:250,000 scale of Dehsalm geological map (Griffis et al., 1991)(Fig. 1). According to Dehsalm geological map, a greater part ofthe study area is includes pre-Jurassic metamorphic rocks andJurassic sediments, intruded by Jurassic and Tertiary plutons,mainly of granitoid rocks, and covered with Tertiary mafic to felsiclava flows and pyroclastic materials.

The geological units that constitute the LB testify for a complextectonic history related to the evolution of the Sistan Ocean. Thisocean, probably, was opened by the Early Cretaceous as suggestedby radiolarian records (Babazadeh and de Wever, 2004). Recentlyobtained U–Pb zircon dates (Zarrinkoub et al., 2012), indicate thatthe generation of oceanic lithosphere has been in progress in theMiddle Cretaceous. The mechanism and timing of ocean closureremains poorly understood. For example, models involving

Fig. 2. Geological map of Mahoor prospecting area.

194 R.M. Beydokhti et al. / Journal of Asian Earth Sciences 111 (2015) 192–205

eastward subduction beneath the Afghan Block (Camp and Griffis,1982; Tirrul et al., 1983), western subduction beneath the LB(Zarrinkoub et al., 2012), two-sided subduction (Arjmandzadehet al., 2011) and eastward intraoceanic subduction (Saccani et al.,2010) all have been put forward. Ocean closure and thus theLut–Afghan collision were considered by some workers to have

occurred in the Middle Eocene (Camp and Griffis, 1982; Tirrulet al., 1983) or in the Late Cretaceous by some others (Angiboustet al., 2013; Zarrinkoub et al., 2012).

According to the studies, the lithology of the Mahoor prospect-ing area can be divided into three groups: 1 – Pre-Oligocenesequence of intermediate to felsic volcanic and pyroclastic rocks

Fig. 3. Field photographs and polarizing microscope images of the rocks of the Mahoor prospecting area rocks. (a) Dioritic dykes, (b) Diorite porphyry, (c) Monzodioriteporphyry, (d) Gabbrodiorite porphyry, (e) Tonalite porphyry, (f) Dioritic stock, (g) Diorite and (h) Andesite. (Abbreviations from Whitney and Evans (2010)).


Table 1Major (wt.%) and trace elements (ppm) data for the Mahoor granitoid and volcanic rocks.

Sample no. M1 M2 M3 M4 M5 M6 M7 M8 M9Rock type D D Gd Ba Ba Tph An An Tph

Major elements (%)SiO2 57.53 57.85 56.34 55.98 56.18 63.75 56.95 57.18 61.93TiO2 0.82 0.84 0.88 0.93 0.89 0.69 0.75 0.77 0.7Al2O3 15.65 15.54 15.61 16.37 16.37 14.6 16.14 16 14.44FeOt 7.41 7.4 7.99 8.33 7.8 5.57 7.56 7.47 6.29MnO 0.15 0.15 0.17 0.16 0.19 0.11 0.18 0.15 0.12MgO 4.28 4.15 4.59 3.69 4.36 3.16 5.35 4.88 3.04CaO 6.13 6.35 7.5 7.82 7.31 3.21 6.08 6.36 4.26Na2O 3.42 3.18 2.9 3.38 3.01 3.46 2.89 2.86 3.68K2O 2.44 2.47 2.24 2.44 2.6 3.75 1.41 1.67 3.16P2O5 0.3 0.32 0.3 0.24 0.24 0.19 0.28 0.27 0.24LOI 1.64 1.52 1.27 0.41 0.8 1.3 2.17 2.15 1.92Na2O/K2O 1.4 1.29 1.29 1.39 1.16 0.92 2.05 1.71 1.16Total 99.77 99.77 99.79 99.75 99.75 99.79 99.76 99.76 99.78

Trace elements (ppm)Ba – 387 347 438 – 460 – 457 465Hf – 3.5 2.8 3.8 – 6 – 3.3 5Ta – 0.4 0.4 0.4 – 0.9 – 0.5 0.8Cs – 1.7 1.6 4.7 – 3.6 – 8.2 1.6Co – 15.8 19.4 21.7 – 11.7 – 16.9 11.5Nb – 7.6 6.9 6.7 – 10.9 – 8.8 9.3Ce – 41.1 37 38 – 59.1 – 48.4 49.6Sr – 397.2 454 428.4 – 326.6 – 581 412.3Rb – 63.1 51 76.3 – 154.3 – 74.4 82.3Zr – 133.4 121.5 115.8 – 220.1 – 140.7 171.4La – 20.1 17.3 18.2 – 29 – 25.4 24.9Pr – 4.89 4.61 4.56 – 6.5 – 5.67 5.84Nd – 20.1 17.3 19.4 – 23.6 – 20.4 22.8Sm – 4.13 4.35 4.22 – 5.12 – 4.39 4.63Eu – 1.13 1.11 1.17 – 1.03 – 1.08 1.11Gd – 4.35 4.51 4.39 – 4.55 – 4.06 4.67Tb – 0.64 0.61 0.66 – 0.64 – 0.61 0.66Dy – 3.6 3.94 4.05 – 4.65 – 3.66 4.39Ho – 0.83 0.72 0.83 – 0.84 – 0.74 0.84Er – 2.54 2.24 2.41 – 2.6 – 2.16 2.42Tm – 0.34 0.32 0.36 – 0.34 – 0.31 0.38Yb – 2.04 2.2 2.37 – 2.58 – 2.04 2.49Lu – 0.33 0.32 0.34 – 0.37 – 0.28 0.38Y – 23.5 23.5 22.5 – 24.1 – 20.7 26.9Co – 15.8 19.4 21.7 – 11.7 – 16.9 11.5Th – 4.9 5.4 5.2 – 14.3 – 7 9.4U – 1 1.2 1.3 – 3.3 – 1.6 1.9Eu/Eu⁄ – 0.82 0.77 0.83 – 0.65 – 0.78 0.73(La/Yb)N – 6.64 5.3 5.18 – 7.58 – 8.39 6.74(Yb)N – 9.8 10.5 11.3 – 12.3 – 9.8 11.9

Sample no. M10 M13 M14 M15 M16 M18 M19 M21Rock type Tph Dph Mzdph Tph Gd Dph Tph Gdph

