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Precambrian Research 216– 219 (2012) 177– 207

Contents lists available at SciVerse ScienceDirect

Precambrian Research

journa l h omepa g e: www.elsev ier .com/ locate /precamres

aleoproterozoic S- and A-type granites in southwestern Zhejiang: Magmatism,etamorphism and implications for the crustal evolution of the Cathaysia

asement

an Xia, Xi-Sheng Xu ∗, Kong-Yang Zhutate Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China

r t i c l e i n f o

rticle history:eceived 15 March 2012eceived in revised form 2 July 2012ccepted 6 July 2012vailable online xxx

eywords:aleoproterozoic granitesrustal growth and reworkingircon U–Pb–Hf isotopesd isotopesathaysia basement

a b s t r a c t

Paleoproterozoic granites and metamorphic rocks of the Badu complex, the oldest rocks found inCathaysia Block, provide a window for investigating the crustal evolution of the Cathaysia basement.SHRIMP and LA-ICP-MS zircon U–Pb ages of five representative granite samples from Jinluohou (Lizhuang)and Jingju granitic complexes indicate that the magmatism took place during Paleoproterozoic, and over-printed by early Mesozoic thermal event. The Jinluohou garnet-bearing biotite granite (1878 ± 28 Ma) hashigh A/CNK (1.28–1.42), low contents of P2O5 and low FeOT/(FeOT + MgO). It contains a large amount ofbiotites and garnets with minor inherited zircons but no primary muscovites, showing the S-type gran-ite affinity. It was formed at low water fugacity and high Zr saturation temperature (792–809 ◦C). TheJingju medium-coarse grained K-feldspar granite (1861 ± 35 Ma), Jingju medium-fine grained K-feldspargranite (1849 ± 30 Ma) and Jinluohou gneissic granodiorite (1877 ± 10 Ma) can reach strongly peralu-minous (A/CNK = 0.97–1.26), are enriched in alkalis and HFSE (Zr, Nb, Ce, Y) and have high Ga/Al andFeOT/(FeOT + MgO) ratios. Their high Zr saturation temperatures (840–854 ◦C, most of them are higherthan 830 ◦C) together with high Rb/Nb and Y/Nb ratios suggest that they belong to the A2 subgroupof A-type granites. The ages of inherited zircon cores from Jinluohou garnet-bearing biotite granite(2088–2929 Ma) reveal the existence of the Archean basement, and the Hf and Nd isotopes and chem-ical compositions suggest that these S- and A-type granites were originated from the Paleoproterozoic

and Archean crustal sources with different proportions of input from juvenile crust materials. The Pale-oproterozoic S- and A-type granites intruded simultaneously, and formed under intraplate extensionalgeodynamic setting, which is an important event of episodic crustal growth and reworking. The age ofJingju porphyritic quartz monzonite (226.2 ± 1.4 Ma) and the lower intercept age of Jinluohou gneissicgranodiorite, Jingju K-feldspar granite (224–231 Ma) may indicate another important thermal overprint-ing event in this region.

. Introduction

Many Nd and Hf isotopic data and U–Pb zircon ages suggesthat the accretion of continental crust is episodic with severaleaks at 2.7, 1.9, 1.8 and 1.7 Ga and a major period of accretion ata. 1.9 Ga (Condie, 1986, 1989, 1990, 2000; Taylor and McLennan,995; Kemp et al., 2006; Condie et al., 2011). Irrespective of whenhe continents attained their present mass, abundant studies onhe present age distribution of the crust using Sm–Nd isotope sys-

em suggests that 35–60% of the present crustal mass formed inhe Archean (Patchett and Arndt, 1986; McCulloch, 1987; Jacobsen,998; DePaolo et al., 1991), a considerably larger amount than

∗ Corresponding author. Tel.: +86 25 83592185; fax: +86 25 83686016.E-mail addresses: xia bruce@126.com (Y. Xia), xsxu@nju.edu.cn (X.-S. Xu).

301-9268/$ – see front matter © 2012 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.precamres.2012.07.001

© 2012 Elsevier B.V. All rights reserved.

the present area proportion of the Archean crust (14%; Goodwin,1991). The reduced proportion of the Archean crust may havereturned to the mantle, owing to crustal recycling by means ofsediment subduction, tectonic erosion at convergent margins and,perhaps, lower-crustal delamination (Armstrong, 1991; von Hueneand Scholl, 1991).

The South China is tectonically divided into two major blocks:the Yangtze Block to the northwest and the Cathaysia Block to thesoutheast (Fig. 1). The rocks of the ca. 2.9 Ga Kongling complex (Gaoet al., 1999; Qiu et al., 2000; Zheng et al., 2006; Zhang et al., 2006)are considered to be the oldest in the Yangtze Block. Although thereare no reports of Archean rocks in the Cathaysia Block, abundant

inherited zircons (Xu et al., 2007; Yu et al., 2009; Liu et al., 2009)with Archean U–Pb ages and Hf isotopic model ages, together withwhole-rock Nd model ages (Chen and Jahn, 1998; Shen et al., 2000),suggest that Mesoarchean to Neoarchean materials might exist.

178 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

Paleoproterozoicbasement

Meso- to Neoproterozoi cbasement

Phanerozoic sequence s

Fault

Granitoids

30

29

28

27

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30

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110 114 118

26

22

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Ya n g tze

C a th a ys ia

Ta iw a n

Jinhua

Xikou

Suichang

Songyang

Longquan

Badu

Jianming

Jianyang

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Fig. 2

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(tBespteaS(BdaaieUhiet

ig. 1. Simplified geological map of Cathaysia Block, SE China, illustrating the distriomplex (“Badu Group”).

ources: Modified after Hu et al. (1991), Gan et al. (1993), Li et al. (2000), Li et al. (20

oreover, characterized by episodic magmatism with several peakges including that of ca. 1.9 Ga (Ding et al., 2005; Yu et al., 2006; Xut al., 2007; Wang et al., 2010), corresponding to accretion peak agesf global continental crust mentioned above, Cathaysia Block is aood place for studying continental crust accretion and reworking.

Paleoproterozoic Badu complex and related granitic intrusionsFig. 1), the earliest petrous records in southwestern Zhejiang, con-ain information about the formation and evolution of the Cathaysialock. Paleoproterozoic granitic intrusions are extensive in South-ast Zhejiang and always exhibit gneissic structure with the sametructural orientation as the Badu complex. Most of these Paleo-roterozoic granites were regarded as S-type granites, but some ofhem might be A-type granites (Hu et al., 1991; Yu et al., 2009; Liut al., 2009). Previous studies have obtained abundant zircon U–Pbges for these gneissic granitoids (e.g. Danzhu, Lizhuang, Tianhou,anzhishu and Xiaji granites, etc.; Fig. 1), varying from 1.8 to 2.0 GaHu et al., 1991; Gan et al., 1993, 1995; Wang et al., 1998; Zhejiangureau of Geology and Mineral Resources, 1996). However, theseating results may overestimate the real rock age, because almostll dating results are discordant (only upper intercept ages beingccepted) and the mixing of inherited zircons cannot be excludedn the conventional single- or multi-grain TIMS method or zircon-vaporation analyses (Li, 1997). Recently, a batch of credible zircon–Pb ages using high-precision SHRIMP and LA-ICP-MS techniques

ave restricted the emplacement age of these gneissic granitoids

n a range of 1.83–1.89 Ga (Li and Li, 2007; Wang et al., 2008; Liut al., 2009; Yu et al., 2009). Corresponding to the granitic magma-ism, Xiang et al. (2008) obtained the age of amphibolites of 1.85 Ga

of Precambrian basement and Paleoproterozoic granitoids intruding into the Badu

an et al. (2007), Zeng et al. (2008), Liu et al. (2009) and Yu et al. (2009).

which was once viewed as formed at 1.77 Ga (Li, 1997), imply-ing that the mantle-derived magmatism and crustal magmatismoccurred simultaneously.

Although some progress has been achieved regarding the Pre-cambrian geology in this region, the age of the Cathaysia basementis still controversial, the genetic types of the Paleoproterozoic gran-ites require further constrained, and the coexisting of S- and A-typegranites and their tectonic setting remains to be clarified. We thusconduct a detailed geochronological and petrological study of thesegranitic intrusions in order to better understand the formation,growth and evolution of the Cathaysia Block.

2. Geologic background and samples

The Badu complex, formerly called “Badu Group”, includesTangyuan, Qiantou, Zhangyan, Siyuan and Dayanshan Formationsand consists mainly of mica schists, gneisses and migmatites, andbelongs to upper amphibolite facies in terms of metamorphic grade(Hu et al., 1991; Yu et al., in press). Dating of two metamorphic rocksamples from Badu complex suggests that the complex formed atca. 1.9 Ga and the protoliths of Badu complex probably depositedat some time between 2.5 Ga and 1.9 Ga (Yu et al., in press).

The Jinluohou (Lizhuang) and Jingju granitic complexes arelocated at the east of Songyang county in southwestern Zhejiang

Province, with an outcrop area of ∼12 km2 and ∼18 km2, respec-tively. Both complexes intrude into the Paleoproterozoic Baducomplex. Due to the Quaternary sedimentary cover, their rela-tionship with nearby metamorphic rocks of Badu complex is not

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Y. Xia et al. / Precambrian Rese

lear. Previous studies on Jinluohou granitic complex were con-entrated on a limited small area around Lizhuang. The Jingjuranitic complex is composed of multi-stage intrusions, includingarly stage K-feldspar granite and later stage porphyritic quartzonzonite. The Jingju K-feldspar granite can be further divided

nto medium-coarse grained K-feldspar granite and medium-finerained K-feldspar granite according to their grain size. Because ofater metamorphic overprinting, Jinluohou gneissic granodiorite,arnet-bearing biotite granite and Jingju K-feldspar granite havell developed gneissic structure with varying degrees of parallellignment constituted by mafic minerals.

Samples were collected from Jinluohou and Jingjuranitic complexes for this study (Fig. 2). Sampling loca-ions (latitude and longitude) and mineral assemblagesf the samples are listed in Table 1. Except for the lateormed porphyritic quartz monzonite with a mineral assem-lage of plagioclase + K-feldspar + quartz + biotite + amphibole,he most common mineral assemblages of Jinluohound Jingju granitic complexes are quartz + K-eldspar + plagioclase + biotite ± muscovite ± amphibole ± garnetFig. 3). Perthites can be occasionally observed in Jingju K-feldsparranite and Jinluohou gneissic granodiorite. Most of them areicroperthites and cryptoperthites with the intergrowths oficroscopic but distinct crystals of the albite and orthoclase end-embers (Fig. 3b, d and i). It is worth noting that all muscovites

n Jingju K-feldspar granite and Jinluohou garnet-bearing biotiteranite are anhedral, and sometimes occur as sericite networkeins in garnets, demonstrating they may be metamorphogeneticecondary muscovites. Representative samples were analyzedor zircon U–Pb dating, Hf-isotope compositions and whole-rock

ajor and trace element and Nd-isotope compositions. Zircon–Pb dating are calibrated at different laboratories by both SHRIMPnd LA-ICP-MS methods.

. Analytical technique

.1. Major element compositions of minerals

A JEOL JXA-8100 Electron-microprobe (EMP) at the State Keyaboratory for Mineral Deposits Research, Nanjing University issed for quantitative composition analyses of the biotites in Jingju-feldspar granite and Jinluohou gneissic granodiorite. The operat-

ng conditions included an accelerating voltage of 15 kV and a probeurrent of 2 × 10−8 A for most elements. The counting times at theeaks were 20 s for major elements. The diameter of the electroneam was 1 �m. All data were corrected with standard ZAF correc-ion procedures. Natural minerals and synthetic glasses were useds standards.

.2. U–Pb dating and trace elements of zircons

Zircons were extracted using standard density and magneticeparation techniques. Selected zircon grains were hand-pickednder a binocular microscope and abraded grains were mounted

n epoxy resin with zircon U–Pb standards BR266 and Temora 2.ounts were polished to expose zircon surfaces suitable for U–Pb

ating using either SHRIMP or LA-ICP-MS methods. Zircon cathodo-uminescence (CL) images of all five samples were taken usinghillip XL30 SEM at the Department of Physics, Curtin University,ustralia.

Zircon U–Pb dating of five samples (JJ03, JJ05, JJ07 and

arts of JLH03, JLH10) was conducted using SHRIMP at the

ohn de Laeter Centre of Mass Spectrometry, Curtin University,erth, Australia. Analytical conditions were: 10 kV, 2–5 nA O2-rimary beam, approximately 30 �m diameter spot, 10 kV positive

16– 219 (2012) 177– 207 179

secondary ions, mass resolution 5000 R (1% peak height), dataacquisition by peak switching, single electron multiplier. Pb isotopecompositions were measured directly and corrected for commonPb using the 204Pb method (e.g. Stern, 1997). Elemental abun-dances and instrumental fractionation of Pb relative to U andTh and were calibrated using zircon standard BR266 (559.1 Ma,206Pb/238U = 0.09059; Stern, 2001). Data reductions and age cal-culations were performed in SQUID 1.13B (Ludwig, 2005). ZirconU–Pb dating of the rest of JLH03 and JLH10 and trace elements of fivesamples were analyzed using an Agilent 7500a ICP-MS equippedwith a New Wave 213 nm laser sampler in the State Key Laboratoryof Mineral Deposits Research, Nanjing University. Detailed analyt-ical procedures are given in Xu et al. (2009) and Tang et al. (2012).Common Pb contents were evaluated following Andersen (2002).

3.3. Hf-isotope analysis of zircon

In situ Hf isotopic analysis of zircons were conducted using a Nuplasma MC-ICPMS, equipped with a 213 nm laser sampler at theInstitute of Geochemistry, Chinese Academy of Sciences in Guiyang,China. The analysis was done with ablation pit of 40 �m (JJ07 with60 �m) in diameter, repetition rate of 10 Hz, ablation time of 60 s,and laser beam energy of 0.099 mJ/pulse (JJ07 of 0.155 mJ/pulse).In order to evaluate the reliability of the data, zircon standard91500 was analyzed during the course of this study and yieldeda weighted mean 176Hf/177Hf ratio of 0.282309 ± 37 (2�). The ana-lytical details and interference correction method of 176Yb on 176Hfare given in Tang et al. (2008). The measured 176Lu/177Hf ratiosand the 176Lu decay constant of 1.865 × 10−11 yr−1 (Scherer et al.,2001) were used to calculate initial 176Hf/177Hf ratios. The chon-dritic values of 176Lu/177Hf = 0.0332 and 176Hf/177Hf = 0.282772(Blichert-Toft and Albarède, 1997) were used for calculating εHfvalues. The depleted mantle Hf model ages (TDM) were calculatedusing the measured 176Lu/177Hf ratios based on the assumptionthat the depleted mantle reservoir has a linear isotopic growthfrom 176Hf/177Hf = 0.279718 at 4.55 Ga to 0.283250 at present,with 176Lu/177Hf = 0.0384 (Griffin et al., 2000). The new continen-tal crust Hf model ages (TNC) were calculated using the measured176Lu/177Hf ratios based on the assumption that the new conti-nental crust reservoir (island arcs) has a linear isotopic growthfrom 176Hf/177Hf = 0.279703 at 4.55 Ga to 0.283145 at present, with176Lu/177Hf = 0.0375 (Dhuime et al., 2011). The TNC provides a betterconstraint than TDM on when the continental crust was generated(Dhuime et al., 2011). We also present a two-stage model age (T2DMor T2NC) for each zircon, which assumes that its parental magma wasproduced from an average continental crust (176Lu/177Hf = 0.015;Griffin et al., 2002) that was originally derived from the depletedmantle or island arcs.

3.4. Major and trace element analyses of whole-rocks

Whole-rock major elements analyses were done using anARL9800XP+ X-ray fluorescence (XRF) spectrometer at the Cen-ter of Modern Analysis, NJU. The analytical precision is generallybetter than 2% for all the elements. Whole-rock trace elements anal-yses were carried out at China University of Geosciences (Wuhan).For trace element analyses, ca. 50 mg were dissolved in distilledHF + HNO3 (3:1) in Savillex Teflon screw-cap capsules at 100 ◦C for2 days, dried and then digested with 6 M HCl at 150 ◦C. Three dupli-cates of three standards (AGV-1, GSR-3 and DNC-1) were prepared

using the same procedure, to monitor the analytical precision. Thesolutions were measured for trace elements using a POEMS-III ICPmass spectrometer (MS). The discrepancy among triplicates is lessthan 10% for all elements. Analyses of standards are in agreement

180 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

anitic

wd

3

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TL

M

Fig. 2. Geological map of Jinluohou and Jingju gr

ith the recommended values. The more detail analytical proce-ures were referred to Lin et al. (2000).

.5. Sr–Nd isotope analysis of whole-rocks

The Sr and Nd isotopic compositions were measured using ainnigan MAT262 thermal ionization mass spectrometer (TIMS)t the Institute of Geology and Geophysics, Chinese Academyf Sciences following the procedure of Zhang et al. (2002).ong-term laboratory measurements of the JNdi-1 Nd and

BS 987 Sr standards yield 143Nd/144Nd = 0.512105 ± 12 (2�)nd 87Sr/86Sr = 0.710272 ± 10 (2�), respectively. The isotopicatios were corrected for mass fractionation by normalizing to46Nd/144Nd = 0.7219 and 86Sr/88Sr = 0.1194, respectively.

able 1ithologies and mineral assemblages of Jinluohou and Jingju granitic complexes.

Granitic complexes Lithology M

Jingju

Medium-coarse grained K-feldspar granite KfMedium-fine grained K-feldspar granite KfPorphyritic quartzmonzonite

Pl

Jinluohou

Gneissic granodiorite Pl

Garnet-bearing biotitegranite

Qz

ineral abbreviation: Qtz, quartz; Kfs, K-feldspar; Pl, plagioclase; Bt, biotite; Ms, muscovi

complexes. Sample locations are also indicated.

4. Analytical results

4.1. Biotite compositions

The compositions of biotites in Jingju K-feldspar granite andJinluohou gneissic granodiorite are shown in Table 2. Because ofchloritization, the total major element contents are low withoutanalyzing H2O. In spite of this alteration, the FeOT/(FeOT + MgO)ratios should remain largely unchanged (see discussion below).

All the chloritic biotites in Jingju K-feldspar granite and Jinluo-hou gneissic granodiorite are close to the Fe-rich siderophyllite-annite end member with high FeOT/(FeOT + MgO) ratios ranging

from 0.702 to 0.802 (Fig. 4).

Using the geothermometer given by Luhr et al. (1984):T (K) = 838/(1.0337 − Ti/Fe2+), the crystallization temperature ofJingju K-feldspar granite and Jinluohou gneissic granodiorite are

ain minerals Sample no. Location (GPS position)

s + Qz + Pl + Bt + Ms JJ03 N28◦22′16.9′′ E119◦35′40′′

s + Qz + Pl + Bt + Ms JJ05 N28◦22′34.9′′ E119◦36′13.5′′

+ Kfs + Qz + Bt + AmpJJ06 N28◦24′2.5′′ E119◦37′3.9′′

JJ07 N28◦25′31.7′′ E119◦37′11.1′′

+ Qz + Kfs + Bt + AmpJLH03 N28◦28′28.6′′ E119◦32′38.7′′

JLH04 N28◦28′18.5′′ E119◦33′0.9′′

JLH06 N28◦27′59.2′′ E119◦33′22.5′′

+ Kfs + Pl + Bt + Grt + MsJLH08 N28◦27′3.6′′ E119◦34′12.8′′

JLH09 N28◦27′42.8′′ E119◦34′38.9′′

JLH10 N28◦28′4.7′′ E119◦34′58.7′′

te; Amp, amphibole; Grt, Garnet.

