contrasting zircon hf–o isotopes and trace elements...

Lithos 156-159 (2013) 97–111

Contents lists available at SciVerse ScienceDirect

Lithos

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

Contrasting zircon Hf–O isotopes and trace elements between ore-bearing andore-barren adakitic rocks in central-eastern China: Implications for genetic relationto Cu–Au mineralization

Fangyue Wang a,⁎, Sheng-Ao Liu b,⁎, Shuguang Li a,b, Yongsheng He b

a CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, Chinab State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China

⁎ Corresponding authors at: School of Earth and Spaceand Technology of China, Hefei, 230026 Anhui, China. T

E-mail addresses: [email protected] (F. Wang), ls

0024-4937/$ – see front matter © 2012 Elsevier B.V. Allhttp://dx.doi.org/10.1016/j.lithos.2012.10.017

a b s t r a c t
a r t i c l e i n f o
Article history:Received 15 July 2012Accepted 29 October 2012Available online 7 November 2012

Keywords:Zircon Hf–O isotopesCe4+/Ce3+

Oxygen fugacityAdakitePorphyry Cu–Au deposit

The petrogenesis of Early Cretaceous adakitic intrusions in the Lower Yangtze River belt (LYRB), central-easternChina, and their genetic associationwith Cu–Aumineralization have recently been debated. This study presentedintegrated in-situ zircon U–Pb–Hf–O isotopic and trace elemental data for the LYRB adakites, and a comparisonwith ore-barren adakites from the south Tan-Lu fault (STLF) adjacent to the LYRB. Magmatic zircons from thesetwo series of intrusions have U–Pb ages of 145–132 Ma and 136–132 Ma respectively. The STLF zircons haveδ18O ranging from 5.6 to 6.7‰ and εHf(t) from−28.8 to−16.4, plotted within the range of global lower crustalmetabasaltic xenoliths, consistent with low-radiogenic Pb of the host adakitic rocks. In contrast, both Hf and Oisotopic compositions of zircons from the LYRB are greatly variable with heavier δ18O (4.7 to 9.6‰) and higherεHf(t) values (−25.5 to +2.0) compared with the STLF series. The co-variations of Hf–O isotopes in the LYRBseries reflect source heterogeneity as a result of mixing of basaltic oceanic crust with sediments (10–20%), con-sistent with high-radiogenic Pb and enriched Sr–Nd isotopic compositions of the host adakites. The high La, Uand low Ti concentrations in the LYRB zircons also imply a volatile (perhaps, CO3

2−-rich, carbonatite-like) source.Combined with whole-rock geochemical data, the new results further suggest contrasting origins of the LYRBand STLF adakites from subducted oceanic crust and foundering lower continental crust, respectively.The LYRB zircons have much higher ratios of Ce4+/Ce3+ (avg.417) and Eu/Eu* (avg. 0.67) than the STLF zircons(avg. 84 and 0.44). This difference confirms that the ore-bearing adakitic magmas are more oxidized relative tothe ore-barren ones. There is roughly a positive correlation between zircon Ce4+/Ce3+ and δ18O in the LYRB series,probably indicating that the elevated fO2 was related to components enriched in heavy oxygen isotopes. A possiblecandidate is sediments, carried by subducting slabs. The involvement of sediments may significantly promoteoxidation of the resulting adakitic melts, a key factor for generation of Cu–Au mineralization, e.g., in the LYRB.This study also indicates that combined in-situ analysis of zircon REEs and δ18O could be a powerful tool to decipherthe intrinsic links of fO2 with sediment components in subduction zones.

© 2012 Elsevier B.V. All rights reserved.

1. Introduction

Adakite was initially defined by Defant and Drummond (1990) asproducts of partial melting of subducting young and hot oceanic crust(Kay, 1978). In the past decades, numerous studies have shown thatporphyry or hydrothermal-related Cu–Au deposits were commonlyassociated with adakitic rocks (Borisova et al., 2006; Imai, 2002; Linget al., 2009; Liu et al., 2012; Oyarzun et al., 2001; Richards et al., 2012;Sajona and Maury, 1998; Sun et al., 2011, 2012; Tang et al., 2010;Thieblemont et al., 1997; Yang et al., 2011). However, there are alsoadakites that show no correlation with Cu–Au mineralization. It is notclear why some adakites are ore-bearing whereas others are not,

Sciences, University of Scienceel.: +86 551 [email protected] (S.-A. Liu).

rights reserved.

especially for these distributed in the same region and with similar for-mation ages.

Early Cretaceous Cu–Au ore-bearing and ore-barren adakitic intru-sions have been widely recognized in several neighboring regions incentral-eastern China, e.g., the Lower Yangtze River belt (LYRB), thesouth Tan-Lu Fault zone (STLF), and the Dabie mountain (He et al.,2011; Huang et al., 2008; Li et al., 2009a; Liu et al., 2010; Xie et al.,2008a, 2012; Xu et al., 2002). Recently, Wang et al. (2004a,b, 2006,2007b) carried out a series of comparative studies on ore-bearingadakites and ore-barren adakitic rocks from the LYRB and the adjacentDabie mountains. Those authors proposed that high Mg# adakiteswere derived from delaminated lower continental crust (LCC) andthey are favorable for Cu–Au mineralization because they haveinteracted with mantle, while those with low Mg# are directly derivedfrom the thickened LCC and are not related with mineralization. Thisconclusion is recently challenged by Liu et al. (2010), who reported

http://dx.doi.org/10.1016/j.lithos.2012.10.017

mailto:[email protected]

mailto:[email protected]


http://www.sciencedirect.com/science/journal/00244937

98 F. Wang et al. / Lithos 156-159 (2013) 97–111

high Mg# adakites from other belts (e.g., the STLF) but they are notrelated to mineralization, either.

In contrast to the LCC melting model, it has been proposed that theLYRB adakites were derived from partial melting of subducted oceanicslab during a ridge subduction (Ling et al., 2009; Sun et al., 2010),based on the drifting history of the Pacific plate (Sun et al., 2007). Thisis further supported by the characteristic distribution of A-type granites(Li et al., 2012b). Based onwhole rock geochemical differences betweenthe STLF and LYRB adakites, Liu et al. (2010) proposed that the LYRBadakites were generated by partial melting of subducted oceaniccrust, which may be much more favorable source for mineralizationcompared to the delaminated LCC. Therefore, the question is why theLYRB adakites derived from the subducted oceanic slab are associatedwith Cu–Aumineralization compared to the STLF LCC-derived adakites.

One of the key factors for Cu–Au deposits is the oxygen fugacity(fO2). Elevated fO2 could destabilize sulfides, releasing the chalcophileelements (e.g. Cu and Au) to the interacting fluid/melt/supercriticalfluid(s) in themantle wedge. It has long been believed that the conver-gent margin is more oxidizing than intraplate setting (Ballhaus, 1993;Parkinson and Arculus, 1999; Zimmer et al., 2010), due to slab melting(Mungall, 2002) and/or the addition of oxidizing fluids, even decompo-sition of water (Sun et al., 2012). Liu et al. (2010) proposed thatthe “dry” LCC and slab-derived melts/fluids could be very different inthe redox state, but direct evidence for contrasting fO2 between theLCC-derived melts and slab-derived melts is still absent. The major dif-ficulty in studying fO2 of ore-bearing intrusive rocks is the pervasivehydrothermal alteration that has modified their primary textural andchemical characteristics. This has been restricted studying fresh rocks.

Zircon is a common refractory mineral in igneous rocks. The phys-ical and chemical stability of zircon, its tendency to incorporate nu-merous trace and radiogenic elements and extremely low diffusionrates for these elements (Cherniak and Watson, 2003; Scherer et al.,2007; Valley, 2003) make it an ideal mineral to see through the sub-sequent alteration commonly occurred in whole-rocks (Ballard et al.,2002; Liang et al., 2006; Muñoz et al., 2012). It can preserve the intactinformation on magma composition and thus is an excellent tool forgeochronology and geochemical study to trace the magma source(Kemp et al., 2007; Li et al., 2009c) and fO2 (Ballard et al., 2002;Liang et al., 2006; Trail et al., 2011).

In this study, we report an integrated analysis of in-situ U–Pb–Hf–Oisotopes and trace elements [Ti, Th, U, Hf, rare earth elements (REE)] forzircons from the LYRB ore-bearing adakites and the STLF ore-barrenhigh Mg# adakitic rocks. Some of these samples were previously stud-ied for whole-rock geochemistry (Liu et al., 2010). Because the ore-bearing and ore-barren high Mg# adakites were both intruded in theYangtze block, a comprehensive comparison can elucidate the differ-ences of the magmatic processes. The primary purpose of this study isto compare the redox state of these two suites of magmas as a factorcontrolling their genetic links to Cu–Au mineralization.

2. Geological background and sample descriptions

The central-eastern China consists of the North China Craton to thenorth and the South China Block to the south, separated by theQinling-Dabie orogenic belts (inset of Fig. 1). The South China Block issubdivided into the Yangtze Block to the north and the CathaysiaBlock to the south by the Jiangshan-Shaoxing Fault (JSF) (Chen andJahn, 1998; Li and McCulloch, 1996; Li et al., 2005, 2009b; Zhao andCawood, 1999). The Dabie-Sulu orogenic belt is the largest knownultrahigh pressure metamorphic zone on the Earth, formed by north-ward subduction of the Yangtze Block beneath the North China Cratonin the Triassic (Cong and Wang, 1999; Li et al., 1993, 2000; Zhenget al., 2003). Due to a sinistral strike-slip movement of the Tan-LuFault (TLF) during the period of Late Mesozoic, the Sulu orogeny wasdisplaced ~500 km to the north of the Qinling-Dabie section (Zhu

et al., 2001). Thus, the TLF constitutes a tectonic suture between theYangtze Block and the North China Block.

The LYRB is situated along the Yangtze River valley located in thenortheast portion of the Yangtze Block (Fig. 1). The outcropping rocksin the LYRB consist of a Palaeozoic basement and a sequence ofMesozoicsedimentary rocks (Chang et al., 1991; Gao et al., 1999; Zhang et al.,2006a). The stratigraphic sequences exposed range from Silurian toTriassicwith thickness up to 3000m. The sequence includes Silurian shal-low marine sandstones interbedded with shales, Devonian continentalquasi-molasse formation and lacustrine sediments, Carboniferousshallow marine carbonates, Permian marine facies alternating with amarine-continental ones, Early to Middle Triassic shallow marine car-bonates. Overlying these sediments is Jurassic and Cretaceous volcanicrocks, which are mainly ignimbrite, tuff, andesite, rhyolite, trachyte andbasalt in several volcanic basins (Xie et al., 2011b; Zhou et al., 2008).Upper Cretaceous to Tertiary rocks are characterized by red-bed clasticsediments intercalated with minor Paleogene basalt (Xie et al., 2011b).

The LYRB belt makes up one of themost important metallogenic beltsin China and comprises seven major deposit districts from southwest tonortheast along the Yangtze River (Fig. 1). The ore deposits throughoutthe LYRB are clustered into seven districts from west to east: (1) Edong(mainly Fe skarn and Cu porphyry deposit); (2) Jiurui (Cu–Au–Moskarn, porphyry and strata-bound deposits); (3) Anqing-Guichi (Cu–Moskarn and strata-bound deposits); (4) Luzong (Fe intrusion-hosted andCu porphyry deposits); (5) Tongling (Cu–Au–Fe–S skarn and strata-bound deposits); (6) Ningwu Fe intrusion-hosted deposits) and(7) Ningzhen (Fe–Cu–Mo) skarn and porphyry deposits (Chang et al.,1991; Ling et al., 2009; Pan and Dong, 1999) (Fig. 1). Dating of theore-forming minerals indicates that they were mainly formed in theearly Cretaceous (143–134 Ma) and the skarn, porphyry and strata-bound mineralization were generally contemporaneous (Mao et al.,2006; Sun et al., 2003; Xie et al., 2008a). The host intrusions aremainly di-oritic to granitic porphyry rocks with emplacement ages identical to theformation ages of associated deposits (~143–134 Ma; Li et al., 2009a,2010b; Wang et al., 2004a, 2006; Xie et al., 2008b), indicating that thehost intrusions and the ore deposits are both spatially and temporallyassociated. These ore-bearing rocks are I-type (Chang et al., 1991; Xing,1999) and previousworkers have argued that they are highMg# adakiticrockswith high Sr/Y and low Yb contents (Li et al., 2009a; Liu et al., 2010;Wang et al., 2004a,b; Xie et al., 2008a, 2012; Xu et al., 2002). Inthis study, five samples from four representative ore-bearing adakiticintrusions, Tonglushan (30°05′23.1″N, 114°56′11.0″E), Fengshandong(29°49′13.5″N, 115°29′4.7″E), Wushan (29°44′48.4″N, 115°38′40.1″E)and Tongguanshan (30°54′47.9″N, 117°49′5.5″E) (Fig. 1) in theLYRB, were selected for zircon geochemical studies. Sample fromTonglushan (TLS01) is a fresh granodiorite, which is composed of plagio-clase (50–55%), amphibole (30–35%), quartz (10–15%), biotite (5–10%)with minor magnetite, zircon and titanite. Samples from Fengshandong(FS07) and Wushan (WS02) are fresh granodiorite porphyry, composedby phenocrysts (plagioclase (2–10 mm), amphibole (1–5 mm) and bio-tite (2–3 mm)) and plagioclase-rich matrix. Whole rocks geochemistrystudy have been carried out by Jiang et al. (2008) and Xie et al. (2008a),respectively. The studied Tongguanshan quartz diorite sample (TGS-7)is the same as studied in Liu et al. (2010) and the detailed sample petrol-ogy and geochemistry can be found there.