Major elements (%)SiO2 63.88 59.8 59.18 63.44 56.37 60.28 64.34 51.65TiO2 0.63 0.74 0.69 0.6 0.86 0.72 0.64 1.21Al2O3 14.46 14.92 14.85 14.77 15.59 14.6 14.91 15.45FeOt 5.39 6.49 7.02 5.48 7.81 6.62 3.76 9.52MnO 0.11 0.11 0.13 0.11 0.16 0.12 0.05 0.2MgO 2.62 4.57 4.64 2.66 4.98 4.28 2.64 4.8CaO 3.47 4.18 4.11 3.63 7.42 4.67 4.19 6.99Na2O 3.74 3.35 3.64 3.14 2.75 2.93 4.92 2.78K2O 3.39 3.2 3.18 3.75 2.22 3.52 3.38 2.42P2O5 0.2 0.25 0.28 0.27 0.31 0.22 0.24 0.49LOI 1.52 2.16 2.06 1.87 1.32 1.83 0.61 4.29Na2O/K2O 1.10 1.05 1.14 0.84 1.24 0.83 1.46 1.15Total 99.41 99.77 99.78 99.72 99.79 99.79 99.68 99.8

Trace elements (ppm)Ba 496 387 430 520 – 442 483 310Hf 4.9 4.5 4.2 4.4 – 5.4 5.5 3.3Ta 0.8 0.7 0.9 0.7 – 0.6 0.8 0.5Cs 2.2 3.7 5.3 2.6 – 5.2 1.8 5.4Co 9.5 15.7 14.4 10.2 – 13.6 6.1 17.9Nb 9.9 9.8 9.8 8.4 – 9.7 10.3 8.8Ce 52.6 50.5 55.4 50.8 – 49 51 48.6Sr 368 428.5 388.4 422.7 – 378 260.9 434.8


including andesite, dacite, rhyolite, tuff and lithic tuff. 2 – EarlyOligocene intermediate plutonic rocks that are intruded into vol-canic units and are mainly diorite, gabbrodiorite, monzodioriteand monzonite. 3 – Quaternary sediments including old and youngalluvials (Fig. 2).

3. Analytical methods

3.1. Major and trace element analysis

According to petrographic studies seventeen samples of unal-tered rocks representing the main lithologies of Mahoor prospect-ing area (13 intrusive rocks and 4 volcanic rocks) were selected formajor and trace element chemical analysis. Major and trace ele-ments were determined by wave-length-dispersive X-ray fluores-cence (XRF) spectrometry using fused disks and the Philips PW1410 XRF spectrometer at Kansaran Binalood Company,Mashhad, Iran. Thirteen of these samples were analyzed for traceelements using inductively coupled plasma-mass spectrometry(ICP-MS), following a lithium metaborate/tetraborate fusion andnitric acid total digestion, in the Acme Laboratories, Vancouver(Canada).

3.2. Magnetic susceptibility

Magnetic susceptibility of Mahoor intrusive rocks was mea-sured with the HZ Instruments SM-30 device having an accuracyof 1 � 10�7 SI at Ferdowsi University of Mashhad, Mashhad, Iran.

3.3. Rb–Sr and Sm–Nd isotopic analysis

Sr and Nd isotopic compositions were determined for ninewhole-rock samples of the Mahoor granitoid rocks and volcanicrocks at the Laboratory of Isotope Geology, University of Aveiro,Portugal. The selected powdered samples were dissolved withHF/HNO3 solution in Teflon Parr acid digestion bombs at 200 �Cfor 3 days. After evaporation of the final solution, the samples weredissolved with HCl (6.2 N) also in acid digestion bombs, and driedagain. The elements to analyze were purified using conventionalion chromatography technique in two stages: (a) separation of Sr

and REE elements in ion exchange column with AG8 50 WBio-Rad cation exchange resin; (b) purification of Nd from otherlanthanides elements in columns with Ln Resin (ElChromTechnologies) cation exchange resin. All reagents used in thepreparation of the samples were sub-boiling distilled, and thewater was produced by a Milli-Q Element (Millipore) apparatus.Sr was loaded on a single Ta filament with H3PO4, whereas Ndwas loaded on a Ta outer side filament with HCl in a triple filamentarrangement. 87Sr/86Sr and 143Nd/144Nd isotopic ratios were deter-mined using a Multi-Collector Thermal Ionization MassSpectrometer (TIMS) VG Sector 54. Data were acquired in dynamicmode with peak measurement at 1–2 V for 88Sr and 0.5–1.0 V for144Nd. Sr and Nd isotopic ratios were corrected for mass fractiona-tion relative to 88Sr/86Sr = 0.1194 and 146Nd/144Nd = 0.7219. Duringthis study, the SRM-987 standard gave an average value of87Sr/86Sr = 0.710266 ± 14 (conf. lim 95%, N = 13) and143Nd/144Nd = 0.5121019 ± 75 (conf. lim 95%, N = 12) to JNdi-1standard.

3.4. Zircon U–Pb dating

Pyroxene hornblende diorite sample (Fig. 2) was collected forLA-ICP-MC–MS zircon U–Pb analyses. The LA-ICP-MC–MS analyti-cal work was performed at the Laboratory of Geochronology,Center for Earth Sciences, University of Vienna. They were sepa-rated by heavy liquid and magnetic separation, followed by handpicking under a binocular microscope. More than 60 zircon grainswere found. The sizes of the zircons are 100–200 lm in length and30–100 lm in width. The handpicked inclusion free zircon frac-tions were mounted in epoxy and then ground and polished priorto CL imaging and LA-ICP-MC–MS analysis.

CL imaging was performed with a TESCAN CL DECTOR SEMwith15 kV acceleration voltages at GOELOGICAL SURVEY OF VIENNA,AUSTRIA. Cathodoluminescence (CL) images were obtained beforeLA-ICP-MC–MS dating of the zircon crystals in order to distinguishbetween different zircon domains. The imaging was repeated afterthe LA-ICP-MC–MS measurements to confirm the exact location ofthe spots/line paths.