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216– 219 (2012) 177– 207181

Table 2Representative microprobe analyses of biotites in the Jingju K-feldspar granite and Jinluohou gneissic granodiorite.

Sample JLH03 JJ03 JJ05

No. 2b 4 6 27 30 2 3 4 5 6 7b 8 1 3 5 6 7b 8

SiO2 31.72 25.28 26.08 21.99 23.22 29.93 28.14 25.07 27.40 26.82 37.88 26.64 24.71 23.23 24.07 22.92 34.37 23.54TiO2 0.38 0.11 0.13 0.07 0.22 0.03 0.72 0.02 0.01 0.05 0.39 0.08 1.17 0.13 0.17 0.14 0.51 0.14Al2O3 19.95 18.71 17.82 18.09 17.69 19.36 18.92 18.88 19.60 19.47 24.15 20.65 19.21 21.02 19.77 20.28 22.90 19.96FeOT 28.60 36.98 36.77 37.50 36.98 28.05 29.57 32.24 30.44 31.93 21.75 33.29 32.62 34.27 33.57 33.52 23.28 35.28MnO 0.16 1.43 1.35 1.45 1.31 0.19 0.20 0.27 0.22 0.20 0.14 0.24 0.25 0.28 0.30 0.27 0.15 0.27MgO 5.79 5.12 5.77 5.24 5.55 5.08 5.38 6.19 6.39 6.10 3.36 4.77 6.42 7.29 7.30 7.17 5.55 6.91CaO 0.43 0.03 0.04 0.11 0.09 0.60 0.47 0.49 0.52 0.54 0.35 0.47 0.16 0.04 0.09 0.01 0.08 0.06Na2O 0.12 0.14 0.09 0.07 0.10 0.15 0.13 0.01 0.08 0.07 0.09 0.10 0.37 0.10 0.04 0.09 0.17 0.04K2O 1.34 0.05 0.13 0.02 0.04 2.42 1.63 0.32 0.63 0.36 3.49 0.48 0.90 0.03 0.28 0.07 2.71 0.01F 0.11 0.07 0.06 0.05 0.06 0.14 0.19 0.12 0.11 0.15 0.19 0.09 0.20 0.14 0.16 0.13 0.27 0.18Li2Oa 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.32 0.00 0.00 0.00 0.00 0.00 0.31 0.00H2Oa 3.58 3.34 3.37 3.16 3.20 3.42 3.33 3.23 3.37 3.34 3.93 3.39 3.27 3.31 3.27 3.24 3.70 3.26Total 92.18 91.26 91.60 87.74 88.46 89.36 88.67 86.83 88.76 89.01 97.02 90.20 89.28 89.81 89.01 87.83 93.99 89.65O = F, Cl 0.05 0.03 0.03 0.02 0.02 0.06 0.08 0.05 0.05 0.06 0.08 0.04 0.08 0.06 0.07 0.05 0.11 0.07Total 92.13 91.23 91.57 87.72 88.44 89.31 88.59 86.78 88.71 88.95 96.94 90.16 89.20 89.76 88.94 87.78 93.88 89.57

Cations based on 22 oxygen anionsSi 5.231 4.493 4.606 4.146 4.308 5.158 4.937 4.569 4.797 4.721 5.643 4.652 4.409 4.131 4.310 4.167 5.384 4.221AlIV 2.769 3.507 3.394 3.854 3.692 2.842 3.063 3.431 3.203 3.279 2.357 3.348 3.591 3.869 3.690 3.833 2.616 3.779AlVI 1.109 0.413 0.316 0.168 0.178 1.091 0.849 0.625 0.842 0.761 1.883 0.903 0.448 0.536 0.482 0.514 1.611 0.437Ti 0.047 0.015 0.017 0.010 0.030 0.004 0.095 0.003 0.001 0.006 0.043 0.010 0.157 0.017 0.023 0.019 0.060 0.019Fe 3.945 5.498 5.431 5.914 5.737 4.042 4.339 4.915 4.456 4.701 2.709 4.863 4.867 5.096 5.027 5.097 3.049 5.289Mn 0.022 0.215 0.202 0.231 0.206 0.027 0.030 0.042 0.032 0.030 0.018 0.036 0.038 0.041 0.045 0.042 0.019 0.041Mg 1.424 1.356 1.518 1.474 1.536 1.304 1.406 1.683 1.666 1.601 0.746 1.242 1.708 1.933 1.949 1.942 1.295 1.847Lia 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.790 0.000 0.000 0.000 0.000 0.000 0.197 0.000Ca 0.077 0.006 0.008 0.022 0.017 0.111 0.088 0.095 0.098 0.101 0.055 0.088 0.030 0.007 0.017 0.003 0.014 0.011Na 0.039 0.048 0.029 0.024 0.037 0.051 0.045 0.003 0.026 0.022 0.025 0.034 0.127 0.034 0.012 0.031 0.051 0.012K 0.283 0.012 0.030 0.005 0.010 0.532 0.364 0.073 0.140 0.081 0.664 0.107 0.206 0.006 0.063 0.016 0.541 0.003OHa 3.943 3.962 3.965 3.973 3.965 3.926 3.897 3.931 3.938 3.917 3.910 3.950 3.890 3.923 3.909 3.926 3.868 3.900F 0.057 0.038 0.035 0.027 0.035 0.074 0.103 0.069 0.062 0.083 0.090 0.050 0.110 0.077 0.091 0.074 0.132 0.100Y total 6.546 7.496 7.484 7.796 7.687 6.469 6.719 7.267 6.998 7.100 6.189 7.054 7.218 7.623 7.526 7.614 6.232 7.633X total 0.398 0.067 0.068 0.051 0.064 0.695 0.497 0.171 0.265 0.204 0.744 0.229 0.363 0.047 0.093 0.049 0.606 0.027Al total 3.878 3.920 3.710 4.022 3.869 3.933 3.912 4.055 4.044 4.040 4.240 4.250 4.039 4.405 4.172 4.347 4.228 4.217FeT/(FeT + Mg) 0.735 0.802 0.782 0.801 0.789 0.756 0.755 0.745 0.728 0.746 0.784 0.797 0.740 0.725 0.721 0.724 0.702 0.741T (◦C) 820 813 813 812 815 811 828 811 811 812 823 812 837 813 814 814 826 813

T is calculated by geothermometer based on the coupled exchange of Ti and Fe in biotites after Luhr et al. (1984).a Li2O and H2O calculations after Tindle and Webb (1990).b The most weakly altered mineral grain.

182 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

Fig. 3. Photomicrographs of representative samples from Jingluohou and Jingju granitic complexes (crossed nicols). (a) and (b) Jingju medium-coarse grained K-feldsparg porpg , plagis

cmbbl

4

sFgT

ranite; (c) and (d) Jingju medium-fine grained K-feldspar granite; (e) and (f) Jingjuarnet-bearing biotite granite. Mineral abbreviation: Qtz, quartz; Kfs, K-feldspar; Plericite; Zrn, zircon.

alculated. Considering the effect of choritization (e.g. the compli-entary sphene or rutile may decrease the Ti content of the host

iotite), the calculated temperatures of 811–837 ◦C in Table 2 maye regarded as the low temperature limit. Therefore they crystal-

ized at temperature higher than 811 ◦C.

.2. Zircons U–Pb geochronology and trace elements

The locations of selected samples for zircon U–Pb dating are

hown in Fig. 2. CL images of representative zircons are shown inig. 5. The trace element and age results for samples of these tworanitic complexes are graphically shown in Figs. 6 and 7 (also seeables 3 and 4). Because of counting statistics, 207Pb/206Pb ages

hyritic quartz monzonite; (g)–(i) Jinluohou gneissic granodiorite; (j)–(l) Jinluohouoclase; Per, perthite; Bt, biotite; Ms, muscovite; Amp, amphibole; Grt, Garnet; Ser,

are more precise for older zircons, while 206Pb/238U ages are moreprecise for younger zircons (Griffin et al., 2004). Therefore, we usethe 207Pb/206Pb ages for older (>1 Ga) zircons, and 206Pb/238U agesfor younger zircons, in the following discussion. The trace elementsare analyzed at the domain near the analysis spots on zircons whichthe U–Pb dating have been previously done by either SHRIMP orLA-ICP-MS (Fig. 5).

4.2.1. Jingju K-feldspar granite (JJ03 and JJ05)

Sample JJ03 and JJ05 have been selected from the Jingju

medium-coarse grained K-feldspar granite and medium-finegrained K-feldspar granite, respectively, for analyses. Zircons sepa-rated from JJ03 are stubby prismatic or ellipsoidal in shape with

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Table 3Trace elements of zircons from samples of Jinluohou and Jingju granitic complexes.

Sample No.a Age (Ma)a Age (Ma)b La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Eu/Eu* Ce/Ce*

Jingju medium-fine grained K-feldspar graniteJJ03-01 SH-2 1883 ± 47 1885 ± 53 0.06 4.82 0.36 4.63 8.83 0.76 47.23 15.17 183.05 66.88 281.15 54.32 459.04 83.67 0.09 3.66JJ03-02 SH-40 217 ± 4 219 ± 9 3.29 12.89 2.50 19.71 16.41 0.86 45.99 12.73 124.58 38.17 148.94 28.37 239.07 41.95 0.09 0.99JJ03-03 SH-39 218 ± 3 219 ± 10 94.30 122.83 24.04 96.79 38.56 0.87 50.17 13.20 116.70 35.82 130.48 23.96 204.46 35.76 0.06 0.59JJ03-04 SH-10 228 ± 2 228 ± 5 0.05 2.33 0.06 0.61 0.92 0.10 5.38 1.39 15.17 4.67 17.99 3.29 29.42 5.55 0.10 8.58JJ03-06 SH-12 1859 ± 3 1855 ± 69 0.13 1.54 0.13 1.19 3.60 0.14 31.19 13.12 156.84 43.40 138.04 21.45 164.99 26.11 0.03 2.55JJ03-09 SH-32 225 ± 2 226 ± 9 1.14 2.89 0.36 3.96 4.41 0.26 19.01 6.61 78.86 24.49 99.65 18.90 164.04 30.78 0.07 1.06JJ03-10 SH-19 1938 ± 127 1893 ± 73 0.06 1.50 0.08 1.08 3.28 0.11 22.79 8.55 117.15 44.43 201.76 42.21 367.91 69.19 0.03 4.15JJ03-11 SH-37 223 ± 2 231 ± 5 60.85 132.28 16.41 61.16 14.56 0.17 35.87 9.31 98.69 30.77 126.03 24.78 210.56 39.95 0.02 0.97JJ03-12 SH-36 234 ± 2 235 ± 6 10.26 22.68 5.72 37.62 22.10 0.82 43.63 15.23 170.39 52.37 236.70 50.14 438.29 79.57 0.08 0.68

Jingju medium-coarse grained K-feldspar graniteJJ05-01 SH-2 1877 ± 49 1877 ± 65 0.08 1.54 0.07 1.09 3.33 0.08 19.55 7.46 100.38 38.16 171.23 36.73 317.63 61.37 0.02 4.29JJ05-02 SH-6 231 ± 4 231 ± 8 9.52 26.49 3.67 20.10 11.83 0.39 35.44 9.69 100.71 30.82 125.02 23.51 200.95 36.72 0.05 1.05JJ05-03 SH-8 1762 ± 216 1763 ± 47 0.06 1.45 0.07 0.91 2.66 0.09 17.01 6.57 88.32 35.09 164.75 33.78 317.28 60.77 0.03 4.50JJ05-04 SH-14.1 1845 ± 10 1845 ± 49 0.08 1.90 0.06 0.90 3.34 0.08 22.15 7.96 108.42 41.75 187.02 37.45 334.11 63.61 0.02 6.17JJ05-06 SH-13 227 ± 4 227 ± 8 14.85 42.11 6.02 26.21 9.64 0.08 26.32 7.66 90.00 26.30 103.54 19.01 154.80 26.33 0.01 4.04JJ05-07 SH-10 1815 ± 35 1856 ± 72 0.17 2.45 0.12 1.61 2.90 0.11 22.85 7.45 102.68 38.07 177.67 36.18 334.18 65.47 0.03 3.82JJ05-08 SH-17 227 ± 2 227 ± 5 1.41 3.99 0.91 5.37 10.04 0.43 42.53 11.37 119.55 33.20 130.71 24.26 201.49 34.97 0.05 0.80JJ05-11 SH-15 225 ± 4 227 ± 15 0.20 34.15 0.38 8.23 11.71 0.87 45.85 13.31 134.37 43.55 165.78 32.15 278.11 51.31 0.04 10.10

Jingju porphyritic quartz monzoniteJJ07-01 SH-2 224 ± 2 225 ± 5 0.09 11.41 0.07 1.22 2.33 0.31 16.74 6.24 87.61 35.81 176.56 39.12 382.07 75.09 0.11 30.22JJ07-02 SH-3 223 ± 3 221 ± 3 0.21 14.52 0.12 1.32 3.06 0.36 15.34 5.16 66.88 25.83 120.96 26.60 248.77 49.46 0.13 21.41JJ07-03 SH-14 226 ± 1 227 ± 6 0.29 19.93 0.13 1.33 2.40 0.61 16.75 5.80 75.64 27.40 127.69 27.44 260.09 51.43 0.21 24.52JJ07-04 SH-15 226 ± 4 227 ± 4 0.10 14.05 0.07 0.89 2.44 0.29 13.43 4.91 62.58 24.24 122.30 26.63 258.64 52.49 0.12 37.05JJ07-06 SH-11 228 ± 2 228 ± 4 0.21 21.81 0.13 1.48 4.51 0.60 19.13 6.87 84.81 32.60 150.59 33.47 400.12 64.53 0.17 30.51

Jinluohou gneissic granodioriteJLH03-01 SH-9 224 ± 5 225 ± 315 0.17 0.68 0.23 1.12 1.61 0.39 3.31 0.87 9.20 3.33 11.23 1.69 13.78 3.09 0.50 0.66JLH03-02 SH-9C 1840 ± 21 1841 ± 83 0.13 4.60 0.16 2.25 3.25 0.22 17.33 5.61 70.89 26.50 115.89 22.68 202.53 37.82 0.07 6.40JLH03-03 SH-21 1877 ± 14 1877 ± 116 0.05 1.41 0.13 1.41 3.43 0.13 28.70 11.26 157.86 59.36 274.84 56.67 499.79 96.72 0.03 2.77JLH03-04 SH-20 249 ± 5 251 ± 16 14.23 50.98 0.52 4.62 2.43 0.80 2.52 0.55 3.81 2.39 10.67 2.60 47.41 6.23 0.98 2.50JLH03-06 LA-19 1807 ± 53 1808 ± 78 0.06 1.67 0.07 0.98 2.51 0.10 19.96 7.01 92.13 34.77 157.08 31.70 278.44 52.46 0.03 5.20JLH03-08 LA-17 1841 ± 27 1841 ± 59 0.04 3.82 0.11 2.32 5.73 0.22 33.25 11.07 138.11 51.23 221.06 43.69 375.90 69.92 0.04 8.54JLH03-10 LA-10 1875 ± 44 1875 ± 43 0.06 1.60 0.06 1.07 3.72 0.12 23.77 8.37 108.93 39.50 176.76 35.15 300.72 55.89 0.03 5.36JLH03-13 SH-15 236 ± 4 225 ± 30 0.05 0.48 0.06 0.35 0.28 0.10 0.64 0.19 2.10 0.54 1.85 0.26 2.64 0.52 0.70 1.83JLH03-14 SH-5R 231 ± 3 231 ± 23 0.09 2.48 0.13 0.42 0.61 0.24 3.13 1.03 11.12 3.20 10.94 2.02 16.18 3.17 0.43 4.24JLH03-15 LA-14 197 ± 17 199 ± 41 1.29 35.81 0.81 3.24 0.99 0.17 2.93 0.69 6.86 1.52 5.60 1.17 11.15 2.51 0.28 7.94

Jinluohou garnet-bearing biotite graniteJLH10-01 LA-1 2485 ± 59 2481 ± 72 0.07 25.11 0.25 4.25 6.44 0.99 26.46 7.48 80.02 27.78 116.39 25.01 227.09 44.61 0.20 26.50JLH10-02 SH-1 1858 ± 38 1856 ± 40 0.07 2.19 0.08 0.62 2.56 0.08 13.31 3.62 40.93 15.48 76.66 19.59 212.37 46.29 0.03 5.87JLH10-03 LA-13 2458 ± 28 2459 ± 47 0.05 10.12 0.06 0.87 1.67 0.64 9.20 3.01 37.44 17.07 90.17 21.48 233.10 54.83 0.40 38.23JLH10-04 LA-14 1884 ± 27 1885 ± 55 0.04 0.89 0.05 0.93 1.27 0.09 13.86 3.94 33.02 8.90 30.51 5.69 46.78 9.64 0.04 4.21JLH10-05 SH-2 2929 ± 4 2933 ± 31 0.05 24.79 0.36 5.98 12.43 4.28 61.22 17.86 192.50 63.53 265.53 53.10 496.55 104.42 0.39 18.52JLH10-07 LA-17 1889 ± 43 1892 ± 68 0.06 14.78 0.11 0.64 2.58 0.37 12.52 3.68 36.08 11.28 47.29 9.66 92.87 21.44 0.17 33.18JLH10-08 LA-16 2490 ± 38 2491 ± 37 0.06 38.23 0.35 6.17 8.60 2.51 37.05 10.32 111.47 37.74 157.52 30.61 253.78 48.46 0.36 29.27JLH10-09 SH-5 2485 ± 9 2488 ± 38 0.75 19.65 0.27 2.63 6.52 1.05 46.79 18.19 255.34 106.05 507.19 107.67 1011.80 211.47 0.13 10.27JLH10-10 LA-29 1799 ± 45 1800 ± 57 0.04 0.90 0.05 0.84 4.27 0.09 25.23 5.57 42.54 9.89 33.23 6.63 49.63 9.88 0.02 4.18

a Zircon U–Pb analyses number and data by SHRIMP (SH) or LA-ICP-MS (LA), also can see details in Table 3.b Zircon U–Pb ages get simultaneously with trace elements.

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Table 4U-Th-Pb isotope data for representative zircons from Jinluohou and Jingju granitic complexes.

