Devonian to Permian evolution of the Paleo-Tethys Ocean ...rjstern/pdfs/MoghadamLiGR15.pdf ·...

Gondwana Research 28 (2015) 781–799

Contents lists available at ScienceDirect

Gondwana Research

j ourna l homepage: www.e lsev ie r .com/ locate /gr

Devonian to Permian evolution of the Paleo-Tethys Ocean: New evidencefrom U–Pb zircon dating and Sr–Nd–Pb isotopes of the Darrehanjir–Mashhad “ophiolites”, NE Iran

Hadi Shafaii Moghadam a,b,⁎, Xian-Hua Li a, Xiao-Xiao Ling a, Robert J. Stern c, Mohamed Zaki Khedr d,e,Massimo Chiaradia f, Ghasem Ghorbani f, Shoji Arai d, Akihiro Tamura d

a State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, Chinab School of Earth Sciences, Damghan University, Damghan 36716-41167, Iranc Geosciences Dept., University of Texas at Dallas, Richardson, TX 75083-0688, USAd Department of Earth Sciences, Kanazawa University, Kanazawa 920-1192, Japane Department of Geology, Faculty of Science, Kafrelsheikh University, Egyptf Département de Minéralogie, Université de Genève, Genève, Switzerland

⁎ Corresponding author at: Institute of Geology and GSciences, Beijing 100029, China.. Tel.: +86 10 82998443;

E-mail address: [email protected] (H.S. Mo

http://dx.doi.org/10.1016/j.gr.2014.06.0091342-937X/© 2014 International Association for Gondwa

a b s t r a c t
a r t i c l e i n f o
Article history:Received 22 December 2013Received in revised form 22 June 2014Accepted 22 June 2014Available online 11 July 2014

Handling Editor: I. Safonova

Keywords:Paleozoic ophiolitesU–Pb zircon datingZircon εHf(t)KomatiiteSupra-subduction zone-type magmatism

Middle to Late Paleozoic ophiolites,which are remnants of the Paleo-Tethys Ocean, are aligned in twomain zonesin northern Iran: Darrehanjir–Fariman–Mashhad, and Rasht in the north and Jandagh–Anarak ophiolites to thesouth. Our new U–Pb zircon dating results show that the ~200 km long Darrehanjir–Mashhad mafic–ultramaficbody is not a single ophiolite but a composite igneous complex composed of Permian pillow lavas and pelagicsediments in fault contact with a small outcrop of Devonian intrusive and ultramafic rocks. Darrehanjir intrusiverocks have U–Pb zircon ages of 380.6 ± 3.7 Ma and 382.9 ± 3.7 Ma respectively, ~100 Ma older than publishedages for gabbros and radiolarites intercalatedwith lavas nearMashhad and Fariman. Mantle peridotites from theDevonian complex contain low Cr# spinel, similar to that in MORB-type peridotites. Devonian Darrehanjirgabbros and Permian Mashhad sequences both have boninitic and calc-alkaline signatures, respectively. Theδ18Ozircon values from the Devonian ferrodiorite (δ18Ozircon ~ 4.6 ± 0.3‰) are slightly lower than the 5.2 to5.4‰ expected for MORB-type zircons whereas Devonian plagiogranitic zircons mostly have δ18Ozircon b5‰,perhaps reflecting involvement of hydrothermally altered crust. Similar, strongly positive values of zirconεHf(t) for plagiogranite (av. +14.9) and ferrodiorite (av. +13.8) indicate melt derivation from depleted astheno-sphere. Darrehanjir–Mashhad ophiolitic rocks can be divided into groups with high εNd (N10.3) and low εNd(b5.4) for both Permian and Devonian suites. Most Darrehanjir–Mashhad rocks are characterized by radiogenic207Pb/204Pb and 208Pb/204Pb, indicating the involvement of subducted terrigenous sediments in the source. TheMashhad–Darrehanjir mafic–ultramafic complex demonstrates that this part of Paleo-Tethys evolved from oceaniccrust formation above a subduction zone in Devonian time to accretionary convergence in Permian time. IranianPaleozoic ophiolites and oceanic igneous complexes along with those of the Caucasus and Turkey in the west andAfghanistan, Turkmenistan and Tibet to the east, define a series of diachronous subduction-related marginalbasins that were active from at least Early Devonian to Late Permian time.

© 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

1. Introduction

Ophiolites are fragments of oceanic lithosphere tectonically emplacedonto continents during orogeny. They are generally exposed alongsuture zones, and play a key role in reconstructing the tectonic historyof orogenic belts (e.g., Coleman, 1977; Dilek, 2003). Determiningwhether or not an assemblage of mafic and ultramafic rocks is anophiolite can be challenging. A complete “Penrose” ophiolite consists

eophysics, Chinese Academy ofFax.: +86 10 62010846.ghadam).

na Research. Published by Elsevier B.

of a reasonably intact sequence of oceanic crust and mantle comprisingfrom top to bottom: pillowed basalts, sheeted dikes, cumulate maficand ultramafic rocks, and tectonized peridotite (Anonymous, 1972).Most ophiolites are highly disrupted by faulting and some of these com-ponents may be missing, especially sheeted dikes. Some Ligurianophiolites have little gabbro or basalt (Nicolas, 1989). But in all casesophiolite components formed approximately at the same time, perhapsdiffering in age by nomore than ~10Ma. If parts of an ophiolitic assem-blage are much different than ~10 Ma, then it is unlikely to be anophiolite but some other kind of mafic–ultramafic complex. We hereinshow that the Mashhad–Darrehanjir “ophiolite” contains componentsthat differ in age by much more than 10 Ma and thus is a composite

V. All rights reserved.

http://crossmark.crossref.org/dialog/?doi=10.1016/j.gr.2014.06.009&domain=pdf

http://dx.doi.org/10.1016/j.gr.2014.06.009

mailto:[email protected]


http://www.sciencedirect.com/science/journal/1342937X

782 H.S. Moghadam et al. / Gondwana Research 28 (2015) 781–799

mafic–ultramafic complex. Nevertheless, this complex contains impor-tant information about Paleo-Tethys.

Ophiolites are widely distributed in Iran and can be subdivided intotwo main age groups (Fig. 1): 1) Paleozoic ophiolites in northern Iranand 2) Mesozoic ophiolites further south, around the main Cadomiancontinental blocks (e.g., Shafaii Moghadam and Stern, 2011; ShafaiiMoghadam et al., 2013). Paleozoic ophiolites of Iran help define thelocation of Paleo-Tethys, and such ophiolites can be traced to the eastand west. Paleozoic ophiolites of southwest Asia are exposed inTurkey (Kure mélange) and the Caucasus and pass through Iran intoAfghanistan, Turkmenistan and Tibet (e.g., Su et al., 2011; Shi et al.,2012; Meng et al., 2013). Development of Paleozoic ophiolites in theseregions reflects a long history of continental rifting, ocean propagation,subduction initiation along the southernmargin of Eurasia, exhumationof high-pressure rocks, and closure of the Paleo-Tethys oceanic basin(e.g., Stampfli and Borel, 2002; Bagheri and Stampfli, 2008; Jian et al.,2009a,b; Dai et al., 2011; Rolland et al., 2011; Buchs et al., 2013;Omrani et al., 2013; Zanchetta et al., 2013; Zhai et al., 2013). Any linksof Iranian Paleo-Tethys with that of Paleozoic orogens in the Uralsto the north and Central Asian Orogenic Belt (CAOB) to the NE are

Fig. 1. Simplified geological map of Iran emphasizin

buried beneath younger deposits in Turkmenistan, Uzbekistan, andKazakhstan.

In southern Eurasia, the Paleo-Tethys Ocean opened in Early Paleo-zoic time and closed during Triassic time, resulting in Eo-Cimmerian de-formation in northern Iran and Afghanistan, followed by Middle–LateJurassic compression (Boulin, 1988; Zanchi et al., 2009). Paleo-Tethysopening is reflected in widely distributed alkali to tholeiitic continentalflood basalts (Soltan–Meidan basalts), felsic–mafic plutons (with agesof ca. 460Ma; Shafaii Moghadam and Stern, 2014) and dolomites, evap-orites and terrigenous sediments in the Ordovician Ghelli to LowerDevonian Padeha Formations in north Iran (Stampfli, 1978; Aharipouret al., 2010). These data show that followingOrdovician–Silurian rifting,seafloor spreading to widen Paleo-Tethys was diachronous, varying inage from Devonian to Permian time.

Paleozoic remnants are mainly distributed in north Iran, wherenorthward subduction of Paleo-Tethys and subsequent collision be-tween the Iranian Cimmerian blocks and the Turan block (Eurasia)occurred (Fig. 2). These ophiolitic slices comprise Mashhad, Fariman–Darrehanjir (in Kopet Dagh), Rasht, Takab and Jandagh–Anarakophiolites (Fig. 1). The 200 km long Paleozoic Darrehanjir–Mashhad

g the main ophiolitic belts (thick dashed lines).

Fig. 2. Structural and geological map of northern Iran showing locations of Paleozoic ophiolites and associated units.Modified after Zanchi et al. (2009).

783H.S. Moghadam et al. / Gondwana Research 28 (2015) 781–799

mafic–ultramafic complex in northeast Iran has long been interpretedas an ophiolite (Alavi, 1991; Sheikholeslami and Kouhpeyma, 2012),unconformably covered byUpper Triassic to JurassicMashhad phyllites.The complex is best exposed in three places: west of Mashhad,north of Fariman and northeast of Darrehanjir (Figs. 2 and 3). Expo-sures of mafic–ultramafic lavas and gabbros near Fariman andDarrehanjir are also called the Aghdarband ophiolite. Biostratigraphic

Fig. 3. Simplified geologicalmap of theMashhad–Fariman–Darrehanjir ophiolites. Note that pluthe map does not allow these to be separated on this map.Modified after Zanchetta et al. (2013).

ages for radiolarites intercalated with turbidites and these lavas areEarly Permian (Eftekharnezhad and Behroozi, 1991), Late Early Permianor Middle Permian (Zanchetta et al., 2013), ~260–290 Ma. These agreewith 40Ar/39Ar dating of hornblende gabbros from the Mashhadophiolite with ages of ca. 288 to 282 Ma (Ghazi et al., 2001) and/orU–Pb zircon dating (262.3 ± 1Ma) of Anarak plagiogranites (Paleozoicophiolite outcrops in central Iran; Fig. 1). Early Permian ages for

tonic rocks (gabbros and plagiogranites) are at the contactwith peridotites, but the scale of


Darrehanjir–Fariman radiolarite micro-faunas may show the lastphases of Paleo-Tethys evolution. The Permian age for interbeddedradiolarites and lavas associated with Mashhad–Darrehanjir gabbroscould represent arc or back-arc extension following subduction androll-back of Paleo-Tethys lithosphere (Zanchetta et al., 2013).

In this paper, we report new U–Pb ages and O–Hf isotopic composi-tions of zircons, whole rock major, trace elements and Sr–Nd–Pbisotopes as well as mineral compositions of the Mashhad, Farimanand Darrehanjir mafic–ultramafic complex. Our results reveal that theDarrehanjir–Mashhad “ophiolite” is a composite igneous complex;Ar–Ar ages and biostratigraphy from the Fariman–Mashhad ophiolitesindicate Permian age but our U–Pb zircon ages indicate Devoniancrystallization ages for Darrehanjir plutonic rocks. These are both never-theless fragments of Paleo-Tethys, and we refer to them as such. Thisdiscovery provides additional constraints on the configuration of thePaleo-Tethys during Devonian to Permian time.

2. Geological setting

Below we separately discuss the field relationships and petrology ofrocks from each of the complexes: Mashhad, Fariman and Darrehanjir.

2.1. Darrehanjir mafic–ultramafic rocks

There is a small outcrop (~5 × 2 km) of plutonic and volcanic rockssoutheast of Mashhad city at Darrehanjir (Fig. 3), near Aghdarbandvillage. The Paleo-Tethys oceanic fragments here are fragmented andcrushed and their contacts with younger strata are mostly faulted.

Fig. 4. Lithological columns showing pseudo-stratigraphic

Darrehanjirmafic–ultramafic complex consists of amantle sequence in-cluding serpentinized lherzolites and harzburgites with dunite screens/layers and gabbroic lenses (~2 × 1 km). Clinopyroxenite to wehrliticdikes and sills (av. 20–30 cm wide, but up to 50 cm wide) crosscut themantle peridotites (Figs. 4 and 5A). Peridotites were impregnated viareaction with clinopyroxenitic/wehrlitic sills. Gabbros are medium- tocoarse-grained and locally show layering. These gabbros display a well-defined, steep north-dipping magmatic foliation (Zanchetta et al.,2013). The Devonian gabbros have faulted contacts with peridotites(Fig. 5B). They vary from dry gabbros, leucogabbros, and ferrogabbros–ferrodiorite to amphibole-bearing varieties. Leucogabbros are abundantand are enriched in plagioclase with minor clinopyroxene whereasmelagabbros are enriched in clinopyroxene with rare orthopyroxene.Early plagiogranite, rodingitized gabbroic, and last-stage basaltic–diabasicdikes crosscut the gabbro (Fig. 5C). Amphibole-bearing gabbros anddiorites are intercalated with amphibole-free gabbros. Because mostvolcanic rocks are exposed near Fariman, we suspect that those nearDarrehanjirmay be a tectonic slice of Fariman volcanic rocks. The volcanicsequence includes basaltic rocks with intercalated carbonate, tuff,radiolarite and radiolarian shale near the base grading up into Permianturbidite and phyllitic shale with intercalated volcanic rocks and recrys-tallized limestone (Fig. 4). Late Permian or younger Qara-Gheitan Forma-tion (comprising red to green shale, sandstones, mafic lavas and tuffs)with basal conglomerates (including ophiolitic fragments) rests conform-ably on the Darrehanjir ophiolite (Eftekharnezhad and Behroozi, 1991).The plutonic pebbles of basal conglomerates are mostly granite, alkali-granite, and minor monzonite. U–Pb zircon ages of granitoid pebblesyield 343 Ma (Early Carboniferous; Karimpour et al., 2011) and 306.7 ±

rock units of the Darrehanjir and Mashhad ophiolites.

Fig. 5. Field photographs of the Darrehanjir–Mashhad Paleozoic ophiolites. A — Clinopyroxenitic dikes/veins within the Darrehanjir lherzolites. B — The faulted contact between theDarrehanjir gabbros and peridotites. C — Plagiogranitic dike within the Darrehanjir gabbros. D and E — Stratigraphic contact between Miankuhi Formation with basal conglomerate(E) and the Darrehanjir ophiolites. F and G — Outcrop of pillow lavas in the Fariman and Mashhad ophiolites. H — Intercalation of ultramafic (komatiite) lavas with terrigenous/pelagicsediments in the Mashhad ophiolite.