Zircon 206Pb/238U and 207Pb/206Pb ages were determined using a193 nm solid state Nd-YAG laser (NewWave UP193-SS) coupled to

Table 1 (continued)

Sample no. M10 M13 M14 M15 M16 M18 M19 M21Rock type Tph Dph Mzdph Tph Gd Dph Tph Gdph

Rb 107.7 116.4 124.9 106.6 – 128.9 76.1 63.3Zr 181.1 178 175.2 159.2 – 176.3 185.5 125.8La 25.9 24.9 25.4 25.2 – 24.9 26 22.6Pr 6 5.59 5.82 5.63 – 5.77 5.87 6.04Nd 22 22.1 21.4 23.1 – 22.1 23 24.3Sm 4.53 4.51 4.14 4.34 – 4.47 4.41 5.48Eu 1.19 0.97 1 1.06 – 1.13 1.05 1.6Gd 4.46 4.21 4.17 4.3 – 4.25 4.44 5.66Tb 0.66 0.58 0.61 0.59 – 0.6 0.72 0.82Dy 4.28 4.37 4.38 3.74 – 4 4.4 5.42Ho 0.8 0.77 0.67 0.75 – 0.74 0.8 1.12Er 2.64 2.24 2.02 2.01 – 2.19 2.53 2.94Tm 0.37 0.34 0.33 0.32 – 0.33 0.39 0.44Yb 2.83 2.07 2.19 2.18 – 2.09 2.7 3.13Lu 0.36 0.37 0.35 0.33 – 0.34 0.39 0.45Y 21 21.3 22.6 21.4 – 22.9 25.9 26.7Co 9.5 15.7 14.4 10.2 – 13.6 6.1 17.9Th 9.8 10.3 10.6 8.8 – 10.7 11.5 5.8U 2.3 2.6 2.5 2.1 – 2.8 2.9 1.1Eu/Eu⁄ 0.81 0.68 0.74 0.75 – 0.79 0.73 0.88(La/Yb)N 6.17 8.11 7.82 7.79 – 8.03 6.49 4.87(Yb)N 13.5 9.9 10.5 10.4 – 10 12.9 15

(D) Diorite, (Gd) Gabbrodiorite, (Dph) Diorite porphyry, (Tph) Tonalite porphyry, (Gdph) Gabbrodiorite porphyry, (Mzdph) Monzodiorite porphyry, (Ba) Basaltic andesite, and(An) Andesite.


a multi-collector ICP-MS (NuInstruments HR) at the University ofVienna. Ablation in a He atmosphere was either spot or raster wiseaccording to the CL zonation pattern of the zircons. Spot analyseswere 15–25 lm in diameter whereas line widths for rastering were10–15 lm with a rastering speed of 5 lm/s. Energy densities were5–8 J/cm2 with a repetition rate of 10 Hz. The He carrier gas wasmixed with the Ar carrier gas flow prior to the plasma torch.Ablation duration was 60–120 s with a 30 s gas and Hg blank countrate measurement preceding ablation. Ablation count rates werecorrected accordingly offline. Remaining counts on mass 204 wereinterpreted as representing 204Pb. Static mass spectrometer analy-sis was as follows: 238U in a Faraday detector, 207Pb, 206Pb, and 204(Pb + Hg) were in ion counter detectors. 208Pb was not analyzed. Anintegration time of 1 s was used for all measurements. The ioncounter Faraday and inter-ion counter gain factors were deter-mined before the analytical session using standard zircons 91500(Wiedenbeck et al., 1995) and Plesovice (Slama et al., 2006).Sensitivity for 206Pb on standard zircon 91500 was c. 300000cpsper ppm Pb. For 238U the corresponding value was c. 350000.

4. Petrographical characteristics of intrusive rocks

The present study involves detailed field work and petrographicstudy of more than 100 samples of intrusive rocks from theMahoor prospecting area. The samples used in this study were col-lected from the outcrops.

Plutonic and porphyry complexes in Mahoor prospecting areaare represented by a series of rocks similar in composition. About5 intrusive units based on type and abundance of phenocrysts,matrix and mafic minerals are identified, based on type and abun-dance of phenocrysts in the study area (Fig. 2). All these rocks aretexturaly porphyritic, and have medium to fine grained phe-nocrysts of plagioclase, hornblende, pyroxene and quartz in a finegrained matrix. Accessory minerals include apatite, titanite andzircon. Opaque minerals are pyrite and magnetite.

4.1. Diorite porphyry

The diorite porphyry units mainly occur as dykes and stocks(Fig. 3a) and have porphyritic texture (Fig. 3b) with 45–50% of phe-nocrysts. The phenocrysts are plagioclase (25–35%), hornblende(2–7%), pyroxene (2–3%) and quartz (3–5%). The matrix has amicrocrystalline texture with a crystal size <0.05 mm, which

comprises plagioclase, K-feldspar, quartz and accessory mineralsof titanite, apatite, pyrite, magnetite, and zircon.

4.2. Monzodiorite porphyry

The monzodiorite porphyry has porphyritic texture (Fig. 3c)with 50% of phenocrysts. The phenocrysts are plagioclase (25–30%), K-feldspar (7–10%), hornblende (5–6%) and quartz (4–5%).The matrix has a microcrystalline texture with a crystal size of<0.05 mm, which comprises plagioclase, K-feldspar, quartz andaccessory minerals i.e. apatite, magnetite, and zircon.

4.3. Gabbrodiorite porphyry

The gabbrodiorite porphyry also has porphyritic texture with65% of phenocrysts (Fig. 3d). The phenocrysts are plagioclase(42–45%), hornblende (8–10%) and pyroxene (5%). The matrix ismicrocrystalline with a crystal size of <0.1 mm, which comprisesplagioclase (10–15%), quartz (2–3%), K-feldspar (2%), and accessoryminerals (1%) of magnetite, titanite, apatite, zircon, and pyrite.

4.4. Tonalite porphyry

The tonalite has small outcrops in center of the study area. Ithas porphyritic texture (Fig. 3e) with 35% of phenocrysts. The phe-nocrysts are plagioclase (25–30%) and hornblende (2–3%). Thematrix has a microcrystalline texture with a crystal size of<0.05 mm, which comprises plagioclase, quartz and accessory min-erals of apatite, magnetite, and zircon.

4.5. Diorite

The diorite unit crops out as stock (Fig. 3f) and has granular tex-ture (Fig. 3g). The diorite is composed of major minerals of plagio-clase (55–60%), hornblende (8–10%), K-feldspar (7–9%), pyroxene(5–6%) and quartz (3–4%). The accessory minerals of diorite areapatite, magnetite, pyrite and zircon.

4.6. Andesite porphyry

The andesite is dark and displays a porphyritic texture and mas-sive structure (Fig. 3h), with phenocrysts (�40% of the rock mass)

Fig. 4. (a) R1 vs. R2 and (b) SiO2 vs. K2O diagrams for Mahoor magmatic rocks. The field boundaries in (A) are from Dela Roche et al. (1980) and in (B) are from Peccerillo andTaylor (1976).


of plagioclase and pyroxene. The groundmass is dominated by pla-gioclase and cryptocrystalline material.

5. Analytical results

5.1. Major and trace elements

Whole-rock major and trace element data are listed in Table 1.