The STLF refers here to regions adjacent to the southpart of the Tan-Lufault zone, including regions from both the eastern Yangtze Block andthe eastern margin of the Dabie orogen. This belt is adjacent to theLYRB on the north (Fig. 1). Previous studies have identified several EarlyCretaceous dioritic to granodioritic intrusions (identified as high-Mgadakitic rocks) along the STLF, including plutons from Chituling,Guanghui, Meichuan, Guandian, Wawuliu, Wawuxue, Fangjiangzhuang,Damaocun, Xiaolizhuang and Qiaotouji intrusions (Fig. 1) (Huanget al., 2008; Liu et al., 2010; Niu et al., 2002; Zi et al., 2008). In thisstudy, zircons from three intrusions in the STLF in the eastern YangtzeBlock, i.e., Fangjiangzhuang (N32°38′53.9″, E118°02′45.0″), Damaocun

North China Block

North China Block

Tan-

Lu fa

ult z

one

Sulu belt

Pa

cific pla

teLYRBJSF

Cathysia Block

Dabie UHP belt

Wuhan

0 100km

Bengbu

Hefei

Ore-bearing high-Mg adakites

Mineralized district

Ore-barren high-Mg adakites

Ore-barren low-Mg adakites

Cu-Au/Fe deposits

No

N3

2o

N3

0

oE115 oE117 oE119

Nanjing

Ningzhen

Ningwu

Tongling

Luzong

Anqing-Guichi

Jiurui

Edong1

2

4

5

6

7

STL

F

Dabie

Guanghui

Chituling

Meichuang

Qiaotouji

Wawuxue

Wawuliu

Guandian

Fangjiangzhuang

Damaocun

Xiaolizhuang

Sample locations

Yangtze Block

Yangtze Block

LYRB

Tonglushan

Fengshandong

Wushan

3

Tongguanshan

Fig. 1. Geologic map of central-eastern China, showing the distributions of Mesozoic adakitic rocks associated with Cu–Au–Fe deposits from the Lower Yangtze River belt (LYRB)and the South Tan-Lu fault (STLF) (modified after Liu et al., 2010; Mao et al., 2006). JSF in the inset denotes the Jiangshan-Shaoxing fault which represents the geological boundarybetween the Yangtze and Cathaysia Blocks.

99F. Wang et al. / Lithos 156-159 (2013) 97–111

(N32°36′08″, E118°21′45″) and Qiaotouji (N31°39′39.2″, E117°32′59.8″)were studied. These rocks intrude into Mesoproterozoic metamorphicbasement (Zhangbaling group) (Lin et al., 2005).The samples analyzedhere are the same as studied by Liu et al. (2010).

3. Analytical methods

Zircon grains were separated usingmagnetic and heavy liquid sepa-ration methods and finally by hand-picking under a binocular micro-scope. About 100–200 grains for each sample were mounted in epoxytogether with the zircon standard TEMORA (Black et al., 2004). Priorto U–Th–Pb–O–Hf isotope analysis, all grains were documented withtransmitted and reflected-light as well as cathodoluminescence (CL)image to reveal their internal structures. Tiny melt/fluid/apatite inclu-sions commonly captured in zircons were avoided during in-situ analy-ses. Zircons of the three plutons in the STLF were previously dated byLiu et al. (2010) using Cameca-IMS 1280 in the secondary ion massspectrometry (SIMS) center of the Institute of Geology and Geophysics,Chinese Academy of Science (IGGCAS). Zircon oxygen isotopes wereanalyzed in this study using a Cameca-IMS 1280 in the SIMS center ofIGGCAS following the procedure outlined in Li et al. (2009c, 2010a).The instrumental mass fractionation factor (IMF) was corrected usingTEMORA zircon standard with a δ18O value of 8.2‰ (Black et al.,2004). The internal accuracy achieved based on a set of analysesof matrix-matched reference material was commonly better than±0.5‰ (2SD). Measured values of δ18O are reported in the standarddelta notation (per mil, ‰) relative to VSMOW. Repeated analyzes ofan in-house standard (Qinghu zircon) during the course of sampleanalysis yielded mean δ18O value of 5.35±0.10‰ (2σ; n=24), whichis in good agreement with previously reported value (5.4±0.3‰) ofQinghu zircon (Li et al., 2009c).

In-situ measurement of U–Pb–Hf isotopes and trace elements in thezircon grains of DMC-1, FJZ-1, QTJ-2 and TGS-7were simultaneously car-ried out using a Varian 820-MS quadrupole and aNu PlasmaHRmultiplecollector-inductively coupled plasma-mass spectrometer (Q-ICPMS andMC-ICPMS, respectively), connected to a GeoLas2005 193-nm singleexcimer ArF laser-ablation system at the State Key Laboratory of

Continental Dynamics, Northwest University, China. In-situ measure-ment of zircon grains from sample TLS01, FS07 and WS02 were carriedout using LA-MC-ICPMS for Hf isotopes in Northwest University andLA-ICPMS for U–Pb isotopes and trace elements in Chinese Academy ofScience Key Laboratory of Crust–Mantle Materials and Environments,University of Science and Technology of China (USTC) in the same spot.Standards 91500, Mon-1, GJ-1 and NIST610 were analyzed during theanalyses. All analyses were carried out with a beam diameter of 44 μm,a repetition rate of 8 Hz, and energy of 2.4J/cm2. The analytical proce-dures for zircon U–Pb–Hf isotopes were similar to those described byYuan et al. (2008). Zircon U–Pb isotopes and trace elements analyticalprocedures in the USTC were similar to those described by Wang et al.(2012).The analyses were carried out with pulse rate of 10Hz andbeam energy of 10 J/cm2 with spot diameter of 44 μm. 29Si was usedas internal standards for zircon. Certified glass reference material NISTSRM 610 was used as an external standard, which was analyzed twicefor every 4 analyses.

Off-line selection, integration of background and analytical signals,time-drift corrections, quantitative calibrations for trace element analy-ses and U–Pb dating, were performed using the software ICPMSDataCal7.1 (Liu et al., 2008), LaTEcalc and LaDating (HouZhenhui, personalcommunication). During the time-resolved analysis of zircons, contam-ination resulting from inclusions, fractures, and zones of different com-position was monitored by several elements (e.g., P and La) and onlythe relevant part of the signal was integrated. Concordia diagramsand weighted mean calculations were made using Isoplot/Ex_ver3(Ludwig, 2003). Analyses of rock standards (91500, and NIST 610)indicate that the precision (RSD%) is better than 10% for these elements,e.g., Sm concentration in 91500 (0.33±0.05ppm; 2σ, n=15), is close tothe secondary ionization mass spectrometry (SIMS) working value(0.38 ppm) (Wiedenbeck et al., 2004). Zircon standards GJ-1 were ana-lyzed as unknown. The obtained mean 206Pb/238U age for GJ-1 is606.7±2.6Ma (2σ, n=48) consistent with the recommended values(GJ-1: 599.8±1.7 Ma; 2σ) (Jackson et al., 2004).

The corrections to raw Lu–Hf isotope data followed the protocols ofYuan et al. (2008). Measurement of reference standards zircons 91500,Monastery, and GJ-1 during our routine analyses, yielded 176Hf/177Hf


ratios of 0.282340±0.000014 (2σ, n=52), 0.282750±0.000012 (2σ,n=26) and 0.281990±0.000022 (2σ, n=10), respectively, whichare well consistent with the recommended 176Hf/177Hf ratios of0.282306±0.000010 for 91500 (Woodhead et al., 2004), 0.282738±0.000004 for Monastery (Woodhead and Hergt, 2005), and0.282015±0.000019 for GJ-1 (Elhlou et al., 2006).

The measured 176Lu/177Hf ratios and the 176Lu decay constant of1.865×10−11 year−1 reported by Scherer et al. (2001)were used to cal-culate initial 176Lu/177Hf ratios. The chondritic values of 176Lu/177Hf=0.0336 and 176Hf/177Hf=0.282785, reported by Bouvier et al. (2008),were adopted for the calculation of εHf(t) values (the parts in 104 devia-tion of initial Hf isotope ratios between the zircon sample and the chon-dritic reservoir). The depleted mantle Hf model ages (TDM) werecalculated using the measured 176Lu/177Hf ratios of zircon, based onthe assumption that the depleted mantle reservoir has a linear isotopicgrowth from 176Hf/177Hf=0.279718 at 4.55 Ga to 0.283250 at present,with 176Lu/177Hf=0.0384 (Griffin et al., 2000).

4. Qualifying magma fO2 by using zircon Ce4+/Ce3+ and Eu/Eu*

Zircon is a widespread accessory mineral in intermediate to felsicigneous rocks and is resistant to hydrothermal alteration and physicaland chemical weathering (Hoskin and Schaltegger, 2003; Scherer etal., 2007). And Ce and Eu in zircons commonly are sensitive to mag-matic oxidation state due to multiple ionic states. Qualitative estimateof fO2 using zircon Ce4+/Ce3+ and Eu/Eu* is helpful for decipheringthe fundamental difference of fO2 in our study. Here, we calculate zir-con Ce4+/Ce3+ and Eu/Eu* by the method of Ballard et al. (2002). Thedetailed description of this method is described by Ballard et al.(2002). We summarize the essentials here. We use following equa-tion for the Ce4+/Ce3+ rations in zircon:

Ce4þ=3þzircon ¼

Cemelt− CezirconDzirocn=melt

Ce3þCezircon

Dzirocn=melt

Ce4þ−Cemelt

The concentrations of Ce in zircon is measured directly by in-situchemical analysis of zircon using LA-ICP-MS, and melt value isassumed to be equivalent to the whole-rock (as a proxy for melt) con-centration of Ce. The partition coefficients for Ce4+ and Ce3+ can beestimated on the basis of crystal chemical constraints on trace-element partitioning of the middle-heavy REEs (Sm, Dy, and Lu), Zrand Th between zircon and whole rock (Blundy and Wood, 1994).The trace elements' partition coefficients were available here becauseall the samples we analyzed are fresh, and the whole rock Th, Zr andREE contents of adakites we studied here fall in the same ranges (Liuet al., 2010). Thus, the calculated Ce4+/Ce3+ ratios are available inthis study.

Both zircons Eu3+/Eu2+ and Ce4+/Ce3+ are controlled by themagma fO2. However, compared to zircon Ce4+/Ce3+, we cannot calcu-late zircon Eu3+/Eu2+ by themethod of Ballard et al. (2002) because di-valent ion Eu2+ is not compatible in zircon, and few divalent ions couldbe easily incorporated too. Thus, only Eu/Eu*s were calculated in thisstudy.

It is noted that the calculation of Ce4+/Ce3+ ratios is not affectedby fractionation of LREE-enriched phases such as xenotime and mon-azite, because it is based on zircon-melt partitioning of REEs. ZirconCe4+/Ce3+ ratios greater than one do not imply the same for theparental melt (Ballard et al., 2002). A positive Ce anomaly in zirconis consistent with crystallization from a melt with a Ce4+/Ce3+

ratio on the order of 10–3. Mass-balance considerations indicate thatfractional crystallization or accumulation of zircon is incapable ofgenerating measurable Ce anomalies in magmas (Ballard et al.,2002). It is proved by the fact that the whole rock geochemistry ofadakites from the LYRB and STLF has similar REE patterns with almost

indistinguishable Ce and Eu anomalies, but they have dramaticallydifferent zircon Ce4+/Ce3+ and Eu/Eu*.

5. Results

In-situ zircon oxygen and hafnium isotopes, calculated Ce4+/Ce3+,Eu/Eu*, and Ti-in-zircon temperatures are listed in Table 1. Zircon206Pb/238U ages obtained in the same analysis spots are also shown inTable 1. The original zircon U–Pb, Lu–Hf isotopes and trace elementsare available in Supplementary Table S1, Table S2 and Table S3. TheTi-in-zircon temperatures were calculated from Ti concentrations inzircon using the thermometry calibrated by experiments (Watsonand Harrison, 2005; Watson et al., 2006).

5.1. Zircon U–Pb ages

Zircons from the STLF are generally prismatic or broken prisms,colorless, transparent, and euhedral, up to ~100 μm in length, withlength to width ratios of about 1:1–2:1. They are characterized bypatchy CL images (Fig. 2); a few grains show broad euhedral concen-tric zoning. U contents range from 37 to 118 ppm, and Th from 35 to130 ppm. Th/U ratios range from 0.3 to 2.1. All the measured spotsfrom the STLF fall on the concordant line within analytical errors(Fig. 2). In detail, the weighted mean206Pb/238U ages for Damaocun,Fangjiangzhuang and Qiaotouji intrusions are 132.3±1.9 Ma (n=16,2σ), 133.5±1.7 Ma (n=12, 2σ) and 136.0±2.5 Ma (n=11, 2σ),respectively. Zircon dating results and CL images did not reveal anyinherited zircons in any of the three intrusions (Fig. 2). Comparingwith the SIMS U–Pb ages reported by Liu et al. (2010) in the same sam-ples, LA-ICPMS ages obtained here are systematically older by 4–5 Ma,whichmay be related to Pb surface contamination linked to preparationof samples (Paul et al., 2011). Despite slight discrepancy between thesetwomethods, this does not significantly influence the results and inter-pretations of this study because highly precise ages are not a necessityfor zircon Hf (zircon having very low Lu/Hf) and O isotopes and traceelements study. No inherited zircons of old ages have been found forthe analyzed zircons from the STLF, consistent with the results of Liuet al. (2010).

Zircons from the LYRB are subdivided into two groups: long col-umn (TGS-7-1 and TGS-7-2) and short column (TLS01, FS07 andWS02). Most zircons from Tongguanshan are long column, colorless,transparent, and euhedral, mostly ~100 μm in length, with aspectratios of about 2:1–5:1. Euhedral concentric zoning is commonlyobserved under CL (Fig. 2). Concentrations of U range from 124 to693 ppm, and Th from 66 to 597 ppm. Th/U ratios range from 0.4 to1.2. No inherited core was observed, but several inherited zirconswere found, with euhedral concentric zoning and Th/U ratiosfrom 0.1 to 0.7. The weighted mean206Pb/238U ages for the twoTongguanshan samples are 140.2±6.2 Ma (n=9,2σ) and 136.2±1.6 Ma (n=14,2σ), respectively, which are similar within error.Two samples from Tongguanshan contain 6 inherited zircons, withconcordant ages ranging from 1849 to 2086 Ma.