7 and 326.5±6.7Ma (Late Carboniferous) (Zanchetta et al., 2013). Thesegranitic fragments have initial 87Sr/86Sr that range from 0.7062 to 0.7068and εNd values ~ −5, indicating that the granite melt involved older

continental crust (Karimpour et al., 2011). In Darrehanjir village, themafic rocks are overlain unconformably by Upper Triassic sandstonesand conglomerates (with fossil wood) of the terrestrial Miankuhi


Formation (Fig. 5D and E). This sequence is also similar to the MiddleJurassic Kashafrud Formation, which is generally conglomeratic at itsbase and is dominated by thick siltstone, sandstone and shale (Robertet al., 2014).

2.2. Fariman mafic–ultramafic rocks

Mafic–ultramafic rocks are also found west and southwest ofDarrehanjir, along the Fariman–Torbat-e-Jam Fault (Fig. 3). The Farimansequence consists of two units (Zanchetta et al., 2013): 1) a lower mé-lange unit of mica schists, phyllites, metabasalts and marbles withserpentinites and 2) an upper, more coherent unit including Permiancarbonates with abundant basaltic lava flows interbedded withvolcaniclastic sediments (Fig. 4). Our field observations show that ul-tramafic lava flows are also present (around Sefid-Sang and Senjedakvillages), intercalated with Permian radiolarite. Recrystallized lime-stones, tuffaceous slates and phyllites are unconformably overlain bypelagic sediments and turbidites. Mafic lavas occur as massive flowsbut mostly as pillowed lavas and are associated with metamorphosedlimestone (Fig. 5F). These lavas were metamorphosed at greenschistfacies and contain secondary epidote and chlorite. Permian high-Nb,OIB-type (see next sections) basaltic lavas (transitional basalts ofZanchetta et al., 2013) are intercalated with metamorphosed pelagiclimestone. Peridotite and serpentinite are rare and occur as tectonicslices in fault contact with volcano-sedimentary units. Biostratigraphicdata show a Late Early to Middle Permian age for the sediments(Zanchetta et al., 2013). Further south, both the Darrehanjir and theFariman ophiolites are unconformably overlain by clastic sediments ofthe Middle Jurassic (Bajocian) Kashafrud Formation. Zanchetta et al.(2013) suggested that volcano-sedimentary units of the Fariman andthe Darrehanjir ophiolites were deposited during Permian time in asubsiding basin where siliciclastic turbidites derived from the erosionof a magmatic arc and its basement were deposited, interfingeredwith carbonates and basaltic lava flows with calc-alkaline and transi-tional (alkaline?) affinities. They interpreted the Fariman–Darrehanjirophiolites as remnants of a magmatic arc developed at the southernmargin of Eurasia, above the north-dipping Paleo-Tethys subductionzone.

2.3. Mashhad mafic–ultramafic rocks

Remnants of Paleo-Tethys oceanic sequences near Mashhad city(Fig. 3) include three distinct rock assemblages (Alavi, 1991; Ghaziet al., 2001): 1) ophiolite (Mashhad–Fariman), 2) deep sea turbiditesand other metamorphosed sedimentary rocks (interpreted as an accre-tionary prism by Alavi, 1991and Ruttner, 1993); and 3) pyroclasticrocks. The ophiolite comprises ultramafic rocks, gabbro-diorite (locallylayered), and pillow lava (Fig. 5G). Metachert interbedded with marble(originally pelagic limestone) and meta-terrigenous sediments (turbi-dites) are locally interlayered with mafic–ultramafic lavas (Figs. 4 and5H). Layered gabbro and sheeted dikes aremissing (Alavi, 1991). Becauseof pervasive serpentinization, Mashhad ophiolite ultramafic lavas andmantle harzburgites are difficult to distinguish in the field. Two featureshelp the distinction; i) nearly holocrystalline ultramafic lavas, withrounded olivines (without spinifex texture); and 2) lavas are interbeddedwith marbles, slates and phyllites (originally turbidites).

In Virani village (Fig. 3), a gabbroic dike (2–3 m) crosscutsserpentinized peridotite. The Virani region contains more mafic (basal-tic) and ultramafic rocks whereas the Mashhad exposes more volcanicand sedimentary rocks. Basalts in the Mashhad mafic–ultramafic com-plex show both E-MORB and arc-type geochemical signatures (Ghaziet al., 2001). West of Mashhad, Majidi (1981) recognized 15 lavaflows that change from ultramafic to tholeiitic basalt up-section over astratigraphic interval of about 2000 m. Ultramafic pillow lavas are alsofound 80 km southeast of Mashhad, underlain by hyaloclastic rocksand overlain by chert. The Mashhad complex is thought to be Early

Permian, based on biostratigraphy and radiometric age determinations.Pelagic conodonts in chert interbedded with pillow lava, phylliticslate and sandy chert are Late Kungurian (Early Permian; Kozur andMostler, 1991). Gabbros yield hornblende 40Ar/39Ar crystallizationages between 281.7 and 287.6 Ma (Artinskian to Sakmarian of EarlyPermian; Ghazi et al., 2001). The Mashhad ophiolite is overlain bymetamorphosed sedimentary rocks consisting of slate, phyllite, schist,and marble with intercalated volcanic rocks (~1–1.5 m. thick for eachlava layer) (Alavi, 1991). Clastic metasediments are interpreted asdeep-water flysch deposits, thought to have accumulated in a Permo-Triassic accretionary prism (Alavi, 1991; Ruttner, 1993). Acidic to inter-mediate pyroclastic rocks (with calc-alkaline signatures) includinglapilli tuffs and tuffs associated with lavas in the Mashhad ophiolitethicken toward the southeast (Torbat-e-Jam). Such pyroclastic and vol-canic rocks are considered to reflect Silk Road magmatic arc explosivevolcanism (Alavi, 1991), suggesting that these are arc-related (forearc/backarc) ophiolites. The afore-mentioned ophiolitic metasedimentaryrocks are overlain unconformably by Late Triassic–Early Jurassic shale,sandstone, and conglomerate (Kashafrud Formation).

3. Petrography

3.1. Darrehanjir mafic–ultramafic rocks

Darrehanjir lherzolites are variably serpentinized but have relicts ofolivine and spinel. Less altered varieties contain large orthopyroxene(4–5mm)porphyroclasts and smaller (1–2mm) clinopyroxene. Spinelsare red–brown and vermicular to anhedral. Clinopyroxenes are mostlydistributed around the large orthopyroxenes. Dunites are highlyserpentinized with relicts of olivine and brown spinels. Some duniteshave trace clinopyroxene, due to impregnation by wehrlitic dikes.Wehrlitic to clinopyroxenitic dikes/sills include large clinopyroxenes(N5 mm) with interstitial olivine.

Darrehanjir leucogabbros/gabbros show cumulate texture andcontain large plagioclase (2–3 mm av.). Fine-grained, anhedralclinopyroxenes (0.5–1 mm) are interstitial between plagioclases.Orthopyroxene occurs rarely. Brown amphiboles rim clinopyroxenesand occur as anhedral, vermicular crystals. Ferrodiorites have alteredplagioclases and fine-grained amphibole aggregates. Clinopyroxeneis rare, but coarse-grained apatite and iron oxides are common.Rodingites contain hydrogrossular, secondary diopside, chlorite andpectolite. Diabasic dikes are characterized by plagioclase laths and fine-grained (0.3–0.5 mm av.) brown amphiboles. Plagiogranites havecataclastic texture, characterized by large (av. 4–5 mm) deformed pla-gioclases and recrystallized quartz neoblasts. The rock has sufferedmylonitic metamorphism, evidenced by recrystallized plagioclaseand quartz. Quartz ribbons (with stretched neoblasts) are common,suggesting lower amphibolite facies metamorphism.

3.2. Fariman mafic–ultramafic complex

Fariman ultramafic lavas are altered. In highly altered varieties,rounded olivine pseudomorphs are abundant. Between these olivinepseudomorphs, there are interstitial coarse-grained (N2 mm) tofine-grained (0.2–0.3 mm) clinopyroxenes and orthopyroxenes(CpxN N Opx). The pyroxene shape follows from the spaces betweenolivines. Very fine-grained, brown amphibole needles are present aroundclinopyroxene and in the serpentine-rich groundmass. Amphibole alsooccurs as green–brown microphenocrysts. Moderately altered ultra-mafic lavas contain both coarse-grained (~2 mm) and fine-grained(av. 0.5 mm) rounded olivines. Anhedral clinopyroxenes are interstitialbetween olivines. Brown amphibole microphenocrysts are altered toactinolite around their rims. Serpentine occurs between olivine and py-roxene phenocrysts andmay be alteration of ultramafic glass. Rare skel-etal plagioclases (altered into clay) are overgrown by clinopyroxene.Holocrystalline to porphyritic pillowed and massive basaltic lavas


include feather-like or dendritic clinopyroxene and rare skeletal plagio-clase, showing a quenched, disequilibrium texture. Their groundmassglass is mildly to highly palagonitized. Last-stage, Permian basalticlavas (OIB-type varieties; transitional basalts of Zanchetta et al., 2013)contain sanidine microlites.

3.3. Mashhad mafic–ultramafic complex

Mashhad ultramafic lavas are 70–100% serpentinized and containrounded olivine relicts. Between olivines, there are anhedral, interstitialclinopyroxenes. The Mg-rich nature of these lavas could partly reflectolivine accumulation. Large clinopyroxene phenocrysts poikiliticallycontain rounded olivine. Brown anhedral to subhedral amphiboles arealso interstitial. Traces of tiny black spinels are notable. No plagioclaseis observed. The ultramafic lavas have nearly holocrystalline texture.Mafic lava flows and pillow lavas have intergranular textures with pla-gioclase and clinopyroxenemicrolites in a highly altered glassy ground-mass. Gabbros contain large (2–3 mm) clinopyroxene and plagioclasephenocrysts. Clinopyroxene is altered into tremolite and calcite.

4. Mineral major and trace element composition

We analyzed thirteen samples of Darrehanjir peridotite and gabbroand Farriman–Mashhad ultramafic–mafic lavas for mineral composi-tions, major and trace elements. Analytical methods are available inSupplementary File 1. Mineral major and trace element data for ana-lyzed samples are available in Supplementary Files 2 and 3.

4.1. Olivine

Darrehanjir lherzolite olivine is represented byMg# (100 Mg/(Mg+Fe+2)) and NiO content ranging from 90.5 to 91.2 and ~0.3–0.4 wt.%respectively (Supplementary File 2). Forsterite content of olivinefrom Farriman–Mashhad mafic lavas varies from 84.7 to 91.5 withnearly constant NiO content, 0.3–0.4 wt.%, as expected for mantle

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

A

abyssal peridotiteCPX

#Mg

Al2O3 (wt.%)

lherzoliteclinopyrox. dike dunite

Cpx in equilibriumwith N-MORB

Na2O (wt.%)

0.95 0.94 0.93 0.92 0.91 0.90 0.89

0 0.1 0.2 0.3 0.4 0.5 0.6TiO2 (wt.%)

0

0.1

0.2

0.3

0.4

B

CPX

gabbro

mafic lava

ultramafic lava

Fig. 6. Compositional variations of clinopyroxene and amphibole from different rock unclinopyroxenes; B — Na2O versus TiO2 for peridotite clinopyroxenes and C — Al2O3 vs. TiOclinopyroxenes. Fields outline clinopyroxene compositions in boninites (Van der Laan et al., 199mid-ocean-ridge basalt (N-MORB) (Stakes and Franklin, 1994). D— The composition of amphi

olivine (Supplementary File 2). Fariman ultramafic lavas contain olivinewith high forsterite content (88.7–90.9), similar to olivines of Mashhadultramafic lavas (85.7–86.9). Their NiO contents are also similar,~0.4 wt.% (Supplementary File 2). Farriman basaltic lavas have olivinewith lower forsterite content (84.8–91.5) and NiO (0.29–0.44 wt.%)contents (Supplementary File 2).

4.2. Spinel

Darrehanjir lherzolite spinel is characterized by low Cr# (Cr/Cr + Al),ranging between 0.2 and 0.4, similar to those of less depleted abyssalperidotites (Fig. 7A). These spinels have low TiO2 (0.05–0.1 wt.%) andhigh Al2O3 (33.2–48 wt.%), again similar to those of abyssal peridotites(Fig. 7B and C). Dunites are characterized by moderate Cr# spinels;~0.5, but with high TiO2 content (0.2–0.3 wt.%). Clinopyroxenitic dikespinels have low Cr#; ~0.3. Spinels from ultramafic lavas contain higherCr# spinels (0.6–0.7), with variable Al2O3 (~12.6–18.4 wt.%) and TiO2

(0.55–1.74) abundances, similar to those of arc tholeiites (Fig. 7C).Fariman basaltic lavas are represented by slightly lower Cr# spinels(0.55–0.75) but higher TiO2 (0.53–3.3) spinels.

4.3. Orthopyroxene

Darrehanjir lherzolite orthopyroxenes are characterized by Mg#~91 and high Al2O3 (2.7–3 wt.%) (Supplementary File 2), whereasorthopyroxene from mafic–ultramafic lavas is less magnesian andaluminous, represented by 76 to 86 Mg# and low Al2O3; 1.1–1.9 wt.%.

4.4. Clinopyroxene

Darrehanjir lherzolite clinopyroxene is diopsidewith highMg# (93–94) and Al2O3 content (2.6–4.7 wt.%) indistinguishable from duniteclinopyroxene (Mg# = 93–94; Al2O3 = 1.5–3.9 wt.%) (Fig. 4A).Clinopyroxene from clinopyroxenitic dikes has similar Al2O3 con-tent (1.8–3.3 wt.%), but lower Mg# (88–92) (Fig. 6A). Lherzolite

0

1

Si (tetrahedra site)

Mg/

(Mg+

Fe)

Tremolite

Actinolite

Ferro-actinolite

FeActHbl

ActHbl

Tr Hbl

Magnesio-hornblende

Ferro-hornblende

TschHbl

Tschermakite

FeTschHbl

Ferro-Tschermakite

D

0

2

4

6

8 Al2O3 (wt.%)CPX

C

TiO2+Cr2O3

Back-arc basin basalt

N-MORB

Arc tholeiite

Boninite

8.0 7.5 7.0 6.5 6.0 5.5

0 0.5 1.0 1.5 2.0 2.5 3.0

its of the Darrehanjir–Mashhad ophiolites. A — Al2O3 versus Mg# for peridotite2 and Cr2O3 adapted after Hout et al. (2002) for peridotite and ultramafic–mafic rock2), island-arc tholeiites, and back-arc basin basalts (Hawkins and Allan, 1994), and normalbole from ultramafic–mafic lavas in Mg/(Mg+ Fe) vs. Si (IV) diagram (Leake et al., 1997).