5.1.1. Intrusive rocksGranitoid rocks from the Mahoor area have a relatively wide

range of SiO2 (52–64 wt.%). They have relatively high Na2O (2.7–4.9 wt.%) and K2O (2.2–3.8 wt.%), with high total alkali concentra-tions (K2O + Na2O = 4.5–8.3 wt.%) and K2O/Na2O ratios (0.69–1.2),high contents of CaO (3.2–7.5 wt.%) and FeOt (3.8–9.5 wt.%), MgO(2.6–4.9 wt.%), TiO2 (0.6–1.2 wt.%), MnO (0.05–0.2 wt.%) andP2O5(0.19–0.49 wt.%). Al2O3 contents range from 14.4 to15.6 wt.%. All granitoid rock samples plot in the fields of gabbrodi-orite, diorite, monzodiorite and tonalite of the Dela Roche et al.(1980) diagram (Fig. 4a), and fall into the high-K calc-alkaline ser-ies field in the SiO2 vs. K2O diagram (Peccerillo and Taylor, 1976)(Fig. 4b). All calculated A/CNK values (molar

Al2O3/(CaO + Na2O + K2O)) are concentrated in the range from 0.7to 0.95, indicating that these rocks are metaluminous (Fig. 5).

5.1.2. Volcanic rocksThe analyzed samples show uniformly changed major element

compositions, with SiO2 contents of 56–57.2 wt.%. These samplesshow K2O contents of 1.4–2.6 wt.%, and plot into the high-Kcalc-alkaline series on the K2O–SiO2 diagram (Peccerillo andTaylor, 1976) (Fig. 4b). Similarly, these samples show Al2O3 con-tents of 16–16.4 wt.%, and plot in the metaluminous range on theA/CNK–A/NK diagram (Fig. 5), and display high MgO (3.7%–5.4%)(Table 1).

The Mahoor granitoid rocks and volcanics have a large variationof trace element content (Table 1). In primitive mantle-normalizedspider gram (Fig. 6), all samples exhibit similar trace element pat-terns, with significant negative anomalies of high field strengthelements (HFSE, e.g., Nb, Ti and Zr) and there are positive anoma-lies of large ion lithophile elements (LILE, e.g., Rb, Th, Ba and U).

The Mahoor granitoid rocks and volcanics have similarchondrite-normalized REE patterns (Fig. 7). Parallelchondrite-normalized REE patterns show that Mahoor intrusivesare cogenetic. The

PREE ranges from 96.5 to 140.9 ppm, with

LREE/HREE = 5.4–7.9 with weak to moderate enrichment of lightREE [(La/Yb)N = 4.87–8.39] and a relatively flat heavy REE profile[(Gd/Yb)N = 1.33–1.72]. The whole rocks have weak negative Euanomalies, with Eu/Eu⁄ of 0.65 to 0.88.

5.2. Zircon U–Pb results

Zircon U–Pb dating appears to be the best method for determin-ing the ages of the magmatic rocks in the region because thehydrothermal alteration influenced rocks and it is difficult to useother methods. The diorite (M2) sample from the Mahoorprospecting area was selected for zircon U–Pb isotope dating.Twenty zircons of high transparency and free of visible inclusionswere chosen for LA-ICP-MS U–Pb isotope analysis. U–Pb data arelisted in Table 2.

CL images of zircons from the studied rocks show euhedral–subhedral shapes and typical oscillatory growth zoning withoutdistinctively older cores or younger overgrowths (Fig. 8),

Suggesting their igneous origin (Hanchar and Hoskin, 2003).Fig. 9 is a concordia plot for the data and the concordia age is31.88 ± 0.2 Ma (95% confidence, MSWD = 1.5, n = 6).

Fig. 5. Al2O3/Na2O + K2O (molar) vs. Al2O3/(CaO + K2O + Na2O) (molar) (Maniar andPiccoli, 1989) and the field boundaries between S-type and I-type granite are fromChappell and White (1992).

Fig. 6. Primitive-mantle-normalized trace element patterns for the granitoid andvolcanic rocks of the Mahoor district. Normalizing values are from Sun andMcDonough (1989).

Fig. 7. Chondrite-normalized REE patterns for the granitoid and volcanic rocks ofthe Mahoor district. Normalizing values are from Boynton (1985).


5.3. Sr–Nd isotopic compositions

The elements that have stable radiogenic isotopes like Sr and Ndare useful for studies of the origin of igneous rocks because theirisotope compositions, unlike the concentrations of major and trace

elements, are not fractionated by partial melting and by the subse-quent crystallization of minerals from cooling magma (Faure andMensing, 2005). The results of analysis for Sr–Nd isotopes andNd model ages (TDM), are presented in Table 3. The Mahoor gran-itoid rocks have meso-neoproterozoic Nd model ages(TDM = 1150–810 Ma), whereas the andesits have Nd model ages,ranging from 880 Ma to 1110 Ma.

Initial Sr isotopic (87Sr/86Sr)i values and Nd isotopic parametereNd(t) values are calculated at t = 31.9 Ma for plutonic and volcanicrocks. The Mahoor granitoid rocks display significant variability ininitial (87Sr/86Sr)i ratios, ranging from 0.7056 to 0.7063, and nega-tive eNd(t) values of �0.6 to �2.5. Mahoor volcanic display signif-icant variability in initial (87Sr/86Sr)i ratios, 0.7058 for basalticandesite and 0.7065 for andesite and have Nd isotopic composi-tions (eNd(t) = �3.4 for the basaltic andesite and �0.6 for the ande-site respectively.

5.4. Magnetic susceptibility

Granitic rocks were classified into the magnetite series and theilmenite series by Ishihara (1977). Showing a magnetic susceptibil-ity value more than 50.0 � 10–5 SI units), granites are classified asmagnetite series (Ishihara, 1981). Measurement of magnetic sus-ceptibility for the rock types are shown in Table 4. The Mahoorgranitoid rocks plot in the field of magnetic series on the Rb/Srvs. Magnetic susceptibility diagram (Fig. 10). Their magnetic sus-ceptibility is mostly more than 480 � 10�5 SI.