Zircon U–Pb SHRIMP data

Grain-spot U (ppm) Th (ppm) Th/U f206 (%) Isotopic ratios Ages (Ma)

206Pb*/238U ±1� (%) 207Pb*/235U ±1� (%) 207Pb*/206Pb* ±1� (%) 206Pb/238U ±1� 207Pb/206Pb ±1�

Jingju medium-fine grained K-feldspar graniteJJ03-1 1109 228 0.21 0.229 0.294 0.7 4.64 3.0 0.114 2.9 1663 10 1870 53JJ03-2 454 153 0.35 0.006 0.349 3.0 5.54 3.9 0.115 2.6 1930 49 1883 47JJ03-3 272 62 0.23 0.008 0.387 2.5 6.32 4.0 0.118 3.0 2110 46 1933 54JJ03-4 281 83 0.31 0.000 0.298 0.9 4.64 3.2 0.113 3.1 1681 13 1849 56JJ03-6 169 18 0.11 −0.014 0.576 1.0 13.98 9.0 0.176 8.9 2931 24 2617 148JJ03-9 908 77 0.09 0.010 0.368 3.0 5.71 4.7 0.113 3.6 2021 51 1840 66JJ03-10 274 63 0.24 0.581 0.036 0.9 0.23 4.8 0.046 4.7 228 2 15.9 113JJ03-11 372 66 0.18 0.012 0.230 0.8 3.69 2.6 0.116 2.5 1335 10 1902 45JJ03-12 2588 270 0.11 0.024 0.289 0.6 4.52 0.6 0.114 0.2 1634 9 1859 3JJ03-13 269 70 0.27 −0.050 0.211 0.9 3.21 2.0 0.111 1.8 1232 10 1808 32JJ03-15 347 93 0.28 0.026 0.298 3.4 4.72 7.5 0.115 6.7 1682 50 1878 120JJ03-16 552 138 0.26 0.008 0.370 8.1 5.88 10.7 0.115 6.9 2031 142 1882 124JJ03-17 440 77 0.18 0.130 0.391 1.2 7.51 1.5 0.139 0.8 2129 22 2217 14JJ03-18 286 77 0.28 −0.017 0.340 3.4 4.97 5.8 0.106 4.7 1886 56 1731 86JJ03-19 688 69 0.10 0.004 0.341 7.8 5.59 10.5 0.119 7.1 1892 127 1938 127JJ03-20 234 181 0.80 0.257 0.035 1.3 0.24 4.0 0.050 3.8 223 3 184 88JJ03-31 134 196 1.51 0.043 0.312 7.3 4.97 11.9 0.115 9.3 1752 112 1885 168JJ03-21 233 64 0.28 −0.073 0.272 7.1 4.55 10.5 0.121 7.8 1553 98 1973 138JJ03-14 227 417 1.90 0.000 0.036 0.9 0.26 2.4 0.052 2.3 228 2 296 52JJ03-32 343 149 0.45 −0.072 0.035 0.8 0.26 2.2 0.053 2.0 225 2 330 46JJ03-33 185 116 0.65 1.007 0.035 1.1 0.22 8.2 0.044 8.2 223 2 −89 200JJ03-34R 69 57 0.86 0.000 0.073 8.0 1.00 19.6 0.100 17.9 454 35 1619 333JJ03-35 163 194 1.23 14.173 0.034 3.7 0.03 489.6 0.006 489.6 218 8JJ03-36 166 121 0.75 −0.167 0.037 1.0 0.29 5.2 0.056 5.1 234 2 468 113JJ03-37 159 142 0.92 0.177 0.035 1.1 0.26 4.0 0.053 3.8 223 2 315 87JJ03-38 329 203 0.64 0.300 0.037 1.4 0.26 3.3 0.050 3.0 234 3 210 70JJ03-39 134 113 0.87 0.492 0.034 1.2 0.24 6.7 0.050 6.5 218 3 198 152JJ03-40 176 117 0.69 −0.915 0.034 2.0 0.30 6.5 0.064 6.2 217 4 730 131

Jingju medium-coarse grained K-feldspar graniteJJ05-1 329 82 0.26 0.071 0.297 7.2 4.44 9.1 0.108 5.6 1677 106 1771 102JJ05-2 253 77 0.31 0.047 0.376 4.6 5.95 5.4 0.115 2.7 2055 82 1877 49JJ05-3 455 81 0.18 0.010 0.233 3.5 3.82 5.4 0.119 4.1 1351 43 1940 73JJ05-4 220 177 0.83 0.000 0.358 5.3 5.11 8.4 0.103 6.6 1975 89 1688 121JJ05-5 308 73 0.24 0.029 0.322 2.3 4.80 3.3 0.108 2.4 1801 36 1764 44JJ05-6 256 134 0.54 0.242 0.036 1.6 0.24 4.1 0.047 3.7 231 4 68.7 89JJ05-7 313 57 0.19 0.000 0.404 14.4 6.00 18.6 0.108 11.8 2188 267 1762 216JJ05-8 358 71 0.21 0.013 0.373 1.2 5.94 1.5 0.116 0.9 2042 22 1889 16JJ05-9 257 109 0.44 −0.018 0.364 3.0 5.56 3.6 0.111 1.9 1999 52 1815 35JJ05-10 265 72 0.28 0.000 0.036 0.9 0.25 2.3 0.051 2.1 231 2 226 49JJ05-11 466 332 0.74 0.713 0.038 0.8 0.24 4.5 0.046 4.4 242 2 −16 107JJ05-12 143 126 0.91 0.393 0.036 1.1 0.26 5.3 0.052 5.2 230 2 283 119JJ05-13 298 102 0.36 −0.243 0.036 1.9 0.26 3.3 0.053 2.7 227 4 342 62JJ05-14.1 223 46 0.21 −0.043 0.330 5.9 5.13 5.9 0.113 0.5 1838 94 1845 10JJ05-14.2 614 79 0.13 0.000 0.122 0.7 1.70 3.6 0.101 3.5 743 5 1642 66JJ05-15 50 65 1.34 2.568 0.035 2.0 0.18 27.8 0.036 27.7 225 4 −643 761JJ05-16 332 99 0.31 −0.301 0.037 0.8 0.28 2.9 0.054 2.8 234 2 382 62JJ05-17 244 255 1.08 1.791 0.036 1.0 0.23 17.3 0.047 17.2 227 2 71.0 410JJ05-18 221 199 0.93 0.609 0.036 2.0 0.23 5.6 0.047 5.3 228 4 57.2 126

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Table 4 (Continued)

Zircon U–Pb SHRIMP data

Grain-spot U (ppm) Th (ppm) Th/U f206 (%) Isotopic ratios Ages (Ma)

206Pb*/238U ±1� (%) 207Pb*/235U ±1� (%) 207Pb*/206Pb* ±1� (%) 206Pb/238U ±1� 207Pb/206Pb ±1�

JJ05-19 240 149 0.64 0.471 0.035 1.8 0.23 5.0 0.047 4.7 225 4 56.9 112JJ05-20 359 526 1.52 0.305 0.036 0.8 0.25 3.1 0.051 3.0 226 2 232 70

Jingju porphyritic quartz monzoniteJJ07-1 688 293 0.44 0.426 0.035 0.7 0.24 2.7 0.049 2.6 223 2 145 61JJ07-2 796 311 0.40 −0.067 0.035 1.0 0.25 1.7 0.052 1.4 224 2 285 31JJ07-3 384 133 0.36 0.162 0.035 1.3 0.27 2.8 0.055 2.4 223 3 398 55JJ07-4 694 307 0.46 1.085 0.036 0.7 0.24 4.0 0.047 3.9 229 2 61.9 94JJ07-6 646 235 0.38 −0.134 0.037 1.3 0.26 2.2 0.052 1.8 231 3 264 41JJ07-7 533 307 0.59 0.372 0.036 0.9 0.25 2.9 0.050 2.7 229 2 188 64JJ07-8 1061 677 0.66 0.728 0.036 0.7 0.26 6.9 0.052 6.8 227 2 301 156JJ07-9 503 229 0.47 0.657 0.035 0.8 0.24 3.9 0.049 3.9 224 2 138 91JJ07-10 556 196 0.36 0.055 0.036 1.3 0.25 2.2 0.050 1.8 229 3 210 41JJ07-11 656 272 0.43 0.045 0.036 0.7 0.26 1.7 0.052 1.5 228 2 283 35JJ07-12 873 322 0.38 −0.092 0.036 0.9 0.25 1.6 0.051 1.4 229 2 245 32JJ07-13 940 373 0.41 0.057 0.036 1.1 0.25 1.8 0.050 1.4 229 3 197 32JJ07-14 827 382 0.48 0.105 0.036 0.7 0.25 1.7 0.051 1.5 226 1 222 36JJ07-15 372 65 0.18 0.159 0.036 1.6 0.25 3.0 0.051 2.5 226 4 263 58JJ07-16 543 133 0.25 0.164 0.035 0.8 0.25 2.2 0.052 2.1 221 2 273 48JJ07-17 721 313 0.45 0.211 0.036 0.7 0.25 2.1 0.051 2.0 227 2 245 46

Jinluohou gneissic granodioriteJLH03-1 296 73 0.26 0.043 0.309 1.7 4.87 2.4 0.114 1.7 1734 26 1872 31JLH03-2R 371 80 0.22 0.008 0.314 1.7 4.84 2.0 0.112 1.1 1762 27 1825 20JLH03-2C 120 98 0.84 0.172 0.330 2.1 5.20 2.3 0.114 1.0 1839 34 1868 18JLH03-3 405 105 0.27 0.007 0.311 1.6 4.91 1.8 0.115 0.9 1747 25 1872 16JLH03-4C 248 127 0.53 0.059 0.310 0.9 4.92 1.4 0.115 1.1 1741 14 1880 21JLH03-5R 58 19 0.34 0.000 0.036 1.5 0.26 4.6 0.052 4.3 231 3 270 99JLH03-5C 641 467 0.75 0.012 0.315 0.7 4.98 0.8 0.115 0.3 1767 11 1874 6JLH03-6R 123 69 0.58 0.129 0.331 1.1 5.04 2.2 0.110 1.9 1845 18 1803 34JLH03-7 268 163 0.63 0.010 0.324 1.2 5.10 1.3 0.114 0.5 1811 20 1864 9JLH03-8 298 77 0.27 0.019 0.313 1.8 4.91 2.6 0.114 1.8 1756 28 1859 32JLH03-9 39 8 0.21 4.160 0.035 2.5 0.08 88.1 0.017 88.1 224 5JLH03-9C 195 133 0.70 0.000 0.245 1.4 3.81 1.8 0.113 1.2 1415 18 1840 21JLH03-10 120 69 0.59 14.307 0.252 1.5 4.59 7.0 0.132 6.8 1451 19 2123 119JLH03-11 89 61 0.71 0.170 0.325 1.2 5.15 1.6 0.115 1.0 1813 20 1881 18JLH03-12 25 7 0.30 0.968 0.043 2.4 0.28 18.0 0.048 17.9 269 6 108 422JLH03-13 346 266 0.79 0.031 0.310 0.8 4.89 0.9 0.114 0.4 1741 12 1869 8JLH03-14 181 36 0.21 −0.061 0.268 1.9 4.15 2.1 0.112 0.9 1531 25 1837 16JLH03-15 66 18 0.29 −1.722 0.037 1.7 0.36 10.2 0.069 10.1 236 4 911 207JLH03-16 34 6 0.17 −0.784 0.038 3.3 0.32 11.6 0.062 11.2 241 8 664 239JLH03-17 23 4 0.17 −8.759 0.039 3.9 0.64 19.6 0.118 19.3 248 9 1923 345JLH03-18 120 33 0.29 −0.081 0.225 3.4 3.53 4.4 0.114 2.8 1306 40 1866 50JLH03-19 124 28 0.23 0.187 0.211 2.6 3.08 4.3 0.106 3.4 1235 29 1731 63JLH03-20 41 12 0.30 −0.704 0.039 1.9 0.32 10.9 0.058 10.7 249 5 541 235JLH03-21 156 81 0.54 0.213 0.324 1.5 5.13 1.7 0.115 0.8 1809 24 1877 14

Jinluohou garnet-bearing biotite graniteJLH10-1 398 85 0.22 0.015 0.324 1.8 5.07 2.8 0.114 2.1 1807 28 1858 38JLH10-2 586 47 0.08 0.008 0.396 3.1 11.63 3.1 0.213 0.3 2150 56 2929 4JLH10-3 164 23 0.14 −0.080 0.244 1.0 3.83 1.7 0.114 1.3 1409 13 1859 24JLH10-4 308 127 0.43 0.007 0.433 2.2 9.42 2.7 0.158 1.5 2319 43 2432 26JLH10-5 152 37 0.25 0.152 0.435 2.0 9.75 2.0 0.163 0.5 2326 38 2485 9

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Table 4 (Continued )

Zircon U–Pb LA-ICP-MS data

Grain-spot Th (ppm) U (ppm) Th/U Isotopic ratios Ages (Ma)

206Pb/238U ±1� 207Pb/235U ±1� 207Pb/206Pb ±1� 206Pb/238U ±1� 207Pb/206Pb ±1�

Jinluohou gneissic granodioriteJLH03-01 69 81 0.86 0.29252 0.004 4.65688 0.089 0.11547 0.002 1654 19 1887 35JLH03-02 55 74 0.75 0.32340 0.004 4.96702 0.079 0.11143 0.002 1806 20 1823 28JLH03-03 112 83 1.34 0.31661 0.004 5.00209 0.077 0.11461 0.002 1773 19 1874 27JLH03-04 128 310 0.41 0.27444 0.003 4.25686 0.056 0.11250 0.001 1563 17 1840 22JLH03-05 97 357 0.27 0.23192 0.003 3.56703 0.048 0.11155 0.001 1345 14 1825 22JLH03-06 111 124 0.89 0.29633 0.004 4.74889 0.085 0.11629 0.002 1673 19 1900 32JLH03-07 336 492 0.68 0.31607 0.004 5.02491 0.110 0.11541 0.003 1771 21 1886 40JLH03-08 117 321 0.37 0.26101 0.003 4.06690 0.057 0.11302 0.001 1495 16 1849 24JLH03-09 203 261 0.78 0.22535 0.003 3.48503 0.074 0.11232 0.002 1310 17 1837 39JLH03-10 78 164 0.48 0.31374 0.004 4.95472 0.117 0.11468 0.003 1759 22 1875 44JLH03-11 7 38 0.19 0.04009 0.002 0.42333 0.100 0.07658 0.018 253 13 1110 527JLH03-12 3 13 0.22 0.05021 0.005 0.39888 0.222 0.05771 0.033 316 32 519 1042JLH03-13 12 17 0.71 0.03333 0.003 0.21163 0.115 0.04605 0.025 211 21 922JLH03-14 5 12 0.43 0.03103 0.003 0.23550 0.128 0.05504 0.030 197 17 414 1028JLH03-15 25 57 0.44 0.03675 0.001 0.32861 0.030 0.06490 0.006 233 6 771 205JLH03-16 2 30 0.07 0.03640 0.001 0.26490 0.041 0.05277 0.008 230 8 319 329JLH03-17 146 239 0.61 0.30726 0.004 4.76815 0.070 0.11255 0.002 1727 18 1841 27JLH03-18 1 2 0.33 0.02796 0.009 0.22716 0.740 0.05886 0.193 178 56 562 3725JLH03-19 43 107 0.41 0.28565 0.004 4.35286 0.116 0.11044 0.003 1620 21 1807 53JLH03-20 99 276 0.36 0.24259 0.003 3.68193 0.056 0.11009 0.002 1400 15 1801 28JLH03-21 7 19 0.36 0.03483 0.002 0.39441 0.088 0.08213 0.019 221 10 1249 500

Jinluohou garnet-bearing biotite graniteJLH10-01 271 226 1.20 0.42812 0.007 9.58418 0.305 0.16282 0.006 2297 31 2485 59JLH10-02 100 416 0.24 0.26495 0.003 4.20489 0.060 0.11509 0.002 1515 17 1881 24JLH10-03 171 176 0.97 0.47572 0.005 10.86273 0.181 0.16560 0.003 2509 24 2514 30JLH10-04 72 459 0.16 0.21530 0.003 3.38235 0.080 0.11394 0.003 1257 15 1863 46JLH10-05 97 497 0.20 0.28586 0.004 4.55022 0.072 0.11543 0.002 1621 19 1887 27JLH10-06 171 99 1.73 0.37644 0.005 6.87818 0.161 0.13253 0.003 2060 25 2132 44JLH10-08 589 347 1.70 0.18337 0.002 2.92365 0.050 0.11563 0.002 1085 13 1890 31JLH10-07 86 355 0.24 0.24298 0.003 3.81883 0.061 0.11399 0.002 1402 15 1864 29JLH10-09 56 70 0.80 0.46281 0.008 10.78365 0.358 0.16930 0.006 2452 35 2551 63JLH10-10 104 334 0.31 0.28235 0.003 4.48004 0.069 0.11509 0.002 1603 17 1881 28JLH10-11 48 53 0.91 0.34435 0.006 6.13465 0.178 0.12925 0.004 1908 30 2088 53JLH10-12 83 409 0.20 0.27182 0.003 4.31940 0.086 0.11539 0.002 1550 17 1886 38JLH10-13 184 245 0.75 0.42464 0.006 9.37825 0.159 0.16023 0.003 2282 25 2458 28JLH10-14 62 417 0.15 0.29711 0.004 4.72274 0.073 0.11529 0.002 1677 19 1884 27JLH10-15 111 173 0.64 0.36433 0.006 7.70864 0.181 0.15350 0.004 2003 26 2385 41JLH10-16 424 144 2.95 0.42568 0.006 9.58146 0.208 0.16327 0.004 2286 26 2490 38JLH10-17 104 723 0.14 0.26893 0.004 4.28603 0.101 0.11561 0.003 1535 20 1889 43JLH10-18 54 77 0.70 0.39158 0.005 8.43645 0.141 0.15629 0.003 2130 21 2416 30JLH10-19 77 74 1.05 0.42079 0.007 9.33529 0.339 0.16103 0.006 2264 33 2467 66JLH10-20 96 78 1.24 0.32317 0.005 7.60615 0.178 0.17070 0.004 1805 24 2565 40JLH10-21 51 167 0.30 0.36673 0.005 8.04306 0.124 0.15908 0.002 2014 22 2446 25JLH10-22 44 639 0.07 0.18122 0.002 2.60616 0.055 0.10430 0.003 1074 13 1702 46JLH10-23 408 613 0.66 0.40374 0.005 8.52881 0.116 0.15323 0.002 2186 22 2382 22JLH10-24 56 217 0.26 0.42916 0.006 8.71152 0.165 0.14722 0.003 2302 26 2314 33JLH10-25 147 369 0.40 0.27605 0.003 4.38921 0.066 0.11534 0.002 1571 17 1885 26JLH10-26 180 157 1.14 0.39222 0.005 7.19347 0.112 0.13305 0.002 2133 23 2139 26JLH10-27 74 735 0.10 0.28456 0.004 4.52729 0.086 0.11543 0.002 1614 20 1887 33JLH10-28 139 177 0.79 0.39036 0.005 7.27490 0.118 0.13518 0.002 2124 22 2166 28JLH10-29 126 436 0.29 0.24833 0.004 3.76399 0.090 0.10996 0.003 1430 19 1799 45JLH10-30 98 129 0.76 0.47992 0.006 11.26209 0.231 0.17022 0.003 2527 28 2560 35

Y. Xia et al. / Precambrian Research 2

a

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spect ratios of 1.5–2.0, and smaller than 200 �m × 100 �m. CLmages from the zircons in this sample show core–rim structure.ome euhedral zircon cores show prisms with {1 0 0} > {1 1 0} andyramids with {2 1 1} > {1 0 1}, others are ellipsoidal shape (Fig. 5).hese cores in the zircons show weak zonation or fir-tree struc-ure in CL images. They have 207Pb/206Pb ages ranging from 1731o 1973 Ma and Th/U of 0.09–1.51 with an average of 0.35 (exceptor two inherited cores of JJ03-6 and JJ03-17) (Table 4; Fig. 7). Theirhondrite normalized REE patterns are enriched in HREE with pos-tive Ce anomalies (Ce/Ce* = 2.68–4.39) and negative Eu anomaliesEu/Eu* = 0.03–0.10) (Table 3; Fig. 6). The rims of zircons in thisample are euhedral pyramids or ellipsoidal shapes with weak oro zonation. Some of these rims in zircons are very narrow. Therism faces are {1 1 0} or {1 0 0} less developed; and the pyramid

s often resorbed with {1 0 1} ≥ {2 1 1}. These rims in zircons give06Pb/238U ages ranging from 217 to 234 Ma and Th/U of 0.24–1.90ith an average of 0.83 (Table 4). Except that JJ03-04 has similar REEattern to the cores, the majority of these rims show relatively flatEE patterns and lack positive Ce anomalies (Ce/Ce* = 0.60–1.08),ut still show negative Eu anomalies (Eu/Eu* = 0.02–0.10) (Table 3;ig. 6). Although the majority of data are discordant, a well-efined discordia with an upper intercept at 1884 ± 44 Ma and

ower intercept at 224 ± 63 Ma (MSWD = 1.8) was formed (Fig. 7).f those data which significantly deviate from the discordia arexcluded, the integrated discordia produces an upper intercept agef 1861 ± 35 Ma and a lower intercept of 226 ± 59 Ma (MSWD = 1.5).