Aby

ssal

per

idot

ites

SS

Z pe

ridot

ites

Boninites

0

0.2

0.4

0.6

0.8

1.0

Cr#

Cr/(

Cr+

Al)

00.20.40.60.81.0Mg# Mg/(Mg + Fe+2)

Parti

al m

eltin

g tre

nd

A

Cr# Cr/(Cr+Al)

TiO

2(w

t. %

)

B

Abyssal peridotites

Darrehanjir lherzoliteDarrehanjir dunite

Fariman ultramafic-mafic lavasDarrehanjir clinopyroxenite

0 10 20 30 40 500.01

0.1

1

10

C

MORB

Island-arc tholeiiteOIB

MORBperidotite

SSZperidotite

TiO

2in

spi

nel

Al2O3 in spinel0.2 0.4 0.6 0.8 1.0

0.2

0.4

0.6

0

Boninites

SSZ peridotites

0.7

Fig. 7. Cr# vs. Mg# (A) and TiO2 vs. Cr# (B) diagrams (modified after Dick and Bullen, 1984) displaying the composition of peridotite and ultramafic–mafic rock spinels from theDarrehanjir–Mashhad ophiolites. C—Diagram (after Kamenetsky et al., 2001) showing TiO2 against Al2O3 contents of spinels, in order to discriminate between various types of peridotitesand lavas.


clinopyroxenes have high Na2O and TiO2 contents (0.1–0.2 and0.2–0.3 wt.% respectively), similar to magmatic clinopyroxenesfrom clinopyroxenitic dike (Fig. 6B), suggesting that the Darrehanjirperidotites are relatively undepleted.

Darrehanjir gabbro clinopyroxene Mg# is lower than that ofultramafic–mafic lavas (71–80 vs. 74–91) (Supplementary File 2).Compositional contrasts between clinopyroxenes from different maficrock units of the Darrehanjir–Mashhad complexes are revealed bya plot of Al2O3 content versus Cr2O3 + TiO2 (Fig. 6C). Al2O3 (3.4–5.2 wt.%) and TiO2 (0.7–0.9 wt.%) of gabbro clinopyroxenes arerelatively high. Al2O3 and TiO2 contents of Darrehanjir–Mashhadultramafic–mafic lava clinopyroxenes are variable; 1.9–6.4 and 0.3–3.3wt.% respectively. Higher values are restricted to the last-stage Farimanhigh-Nb OIB-like basaltic lavas, whereas the ultramafic lavas containless Al2O3 and TiO2 (Supplementary File 2; Fig. 6C). In the Al2O3 versusCr2O3 + TiO2 diagram (Hout et al., 2002), clinopyroxenes are composi-tionally similar to those of back-arc basin basalts and MORBs (Fig. 6C).The Fariman OIB-type basalts (sample F12–35) have higherCr2O3 + TiO2 values.

4.5. Amphibole

Brown to greenish magmatic amphiboles from Darrehanjir–Mashhad ultramafic–mafic lavas display magnesio- to ferro-hornblende,

Abyssal peridotite

MOR cumulate

Ultra-depleted melt, MAR

detection limit

10

1

0.1

0.01La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

0

SSZ peridotite

A

Cpx/Ch

ondrite

Cpx/Ch

ondrite

Fig. 8. Rare earth and trace element abundances of clinopyroxene in the Aghdarband lherzolite(1989). Fields for abyssal and supra-subduction zone (SSZ) peridotite clinopyroxene are from Jfrom the Mid-Atlantic Ridge (MAR) is from Sobolev and Shimizu (1993), and the field for MOR

tschermakite to tschermakitic hornblende composition (Fig. 6D). Theseamphiboles have variable Mg# (39–84), Al2O3 (2.5–11 wt.%) and TiO2

(0.4–4.5 wt.%) (Supplementary File 2).

4.6. Feldspar

Plagioclase in Darrehanjir gabbros is An 68–86. Plagioclase microlitesin Mashhad ultramafic lavas are altered into secondary albite duringsaussuritization. Sanidine laths in OIB-type basalts have 97–98% ortho-clase (Or) end member (Supplementary File 2).

4.7. Trace & REE composition of clinopyroxene

Clinopyroxene in Darrehanjir lherzolites exhibits similar REEpatterns to that of abyssal peridotites, but with slightly lowerHREE con-tents (Fig. 8a), further indicating that this peridotite is not very deplet-ed. Depletions in Zr, Ti and Sr are conspicuous (Fig. 8). Magmaticclinopyroxenes from Darrehanjir clinopyroxenitic dike are enriched inbulk REEs, but show LREE-depleted patterns (Fig. 8) that differ fromthose of lherzolites. Clinopyroxenitic dike clinopyroxenes are alsodepleted in Nb, Zr and Ti. Their trace element patterns differ fromthose of MOR cumulate clinopyroxenes and seem to have crystallizedfrom an E-MORB or OIB-like melt.

Hess Deep wehrlite

detection limit

10

1

0.1

.01Nb La Ce Sr Pr Nd Zr Sm Eu Gd Ti Tb Dy Y Ho Er Tm Yb Lu

B

clinopyroxenitic dike

lherzolite

and clinopyroxenitic dike. Chondrite normalization values are from Sun and McDonoughohnson and Dick (1992) and Johnson et al. (1990). The composition of ultra-depletedmeltcumulate clinopyroxene is from Ross and Elthon (1993).


5. Geochemistry of rock units fromDarrehanjir–Mashhad ophiolites

We selected 32 samples (without veins filled with secondary min-erals such as magnesite, calcite and/or quartz) from the Darrehanjir–Mashhad ophiolites for whole rock analysis. Analytical methods forwhole rockmajor, trace, REE and Sr–Nd–Pb isotopic analyses, U–Pb zir-con dating and zircon O–Hf isotopes are presented in SupplementaryFile 1. Bulk rock major and trace element data are available at Supple-mentary File 4. We sampled Darrehanjir gabbros, plagiogranites and as-sociated dikes, where our U–Pb SIMS dating (see next section) indicatesa Devonian crystallization age for these rocks, in contrast to Mashhad–Fariman mafic–ultramafic rocks as well as gabbros where previousAr–Ar (for gabbros; Ghazi et al., 2001) and biostratigraphic ages (forultramafic–mafic lavas) indicate Early to Middle Permian ages (Kozurand Mostler, 1991; Zanchetta et al., 2013).

Darrehanjir gabbros have similar SiO2 contents ranging from 44.7 to48 wt.%, except rodingitized gabbros with lower SiO2 abundance (Sup-plementary File 4). TiO2 contents and Mg# vary between 0.03 and1.06 wt.% and 49–92.7 respectively. Plagiogranite has high SiO2

(63.4 wt.%), but low TiO2 (0.14 wt.%) contents. Late-stage diabasicdikes have nearly constant SiO2 (42.7–45.5 wt.%) and higher TiO2

(1.3–1.4 wt.%) abundances. Darrehanjir igneous rocks have a widerange of FeO/MgO (~0.1 to ~3.3) (Fig. 9D). The gabbros are character-ized by low Ti/V similar to calc-alkaline rocks. Diabasic dikes havehigher Ti/V, resembling MORB (Fig. 9C). Gabbroic rocks have low bulkREE content with La(n)/Yb(n) between 0.3 and 4.4; depletion inNb (Nb(n)/La(n) = 0.03–0.5) and Zr and enrichment in Eu and Sr(Fig. 10B). These characteristics are similar to those of cumulate rocks,crystallized from a depleted (boninitic-type) melt. Rodingitized dikesare similar to gabbros except sample DA12–43 with high La(n)/Yb(n)(60.2) but are also depleted in Nb, similar to calc-alkaline rocks.Plagiogranitic dike has spoon-shaped REE pattern with depletion inNb–Ti and enrichment in large-ion lithophile elements (LILEs). Diabasic

39 41 43 45 47 49 51 53 55 57 59 61 63 65SiO2 (wt.%)

0

1

2

3

4

Na2

O+K

2O

basanitetephrite

picrobasaltbasalt

basalticandesite andesite

boniniteMgO>8% & TiO2<0.5%

komatiiteMgO>18% & TiO2<1%

A

0 5 10 15 20 25Ti/1000

0

100

200

300

400

500

600

V

Ti/V=10Ti/V=20

Ti/V=50

Ti/V=100

MORBBoninite IAT

Oman V1 lavas

Oman V2 lavas

IBM forearc lavas

IBM boninites

C

Fig. 9. A and B— Na2O+ K2O vs. SiO2 and MgO diagrams (modified after LeBas, 2000) to discriophiolites. C— Ti versus V diagram (after Shervais, 1982) for theDarrehanjir–Mashhadmagmatilavas of the Oman ophiolite (data from Alabaster et al., 1982) are shown. D — FeOt/MgO versmagmatic rocks. Boundaries between tholeiitic and calc-alkaline suites (thin solid line) and(1974) and Arculus (2003), respectively.

dikes have calc-alkaline signature with high La(n)/Yb(n) (8.9–9.6), en-richment in LILEs and depletion in Nb (Nb(n)/La(n) = 0.57) (Fig. 10B).

Fariman lavas can be divided into ultramafic lavas with low SiO2

(39.9–41.5 wt.%) and TiO2 (0.5–0.8 wt.%) but higher Mg# (79.5–82.5)and mafic lavas with higher SiO2 (44.1–50.8 wt.%), TiO2 (0.8–1.4 wt.%)and lowerMg# (58.5–68.3). Ultramafic lavas are particularly interestingand the role of alterationmust be considered. Although these rocks havehigh LOI values,we do not think that alterationwas responsible for theiroverall composition. Alteration can lead to Mg enrichment but we seeno evidence that this happened for these lavas; for example there arenomagnesite veins in the rocks. Studies of serpentinized abyssal perido-tites show that most of these rocks that have suffered CaO (and/or CO2)gain and MgO loss (Menzies et al., 1993; Snow and Dick, 1995).

In diagrams plotting Na2O+ K2O versus SiO2 and MgO (anhydrous-basis; modified after LeBas, 2000), the Fariman pillowed and massivelavas have basaltic characteristics but ultramafic lavas are komatiitic(Fig. 9A and B). Komatiitic lavas have low FeO/MgO (0.4–0.5) (Fig. 9D)and arc-like Ti/V (~20–31) (Fig. 9C). Mafic lavas have higher FeO/MgO(0.8–1.3) and variable Ti/V ratios: low (20.4–24.5) in low-Ti basaltsand high (29.4–36.1) in high-Ti lavas (Fig. 9C and D). Farimankomatiites have low bulk REE contents, but La(n)/Yb(n) = 1.1–2.8(Fig. 10). Depletion in Nb is conspicuous (Nb(n)/La(n) ~ 0.6–1). Farimanpillow lavas are LREE-enriched (La(n)/Yb(n) = 4.5–7.5) with slight Nbdepletion, but enriched LILEs and Th (Fig. 10D). Such HFSE depletionis characteristic of convergent margin lavas (e.g., Pearce and Peate,1995). Fariman basaltic lavas have high La(n)/Yb(n) (7.3–11.7) andLILEs and lack Nb depletion. On this basis we conclude that they areOIB-like (Fig. 10D).

Mashhad gabbros contain 16.2–17.8 wt.% Al2O3 and 47.9–48.2 wt.%SiO2. Their low TiO2 content (0.8 wt.%) is similar to arc-related rocks(Thirlwall et al., 1994). On plots of Na2O + K2O versus SiO2 and MgO(anhydrous-basis; modified after LeBas, 2000), Mashhad gabbros havebasaltic characteristics but ultramafic lavas are komatiites (Fig. 9A and

0 5 10 15 20 25 30 35MgO (wt.%)

0

1

2

3

4

5

Na2

O+K

2O

komatiite TiO2<1%picrite

picrobasalt

potassic rocks

nephelinitic andbasanitic rocks

~43<SiO2<~52 wt.%B

Mashhad oph.

Darrehanjir oph.

Fariman oph.

40 45 50 55 60 65 70 750

1

2

3

4

5

SiO2 (wt.%)

FeO

/MgO

t

medium-Fe

high-Fe

low-Fe

Tholeiite

Calc-alkaline

D

minate betweenmafic and ultramafic lavas (komatiites) within the Darrehanjir–Mashhadc rocks. For comparison,fields for the V1 (lower, Geotimes unit) andV2 (upper, Lasail unit)us SiO2 projection (volatile free, normalized to 100% total) for the Darrehanjir–Mashhadbetween low-, medium-, and high-Fe suites (thick, dashed lines) are from Miyashiro

(komatiite)

(komatiite)

Sam

ple/

Cho

ndrit

e

Sam

ple/

N-M

OR

B

0.01

0.1

1

10

100

1000

0.1

1

10

100

0.1

1

10

100

1

10

100

Mashhad

Rb Th Nb La Pb Sr Zr Sm Ti Tb Ho Tm YbBa U Ta Ce Pr Nd Hf Eu Gd Dy Er Y Lu

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

1000

1

10

100

0.1Darrehanjir

diabasic dike

rodingitized gabbro

ferrodiorite

gabbro/leucogabbro

plagiogranite

1

10

100

1000





basaltic lava

pillow lava

Farimanultramafic lava

gabbro

ultramafic lavas

A B

C D

E F

Fig. 10. Chondrite and N-MORB normalized rare earth and trace element concentrations for the Darrehanjir–Mashhad magmatic rocks.


B). Mashhad komatiites have low SiO2 (38.3–41.5 wt.%) and TiO2 (0.4–0.6 wt.%) contents, but highMg# (77.2–83.1). Their low Ti/V 15.7–21 issimilar to Island-arc tholeiites in Ti vs. V diagram of Shervais (1982)(Fig. 9C). Mashhad gabbros have elevated La(n)/Yb(n) = 2.3–3.1 andare slightly depleted in Nb–Ti and enriched in LILEs (Fig. 10F), similarto calc-alkaline rocks. Ultramafic lavas have low REE contents, butslightly enriched LREEs compared to HREEs (La(n)/Yb(n) = 0.8–1.8)and slight depletion inNb (Nb(n)/La(n)= 0.8–1.1) (Fig. 10F), resemblingmagmas from a SSZ-modified mantle source.