6. Discussion

In the plots of 10,000 Ga/Al vs. (K2O + Na2O) and(K2O + Na2O)/CaO (Whalen et al., 1987) both samples fall in thefields of I- and S-type granites (Fig. 11). Additionally, in contrastto the highly siliceous S-type granites that are typically stronglyperaluminous with A/CNK value much higher than 1.1 (Chappelland White, 1992, 2001; Clemens et al., 2011), these rocks haveA/CNK values below 1.0 (Fig. 5). Further-more, P2O5 contents rangefrom 0.2 to 0.49 (Table 1) that are negatively correlated withSiO2(not show here) which is regarded as an important criteria for dis-tinguishing I-type granites from S-type granites. The apatitereaches saturation status in metaluminous and mildly peralumi-nous magmas (A/CNK lower than 1.1), but is highly soluble instrongly peraluminous melts (Li et al., 2007). Thus, the Mahoorgranitoid rocks are typical I-type, rather than A- or S-type intru-sions. In agreement with the metaluminous and I-type characteris-tics of Mahoor granitoid rocks, according to Pearce et al. (1984),these rocks plot on the fields of the volcanic arc granites(Fig. 12). According to Schandl and Gorton (2002) diagrams, theserocks were formed in active continental margins (Fig. 13). In Sr/Yvs. Y and (Yb)N vs. (La/Yb)N discrimination diagrams (Martin,1999; Defant and Drummond, 1990), all samples are plotted inthe field of classic island arc (Fig. 14a and b).

Table 2Zircon U–Pb isotopic data for the Mahoor granitoid rocks (zircons from sample M2).

File name Final blank corrected intensities Final mass bias and common Pb corrected ratios

204Pba 206Pbb 207Pbb 238Ub 207Pb/206Pb 2RSE (%) 207Pb/235U 2RSE (%) 206Pb/238U 2RSE (%) RHO 206Pb/238UAge(Ma)Error2r

M2-Zr_a2a 2.95 0.69 0.086 140 0.0987 2.6 0.0747 1.8 0.0055 1.75 0.87 35.3M2-Zr-a2b N.D. 0.74 0.048 165 0.0476 1.19 0.0327 4.6 0.0050 4.53 0.61 32.0M2-Zr-a3 N.D. 0.20 0.013 43 0.0465 0.91 0.0321 2.64 0.0050 2.57 0.44 32.2M2-Zr-a4 4.91 0.38 0.018 112 0.0469 2.82 0.0322 5.49 0.0050 5.49 0.32 32.1M2-Zr-b1 4.39 0.39 0.018 120 0.047 7.33 0.0322 3.27 0.0050 3.19 0.34 32.0M2-Zr-a1 3.52 0.31 0.014 98 0.0464 2.27 0.0317 0.71 0.0050 0.67 0.22 31.8

a Explanations: final blank corrected intensities in lV.b Final blank corrected intensities in mV; 2RSE 2-sigma relative standard error (in %); Rho the error-correlation between the 206Pb/238U and 207Pb/235U ratios.

Fig. 8. Cathodoluminescence images of representative zircon grains from samplesM2. The red line and circles indicate the analyzed spots. (For interpretation of thereferences to color in this figure legend, the reader is referred to the web version ofthis article.)

Fig. 9. U–Pb isotopic age distributions of analyzed zircons from samples M2.


Primitive mantle-normalized trace element spider diagrams(Sun and McDonough, 1989) display strong enrichment in largeion lithophile elements (LILE), such as Rb, Ba and Cs, and otherincompatible elements that behave very similarly to LILE (Thand U) (Fig. 6). The most characteristic high field strength ele-ments (HFSE) – e.g. Nb, Zr, Y, Ti and HREE – compared to LILE,have clearly lower normalized values; Nb, Ti, while define deepnegative anomalies (Fig. 6).

These features are typical of the subduction-related magmas,namely in the calc-alkaline volcanic arcs of continental activemargins (e.g.: Gill, 1981; Pearce, 1983; Wilson, 1989; Walkeret al., 2001). Their high Sr and low Nb, Ta and Ti contents arethought to be due to the absence of plagioclase and presence ofFe–Ti oxides in the residue in the source area of the parental mag-mas (Martin, 1999); Nb and Ta contents may be a result of previ-ous depletion events in the mantle source rocks (Woodhead et al.,1993; Gust et al., 1997). Phosphorous also show negative anoma-lies in the studied samples, which may be related to apatite frac-tionation. Although, as already was described, LILE are enrichedrelative to HFSE, Rb and Ba display low normalized values thatmight be explained by the involvement of a sediment componentfrom the subducted slab during the compositional changesunderwent by the peridotites of the source area (Borg et al.,1997; Leat et al., 2003). Rare-earth element patterns inchondrite-normalized plots display high degrees of REE fraction-ation (Fig. 7), with low to meadium LREE enrichment(4.9 6 LaN/YbN 6 8.4). These ratios are less than those in the mag-mas (Martin, 1987) whose source contain garnet; thereforespinel/amphibolite may be present in residual. All studied rockshave Eu/Eu⁄ ratios from 0.65 to 0.88. Normally, a negative Euanomaly develops with magma differentiation due to fractionalcrystallization of early plagioclase (Henderson, 1984).Ta

ble3

Rb–S

ran

dSm

–Ndisotop

icda

tafrom

elev

enwho

le-roc

ksamples

oftheMah

oorgran

itoidan

dvo

lcan

icrock

s.

Sample

Sr (ppm

)Rb

(ppm

)

87Rb/

86Sr

87Rb/

86Sr

Error

(2s)

87Sr/8

6Sr

87Sr/8

6Sr

Error

(2s)

(87Sr/8

6Sr)i

Nd

(ppm

)Sm (ppm

)

147Sm

/144Nd

147Sm

/144NdError

(2s)

143Nd/

144Nd

143Nd/

144NdError

(2s)

eNdi

TDM

(Ma)

M6

326.6

154.3

1.36

70.03

90.70

7028

0.00

0024

0.70

6323

.65.12

0.13

10.00

70.51

2495

0.00

0016

�2.5

1039

M9

412.3

82.3

0.57

70.01

60.70

6171

0.00

0017

0.70

5822

.84.63

0.12

30.00

70.51

2588

0.00

0023

�0.6

809

M15

422.7

106.6

0.73

00.02

10.70

6256

0.00

0027

0.70

5823

.14.34

0.11

40.00

60.51

2519

0.00

0013

�1.9

838

M18

378.0

128.9

0.98

70.02

80.70

6776

0.00

0023

0.70

6222

.14.47

0.12

20.00

70.51

2492

0.00

0013

�2.5

951

M3

454.0

51.0

0.32

50.00

90.70

5716

0.00

0025

0.70

5617

.34.35

0.15

20.00

80.51

2585

0.00

0015

�0.8

1153

M21

434.8

63.3

0.42

10.01

20.70

5901

0.00

0018

0.70

5724

.35.48

0.13

60.00

70.51

2588

0.00

0017

�0.7

938

M14

388.4

124.9

0.93

00.02

60.70

6734

0.00

0020

0.70

6221

.44.14

0.11

70.00

60.51

2502

0.00

0016

�2.2

888

M19

260.9

76.1

0.84

40.02

40.70

6652

0.00

0023

0.70

6223

.04.41

0.11

60.00

60.51

2513

0.00

0015

�2.0

864

M13

428.5

116.4

0.78

60.02

20.70

6727

0.00

0020

0.70

6322

.14.51

0.12

30.00

70.51

2510

0.00

0017

�2.1

935

M4

428.4

76.3

0.51

50.01

50.70

5778

0.00

0020

0.70

5519

.44.22

0.13

20.00

70.51

2592

0.00

0017

�0.6

880

M8

581.0

44.8

0.37

00.01

00.70

6543

0.00

0017

0.70

6420

.44.39

0.13

00.00

70.51

2448

0.00

0018

�3.4

1105

Note:

87Rbde

cayk=1.42

�10

�11ye

ar�1;147Sm

decayk=6.54

�10

�12ye

ar�1;Th

e143Nd/

144Ndan

d147Sm

/144Ndratios

ofch

ondritean

dde

pleted

man

tleat

presen

tda

yare0.51

2638

and0.19

67,0

.513

15an

d0.21

37,respe

ctively

(Jacob

senan

dW

asserburg,1

980).

Table 4Magnetic susceptibility of the Mahoor granitoid rocks.

Sample Susceptibility (�10�5 SI) Lithology

M2 1769 DioriteM3 1977 GabbrodioriteM11 2208 Diorite porphyryM12 2788 Diorite porphyryM15 2241 Tonalite porphyryM10 480 Tonalite porphyryM6 1350 Tonalite porphyryM17 937 Monzodiorite porphyryM14 702 Monzodiorite porphyryM9 556 Tonalite porphyryM20 1577 Diorite porphyryM22 1244 Diorite porphyry

Fig. 10. A plot of Rb/Sr vs. magnetic susceptibility (Karimpour et al., 2011).


Fig. 11. Granite discrimination diagrams for the Mahoor granitoid rocks (Whalen et al., 1987).

Fig. 12. Tectono-magmatic discrimination diagrams for the Mahoor granitoid rocks (Pearce et al., 1984). WPG: within-plate granitoids; VAG: volcanic arc granitoids; ORG:ocean ridge granitoids; syn-COLG: syncollisional granitoids.

Fig. 13. Tectonomagmatic discrimination diagrams for the Mahoor granitoid rocks (Schandl and Gorton, 2002).


Negative eNd(t) values represent the features of the crustalmelt, and the positive eNd(t) isotopic ratios are consistent withmantle array (Kemp et al., 2007; Li et al., 2009; Yang et al.,2007). Based on the eNd(t) – (87Sr/86Sr)i isotopic plot (Fig. 15),the Mahoor granitoid rocks display a trend toward the upper con-tinental crust, implying that the crust contamination played a rolein magma evolution (Kemp et al., 2007; Li et al., 2009) (Fig. 15).Such contamination is widely recognized as a consequence of heattransfer from hot magmas to cool crust (DePaolo, 1981).

The eNd(t) and (87Sr/86Sr)i vs. SiO2 diagrams of the Mahoor sam-ples are used to examine whether crustal assimilation occurred ornot (Xu et al., 2014) (Fig. 16). The Sr and Nd isotope data show cor-relative variation with the SiO2 contents. We can see variationtrends of eNd(t) and (87Sr/86Sr)i that are both in agreement withcrustal assimilation. Hence, we suggest that crustal assimilationplay an important role during the magmatic evolution of theMahoor granitoid rocks.

The eNd(t) and (87Sr/86Sr)i values in Mahoor granitoid rocks aredifferent from the eNd(t) values of other intrusions within the cen-ter part of the LB (e.g., Arjmandzadeh et al., 2011; Arjmandzadeh

and Santos, 2014) (Fig. 15), indicating that these rocks originatedfrom a different source or Mahoor granitoid rocks had more con-tamination with continental crust when they ascend. We proposea model to illustrate the genesis and geodynamic setting of theOligocene Mahoor granitoid rocks (Fig. 17).

It has been shown that elemental ratios, such as Nb/Ta ratioscan be very useful in fingerprinting source regions (Eby et al.,1998). Mahoor intrusions have Nb/Ta ratios from 11.6 to 19, withan average value of 14.6, which is slightly higher than the rangesof lower crust Nb/Ta = 8.3 (Sun and McDonough, 1989). It is sug-gested that Mahoor granitoid rocks did not only derive fromremelting of the lower crust.

Fig. 14. (a) Plot of Mahoor granitoid rocks on Y vs. Sr/Y diagram. Fields after Defant and Drummond (1990). (b) Plot of Mahoor intrusives on YbN vs. (La/Yb)N diagram. Fieldsafter Li et al. (2009).

Fig. 15. eNdi – (87Sr/86Sr)i diagram for the Mahoor rocks. Data for Dehsalmgranitoid rocks from Arjmandzadeh and Santos (2014) and for Chah-Shaljamigranitoid rocks from Arjmandzadeh et al. (2011).

Fig. 16. (87Sr/86Sr)i ratios and eNdi values vs. SiO2 diagrams (Xu et al., 2014) for theMahoor samples.


Dating results of Mahoor area are supported by the widespreadoccurrence of concurrent magmatism and mineralization on othersides of the LB. For example, the age of Kooh-Shah granitoid rocks,based on zircon U–Pb age dating in 140 km north of Mahoor area,is 39.7 ± 0.7 Ma (Abdi and karimpour, 2013). The age of quartzmonzonite from the Dehsalm Cu–Mo-bearing porphyritic granitoidrocks in 40 km south-east of Mahoor area is 33.3 ± 1 Ma(Arjmandzadeh and Santos, 2014). Similarly, the Rb–Sr dating ofquartz monzonite from the Chah Shaljami Cu–Mo deposit (42 kmnorth-east of Mahoor area) gave ages of 33.5 ± 1 Ma(Arjmandzadeh et al., 2011).