Zircon from Tonglushan, Fengshan and Wushan porphyries arerelatively short columner, colorless, transparent and euhedral, mostly~100 μm in length, with aspect ratio of about 1:1–2:1. Euhedral con-centric zoning is common (Fig. 2). Concentrations of U range from 23to 103 ppm, and Th from 9 to 150 ppm. Th/U ratios range from 0.4 to2.1. No inherited core was observed, but several inherited zirconswere found, with euhedral concentric zoning and Th/U ratios from0.3 to 1.8. The weighted mean 206Pb/238U age of TLS01, FS07 andWS02 are138.4±1.6Ma (n=19, 2σ), 145.1±2.6Ma (n=15, 2σ)and 141.9±2.9 Ma (n=11, 2σ), respectively. Seven inherited zirconsfrom these three samples were found with concordant ages rangingfrom 895 to 2395 Ma.

In summary, ages obtained here are similar to previously reportedages (140±5 Ma) for ore-bearing intrusions from the LYRB (Li et al.,

Table 1In-situ zircon Hf–O isotopic compositions, Ce4+/Ce3+and Eu/Eu* ratios, and Ti-in-zircon temperatures for the LYRB and STLF adakites.

Spot no. Ages δ18OZrc 2s δ18OWR Ce4+/Ce3+ Eu/Eu* TTi-in-zrc(°C)

176Yb/177Hf 176Lu/177Hf 176Hf/177Hf Hf(t) TDM2

(Ga)

STLFDMC-1

DMC-1.S01 130 6.7 0.3 7.81 16 0.37 805 0.019028 0.000694 0.282080 −21.7 2.2DMC-1.S03 131 6.3 0.2 7.43 58 0.40 796 0.009671 0.000357 0.281943 −26.5 2.5DMC-1.S04 129 6.2 0.3 7.32 29 0.37 811 – – – –

DMC-1.S05 128 6.5 0.3 7.62 20 0.39 799 0.013107 0.000476 0.282027 −23.6 2.3DMC-1.S06 130 6.5 0.2 7.66 17 0.38 820 0.018913 0.000684 0.282037 −23.2 2.3DMC-1.S07 127 5.8 0.2 6.94 23 0.42 794 0.010019 0.000361 0.281923 −27.3 2.5DMC-1.S08 138 6.3 0.2 7.45 41 0.38 783 0.010513 0.000393 0.282055 −22.4 2.2DMC-1.S09 137 6.1 0.2 7.19 47 0.37 795 0.008989 0.000339 0.282074 −21.7 2.2DMC-1.S10 134 6.0 0.2 7.11 42 0.40 779 0.013727 0.000503 0.282000 −24.4 2.3DMC-1.S11 132 6.1 0.3 7.19 31 0.35 800 0.011239 0.000412 0.282088 −21.3 2.1DMC-1.S12 134 6.2 0.2 7.30 40 0.40 771 0.012352 0.000457 0.281987 −24.9 2.4DMC-1.S13 136 6.4 0.2 7.49 42 0.41 775 0.009745 0.000372 0.282096 −20.9 2.1DMC-1.S14 132 6.1 0.2 7.23 31 0.37 788 0.009554 0.000363 0.282089 −21.3 2.1DMC-1.S16 132 6.0 0.2 7.11 64 0.39 794 0.009186 0.000344 0.282092 −21.2 2.1DMC-1.S18 131 6.1 0.2 7.18 119 0.41 757 0.010000 0.000372 0.281947 −26.4 2.4DMC-1.S19 137 6.1 0.2 7.21 176 0.43 754 0.009062 0.000340 0.282102 −20.7 2.1DMC-1.S02 125 6.6 0.2 7.71 – – – 0.005938 0.000228 0.281863 −28.8 2.6DMC-1.S15 126 6.3 0.3 7.37 – – – 0.006384 0.000247 0.282042 −23.5 2.2DMC-1.S17 130 5.7 0.2 6.82 – – – 0.009640 0.000367 0.281978 −25.7 2.4DMC-1.S20 127 5.8 0.3 6.96 – – – – – – – –

DMC-1.S21 132 5.9 0.1 6.97 – – – – – – – –

DMC-1.S22 127 5.9 0.3 7.00 – – – – – – – –

DMC-1.S23 126 6.3 0.3 7.42 – – – – – – – –

FJZ-1FJZ-1.S01 134 6.2 0.4 7.36 17 0.36 751 0.018574 0.000684 0.282220 −16.6 1.8FJZ-1.S03 131 6.4 0.3 7.60 20 0.38 795 0.015872 0.000578 0.282071 −22.0 2.2FJZ-1.S04 136 6.2 0.4 7.43 87 0.35 749 0.010153 0.000384 0.282077 −21.6 2.2FJZ-1.S05 131 6.2 0.3 7.39 35 0.43 788 0.011212 0.000423 0.282177 −18.2 1.9FJZ-1.S06 134 5.9 0.3 7.05 119 0.39 769 0.009618 0.000367 0.282096 −21.0 2.1FJZ-1.S08 138 5.8 0.3 7.02 29 0.37 787 0.011584 0.000433 0.282003 −24.2 2.3FJZ-1.S09 134 5.6 0.3 6.77 109 0.37 773 0.009387 0.000356 0.282107 −20.6 2.1FJZ-1.S10 129 5.9 0.2 7.10 22 0.38 792 0.015739 0.000579 0.282230 −16.4 1.8FJZ-1.S11 134 5.7 0.3 6.86 133 0.33 750 0.010885 0.000411 0.282060 −22.3 2.2FJZ-1.S12 132 5.6 0.3 6.80 35 0.35 766 0.017281 0.000631 0.282148 −19.2 2.0FJZ-1.S14 137 6.1 0.2 7.34 24 0.40 778 0.018507 0.000678 0.282128 −19.9 2.1FJZ-1.S15 134 5.8 0.2 7.00 228 0.31 748 0.009262 0.000354 0.282122 −20.1 2.1FJZ-1.S02 130 6.5 0.3 7.71 – – – 0.007895 0.000301 0.282131 −20.0 2.0FJZ-1.FS07 127 5.7 0.3 6.93 – – – 0.014280 0.000551 0.282158 −18.9 2.0FJZ-1.S13 127 5.8 0.3 7.00 – – – 0.006590 0.000254 0.282051 −22.7 2.2

QTJ-2QTJ-2.S01 136 6.1 0.3 7.01 208 0.56 740 0.008468 0.000321 0.282107 −20.5 2.1QTJ-2.S02 133 6.0 0.2 6.99 107 0.61 755 0.008927 0.000339 0.282136 −19.6 2.0QTJ-2.S03 136 6.0 0.3 7.00 181 0.57 754 0.008222 0.000310 0.282108 −20.6 2.1QTJ-2.S04 140 6.2 0.3 7.18 110 0.60 730 0.009232 0.000350 0.282050 −22.5 2.2QTJ-2.S05 137 6.0 0.3 6.91 114 0.57 750 0.009512 0.000357 0.282039 −22.9 2.2QTJ-2.S06 135 5.8 0.2 6.80 42 0.57 754 0.012228 0.000449 0.282039 −23.0 2.2QTJ-2.S08 136 6.0 0.3 6.95 259 0.59 754 0.006662 0.000253 0.282046 −22.7 2.2QTJ-2.S09 137 6.0 0.3 6.96 317 0.54 737 0.007182 0.000275 0.282163 −18.6 2.0QTJ-2.S11 133 5.8 0.3 6.71 201 0.59 751 0.007969 0.000306 0.282166 −18.5 2.0QTJ-2.S15 133 5.6 0.2 6.60 54 0.60 754 0.014508 0.000546 0.282082 −21.5 2.1QTJ-2.S18 138 6.1 0.2 7.08 45 0.57 765 0.013073 0.000487 0.282134 −19.6 2.0QTJ-2.S07 129 6.0 0.3 6.92 – – – 0.013512 0.000497 0.282078 −18.9 2.2QTJ-2.S12 130 6.0 0.4 6.99 – – – 0.008163 0.000315 0.282092 −21.1 2.1QTJ-2.S13 – 5.6 0.2 6.56 – – – 0.008872 0.000337 0.282065 −22.1 2.2QTJ-2.S14 – 6.4 0.3 7.39 – – – 0.010945 0.000409 0.282145 −18.9 2.0

LYRBTLS01

TLS01-1 140 6.96 0.37 8.35 167 0.35 0.011814 0.000498 0.282496 −6.7 1.2TLS01-2 144 7.82 0.24 9.22 39 0.62 709 0.010312 0.000438 0.282473 −7.5 1.3TLS01-3 136 7.10 0.31 8.50 103 0.69 0.013885 0.000585 0.282475 −7.5 1.3TLS01-4 144 7.09 0.36 8.49 67 0.46 754 0.013608 0.000565 0.282465 −7.9 1.3TLS01-5 7.30 0.37 8.69 77 0.69 534 0.013360 0.000575 0.282503 −6.5 1.2TLS01-6 141 7.01 0.28 8.40 0.013754 0.000573 0.282475 −7.5 1.3TLS01-7 144 7.15 0.27 8.55 68 0.66 650 0.012927 0.000548 0.282538 −5.3 1.1TLS01-8 139 7.71 0.22 9.11 84 0.70 715 0.021003 0.000876 0.282597 −3.2 1.0TLS01-9 137 6.83 0.28 8.23 205 0.71 635 0.018837 0.000753 0.282508 −6.3 1.2TLS01-10 150 6.98 0.44 8.37 36 0.55 626 0.013007 0.000531 0.282462 −7.9 1.3TLS01-11 143 7.15 0.24 8.55 244 0.54 706 0.015346 0.000657 0.282534 −5.4 1.1TLS01-12 7.52 0.31 8.92 219 0.65 749 0.017304 0.000730 0.282554 −4.7 1.1TLS01-13 7.29 0.29 8.69 99 0.68 709 0.014314 0.000616 0.282522 −5.8 1.2

(continued on next page)


Table 1 (continued)



(Ga)

LYRBTLS01

TLS01-14 131 7.42 0.33 8.81 93 0.47 713 0.016641 0.000702 0.282527 −5.7 1.2TLS01-15 7.21 0.35 8.61 105 0.58 736 0.019311 0.000790 0.282562 −4.4 1.1

FS07FS07-1 1088 7.40 0.33 8.83 61 0.66 727 0.015748 0.000603 0.282291 6.6 1.7FS07-9 447 7.92 0.32 9.35 837 0.009713 0.000411 0.282447 −1.8 1.3FS07-2 7.86 0.36 9.28 1343 0.59 721 0.022235 0.000931 0.282583 −3.7 1.0FS07-3 142 7.75 0.27 9.18 695 0.69 704 0.021845 0.000920 0.282575 −4.0 1.1FS07-4 139 7.40 0.27 8.83 1565 0.54 611 0.016533 0.000751 0.282613 −2.6 1.0FS07-5 7.94 0.32 9.37 332 0.87 648 0.019261 0.000895 0.282551 −4.8 1.1FS07-6 160 8.26 0.29 9.69 806 1.87 0.019773 0.000811 0.282515 −6.1 1.2FS07-7 7.97 0.36 9.40 498 0.59 654 0.019779 0.000838 0.282496 −6.8 1.2FS07-8 150 7.91 0.39 9.34 668 0.56 688 0.033529 0.001306 0.282537 −5.4 1.2FS07-10 8.04 0.32 9.47 2736 0.73 0.018317 0.000837 0.282527 −5.7 1.2FS07-11 142 7.80 0.22 9.23 660 0.51 582 0.012245 0.000534 0.282532 −5.5 1.1FS07-12 7.72 0.43 9.15 705 0.021585 0.000949 0.282562 −4.5 1.1FS07-13 149 8.08 0.27 9.50 860 0.51 0.021795 0.000914 0.282578 −3.9 1.1FS07-14 142 7.39 0.23 8.82 844 0.70 612 0.025470 0.001085 0.282591 −3.4 1.0FS07-15 7.46 0.32 8.89 515 0.60 728 0.031403 0.001245 0.282567 −4.3 1.1

WS02WS02-6 314 7.49 0.28 9.06 111 0.45 0.021862 0.000832 0.282043 −19.1 2.2WS02-10 216 7.02 0.36 8.59 819 0.022840 0.000922 0.282586 −2.0 1.0WS02-3 370 8.21 0.23 9.78 736 0.26 612 0.037804 0.001376 0.282146 −14.3 2.0WS02-14 143 7.74 0.32 9.31 252 0.84 521 0.017878 0.000721 0.281967 −25.5 2.4WS02-1 129 7.94 0.36 9.51 84 0.56 709 0.021625 0.000901 0.282655 −1.1 0.9WS02-2 143 7.70 0.32 9.27 74 0.53 0.019851 0.000779 0.282608 −2.8 1.0WS02-4 141 7.47 0.37 9.04 685 0.52 670 0.018826 0.000806 0.282608 −2.8 1.0WS02-5 151 7.59 0.20 9.16 1318 0.74 599 0.021384 0.000916 0.282691 0.1 0.8WS02-7 143 7.59 0.17 9.16 321 0.82 679 0.021996 0.000954 0.282612 −2.7 1.0WS02-8 148 7.32 0.39 8.89 243 0.51 445 0.021559 0.000911 0.282632 −2.0 0.9WS02-9 139 6.76 0.39 8.33 693 0.59 692 0.025236 0.001091 0.282604 −3.0 1.0WS02-11 143 7.17 0.44 8.74 144 0.57 0.010793 0.000484 0.282591 −3.4 1.0WS02-12 146 7.26 0.28 8.83 255 0.65 0.018458 0.000809 0.282604 −3.0 1.0WS02-13 143 7.19 0.25 8.76 788 0.60 717 0.018801 0.000770 0.282716 1.0 0.7WS02-15 133 7.05 0.27 8.62 222 0.71 532 0.025313 0.000978 0.282744 2.0 0.7