6. Sr–Nd–Pb isotopes

Nd–Sr–Pb isotopic ratios of Aghadarband–Mashhad magmatic rocksare given in Supplementary File 5. The initial 87Sr/86Sr of these rocksvaries between 0.70359 and 0.71011. Such high and variable 87Sr/86Sr

of magmatic rocks could reflect alteration and interaction of the rockswith seawater or contamination by continental crust. Their initial εNdvalues are also variable, between 3.0 and 12.1, and can be divided intohigh (εNd N 10.3) and low values (εNd b 5.4) (Supplementary File 5).These large ranges indicate different sources for the genesis of themelts or contamination by continental crust. On the 87Sr/86Sr vs. εNddiagram, Darrehanjir–Mashhad ophiolitic rocks plot away from Indianand Pacific MORB fields, due to high 87Sr/86Sr (Fig. 11A), but otherwisehave εNd values in the range of age-corrected Pacific and IndianMORBs.

Pb isotopes also show a wide range. Age-corrected 206Pb/204Pb and208Pb/204Pb vary between 16.9 and 20.4 and 37.2 and 38.76 respectively(Supplementary File 5). Most samples have elevated 207Pb/204Pbrelative to the Northern Hemisphere Reference Line (Hart, 1984)(Fig. 11B), ranging from 15.36 to 15.76 except two samples (Darrehanjirgabbro and Fariman pillow lava) that have lower 207Pb/204Pb.

Mashhad ophioliteDarrehanjir ophioliteFariman ophiolite

207

204

(Filled symboles=Komatiite)

87Sr/86Sr (t)

-8

-4

0

4

8

12

εNd

(t)

10 20 50 100

105

106

107

Seawater

Sea water alteration

Subducted sediments

Pacific-N Atlantic MORB

Indian MORB

A

-8

-4

0

4

8

12

206Pb/204Pb (t)

Subducted sediments

Indian MORB


εNd

(t)

Paleo-Tethyan OceanD

15.3

15.4

15.5

15.6

15.7

Pb/

Pb

(t)

NHRL


Indian MORB

Subducted sediments

Paleo-Tethyan Ocean

B

206Pb/204Pb (t)

208

204

36.5

37

37.5

38

38.5

39

39.5

Pb/

Pb

(t)

NHRL


Indian MORB

Subducted sediments

Paleo-Tethyan Ocean

C

0.702 0.704 0.706 0.708

16 16.5 17 17.5 18 18.5 19 19.5 20

16 16.5 17 17.5 18 18.5 19 19.5 20

16 16.5 17 17.5 18 18.5 19 19.5 20206Pb/204Pb (t)

Fig. 11.Age-corrected εNdvs. 87Sr/86Sr (A), 207Pb/204Pb vs. 206Pb/204Pb (B), 208Pb/204Pb vs. 206Pb/204Pb (C) and εNd vs. 206Pb/204Pb ratios (D) for theDarrehanjir–Mashhadmagmatic rocks.The solid line in εNd vs. 87Sr/86Sr diagram shows the effect of seawater alteration on the Sr and Nd isotope composition of rocks for different water/rock interactions.Modified after Liu et al. (2013).


Aghadarband–Mashhad magmatic rocks also plot above the NorthernHemisphere Reference Line on 208Pb/204Pb–206Pb/204Pb diagrams(Fig. 11C), The highest 207Pb/204Pb and 208Pb/204Pb values indicate the in-volvement of subducted terrigenous sediments in the source. Theplagiogranitic dike has very high 207Pb/204Pb and 206Pb/204Pb (Fig. 11B),perhaps due to contamination by continental crust. Komatiites have var-iable Sr and Nd isotopes but similar Pb isotopic values. The Darrehanjir–Mashhad magmatic rocks have both high εNd and low εNd for givenlow 206Pb/204Pb, except plagiogranitic dike with high 206Pb/204Pb(Fig. 11D).

7. U–Pb dating and zircon O–Hf isotopes

7.1. U–Pb zircon ages

We tried to date three samples from Darrehanjir including gabbro(DA12–22), ferrodiorite (DA12–19) and a plagiogranitic dike (DA12–8) that intrudes host gabbros. Gabbroic samples (DA12–22) did nothave enough zircons and no meaningful age was obtained.

Zircons from sample DA12–8 (plagiogranitic dike) have broken-anhedral shapes. Most are fine-grained (N50 μm long). In CL images,most grains are weakly zoned. Core and rim structures are absent.A total of 21 spot analyses were carried out on this sample (Supple-mentary File 6). The zircons have high U (2181–7446 ppm) and Th(108–1034 ppm) contents, resulting in low Th/U (0.04–0.15). CommonPb contents are low, with f206 (the proportion of common 206Pb in totalmeasured 206Pb) b 1.0% except for spots 1 and 6. 206Pb/238U ages rangefrom ~192 to 393 Ma (Supplementary File 6). On an inverse U–Pbconcordia diagram (207Pb/206Pb vs. 238U/206Pb; Fig. 12 A and B), most

analyses are concordant within analytical errors. The younger discor-dant ages may reflect metamorphism and Pb loss. The best analyseshave weighted mean age of 380.6 ± 3.7 Ma (MSWD = 0.45)(Fig. 12 B), interpreted as reflecting the time of zircon crystallization.

Zircons from sample DA12–19 (ferrodiorite) are transparent tosemi-transparent, 50 to 120 μm long. In CL images, zircons are charac-terized by broad and/or magmatic concentric zoning. Sixteen analyseswere conducted on zircons from this sample. The zircons havemoderate(147–562 ppm) to high (830–3981) U and Th (45–990) contents withTh/U ratios between 0.15 and 1.2 (Supplementary File 6). Commonlead is variable with f206 ranging from 0.03 and 1.6. The common206Pb/238U and 207Pb/206Pb define a concordia to discordia on the in-verse (Tera–Wasserburg) U–Pb concordia plot (Fig. 12C) with an inter-cept age of 382.9 ± 3.7 (MSWD = 1.7). This is interpreted as the bestage of ferrodiorite crystallization.

7.2. In situ zircon O–Hf isotopes

In situO isotopicmeasurementswere conducted on fourteen zirconsfrom the plagiogranitic dike (Supplementary File 7). The measuredδ18Ozircon values are variably low, from 1.8‰ to 6.6‰. Low values ofδ18Ozircon could be due to the hydrothermal alteration of plagiograniticsample (Li et al., 2013), or reflect magmas generated by meltinghydrothermally-altered crust (Moani and Valley, 2001). The δ18Ozircon

values higher than 5‰ are likely magmatic values as they are similarto igneous zircons fromMid-Atlantic and Southwest IndianRidge gabbrosand plagiogranites (5.3 ± 0.8‰; Cavosie et al., 2009 and 5.2 ± 0.5‰;Grimes et al., 2011) and from Western Alps ophiolitic albitites andgabbros (5.4 ± 0.4‰; Li et al., 2013). The ferrodiorite sample has

0.0505

0.0515

0.0525

0.0535

0.0545

0.055

0.065

238U/206Pb

207 P

b/20

6 Pb

240

280

320

360

400

440

Intercepts at109±40 & 376±11Ma

MSWD=0.46

Sample DA12-8 (plagiogranite)Concordia age=380.6±3.7MaMSWD (of concordance)=0.45

0.052

0.053

0.054

0.055

0.056

238U/206Pb

370

390

410

Concordia age = 380.6 ±3.7 MaMSWD (of concordance) = 0.45Probability (of concordance) = 0.50

Sample DA12-8 (plagiogranite)

0.048

0.050

0.052

0.054

0.056

380

0.058

12 16 20 24 28 32 15 15.4 15.8 16.2 16.6 17 17.4 17.8

14 15 16 17 18 19

207 P

b/20

6 Pb

238U/206Pb

340

420

Sample DA12-19 (ferrodiorite)Concordia Age = 382.9 ±3.7 MaMSWD (of concordance) = 1.7

@9

@10

390.7

373.7

@15

@13378.7

376.6

@4 @5396.5

389.6 @10

@9376.0

374.4

DA12-8

DA12-8

DA12-19DA12-19

A B

C D

Fig. 12. U–Pb inverse concordia diagrams for zircons from plagiogranitic dike and ferrodiorite from the Darrehanjir–Mashhad ophiolites.

εHf (

t) 0

10

20

-10

-20

-30

Depleted mantle

CHUR

1.85 Ga

3.4 Ga

3.8 Ga176 Lu/1

77 Hf=0.015

PlagiograniteFerrodiorite

A


δ18Ozircon values ranging from 3.7‰ to 6.5‰ (Supplementary File 7) witha mean δ18Ozircon value of 4.6 ± 0.3‰ (except low and high values of 3.7and 6.5‰) (Fig. 13B).

Plagiogranite zircons have fairly homogeneous initial 176Hf/177Hfwith an average of 0.282960 ± 0.000037. Their εHf(t) variesfrom +11.7 to +19 (Supplementary File 7; Fig. 13A); with meanvalue of +14.9. The ferrodiorite zircons have 176Hf/177Hf between0.0282869 and 0.282977 with mean value of 0.282922 ± 0.000020(Supplementary File 7). The measured 176Hf/177Hf values correspondto εHf(t) = +12 to +15.8 (mean εHf(t) = +13.8) (Fig. 13A).

Similar U–Pb zircon ages, δ18O, and εHf support the interpretationthat ferrodiorite and plagiogranite are comagmatic.

U/Pb Age (Ma)0 500 1000 1500 2000 2500 3000

8

12

uenc

y

Plagiogranite Ferrodiorite

B

8. Discussion

Below we consider the implications of our new data for under-standing three aspects of the Darrehanjir–Mashhad mafic–ultramaficcomplex: 1) Implications of age constraints for understandingpetrogenesis; 2) similarity to other Paleozoic ophiolites in Asia;and 3) tectonic implications.

0

4

Freq

δ O18 (zircon)1 2 3 4 5 6 7

Fig. 13. A — U–Pb age vs. εHf for zircons from the Aghdarband plagiogranitic dike andferrodiorite. Histograms show the zircon Hf model ages (B) and δ18Ozircon (C) for theplagiogranitic dike and ferrodiorite.

8.1. Implications of age constraints for understanding petrogenesis

The ~100 Ma difference between our new Devonian ages forDarrehanjir plagiogranite and ferrodiorite and established Permian ra-diometric and biostratigraphic ages for other rocks of the Darrehanjir–Mashhad mafic–ultramafic complex compels the conclusion that thisis not a single ophiolite but composite igneous complex with compo-nents that formed ~100 Ma apart, in Devonian and Permian times.This provides new understanding of the rocks of this complex,


explaining for example the puzzling co-existence of undepletedlherzolites and komatiitic lavas, which are very high-degree melts.

8.1.1. Devonian mantle-crustal remnants (Darrehanjir complex)A variety of observations about the Darrehanjir lherzolite, including

low Cr# spinels and highNa2O and TiO2 contents of these clinopyroxenessuggest that these peridotites are relatively undepleted. Igneous rocks ofDevonian and Permian episodes have different geochemical signatures.Devonian SSZ-type magmatism may reflect subduction initiation withinthe Paleo-Tethyswith formationof boninitic to calc-alkaline-like gabbros;diorites and plagiogranites and/or related to arc volcanism at the foot ofsouthern margin of Eurasia. Our data show that the Darrehanjir gabbrosare depleted in HFSEs and bulk REE, resembling boninites. Gabbroclinopyroxenes have low TiO2 contents resembling those of arc tholeiites(Fig. 6).

The difference in the trace element composition of the mantlesources of the Darrehanjir–Mashhad ophiolitic samples can be exam-ined using Th/Yb vs. Nb/Y and Nb/Y and Zr/Y diagrams (Fig. 14A andB). For comparison we also plotted data from other Iranian Paleozoicophiolites (Fig. 1). The data used for comparison are: 1) the RashtMiddle Carboniferous eclogites (with basaltic protolith) and gabbros(with SSZ signature) (Zanchetta et al., 2009) and 2) Devonian to Perm-ian metagabbro and metabasalt of the Jandagh–Anarak ophiolite withSSZ geochemical affinity and minor MORB-type lavas (Buchs et al.,2013). Metabasites in the Jandagh–Anarak ophiolites define six petro-genetic groups including: 1) N-MORB like basalts; 2) E-MORB likerocks; 3) BABB-like lavas; 4) calc-alkaline-type rocks; 5) OIB-type ba-salts, considered as remnants of intraplate oceanic volcanism and6) boninites (Bagheri and Stampfli, 2008; Buchs et al., 2013). Th/Yband Nb/Yb are good tracers of mantle source composition becausethese ratios are largely independent of the extent of partial meltingand crystal fractionation. Th can also be considered as a tracer ofsubducted marine sediments or contamination by continental crust(Plank and Langmuir, 1998). Therefore Nb/Yb represents the degree ofmantle enrichment and/or depletion whereas Th/Yb reflects sedimentscontribution (Pearce and Peate, 1995). Nb/Y varies similar to Nb/Yb andreflects mantle enrichment whereas Zr/Y is sensitive to SSZmagmatismas Y and other HREEs are depleted in arc lavas. Of course the Zr/Y ratio isstrongly affected when zircon forms and fractionates. Most Darrehanjirrocks have high Th/Yb for a given Nb/Yb, plotting above the mantlearray, indicating addition of melt/fluids from subducted sediments orcontinental crust contamination (Fig. 14A).

8.1.2. Permian arc-related rocks (Fariman–Mashhad complex)In contrast to Devonian igneous rocks, Permian magmatism was

compositionally variable; changing from the Nb-depleted, SSZ-relatedMashhad and Fariman komatiites to calc-alkaline Mashhad gabbros.

Zr/Y0.1 1

0.01

0.1

1

10

Plume a

rray

MORB &

Nb/

Y

Mashhad ophiolite (this study)

Far. ophiolite (Z. et al. 2013)

Dar. ophiolite (Z. et al. 2013)

Fariman ophiolite (this study)

0.1 1 10 100Nb/Yb

0.01

0.1

1

10

100

MORB-OIB array

volcanic arc array

Th/Y

b

J-A

op

hio

lites

N-MORB

E-MORB

OIB

Darrehanjir ophiolite (this study)

Oman V2 lavas

AOIBtholeiite-boninite

BABB

B. &

S.,

2008

group 5bgroup 5agroup 4group 3group 2group 1

Buch

s et

al.,

201

3

Rasht ophiolite (Z. et al., 2009)

Oman V1 lavas

Fig. 14. Trace element compositional variations of the Darrehanjir–Mashhad ophiolites. For co(A) Th/Yb vs. Nb/Yb and (B) Nb/Y vs. Zr/Y diagrams. Th/Yb vs. Nb/Yb diagram is from Pearce (Godard et al. (2003) and on Izu–Bonin–Mariana (IBM) forearc from Reagan et al. (2010). Data o(2008); on Rasht ophiolites from Zanchetta et al. (2009) and on Darrehanjir–Mashhad ophioliDarrehanjir–Mashhad magmatic rocks. Although the Darrehanjir–Mashhad magmatic rocksand sediment components. The mantle wedge end-member is very depleted-Indian MORB mafter Liu et al., 2013).