Zircons separated from JJ05 are stubby prismatic or ellipsoidaln shape with the range of 250–100 �m in length and 100–40 �mn width. CL images of zircons show that they mostly have simpleompositional zonation and strong resorption, and have core–rimtructure. Those zircons without cores have euhedral morphologyr rounded pyramids and oscillatory or banded zonation, indicat-ng late resorption. The cores and rims in these zircons show similareature to the zircons in the JJ03. The cores in zircons of sample JJ05re more euhedral and bigger than those of sample JJ03 (Fig. 5).he Th/U values of cores in these zircons vary from 0.13 to 0.83,ith an average of 0.30 (Table 4). Most of the cores are enriched

n HREE, and have positive Ce anomalies (Ce/Ce* = 3.98–6.49) andegative Eu anomalies (Eu/Eu* = 0.02–0.03) (Table 3; Fig. 6). The07Pb/206Pb ages of cores range from 1642 to 1940 Ma. Moreover,he Th/U values of rims in these zircons or zircons without coresary from 0.28 to 1.52, on average 0.79 (Table 4). Except JJ05-0 and JJ05-11 have similar REE patterns to the cores, the rest

f them show relatively higher contents of LREE, lack positive Cenomalies (Ce/Ce* = 0.80–4.04) and still show negative Eu anoma-ies (Eu/Eu* = 0.01–0.05) (Table 3; Fig. 6). The 206Pb/238U ages ofims in these zircons or zircons without cores range from 225

16– 219 (2012) 177– 207 187

to 242 Ma (Table 4). According to the analytical data, a discordiayields an upper intercept of 1849 ± 30 Ma and a lower intercept of231.4 ± 6.8 Ma (MSWD = 2.2) (Fig. 7).

4.2.2. Jingju porphyritic quartz monzonite (JJ07)Most of the zircons in the Jingju porphyritic quartz mon-

zonite are euhedral and prismatic, up to 300 �m long. The {1 0 0}prism is developed better than {1 1 0} prism, and the pyramidis truncated, with {1 0 1} > {2 1 1} (Fig. 5). On the CL images,most of these zircons have distinct oscillatory zonation. Theyhave moderately variable abundances of Th (65–677 ppm) and U(372–1061 ppm), and Th/U ratios vary from 0.18 to 0.66 (aver-age 0.42) (Table 4). They also show HREE-enriched patterns withpositive Ce anomalies (Ce/Ce* = 22.19–38.78) and negative Euanomalies (Eu/Eu* = 0.12–0.23) (Table 3; Fig. 6). The 16 analysesyield 206Pb/238U ages from 221 Ma to 231 Ma with a weighted meanat 226.2 ± 1.4 Ma (MSWD = 2.0; Fig. 7), which is consistent with theages of thermal event in other samples.

4.2.3. Jinluohou gneissic granodiorite (JLH03)Zircons separated from this sample are fine prismatic shapes

with abraded pyramids, or ellipsoidal shapes which may implythat the morphology is caused by resorption, rather than mechan-ical abrasion. Most of them are smaller than 250 �m × 100 �m.Similar to the sample JJ03 and JJ05, the CL images show thatmost zircons in this sample exhibit core–rim structures. Therims of these zircons are homogeneous, the pyramid is oftenresorbed with {1 0 0} or {1 0 0} < {1 1 0}, and the prism faces are{2 1 1} or {1 0 0} < {2 1 1}. However, the cores in these zircons havebroad compositional banding or homogeneous internal structure,and well-developed {1 0 1} � {2 1 1} pyramid with {1 1 0} prisms,reflecting crystallization at high temperature from peralkaline tosubalkaline magma (Pupin, 1980; Belousova et al., 2006). Zirconswithout cores have euhedral morphology or rounded pyramidsand oscillatory or banded zonation (Fig. 5). Comparing the Th/Ubetween the cores (varying from 0.21 to 0.84, average 0.49) andthe rims or zircons without cores (varying from 0.17 to 0.34, aver-age 0.25) (Table 4), the rims of these zircons or zircons withoutcores are more compatible with a metamorphic origin, suggest-ing that these zircons probably resulted from the overgrowth orrecrystallization of magmatic zircons during later metamorphism.This is also supported by REE patterns. The cores are enriched inHREE with positive Ce anomalies (Ce/Ce* = 2.95–9.22) and nega-tive Eu anomalies (Eu/Eu* = 0.03–0.08). The rims of these zirconsor zircons without cores show relatively flat REE patterns andweak positive Ce anomalies (Ce/Ce* = 0.69–8.30) and negative Euanomalies (Eu/Eu* = 0.30–1.05) (Table 3; Fig. 6). Twenty-four anal-yses using SHRIMP give 207Pb/206Pb ages ranging from 1731 to1923 Ma (except the most discordant analysis point JLH03-10, witha 207Pb/206Pb age of 2123 Ma, which may be inherited zircon withradiogenic Pb loss) for the cores and 206Pb/238U ages ranging from224 to 269 Ma for the rims or zircons without cores (Table 4),which form a well-defined discordia with an upper intercept at1877 ± 10 Ma and lower intercept at 224 ± 19 Ma (MSWD = 1.8).Meanwhile, Twenty-one analyses using LA-ICP-MS form a discor-dia with an upper intercept at 1868 ± 19 Ma and lower intercept at191 ± 32 Ma (MSWD = 0.65) (Fig. 7).

4.2.4. Jinluohou garnet-bearing biotite granite (JLH10)The Jinluohou garnet-bearing biotite granite contains abundant

zircons. Most of them range 300–100 �m × 150–50 �m in size.CL imaging of zircons shows that they mostly have concentric,

weak oscillatory compositional zonation and core–rim structure.Some of the cores are euhedral and still retain {1 0 1} > {2 1 1}pyramids and {1 1 0} > {1 0 0} prisms (Fig. 5). With a broadrange of Th/U values (from 0.08 to 2.95, average 0.88) (Table 4),

188 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

from

m((ro({0h

Fig. 5. CL images of representative zircons

ost of them are enriched in HREE, have positive Ce anomaliesCe/Ce* = 10.51–40.32) and relatively weak negative Eu anomaliesEu/Eu* = 0.15–0.43) (Table 3; Fig. 6). Thus these cores presumablyepresent inherited zircons. The rims of these zircons appear asvergrowth on the cores and display dark CL and simple zonation

Fig. 5). Most of the rims show well-developed {1 0 0} prisms and2 1 1} pyramids, and have highly variable range of Th/U (from.07 to 1.70, average 0.4) (Table 4), suggesting crystallization atigh temperature in a peraluminous environment (Pupin, 1980;

Jingluohou and Jingju granitic complexes.

Belousova et al., 2006). They also have typical REE patterns ofmagmatic zircons which show enrichment in HREE with positiveCe anomalies (Ce/Ce* = 0.02–0.18) and negative Eu anomalies(Eu/Eu* = 4.47–0.23) (Table 3; Fig. 6). Eighteen analyses done bySHRIMP and LA-ICP-MS on inherited zircon cores exhibit large vari-

207 206

ations of Pb/ Pb ages ranging from 2088 to 2929 Ma becausethey have suffered different extents of non-zero Pb loss. Exceptthree zircons (JLH10-15, JLH10-20 and JLH10-21) may not beconsanguineous, the rest of fifteen analyses distribute along a

Y. Xia et al. / Precambrian Research 2

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ig. 6. Chondrite-normalized REE patterns of zircons from Jinluohou and Jingjuranitic complexes. The chondrite values are from Taylor and McLennan (1985).

ell-defined discordia with an upper intercept age of681 ± 200 Ma and a lower intercept age of 1844 ± 280 MaMSWD = 3.3). The huge error shows the source of the magma mayot be single. Fourteen analyses done by SHRIMP and LA-ICP-MSn overgrowth rims give 207Pb/206Pb ages ranging from 1702o 1890 Ma, and form a discordia yielding an upper intercept of878 ± 28 Ma and a lower intercept of 18 ± 160 Ma (MSWD = 0.43)Fig. 7). A few of zircons have approximately similar ages betweenores and rims (e.g. JLH10-23-the 207Pb/206Pb ages of the cores 2382 Ma and JLH10-24-the 207Pb/206Pb ages of the core is314 Ma; Fig. 7). They may represent the inherited zircons withoutvergrowth or the mixed ages including both core and rim.

.3. Zircons Hf-isotopes

The zircon Hf analyses were done on the same grains as used for–Pb dating (Fig. 5). Analytical results of the Lu–Hf isotopic compo-

itions are given in Table 5 and illustrated in Figs. 8 and 9. We adoptodel Hf ages as either TDM/NC when εHf(t) > 0 or T2DM/NC when

Hf(t) < 0 in subsequent discussions (Zheng et al., 2007). Becauseome zircons without cores in sample JJ03, JJ05 and JLH03 haveges, trace elements and Hf isotope compositions similar to theims, they perhaps are completely recrystallization of protogenesisircons or neogenesis zircons in late metamorphic thermal events.or convenience, these zircons without cores are regarded as theims of those zoning zircons in the following discussion.

Zircons from JJ03, JJ05 and JLH03 show similar Hf-isotope com-ositions. The εHf(t) and initial 176Hf/177Hf ratios for the cores ofircons in these three samples are relatively homogenous. The εHf(t)alues vary from −22.3 to +7.5, clustering within the range of −6 to2 (with weighted means of −2.9 ± 1.1, −3.5 ± 2.9 and −4.4 ± 1.6

2 SD), respectively) (Fig. 8). In addition, the initial 176Hf/177Hfatios range from 0.280957 to 0.281844, corresponding to theepleted mantle Hf model ages (TDM or T2DM) of 1.9–3.96 Ga or theew continental crust Hf model ages (TNC or T2NC) of 1.83–3.87 Ga

16– 219 (2012) 177– 207 189

(Fig. 9). The rims of zircons also exhibit similar εHf(t) values andinitial 176Hf/177Hf ratios. The εHf(t) values vary from −40.0 to−11.1, clustering within the range of −24 to −18 (with weightedmeans of −23.2 ± 5.0, −19.8 ± 5.6 and −20.9 ± 4.8 (2 SD), respec-tively) (Fig. 8). In addition, the initial 176Hf/177Hf ratios range from0.281501 to 0.282318, corresponding to the depleted mantle Hfmodel ages (TDM or T2DM) of 1.96–3.60 Ga or the new continentalcrust Hf model ages (TNC or T2NC) of 1.80–3.50 Ga (Fig. 9).

Inherited zircon cores of JLH10 show different Hf-isotope com-positions in comparison with zircon rims, The cores show highεHf(t) values of −6.8 to +6.9 with a weighted mean of −0.6 ± 2.1and initial 176Hf/177Hf ratios (from 0.281003 to 0.281458); and therims show low εHf(t) values of −17.7 to −3.5 with a weighted meanof −9.0 ± 2.3 (2 SD) and initial 176Hf/177Hf ratios (from 0.281084to 0.281498) (Fig. 8). The inherited zircon cores give the depletedmantle Hf model ages (TDM or T2DM) of 2.45–3.70 Ga or the newcontinental crust Hf model ages (TNC or T2NC) of 2.37–3.60 Ga. Thezircon rims give the depleted mantle Hf model ages (TDM or T2DM)of 2.76–3.67 Ga or the new continental crust Hf model ages (TNC orT2NC) of 2.63–3.57 Ga (Fig. 9).

Zircons from sample JJ07 with a 206Pb/238U age of ca. 226 Mashow varying εHf(t) values of −27.7 to −11.7 with a weighted meanof −19.2 ± 0.8 (2 SD) or initial 176Hf/177Hf ratios (from 0.281846 to0.282119) (Fig. 8), corresponding to the depleted mantle Hf modelages (TDM or T2DM) of 2.34–3.00 Ga or the new continental crust Hfmodel ages (TNC or T2NC) of 2.19–2.87 Ga (Fig. 9).

4.4. Whole-rock major and trace element characteristics

A complete data set of whole-rock major and trace elementanalyses for representative samples from the Jinluohou and Jingjugranitic complexes and some previously published data are listed inTable 6. Data of Southwest Zhejiang Paleoproterozoic S- and A-typegranites together with Cathaysia Paleoproterozoic orthometamor-phic rocks and metasedimentary rocks (Yu et al., 2009; Li et al.,1999, 2000; Wang et al., 1998; Hu et al., 1991) are given in AppendixTable.

All the granitoid samples of Jinluohou and Jingju graniticcomplexes show high SiO2 (between 65.45 and 76.00 wt.%)and relatively high total alkalis with K2O + Na2O (between 6.19and 8.74 wt.%), plotting in the granodiorite and granite fieldson the total alkali-silica (TAS) diagram. The Jingju porphyriticquartz monzonite shows relatively low SiO2 (between 58.06 and59.74 wt.%) and plots in the monzonite fields on TAS diagram(Fig. 10a). Based on the molar ratios of Al2O3/(CaO + Na2O + K2O)(A/CNK) and Al2O3/(Na2O + K2O) (A/NK) (Fig. 10b), the Jinlu-ohou garnet-bearing biotite granite is strongly peraluminous(A/CNK = 1.28–1.42), plotting in the field of Southwest ZhejiangPaleoproterozoic S-type granites. The Jingju K-feldspar graniteand Jinluohou gneissic granodiorite can reach strongly peralu-minous (A/CNK = 0.97–1.26), indicating much higher content ofaluminum than Southwest Zhejiang Paleoproterozoic A-type gran-ites. Furthermore, the Jingju Porphyritic quartz monzonite ismetaluminous (A/CNK = 0.83–0.95). Following Frost et al. (2001),the Jingju K-feldspar granite and Jinluohou gneissic granodioritebelong to ferroan granites that are rich in iron relative to mag-nesium with high FeOT/(FeOT + MgO) (0.77–0.95). In contrast, theJinluohou garnet-bearing biotite granite and Jingju porphyriticquartz monzonite plot in the field of magnesian granites with lowFeOT/(FeOT + MgO) (0.64–0.75) (Fig. 10c). In Fig. 10d, all samplesof Jinluohou and Jingju granitic complexes except for one sample(JLH10) have high K2O (3.17–6.27 wt.%) and very high K2O/Na2O

(1.21–6.39), characteristic mainly of crustal origin. The sampleJLH10 are distinct from other samples with its relatively low K2Ocontent (2.71–2.74 wt.%) and high Na2O (3.58–3.64 wt.%), spread-ing to the field of Cathaysia Paleoproterozoic amphibolites, and

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esearch 216– 219 (2012) 177– 207

Table 5Hf-isotope compositions of zircons from samples of Jinluohou and Jingju granitic complexes.

Analysis no. Age (Ma) 176Hf/177Hf 1 se 176Lu/177Hf 176Yb/177Hf (176Hf/177Hf)i εHf(t) 1 se TDM (Ga) T2DM (Ga) TNC (Ga) T2NC (Ga)

Jinluohou gneissic granodioriteJLH03-01 1877 0.281514 0.000017 0.000404 0.018335 0.28149961 −3.2 0.6 2.40 2.75 2.31 2.61JLH03-02 1877 0.281525 0.000017 0.000739 0.032496 0.28149867 −3.2 0.6 2.40 2.75 2.31 2.61JLH03-03 1872 0.281540 0.000018 0.001240 0.054184 0.28149594 −3.4 0.6 2.41 2.76 2.32 2.62JLH03-04 1877 0.281490 0.000013 0.001169 0.049560 0.28144835 −5.0 0.5 2.48 2.86 2.39 2.73JLH03-05 1825 0.281483 0.000018 0.000385 0.016795 0.28146967 −5.4 0.6 2.44 2.85 2.35 2.72JLH03-06 1868 0.281645 0.000027 0.000312 0.013139 0.28163394 1.4 0.9 2.21 2.45 2.12 2.30JLH03-07 231 0.282221 0.000018 0.000025 0.001033 0.28222089 −14.4 0.6 1.42 2.18 1.31 2.02JLH03-08 1874 0.281710 0.000015 0.001576 0.076262 0.28165394 2.2 0.5 2.20 2.40 2.10 2.25JLH03-09 1872 0.281670 0.000024 0.000571 0.022474 0.28164971 2.0 0.8 2.19 2.41 2.10 2.26JLH03-10 1803 0.281529 0.000018 0.000595 0.025916 0.28150865 −4.5 0.6 2.39 2.78 2.30 2.64JLH03-11 1864 0.281713 0.000016 0.000513 0.023667 0.28169485 3.5 0.6 2.13 2.32 2.04 2.16JLH03-12 1880 0.281505 0.000012 0.000746 0.033581 0.28147838 −3.9 0.4 2.43 2.79 2.34 2.66JLH03-14 1859 0.281500 0.000014 0.000574 0.025014 0.28147975 −4.3 0.5 2.42 2.81 2.34 2.67JLH03-15 224 0.282317 0.000019 0.000024 0.001044 0.28231690 −11.2 0.7 1.29 1.97 1.17 1.80JLH03-16 1840 0.281472 0.000014 0.000750 0.034027 0.28144582 −5.9 0.5 2.47 2.89 2.39 2.76JLH03-17 1877 0.281442 0.000019 0.000891 0.039795 0.28141026 −6.4 0.7 2.52 2.95 2.44 2.82JLH03-18 1877 0.281288 0.000029 0.000897 0.037528 0.28125604 −11.8 1.0 2.73 3.29 2.65 3.18JLH03-19 1877 0.281032 0.000032 0.001302 0.057536 0.28098561 −21.4 1.1 3.11 3.89 3.04 3.80JLH03-20 224 0.281503 0.000026 0.000370 0.016002 0.28150145 −40.0 0.9 2.41 3.75 2.32 3.65JLH03-21 2123 0.281529 0.000018 0.000690 0.035294 0.28150113 2.5 0.6 2.39 2.58 2.30 2.43JLH03-22 1877 0.281542 0.000016 0.001231 0.061408 0.28149814 −3.2 0.6 2.41 2.75 2.32 2.61JLH03-23 249 0.281767 0.000016 0.000289 0.013954 0.28176565 −30.1 0.6 2.05 3.16 1.95 3.05JLH03-24 1877 0.281542 0.000019 0.001122 0.054588 0.28150203 −3.1 0.7 2.40 2.74 2.31 2.60JLH03-25 224 0.281993 0.000029 0.000192 0.009447 0.2819922 −22.7 1.0 1.74 2.68 1.63 2.55JLH03-26 1881 0.281542 0.000015 0.001148 0.055351 0.28150101 −3.0 0.5 2.40 2.74 2.31 2.60JLH03-27 1807 0.281530 0.000019 0.000914 0.044340 0.28149867 −4.8 0.7 2.41 2.8 2.32 2.66JLH03-28 178 0.282098 0.000018 0.000075 0.002696 0.28209775 −19.9 0.6 1.59 2.48 1.48 2.33JLH03-29 1841 0.281561 0.000019 0.000851 0.040543 0.28153127 −2.9 0.7 2.36 2.7 2.27 2.56JLH03-30 230 0.281689 0.000018 0.000580 0.027964 0.28168651 −33.4 0.6 2.17 3.34 2.07 3.24JLH03-31 1887 0.281511 0.000014 0.000539 0.021291 0.28149169 −3.2 0.5 2.41 2.76 2.32 2.62JLH03-32 1874 0.281627 0.000018 0.001092 0.044789 0.28158816 −0.1 0.6 2.28 2.55 2.19 2.40JLH03-33 1880 0.281514 0.000018 0.000605 0.026910 0.28149241 −3.4 0.6 2.41 2.76 2.32 2.62JLH03-34 1869 0.281553 0.000018 0.000744 0.033668 0.28152661 −2.4 0.6 2.36 2.69 2.27 2.55JLH03-35 269 0.281969 0.000017 0.000048 0.002019 0.28196876 −22.5 0.6 1.76 2.71 1.66 2.57JLH03-36 1900 0.281546 0.000018 0.000549 0.024573 0.28152620 −1.7 0.6 2.36 2.67 2.27 2.53JLH03-37 1825 0.281597 0.000018 0.000612 0.026926 0.28157581 −1.7 0.6 2.30 2.61 2.20 2.47JLH03-38 1886 0.281608 0.000014 0.001215 0.055529 0.28156450 −0.7 0.5 2.32 2.6 2.22 2.45JLH03-39 1849 0.281515 0.000016 0.000494 0.022378 0.28149767 −3.9 0.6 2.40 2.77 2.31 2.63JLH03-40 1837 0.281537 0.000015 0.000661 0.029510 0.28151396 −3.6 0.5 2.38 2.74 2.29 2.60JLH03-41 1837 0.281646 0.000021 0.000485 0.020575 0.28162910 0.5 0.7 2.22 2.48 2.13 2.33JLH03-42 236 0.281702 0.000025 0.000585 0.026203 0.28169942 −32.8 0.9 2.15 3.31 2.06 3.20JLH03-43 248 0.281974 0.000017 0.000014 0.000474 0.28197394 −22.8 0.6 1.75 2.71 1.65 2.57JLH03-44 1875 0.281557 0.000016 0.001084 0.044699 0.28151842 −2.6 0.6 2.38 2.71 2.29 2.57JLH03-45 241 0.282015 0.000019 0.000211 0.009358 0.28201405 −21.5 0.7 1.71 2.63 1.60 2.49JLH03-46 241 0.282158 0.000019 0.000131 0.004841 0.28215741 −16.5 0.7 1.51 2.31 1.40 2.16