7. Conclusions

Major element geochemistry reveals that all the studied litholo-gies are typically metaluminous (A/CNK 6 0.94) and, in addition,they constitute a suite which belongs to the high-K calc-alkalineseries. Magnetite susceptibility (>480 � 10�5 SI) together withmineralogical and geochemical features shows that they belongto magnetite granitoid series (I-type). In primitivemantle-normalized trace element spider diagrams, the analyzedsamples display strong enrichment in LILE compared to HFSE(15.5 6 RbN/YN 6 45.9), while being accompanied by negativeanomalies of Nb, Ta and Ti. REE chondrite-normalized plots showslight to moderate LREE enrichment (4.9 6 LaN/LuN 6 8.4) and neg-ative Eu anomalies (Eu/Eu⁄ ratios vary from 0.65 to 0.88). Mahoorgranitoid rocks display trace element features typical of the mag-matism related to a subduction zone. The Zircon U–PbGeochronology show an intrusion age of 31.88 ± 0.2 Ma. Isotopegeochemistry shows that the studied rocks are co-genetic andshould be related to each other mainly by magmatic differentiationprocesses, such as fractional crystallization. Therefore, the highK2O contents are expected to result from assimilation of crustalmaterials rather than from mantle source geochemistry. The par-ental magmas, probably, were derived from partial melting ofmetasomatized peridotite in a supra-subduction mantle wedge;during the melting event, phlogopite breakdown should have con-tributed to some of the most important geochemical fingerprints ofthe suite; garnet and amphibole possibly remained as residualphases in the source. This study provides more evidence for sub-duction beneath the LB during the Tertiary.

Acknowledgments

The authors wish to thank Mrs. Sara Ribeiro (Laboratório deGeologia Isotópica da Universidade de Aveiro) for the TIMS analysisand for the guidance and assistance during sample preparation

process in the clean room. This research was financially supportedby the Geobiotec Research Unit (funded by the PortugueseFoundation for Science and Technology, through projectPEst-OE/CTE/UI4035/2014, University of Aveiro, Portugal). I haveto thank Ministry of Sciences, Research and Technology of Iran isthanked for financial support for sabbatical research achieved byRoohollah Miri Bydokhti in Portugal.

References

Abdi, M., Karimpour, M.H., 2013. Petrochemical characteristic and timing of middleEocene granitic magmatism in Kooh-Shah, Lut Block, Eastern Iran. Acta Geol.Sinica 87, 1032–1044.

Angiboust, S., Agard, P., De Hoog, J.C.M., Omrani, J., Plunder, A., 2013. Insights ondeep, accretionary subduction processes from the Sistan ophiolitic ‘‘melange’’(Eastern Iran). Lithos 156–159, 139–158.

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.

Arjmandzadeh, R., Santos, S.A., 2014. Sr–Nd isotope geochemistry andtectonomagmatic setting of the Dehsalm Cu–Mo porphyry mineralizingintrusives from Lut Block, eastern Iran. Int. J. Earth Sci. (GeolRundsch) 103,123–140.

Babazadeh, S.A., de Wever, P., 2004. Early Cretaceous radiolarian assemblages fromradiolarites in the Sistan Suture (Eastern Iran). Geodiversitas 26, 185–206.

Berberian, M., King, G.C., 1981. Towards a paleogeography and tectonic evolution ofIran. Can. J. Earth Sci. 18, 210–265.

Berberian, M., Jackson, J.A., Qorashi, M., Khatib, M.M., Priestley, K., Talebien, M.,Ghafuri-Ashtiani, M., 1999. The 1997 May 10 Zirkuh (Qaenat) earthquake (M.W7.2): Faulting along the Sistan suture zone of eastern Iran. Geophys. J. Int. 136,671–694.

Borg, L.E., Clynne, M.A., Bullen, T.D., 1997. The variable role of slab-derived fluids inthe generation of a suite of primitive calc-alkaline lavas from the southernmostCascades, California. Can. Mineral. 35, 425–452.

Boynton, W.V., 1985. Cosmochemistry of the Rare Earth Elements: MeteoriteStudies, in Rare Earth Element Geochemistry. Elsevier, Amsterdam.

Camp, V.E., Griffis, R.J., 1982. Character, genesis and tectonic setting of igneousrocks in the Sistan suture zone, eastern Iran. Lithos 15, 221–239.

Chappell, B.W., White, A.J.R., 1992. I- and S- type granites in the Lachlan fold belt,transactions of the royal society of Edinburg. Earth Sci. 83, 1–26.

Chappell, B.W., White, A.J.R., 2001. Two contrasting granite type: 25 years later.Aust. J. Earth Sci. 48, 489–499.

Clemens, J.D., Stevens, G., Farina, F., 2011. The enigmatic sources of I-type granites:the peritectic connexion. Lithos 126 (3–4), 174–181.

Defant, M.J., Drummond, M.S., 1990. Derivation of some modern arc magmas bymelting of young subducted lithosphere. Nature 347, 662–665.

Dela Roche, H., Leterrier, J., Grande Claude, P., Marchal, M., 1980. A classification ofvolcanic and plutonic rocks using R1–R2 diagrams and major element analysesits relationships and current nomenclature. Chem. Geol. 29, 183–210.

DePaolo, D.J., 1981. Trace element and isotopic effects of combined wallrockassimilation and fractional crystallisation. Earth Planet. Sci. Lett. 53, 189–202.

Eby, G.N., Woolley, A.R., Din, V., Platt, G., 1998. Geochemistry and petrogenesis ofnepheline syenite: Kasungu-Chipala, Ilomba, and Ulindi nepheline syenite in-trusions, North Nyasa Alkaline Province, Malawi. J. Petrol. 39, 1405–1424.

Esmaeily, D., 2005. Petrology of the Jurassic Shah-Kuh granite (eastern Iran), withreference to tin mineralization. J. Asian Earth Sci. 25, 961–980.

Faure, G., Mensing, T.M., 2005. Isotopes: Principles and Applications. JohnWiley andSons, New Jersey.

Fig. 17. Schematic sketch depicts possible formation model of the tectonic setting and crust–mantle interaction of generated high-K calc-alkaline Oligocene Mahoor granitoidrocks.


Gill, J.B., 1981. Orogenic Andesites and Plate Tectonics. Springer, New York.Griffis, A.R., Magries, H., Abedian, N. and Behrozi, A., 1991. Explanatory text of

Dehsalm (Chahvak). Geological Quadrangle Map 1:250000, No. K6, GeologicalSurvey of Iran, Tehran.

Gust, D.A., Arculus, R.A., Kersting, A.B., 1997. Aspects of magma sources andprocesses in the Honshu arc. Can. Mineral. 35, 347–365.

Hanchar, J.M., Hoskin, P.W.O., 2003. Zircon. Rev. Mineral. Geochem. 53, 1–500.Henderson, P., 1984. Rare Earth Element Geochemistry. Elsevier, Amsterdam, 510

pp.Ishihara, S., 1977. The magnetite- series and ilmenite-series granitic rocks. Min.