Clinopyroxene from the Permian Fariman–Mashhad SSZ-type lavas re-sembles those of back-arc basin basalts and MORBs, while lava spinelslook like those of island-arc tholeiites (Fig. 7). Fariman pillowed andmassive lavas also have compositions that are transitional betweencalc-alkaline and E-MORB-type rocks (pillow lavas) and OIB-like (mas-sive lavas) lavas. Permian komatiites are different than any other arc-related lava and it is hard to convincingly assign these to a tectonicsetting. Clinopyroxenes from the Fariman OIB-type lavas have veryhigh TiO2 contents (Fig. 6). The combination of komatiitic lava and OIBsuggests the role of a mantle plume. As these lavas are interbeddedwith pelagic and turbiditic sediments, they clearly formed in a subma-rine environment. Intra-arc splitting and magmatism and/or continen-tal back-arc magmatism are also considered for the genesis of thePermian, geochemically diverse lavas associated with pelagic/terrige-nous sediment deposition (Zanchetta et al., 2013).

Fariman Permian lavas have Th/Yb that plot within the enrichedMORB mantle array, suggesting a slightly enriched mantle source andlittle subduction influence, similar to what might be produced bya mantle plume (Fig. 14A). Mashhad igneous rocks plot betweenDarrehanjir high Th/Nb rocks and Fariman low Th/Nb rocks. Forcomparison, most magmatic rocks from the Jandagh–Anarak, Rasht,Mashhad and Aghdarband ophiolites appear to be subduction-related.OIB-like lavas are common in the Darrehanjir–Mashhad and Jandagh–Anarak ophiolites, but the Jandagh–Anarak lavas are represented byhigher Nb/Y ratio, representing plume array (Fig. 14B).

8.1.3. Origin of komatiitesPhanerozoic komatiitic lavas are very unusual and could only be

generated by extensive melting of a peridotite source. We expect thatextremely depleted harzburgite and dunite would remain as residue,and for this reason the Darrehanjir–Mashhad Permian komatiites can-not have been generated by melting of undepleted Darrehanjir perido-tites. Given the geochronological constraints, it makesmuchmore sensethat these melts and residues were produced by two distinct magmaticepisodes, a Devonian episode involving modest mantle melting leavinglherzolite residue followed 100Ma later by a Permian episode of unusu-ally intense mantle melting to generate komatiites.

We note strong affinities of Permian Fariman–Mashhad komatiitesand basalts with other Permian plume-related igneous sequences inAsia. The Permian was a time when repeated mantle plumes impactedAsia, including Tarim (~270–280 Ma; Zhang et al., 2010, 2011; Yuet al., 2011), Emeishan (~260 Ma; He et al., 2007) and the ~250 MaSiberian Traps (Reichow et al., 2009). We note with interest that thePermian LIP that is closest in age to Mashhad–Fariman (281–287 Ma)is Tarim (270–280 Ma), which is also located nearest to Iran. Thekomatiites and basalts of Fariman–Mashhad could be another manifes-tation of Permian mantle unrest. In the Karakoram region, along the

10

SSZ ro

cks

IBM forearc basalts

IBM boninite

B

0 0.1 0.2 0.3 0.4 0.5Th/Nb

0.5118

0.5120

0.5122

0.5124

0.5126

0.5128C

+ ++

++

++

++

+

++

++++

+

+

++

+++

+

0.5%

1%

2%

3%

5%7%10%

20%

1%1%

2%

2%

3%

3%

5%5%

7%7%

10%10%

20%20%

Subductedsediments Sediment melt

UnradiogenicPb sedimentsGloss

UnradiogenicPb sediments

DIMM

Indian MORB

Pacific MORB

143 N

d/14

4 Nd

mparison we plotted also data on the other Iranian Paleozoic ophiolitic magmatic rocks.2008) and Nb/Y vs. Zr/Y diagram from Fitton et al. (1997). Data on Oman ophiolites fromn the Jandagh–Anarak (J–A) ophiolites from Buchs et al. (2013) and Bagheri and Stampflites from this study and Zanchetta et al. (2013). C — Plot of Th/Nd vs. 143Nd/144Nd for theare dispersed in this diagram, most of them form a binary array between mantle wedgeantle (DIMM; Stracke et al., 2003) with high 143Nd/144Nd but low Th/Nd ratios (modified


southernmargin of Eurasia, high-Mgkomatiitic and basaltic pillow lavaswithout spinifex texture are also present within Permian–Triassicargillitic-carbonated sediments (Rao and Rai, 2007) and are geochemical-ly and geodynamically similar to Mashhad–Fariman komatiites. PanjalTraps of northern India (289 Ma) may also part of this Late Permian“plume-related” group, although komatiites are not found (Shellnuttet al., 2014).

Different origins are suggested for generating komatiitic magmasincluding 1) partial melting of dry peridotites (e.g., Arndt et al., 1998)and 2)wet and shallowmelting of hot, depleted peridotites in theman-tle wedge above a subduction zone (e.g., Grove and Parman, 2004). Thesecond type of komatiitic lavas is geochemically related to boninites.The high Mg# of the Mashhad–Fariman komatiitic rocks and the highmelt temperature required for the generation of this type of magmasuggest Permian mantle plume activity in the region.

8.1.4. Isotopic signature of the Darrehanjir–Mashhad ophiolitesAs the hydrothermal alteration of oceanic crust raises the 87Sr/86Sr of

the altered oceanic rocks (e.g., McCulloch et al., 1981; Godard et al.,2006), the high 87Sr/86Sr ratios of the Darrehanjir–Mashhad rocks arenot thought to be magmatic Sr isotope compositions. In contrast, Nd isrelatively immobile in fluids unless the water/rock ratio reaches N105

during alteration (Faure and Mensing, 2004) so the 143Nd/144Nd ratiosof the studied rocks probably were not influenced by seawater alter-ation. U and Pb mobility during hydrothermal alteration can influencethe Pb isotopic composition of the affected rocks (Faure and Mensing,2004); specifically U addition during alteration could increase 206Pb/204Pb with time. Because Th is immobile during alteration and alsobecause of low abundance of 235U, 207Pb/204Pb and 208Pb/204Pb ratiosof the igneous rocks should reflect those of their mantle source (Hauffet al., 2003; Liu et al., 2013). Therefore it seems that Pb and Nd isotopevalues of our rock samples reflect source characteristics and not alter-ation. The Nd and Pb isotopic signature of the Darrehanjir–Mashhadmagmatic rocks is unlikely to reflect subducted sediments or continen-tal crust contamination into a depleted mantle source. To infer the sed-imentmelt contribution to a depletedmantle source of theDarrehanjir–Mashhad magmatic rocks, we used Th/Nd vs. 143Nd/144Nd modeled byLiu et al. (2013) (Fig. 14C). Th and Nd are immobile in fluids releasedfrom subducted oceanic crust and overlying sediments but are mobilein sediment melts (Johnson and Plank, 1999; Liu et al., 2013). Althoughthe samples are dispersed in this diagram, some data define a lineartrend between mantle wedge (depleted Indian MORB mantle) andsediment (least radiogenic Pb Izu–Bonin sediments; Plank et al., 2007)end members (Fig. 14C). The Mashhad and Fariman komatiites havehigh 143Nd/144Nd suggesting a highly depleted mantle source withoutsubducted sediment contributions.

As the δ18Ozircon values are relatively insensitive to magmatic differ-entiation (Valley, 2003; Valley et al., 2005), but quite sensitive to alter-ation (Li et al., 2013), the low δ18Ozircon values for ferrodiorite (δ18Ozircon

~ 4.6 ± 0.3‰) zircons indicate crystallization from magmas inequilibrium with depleted mantle. In contrast, the variable δ18Ozircon

of plagiogranite zircons (2.6 to 6.6‰) suggests contributions fromhydrothermally altered materials such as amphibolites. Furthermore,the highly positive and similar εHf(t) = +14.9 (for plagiogranite)and +13.8 (for ferrodiorite), further indicate both derivation ofmagma from depleted mantle and that ferrodiorite and plagiograniteare broadly co-genetic. We further infer from variably low δ18Ozircon

that both ferrodiorite and plagiogranite magmagenesis may have in-volved hydrothermally altered rocks.

8.2. Comparison with other Asian Paleozoic ophiolites

The Central Asian Orogenic Belt (CAOB) is one of the largestaccretionary orogeny belt in the world, characterized by long-lived ac-cretionary orogenesis and containing many Paleozoic ophiolite slices(e.g., Windley et al., 2007; Maruyama et al., 2010). The Paleo-Tethys

belt that the Devonian–Permian Darrehanjir–Mashhad complex be-longs represents another Paleozoic ocean basin that may be related tothe CAOB. Below we summarize the ophiolites and related rocks ofthis SW branch of Paleo-Tethys.

The Tavric (Caucasus)–Kura (Turkey) mélange along the southernboundary of the Scythian domain contains turbidites with exotic blocksof Carboniferous–Permian pelagic limestones (e.g., Sengor et al., 1988;Zonenshain et al., 1990; Ustaomer and Robertson, 1993), suggestingPaleo-Tethys extended as far west as Turkey.

The Transcaucasian massif, situated between the Great Caucasus tothe north and the Lesser Caucasus to the south (Zakariadze et al.,2007), contains traces of Early Paleozoic metamorphosed ophioliticrocks including sheeted dikes and pillow lavas (Gamkrelidze et al.,1999; Rolland et al., 2011). A tectonic mélange zone, to the north ofthe Sevan–Akera Suture including allochthonous slices of middlePaleozoic rocks (serpentinites, amphibolites, phyllites, granites andhigh-silica volcanic rocks) was affected by early Variscan metamor-phism based on Ar–Ar dating (330–336 Ma; Zakariadze et al., 2007;Treloar et al., 2009). These rocks may reflect an accretionary prismwith slices of oceanic lithosphere and continental arc-related volcano-sedimentary units at the foot of the Eurasian margin. These units aresimilar to Ocean Plate Stratigraphy (OPS) of Kusky et al. (2013) withlater exhumation of HP metamorphic rocks and post-accretion graniticmagmatism.

The Turkman zone in Turkmenistan (Boulin, 1980, 1988) is markedby Early Paleozoic to Late Devonian deep oceanic sediments andophiolites (Fig. 15). North–northwest of the Aghdarband region, inKizilkaya and Tuar regions of Turkmenistan, there are outcrops of oce-anic crust including 200 m thick cherty slates and 100 m thick pyroxe-nite, gabbro diabase and pillow lava intercalated with Early to MiddleCarboniferous radiolarites (Mirsakhanov, 1989). The mafic rocks arelow-TiO2 basalts to basaltic andesites considered to have formed in aSSZ environment such as a back-arc basin (Garzanti and Gaetani, 2002).Permian rocks of the Tuarkyr complex (northwest of Aghdarband) arerepresented by continental and shallow marine volcaniclastic rockswith interbedded pyroclastic deposits, interpreted to represent a conti-nental magmatic arc (Garzanti and Gaetani, 2002). This is consistentwith that described in the Permian volcano-sedimentary sequence ofthe Aghdarband region by Zanchetta et al. (2013).

Early Paleozoic to Late Devonian rock units in Afghanistan includeflysch of Cambrian–Ordovician to Silurian age (Boulin, 1988) that mayreflect pulses of Paleo-Tethys propagation. Devonian pelagic sedimentsassociated with gabbro, serpentinite and volcanic rocks are commonalong the Herat–Akbaytal Fault (Boulin, 1988), which also marks a Pa-leozoic suture. The Lower Carboniferous volcano-sedimentary rocks as-sociated with calc-alkaline lavas and shallow-marine, fossil-bearinglimestones in northeast Afghanistan (in western Hindu Kush andBadakhshan regions; Boulin, 1988) may reflect this phase of active con-tinental margin magmatism.

The Tibetan plateau also preserves Paleo-Tethys oceanic remnantsand subsequent amalgamation between the Laurasia andGondwana su-percontinents since the Paleozoic (Sengor and Natalin, 1996; Zhai et al.,2013). Recent observations from eclogites (with MORB protolith; Yanget al., 2009) and U–Pb dating of OIB-type gabbros (Dai et al., 2011)define a Devonian to Carboniferous–Permian suture zone (NorthGangdese suture zone; Yang et al., 2009). Further to the east, pillowlavas fromnorth–northeast Tadjikistan have pelagic limestones interca-lated with Famennian–Tournaisian (ca. 360 Ma) ages and show a traceof back-arc oceanic crust (Jiang et al., 1992). Subduction of Paleo-Tethyslithosphere in this region started from middle Paleozoic time, mainlyduring the Devonian (Sengor and Natalin, 1996; Schwab et al., 2004).

Although the subduction polarity of oceanic crust withinthe CAOB is controversial, an important feature is a dominantnorthward subduction polarity of numerous Neoproterozoic–Paleozoic subduction zones surrounding the Laurasian continentalblocks (Safonova and Maruyama, 2014; Safonova and Santosh, 2014;

Paleozoic Ophiolites

+

Dar

reha

njir

430 Ma

380 Ma

330 Ma

280 Ma

230 Ma

480 Ma

Kashafrud Formation

Qara-Gheitan Formation

sediments

Mas

hhad

-Far

iman

Interbedded

Hornblende gabbro

Ar-Ar ages

Mashhad turbidites

+

Mashhad granites

Rash

t-Sh

ande

rman

Eclogites

Shemshak Formation

Jand

agh-

Ana

rak

+U-Pb zircon agesJandagh granites

+

U-Pb zircon ages

Anarak trondhjemites

+++

Granitic pebbles inQara-Gheitan Formation++

+Z

K

+++ +

Granitic pebblesin Kashafrud F.

+++ +

Torbatejamgranites

Turk

men

ista

n

Afg

hani

stan

Cau

casu

s

180 Ma

Ordovician

Devonian

Carboniferous

Permian

Triassic

Paleotethys opening

East

ern

Alb

orz

+

+

pelagic-terrigenous

Plagiogranite/Ferrodiorite

diorite

N o

f Dam

ghan

+

+

+

+

+

Non-ophiolitic rocks

Ophiolitic rocks

~

~ Rb-Sr ages

+ Ar-Ar or K-Ar ages

Tuarkyr radiolarites

Shanderman phyllites

+

Radiolaritesassociated with lavasand gabbros

deep oceanic sedimentsassociated with oceanic lithosphere

++

++

+

Doab-Salang-Chaidangranodiorites

+accretionary prism rocks

HT met. rocks

Collision?lavas

Subduction initiation & ophiolite formation

continental arc magmatism& arc unroofing

Fig. 15. Simplified chart showing the ages of magmatic and sedimentary sequences that constrain ages of Iranian Paleozoic ophiolites; greenish area inside dashed lines encompassesophiolite ages. U–Pb dating of granitic pebble from Qara–Gheitan Formation (K) from Karimpour et al. (2011), Ar–Ar age data on the Mashhad ophiolites from Ghazi et al. (2001),U–Pb zircon ages on the Mashhad granites from Karimpour et al. (2010) and Mirnejad et al. (2013), Ar–Ar ages on the Rasht–Shanderman eclogites from Zanchetta et al. (2009), U–Pbzircon age data on the Anarak trondhjemites and Jandagh granites from Bagheri and Stampfli (2008), U–Pb zircon data on the Torbat-e-Jam granites, granitic pebble from Qara–GheitanFormation (Z) and granitic pebbles from Kashafrud Formation from Zanchetta et al. (2013). Ar–Ar ages on the Caucasus accretionary prism and high-T metamorphic rocks are fromRolland et al. (2011); data on the Turkmenistan and Afghanistan pelagic sediments are from Garzanti and Gaetani (2002), Zakariadze et al. (2007), Treloar et al. (2009) and Boulin(1988) respectively.