Jinluohou garnet-bearing biotite graniteJLH10-01 2565 0.281013 0.000016 0.000877 0.040275 0.28097003 −6.2 0.6 3.10 3.47 3.03 3.36JLH10-02 2446 0.281223 0.000018 0.000369 0.013450 0.28120578 −0.6 0.6 2.78 3.02 2.71 2.89JLH10-03 2382 0.281236 0.000018 0.000929 0.039826 0.2811938 −2.5 0.6 2.81 3.09 2.73 2.97JLH10-04 2314 0.281390 0.000013 0.000735 0.028141 0.28135759 1.8 0.5 2.58 2.77 2.50 2.63JLH10-05 2139 0.281499 0.000016 0.001007 0.044059 0.28145802 1.3 0.6 2.45 2.66 2.37 2.52JLH10-06 1885 0.281515 0.000020 0.001017 0.044967 0.28147861 −3.7 0.7 2.43 2.79 2.34 2.65JLH10-07 1887 0.281270 0.000020 0.000466 0.019725 0.28125331 −11.7 0.7 2.73 3.29 2.65 3.18JLH10-08 2416 0.281136 0.000019 0.000396 0.015087 0.28111775 −4.4 0.7 2.9 3.24 2.83 3.12

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Table 5 (Continued)

Analysis no. Age (Ma) 176Hf/177Hf 1 se 176Lu/177Hf 176Yb/177Hf (176Hf/177Hf)i εHf(t) 1 se TDM (Ga) T2DM (Ga) TNC (Ga) T2NC (Ga)

JLH10-09 2467 0.281437 0.000015 0.000755 0.030619 0.28140145 6.9 0.5 2.52 2.56 2.44 2.41JLH10-10 2166 0.281209 0.000021 0.000852 0.037596 0.28117388 −8.2 0.7 2.84 3.29 2.76 3.17JLH10-11 1799 0.281313 0.000027 0.000280 0.011165 0.28130345 −11.9 0.9 2.66 3.24 2.58 3.12JLH10-12 2485 0.281300 0.000019 0.002072 0.082595 0.28120171 0.2 0.7 2.80 3.00 2.72 2.88JLH10-13 2490 0.281044 0.000018 0.000868 0.036545 0.28100274 −6.8 0.6 3.06 3.45 2.99 3.34JLH10-14 1889 0.281096 0.000019 0.000348 0.012852 0.28108352 −17.7 0.7 2.95 3.67 2.88 3.57JLH10-15 1859 0.281243 0.000019 0.000588 0.022457 0.28122226 −13.4 0.7 2.77 3.38 2.69 3.27JLH10-16 2929 0.280806 0.000017 0.000877 0.036266 0.28075676 −5.4 0.6 3.38 3.70 3.32 3.60JLH10-17 2432 0.281367 0.000018 0.001540 0.059848 0.28129554 2.3 0.6 2.67 2.83 2.59 2.69JLH10-18 2385 0.281330 0.000018 0.000745 0.031167 0.28129611 1.2 0.6 2.67 2.86 2.58 2.73JLH10-19 2458 0.281228 0.000020 0.000529 0.020428 0.28120319 −0.4 0.7 2.79 3.02 2.71 2.89JLH10-20 1884 0.281416 0.000017 0.000482 0.018209 0.28139876 −6.6 0.6 2.53 2.97 2.45 2.84JLH10-21 1886 0.281467 0.000015 0.001054 0.041416 0.28142927 −5.5 0.5 2.50 2.90 2.41 2.77JLH10-22 1890 0.281178 0.000017 0.000414 0.018985 0.28116315 −14.8 0.6 2.85 3.49 2.77 3.39JLH10-23 1864 0.281510 0.000026 0.000331 0.013035 0.28149829 −3.5 0.9 2.40 2.76 2.31 2.62JLH10-24 2551 0.281169 0.000019 0.000634 0.027262 0.28113811 −0.6 0.7 2.88 3.10 2.80 2.98JLH10-25 1881 0.281357 0.000018 0.000283 0.011846 0.28134690 −8.5 0.6 2.60 3.09 2.52 2.96JLH10-26 2514 0.281311 0.000024 0.000839 0.032823 0.28127073 3.3 0.8 2.70 2.83 2.62 2.69JLH10-27 1863 0.281348 0.000017 0.000463 0.019451 0.28133163 −9.5 0.6 2.62 3.13 2.54 3.01JLH10-28 1887 0.281437 0.000019 0.000215 0.009319 0.28142930 −5.5 0.7 2.49 2.90 2.40 2.77JLH10-29 2132 0.281371 0.000026 0.001004 0.044881 0.28133027 −3.4 0.9 2.63 2.96 2.54 2.83JLH10-30 1858 0.281452 0.000017 0.000863 0.034013 0.28142157 −6.4 0.6 2.51 2.94 2.42 2.81JLH10-31 2485 0.281358 0.000017 0.000551 0.023158 0.28133186 4.8 0.6 2.62 2.71 2.53 2.57JLH10-32 1881 0.281420 0.000017 0.000264 0.01116 0.28141057 −6.3 0.6 2.51 2.95 2.43 2.82JLH10-33 1882 0.281310 0.000019 0.001038 0.04215 0.28127292 −11.1 0.7 2.71 3.25 2.63 3.14

Jingju medium-fine grained K-feldspar graniteJJ03-01 1883 0.281588 0.000014 0.001225 0.057097 0.28154422 −1.5 0.5 2.35 2.64 2.25 2.50JJ03-02 217 0.282216 0.000022 0.000919 0.038772 0.28221227 −15 0.8 1.46 2.20 1.34 2.05JJ03-03 1933 0.281626 0.000018 0.001314 0.058582 0.28157777 0.9 0.6 2.3 2.53 2.20 2.39JJ03-04 1849 0.281847 0.000017 0.001856 0.083360 0.28178188 6.2 0.6 2.02 2.13 1.92 1.96JJ03-05 1870 0.281523 0.000012 0.000815 0.039264 0.28149408 −3.5 0.4 2.41 2.77 2.32 2.63JJ03-06 1933 0.281565 0.000016 0.001216 0.054055 0.28152036 −1.2 0.6 2.38 2.66 2.29 2.52JJ03-07 1849 0.281495 0.000020 0.001502 0.068886 0.28144230 −5.9 0.7 2.49 2.90 2.40 2.76JJ03-08 218 0.282156 0.000016 0.000761 0.034257 0.28215290 −17.1 0.6 1.54 2.33 1.42 2.18JJ03-09 1840 0.281690 0.000015 0.000590 0.023240 0.28166940 2.0 0.5 2.17 2.39 2.07 2.24JJ03-10 1840 0.281532 0.000018 0.000452 0.019239 0.28151622 −3.4 0.6 2.37 2.74 2.29 2.60JJ03-11 223 0.282158 0.000020 0.000605 0.026733 0.28215548 −16.9 0.7 1.53 2.32 1.42 2.17JJ03-12 234 0.282120 0.000022 0.000640 0.027823 0.28211720 −18 0.8 1.58 2.40 1.47 2.25JJ03-13 1840 0.281569 0.000016 0.000088 0.004310 0.28156593 −1.7 0.6 2.30 2.62 2.21 2.48JJ03-14 228 0.282248 0.000015 0.000122 0.005638 0.28224748 −13.6 0.5 1.39 2.12 1.27 1.96JJ03-15 1878 0.281360 0.000019 0.000988 0.045336 0.28132478 −9.4 0.7 2.64 3.14 2.56 3.02JJ03-16 1878 0.281325 0.000015 0.000832 0.040065 0.28129534 −10.4 0.5 2.68 3.21 2.60 3.09JJ03-17 1859 0.281582 0.000031 0.000472 0.021971 0.28156535 −1.3 1.1 2.31 2.61 2.22 2.47JJ03-19a 1808 0.281865 0.000026 0.000604 0.030264 0.28184429 7.5 0.9 1.93 2.01 1.83 1.84JJ03-19b 1808 0.281266 0.000029 0.000829 0.039461 0.28123757 −14.1 1.0 2.76 3.38 2.68 3.27JJ03-20 228 0.281573 0.000016 0.001355 0.061445 0.28156723 −37.6 0.6 2.37 3.60 2.28 3.50JJ03-21 1882 0.281109 0.000014 0.000898 0.044351 0.28107692 −18.1 0.5 2.98 3.69 2.90 3.59JJ03-22 1882 0.280991 0.000017 0.000961 0.046733 0.28095667 −22.3 0.6 3.14 3.96 3.07 3.87JJ03-23 1731 0.281537 0.000014 0.000546 0.025339 0.28151909 −5.8 0.5 2.37 2.8 2.28 2.67JJ03-24 2217 0.281585 0.000016 0.000713 0.029379 0.28155490 6.6 0.6 2.32 2.39 2.23 2.23JJ03-25 1885 0.281542 0.000014 0.000405 0.019497 0.28152751 −2.0 0.5 2.36 2.68 2.27 2.54JJ03-27 225 0.282128 0.000026 0.001018 0.040936 0.28212372 −18 0.9 1.59 2.39 1.47 2.24JJ03-28 223 0.282103 0.000019 0.001345 0.054833 0.28209739 −19 0.7 1.63 2.45 1.52 2.31JJ03-29 1938 0.281544 0.000014 0.000846 0.043081 0.28151286 −1.3 0.5 2.38 2.68 2.29 2.54JJ03-30 1619 0.281674 0.000023 0.000164 0.008597 0.28166897 −3.0 0.8 2.17 2.54 2.07 2.39JJ03-31 1973 0.281666 0.000018 0.000871 0.043064 0.28163335 3.8 0.6 2.22 2.38 2.12 2.23

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Table 5 (Continued)

Analysis no. Age (Ma) 176Hf/177Hf 1 se 176Lu/177Hf 176Yb/177Hf (176Hf/177Hf)i εHf(t) 1 se TDM (Ga) T2DM (Ga) TNC (Ga) T2NC (Ga)

JJ03-32 1884 0.281554 0.000018 0.000868 0.042991 0.28152296 −2.2 0.6 2.37 2.69 2.28 2.56JJ03-33 1884 0.281544 0.000015 0.001034 0.050963 0.28150702 −2.8 0.5 2.39 2.73 2.30 2.60JJ03-34 218 0.282098 0.000016 0.000679 0.029609 0.28209523 −19.2 0.6 1.61 2.46 1.50 2.31JJ03-35 234 0.282195 0.000031 0.000802 0.033974 0.28219149 −15.4 1.1 1.48 2.24 1.37 2.08JJ03-36 1884 0.281650 0.000021 0.000307 0.015518 0.28163902 1.9 0.7 2.21 2.43 2.11 2.29

Jingju medium-coarse grained K-feldspar graniteJJ05-01 1771 0.281541 0.000014 0.001025 0.048928 0.28150658 −5.3 0.5 2.40 2.80 2.31 2.67JJ05-02 1877 0.281539 0.000015 0.000930 0.043794 0.28150587 −3.0 0.5 2.39 2.73 2.30 2.59JJ05-03 1940 0.281570 0.000013 0.000783 0.035940 0.28154115 −0.3 0.5 2.34 2.61 2.25 2.47JJ05-04 1849 0.281520 0.000019 0.001175 0.053121 0.28147877 −4.6 0.7 2.44 2.81 2.35 2.68JJ05-05 1688 0.281501 0.000019 0.000152 0.007054 0.28149614 −7.6 0.7 2.40 2.88 2.31 2.75JJ05-06 1762 0.281625 0.000014 0.000786 0.038537 0.28159874 −2.3 0.5 2.27 2.60 2.18 2.46JJ05-07 231 0.282119 0.000017 0.000908 0.034202 0.28211508 −18.2 0.6 1.59 2.41 1.48 2.26JJ05-08 1764 0.281534 0.000017 0.000797 0.037069 0.28150734 −5.5 0.6 2.39 2.81 2.30 2.67JJ05-09 1889 0.281524 0.000018 0.000801 0.038002 0.28149528 −3.1 0.6 2.41 2.75 2.32 2.61JJ05-10 1815 0.281474 0.000018 0.000784 0.037972 0.28144701 −6.5 0.6 2.47 2.91 2.39 2.78JJ05-11 1845 0.281539 0.000015 0.000766 0.039307 0.28151218 −3.5 0.5 2.38 2.74 2.29 2.60JJ05-12 1642 0.281581 0.000012 0.000092 0.004831 0.28157814 −5.7 0.4 2.29 2.73 2.20 2.59JJ05-13 1845 0.281465 0.000013 0.000796 0.039347 0.28143713 −6.1 0.5 2.49 2.91 2.40 2.78JJ05-14 225 0.282319 0.000020 0.000168 0.009457 0.28231829 −11.1 0.7 1.29 1.96 1.17 1.80JJ05-15 1849 0.281560 0.000013 0.000040 0.002911 0.2815586 −1.7 0.5 2.31 2.63 2.22 2.49JJ05-16 1849 0.281582 0.000013 0.000078 0.003634 0.28157926 −1.0 0.5 2.28 2.59 2.19 2.44JJ05-17 231 0.281657 0.000016 0.000350 0.018647 0.28165549 −34.4 0.6 2.20 3.41 2.11 3.30JJ05-18 231 0.282093 0.000022 0.001025 0.043362 0.28208857 −19.1 0.8 1.63 2.47 1.52 2.32JJ05-19 234 0.282085 0.000024 0.000983 0.040533 0.28208070 −19.3 0.8 1.64 2.48 1.53 2.34JJ05-20 242 0.282161 0.000016 0.000657 0.028203 0.28215803 −16.4 0.6 1.53 2.31 1.41 2.16JJ05-21 230 0.282079 0.000018 0.000773 0.033054 0.28207568 −19.6 0.6 1.64 2.5 1.53 2.35JJ05-22 1849 0.281425 0.000018 0.001074 0.054080 0.28138732 −7.8 0.6 2.56 3.02 2.47 2.89JJ05-23 226 0.282126 0.000025 0.001140 0.044662 0.28212118 −18.1 0.9 1.59 2.40 1.48 2.25JJ05-24 227 0.282070 0.000026 0.001006 0.042583 0.28206573 −20.0 0.9 1.67 2.52 1.56 2.38JJ05-26 228 0.281953 0.000015 0.001183 0.049181 0.28194796 −24.2 0.5 1.84 2.78 1.73 2.64JJ05-27 1849 0.281296 0.000017 0.001534 0.066285 0.28124218 −13.0 0.6 2.77 3.34 2.69 3.23

Jingju porphyritic quartz monzoniteJJ07-01 227 0.282089 0.000018 0.000821 0.043826 0.28208552 −19.3 0.6 1.63 2.48 1.52 2.33JJ07-02 221 0.282107 0.000011 0.000571 0.024379 0.28210464 −18.8 0.4 1.60 2.44 1.49 2.29JJ07-03 226 0.282070 0.000017 0.000506 0.023207 0.28206786 −20.0 0.6 1.64 2.52 1.54 2.37JJ07-04 229 0.282102 0.000015 0.000716 0.033227 0.28209894 −18.8 0.5 1.61 2.45 1.50 2.30JJ07-05 226 0.282122 0.000014 0.000950 0.045830 0.28211799 −18.2 0.5 1.59 2.41 1.48 2.26JJ07-06 228 0.282032 0.000018 0.000683 0.031921 0.28202909 −21.3 0.6 1.70 2.60 1.60 2.46JJ07-07 229 0.282101 0.000019 0.000622 0.030172 0.28209834 −18.8 0.7 1.61 2.45 1.50 2.30JJ07-08 229 0.282121 0.000018 0.000669 0.032466 0.28211814 −18.1 0.6 1.58 2.40 1.47 2.25JJ07-09 228 0.282088 0.000013 0.000769 0.036618 0.28208472 −19.3 0.5 1.63 2.48 1.52 2.33JJ07-10 224 0.282096 0.00002 0.000673 0.032324 0.28209318 −19.1 0.7 1.62 2.46 1.51 2.32JJ07-11 226 0.282151 0.000017 0.000729 0.034597 0.28214792 −17.1 0.6 1.54 2.34 1.43 2.19JJ07-12 226 0.282122 0.000014 0.000717 0.034579 0.28211897 −18.1 0.5 1.58 2.4 1.47 2.25JJ07-13 226 0.282138 0.000018 0.000999 0.047465 0.28213378 −17.6 0.6 1.57 2.37 1.46 2.22JJ07-14 227 0.282100 0.000012 0.001222 0.057906 0.28209482 −19.0 0.4 1.63 2.46 1.52 2.31JJ07-15 231 0.281849 0.000020 0.000678 0.031571 0.28184607 −27.7 0.7 1.96 3.00 1.85 2.87JJ07-16 226 0.282099 0.000013 0.000676 0.032000 0.28209614 −19.0 0.5 1.61 2.45 1.50 2.31JJ07-17 229 0.282050 0.000017 0.001219 0.043275 0.28204478 −20.7 0.6 1.70 2.56 1.59 2.42JJ07-18 223 0.282120 0.000018 0.000662 0.030776 0.28211724 −18.3 0.6 1.58 2.41 1.47 2.26JJ07-19 229 0.282106 0.000017 0.001191 0.057103 0.28210090 −18.7 0.6 1.62 2.44 1.51 2.29JJ07-20 224 0.282099 0.000016 0.001124 0.051572 0.28209429 −19.1 0.6 1.63 2.46 1.52 2.31JJ07-21 223 0.282081 0.000014 0.000823 0.038193 0.28207757 −19.7 0.5 1.64 2.50 1.53 2.35

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Table 6Chemical compositions of representative samples from Jinluohou and Jingju granitic complexes.