TGS-7-1TGS-7-1.S02 132 6.6 0.3 7.93 326 0.66 681 0.025214 0.000990 0.282334 −12.7 1.6TGS-7-1.S04 160 6.3 0.4 7.65 164 0.72 966 0.022636 0.000895 0.282188 −17.2 1.9TGS-7-1.S05 146 6.1 0.2 7.48 233 1.04 659 0.017482 0.000774 0.282364 −11.3 1.5TGS-7-1.S06 143 5.8 0.2 7.11 206 0.68 685 0.030155 0.001173 0.282303 −13.6 1.7TGS-7-1.S08 148 4.7 0.3 6.06 239 0.61 683 – – – – –

TGS-7-1.S12 139 6.4 0.4 7.72 87 0.80 681 0.034452 0.001283 0.282312 −13.3 1.7TGS-7-1.S15 134 6.5 0.2 7.82 100 0.69 681 0.022926 0.000879 0.282401 −10.3 1.4TGS-7-1.S19 142 6.6 0.3 7.89 311 0.72 668 0.019251 0.000801 0.282228 −16.2 1.8TGS-7-1.S22 143 7.0 0.3 8.36 335 0.65 679 0.018136 0.000746 0.282283 −14.2 1.7TGS-7-1.S03 2147 7.8 0.2 9.13 722 0.013672 0.000483 0.281297 −4.9 3.9TGS-7-1.S07 – 4.9 0.4 6.20 – – – 0.045946 0.001852 0.282327 1.6 1.6TGS-7-1.S09 2410 7.0 0.2 8.37 722 0.026082 0.000900 0.281105 −6.5 4.3TGS-7-1.S10 - 6.7 0.3 7.99 – – – 0.011411 0.000440 0.282334 −5.0 1.6TGS-7-1.S11 – 7.0 0.3 8.35 – – – – – – – –

TGS-7-1.S13 – 7.1 0.2 8.47 – – – 0.036060 0.001262 0.282191 −11.4 1.9TGS-7-1.S14 – 7.0 0.3 8.32 – – – – – – – –

TGS-7-1.S16 – 6.1 0.2 7.44 – – – 0.017917 0.000722 0.282252 −15.4 1.8TGS-7-1.S17 – 7.1 0.3 8.44 – – – 0.023201 0.000925 0.282319 −12.9 1.6TGS-7-1.S18 – 6.2 0.3 7.50 – – – – – – – –

TGS-7-1.S20 – 6.8 0.3 8.13 – – – 0.025986 0.001050 0.282319 −8.2 1.6TGS-7-1.S21 – 5.9 0.3 7.27 – – – 0.024014 0.000990 0.282437 −9.0 1.4

TGS-7-2TGS-7-2.S03 140 8.0 0.3 9.37 590 0.77 655 0.030485 0.001183 0.282251 −15.5 1.8TGS-7-2.S06 138 7.0 0.3 8.33 579 0.72 640 0.020142 0.000795 0.282313 −13.3 1.6TGS-7-2.S09 137 7.1 0.3 8.42 673 0.015280 0.000651 0.282443 −8.7 1.3TGS-7-2.S12 138 7.5 0.2 8.80 363 0.68 – 0.026595 0.001023 0.282221 −16.6 1.9TGS-7-2.S13 138 8.5 0.3 9.88 191 0.61 660 0.021870 0.000822 0.282264 −15.0 1.8TGS-7-2.S14 134 7.4 0.2 8.76 149 0.76 684 0.027578 0.001063 0.282379 −11.0 1.5TGS-7-2.S16 137 8.4 0.3 9.71 423 0.70 647 0.016580 0.000655 0.282311 −13.4 1.6TGS-7-2.S20 134 7.1 0.3 8.39 174 0.69 684 0.017671 0.000658 0.282320 −13.1 1.6TGS-7-2.S23 133 6.7 0.3 8.07 240 0.81 841 0.020208 0.000765 0.282408 −10.0 1.4TGS-7-2.S01 1876 6.6 0.2 7.93 783 0.000161 0.000006 0.280978 −21.7 4.5TGS-7-2.S02 1966 14.1 0.2 15.45 782 0.000229 0.000007 0.281044 −17.4 4.4TGS-7-2.S04 2086 14.4 0.2 15.74 0 0.05 872 0.001361 0.000039 0.281388 −2.4 3.7TGS-7-2.S05 137 6.5 0.2 7.87 – – – 0.032515 0.001176 0.282478 −7.4 1.3TGS-7-2.S07 2012 6.2 0.3 7.54 806 0.006468 0.000228 0.281029 −17.1 4.4TGS-7-2.S08 133 9.6 0.6 10.94 – – – 0.016735 0.000658 0.282469 −10.7 1.3TGS-7-2.S10 – 7.3 0.4 8.65 – – – 0.020072 0.000762 0.282356 −14.7 1.5TGS-7-2.S11 – 8.9 0.3 10.27 – – – – – – – –


Table 1 (continued)



(Ga)

TGS-7-2TGS-7-2.S15 – 6.7 0.3 8.02 – – – 0.020907 0.000769 0.282312 −16.3 1.6TGS-7-2.S17 – 6.9 0.2 8.29 – – – 0.015357 0.000592 0.282291 −17.0 1.7TGS-7-2.S18 – 7.4 0.2 8.74 – – – 0.017462 0.000680 0.282276 −17.5 1.7TGS-7-2.S19 – 6.3 0.2 7.60 – – – 0.025319 0.000942 0.282401 −13.1 1.5TGS-7-2.S21 - 7.2 0.2 8.54 – – – 0.014330 0.000560 0.282298 −16.8 1.7TGS-7-2.S22 – 7.1 0.2 8.45 – – – 0.015315 0.000583 0.282255 −18.3 1.7

Notes: bold and italic ages are dated by SIMS; “–” means no data available according three criteria: (1) any trace elements signals show obvious fluctuation (>3times of normalsignal), which maybe fluid inclusions, are excluded; (2) high Yb/Hf (>0.05) ratios are excluded; (3) concordance of the zircon ages below 85% are excluded. T(°C) representsTi-in-zircon temperature calculated from Ti contents in zircon based on the method of Watson et al. (2006); Ce4+/Ce3+ and Eu/Eu* are calculated with the method by Ballardet al. (2002).


2009a, 2010b; Wang et al., 2006; Wu et al., 2012; Xie et al., 2008b,2011a,b). Thirteen out of total 57 dated zircons were found to beolder than the rest in the five analyzed samples from the LYRB.These wide age-range inherited ancient zircons from LYRB adakitesmay indicate sediments involvements in magma sources.

5.2. Zircon Hf isotopes

Zircons from the Damaocun, Fangjiangzhuang and Qiaotouji plutonsin the STLF have 176Hf/177Hf varying from 0.281923 to 0.282102,0.282003 to 0.282230 and 0.282039 to 0.282166, respectively. The zirconεHf(t) values, which were corrected to the crystallization time (LateJurassic to Early Cretaceous) based on the weighted mean 206Pb/238Uages of each pluton, are −27.3 to −20.7, −16.4 to −24.2 and −18.5to −23.0, respectively (Table 1; Fig. 3). The corresponding two-stageHf model ages are 2.1 to 2.6 Ga, 1.8 to 2.3 Ga, and 2.0 to 2.2 Ga respec-tively (Fig. 3).

Zircons from the Tonglushan, Fengshandong, Wushan andTongguanshan diorites in the LYRB show significantly variable Hfisotopic compositions with 176Hf/177Hf varying from 0.282462 to0.282597, from 0.282291 to 0.282613, from 0.281967 to 0.282744and from 0.281297 to 0.282478, respectively. The zircon εHf(t) valuesare −7.9 to −3.2, −6.8 to −2.6, −3.4 to 2.0 and −17.2 to −8.7,respectively. The corresponding two-stage Hf model ages are 1.0 to1.3 Ga, 1.0 to 1.2 Ga, 0.7 to 2.4 Ga and 1.3 to 1.9 Ga, respectively(Table 1; Fig. 3).

5.3. Zircon oxygen isotopes

Zircon oxygen isotopic compositions from the STLF Damaocun,Fangjiangzhuang and Qiaotouji plutons are relatively homogeneous,with δ18O=5.8–6.7‰ (n=16), 5.6–6.4‰ (n=12) and 5.6–6.4‰(n=11), respectively (Table 1). The weighted mean δ18O of all zirconsfrom the STLF is 6.0±0.5‰ (2SD; n=39). In contrast, oxygen isoto-pic compositions of magmatic zircons from the LYRB Tonglushan,Fengshandong, Wushan and Tongguanshan plutons are highly het-erogeneous, with a wide range of δ18O from 6.8 to 7.8‰ (n=15),from 7.4 to 8.3‰ (n=13), from 6.8 to 7.9‰ (n=12) and from 4.7to 8.9‰ (n=36), respectively. In summary, zircon oxygen isotopiccompositions from the STLF are relatively homogenous, whereasthose from the LYRB have highly heterogeneous and obviouslyheavier δ18O values compared to the STLF (Figs. 4 and 5).

5.4. Zircon trace elements

Zircons from the STLF plutons are prominently enriched in heavy rareearth elements (HREE) relative to light REE (LREE), with positive Ce andnegative Eu anomalies (Fig. 6), which are common features of magmaticzircons in igneous rocks (Hoskin and Schaltegger, 2003). The (Yb/Lu)Nratios in zircons from the STLF are 0.90–0.99. The La, Nb and U contents

in zircon from the STLF are mostly below 0.05 ppm (exceptspot DMC-1.s14, 0.25 ppm and FJS-1.s8, 0.21 ppm), 0.48–0.92 ppm(0.62 ppm in average) and 37.3–117.8 ppm (69 ppm in average),respectively. The calculated zircon Ce4+/Ce3+ varies from 16 to 317(avg. 84; n=39) and Eu/Eu* varies from 0.31 to 0.61 (avg. 0.44; n=39)(Fig. 7).

Zircons from the LYRB plutons are also enriched in HREEs relativeto LREEs, but they have relatively higher HREEs contents and weakernegative Eu anomalies than zircons from the STLF plutons (Fig. 6).The zircon (Yb/Lu)N from the LYRB are 0.58 to 0.79. The La, Nb,and U contents in zircons from the LYRB are ≤1.8ppm (mostlyhigher than 0.1 ppm), 1.06–7.24 ppm (2.9 ppm in average) and 84–957 ppm (314 ppm in average), respectively, which are relativelyhigher than those from the STLF. The calculated Ce4+/Ce3+ variesfrom 36 to 2736 (avg. 417; n=55) and Eu/Eu* varies from 0.35to1.87 (avg. 0.67; n=55).

In summary, the trace element concentrations and calculatedCe4+/Ce3+ with Eu/Eu* in zircons from the LYRB are obviously higherthan those from the STLF.

5.5. Ti-in-zircon temperatures

Titanium content in zircon is controlled by zircon forming tempera-ture. The Ti-in-zircon thermometer has been widely used to identifymagma forming or metamorphism temperatures (Watson and Harrison,2005; Watson et al., 2006). Ti-in-zircon temperatures range from 754 to820 °C (789±36 °C, 2SD, n=16) in Damaocun, 748 to 795 °C (770±36 °C, 2SD, n=12) in Fangjiangzhuang and 730 to 765 °C (749±20 °C,2SD, n=11) in Qiaotouji from the STLF, which are systematically higherthan those from the LYRB, e.g., Tonglushan (534 to 754 °C, 686±127 °C, 2SD, n=12), Fengshandong (582 to 837 °C, 665±103 °C, 2SD,n=10), Wushan (445 to 819 °C, 618±213 °C, 2SD, n=11) andTongguanshan (640 to 966 °C, 671±150 °C, 2SD, n=15) (Fig. 8).

6. Discussion

In this section, we first evaluate the zircon oxybarometry methodsby different authors, and then use zircon Hf–O isotopic data and zircontrace elements to constrain the petrogenesis of the STLF ore-barren plu-tons and the LYRB ore-bearing plutons. Using the calculated zirconCe4+/Ce3+ with Eu/Eu*, we then discuss the difference in fO2 and fac-tors controlling the related Cu–Au mineralization.

6.1. Comparative studies of zircon oxybarometry by zircon Ce and Eucontents.

To date, several approaches have been done to estimate the appli-cation of zircon as an oxybarometry based on Ce and Eu contents.Qualitative estimate of fO2 based on zircon-melt partitions of REEsand Th–Zr was carried out by Ballard et al. (2002). Takahashi et al.

0.018

0.019

0.020

0.021

0.022

0.023

0.024

0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22

120

130

140

150

133.5±1.7 MaMSWD = 0.48;n=12

FJZ-1

0.017

0.019

0.021

0.023

0.025

0.06 0.10 0.14 0.18 0.22

110

130

150

132.3±1.9 MaMSWD= 0.72;n=16

DMC-1

0.018

0.020

0.022

0.024

0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22

120

130

140

150

136.0±2.5 MaMSWD = 0.21;n=11

QTJ-2

0.0185

0.0195

0.0205

0.0215

0.0225

0.0235

0.06 0.10 0.14 0.18 0.22

120

130

140

150

136.2±1.6 MaMSWD =0.49;n=14

TGS-7-2

0.018

0.020

0.022

0.024

0.026

0.028

0.0 0.2 0.4 0.6 0.8 1.0

13

01

50

Intercepts at 132.4±3.3Ma

MSWD = 0.54;n=9

TGS-7-1

207Pb/235U

206 P

b/23

8 U

130/6.7/-23.2

134/6.0/-24.4 134/5.9

/-21.0138/5.8/-24.2

135/5.8/-23.0

136/6.0/-22.7

2147/7.9/-4.9

132/6.6/-12.7

140/8.0/-15.5

1966/14.1/-17.4

0.018

0.020

0.022

0.024

0.026

0.028

0.06 0.10 0.14 0.18 0.22

130

150

170

145.1±2.6 MaMSWD =1.7;n=15

FS07142/7.8/-4.0

1088/7.4/6.6

0.017

0.019

0.021

0.023

0.025

0.027

0.08 0.10 0.12 0.14 0.16 0.18 0.20

120

140

160

141.9±2.9 MaMSWD =0.8;n=11

WS022518Ma

7/6( Pb)

143/7.7/-2.8

0.017

0.019

0.021

0.023

0.025

0.027

0.11 0.13 0.15 0.17 0.19

120

140

160

TLS01

138.4±1.6 MaMSWD =2.5;n=19

140/7.0/-6.7

139/7.7/-3.2



(2003) applied Ce LIII-edge XANES (X-ray absorption near-edge struc-ture) to determine zircon Ce4+/Ce3+ directly. Trail et al. (2011)experimentally calibrated the relationship between zircon Ce/Ce*(Ce*=(LaN×PrN)1/2) and fO2. Recently, Burnham and Berry (2012)also conducted an experimental study demonstrating that the parti-tion coefficients (Di) of Ce and Eu between zircon and melt vary sys-tematically with fO2.