Xiao et al., 2012). The Late Carboniferous–Early Permian calc-alkalineintrusions and volcanism in the Mediterranean and Caucasus regionsalso reflect northward subduction of Paleo-Tethys beneath Eurasia(Stampfli and Borel, 2002; Rolland et al., 2011). High temperature-lowpressure metamorphic rocks in southern Georgia with Ar–Ar age of303 Ma (Carboniferous, Rolland et al., 2011) and high-pressure rocksin northern Iran (Shanderman Complex in the Rasht ophiolite;Omrani et al., 2013) with an Ar–Ar age of 330 Ma (Zanchetta et al.,2009) are interpreted as Paleo-Tethys subduction channels.

Although northward subduction dominated the CAOB, local oppo-site subduction polarities related to collision of microcontinental blockswere also common. Southward subduction beneath the North Tianshanarc (SE Kazakhstan, within CAOB) was responsible for generating ca.343 Ma SSZ-type plagiogranites and ca. 302 Ma E-MORB (and OIB-like) gabbros (Li et al., 2014). The Carboniferous Kunlun arc in thenorthern Pamirs and northwestern Tibet along with magmatism inTadjikistan is related to north-facing subduction (Schwab et al., 2004).Debates about CAOB subduction polarities continue but this does notchange the conclusion of mostly northward subduction in the CAOB(Safonova and Maruyama, 2014).

The fertile lherzolites and pyroxenites at Darrehanjir suggest a rem-nant of oceanic lithosphere, but Devonian magmatic rocks may reflectarc magmatism along the southern margin of Eurasia and/or at anintra-oceanic infant arc. TheMid-Paleozoic to EarlyMesozoic ophiolites,

accretionary complexes and forearc sequences could indicate a long-lived subduction system (Domeier and Torsvik, 2014). We suggestthat the fertile peridotites and Darrehanjir Devonian SSZ-typemagmat-ic rocks probably reflect incipient forearc lithosphere, generated alongthe southern margin of Eurasia in Early Devonian time and thenoffscraped with arc-related Permian magmatic rocks in an accretionarycomplex.

8.3. Tectonic implications

The most prominent pulse of Iranian ophiolite formation duringEarly to Middle Paleozoic time coincided with episodes of rifting alongthe northern margin of Gondwana and the northward drift of thesefragments (Fig. 16). Despite different interpretations for the formationand emplacement of the Permian oceanic fragments in northeast(Mashhad, Fariman and Darrehanjir) and central (Jandagh–Anarak)Iran, we believe that these also represent Paleo-Tethys oceanic litho-sphere. The Iranian geologic record suggests that Paleo-Tethys startedto open as early as Ordovician time (Stampfli, 1978; Stampfli et al.,1991) with subduction beginning by 380Ma (Fig. 15). Subduction initi-ation along the southern margin of Eurasia may have been diachronousas Turkmenistan and Caucasus ophiolites represent Carboniferous SSZ-type oceanic crust. Zanchetta et al. (2013) concluded that Paleozoicvolcano-sedimentary units around Fariman and Darrehanjir were


deposited during Permian time. This included siliciclastic turbidites de-rived from the erosion of a magmatic arc and its basement,interfingered with carbonates and basaltic lava flows with calc-alkalineand transitional (alkaline) affinities. In this view, the Fariman–Darrehanjir igneous rocks developed as remnants of a magmatic arc atthe southern margin of Eurasia, above the north-dipping Paleo-Tethyssubduction zone, with Fariman and Darrehanjir complexes originatingvia spreading in an intra-arc or incipient back-arc basin along the south-ern margin of the Turan domain (Zanchetta et al., 2013), which was anactive margin since at least Carboniferous time (Zanchetta et al., 2013).According to our new field, geochemical, and U–Pb age data, the occur-rence of peridotites with dunite screens and clinopyroxenitic dikeswith mineralogy and geochemistry similar to those in abyssal perido-tites associated with Devonian boninitic to calc-alkaline gabbros/plagiogranites supports an interpretation of formation in a marginalbasin or subduction–initiation forearc. Intra-oceanic subduction initia-tion in Early/Late Devonian time also occurred about the same time asformation of Nakhlak boninites in the Jandagh–Anarak ophiolites ofcentral Iran (Bagheri and Stampfli, 2008). The volcaniclastic sedimentscould have been fed from the Silk Road continental magmatic arc.On the other hand, our new U–Pb zircon data demonstrate a pulse ofSSZ-type oceanic crust formation during Early Late Devonian time(Fig. 16). In this scenario, Permian magmatism and associated terrige-nous/pelagic sediments could representmagmatism and sedimentationin a subduction-related basin at the foot of the Eurasia margin, re-sembling an accretionary orogenwith fragmented, Devonian oceaniccrust and then subsequent Permian magmatism. In this scenario, thePermian–Triassic closure of the Paleo-Tethys built an accretionarywedge, incorporating Devonian SSZ-type oceanic lithosphere. Accre-tionary orogens develop at sites of oceanic lithosphere subduction

OIB-like lavas fromJandagh-Anarak

Gondwana Hunic terranes

subduction initiationearly arc volcanism

Gondwana Hunic terranes

SSZ and MORB-like lavasintercalated with turbiditic sediments

NESW

Rheic Ocean

Gondwana

arc volcanism

PaleotethysEarly MORB

Rift volcanism

Asiatic Hunic terranes

A

B

C

volcanismarc

Fig. 16. Schematic model for the formation and evolution of Iranian Paleozoic ophiolites(modified after Shafaii Moghadam and Stern, 2014). A) Continental rifting and openingof the Paleo-Tethys Ocean in Late Ordovician to Silurian time. B) Subduction initiation inMiddle to Late Devonian and formation of boninites and gabbros from the Nakhlak andDarrehanjir ophiolites. C) Formation of intra-oceanic and continental margin arcvolcanism and then arc unroofing in Carboniferous to Permian time with occurrence ofarc-like and MORB-like lavas in Fariman–Darrehanjir ophiolites.

and are characterized by time-integrated tectonic elements includingaccretionarywedges, oceanic crust (ophiolite), andmaterials offscrapedfrom the subducting slab, including OIB and komatiitic lavas alongwithpelagic sediments (Kusky et al., 2013). The amalgamation of these rockunits occurred at different times and was accompanied by graniticmagmatism (Safonova et al., 2011). Final collision between Cimmeriaand Eurasia is generally thought to have occurred in Triassic time, butLate Triassic–Early Jurassic time is also considered for Paleo-Tethysclosure followed by Middle Jurassic post-collisional rifting anddeposition of Kashafrud Formation (Robert et al., 2014).

Granitic–granodioritic intrusions into the Mashhad–Torbat-e-Jamophiolites yield U–Pb zircon ages of 215±4 and 217±4Ma (Karimpouret al., 2010) and 199.8 ± 3.7 and 217 ± 4 Ma (Mirnejad et al., 2013;Zanchetta et al., 2013). We take these Late Triassic ages to approximatewhen these plutons intruded the already-obducted ophiolites. Thisinterpretation is supported by the fact that cobbles of these granitesare found in the basal conglomerate of the Middle Jurassic KashafrudFormation near Mashhad (Shafaii Moghadam and Stern, 2014).

The presence of early S-type granites with metamorphic enclaves,geochemical signatures as well as Sr–Nd isotopes (Karimpour et al.,2010; Mirnejad et al., 2013; and our unpublished data) shows that theMashhad granitoids have post-collisional characteristics, producedfrom re-melting of continental crust. According to paleogeographic re-constructions proposed by Angiolini et al. (2007) and Muttoni et al.(2009), Iranian Cimmeria rifted away from Gondwana at the end ofLower Permian time and collided with southern Eurasia in the LateTriassic. Others argue that northward subduction of Paleo-Tethysoceanic lithosphere began along the southern Eurasia margin in Mid- toLate Paleozoic time (e.g., Alavi, 1991; Ruttner, 1993; Metcalfe, 2006;Zanchi et al., 2009) Fig. 17 at least in Turkey, Caucasus, Iran andAfghanistan.

On the other hand, the direction of duplexing of accreting OceanPlate Stratigraphyunits is also another factor for understanding the sub-duction polarity within old accretionary orogens (e.g., Maruyama et al.,2010; Safonova and Maruyama, 2014). Although the orientation of thestructureswithin theKopet–Daghbelt is related to theAlpine reactivationof the Paleozoic basement structures (Robert et al., 2014), most thrustfaults involving basement show a northward polarity for subduction.

Late Paleozoic and Early Triassic subduction-related magmaticrecords in the southern Turan block can be correlated to similar onesin the West Kunlun (Xiao et al., 2005). It seems that Alai–Tarim blockswere micro-continents separating the main Paleo-Asian Ocean and itsbranches, the Turkestan or South Tienshan and Junggar–Balkash oceans(Windley et al., 2007) located to the north (present-day coordinates),from the southern Paleo-Tethys Ocean branch to the south (Xiao et al.,2005, 2013).

9. Conclusions

Considering all field, geochemical, isotopic as well as U–Pb zirconage data on the Paleozoic Mashhad–Darrehanjir ophiolites lets usconclude that:

1. Darrehanjir–Mashhad mafic–ultramafic complex is not a singleophiolite but a composite igneous complex composed of Permianpillow lavas and pelagic sediments in fault contact with a small out-crop of Devonian intrusive and ultramafic rocks around Darrehanjir.

2. Our new SIMS U–Pb zircon dating results demonstrate thatDarrehanjir ophiolite gabbroic rocks and their fractionated products(plagiogranitic dike) crystallized synchronously at ~380–382 Ma.The crystallization age of Darrehanjir gabbros differs from theMash-had gabbroswith ages of ~282–288Ma. These new ages confirm thatDarrehanjir plutonic rocks are ~100 Ma older than published Ar–Arand biostratigraphic ages for gabbros and radiolarites intercalatedwith komatiitic and basaltic lavas near Mashhad and Fariman.


3. Darrehanjir peridotites contain low Cr# spinel, similar to that inMORB-type peridotites. These mantle rocks contain clinopyroxeneswith elevated Al2O3, Na2O and TiO2 contents, suggesting that theseare residual after low degrees of partial melting.

4. Devonian Darrehanjir gabbros and Permian Mashhad sequencesboth have boninitic and calc-alkaline signatures respectively. Latebasaltic dikes crosscutting Darrehanjir Devonian gabbros showcalc-alkaline affinities. Ultramafic (komatiitic) and mafic pillowedlavas from the Permian Mashhad and Fariman ophiolites are deplet-ed in Nb whereas massive lava flows are OIB-like.

5. Our geochemical data further indicate Devonian subduction-relatedmagmatism fromadepletedmantle influenced by subduction inputs.

6. In situ zircon Hf as well as whole rock Sr–Nd–Pb isotopes also indi-cate that gabbroic and plagiogranitic rocks formed from melts ofdepleted mantle that was either affected by subducted sedimentsor was contaminated by continental crust.

7. The Devonian rocks have SSZ characteristics and may reflect earlypulses of subduction within Paleo-Tethys near the Eurasia margin,whereas Permian basalts and komatiites may reflect the role of amantle plume.

8. Our newdating results and compilation of the Ar–Ar and stratigraph-ic ages from literature suggest that Paleo-Tethys was opened at leastfor ~200 Ma as shown by pulses of oceanic magmatism in Devonianand Permian time.

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.gr.2014.06.009.

Acknowledgments

This research was supported by the “Strategic Priority Research Pro-gram (B)” of the Chinese Academy of Sciences (Grant no.XDB03010800) to XHL and the State Key Laboratory of LithosphericEvolution, IGG-CAS to HSM. We are very grateful to A. Zanchi and Y.Eyuboglu for their constructive reviews of the manuscript. We thankDr. Inna Safonova (associated editor) for her helpful comments whichenhanced the scientific value of this paper. This is a contribution toIGCP#592 project “continental construction in Central Asia”. We wishalso to acknowledge Y.X. Xiang and Q.L. Li for their assistance duringgeochemical analyses and SIMS dating.

References

Aharipour, R., Moussavi, M.R., Mosaddegh, H., Mistiaen, B., 2010. Facies features andpaleoenvironmental reconstruction of the Early to Middle Devonian syn-riftvolcano-sedimentary succession (Padeha Formation) in the Eastern-Alborz Moun-tains, NE Iran. Facies 56, 279–294.

Alabaster, T.,Pearce, J.A.,Malpas, J., 1982. The volcanic stratigraphy and petrogenesis of theOman ophiolite. Contributions to Mineralogy and Petrology 81, 168–183.

Alavi, M., 1991. Sedimentary and structural characteristics of the Paleo-Tethys remnantsin northeastern Iran. Geological Society of America Bulletin 103, 983–992.

Angiolini, L.,Gaetani, M.,Muttoni, G., Stephenson, M.H., Zanchi, A., 2007. Tethyan oceaniccurrents and climate gradients 300 m.y. ago. Geology 35, 1071–1074.

Anonymous, 1972. Penrose field conference on ophiolites. Geotimes 17 (12), 22–24.Arculus, R.J., 2003. Use and abuse of the term calcalkaline and calcalkalic. Journal of

Petrology 44, 929–935.Arndt, N.T.,Ginibre, C.,Chauvel, C.,Albarede, F.,Cheadle, M.,Herzberg, C.,Jenner, G.,Lahaye,

Y., 1998. Were komatiites wet? Geology 26, 739–742.Bagheri, S., Stampfli, G.M., 2008. The Anarak, Jandaq and Posht-e-Badam metamorphic

complexes in central Iran: new geological data, relationships and tectonic implications.Tectonophysics 451, 123–155.

Boulin, J., 1980. Introduction a la geologie des Monts de Turkman, en Afghanistan:l'importance des evenements hercyniens et cimmeriens. Revue de GeologieDynamique et de Geographie Physique, Paris 3, 187–199.