Sample JLH03 JLH04 JLH06 3534-1d JLH08 JLH09 JLH10-1 JLH10-2 3544-1d JJ03 4170-1d LF-29d JJ05 4015-1d LF-12d JJ06 JJ07 3116-1d LF-9d

Major elements (wt.%)SiO2 68.51 76.00 69.41 67.44 65.45 66.47 71.13 71.62 70.20 71.58 77.08 71.18 70.73 70.69 68.34 59.74 58.06 61.08 58.50TiO2 0.69 0.67 0.72 0.60 0.88 0.57 0.25 0.25 0.38 0.40 0.20 0.19 0.42 0.40 0.42 0.79 0.99 0.65 0.87Al2O3 13.00 9.12 13.55 14.38 15.73 14.98 14.24 14.14 13.79 13.84 11.09 13.32 14.09 14.72 14.27 14.89 15.34 16.08 15.48Fe2O3

T 6.28 5.00 4.36 5.77 5.31 5.34 3.16 3.23 4.18 2.61 2.30 3.68 2.46 2.27 4.41 6.96 7.91 5.66 7.93MnO 0.29 0.08 0.05 0.05 0.10 0.07 0.09 0.08 0.05 0.02 0.03 0.07 0.02 0.02 0.04 0.10 0.10 0.09 0.13MgO 0.61 0.78 0.61 0.85 1.56 2.06 1.48 1.13 1.85 0.36 0.10 0.18 0.48 0.62 0.67 3.43 3.88 2.88 3.63CaO 2.00 1.44 1.91 2.07 1.86 1.62 1.11 1.07 1.07 0.33 0.36 0.77 0.95 0.96 1.74 4.32 4.32 3.93 4.80Na2O 2.06 0.69 2.35 2.65 2.47 2.42 3.64 3.58 2.62 2.40 2.09 2.08 2.61 2.52 2.87 2.52 3.21 2.69 3.12K2O 5.05 4.40 5.22 4.62 4.51 3.78 2.74 2.71 3.17 6.22 5.55 6.95 6.13 5.36 6.27 5.45 4.29 4.92 4.11P2O5 0.21 0.18 0.21 0.26 0.11 0.08 0.08 0.08 0.10 0.16 0.03 0.03 0.18 0.21 0.15 0.38 0.44 0.35 0.40LOI 1.35 1.26 1.37 1.40 1.68 2.32 1.81 2.04 2.38 1.61 1.08 1.38 1.47 1.74 0.58 1.13 1.17 1.13 0.88Total 100.04 99.60 99.75 100.09 99.68 99.70 99.74 99.93 99.79 99.53 99.91 99.83 99.55 99.51 99.76 99.70 99.71 99.46 99.85A/CNKa 1.04 1.07 1.04 1.10 1.28 1.36 1.30 1.31 1.42 1.23 1.10 1.08 1.11 1.26 0.97 0.83 0.86 0.95 0.85

Trace elements (ppm)V 20.41 18.90 20.10 101.01 70.42 26.46 11.28 12.45 104.52 119.28Cr 14.15 14.11 13.88 50.03 127.33 54.92 6.04 4.87 81.79 93.20Ni 6.17 4.58 4.71 34.80 53.17 16.36 2.52 2.17 17.7 23.7Ga 24.18 16.71 22.60 22.77 20.36 17.87 27.39 27.30 22.35 26.39Rb 184 183 233 178 181 130 322 316 179 291Sr 168 146 194 325 281 326 104 124 804 866Y 51.14 46.46 36.00 30.55 30.24 26.11 16.47 14.76 44.10 34.60Zr 298 218 301 244 181 136 277 282 290 250Nb 18.66 18.55 17.41 26.76 16.11 8.16 16.88 15.51 19.55 22.55Cs 0.78 0.83 1.58 2.96 4.88 2.77 2.50 2.46 3.82 8.87Ba 911 636 755 828 709 429 468 488 1650 972La 94.69 64.09 76.67 106.79 45.68 44.20 113.07 124.39 84.57 93.92Ce 178.09 120.99 146.40 248.45 93.87 86.40 201.26 257.33 157.99 174.69Pr 20.29 14.49 17.67 30.51 10.65 10.12 28.87 33.01 18.95 19.78Nd 75.80 55.67 67.63 120.31 40.17 37.86 96.39 109.45 73.02 71.69Sm 13.50 10.52 12.52 25.04 8.08 7.91 15.11 16.72 14.06 12.20Eu 1.69 1.36 1.52 1.54 1.25 1.00 0.82 0.89 2.76 2.27Gd 12.10 9.05 9.88 16.80 6.21 6.10 9.42 10.21 11.60 9.96Tb 1.74 1.33 1.34 1.85 0.84 0.84 1.04 1.08 1.60 1.31Dy 9.61 7.72 6.73 7.12 4.71 4.59 3.92 3.88 8.38 6.46Ho 1.86 1.52 1.21 1.09 1.07 0.90 0.60 0.57 1.51 1.16Er 5.53 4.49 3.51 2.93 3.45 2.67 1.65 1.57 4.13 3.27Tm 0.82 0.66 0.47 0.31 0.53 0.38 0.19 0.16 0.58 0.41Yb 6.10 4.53 3.18 1.97 3.64 2.80 1.13 1.05 3.82 2.82Lu 0.89 0.62 0.44 0.27 0.57 0.42 0.15 0.13 0.53 0.39Hf 8.13 6.06 8.38 6.53 5.10 3.74 8.00 7.98 8.15 6.52Ta 1.43 1.08 1.21 1.44 0.68 0.40 1.29 1.18 1.66 1.38Pb 131.57 19.33 35.60 44.42 26.05 21.89 43.33 44.13 32.80 33.06Th 24.27 26.35 31.30 88.80 29.25 23.55 70.14 67.68 22.54 19.30U 0.62 2.22 1.97 4.35 2.12 1.88 3.03 4.88 4.00 2.48Eu/Eud,b 0.40 0.42 0.40 0.22 0.52 0.43 0.20 0.19 0.64 0.61(La/Yb)N 10.5 9.56 16.3 36.6 8.49 10.7 67.4 80.4 14.9 22.5∑

REE 423 297 349 565 221 206 474 560 383 400T (◦C)c 840 842 809 792 854 844 786 774

a A/CNK = molar Al2O3/(CaO + Na2O + K2O).b Eu/Eu* = 2 × EuN/(SmN + GdN).c Temperature (◦C) is calculated after Watson and Harrison (1983).d After the 7th Geological Brigade of Zhejiang Province, 2001. Report on Regional Geological Survey of Jingjukou (1/50,000), 15–24.

194 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

01HLJ01HLJ

n=152681±200 Ma(2σ)

MSWD=3.31844±280 Ma(2σ)

n=141878 28 Ma(2σ )

MSWD=0.43

±18±160 Ma(2σ)

JJ03

n=201861±35 Ma(2σ)

MSWD=1.5226±59 Ma(2σ)

JJ05

n=211849 30 Ma(2σ )

MSWD=2.2

±231.4±6.8 Ma(2σ)

n=16226.2±1.4 Ma(2σ)MSWD=2.0

JJ07 JLH03

n=241877±10 Ma(2σ)

MSWD=1.8224±19 Ma(2σ)

220

224

228

232

JJ03-6

JJ03-17

JLH10-2

JLH10-21

JLH10-20

JLH10-15

JLH03-10

210

200

220

230

240

250

260

0.3

0.2

0.1

0.00 4 8 12 16

3000

2000.0

0.2

0.4

0.6

0 2 4 6 8 10

1000

207 23 5Pb/ U

207 23 5Pb/ U

83

26

02

U/

bP

83

26

02

U/

bP

83

26

02

U/

bP

0.0

0.1

0.2

0.3

0.4

200

1000

1800

0 2 4 6

0 2 4 6 8 10 12 14

0.5

0.4

0.3

0.2

0.1

0.0

1800

2200

2600

600

1000

1800

1400

0.0

0.1

0.2

0.3

0.4

0 2 4 6

1000

1400

0.031

0.029

0.033

0.035

0.037

0.039

0.041

0.220.20 0.2 4 0.2 6 0.3 00.28

2600

2200

1800

1400

0.5

0.4

20

200

1400

1800

2200

1400

0.5

0.3

0.1

n=211868±19 Ma(2σ)

MSWD=0.65191±32 Ma(2σ)

200

1000

1800

1400

cores rim s

SHIMP

LA-ICP-MS

F ju grad

sg

gmpm

ig. 7. U–Pb Concordia diagram of representative zircons from Jingluohou and Jingotted line ellipses indicate the LA-ICP-MS analysis spots.

how a likely mantle-derived magma contamination in Jinluohouarnet-bearing biotite granite.

In Harker diagrams (Fig. 11), all samples of Jinluohou and Jingju

ranitic complexes display a negative correlation between someajor elements (such as CaO, Fe2O3, TiO2, MgO and MnO) and SiO2,

lotting in the fields of metasedimentary rocks, felsic orthometa-orphic rocks and amphibolites, consistent with the trend of

nitic complexes. The solid line ellipses indicate the SHRIMP analysis spots, and the

Southwest Zhejiang Paleoproterozoic S- and A-type granites. InK2O–SiO2 and K2O–Na2O diagrams, all samples of Jinluohou andJingju granitic complexes together with Southwest Zhejiang Pale-

oproterozoic S- and A-type granites plot in the shoshonitic andhigh-K calc-alkaline fields (Fig. 10d). Jingju K-feldspar granite andJinluohou gneissic granodiorite are relatively high in P2O5, andshow negative correlation between P2O5 and SiO2, characteristic of

Y. Xia et al. / Precambrian Research 2

re

bm

uN

εHf

( )t

16

12

8

4

-50 -4 0 -3 0 -2 0 -10 0 10 20 30

JJ07

5

3

1

JJ05

6

4

2

JJ03

1

2

3

4JLH10

10

14

6

2

JLH03coresrims

FJ

IgS

oabhagtnmcautp

ig. 8. Histograms of εHf(t) values for representative zircons from Jingluohou andingju granitic complexes.

- and A-type granites. In contrary, Jinluohou garnet-bearing biotiteranite is relatively low in P2O5, and shows no correlation withiO2, characteristic of S-type granites (Chappell, 1999).

The Jingju K-feldspar granite and Jinluohou gneissic granodi-rite are enriched in HFSE (Zr, Hf, Nb, Ta), Rb, Ga and Zn, andre poor in Sr, Cs and Th. In contrast, the Jinluohou garnet-earing biotite granite and Jingju porphyritic quartz monzoniteave relatively low contents of HFSE, Rb, and Ga, and are rel-tively rich in Sr (Table 6). All samples of Jinluohou and Jingjuranitic complexes show similar chondrite-normalized REE pat-erns with relative enrichment of LREE over HREE with significantegative Eu anomalies (Eu/Eu* = 0.19–0.64), suggesting that theagma may have undergone subsequent fractionation of plagio-

lase and K-feldspar fractionation, and the total REE for all samples

re high (�REE = 221–565 ppm) (Fig. 12a and b). The (La/Yb)CN val-es are higher in Jingju K-feldspar granite (67.40–80.42) than inhe rest of the samples from Jinluohou and Jingju granitic com-lexes (8.49–22.51) (Fig. 12b). In the primitive mantle-normalized

16– 219 (2012) 177– 207 195

trace element diagrams (Fig. 12c and d), they are all characterizedby negative Ba, Nb and Ta anomalies and marked depletion in Sr,P and Ti. The negative P and Ti anomalies indicate that fractiona-tion of apatite and Fe-Ti oxides also occurred in magma evolution.But Jingju porphyritic quartz monzonite has smaller anomalies inBa, Sr, P and Eu, which is consistent with those rocks being cumu-late (e.g., the effect of fractionation/accumulation of plagioclase andapatite). All the granites are characterized by enrichments in K,Rb, Ba, Th, Ce and Sm relative to Ta, Nb, Hf, Zr, Y and Yb, exhibit-ing patterns typical of volcanic arc granites. Nevertheless, all thesamples of Jinluohou and Jingju granitic complexes and Paleopro-terozoic S- and A-type granites have REE patterns and trace elementdiagrams similar to Paleoproterozoic metasedimentary rocks andfelsic orthometamorphic rocks, suggesting the possibility that theyare mainly derived from the crustal material.

4.5. Nd-isotope compositions

The whole-rock Nd isotopic data of the Jinluohou and Jingjugranitic complexes are given in Table 7.

Jingju K-feldspar granite have relatively higher εNd(t) valuesranging from 0.5 to 0.7. The εNd(t) of Jinluohou gneissic granodi-orite vary from −4.4 to −5.7. The Jinluohou garnet-bearing biotitegranite shows εNd(t) values ranging from −6.7 to −8.5. The youngJingju porphyritic quartz monzonite have low εNd(t) values rangingfrom −14.2 to −15.1 (Fig. 13a).

Jinluohou gneissic granodiorite, Jinluohou garnet-bearingbiotite granite and Jingju porphyritic quartz monzonite are well dis-tributed along the terrestrial array (Vervoort et al., 1999), whereasJingju K-feldspar granite plots below the previously defined terres-trial array, displaying a Hf–Nd decoupling (Fig. 13b). Consideringthe Sm–Nd isotopic system of Jingju K-feldspar granite may be dis-turbed (see discussion below), the zircon Lu–Hf isotopic system canreliably elucidate the nature of its magma sources (Hawkesworthand Kemp, 2006).

5. Discussion

5.1. The ages of Paleoproterozoic magmatism and early Mesozoicthermal overprinting

The cores of zircons from JJ03, JJ05 and JLH03 and the rims ofzircons from JLH10 with relatively high Th/U values show REE pat-terns of magmatic origin (Hoskin and Ireland, 2000; Hoskin andSchaltegger, 2003). Thus we prefer the upper intercept ages of1861 ± 35 Ma, 1849 ± 30 Ma and 1877 ± 10 Ma represent the crys-tallization ages of the Jingju medium-coarse grained K-feldspargranite, Jingju medium-fine grained K-feldspar granite and Jin-luohou gneissic granodiorite, respectively. Meanwhile the upperintercept age of 1878 ± 28 Ma for the rims of zircons from JLH10indicates the forming age of Jinluohou garnet-bearing biotitegranite. The Paleoproterozoic magmatism in Southwest Zhejiangformed during a narrow range of 1.83–1.89 Ga (Li and Li, 2007;Wang et al., 2008; Liu et al., 2009; Yu et al., 2009; this study). There-fore, a strong Paleoproterozoic magmatism occurred in SouthwestZhejiang, corresponding to one of the episodic magmatism withpeak age at ca. 1.9 Ga worldwide (Ding et al., 2005; Kemp et al.,2006; Yu et al., 2006; Xu et al., 2007; Iizuka et al., 2010; Wang et al.,2010; Condie et al., 2011).

For the same reason as above, zircons from JJ07 exhibit charac-teristic of magmatic origin. But the rims of zircons from JLH03 with

relatively low Th/U values show complicated REE patterns fromthe cores, indicating that the intrusions have experienced a high-grade metamorphism or migmatization (Hoskin and Ireland, 2000;Rubatto, 2002; Hoskin and Schaltegger, 2003). In contrast, the rims

196 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

Table 7Nd-isotope compositions of representative samples from Jinluohou and Jingju granitic complexes.

Sample Sm (ppm) Nd (ppm) 147Sm/144Nd 143Nd/144Nd 2� εNd(t) TDM (Ga) T2DM (Ga)

Jinluohou gneissic granodioriteJLH03 13.50 75.80 0.107605 0.511315 2 −4.4 2.63 2.71JLH04 10.52 55.67 0.114201 0.511327 2 −5.7 2.78 2.82JLH06 12.52 67.63 0.111863 0.511346 9 −4.8 2.69 2.74

Jinluohou garnet-bearing biotite graniteJLH08 25.04 120.31 0.125769 0.511417 3 −6.7 2.99 2.90JLH09 8.08 40.17 0.121513 0.511355 1 −6.9 2.95 2.91JLH10 7.91 37.86 0.126255 0.511333 5 −8.5 3.15 3.04

Jingju medium-fine grained two-mica K-feldspar graniteJJ03 15.11 96.39 0.094703 0.511408 2 0.7 2.23 2.31

Jingju medium-coarse grained two-mica K-feldspar graniteJJ05 16.72 109.45 0.092270 0.511391 1 0.5 2.20 2.30

0.50.5

o0r

cm

Fd

Jingju porphyritic quartz monzoniteJJ06 14.06 73.02 0.116308

JJ07 12.20 71.69 0.102858

f zircons from JJ03 and JJ05 with higher Th/U values (average of.83 and 0.79, respectively) than the cores (average of 0.35 and 0.30,

espectively) show REE patterns of metamorphic characteristics.

Generally, Th/U ratios have become a commonly employedriterion for distinguishing zircon formation in magmatic, meta-orphic and hydrothermal environments, and magmatic zircons

1.85Ga

3.4Ga

DM

CHUR

150010005000

3.8Ga

0

-10

-20

-40

10

20

-30

εf

H)

( t

NC

Age(

1000500 15000

0.280

0.281

0.282

0.283DM

CHUR

77

16

71

ifH

/fH

1.85Ga

3.4Ga3.8Ga

NC

Bad

Pale

Pale

ECathaysiabasement

ECathaysiabasement

ig. 9. Hf-isotope compositions of representative zircons from Jingluohou and Jingju granata of Badu complexes, Paleoproterozoic A-type and S-type granites are after Xiang et a

11793 1 −14.2 2.12 2.1511726 1 −15.1 1.95 2.23

often show much higher Th/U ratios. A Th/U value of less than0.1 has been widely cited as a discriminant of metamorphic zircon

(Rubatto, 2002). It is noted that the rims in the zircon from the sam-ples JJ03 and JJ05 have higher Th/U ratios than the cores. In fact, therims of zircons from JLH03 have lower Th/U ratios (average of 0.25)than the cores (average of 0.49), but still greater than 0.1. Harley

40003500300025002000

Lu/Hf=0.015

Ma)

25002000 35003000 4000

Lu/Hf=0.015

ucomplex

oproterozoicA-typegranites

oproterozoicS-typegranites

JLH03

JLH10

JJ03

JJ05

JJ07

itic complexes (the area of Eastern Cathaysia basement is after Xu et al., 2007; thel., 2008; Yu et al., 2009, in press).

Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207 197

Fig. 10. (a) The total alkali vs. silica (TAS) diagram (after Middlemost, 1994) used for the classification of the Jinluohou and Jingju samples. (b) Chemical compositions oft OT/(FeF er TurP jiang a

eipH

Ft

he Jingluohou and Jingju granitic complexes in terms of alumina saturation. (c) Ferost et al., 2001; Frost and Frost, 2011). (d) K2O vs. Na2O variation diagram (aftaleoproterozoic orthometamorphic and metasedimentary rocks in Southwest Zhe

t al. (2007) suggested that high Th/U ratios could be recorded

n recrystallized zircon or zircon grown during high-T metamor-hism, so the use of Th/U ratios should be treated with caution.ence, extreme variation of REE patterns and equal or higher

Calc-alka

Potassic alkaline

Tholeii

High-K calc-Shoshonitic

8

6

4

2

18

16

14

12

10

Al O32

SiO2

10

8

6

4

2

045 50 55 60 65 70 75 80 85

CaO

0

0.1

0.2

0.3

0.4

SiO

45 50 55 60 65

ig. 11. Harker diagram of major-element compositions of the Jinluohou and Jingju samhe division between potassic alkaline and shoshonitic suites (after Calanchi et al., 2002).

OT + MgO) vs. SiO2 diagram for the Jingluohou and Jingju granitic complexes (afterner et al., 1996). Data source for S- and A-type granites together with Cathaysiare given in Appendix Table.

176 177

initial Hf/ Hf ratios between rims and cores of zircons fromJJ03, JJ05 and JLH03 (Figs. 6 and 9), suggest that these rims arethe recrystallization or overgrowth of protogenesis zircons. But theHf model ages of the rims have the same range with the cores,

line

tic

alkaline

K O2 4

3

2

1

Na O2

2

70 75 80 85

P O52

0

4

8

12

16

20

24

SiO2

45 50 55 60 65 70 75 80 85

TFMM

ples, SiO2 vs. K2O (after Peccerillo and Taylor, 1976), where dotted line represents Symbols and data sources are the same as in Fig. 10.

198 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

1

0.1

10

100

1000

1000

LaKNb TaTh UBaRb Nd PSrPbCe HfZrSm Yb Lu YTbTiEu

Sa

mp

le/C

ho

nd

rite

Sa

mp

le/p

rim

itiv

e-m

an

tle

1

10

100

1000

1000

1

10

100

1000

La Ce NdPr Sm Eu Gd LuYbTmErHoDyTb

10

100

1000

a

b

c

d

F ltiple

a nough

sm1mezoegmsrTgeii

Fcε(

ig. 12. Chondrite-normalized REE patterns and Primitive mantle-normalized mure from Taylor and McLennan (1985). The primitive mantle values are from McDo

uggesting that later metamorphism would not involve any otheraterials (Fig. 9). In fact, octahedral coordination U4+ (radius of

.00 A), with smaller ion radius than Th4+ (radius of 1.05 A) andore similar to the smaller ion Zr4+ (radius of 0.84 A), is prefer-

ntially entering into the lattice of zircon. Thus, early crystallizedircons may have lower Th/U ratios than later ones, and the coref the zircons may show lower Th/U ratios than the rim. Möllert al. (2003) showed that Th/U ratios in recrystallized and newlyrown metamorphic zircon were unchanged in comparison to theiragmatic zircon precursors (and never less than 0.1), with some

ignificantly higher. From the above discussion, the protogeneticims of zircons from the samples JJ03 and JJ05 may show higherh/U ratios than cores, and secondary recrystallization of the proto-enetic rim or newly grown metamorphic zircon may keep or even

levate the Th/U ratios. Previously studies reported many lowerntercept ages of 226–243 Ma (Xiang et al., 2008; Yu et al., 2009,n press) and mean metamorphic zircon age of 209–248 Ma (Li and

ig. 13. (a) Whole-rock Nd-isotope compositions of Jingluohou and Jingju granitic complomplex is after Chen and Jahn, 1998; Yu et al., in press; the area of Paleoproterozoic A-tHf(t) diagram for the Jingluohou and Jingju granitic complexes. The trend of the terrestDM) from Blichert-Toft and Albarède (1997), a suggested field for the bulk cratonic (SCLM

trace element diagrams of the Jinluohou and Jingju samples. The chondrite values and Sun (1995). Symbols and data sources are the same as in Fig. 10.

Li, 2007; Wang et al., 2008; Xiang et al., 2008; Yu et al., 2009), butthe definite age of the early Mesozoic metamorphic event is stillnot clear. The zircons U–Pb dating results, and weighted mean agefor Jingju porphyritic quartz monzonite of 226.2 ± 1.4 Ma, whichin conformity with the ages of thermal event recorded in zirconrims from JJ03, JJ05 and JLH03 (with lower intercept at 224 ± 63 Ma,231.4 ± 6.8 Ma and 224 ± 19 Ma, respectively), may constrain theearly Mesozoic thermal overprinting event during 224–231 Ma.

5.2. Hf–Nd decoupling of the Jingju K-feldspar granite

It has been well recognized that Lu–Hf and Sm–Nd isotope sys-tems behave analogously during most magmatic processes and that

the Hf and Nd isotopic compositions should have positive correla-tion in most igneous rocks (Vervoort et al., 1999). However, theSm–Nd isotopic systems can be disturbed during fluid-rock inter-action in the later hydrothermal event (e.g., Pronost et al., 2008;

exes (the area of Cathaysia basement is after Chen and Jahn, 1998; the area of Baduype granites and Paleoproterozoic S-type are after Yu et al., in press). (b) εNd(t) vs.rial array is from Vervoort et al. (1999). Bulk Silicate Earth (BSE), Depleted Mantle

) from Griffin et al. (2000). Symbols are the same as in Fig. 10.

arch 216– 219 (2012) 177– 207 199

LpviKaJts

5M

5

aFKdiitiHaZthtbpaTlmca1o≥wecw

g(2rzfsgtBepTm2Soma

t

Y. Xia et al. / Precambrian Rese

uais et al., 2009). Jingju K-feldspar granite displays Hf–Nd decou-ling (Fig. 13b) and exhibits obviously higher εNd(t) and lower T2DMalues than other Paleoproterozoic granites in this region, imply-ng that a fluid or melt with higher εNd(t) might interact with Jingju-feldspar granite and reset its Sm–Nd isotopic equilibrium. After

simple conversion (Fig. 13a), the Sm–Nd isotopic compositions ofingju porphyritic quartz monzonite are exactly matched. Hence,he early Mesozoic magmatism might disturb the Sm–Nd isotopicystem of Jingju K-feldspar granite.

.3. The geneses of the Paleoproterozoic granites and earlyesozoic monzonite

.3.1. Paleoproterozoic S-type granitesThe Jinluohou garnet-bearing biotite granite is strongly per-

luminous with A/CNK > 1.1 (Fig. 10b), and has relatively loweOT/[FeOT + MgO], low contents of P2O5 and high contents of2O (Fig. 11). It is plotted in the field of S-type granite in ACFiagram (Fig. 14a; White and Chappell, 1977). Petrographically,

t contains a large amount of biotites and garnets with minornherited zircons (Fig. 5). The rims of zircons from JLH10 show flat-er HREE contents than the cores, possibly as a result of growthn the equilibrium magma with garnet (Schaltegger et al., 1999;oskin and Schaltegger, 2003), providing further evidence for per-luminous granitic magma. All these s are similar to Southwesthejiang Paleoproterozoic S-type granites, and belong to the S-ype granites of Chappell and White (1974). Barbarin (1996, 1999)ad further distinguished two main types of peraluminous grani-oids (S-type granite), i.e. muscovite-bearing granitoids (MPG) andiotite rich, cordierite-bearing granitoids (CPG). MPG is relativelyoor in biotite and contains large amount of primary muscovitesnd CPG may contain cordierites and enriched in aluminous biotite.he essential petrogenetic difference between the MPG and CPGargely is that CPG have much lower water fugacity and higher mag-

atic temperatures. The Jinluohou garnet-bearing biotite graniteontains abundant garnets and no primary muscovites (Fig. 3j–l)nd has higher Zr saturation temperature (Watson and Harrison,983) up to 809 ◦C (Table 6), characteristic of CPG. The presencef garnet and absence of cordierite suggest the generation depths25 km deep (Green, 1976). Such relatively high pressure, lowerater fugacity and higher temperature formation conditions can

xplain the relatively high Ga/Al ratios and HFSE (Zr, Nb, Ce, Y)oncentration of Jinluohou garnet-bearing biotite granite prettyell.

Inherited zircons from S-type granites provide exceptionallyood insight into the isotopic heterogeneity of their sourcesVillaros et al., 2012). The inherited zircon cores (ranging from088 to 2929 Ma) in S-type Jinluohou garnet-bearing biotite graniteequire a mixed source rock including Archean and Paleoprotero-oic sediments. As per Chappell (1999), S-type granite is derivedrom partial melting of supracrustal rocks that have undergoneome extent of weathering. Therefore, the source of the S-typeranites is mainly composed of sedimentary rocks, and their detri-us originated from Archean to Paleoproterozoic crust. In fact, theadu complex mainly consists of diverse sedimentary rocks (Hut al., 1991), and the Nd model ages (2.70–3.04 Ga; Yu et al., inress and this study) and Hf model ages (2.37–3.60 Ga for TNC or2NC; Fig. 9) of zircons in S-type granites have overlap with their Ndodel ages of 2.72–2.81 Ga (Hu et al., 1991) and Hf model ages of

.40–4.10 Ga (Yu et al., in press). Hence the inherited zircon cores in-type Jinluohou garnet-bearing biotite granite with REE patternsf magmatic origin may be d from the Badu complex, implying the

ainly protoliths of S-type Jinluohou garnet-bearing biotite granite

re the sedimentary rocks of Badu complex.In source discrimination diagrams based on the major and

race elements, both Paleoproterozoic S- and A-type granites in

Fig. 14. Various chemical discrimination diagrams for Jingluohou and Jingju graniticcomplexes. (a) After White and Chappell (1977). (b) and (c) After Whalen et al.(1987). Symbols and data sources are the same as in Fig. 10.

Southwest Zhejiang show a mixed source including metapeliticrocks, metagreywackes and metabasaltic rocks or amphibolites(Fig. 15a and b), but the relative proportions are different. S-type granites have similar major and trace element contentsto Cathaysia Paleoproterozoic metasedimentary rocks and felsicorthometamorphic rocks (Figs. 11 and 12a, c), and their Hf–Ndisotopic compositions indicate that Paleoproterozoic S-type gran-

ites in Southwest Zhejiang may be petrogenetically linked tothe metamorphic rocks of Badu complex through partial melt-ing. Nevertheless, the mechanism to induce partial melting ofmetasedimentary rocks is often debatable. Barbarin (1996, 1999)

200 Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207

basalt

pelitederivedmelt

50%

20%

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90%

60%

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ig. 15. Source discrimination diagrams for Jingluohou and Jingju granitic complex1998). Symbols and data sources are the same as in Fig. 10.

ave demonstrated that the CPG-type granitoids are generatedhere mantle-derived magma is injected into, or has underplated.

hus, these S-type granite are formed by partial melting of Pale-proterozoic to Archean basement in the lower crust induced bynderplating or injection of hot mantle-derived magmas. The Jin-

uohou garnet-bearing biotite granite, together with some otheraleoproterozoic S-type granites, exhibits relatively close relation-hip with basalts or amphibolites (Fig. 15a–d). Since the protolithf S-type granite is mainly pelitic or psammitic rock (Patino Douce,999; Sylvester, 1998), one needs to be careful to conclude therigin of S-type granite by dehydration melting from amphibo-ites (Fig. 15a and b). In fact, the relatively high CaO/Na2O ratios>0.3) and low SiO2 contents (part of samples <71 wt.%) implyhat the Jinluohou garnet-bearing biotite granite and other Pale-proterozoic S-type granites could be produced from psammiticources or pelite-derived melts that interacted with mafic magmasSylvester, 1998). However, Fig. 15d indicates that the Jinluohouarnet-bearing biotite granite and some other Paleoproterozoic S-ype granites in this region have lower Rb/Ba and Rb/Sr ratios thansammite-derived melts and Fig. 15c and d suggests that part ofantle-derived magma may interfuse into the host magma of these

-type granite, which can be easily accommodated because of thepatial affinity between S-type Jinluohou garnet-bearing biotiteranite and A-type Jinluohou gneissic granodiorite. Actually, a lot ofesearchers (Patino Douce, 1999; Sylvester, 1998) believed that the

nteractions between the continental crust and underplating mafic

agmas are not only limited to mere heat transfer but also chemi-al interactions take place in many instances. From whole rock Ndnd zircon Hf isotopes (Figs. 9 and 13a), the injected mantle-derived

After Altherr et al. (2000). (b) After Patino Douce (1999). (c) and (d) After Sylvester

magmas probably produced by partial melting of the old, radiogenicNd and Hf isotope enriched continental lithosphere mantle.

5.3.2. Paleoproterozoic A-type granitesJingju K-feldspar granite and Jinluohou gneissic granodiorite

have high P2O5 that decreases with increasing SiO2 or extent offractionation (i.e., apatite removal; Fig. 11), which is an importantcriterion to distinguish between I-type or A-type and S-type gran-ites for highly evolved samples (Chappell, 1999). Petrographically,these granitic rocks contain interstitial mafic minerals such as chlo-ritic biotites both in Jingju K-feldspar granite and Jinluohou gneissicgranodiorite and amphiboles only in Jinluohou gneissic granodior-ite (Fig. 3a, d, g and h). Veblen and Ferry (1983) suggested that thechemical changes for the transformation from biotite to chloritewere the following: large introductions of H2O and H+; relativelyminor introductions of Mg and Fe; and major losses of K and Si. Infact, the major element composition of granitic chlorite is stronglyinfluenced by the composition of the parent biotite (Dodge, 1973),therefore, the chlorites have similar FeOT/(FeOT + MgO) ratios tothose of their host biotites (Tulloch, 1979). According to the revisionof mica classification (Rieder et al., 1998), all the chloritic biotitesin Jingju K-feldspar granite and Jinluohou gneissic granodiorite areclose to the Fe-rich siderophyllite-annite end member (Fig. 4). Geo-chemically, they are ferroan granites (Fig. 10c) and enriched in REE(except for Eu, Fig. 12b), depleted in Ba, P and Sr (Fig. 12d), and

show high Ga/Al and FeOT/(FeOT + MgO) ratios and HFSE (Zr, Nb,Ce, Y) (Fig. 14b and c). It should be noted, however, that these dis-crimination diagrams are ineffective for highly evolved granites.Both A-type and highly evolved I-type granite can possess higher

Y. Xia et al. / Precambrian Research 216– 219 (2012) 177– 207 201

by, 19

v2me1Th1fgnaAtoadAtgfKfohc(o

Fe

Fig. 16. Subtype classification of A-type granites (after E

alues of Ga/Al ratios and HFSE contents (Eby, 1992; King et al.,001). Nevertheless, temperatures calculated from the geother-ometer based on the Ti/Fe2+ value of biotite (up to 837 ◦C and

ven higher for the effect of choritization; Table 2; Luhr et al.,984) and the Zr saturation thermometer (840–854 ◦C, >830 ◦C;able 6; Watson and Harrison, 1983) indicate that they have muchigher initial temperatures than I-type granite (Clemens et al.,986; King et al., 1997, 2001). High temperature also can accountor the absence of inherited zircons. Differ from peralkaline A-typeranites, the Jingju K-feldspar granite and Jinluohou gneissic gra-odiorite can reach to strongly peraluminous (A/CNK = 0.97–1.26)nd contain Fe rich annites (Fig. 4), indicating they are aluminous-type granites (Collins et al., 1982; King et al., 1997). Generally,

he albite-orthoclase solid solutions or intergrowths commonlyccur in A-type granites, and micrographic intergrowths of quartznd alkali feldspars and the perthites would be petrographic evi-ence for high temperature and low pressure crystallization of-type granites. But only rare perthites can be observed and the

exture of micrographic intergrowths is absent in these A-typeranites. However, Bonin (2007) mentioned that subsolvus typeeldspar (Tuttle and Bowen, 1958) may contain discrete crystals of-feldspar and plagioclase, which exactly match the petrographic

eature of Jingju K-feldspar granite and Jinluohou gneissic gran-diorite, suggesting that these A-type granites may crystallize at

igh pressure and deeper depths (Martin and Bonin, 1976). Highontents of Rb and high Rb/Nb and Y/Nb ratios of these granitesFig. 16) further suggest that Jinluohou gneissic granodiorite andther Southwest Zhejiang Paleoproterozoic A-type granites (e.g.

ig. 17. Tectonic setting discrimination diagrams: Rb/Zr vs. SiO2 discrimination diagramt al. (1984) and Pearce (1996). Symbols and data sources are the same as in Fig. 10.

92). Symbols and data sources are the same as in Fig. 10.

Liu et al., 2009; Yu et al., 2009) belong to the A2 subgroup of Eby(1992). However, as per Eby (1992), these A1 and A2 discriminantdiagrams should only be used for granitoids that plot both in thewithin-plate granite field of Pearce et al. (1984). Therefore, suchdiscriminant diagrams are not suitable to Jingju K-feldspar granite,which plot in syn-collisional granite field (Fig. 17). It is that JingjuK-feldspar granite must form in the same tectonic setting of othercoeval A-type granites.

Petrogenetic models for A-type magma are not unanimous, andtheir source may include: residual source after the extraction of I-type magma (Clemens et al., 1986; Collins et al., 1982); a tonalitic togranodioritic metaigneous source (Anderson, 1983; Whalen et al.,1987; Creaser et al., 1991); extensive fractional crystallization frommantle-derived basaltic magma (Turner et al., 1992; Frost andFrost, 1997; Frost et al., 1999); further fractional crystallization orcrustal contamination of syenitic melt (Dickin, 1994; Charoy andRaimbault, 1994; Litvinovsky et al., 2000, 2002). But Anderson andThomas (1985) and Whalen et al. (1987) found that melting of pre-viously dehydrated metasedimentary source rocks also can formA-type granite, which may be the most suitable model to explaintheir genetic affinity with S-type granites in the PaleoproterozoicS- and A-type granites association.

The typical Paleoproterozoic A-type granites in Southwest Zhe-jiang including Jinluohou gneissic granodiorite plot between the

fields of Cathaysia Paleoproterozoic metasedimentary rocks or fel-sic orthometamorphic rocks and amphibolites in Fig. 11, and exhibitrelatively closer to the basalt on mixing curve in Fig. 15c and d.It is noted that the amphibolites have chemical compositions of

is after Harris et al. (1986); Rb vs. (Y + Nb) discrimination diagram is after Pearce

2 arch 2

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02 Y. Xia et al. / Precambrian Rese

ithin-plate basalts or mid-ocean ridge basalts (MORB) (Li et al.,000) which represent the composition of coeval mantle-derivedagmas with those S- and A-type granites. It seems that A-type

ranites show genetic affinity with mantle-derived magmas. How-ver, granites cannot be directly derived from the mantle (Wyllie,984), and the most feasible petrogenetic model for these A-ype granites should be the majority crustal source mixed withven relatively higher proportions of mantle-derived melts. Allhe Paleoproterozoic A-type granites in Southwest Zhejiang haveimilar REE and trace elements patterns to Cathaysia Paleoprotero-oic metasedimentary rocks and felsic orthometamorphic rocksFig. 12b and d) and comparable Hf and Nd isotopic compositionsith the Badu complex (Figs. 9 and 13a). But their εHf(t) values

ary from −22.3 to +7.5 and broad range of Hf model ages (TNCr T2NC) from 1.83 Ga to 3.87 Ga (Fig. 9), indicating that they alsonvolved the input of juvenile material and reveal the existence ofrust–mantle interaction, as argued by Xu et al. (2007). Nonethe-ess, the aluminous A-type Jingju K-feldspar granite plots in the fieldf partial melt from metapelitic sources (Fig. 15a and b), and plotsn the positions more close to the pelite-derived melt than other A-ype granites or even S-type granites. It is because that these twoluminous A-type granites are partial melts from clay-rich sourcesFig. 15d). The mantle-derived melt required in their petrogenesiss most likely of asthenospheric origin as further manifested by zir-on εHf(t) > 0 afforded by some samples from Jinluohou and Jingjuranitic complexes (Fig. 9).