Direct determination of zircon Ce4+/Ce3+ by spectroscopicmethods is difficult, as γ-irradiation experiments suggest that zirconCe4+ was easily reduced by radiation effect due to U–Th in the zircon(Takahashi et al., 2003). The experimental calibration of Trail et al.(2011) has some unconformities when this method was used in ourstudy. Precisely determining La, Ce and Pr contents is very importantfor direct determination of zircon Ce4+/Ce3+. However, many factorscould influence the LREE determination of zircons. (1) The calculationof Ce/Ce* based on La and Pr contents sometimes is incorrect, becausezircon commonly has very low contents of La and Pr (sometimesbelow detection limit). Thus the calculated Ce/Ce*may not really reflectthe true fO2 when zircon crystallized. (2) Tiny fluid/melt/apatite inclu-sions in zircon may affect determination of La contents. Since the similarP contents of zircons from the LYRB and STLF (Fig. 6B) and apatite cannotchange U contents of zircon (Fig. 6C), apatite inclusions were excludedhere as a cause for the highly variable La content. Instead, this maycome from tiny fluid/melt inclusion in zircon from the LYRB (Hoskinand Schaltegger, 2003). Thus, zircon oxybarometry calculated by usingLa–Ce–Pr contents, is not an effectivemethod to study the fO2 ofmagmas.Indeed, according to the relationship between zircon Ce/Ce* and fO2 byTrail et al. (2011), we got an unrealistic fO2 of the STLF plutons whichare ~5 log units above FMQ (fayalite-magnetite-quartz) (Table S3).

Using the linear correlation between logDCe, logDEu (D: partitioncoefficient between zircon and melt) and fO2 is an alternativeapproach to obtain the redox state of magma quantitatively (Burnhamand Berry, 2012). However, similar to the method of Trail et al.(2011), we still got an unrealistic fO2 of the STLF plutons about 4–6 logunits above FMQ (Table S1). Although absolute fO2 values calculated bythe method of Burnham and Berry (2012) yielded unrealistically highresults, a significant relative difference of fO2 was obtained between plu-tons from the LYRB and STLF. Systematically, plutons from the LYRB havefO2 about two log units higher than those from the STLF. In detail, zirconfrom the LYRB have an average fO2 of ~FMQ+7 (DCe) and ~FMQ+5(DEu), compared to zircons from the STLF of ~FMQ+5 (DCe) and~FMQ+3 (DEu) (Table S3).

Contrasting to the method of Trail et al. (2011) and Burnham andBerry (2012), the qualitatively oxybarometry by zircon Ce4+/Ce3+

calculated by the method of Ballard et al. (2002) is more available todate. Moreover, qualitative estimate of fO2 using zircon Ce4+/Ce3+

and Eu/Eu* is still helpful for deciphering the fundamental differenceof fO2 in our study. Using this method, the obtained Ce4+/Ce3+ andEu/Eu* show higher fO2 for the LYRB adakites than the STLF adakiticrocks, similar to the results calculated by the method of Burnham andBerry (2012).

6.2. New constraints on origins of the LYRB and STLF adakites from zirconHf–O isotopes and trace elements.

High Sr/Y adakitic rocks widely outcrop in central-eastern China,and only those scattered along the LYRB are ore-bearing whereasthe others are ore-barren. Petrogenesis of adakitic rocks in theDabie Mountain and the STLF were generally regarded as a result ofmelting of thickened LCC and delaminated LCC, respectively (He etal., 2011; Huang et al., 2007, 2008; Li et al., 2012a; Liu et al., 2010;Wang et al., 2007a). However, the petrogenesis of the LYRB adakitic

Fig. 2. Concordia diagrams of zircon U–Pb ages analyzed by LA-ICPMS techniques and repregether with LA-ICPMS (SIMS) 206Pb/238U ages (Ma), δ18O values (in‰)/εHf(t) values. Black celements analyses. Data are reported in Supplementary Table S1.

rocks is highly debated. Existing models include partial melting ofthickened or delaminated LCC (Wang et al., 2004a,b, 2006; Xu et al.,2002; Zhang et al., 2001), fractional crystallization of enrichedmantle-derived basaltic/dioritic magmas coupled with contaminationof crustal materials (Li et al., 2009a; Xie et al., 2008a, 2011a,b), andpartial melting of subducting basaltic oceanic crust (Ling et al.,2009, 2011; Liu et al., 2010).

Adakitic rocks in the STLF and LYRB are almost contemporaneous-ly intruded into the Yangtze block. The whole rock geochemistry sug-gests that the LYRB ore-bearing adakites have an oceanic slab meltaffinity, while the STLF ore-barren high Mg# adakitic rocks werederived from the delaminated LCC (Liu et al., 2010). However, thecritical deficiency to the interpretation of petrogenesis is hydrother-mal alteration of the mineralized plutons, which affected the bulkchemical and isotopic compositions. Here, our new zircon Hf–O iso-tope compositions provide further constrains on the petrogenesis ofadakites from the LYRB by working on a detailed comparison withthe STLF adakites.

The zircon Hf isotope compositions of the LYRB and STLF adakitesare significantly different (Fig. 3). Zircon εHf(t) values of the STLFadakites range from −16 to −28, with a peak at −21, significantlylower than zircon εHf(t) values (from −25 to +2) of the LYRBadakites reinforcing the difference in whole-rock Nd isotopic compo-sitions of the LYRB and STLF adakites (Fig. 3) (Liu et al., 2010). The zir-con Hf model ages (TDM2) of the STLF adakitic rocks are peaked at~2.2 Ga, close to the crust reworking age of the Yangtze Craton of~1.95 Ga and ~2.95 Ga (Fig. 3) (Zhang et al., 2006b), supporting theaffinity of magma source from the Yangtze LCC. The results thus con-firm derivation of the STLF adakitic rocks from the delaminated LCC ofYangtze Block that were interacted with the asthenosphere mantleproducing high Mg# of >50 (Liu et al., 2010). In contrast, the LYRBadakites have a wide range of TDM2 (Hf) from 0.7 to 2.4 Ga, andmost of them are younger than the cratonization time of the YangtzeCraton (Fig. 3). Given that the STLF and LYRB are tectonically locatedin the Yangtze Block (Fig. 1), their different whole-rock Sr–Nd–Pb(Liu et al., 2010) and zircon Hf isotope compositions (this study)argue against the conclusion that the LYRB adakites were formed bypartial melting of the LCC of Yangtze Craton.

In addition, our new in-situ zircon O and Hf isotope data providestrong evidence for involvement of sediments in the origin of the LYRBadakites. The Hf–O isotope correlations (Fig. 9) could be reasonablyexplained as the mixing of subducted oceanic crust with sediments. Indetail, zircon δ18O values in STLF adakites are homogeneous with a nar-row range of 5.6‰ to 6.3‰ and an average of 6.0±0.5‰ (2σ) (Fig. 4),similar to, the mantle δ18O value of zircon (5.3±0.6‰; 2σ; Valley etal., 1998). Such mantle-like δ18O in the STLF adakites was unlikely dueto sediments addition, consistent with the notion obtained from theirun-radiogenic Pb isotopic compositions (e.g., 206Pb/204Pbib16.4; Liu etal., 2010). Instead, it is similar to global metabasaltic granulite xenoliths(δ18O=5.4 to 9.1‰) of mafic to intermediate composition but lighterthan that of lower crustal metasediments (Fig. 5) (Kempton andHarmon, 1992).

In sharp contrast, δ18O values of zircons from LYRB adakites havemuch wider range from 4.7 to 9.6‰ in total despite being relativelyhomogeneous in a single sample (e.g. TLS01 is 6.8–7.8‰, and FS07is 7.4–8.3‰). The whole-rock values calculated based on the formulaof Δ18OZrc-WR=δ18OZrc-δ18OWR≈−0.0612(wt.%SiO2)+2.5 (Valleyet al., 2005) range from 6.1 to 11.4, which are similar to previouslyreported whole-rock δ18O values (8.7–10.9‰; Chen et al., 1993) ofthe LYRB adakites.

Thus, the highly variable oxygen isotopic compositions of theLYRB adakites may be related to mixing between an igneous member

sentative zircon images from the LYRB and STLF. Circles denote the analytical spots, to-ircles represent spots of O–Hf isotopes and white circles are for U–Pb dating and trace

STLF

-3 0 -2 5 -2 0 -1 5 -1 0 -5 0 50

2

4

6

8

1 0

1 2

1 4

1 6

LYRB

Num

ber

0 1 2 30

5

1 0

1 5

2 0 STLF

LYRB

εHf (t)

T (Nd)DM2 (Ga)

T (Hf)DM2 (Ga)

εNd (t)

Num

ber

- 3 0 -2 5 -2 0 -1 5 -1 0 -5 0 50

5

1 0

1 5

2 0

2 5

0 1 2 30

5

1 0

1 5

2 0

2 5 Cratonization time of Yangtze craton

Fig. 3. In-situ zircon Hf and whole rock Nd isotopic compositions of Mesozoic adakitic rocks from the LYRB and STLF in central-eastern China. The whole rock Nd isotope data arefrom Liu et al. (2010) and references therein. The vertical gray bars represent the main cratonlization time of Yangtze block (Zhang et al., 2006a,b). Data are reported in Table 1 andSupplementary Table S2.


with mantle-like δ18O values and sediments that are characterized byheavy δ18O values ranging from ~10 to 40‰ (Hoefs, 2009). The possi-ble source for the igneous member is the asthenosphere mantle oroceanic basaltic crust (MORB), both of which have depleted Hf isoto-pic compositions (e.g., positive εHf(t)) required to produce positiveεHf(t) values of some LYRB samples (Fig. 3). We considered the igne-ous member to be oceanic basaltic crust because direct partial melt-ing of the asthenosphere mantle peridotites cannot generate the

0

10

20

30

40

Num

ber

0

5

10

15

20

25

30

Num

ber

6 7 8 9 10

δ18Ozrc

54.5

6 7 8 9 1054.5

LYRB STLF

Fig. 4. In-situ oxygen isotopic compositions of Mesozoic adakitic rocks from the LYRBand STLF. The vertical gray bars represent the normal-mantle δ18Ozrc range. Data arereported in Table 1.

andesitic to rhyolitic compositions (SiO2>56 wt.%) of the LYRBadakites. Some studies have shown that sediments could be meltedduring subduction and the partial melts (fluids) could be thenmixed (add) with partial melts of basaltic oceanic crust to generatehydrous adakitic magmas (e.g., Bernard et al., 1996; Borisova et al.,2006). However, the proportion of sediments involved in generationof subduction zone adakites was generally not as high as in theLYRB adakites as suggested by distinctly heavier oxygen and enrichedSr–Nd isotopic compositions (87Sr/86Sri>0.7045 and εNd(t)b0) ofthe LYRB adakites relative to modern adakites from subductionzones. Simple binary mixing of the marine sediments and MORBshows that assimilation of 10–20% marine sediments into MORB cangenerate the Hf–O isotopic array of adakites in the LYRB (Fig. 9).

WR

Fig. 5. Integrated oxygen isotopes reservoir of the Earth. Whole rock oxygen iso-tope from LYRB and STLF are calculated from δ18Ozrc according to: Δ18OZrc-WR=δ18OZrc-δ18OWR≈−0.0612 (wt.%SiO2)+2.5(Valley et al., 2005). Oxygen isotopes oflower continental granulite xenoliths are from Kempton and Harmon (1992), MORB(mid-ocean-ridge basalt); altered oceanic crust are from Muehlenbachs (1986); slabderived adakite are from Bindeman et al. (2005) and sediments are from Hoefs (2009).

A B

C D

Fig. 6. A. Chondrite normalized rare earth element (REE) patterns of zircons from Mesozoic adakitic rocks from the LYRB and STLF. Contrasting zircon P vs La (B), Nb vs U (C) and Luvs (Yb/Lu)N (D) from ore-bearing adakites from the LYRB and ore-barren adakitic rocks from STLF. Data are reported in Supplementary Table S3. The normalized values are from Sunand McDonough (1989).


Therefore, initial magmas of the LYRB adakites may be heterogeneousin terms of chemical and isotopic compositions with addition of var-ious amounts of sediments to their igneous source. Moreover, higherNb and U may be due to CO3

2− enriched component into the source(Fig. 6).

Generally,magmas generated bypartialmelting of a dry sourcewouldhave highermelting temperatures, comparedwithmagmas derived fromaqueous-fluid-rich source. Thus, temperatures of initial magmas from themafic LCC are expected to be higher than those from oceanic slabs. In-deed, Ti-in-zircon temperatures indicate that magmas from the STLFhave obviously higher crystallization temperatures than those from the

A

Fig. 7. Correlation between Ce4+/Ce3+with Eu/Eu* and δ18Ozrc ratios from adakitic rocks freported in Table 1.

LYRB (Fig. 8). There are twopossibleways to lowerdown the solidus tem-peratures of the rocks, decompression or adding fluid into the igneoussystem. Assuming that the pressure for forming the LYRB and STLFadakites are not that different (Liu et al., 2010), the systematically lowerTi-in-zircon temperatures of the LYRB adakites than the STLF adakites(Fig. 8) might suggest a water-rich basaltic source for the LYRB adakitesand a dry LCC source for the STLF adakites. It is consistent with thewhole rock geochemistry that the STLF adakitic rocks have relativelyhigher MgO, Cr, Ni, Mg# and K2O/Na2O than the LYRB adakites at agiven SiO2, which imply that magma sources of the former may havelower water contents and lower viscosity than the later (Liu et al., 2010).