Boulin, J., 1988. Hercynian and Eocimmerian events in Afghanistan and adjoining regions.Tectonophysics 148, 253–278.

Buchs, D.M.,Bagheri, S.,Martin, L.,Hermann, J.,Arculus, R., 2013. Paleozoic to Triassic oceanopening and closure preserved in Central Iran: constraints from the geochemistry ofmeta-igneous rocks of the Anarak area. Lithos 172–173, 267–287.

Cavosie, A.J., Kita, N.T., Valley, J.W., 2009. Mantle oxygen-isotope ratio recorded inmagmatic zircon from the Mid-Atlantic Ridge. American Mineralogist 9, 926–934.

Coleman, R.G., 1977. Ophiolites—Ancient Oceanic Lithosphere? Minerals and Rocks, 12.Springer-Verlag (229 pp.).

Dai, J.G.,Wang, C.S.,Hebert, R.,Santosh, M.,Li, Y.L.,Xu, J.Y., 2011. Petrology and geochem-istry of peridotites in the Zhongba ophiolite, Yarlung Zangbo Suture Zone: implica-tions for the Early Cretaceous intra-oceanic subduction zone within the Neo-Tethys.Chemical Geology 288, 133–148.

Dick, H.J.B., Bullen, T., 1984. Chromian spinel as a petrogenetic indicator in abyssal andAlpine-type peridotites and spatially associated lavas. Contributions to Mineralogyand Petrology 86, 54–76.

Dilek, Y., 2003. Ophiolite concept and its evolution. In: Dilek, Y., Newcomb, S. (Eds.),Ophiolite Concept and the Evolution of Geological Thought. Geological Society ofAmerica Special Paper, 373, pp. 1–16.

Domeier, M., Torsvik, T.H., 2014. Plate tectonics in Late Paleozoic. Geoscience Frontiers1–48.

Eftekharnezhad, J., Behroozi, A., 1991. Geodynamic significance of recent discoveries ofophiolites and Late Paleozoic rocks in NE Iran (including Kopet Dagh). Abhandlungender Geologischen Bundesanstalt 38, 89–100.

Faure, G.,Mensing, T., 2004. Isotopes: Principles and Applications. John Wiley & Sons Inc.Fitton, J.G., Saunders, A.D., Norry, M.J., Hardarson, B.S., Taylor, R.N., 1997. Thermal and

chemical structure of the Iceland plume. Earth and Planetary Science Letters 153,197–208.

Gamkrelidze, I.P., Shengelia, D.M., Shvelidze, Iu.U.,Vashakidze, G.T., 1999. The new dataabout geological structure of the Lokhi crystalline massif and Gorastskalimetaophiolites. Proceedings of Geological Institute of Academy of Sciences Georgia,New Series 114, 82–108.

Garzanti, E.,Gaetani, M., 2002. Unroofing history of late Paleozoic magmatic arcs withinthe “Turan plate” (Tuarkyr, Turkmenistan). Sedimentary Geology 151, 67–87.

Ghazi, M.,Hassanipak, A.A.,Tucker, P.J.,Mobasher, K., 2001. Geochemistry and 40Ar–39Arages of theMashhadOphiolite, NE Iran. Eos, Transactions of theAmericanGeophysicalUnion 82 (47) (Fall Meet.).

Godard, M.,Dautria, J.M., Perrin, M., 2003. Geochemical variability of the Oman ophiolitelavas: relationship with spatial distribution and paleomagnetic directions. Geochem-istry, Geophysics, Geosystems 4 (G), 8609. http://dx.doi.org/10.1029/2002GC000452.

Godard, M., Bosch, D., Einaudi, F., 2006. A MORB source for low-Ti magmatism in theSemail ophiolite. Chemical Geology 234, 58–78.

Grimes, C.B., Ushikubo, T., John, B.E., Valley, J.W., 2011. Uniformly mantle-like δ18O inzircons from oceanic plagiogranites and gabbros. Contributions to Mineralogy andPetrology 161, 13–33.

Grove, T.L.,Parman, S.W., 2004. Thermal evolution of the earth as recorded by komatiites.Earth and Planetary Science Letters 219, 173–187.

Hart, S.R., 1984. A large-scale isotope anomaly in the Southern Hemisphere mantle.Nature 309, 753–757.

Hauff, F.,Hoernle, K.,Schmidt, A., 2003. Sr–Nd–Pb composition of Mesozoic Pacific oceaniccrust (Site 1149 and 801, ODP Leg 185): implications for alteration of ocean crust andthe input into the Izu–Bonin–Mariana subduction system. Geochemistry, Geophysics,Geosystems 4. http://dx.doi.org/10.1029/2002GC000421.

Hawkins, J.W.,Allan, J.F., 1994. Petrologic Evolution of Lau Basin Sites 834 Through 839. In:Hawkins, J.W., et al. (Eds.), Proceedings of the Ocean Drilling Program, ScientificResults, vol. 135. Ocean Drilling Program, College Station, Texas, pp. 427–470.

He, B., Xu, Y.-G., Huang, X.-L., Luo, Z.-Y., Shi, Y.-R., Yang, Q.-J., Yu, S.-Y., 2007. Age andduration of the Emeishan flood volcanism, SW China: geochemistry and SHRIMPzircon U–Pb dating of silicic ignimbrites, post-volcanic Xuanwei Formation and claytuff at the Chaotian section. Earth and Planetary Science Letters 255, 306–323.

Hout, F.,Hebert, R.,Varfalvy, V.,Beaudoin, G.,Wang, C.S., Liu, Z.F.,Cotten, J.,Dostal, J., 2002.The Beimarang melange (southern Tibet) brings additional constraints in assessingthe origin, metamorphic evolution and obduction processes of the Yarlung Zangboophiolite. Journal of Asian Earth Sciences 21, 307–322.

Jian, P., Liu, D., Kroner, A., Zhang, Q.,Wang, Y., Sun, X., Zhang, W., 2009a. Devonian toPermian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (I): geo-chemistry of ophiolites, arc/back-arc assemblages and within-plate igneous rocks.Lithos 113, 748–766.

Jian, P., Liu, D., Kroner, A., Zhang, Q.,Wang, Y., Sun, X., Zhang, W., 2009b. Devonian toPermian plate tectonic cycle of the Paleo-Tethys Orogen in southwest China (II): in-sights from zircon ages of ophiolites, arc/back-arc assemblages and within-plateigneous rocks and generation of the Emeishan CFB province. Lithos 113, 767–784.

Jiang, Y.H.,Liao, S.Y.,Yang, W.Z.,Shen, W.Z., 2008. An island arc origin of plagiogranites atOytag, western Kunlun orogen, northwest China: SHRIMP zircon U-Pb chronology, el-emental and Sr-Nd-Hf isotopic geochemistry and Paleozoic tectonic implications.Lithos 106, 323–335.

Johnson, K.T.M., Dick, H.J.B., 1992. Open system melting and temporal and spatialvariation of peridotite and basalt at theAtlantic II fracture zone. Journal of GeophysicalResearch 97, 9219–9241.

Johnson, M.C.,Plank, T., 1999. Dehydration and melting experiments constrain the fate ofsubducted sediments. Geochemistry, Geophysics, Geosystems 1. http://dx.doi.org/10.1029/1999GC000014.

Johnson, K.T.M.,Dick, H.J.B.,Shimizu, N., 1990. Melting in the oceanic upper mantle: an ionmicroprobe study of diopsides in abyssal peridotites. Journal of Geophysical Research95, 2661–2678.

Kamenetsky, V.S.,Crawford, A.J.,Meffre, S., 2001. Factors controlling chemistry of magmat-ic spinel: an empirical study of associated olivine, Cr-spinel and melt inclusions fromprimitive rocks. Journal of Petrology 42, 655–671.

Karimpour, M.H., Stern, C.R., Farmer, G.L., 2010. Zircon U-Pb geochronology, Sr-Ndisotope analyses, and petrogenetic study of the Dehnow diorite and Kuhsangigranodiorite (Paleo-Tethys), NE Iran. Journal of Asian Earth Sciences 37,384–393.

Karimpour,M.H.,Stern, C.R.,Farmer, G.L., 2011. Zircon U–Pb geochronology, Sr–Nd isotopeanalyses, and petrogenetic study of the Dehnow diorite and Kuhsangi granodiorite(Paleo-Tethys), NE Iran. Journal of Asian Earth Sciences 37, 384–393.



http://refhub.elsevier.com/S1342-937X(14)00221-4/rf0010



























































http://dx.doi.org/10.1029/2002GC000452











http://dx.doi.org/10.1029/2002GC000421


























http://dx.doi.org/10.1029/1999GC000014

http://dx.doi.org/10.1029/1999GC000014















Kozur, H., Mostler, H., 1991. Beitrage zur Erforschung der Mesozoichen Radiolarien.Geologische und Paläontologische Mitteilungen Innsbruck 1, 1–208.

Kusky, T.,Windley, B., Safonova, I.,Wakita, K.,Wakabayashi, J., Polat, A., Santosh, M., 2013.Recognition of Ocean Plate Stratigraphy in accretionary orogens through Earthhistory: a record of 3.8 billion years of sea floor spreading, subduction, and accretion.Gondwana Research 24, 501–547.

Leake, B.E., et al., 1997. Nomenclature of amphiboles: report of the Subcommittee onamphiboles of the International Mineralogical Association Commission on NewMinerals and Mineral Names. Mineralogical Magazine 61, 295–321.

LeBas, M.J., 2000. IUGS reclassification of the high-Mg and picritic volcanic rocks. Journalof Petrology 41, 1467–1470.

Li, X.H., Faure, M., Lin, W.,Manatschal, G., 2013. New isotopic constraints on age andmagma genesis of an embryonic oceanic crust: the Chenaillet Ophiolite in theWestern Alps. Lithos 160–161, 283–291.

Li, C.,Xiao, W.,Han, C., Zhou, K., Zhang, J., Zhang, Z., 2014. Late Devonian–Early Permianaccretionary orogenesis along the North Tianshan in the southern Central AsianOrogenic Belt. International Geology Review 68. http://dx.doi.org/10.1080/00206814.2014.9132.

Liu, X., Xu, J., Castillo, P.R., Xia, W., Shi, Y., Fenga, Z., Guo, L., 2013. The Dupal isotopicanomaly in the southern Paleo-Asian Ocean: Nd–Pb isotope evidence from ophiolitesin Northwest China. Lithos 189, 185–200.

Majidi, B., 1981. The ultrabasic lava flows of Mashhad, North East Iran. Geological Maga-zine 118, 49–58.

Maruyama, S.,Kawai, T.,Windley, B.F., 2010. Ocean plate stratigraphy and its imbricationin an accretionary orogen: the Mona complex, Anglesey–Lleyn, Wales, UK. GeologicalSociety, London, Special Publications 338, 55–75.

McCulloch,M.T.,Gregory, R.T.,Wasserburg, G.T.,Taylor, H.P., 1981. Sm–Nd, Rb–Sr, and 18O/16Oisotopic systematics in an oceanic crustal section: evidence from the Samail ophiolite.Journal of Geophysical Research 86, 2721–2735.

Meng, F., Cui, M.,Wu, X., Ren, Y., 2013. Heishan mafic–ultramafic rocks in the Qimantagarea of Eastern Kunlun, NW China: remnants of an early Paleozoic incipient islandarc. Gondwana Research 23, 825–836.

Menzies, M.A., Long, A., Ingram, G., Tatnell, M., Janecky, D., 1993. MORB peridotite–seawater interaction: experimental constraints on the behavior of trace elements, 87Sr/86Sr and 143Nd/144Nd ratios. In: Prichard, H.M., Alabaster, T., Harris, N.B.W., Neary,C.R. (Eds.), Magmatic Processes and Plate Tectonics. Geological Society Special Publi-cation London, 76, pp. 309–322.

Metcalfe, I., 2006. Paleozoic and Mesozoic tectonic evolution and palaeogeography of EastAsian crustal fragments: The Korean Peninsula in context. Gondwana Research 9,24–46.

Mirnejad, H.,Lalonde, A.E.,Obeid, M.,Hassanzadeh, J., 2013. Geochemistry and petrogene-sis of Mashhad granitoids: An insight into the geodynamic history of the Paleo-Tethysin northeast of Iran. Lithos 170, 105–116.

Mirsakhanov, M.W. (Ed.), 1989. Geologic map of Turkmenistan, scale 1:500000.Turkmengeologyia Ashkabad (in Russian).

Miyashiro, A., 1974. Volcanic rock series in island arcs and active continental margins.American Journal of Science 274, 321–355.

Moani, S.,Valley, J.W., 2001. Oxygen isotope ratios of zircon: magma genesis of low δ18Ogranites from the British Tertiary Igneous Province, western Scotland. Earth andPlanetary Science Letters 184, 377–392.

Muttoni, G.,Gaetani, M.,Kent, D.V.,Sciunnach, D.,Angiolini, L.,Berra, F.,Garzanti, E.,Mattei,M., Zanchi, A., 2009. Opening of the Neotethys Ocean and the Pangea B to Pangea Atransformation during the Permian. GeoArabia 14, 17–48.

Nicolas, A., 1989. Structure of Ophiolites and Dynamics of Oceanic Lithosphere. KluwerAcademic Publications (367 pp.).

Omrani, H., Moazzen, M., Oberhansli, R., Tsujimori, T., Bousouet, R., Moayyed, M.,2013. Metamorphic history of glaucophane–paragonite–zoisite eclogites fromthe Shanderman area, northern Iran. Journal of Metamorphic Geology 31,91–812.

Pearce, J.A., 2008. Geochemical fingerprinting of oceanic basalts with applications toophiolite classification and the search for Archean oceanic crust. Lithos 100, 14–48.

Pearce, J.A., Peate, D.W., 1995. Tectonic implications of the composition of volcanic arcmagmas. Annual Review of Earth and Planetary Sciences 23, 251–285.

Plank, T.,Langmuir, C.H., 1998. The chemical composition of subducting sediment and itsconsequences for the crust and mantle. Chemical Geology 145, 325–394.

Plank, T.,Kelley, K.A.,Murray, R.W., Stern, L.Q., 2007. Chemical composition of sedimentssubducting at the Izu–Bonin trench. Geochemistry, Geophysics, Geosystems 8.http://dx.doi.org/10.1029/2006GC001444.

Rao, R., Rai, H., 2007. Permian komatiites and associated basalts from the marine sedi-ments of Chhongtash Formation, southeast Karakoram, Ladakh, India. Mineralogyand Petrology 91, 171–189.