.3.3. Early Mesozoic monzoniteThe εHf(t) of Jingju porphyritic quartz monzonite are plotted in

he evolution domain of Paleoproterozoic S- or A-type granites, andnitial 176Hf/177Hf ratios and Hf model ages have identical range

ith Paleoproterozoic S- or A-type granites (Fig. 9). However, theower SiO2 contents and higher mafic compositions of the Jingjuorphyritic quartz monzonite preclude their genesis by the directemelting of the S- or A-type granites or the same protoliths of those- or A-type granites. Thus, it is inferred that Jingju porphyriticuartz monzonite may be derived from Paleoproterozoic crustalaterials mixed with juvenile basic or intermediate rocks (Fig. 15c

nd d). And the Nd-isotope compositions indicate that the Meso-oic reworking not only recycled of old basement but also involveduvenile material (Fig. 13a).

.4. Tectonic setting for the Paleoproterozoic magmatism andarly Mesozoic thermal event

.4.1. Tectonic setting for the Paleoproterozoic magmatismThe Paleoproterozoic S- and A-type granites association in

outhwest Zhejiang can provide important information aboutegional tectonic activities and crustal evolution. Previous stud-es suggest that S-type granites generally form in compressionalnvironment caused by collision (Pearce et al., 1984; Harris et al.,986), but recently increasing number of studies notice that S-typeranites may also occur in extensional environment. Such exten-ional environment may stem from postcollisional stress relaxationSearle et al., 1997; Sylvester, 1998; Healy et al., 2004) or even man-le upwelling or underplating (Barbarin, 1996, 1999). The A-typeranite suite is conventionally considered to form in anorogenicnd rifting environments (Loiselle and Wones, 1979). However,halen et al. (1987) and Bonin (2007) argue that A-type granite

an be connected to various tectonic environments, so long as suchnvironments can produce favorable conditions (high temperaturend low-water) for A-type granite formation, including oceanic

slands, continental rift environments, attenuated crust, intra-ontinental ring complexes, postorogenic environments involvingrc-arc or arc-continent collisions, transcurrent fault, or even sub-uction environments (Eby, 1992; Whalen et al., 1987; Bonin,

16– 219 (2012) 177– 207

2007). The basic rule is that A-type granite may be produced when-ever or wherever extensional setting or the extension mechanismoccurs.

In various tectonic setting discrimination diagrams (Harris et al.,1986; Pearce et al., 1984; Pearce, 1996), the Paleoproterozoic S-type granites in Southwest Zhejiang plot in the post-collisionalfield or straddle the boundary between the post-collisional, vol-canic arc granites and syn-collisional fields. The PaleoproterozoicA-type granites in Southwest Zhejiang plot in the within-plate,volcanic arc granites or post-collisional field (Fig. 17). However,these tectonic-setting discrimination diagrams have their own lim-itations, as pointed out by Pearce et al. (1984) and Förster et al.(1997), granites composition essentially depends on the nature ofthe source rocks, and is controlled only in the simplest cases bythe tectonic setting. So it is necessary to make concrete analysis forspecific conditions.

The Paleoproterozoic S-type and A-type granites in SouthwestZhejiang exhibit typical trace elements features of volcanic arcgranites (Figs. 12a, d and 17). However, the absence of coevalandesites and I-type granites does not support the volcanic arc set-ting. In fact, the arc-related and geochemical features of the S-typeand A-type granites, as shown in Figs. 12 and 17, may be inheritedfrom their source (arc-continent collision) (Yu et al., 2009, in press),less extent of fractionation or their original magma may have beengenerated by decompression melting with fluid addition (Pearce,1996; Förster et al., 1997).

Yu et al. (2009, in press) considered the Paleoproterozoic mag-matism and high-grade metamorphism as the record of orogeny ineastern Cathaysia Block, and the Southwest Zhejiang probably is aremnant of Columbia. According to this model, the S-type granitesare formed in the syn- to early post-collisional orogenic stage, andthe A-type granites probably form in a post-orogenic setting (Yuet al., 2009). Although some granites plot in syn-collisional fields,it does not necessarily mean such granites have to form in com-pressional environment. Förster et al. (1997) have shown exampleswhere continental arc magmatism involved pelitic source rocksto produce granites with a syn-collisional granites signature. S-type Jinluohou garnet-bearing biotite granite, characteristic of CPGsubgroup, can be linked to extensional environment as a result ofmantle upwelling or basaltic underplating (Barbarin, 1996, 1999).So at least parts of or even all the S-type granites in SouthwestZhejiang are not form in extensional tectonic settings.

Eby (1992) subdivided the A-type suite into subgroups A1 andA2, and the Paleoproterozoic A-type granites assembly are mainlyof A2 subgroup (Fig. 16) which are predominantly regarded as for-mation in post-collisional tectonic settings. Liégeois et al. (1998)argued that abundant high-K calc-alkaline to shoshonitic magma-tism appears to be post-collisional in the final stages of orogeny.The Southwest Zhejiang Paleoproterozoic S- and A-type granitesplot in the shoshonitic and high-K calc-alkaline fields (Fig. 10d),implying that these granites are dominated by post-collisionalenvironments. Nevertheless, some Paleoproterozoic meta-maficrocks (amphibolites) have been found in the northwestern Fujianand southeastern Zhejiang (1766–1781 Ma; Li, 1997; Li et al., 2010),indicating this area experienced intraplate rifting leading to maficmagmatism at 1.76–1.80 Ga (Li, 1997; Wan et al., 2007; Li et al.,2010). Yu et al. (2009) argued that such case suggests changes inthe geodynamic setting of magma generation with time, that is theregion went through a complete Paleoproterozoic tectonic cyclefrom syn-orogenic to post-orogenic, and then to an anorogenic (rift-ing) setting. However, Xiang et al. (2008) advanced the beginningof the intraplate rifting and mafic magmatism at 1.85 Ga. Although

the age of 1.85 Ga may be an overestimate because of probable dis-turbance by inherited zircons which usually occur in mafic volcanicrocks, it suggests beginning of intraplate rifting at the time whenS- and A-type granites formed. In addition, the major and trace

arch 2

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lements patterns of S- and A-type granites association indicate theontribution of mantle-derived magma caused by intraplate rifting.bviously, the post-collisional tectonic settings can hardly explain

uch geochemical features. Furthermore, A2 subgroup granitoidsctually can occur in a variety of tectonic settings, including post-ollisional or pure anorogenic environments (Eby, 1992).

Considering the ages and geochemical features of the Paleopro-erozoic S- and A-type granites association in Southwest Zhejiang,e propose a new model of anorogenic setting to explain the mag-atic process of S- and A-type granites and the regional crustal

volution. At ca. 1.85–1.89 Ga, Southwest Zhejiang witnessed theeginning of intraplate rifting, and the asthenosphere upwellingnd mantle-derived magmas underplating occurred simultane-usly. The lower crust underwent anatexis and strong crust–mantlenteraction with the temperature rising. At the less thinned crustear the rift, the extension is less extensive, the temperature is rel-tively low, and the upwelling of asthenosphere triggered partialelting of the preexistent Paleoproterozoic to Archean continental

ithosphere mantle. Therefore, lithosphere mantle-derived magmanderplating and metasedimentary rocks in lower crust dominatedhe formation of S-type granites. If the asthenosphere mantle-erived magma is abundant and the temperature is relatively high,he mixing of metasedimentary rocks, refractory metaigneous com-onents and mantle-derived magma contributed major-elementomponents and Hf-isotope compositions of the A-type granites.he protoliths of Badu complex, formed prior to Paleoproterozoicr probably Archean (see discussion below), had been recycled oreworked with the involvement of juvenile material and experi-nced high grade metamorphism. The volume of juvenile crustight not be significant until ca. 1.80–1.85 Ga when intraplate

ifting developed into a proto-oceanic basin and abundant basaltagma intruded (Li, 1997). There is still a lack of reliable age for

he amphibolites to constrain the commencement of the intraplateifting.

To sum up, questions remain to be answered regarding whetherost-collisional or intraplate rifting tectonic settings dominate theenesis of the Paleoproterozoic S- and A-type granites associationn Southwest Zhejiang, “Paleoproterozoic orogen” (1.83–1.89 Ga)nd whether the Southwest Zhejiang is a remnant of the assemblyf the supercontinent Columbia (Nuna) (Zhao et al., 2002; Rogersnd Santosh, 2002). Based on present information, we prefer thentraplate rifting model as a feasible model for the Paleoprotero-oic crustal growth and reworking with concomitant magmatismn Southwest Zhejiang. The Paleoproterozoic crustal growth eventlso provides another evidence to support the episodic growthodel in Cathaysia block, corresponding to the 1.9 Ga crustal

rowth event worldwide (Kemp et al., 2006; Xu et al., 2007; Iizukat al., 2010; Wang et al., 2010; Condie et al., 2011).

.4.2. Tectonic setting for the early Mesozoic thermal eventA significant tectonic activation of Southwest Zhejiang area

ccurred at Permo-Triassic and is represented by medium- to high-rade metamorphism and the coeval magmatism at 252–226 Ma.s a result, the Badu complex and S- and A-type granites underwentigh-grade metamorphism probably having reached granulite

acies (Li and Li, 2007; Wang et al., 2008; Xiang et al., 2008; Yut al., 2009, in press). The metamorphism not only led to Pb-loss inaleoproterozoic zircons and older (Archean) inherited cores, butlso caused overgrowth or recrystallization of rims on earlier zir-ons (Fig. 5). The weighted mean age of Jingju porphyritic quartzonzonite (226.2 ± 1.4 Ma) and the lower intercept age of Jinluo-

ou gneissic granodiorite, Jingju K-feldspar granite (224–231 Ma)

onstrain the early Mesozoic metamorphic age of Badu complexnd syntectonic granitoids during 224–231 Ma.

The early Mesozoic tectonic setting within the South China inte-ior is still a subject for debate. Distinct viewpoints on the tectonic

16– 219 (2012) 177– 207 203

background include the collision between Indochina Block andSouth China Block (Wang et al., 2002, 2007; Zhou et al., 2006; Dinget al., 2006; Chen et al., 2007), the late Permian-Triassic intracon-tinental collision (Hsü et al., 1988, 1990) or the subduction of thepaleo-Pacific plate (Guo et al., 1983; Ren et al., 1990; Wang et al.,2005; Li et al., 2007; Li and Li, 2007; Ferrari et al., 2008). Recently,models invoking the subduction of the paleo-Pacific plate havebecome widely accepted by many scholars (Xiang et al., 2008; Sunet al., 2011).

A series of A-type granites, syenites (e.g. Gaoxi aluminous A-typeGranites; Wengshan aluminous A-type granites; Tieshan alkalinesyenites; Chen et al., 1997; Wang et al., 2005; He et al., 2009;Sun et al., 2011) and Jingju porphyritic quartz monzonite dis-tributed in the coastal region of the SCB are NE-trending (Zhouet al., 2006), and show enrichment in large-ion lithophile elementsand LREE and depletion in HFSE (Fig. 12a and c; Chen et al., 1997;Wang et al., 2005, 2007; Sun et al., 2011), indicating that they mayform in subduction related settings. These plutons are on intimateterms with mantle-derived magma, and may be fractionated frombasaltic magma directly, implying that the Early Mesozoic magma-tism and metamorphism recorded another episodic crustal growthand reworking event.

5.5. Episodic crustal accretion and reworking on the Archeanbasement (?) in Cathaysia block

The Cathaysia block overprinted at least two episodes (Paleo-proterozoic and early Mesozoic) of magmatism, according to thisstudy. Generation of granitic magmas is always associated in spaceand time with growth, rather than just recycling, of the continentalcrust (Patino Douce, 1999). The Hf-isotope compositions of zirconsand whole-rock Nd-isotope compositions of Jinluohou and Jingjugranitic complexes reveal the Paleoproterozoic and early Meso-zoic crust–mantle interactions in this region are not only crustalreworking but also accretion. These large-scale crustal accretionand reworking events are corresponding with the peak ages ofinherited zircons (Ding et al., 2005; Yu et al., 2006; Xu et al., 2007;Wang et al., 2010), in line with the episodic crustal growth model.But it is hard to imagine that the Paleoproterozoic and early Meso-zoic crust–mantle interactions produce such large Cathaysia block.In contrast, Sm–Nd isotope studies suggested that 35–60% of thepresent crustal mass had formed in the Archean (Patchett andArndt, 1986; McCulloch, 1987; Jacobsen, 1998; DePaolo et al., 1991)and the average growth rate of continental crust had decreasedsince the Archean (Belousova et al., 2010; Hawkesworth et al.,2010). Based on the study of Badu complex, Yu et al. (in press)suggested that the inherited cores of zircon grains from the Baducomplex metamorphic rocks are of magmatic origin, predomi-nantly formed at ca. 2.5 Ga. The unimodal age distribution (ca.2.5 Ga) of detrital zircons and the positive εHf(t) of most Neoarcheanzircons suggest that the detritus of these sedimentary protoliths ofthe Badu complex came from a proximal volcanic arc, and that theywere deposited in an arc basin synchronously with ca. 2.5 Ga vol-canism. According to the global episodic crust growth model at 2.7,1.9, and 1.8 Ga, there should have a crust aged at 2.5–2.7 Ga for theeroding source for the sedimentary protoliths of the Paleoprotero-zoic granites. Is the Cathaysia block just an old Archean basementoverprinted by episodic crustal accretion and reworking?

Fu et al. (1991) reported a Sm–Nd isochron age of 2682 ± 148 Mafor the amphibolites from Tianjinping, NW Fujian. It has been con-sidered as a pierce of convincing evidence for the existence of lateArchean crust in the Cathaysia Block. However, the reported Sm–Nd

regression line is most likely an errorchron rather than an isochron,and the age 2.7 Ga for the amphiholite has been questioned and con-sidered to be geologically meaningless (Li, 1996). Although lackingdirect evidence of Archean rocks, numerous Archean U–Pb ages of

2 arch 2

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6

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nherited zircons and Hf isotopic model ages (Xu et al., 2007; Yut al., 2009; Liu et al., 2009; this study) or whole-rock Nd modelges (Chen and Jahn, 1998; Shen et al., 2000; this study) as dis-ussed above shed light on for exploring the Archean crust in thisegion.

Most of the inherited zircon cores in S-type Jinluohou garnet-earing biotite granite distribute along a well-defined discordiaith an upper intercept age of 2681 ± 200 Ma. In combination with

he Hf model ages (TNC or T2NC) ranging from 2.37 Ga to 3.60 GaFig. 9) and Nd model ages ranging from 2.90 Ga to 3.04 Ga (Table 7),he available data imply that the source of this S-type granite maye the Neoarchean sediments. As above mentioned, S-type gran-

te is derived from partial melting of supracrustal rocks that havendergone some extent of weathering (Chappell, 1999). Therefore,here must have pre-existing crust at least before Neoarchean. Howld is the Cathaysia Block? All the zircon cores derived from A-ype granites in Jinluohou and Jingju granitic complexes show Hf

odel ages (TNC or T2NC) clustering at a range of 2.50–3.00 Ga (Fig. 9)nd Nd model ages of Jinluohou gneissic granodiorite ranging from.71 Ga to 2.82 Ga (Table 7). The model ages suggest that the A-ype granites also originate from Neoarchean crustal material. Thef model ages (TNC or T2NC) ranging from 1.83 Ga to 3.87 Ga (Fig. 9)nd Nd model ages ranging from 2.71 Ga to 3.04 Ga (Table 7) of thealeoproterozoic S- and A-type granites association in this studyuggest that the Cathaysia Block even can be Paleoarchean time.

If the Archean crust does exist, then where are the Archeanocks? In fact, only 14% Archean crust preserved (Goodwin, 1991),ar less than the 35–60% exposed by Sm–Nd isotope studies men-ioned above. Considering the Cathaysia Block has suffered multipleectonic activities in the long geological history, the Archean rocksrobably locate in the unexposed deep crust, or they may have beenecycled or reworked during the extensive multiple tectothermalvents since Paleoproterozoic (Xu et al., 2007).

. Conclusions

1) The Jinluohou granitic complex is composed of gneissic gra-nodiorite and garnet-bearing biotite granite which intrudedat ca. 1877 Ma. The Jingju granitic complex is an assemblageof porphyritic quartz monzonite, medium-coarse grained K-feldspar granite and medium-fine grained K-feldspar granite.They formed at 1861 ± 35 Ma, 1849 ± 30 Ma and 226.2 ± 1.4 Ma,respectively. The U–Pb ages of Jinluohou and Jingju graniticcomplexes imply that a strong magmatism occurred in thePaleoproterozoic, and overprinted with early Mesozoic thermalevent in Southwest Zhejiang.

2) The petrographical studies and geochemical compositions indi-cate the Jinluohou garnet-bearing biotite granite show theS-type granite affinity. The Jingju medium-coarse grained K-feldspar granite, Jingju medium-fine grained K-feldspar graniteand Jinluohou gneissic granodiorite are A-type granites. Thegeochemical data, Nd isotopic and zircon Hf isotopic compo-sitions imply that the Paleoproterozoic S- and A-type granitesassociation involves multiple sources including the metasedi-mentary rocks, felsic orthometamorphic rocks of Badu complexand different proportions of mantle-derived melts. The Meso-zoic Jingju porphyritic quartz monzonite also involves the inputof juvenile material.

3) The Paleoproterozoic S- and A-type granites association revealsthe existence of crust–mantle interaction, suggesting that theyformed under intraplate extensional geodynamic setting. Judg-

ing from existing information, this geodynamic setting maybe caused by intraplate rifting tectonic settings. The Paleopro-terozoic magmatism is an important event of episodic crustalgrowth and reworking in Southwest Zhejiang. Early Mesozoic

16– 219 (2012) 177– 207

magmatism and metamorphism caused by subduction of thepaleo-Pacific plate imply that another episodic crustal growthand reworking event took place in this region.

(4) U–Pb ages of inherited zircons, Hf-isotope compositions ofzircons and whole-rock Nd-isotope compositions on these Pale-oproterozoic syntectonic gneissic S-type and A-type granitesand relative rocks provide more evidence on the existence ofArchean basement in Cathaysia Block, which may have beenrecycled or reworked during the extensive Paleoproterozoicand early Mesozoic thermal events in this region.

Acknowledgments

This work was supported by National Basic Research Programof China (2012CB416701) and National Natural Science Foundationof China (Grant 41072043). Two anonymous reviewers are grate-fully acknowledged for their critical and constructive commentsthat have significantly improved the quality of this paper.

Appendix A. Supplementary data

Supplementary data associated with this article can befound, in the online version, at http://dx.doi.org/10.1016/j.precamres.2012.07.001.

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