B

rom the LYRB and STLF. (A) δ18Ozrc vs Ce4+/Ce3+; (B) Eu/Eu* vs Ce4+/Ce3+. Data are

Fig. 8. Boxplot of Ti-in-zircon temperatures for adakitc rocks from the LYRB and STLF.The temperatures are calculated based on the method by Watson et al. (2006). Thenumber above each sample represents the average Ti-in-zircon temperature of thissample. The boxes extend from quartile Q=0.25 to quartile Q=0.75. The medianvalue is marked in each box. The lines extending to the left and right of each box delin-eate the minimum and maximum values, respectively. The black box represents themean value.

Fig. 9. δ18OWRvs εHf(t) isotopes plot of the STLF and LYRB. All data are listed in Table 1. Haf-nium isotopes sources include: Chauvel et al. (2008) for MORB and sediments; oxygen iso-topes of MORB and marine sediments are from Hoefs (2009). The compositions of theend-members for mixing calculations are: (1) MORB: 176Hf/177Hf=0.283141,δ18O=5.8‰; (2) marine sediments: 176Hf/177Hf=0.282, δ18O=20‰. The mixingcurves were constructed using different HfMORB/HfSediments elemental ratios from1:30 to 1:1.


Zircons Eu/Eu* further give us a clue about the water content ofmagma. Generally, zircons Eu/Eu* have similar characteristics com-pared to zircons Ce4+/Ce3+ and show positive correlation betweenthem (Ballard et al., 2002), however, our zircon data from the LYRBadakites show different characters. Almost half of Ce4+/Ce3+ dataoverlap each other between LYRB and STLF, while the Eu/Eu* betweenLYRB and STLF are quite distinct (Fig. 7A). This reflects some addition-al effect on Eu/Eu* during zircon formation. In general, zircon Eu/Eu*could be controlled by two factors: (1) redox state of the magma; and(2) crystallization of plagioclase, especially co-crystallizing with zir-con. As suggested in Liu et al. (2010), adakites from the LYRB areenriched in water contents and this could postpone the crystallizationof plagioclase (Grove et al., 2003). Therefore, the high zircon Eu/Eu*in the LYRB adakites could be explained by high water contents intheir magma sources. This is consistent with the lower magmatictemperatures (as shown by Ti-in-zircon thermometry) and wholerock geochemistry.

6.3. Implications for the genetic links of adakites with Cu–Au mineralization

The high fO2 of mantle due to subduction related processes iswidely held to Cu–Au porphyry mineralization because breakdownof mantle sulfide minerals and liberation of copper and gold requirehigh fO2 (McInnes et al., 2001; Sillitoe, 1997). This is supported byempirical association between porphyry Cu–Au deposits and adakiticintrusions in subduction zones around the world (e.g. Oyarzun et al.,2001; Reich et al., 2003; Sajona and Maury, 1998; Thieblemont et al.,1997). Recently, Liu et al. (2010) argued that the LCC should be rela-tively dry and reduced, whereas subducted altered oceanic crust maybe hydrous and oxidized. Our new zircon trace element analysis pro-vides strong evidence for the different fO2 between these two suitesof adakitic magmas.

Although quantitative calculation of fO2 by zircon is not availableto date, qualitative estimating fO2 based on zircon Ce4+/Ce3+ andEu/Eu* is still helpful for deciphering the fundamental difference forpetrogenetic and ore forming processes for the spatially and tempo-rally related adakites. Zircons Ce4+/Ce3+ and Eu/Eu* are effectiveredox state indictors of magma (Ballard et al., 2002) that higherCe4+/Ce3+ and Eu/Eu* correspond to higher fO2 of the magmas. Asillustrated in Fig. 7, magmatic zircons from the LYRB adakites displaysystematically higher Ce4+/Ce3+ and Eu/Eu* than those from theSTLF. Therefore, the parental magmas of the LYRB adakites shouldhave much higher fO2 than the magmas of the STLF adakites. Thisdemonstrates that the LYRB ore-bearing magmas were indeed moreoxidized than the STLF ore-barren magmas. Combined with their

contrasting sources features, we can conclude that the LYRB adakitesare genetically similar to those from subducted oceanic crust withhigh fO2 (Mungall, 2002; Sillitoe, 2010; Sun et al., 2007), whileadakitic rocks from the delaminated lower crust have low fO2,which may be due to the generally dry character of ancient LCCrocks (e.g., eclogites) (Xia et al., 2006). The large-scale Cu–Au miner-alization in the LYRB is thus closely associated with conditions ofmelting of subducted oceanic slab. In contrast, adakitic rocks derivedfrom the delaminated LCC does not form Cu–Au ore deposits.

6.4. Controlling factors of high fo2 for magmatic Cu–Au mineralization

Although arc magmas normally have high fO2, the origin of highfO2 was hotly debated. Fluids released from subducted slabs werecommonly invoked to explain the elevation of oxidation state in themantle wedge. Mungall (2002) suggests that involvement of oxidizedsediments enriched in Fe3+ during slab subduction could control theredox state of arc magmas above the FMQ buffer. Sun et al. (2004)suggests that magnetite crystallization can be the one key factor tocontrol the fO2 of evolved magmas. Positive correlation betweenredox-sensitive indices (such as Fe3+/∑Fe) and water contents inprimitive undegassed basaltic glass and melt inclusions proved aquantitative link between oxidation state and the fluid release duringsubduction process (Kelley and Cottrell, 2009). However, recently,based on Zn/Fe systematic, Lee et al. (2010) argued that the redoxstates of arc magmas are not significantly distinguishable fromthose of mid-ocean ridge basalts and high fO2 of arc magma mayresult from shallow-level differentiation processes. Clearly, theredox state of the mantle wedge and the reason for the high fO2 ofarc lavas are still unknown.

Compared with the STLF ore-barren adakitic rocks, the LYRBore-bearing adakites likely derived from oceanic slab with sedimentshave higher fO2 and δ18O. Thus oxidized marine sediments are themost likely candidate to promote the fO2 of adakites. According toMungall (2002), involvement of Fe3+-enriched oxidized sedimentscould increase oxidation of arc magma/adakitic magma, increasingCe4+/Ce3+ ratios as a result of higher proportions of sedimentsinvolved to the magma source. Zircons from the LYRB adakites shouldshow positive correlations between δ18O and Ce4+/Ce3+. Indeed, zir-con Ce4+/Ce3+ ratios and δ18O values in the LYRB adakites seem to bepositively correlated, although the correlation is broad (Fig. 7B). Thismay reflect the oxide state of sediments is variable. Generally,


sediments in subduction zone are variable in composition from ter-rigenous sediment, turbidite, hydrogenous, organic carbon enrichedsediments (Vervoort et al., 2011). These various types of involvedsediments have different water content and oxygen fugacity condi-tions, e.g. terrigenous sediment has great effect of oxidation becauseof its high Fe3+ content and organic carbon enriched sedimentsshould reduce the redox state of magma in subduction zones. Giventhat the high fO2 was generally accompanied with the elevated δ18Ovalues, high fO2 of adakites from LYRB were likely controlled by ter-rigenous sediments with few reduced sediments (e.g., sedimentswith some dead body of organisms). Moreover, the heterogeneousoxygen isotopic compositions of sediments may also affect the corre-lation between δ18O and Ce4+/Ce3+.

Ore-barren adakites from the STLF provide more constrains on theredox state of the LCC. Lower zircon Ce4+/Ce3+ ratios in the STLFadakites indicate that the LCC has low fO2. Thus, adakitic meltsderived from the LCC do not have ability to pre-concentratechalcophile elements (Cu, Au) during the adakite magma genesis.

7. Conclusions

In-situ zircon O-Hf isotopes and trace elements of the LYRBore-bearing adakites and the STLF ore-barren adakitic rocks fromcentral-eastern China show that the LYRB adakites have variablylower Hf and heavier O isotopic compositions than those from theSTLF. Our new data on Hf–O isotopes and Ti-in-zircon temperaturedata support the conclusion of Liu et al. (2010) that the STLF adakiticrocks were generated through partial melting of the delaminated dryLCC of Yangtze Block, whereas the LYRB adakites were fromwater-rich subducted oceanic crust containing sediments. The higherCe4+/Ce3+ and Eu/Eu* of the LYRB zircons than those from the STLFindicate that the subduction slab-derived melt has relatively higherfO2 than the LCC-derived melt, which could be a main reason fortheir genetic relation to the Cu–Au mineralization. The correlationbetween zirconCe4+/Ce3+ and oxygen isotopic compositions suggestthat terrigenous sediment in subduction zonemay be an important can-didate to control fO2 of adakite. These results argue that the large-scaleCu–Aumineralization related to the LYRB is due to high oxidation of thesubducted oceanic slab, and low fO2 adakitic rocks derived fromdelaminated LCC are not favorable for Cu–Au mineralization.

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.lithos.2012.10.017.

Acknowledgements

We would like to thank Doctor Anastassia Y. Borisova, ProfessorWeidong Sun and the Editor, G. Nelson Eby, for critical reviews andhelpful comments which greatly improved the manuscript. Wethank Qiuli Li, Yu Liu, and Guoqing Tang for help during Cameca zir-con oxygen isotope analysis and Kaiyun Chen, Chunlei Zong,Mengning Dai and Zhenghui Hou for zircon Th–U–Pb–Hf isotopeand trace element analysis. We thank Drs. Wei Yang and Ji Shen forhelpful discussion on an early draft of this paper. We also thank Doc-tor Anastassia Y. Borisova and Professor Fang Huang for polishing thelanguage.

This work was supported by the State Natural Sciences FoundationMonumental Projects (Nos. 41090372, 41203028, 40921002, and90814008) and Academy of Science of China (Nos. XDA08110000 andKZCX1-YW-15-3).

References

Ballard, J.R., Palin, J.M., Campbell, I.H., 2002. Relative oxidation states of magmasinferred from Ce (IV)/Ce (III) in zircon: application to porphyry copper depositsof northern Chile. Contributions to Mineralogy and Petrology 144, 347–364.

Ballhaus, C., 1993. Redox states of lithospheric and asthenospheric upper mantle.Contributions to Mineralogy and Petrology 114, 331–348.

Bernard, A., Knittel, U., Weber, B., Weis, D., Albrecht, A., Hattori, K., Klein, J., Oles, D.(Eds.), 1996. Petrology and geochemistry of the 1991 eruption products of MountPinatubo. Fire and mud. Eruptions and Lahars of Mount Pinatubo, Philippines.University of Washington Press, Seattle (767–798 pp.).

Bindeman, I.N., Eiler, J.M., Yogodzinski, G.M., Tatsumi, Y., Stern, C.R., Grove, T.L.,Portnyagin, M., Hoernle, K., Danyushevsky, L.V., 2005. Oxygen isotope evidencefor slab melting in modern and ancient subduction zones. Earth and PlanetaryScience Letters 235 (3–4), 480–496.

Black, L.P., Kamo, S.L., Allen, C.M., Davis, D.W., Aleinikoff, J.N., Valley, J.W., Mundil, R.,Campbell, I.H., Korsch, R.J., Williams, I.S., Foudoulis, C., 2004. Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-relatedmatrix effect; SHRIMP, ID-TIMS, ELA-ICP-MS and oxygen isotope documentationfor a series of zircon standards. Chemical Geology 205 (1–2), 115–140.

Blundy, J., Wood, B., 1994. Prediction of crystal-melt partition-coefficients fromelastic-moduli. Nature 372 (6505), 452–454.

Borisova, A.Y., Pichavant, M., Polve, M., Wiedenbeck, M., Freydier, R., Candaudap, F.,2006. Trace element geochemistry of the 1991Mt. Pinatubo silicic melts, Philippines:implications for ore-forming potential of adakitic magmatism. Geochimica etCosmochimica Acta 70 (14), 3702–3716.

Bouvier, A., Vervoort, J.D., Patchett, P.J., 2008. The Lu–Hf and Sm–Nd isotopic compositionof CHUR: Constraints from unequilibrated chondrites and implications for the bulkcomposition of terrestrial planets. Earth and Planetary Science Letters 273 (1–2),48–57.

Burnham, A.D., Berry, A.J., 2012. An experimental study of trace element partitioningbetween zircon and melt as a function of oxygen fugacity. Geochimica etCosmochimica Acta http://dx.doi.org/10.1016/j.gca.2012.07.034.

Chang, Y.F., Liu, X.P., Wu, Y.C., 1991. The Copper–Iron Belt of the Lower and MiddleReaches of the Changjiang River. Geological Publishing House, Beijing . (379 pp.).

Chauvel, C., Lewin, E., Carpentier, M., Arndt, N.T., Marini, J.C., 2008. Role of recycled oceanicbasalt and sediment in generating the Hf–Nd mantle array. Nature Geoscience 1 (1),64–67.

Chen, J., Jahn, B., 1998. Crustal evolution of southeastern China: Nd and Sr isotopicevidence. Tectonophysics 284 (1–2), 101–133.

Chen, J.F., Zhou, T.X., Zhang, X., Xing, F.M., Xu, X., Li, X.M., Xu, L.H., 1993. Isotopicgeochemistry of copper-bearing rocks from middle-lower area of Yangtze. TheStudy of Isotopic Geochemistry. Zhejiang University Press, Hangzhou, pp. 214–229.

Cherniak, D.J., Watson, E.B., 2003. Diffusion in zircon. Reviews in Mineralogy andGeochemistry 53 (1), 113–143.

Cong, B., Wang, Q., 1999. The Dabie-Sulu UHP rocks belt: review and prospect. ChineseScience Bulletin 44 (12), 1074–1086.

Defant, M., Drummond, M., 1990. Derivation of some modern arc magmas by meltingof young subducted lithosphere. Nature 347 (6294), 662–665.