Reagan, M.K., Ishizuka, O., Stern, R.J., Kelley, K.A.,Ohara, Y., Blichert-Toft, J., Bloomer, S.H.,Cash, J., Fryer, P., Hanan, B.B., Hickey-Vargas, R., Ishii, T., Kimura, J.I., Peater, D.W.,Rowe, M.C.,Woods, M., 2010. Fore-arc basalts and subduction initiation in the Izu–Bonin–Mariana system. Geochemistry, Geophysics, Geosystems 11. http://dx.doi.org/10.1029/2009GC002871.

Reichow, M.K.,Pringle, M.S.,Al'Mukhamedov, A.I.,Allen, M.B.,Andreichev, V.L.,Buslov, M.M.,Davies, C.E., Fedoseev, G.S., Fitton, J.G., Inger, S., Medvedev, A.Y., Mitchell,C., Puchkov, V.N., Safonova, I.Y., Scott, R.A., Saunders, A.D., 2009. The timing andextent of the eruption of the Siberian Traps large igneous province: implicationsfor the end-Permian environmental crisis. Earth and Planetary Science Letters277, 9–20.

Robert, A.M.M.,Letouzey, J.,Kavoosi, M.A.,Sherkati, S.,Muller, C.,Verges, J.,Aghababaei, A.,2014. Structural evolution of the Kopeh Dagh fold-and-thrust belt (NE Iran) andinteractions with the south Caspian Sea Basin and Au Darya Basin. Marine and Petro-leum Geology 57, 68–87.

Rolland, Y.,Sosson, M.,Adamia, Sh.,Sadradze, N., 2011. Prolonged Variscan to Alpine his-tory of an active Eurasian margin (Georgia, Armenia) revealed by 40Ar/39Ar dating.Gondwana Research 20, 798–815.

Ross, K.,Elthon, D., 1993. Cumulates from strongly depletedmid-ocean basalt. Nature 365,826–829.

Ruttner, A.W., 1993. Southern borderland of Triassic Laurasia in northeast Iran.Geologische Rundschau 82, 110–120.

Safonova, I.,Maruyama, S., 2014. Asia: a frontier of a future supercontinent Amasia.International Geology Review. http://dx.doi.org/10.1080/00206814.2014.915586.

Safonova, I.Y.,Santosh, M., 2014. Accretionary complexes in the Asia-Pacific region: Trac-ing archives of ocean plate stratigraphy and tracking mantle plumes. Gondwana Re-search 25, 126–158.

Safonova, I., Seltmann, R.,Kröner, A.,Gladkochub, D., Schulmann, K.,Xiao, W.,Komiya, T.,Sun, M., 2011. A new concept of continental construction in the Central Asian Oro-genic Belt (compared to actualistic examples from the Western Pacific). Episodes34, 186–194.

Schwab, M., Ratschbacher, L., Siebel, W.,McWilliams, M.,Minaev, V., Lukov, V., Chen, F.,Stanek, K.,Nelon, B., Frisch, W.,Wooden, J.L., 2004. Assembly of the Pamirs: age andorigin of magmatic belts from the southern Tien Shan to the southern Pamirs andtheir relation to Tibet. Tectonics 23. http://dx.doi.org/10.1029/2003TC001583.

Sengor, A.M.C.,Natalin, B.A., 1996. Paleotectonics of Asia: fragments of a synthesis. In: Yin,A., Harrison, T.M. (Eds.), The Tectonic Evolution of Asia. Cambridge University Press,pp. 486–640.

Sengor, A.M.C.,Altiner, D.,Cin, A.,Ustaomer, T.,Hsu, K.J., 1988. Origin and assembly of theTethyside orogenic collage at the expense of Gondwana Land. Geological Society ofLondon, Special Publication 37.

Shafaii Moghadam, H.,Stern, R.J., 2011. Geodynamic evolution of upper Cretaceous Zagrosophiolites: formation of oceanic lithosphere above a nascent subduction zone.Geological Magazine 148, 762–801.

Shafaii Moghadam, H.,Zaki Khedr,M.,Arai, S.,Stern, R.J.,Ghorbani, G.,Tamura, A.,Ottley, C.J.,2015. Arc-related harzburgite–dunite–chromitite complexes in the mantle section ofthe Sabzevar ophiolite, Iran: a model for formation of podiform chromitites.Gondwana Research 25, 575–593.

Shafaii Moghadam, H.,Stern, R.J., 2014. Ophiolites of Iran: Keys to understanding the tec-tonic evolution of SW Asia: (I) Paleozoic ophiolites. Journal of Asian Earth Sciences91, 19–38.

Sheikholeslami, M.R.,Kouhpeyma, M., 2012. Structural analysis and tectonic evolution ofthe eastern Binalud Mountains, NE Iran. Journal of Geodynamics 61, 23–46.

Shellnutt, J.G., Bhat, G.M., Wang, K.-W., Brookfield, M.E., Jahn, B.-N., Dostal, J., 2014.Petrogenesis of the flood basalts from the Early Permian Panjal Traps, Kashmir,India: geochemical evidence for shallow melting of the mantle. Lithos. http://dx.doi.org/10.1016/j.lithos.2014.01.008.

Shervais, J.W., 1982. Ti–V plots and the petrogenesis of modern ophiolitic lavas. Earth andPlanetary Science Letters 59, 101–118.

Shi, R.,Griffin, W.L.,O'Reilly, S.Y.,Huang, Q.,Zhang, X., Liu, D.,Zhi, X.,Xia, Q.,Ding, L., 2012.Melt/mantle mixing produces podiform chromite deposits in ophiolites: implicationsof Re–Os systematics in the Dongqiao Neo-tethyan ophiolite, northern Tibet.Gondwana Research 21, 194–206.

Snow, J.E., Dick, H.J.B., 1995. Pervasive magnesium loss by marine weathering ofperidotite. Geochimica et Cosmochimica Acta 59, 4219–4235.

Sobolev, A.V.,Shimizu, N., 1993. Ultra-depleted primary melt included in an olivine fromthe Mid-Atlantic Ridge. Nature 363, 151–154.

Stakes, D.S.,Franklin, J.M., 1994. Petrology of Igneous Rocks at Middle Valley, Juan de FucaRidge. In: Mottl, M.J., Davis, E.E., Fisher, A.T., et al. (Eds.), Proceedings of the OceanDrilling Program, Scientific Results, 139. College Station, Texas, pp. 79–102.

Stampfli, G.M., 1978. Etude Geologique generale de l'Elbourz oriental au sud de Gonbad-e-Qabus (Iran, NE)(PhD Thesis) Universite de Geneve (329 pp.).

Stampfli, G.M.,Borel, G.D., 2002. A plate tectonic model for the Paleozoic and Mesozoicconstrained by dynamic plate boundaries and restored synthetic oceanic isochrons.Earth and Planetary Science Letters 196, 17–33.

Stampfli, G.M., Marcoux, J., Baud, A., 1991. Tethyan margins in space and time.Palaeogeography, Palaeoclimatology, Palaeoecology 87, 373–409.

Stracke, A., Bizimis, M., Salters, V.J.M., 2003. Recycling oceanic crust: quantitativeconstraints. Geochemistry, Geophysics, Geosystems 4, 8003.

Su, B.Q.,Qin, K.Z., Sakyi, P.A., Li, X.-H., Yang, Y.H., Sun, H., Tang, D.M., Liu, P.P.,Xiao, Q.-H.,Malaviarachchi, S.P.K., 2011. U–Pb ages and Hf–O isotopes of zircons from Late Paleo-zoic mafic–ultramafic units in the southern Central Asian Orogenic Belt: tectonic im-plications and evidence for an Early-Permian mantle plume. Gondwana Research 20,516–531.

Sun, S.S.,McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes. In: Saunders, A.D., Norry, M.J.(Eds.), Magmatism in Ocean Basins. Geological Society Special Publication, London,pp. 313–345.

Thirlwall, M.F.,Smith, T.E.,Graham, A.M.,Theodorou, N.,Hollings, P.,Davidson, J.P.,Arculus,R.J., 1994. High field strength element anomalies in arc lavas: source or process?Journal of Petrology 35, 819–838.

Treloar, P.J.,Mayringer, F.,Finger, F.,Gerdes, A.,Shengalia, D., 2009. New age data from theDzirula Massif, Georgia: implications for Variscan evolution of the Caucasus. 2ndInternational Symposium on the Geology of the Black Sea Region, Abstract book,pp. 204–205.

Ustaomer, T., Robertson, A.H.F., 1993. A late Palaeozoic–early Mesozoic marginal basinalong the active southern continental margin of Eurasia: evidence from the CentralPontides (Turkey) and adjacent regions. Geological Journal 28, 219–238.

Valley, J.W., 2003. Oxygen Isotopes in Zircon. In: Hanchar, J.M., Hoskin, P.W.O. (Eds.),Zircon: Reviews in Mineralogy and Geochemistry, 53, pp. 343–385.














http://dx.doi.org/10.1080/00206814.2014.9132

http://dx.doi.org/10.1080/00206814.2014.9132



















































http://dx.doi.org/10.1029/2006GC001444




http://dx.doi.org/10.1029/2009GC002871

















http://dx.doi.org/10.1080/00206814.2014.915586

http://dx.doi.org/10.1080/00206814.2014.915586







http://dx.doi.org/10.1029/2003TC001583


















http://dx.doi.org/10.1016/j.lithos.2014.01.008










































Valley, J.W.,Lackey, J.S.,Cavosie, A.J.,Clechenko, C.C.,Spicuzza, M.J.,Basei, M.A.S.,Bindeman,I.N., Ferreira, V.P., Sial, A.N., King, E.M., Peck, W.H., Sinha, A.K., Wei, C.S., 2005. 4.4 billion years of crustal maturation: oxygen isotope ratios of magmatic zircon.Contributions to Mineralogy and Petrology 150, 561–580.

Van der Laan, S.R.,Arculus, R.J.,Pearce, J.A.,Murton, B.J., 1992. Petrography, Mineral Chem-istry, and Phase Relations of the Basement Boninite Series of Site 786, Izu–BoninForearc. In: Fryer, P., Pearce, J.A., Stokking, L.B., et al. (Eds.), Proceedings of theOcean Drilling Program, Scientific Results, 125. College Station, Texas, pp. 171–201.

Windley, B.F., Alexeiev, D., Xiao, W., Kröner, A., Badarch, G., 2007. Tectonic models foraccretion of the Central Asian Orogenic Belt. Journal of the Geological Society,London 164, 31–47.

Xiao, W.,Windley, B.,Liu, D.Y.,Jian, P.,Liu, C.,Yuan, C.,Sun, M., 2005. Accretionary tectonicsof the Western Kunlun Orogen, China: a Paleozoic–Early Mesozoic, long-lived activecontinental margin with implications for the growth of Southern Eurasia. The Journalof Geology 113 (6), 687–705.

Xiao, W.J.,Li, S.Z.,Santosh, M.,Jahn, B.M., 2012. Orogenic belts in Central Asia: Correlationsand connections. Journal of Asian Earth Sciences 49, 1–6.

Xiao, W.,Windley, B.F., Allen, M.B., Han, C., 2013. Paleozoic multiple accretionary andcollisional tectonics of the Chinese Tianshan orogenic collage. Gondwana Research23 (4), 1316–1341.

Yang, J.,Xu, Z.,Li, Z.,Xu, X., Li, T.,Ren, Y.,Li, H.,Chen, S.,Robinson, T., 2009. Discovery of aneclogite belt in the Lhasa block, Tibet: a new border for Paleo-Tethys? Journal of AsianEarth Sciences 34, 76–89.

Yu, X.,Yang, S.F.,Chen, H.L.,Chen, Z.Q.,Li, Z.L.,Batt, G.E.,Li, Y.Q., 2011. Permian flood basaltsfrom the Tarim Basin, Northwest China: SHRIMP zircon U–Pb dating and geochemicalcharacteristics. Gondwana Research 20, 485–497.

Zakariadze, G.S., Dilek, Y., Adamia, S.A., Adamia, Sh.A., Oberhansli, R.E., Karpenko, S.F.,Bazylev, B.A., Solov'eva, N., 2007. Geochemistry and geochronology of the

Neoproterozoic Pan-African Transcaucasian Massif and implications for island arcevolution of the Late Precambrian Arabian–Nubian Shield. Gondwana Research 11,92–108.

Zanchetta, S.,Zanchi, A.,Villa, I.,Poli, S.,Mottoni, G., 2009. The Shanderman eclogites: a LateCarboniferous high-pressive event in the NW Talesh Mountains (NW Iran). In:Brunet, M.F., Wilmsen, M., Granath, J.W. (Eds.), South Caspian to Central Iran Basins.Geological Society, London, Special Publications, 312, pp. 57–78.

Zanchetta, S., Berra, F., Zanchi, A., Bergomi, M., Caridroit, M.,Nicora, A., Heidarzadeh, G.,2013. The record of the Late Palaeozoic active margin of the Palaeotethys in NEIran: constraints on the Cimmerian orogeny. Gondwana Research 24, 1237–1266.

Zanchi, A.,Zanchetta, S.,Berra, F.,Mattei, M.,Garzanti, E.,Molyneux, S.,Nawab, A.,Sabouri, J.,2009. The Eo-Cimmerian (Late? Triassic) orogeny in north Iran. In: Brunet, M.-F.,Wilmsen, M., Granath, J.W. (Eds.), South Caspian to Central Iran Basins. GeologicalSociety of London Special Publication, 312, pp. 31–55.

Zhai, Q.G., Jahn, B.M.,Wang, J., Su, L.,Mo, X.X.,Wang, K.L., Tang, S.H., Lee, H.Y., 2013. TheCarboniferous ophiolite in the middle of the Qiangtang terrane, Northern Tibet:SHRIMP U–Pb dating, geochemical and Sr–Nd–Hf isotopic characteristics. Lithos168–169, 186–199.

Zhang, Y., Liu, J., Guo, Z., 2010. Permian basaltic rocks in the Tarim basin, NW China:implications for plume–lithosphere interaction. Gondwana Research 18, 596–610.

Zhang, C.L., Yang, D.S.,Wang, H.Y., Takahashi, Y., Ye, H.M., 2011. Neoproterozoic mafic–ultramafic layered intrusion in Quruqtagh of northeastern Tarim Block, NW China:two phases of mafic igneous activity with different mantle sources. GondwanaResearch 19, 177–190.

Zonenshain, L.P.,Kuzmin, M.I.,Natapov, L.M., 1990. Geology of the USSR: a plate tectonicsynthesis. AGU Geodynamic Series 21.



















































Devonian to Permian evolution of the Paleo-Tethys Ocean ...rjstern/pdfs/MoghadamLiGR15.pdf ·...

Documents

Transcript of Devonian to Permian evolution of the Paleo-Tethys Ocean ...rjstern/pdfs/MoghadamLiGR15.pdf ·...