Geol. 27, 293–305.Ishihara, S., 1981. The granitoid series and mineralization. Econ. Geol. 75, 458–484.Jacobsen, S.B., Wasserburg, G.J., 1980. Sm–Nd isotopic evolution of chondrites. Earth

Planet. Sci. Lett. 50, 55–139.Karimpour, M.H., Stern, C.R., Farmer, L., Saadat, S., Malekzadeh, A., 2011. Review of

age, Rb–Sr geochemistry and petrogenesis of Jurassic to quaternary igneousrocks in Lut Block, eastern Iran. Geopersia 1, 19–36.

Kemp, A.I.S., Hawkesworth, C.J., Foster, G.L., Paterson, B.A., Woodhead, J.D., Hergt,J.M., Gray, C.M., Whitehouse, M.J., 2007. Magmatic and crustal differentiationhistory of granitic rocks from hafnium and oxygen isotopes in zircon. Science315, 980–983.

Leat, P.T., Smellie, J.L., Millar, I.L., Larter, R.D., 2003. Magmatism in the SouthSandwich arc. In: Larter, R.D., Leat, P.T. (Eds.), Intra-Oceanic SubductionSystems: Tectonic and Magmatic Processes. Geological Society, London, pp.285–313.

Li, X.H., Li, Z.X., Li, W.X., Liu, Y., Yuan, C., Wei, G.J., Qi, C.S., 2007. U–Pb zircon,geochemical and Sr–Nd–Hf isotopic constraints on age and origin of Jurassic I-and A-type granites from central Guangdong, SE China: a major igneous eventin response to foundering of a subducted flat-slab. Lithos 96, 186–204.

Li, X.H., Li, W.X., Wang, X.C., Li, Q.L., Liu, Y., Tang, G.Q., 2009. Role of mantle-derivedmagma in genesis of early Yanshanian granites in the Nanling Range, SouthChina: in situ zircon Hf–O isotopic constraints. Sci. China, Ser. D Earth Sci. 39,872–887.

Maniar, P.D., Piccoli, P.M., 1989. Tectonic discrimination of granitoids. Geol. Soc.Am. Bull. 101, 635–643.

Martin, H., 1987. Petrogenesis of Archaean trondhjemites, tonalites andgranodiorites from eastern Finland: major and trace element geochemistry. J.Petrol. 28, 921–953.

Martin, H., 1999. The adakitic magmas: modern analogues of Archaean granitoids.Lithos 46 (3), 411–429.

Pearce, J.A., 1983. Role of the sub-continental lithosphere in magma genesis atactive continental margins. In: Hawkesworth, C.J., Norry, M.J. (Eds.), ContinentalBasalts and Mantle Xenoliths. Shiva, Nantwich, pp. 230–249.

Pearce, J.A., Harris, N.B.W., Tindle, A.G., 1984. Trace element discriminationdiagrams for the tectonic interpretation of granitic rocks. J. Petrol. 25, 956–983.

Peccerillo, A., Taylor, S.R., 1976. Geochemistry of eocene calc-alkaline volcanic rocksfrom the Kastamonu area (Northern Turkey). Contrib. Miner. Petrol. 58, 63–81.

Saccani, E., Delavari, M., Beccaluva, L., Amini, S., 2010. Petrological and geochemicalconstraints on the origin of the Nehbandan ophiolitic complex (eastern Iran):implication for the evolution of the Sistan Ocean. Lithos 117, 209–228.

Schandl, E.S., Gorton, M.P., 2002. Application of high field strength elements todiscriminate tectonic settings in VMS environments. Econ. Geol. 97, 629–642.

Slama J., Kosler J., Schaltegger U., Tubrett M., Gutjahr M., 2006, New natural zirconstandard for laser ablation ICP-MS U–Pb geochronology. AbstractWP05. WinterConference on Plasma Spectrochemistry, Tucson, pp. 187–188.

Sun, S.S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanicbasalts: implications for mantle composition and processes. Geol. Soc. Lond. 42,313–345.

Tirrul, R., Bell, I.R., Griffis, R.J., Camp, V.E., 1983. The Sistan suture zone of easternIran. Geol. Soc. Am. Bull. 94, 134–150.

Walker, J.A., Patino, L.C., Carr, M.J., Feigenson, M.D., 2001. Slab control over HFSEdepletions in central Nicaragua. Earth Planet. Sci. Lett. 192, 533–543.

Whalen, J.B., Currie, K.L., Chappell, B.W., 1987. A-type granites: geochemicalcharacteristics, discrimination and petrogenesis. Contrib. Miner. Petrol. 95,407–419.

Wiedenbeck, M., Alle, P., Corfu, F., Griffin, W.L., Meier, M., Oberli, F., Von Quadt, A.,Roddick, J.C., Spiegel, W., 1995. Three natural zircon standards for U–Th–Pb, Lu–Hf, trace element and REE analyses. Geostand. Newslett. 19, 1–23.

Whitney, D.L., Evans, B.W., 2010. Abbreviations for names of rock-forming minerals.Am. Mineral. 95, 185–187.

Wilson, M., 1989. Igneous Petrogenesis: A Global Tectonic Approach. Harper CollinsAcademic, New York.

Woodhead, J.D., Eggins, S.M., Gamble, J.G., 1993. Highfield strength and transitionelement systematics in coupled arc–back arc settings: evidence for multi-phasemelt extraction and a depleted mantle wedge. Earth Planet. Sci. Lett. 114, 491–504.

Xu, Y.M., Jiang, S.Y., Zhu, Z.Y., Yang, S.Y., Zhou, W., 2014. Petrogenesis of LateMesozoic granitoids and coeval mafic rocks from the Jiurui district in theMiddle-Lower Yangtze metallogenic belt of Eastern China: geochemical and Sr–Nd–Pb–Hf isotopic evidence. Lithos, 467–484.

Yang, J.H., Wu, F.Y., Wilde, S.A., Xie, L.W., Yang, Y.H., Liu, X.M., 2007. Tracing magmamixing in granite genesis, in situ U–Pb dating and Hf-isotope analysis of zircons.Contrib. Miner. Petrol. 153, 177–190.

Zarrinkoub, M.H., Pang, K.N., Chung, S., Khatib, M.M., Mohammadi, S.S., Chiu, H., Lee,H., 2012. Zircon U–Pb age and geochemical constraints on the origin of theBirjand ophiolite, Sistan suture zone, eastern Iran. Lithos 154, 392–405.


Documents

U–Pb zircon geochronology, Sr–Nd geochemistry ...profdoc.um.ac.ir/articles/a/1049629.pdf · contains various granitoid rocks as dykes and stocks, which intruded into older pyroclastic