Elhlou, S., Belousova, E., Griffin, W.L., Pearson, N.J., O'Reilly, S.Y., 2006. Trace elementand isotopic composition of GJ-red zircon standard by laser ablation. Geochimicaet Cosmochimica Acta 70 (18), A158-A158.

Gao, S., Ling, W., Qiu, Y., Lian, Z., Hartmann, G., Simon, K., 1999. Contrasting geochemicaland Sm–Nd isotopic compositions of Archean metasediments from the Konglinghigh-grade terrain of the Yangtze craton: evidence for cratonic evolution andredistribution of REE during crustal anatexis. Geochimica et Cosmochimica Acta 63(13–14), 2071–2088.

Griffin, W.L., Pearson, N.J., Belousova, E., Jackson, S.E., van Achterbergh, E., O'Reilly, S.Y.,Shee, S.R., 2000. The Hf isotope composition of cratonic mantle: LAM-MC-ICPMSanalysis of zircon megacrysts in kimberlites. Geochimica et Cosmochimica Acta64 (1), 133–147.

Grove, T.L., Elkins-Tanton, L.T., Parman, S.W., Chatterjee, N., Muntener, O., Gaetani, G.A.,2003. Fractional crystallization and mantle-melting controls on calc-alkalinedifferentiation trends. Contributions to Mineralogy and Petrology 145 (5), 515–533.

He, Y., Li, S., Hoefs, J., Huang, F., Liu, S.-A., Hou, Z., 2011. Post-collisional granitoids fromthe Dabie orogen: new evidence for partial melting of a thickened continentalcrust. Geochimica et Cosmochimica Acta 75 (13), 3815–3838.

Hoefs, J., 2009. Stable Isotope Geochemistry. Springer Verlag.Hoskin, P.W.O., Schaltegger, U., 2003. The composition of zircon and igneous

and metamorphic petrogenesis. Reviews in Mineralogy and Geochemistry 53 (1),27–62.

Huang, F., Li, S.G., Dong, F., He, Y.S., Chen, F.K., 2008. High-Mg adakitic rocks in theDabie orogen, central China: implications for foundering mechanism of lowercontinental crust. Chemical Geology 255 (1–2), 1–13.

Huang, F., Li, S., Dong, F., Li, Q., Chen, F., Wang, Y., Yang, W., 2007. Recycling of deeplysubducted continental crust in the Dabie Mountains, central China. Lithos 96 (1–2),151–169.

Imai, A., 2002. Metallogenesis of porphyry Cu deposits of the western Luzon arc,Philippines: K–Ar ages, SO3 contents of microphenocrystic apatite and significanceof intrusive rocks. Resource Geology 52 (2), 147–161.

Jackson, S.E., Pearson, N.J., Griffin, W.L., Belousova, E.A., 2004. The application of laserablation-inductively coupled plasma-mass spectrometry to in situ U–Pb zircongeochronology. Chemical Geology 211 (1–2), 47–69.

Jiang, S.Y., Li, H., Ding, X., Jiang, Y.H., Gu, L.X., Ni, P., 2008. Geochemical and Sr–Nd–Hfisotopic compositions of granodiorite from the Wushan copper deposit, JiangxiProvince and their implications for petrogenesis. Acta Petrologica Sinica 24 (8),1679–1690.

Kay, R., 1978. Aleutian magnesian andesites: melts from subducted Pacific Ocean crust.Journal of Volcanology and Geothermal Research 4 (1), 117–132.

Kelley, K.A., Cottrell, E., 2009. Water and the oxidation state of subduction zonemagmas. Science 325 (5940), 605–607.



http://dx.doi.org/10.1016/j.gca.2012.07.034


Kemp, A.I.S., Hawkesworth, C.J., Foster, G.L., Paterson, B.A., Woodhead, J.D., Hergt, J.M.,Gray, C.M., Whitehouse, M.J., 2007. Magmatic and crustal differentiation history ofgranitic rocks from Hf–O isotopes in zircon. Science 315 (5814), 980–983.

Kempton, P.D., Harmon, R.S., 1992. Oxygen isotope evidence for large-scale hybridizationof the lower crust during magmatic underplating. Geochimica et Cosmochimica Acta56 (3), 971–986.

Lee, C.-T.A., Luffi, P., Le Roux, V., Dasgupta, R., Albarede, F., Leeman, W.P., 2010. Theredox state of arc mantle using Zn/Fe systematics. Nature 468 (7324), 681–685.

Li, X., McCulloch, M.T., 1996. Secular variation in the Nd isotopic composition ofNeoproterozoic sediments from the southern margin of the Yangtze Block: evi-dence for a Proterozoic continental collision in southeast China. Precambrian Re-search 76 (1), 67–76.

Li, S., Xiao, Y., Liou, D., Chen, Y., Ge, N., Zhang, Z., Sun, S., Cong, B., Zhang, R., Hart, S.R.,1993. Collision of theNorth China and Yangtse Blocks and formation of coesite-bearingeclogites: timing and processes. Chemical Geology 109 (1–4), 89–111.

Li, S.G., Jagoutz, E., Chen, Y.Z., Li, Q.L., 2000. Sm–Nd and Rb–Sr isotopic chronology andcooling history of ultrahigh pressure metamorphic rocks and their country rocks atShuanghe in the Dabie Mountains, Central China. Geochimica et CosmochimicaActa 64 (6), 1077–1093.

Li, X.H., Li, W.X., Li, Z.X., 2005. Neoproterozoic bimodal magmatism in the Cathaysia Blockof South China and its tectonic significance. Precambrian Research 136 (1), 51–66.

Li, J.W., Zhao, X.F., Zhou, M.F., Ma, C.Q., de Souza, Z.S., Vasconcelos, P., 2009a. LateMesozoic magmatism from the Daye region, eastern China: U–Pb ages, petrogenesis,and geodynamic implications. Contributions to Mineralogy and Petrology 157 (3),383–409.

Li, X.H., Li, W.X., Li, Z.X., Lo, C.H., Wang, J., Ye, M.F., Yang, Y.H., 2009b. Amalgamationbetween the Yangtze and Cathaysia Blocks in South China: constraints fromSHRIMP U–Pb zircon ages, geochemistry and Nd–Hf isotopes of the Shuangxiwuvolcanic rocks. Precambrian Research 174 (1), 117–128.

Li, X.H., Li, W.X., Wang, X.C., Li, Q.L., Liu, Y., Tang, G.Q., 2009c. Role of mantle-derivedmagma in genesis of early Yanshanian granites in the Nanling Range, SouthChina: in situ zircon Hf–O isotopic constraints. Science in China Series D-EarthSciences 52 (9), 1262–1278.

Li, X.-H., Long, W.-G., Li, Q.-L., Liu, Y., Zheng, Y.-F., Yang, Y.-H., Chamberlain, K.R., Wan,D.-F., Guo, C.-H., Wang, X.-C., Tao, H., 2010a. Penglai zircon megacrysts: a potentialnew working reference material for microbeam determination of Hf–O isotopesand U–Pb age. Geostandards and Geoanalytical Research 34 (2), 117–134.

Li, X.-H., Wu-Xian, L., Xuan-Ce, W., Qiu-Li, L., Yu, L., Guo-Qiang, T., Yu-Ya, G., Wu, F.-Y.,2010b. SIMS U–Pb zircon geochronology of porphyry Cu–Au–(Mo) deposits in theYangtze River Metallogenic Belt, eastern China: magmatic response to earlyCretaceous lithospheric extension. Lithos 119, 427–438.

Li, C.-Y., Zhang, H., Wang, F.-Y., Liu, J.-Q., Sun, Y.-L., Hao, X.-L., Li, Y.-L., Sun, W., 2012a.The formation of the Dabaoshan porphyry molybdenum deposit induced by slabrollback. Lithos http://dx.doi.org/10.1016/j.lithos.2012.04.001.

Li, H., Ling, M.-X., Li, C.-Y., Zhang, H., Ding, X., Yang, X.-Y., Fan, W.-M., Li, Y.-L., Sun, W.-D.,2012b. A-type granite belts of two chemical subgroups in central eastern China:indication of ridge subduction. Lithos http://dx.doi.org/10.1016/j.lithos.2011.09.021.

Liang, H.Y., Campbell, I.H., Allen, C., Sun, W.D., Liu, C.Q., Yu, H.X., Xie, Y.W., Zhang, Y.Q.,2006. Zircon Ce4+/Ce3+ ratios and ages for Yulong ore-bearing porphyries ineastern Tibet. Mineralium Deposita 41 (2), 152–159.

Lin, W., Faure, M., Wang, Q., Monié, P., Panis, D., 2005. Triassic polyphase deformationin the Feidong-Zhangbaling Massif (eastern China) and its place in the collisionbetween the North China and South China blocks. Journal of Asian Earth Sciences25 (1), 121–136.

Ling, M.-X., Wang, F.-Y., Ding, X., Hu, Y.-H., Zhou, J.-B., Robert, E.Z., Yang, X.-Y., Sun, W.-D.,2009. Cretaceous ridge subduction along the Lower Yangtze River Belt, Eastern China.Economic Geology 104, 303–321.

Ling, M.X., Wang, F.Y., Ding, X., Zhou, J.B., Sun, W., 2011. Different origins of adakitesfrom the Dabie Mountains and the Lower Yangtze River Belt, eastern China:geochemical constraints. International Geology Review 53 (5–6), 727–740.

Liu, Y., Hu, Z., Gao, S., Günther, D., Xu, J., Gao, C., Chen, H., 2008. In situ analysis of majorand trace elements of anhydrous minerals by LA-ICP-MS without applying aninternal standard. Chemical Geology 257 (1–2), 34–43.

Liu, S.-A., Li, S., He, Y., Huang, F., 2010. Geochemical contrasts between early Cretaceousore-bearing and ore-barren high-Mg adakites in central-eastern China: implicationsfor petrogenesis and Cu–Au mineralization. Geochimica et Cosmochimica Acta 74(24), 7160–7178.

Liu, X., Fan, H.-R., Santosh, M., Hu, F.-F., Yang, K.-F., Li, Q.-L., Yang, Y.-H., Liu, Y., 2012.Remelting of Neoproterozoic relict volcanic arcs in the Middle Jurassic: implicationfor the formation of the Dexing porphyry copper deposit, Southeastern China. Lithoshttp://dx.doi.org/10.1016/j.lithos.2012.05.018.

Ludwig, K.R., 2003. Isoplot 3.0 — a geochronological tookit for Microsoft Excel. SpecialPublication, 4. Berkeley Geochronology Center, Berkeley (70 pp.).

Mao, J.W., Wang, Y.T., Lehmann, B., Yu, J.J., Du, A.D., Mei, Y.X., Li, Y.F., Zang, W.S., Stein, H.J.,Zhou, T.F., 2006. Molybdenite Re-Os and albite Ar-40/Ar-39 dating of Cu–Au–Mo andmagnetite porphyry systems in the Yangtze River valley andmetallogenic implications.Ore Geology Reviews 29 (3–4), 307–324.

McInnes, B.I.A., Gregoire, M., Binns, R.A., Herzig, P.M., Hannington, M.D., 2001. Hydrousmetasomatism of oceanic sub-arc mantle, Lihir, Papua New Guinea: petrology andgeochemistry of fluid-metasomatised mantle wedge xenoliths. Earth and PlanetaryScience Letters 188 (1–2), 169–183.

Muehlenbachs, K., 1986. Alteration of the oceanic crust and the 18O history of seawater.In: Valley, J.W., Taylor,H.P., O'Neil, J.R. (Eds.), Reviews inMineralogy, 16.MineralogicalSociety of America, pp. 425–444.

Mungall, J.E., 2002. Roasting the mantle: slab melting and the genesis of major Au andAu-rich Cu deposits. Geology 30 (10), 915–918.

Muñoz, M., Charrier, R., Fanning, C.M., Maksaev, V., Deckart, K., 2012. Zircon traceelement and O–Hf isotope analyses of mineralized intrusions from El TenienteOre Deposit, Chilean Andes: constraints on the source and magmatic evolution ofporphyry Cu–Mo related magmas. Journal of Petrology 53 (6), 1091–1122.

Niu, M.L., Zhu, G., Liu, G.S., Wang, D.X., Z, S.C., 2002. Tectonic setting and deep processesof Mesozoic magmatism inthe Middle-south segment of the Tan-Lu fault. ChineseJournal of Geological Society of America 37, 393–404 (in Chinese with Englishabstract).

Oyarzun, R., Marquez, A., Lillo, J., Lopez, I., Rivera, S., 2001. Giant versus smallporphyry copper deposits of Cenozoic age in northern Chile: adakitic versusnormal calc-alkaline magmatism. Mineralium Deposita 36 (8), 794–798.

Pan, Y.M., Dong, P., 1999. The Lower Changjiang (Yangzi/Yangtze River) metallogenicbelt, east central China: Intrusion- and wall rockhosted Cu–Fe–Au, Mo, Zn, Pb, Agdeposits. Ore Geology Reviews 15, 177–242.

Parkinson, I.J., Arculus, R.J., 1999. The redox state of subduction zones: insights fromarc-peridotites. Chemical Geology 160 (4), 409–423.

Paul, B., Woodhead, J.D., Hergt, J., Danyushevsky, L., Kunihiro, T., Nakamura, E.,2011. Melt inclusion Pb-isotope analysis by LA–MC-ICPMS: Assessment of ana-lytical performance and application to OIB genesis. Chemical Geology 289 (3–4),210–223.

Reich, M., Parada, M.A., Palacios, C., Dietrich, A., Schultz, F., Lehmann, B., 2003. Adakite-likesignature of Late Miocene intrusions at the Los Pelambres giant porphyry copperdeposit in the Andes of central Chile: metallogenic implications. MineraliumDeposita38 (7), 876–885.

Richards, J.P., Spell, T., Rameh, E., Razique, A., Fletcher, T., 2012. High Sr/Y magmasreflect arc maturity, high magmatic water content, and porphyry cu±Mo±Aupotential: examples from the Tethyan Arcs of Central and Eastern Iran and WesternPakistan. Economic Geology 107 (2), 295–332.

Sajona, F.G., Maury, R.C., 1998. Association of adakites with gold and copper mineralizationin the Philippines. Comptes Rendus de l'Académie des Sciences Series IIA - Earth andPlanetary Science 326 (1), 27–34.

Scherer, E., Munker, C., Mezger, K., 2001. Calibration of the lutetium-hafnium clock.Science 293 (5530), 683.

Scherer, E., Whitehouse, M.J., Munker, C., 2007. Zircon as a monitor of crustal growth.Elements 3 (1), 19–24.

Sillitoe, R.H., 1997. Characteristics and controls of the largest porphyry copper-goldand epithermal gold deposits in the circum-Pacific region. Australian Journal ofEarth Sciences 44 (3), 373–388.

Sillitoe, R.H., 2010. Porphyry Copper Systems. Economic Geology 105 (1), 3–41.Sun, S.S., McDonough, W., 1989. Chemical and isotopic systematics of oceanic basalts:

implications for mantle composition and processes. Geological Society, London,Special Publications 42 (1), 313.

Sun, W., Xie, Z., Chen, J., Zhang, X., Chai, Z., Du, A., Zhao, J., Zhang, C., Zhou, T., 2003. Os-Osdating of copper and molybdenum deposits along themiddle and lower reaches ofthe Yangtze River, China. Economic Geology 98 (1), 175–180.

Sun, W.D., Arculus, R.J., Kamenetsky, V.S., Binns, R.A., 2004. Release of gold-bearingfluids in convergent margin magmas prompted by magnetite crystallization.Nature 431 (7011), 975–978.

Sun,W., Ding, X., Hu, Y.H., Li, X.H., 2007. The golden transformation of the Cretaceous platesubduction in the west Pacific. Earth and Planetary Science Letters 262 (3–4),533–542.

Sun, W.D., Ling, M.X., Yang, X.Y., Fan, W.M., Ding, X., Liang, H.Y., 2010. Ridge subductionand porphyry copper-gold mineralization: an overview. Science in China-EarthSciences 53 (4), 475–484.

Sun, W., Zhang, H., Ling, M.-X., Ding, X., Chung, S.-L., Zhou, J., Yang, X.-Y., Fan, W., 2011.The genetic association of adakites and Cu–Au ore deposits. International GeologyReview 53 (5), 691–703.

Sun, W.D., Ling, M.X., Chung, S.L., Ding, X., Yang, X.Y., Liang, H.Y., Fan, W.M., Goldfarb,R., Yin, Q.Z., 2012. Geochemical constraints on adakites of different origins andcopper mineralization. Journal of Geology 120 (1), 105–120.

Takahashi, Y., Sakashima, T., Shimizu, H., 2003. Observation of tetravalent cerium inzircon and its reduction by radiation effect. Geophysical Research Letters 30(3), 1137.

Tang, G., Wang, Q., Wyman, D.A., Li, Z.X., Zhao, Z.H., Jia, X.H., Jiang, Z.Q., 2010. Ridgesubduction and crustal growth in the Central Asian Orogenic Belt: evidence fromLate Carboniferous adakites and high-Mg diorites in the western Junggar region,northern Xinjiang (west China). Chemical Geology 277 (3–4), 281–300.

Thieblemont, D., Stein, G., Lescuyer, J.L., 1997. Epithermal and porphyry deposits: theadakite conection. Comptes Rendus de l'Academie des Sciences Serie Ii FasciculeA-Sciences De La Terre Et Des Planetes 325 (103–109).

Trail, D., Watson, E.B., Tailby, N.D., 2011. The oxidation state of Hadean magmas andimplications for early Earth/'s atmosphere. Nature 480 (7375), 79–82.

Valley, J.W., 2003. Oxygen isotopes in zircon. Reviews in Mineralogy and Geochemistry53 (1), 343–385.

Valley, J.W., Kinny, P.D., Schulze, D.J., Spicuzza, M.J., 1998. Zircon megacrysts fromkimberlite: oxygen isotope variability amongmantlemelts. Contributions toMineralogyand Petrology 133 (1–2), 1–11.

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 ofmagmatic zircon. Contributions to Mineralogy and Petrology 150 (6), 561–580.

Vervoort, J.D., Plank, T., Prytulak, J., 2011. The Hf–Nd isotopic composition of marinesediments. Geochimica et Cosmochimica Acta 75 (20), 5903–5926.

Wang, Q., Xu, J.F., Zhao, Z.H., Bao, Z.W., Xu,W., Xiong, X.L., 2004a. Cretaceous high-potassiumintrusive rocks in the Yueshan-Hongzhen area of east China: adakites in an extensionaltectonic regime within a continent. Geochemical Journal 38 (5), 417–434.





Wang, Q., Zhao, Z.H., Bao, Z.W., Xu, J.F., Liu, W., Li, C.F., Bai, Z.H., Xiong, X.L., 2004b.Geochemistry and petrogenesis of the Tongshankou and Yinzu adakitic intrusiverocks and the associated porphyry copper-molybdenum mineralization in southeastHubei, east China. Resource Geology 54 (2), 137–152.

Wang, Q., Wyman, D.A., Xu, J.-F., Zhao, Z.-H., Jian, P., Xiong, X.-L., Bao, Z.-W., Li, C.-F., Bai,Z.-H., 2006. Petrogenesis of Cretaceous adakitic and shoshonitic igneous rocks inthe Luzong area, Anhui Province (eastern China): Implications for geodynamicsand Cu–Au mineralization. Lithos 89 (3–4), 424–446.

Wang, Q., Wyman, D.A., Xu, J.F., Jian, P., Zhao, Z.H., Li, C.F., Xu, W., Ma, J.L., He, B., 2007a.Early Cretaceous adakitic granites in the Northern Dabie Complex, central China:Implications for partial melting and delamination of thickened lower crust.Geochimica Et Cosmochimica Acta 71 (10), 2609–2636.

Wang, Q., Wyman, D.A., Xu, J.F., Zhao, Z.H., Jian, P., Zi, F., 2007b. Partial melting ofthickened or delaminated lower crust in the middle of eastern China: Implicationsfor Cu-Au mineralization. Journal of Geology 115 (2), 149–161.

Wang, S.-J., Li, S.-G., An, S.-C., Hou, Z.-H., 2012. A granulite record of multistagemetamorphism and REE behavior in the Dabie orogen: Constraints from zirconand rock-forming minerals. Lithos 136–139, 109–125.

Watson, E.B., Harrison, T.M., 2005. Zircon thermometer reveals minimum meltingconditions on earliest Earth. Science 308 (5723), 841–844.

Watson, E., Wark, D., Thomas, J., 2006. Crystallization thermometers for zircon andrutile. Contributions to Mineralogy and Petrology 151 (4), 413–433.

Wiedenbeck, M., Hanchar, J.M., Peck, W.H., Sylvester, P., Valley, J., Whitehouse, M.,Kronz, A., Morishita, Y., Nasdala, L., Fiebig, J., Franchi, I., Girard, J.P., Greenwood,R.C., Hinton, R., Kita, N., Mason, P.R.D., Norman, M., Ogasawara, M., Piccoli, R.,Rhede, D., Satoh, H., Schulz-Dobrick, B., Skar, O., Spicuzza, M.J., Terada, K., Tindle,A., Togashi, S., Vennemann, T., Xie, Q., Zheng, Y.F., 2004. Further characterisationof the 91500 zircon crystal. Geostandards and Geoanalytical Research 28 (1), 9–39.

Woodhead, J.D., Hergt, J.M., 2005. A preliminary appraisal of seven natural zircon referencematerials for in situ Hf isotope determination. Geostandards and GeoanalyticalResearch 29 (2), 183–195.

Woodhead, J., Hergt, J., Shelley, M., Eggins, S., Kemp, R., 2004. Zircon Hf-isotope analysiswith an excimer laser, depth profiling, ablation of complex geometries, andconcomitant age estimation. Chemical Geology 209 (1–2), 121–135.

Wu, F.-Y., Ji, W.-Q., Sun, D.-H., Yang, Y.-H., Li, X.-H., 2012. Zircon U-Pb geochronologyand Hf isotopic compositions of the Mesozoic granites in southern Anhui Province,China. Lithos 150 (0), 6–25.

Xia, Q.K., Yang, X.Z., Deloule, E., Sheng, Y.M., Hao, Y.T., 2006. Water in the lower crustalgranulite xenoliths fromNushan, easternChina. Journal of Geophysical Research-SolidEarth 111 (B11) http://dx.doi.org/10.1029/2006jb004296.

Xie, G.Q., Mao, F.W., Li, R.L., Bierlein, F.P., 2008a. Geochemistry and Nd–Sr isotopic studies ofLate Mesozoic granitoids in the southeastern Hubei Province, Middle–Lower YangtzeRiver belt, Eastern China: petrogenesis and tectonic setting. Lithos 104 (1–4), 216–230.

Xie, J.C., Yang, X.Y., Du, J.G., Sun,W.D., 2008b. Zircon U–Pb geochronology of theMesozoicintrusive rocks in the Tongling region: implications for copper–gold mineralization.Acta Petrologica Sinica 24 (8), 1782–1800.

Xie, G., Mao, J., Zhao, H., 2011a. Zircon U–Pb geochronological and Hf isotopicconstraints on petrogenesis of Late Mesozoic intrusions in the southeast HubeiProvince, Middle–Lower Yangtze River belt (MLYRB), East China. Lithos 125(1–2), 693–710.

Xie, G., Mao, J., Zhao, H., Wei, K., Jin, S., Pan, H., Ke, Y., 2011b. Timing of skarn depositformation of the Tonglushan ore district, southeastern Hubei Province, Middle–LowerYangtze River Valley metallogenic belt and its implications. Ore Geology Reviews 43,62–77.

Xie, J., Yang, X., Sun, W., Du, J., 2012. Early Cretaceous dioritic rocks in the Tonglingregion, eastern China: implications for the tectonic settings. Lithos http://dx.doi.org/10.1016/j.lithos.2012.05.008.

Xing, F.M., 1999. The magmatic metallogenetic belt around the Yangtze River in Anhui.Geology of Anhui 9, 272–279 (in Chinese with English abstract).

Xu, J.F., Shinjo, R., Defant, M.J., Wang, Q., Rapp, R.P., 2002. Origin of Mesozoic adakiticintrusive rocks in the Ningzhen area of east China: partial melting of delaminatedlower continental crust? Geology 30 (12), 1111–1114.

Yang, X., Zhang, Z., Chi, Y., Yu, L., Zhang, Q., 2011. A porphyritic copper (gold) ore-formingmodel for the Shaxi-Changpushan district, Lower Yangtze metallogenic belt, China:geological and geochemical constraints. International Geology Review 53 (5–6),580–611.

Yuan, H.-L., Gao, S., Dai, M.-N., Zong, C.-L., Günther, D., Fontaine, G.H., Liu, X.-M., Diwu, C.,2008. Simultaneous determinations of U–Pb age, Hf isotopes and trace elementcompositions of zircon by excimer laser-ablation quadrupole and multiple-collectorICP-MS. Chemical Geology 247 (1–2), 100–118.

Zhang, Q., Wang, Y., Qian, Q., Yang, J.H., Wang, Y.L., Zhao, T.P., Guo, G.J., 2001. Thecharacteristics and tectonic-metallogenic significances of the adakites in Yanshanperiod from Eastern China. Acta Petrologica Sinica 17 (2), 236–244.

Zhang, S.B., Zheng, Y.F., Wu, Y.B., Zhao, Z.F., Gao, S., Wu, F.Y., 2006a. Zircon U–Pb ageand Hf–O isotope evidence for Paleoproterozoic metamorphic event in SouthChina. Precambrian Research 151 (3–4), 265–288.

Zhang, S.B., Zheng, Y.F., Wu, Y.B., Zhao, Z.F., Gao, S., Wu, F.Y., 2006b. Zircon U–Pb ageand Hf isotope evidence for 3.8 Ga crustal remnant and episodic reworking of Archeancrust in South China. Earth and Planetary Science Letters 252 (1–2), 56–71.

Zhao, G., Cawood, P.A., 1999. Tectonothermal evolution of the Mayuan Assemblage inthe Cathaysia Block; implications for Neoproterozoic collision-related assemblyof the South China Craton. American Journal of Science 299 (4), 309–339.

Zheng, Y.F., Fu, B., Gong, B., Li, L., 2003. Stable isotope geochemistry of ultrahighpressure metamorphic rocks from the Dabie-Sulu orogen in China: implicationsfor geodynamics and fluid regime. Earth-Science Reviews 62 (1–2), 105–161.

Zhou, T.F., Fan, Y., Yuan, F., Lu, S.M., Shang, S.G., Cooke, D., Meffre, S., Zhao, G.C., 2008.Geochronology of the volcanic rocks in the Lu-Zong basin and its significance.Science in China Series D-Earth Sciences 51 (10), 1470–1482.

Zhu, G., Song, C.Z., Wang, D.X., Liu, G.S., Xu, J.W., 2001. Studies on Ar-40/Ar-39thermochronology of strike-slip time of the Tan-Lu fault zone and their tectonicimplications. Science in China Series D-Earth Sciences 44 (11), 1002–1009.

Zi, F., Wang, Q., Tang, G.J., Song, B., Xie, L.W., Yang, Y.H., Liang, X.R., Tu, X.L., Y, L., 2008.SHRIMP U–Pb zircon geochronology and geochemistry of the Guandian pluton inHigh-Mg adakites and implications for Cu–Au mineralization central Aanhui,China: petrogenesis and geodynamic implications. Geochimica 7177 (37), 462–480.

Zimmer, M.M., Plank, T., Hauri, E.H., Yogodzinski, G.M., Stelling, P., Larsen, J., Singer, B.,Jicha, B., Mandeville, C., Nye, C.J., 2010. The role of water in generating the calc-alkalinetrend: new volatile data for aleutian magmas and a new tholeiitic index. Journal ofPetrology 51 (12), 2411–2444.

http://dx.doi.org/10.1029/2006jb004296


contrasting zircon hf–o isotopes and trace elements...

Documents