Geochemistry, geochronology and Sr–Nd–Pb–Hf isotopic compositions of Middle to Late Jurassic syenite–granodiorites–dacite in South China: Petrogenesis and tectonic implications

    Geochemistry, geochronology and Sr–Nd–Pb–Hf isotopic compositions of Middle to Late Jurassic syenite–granodiorites–dacite in South China:Petrogenesis and tectonic implications Bin Li, Shao-Yong Jiang, Qian Zhang, Hai-Xiang Zhao, Kui-Dong Zhao PII: DOI: Reference:

S1342-937X(15)00125-2 doi: 10.1016/j.gr.2015.05.006 GR 1447

To appear in:

Gondwana Research

Received date: Revised date: Accepted date:

6 September 2014 17 April 2015 4 May 2015

Please cite this article as: Li, Bin, Jiang, Shao-Yong, Zhang, Qian, Zhao, Hai-Xiang, Zhao, Kui-Dong, Geochemistry, geochronology and Sr–Nd–Pb–Hf isotopic compositions of Middle to Late Jurassic syenite–granodiorites–dacite in South China:Petrogenesis and tectonic implications, Gondwana Research (2015), doi: 10.1016/j.gr.2015.05.006

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Geochemistry, geochronology and Sr–Nd–Pb–Hf isotopic compositions of Middle to Late Jurassic syenite–granodiorites–dacite in South China：Petrogenesis and

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tectonic implications

Bin Lia,b, Shao-Yong Jianga,b*, Qian Zhangc, Hai-Xiang Zhaod, Kui-Dong Zhaoa a

State Key Laboratory of Geological Processes and Mineral Resources, Collaborative Innovation Center for Exploration

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of Strategic Mineral Resources, Faculty of Earth Resources, China University of Geosciences, Wuhan 430074,China b

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State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing

210093,China

Basic Geological Exploration Co., Ltd, East China Mineral Exploration and Development Bureau, Nanjing210007,

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China d

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Institute of Isotope Hydrology, School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, China

Abstract

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*Corresponding author: Prof. S.Y. Jiang, E-mail address: [email protected]; [email protected]

In situ zircon U-Pb ages and Hf isotope data, major and trace elements and Sr–Nd–Pb isotopic compositions are reported for coeval syenite–granodiorites–dacite association in South China. The shoshonitic syenites are characterized by high K2O contents (5.9–6.1 wt %) and K2O/Na2O ratios (1.1–1.2), negative Eu anomalies (Eu/Eu* = 0.65 to 0.77), enrichments of Rb, K, Nb, Ta, Zr and Hf, but depletion of Sr, P and Ti. The adakitic granodiorite and granodiorite porphyry intrusions are characterized by high Al2O3 contents (15.0–16.8 wt %), enrichment in light rare earth elements (LREEs), strongly fractionated LREEs (light rare earth elements) to HREEs (heavy rare earth elements), high Sr

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(438–629 ppm), Sr/Y (29.2–53.6), and low Y (11.7–16.8 ppm) and HREEs contents (e.g., Yb = 1.29–1.64 ppm). The calc-alkaline dacites are characterized by LREEs enrichment, absence of negative Eu anomalies, and enrichment of

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LILEs such as Rb, Ba, Th, U and Pb, and depletion of HFSEs such as Nb, Ta, P and Ti.

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Geochemical and Sr–Nd–Hf isotopic compositions of the syenites suggest that the shoshonitic magmas were differentiated from parental shoshonitic melts by fractional crystallization of olivine, clinopyroxene and feldspar. The parent magmas may have originated from partial melting of the lithospheric mantle with small amount contribution from

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crustal materials. The adakitic granodiorite and granodiorite porphyry have Sr–Nd–Pb isotopic compositions that are

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comparable to that of the mafic lower crust. They have low Mg# and MgO, Ni and Cr contents, abundant inherited zircons, low εNd(t) and εHf(t) values as well as old whole-rock Nd and zircon Hf model ages. These granodiorites were

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likely generated by partial melting of Triassic underplated mafic lower crust. The Hf isotopic compositions of the dacites

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are relatively more depleted than the Cathaysia enriched mantle, suggesting those magmas were derived from the partial

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melting of subduction-modified mantle sources. The coeval shoshonitic, high-K calc-alkaline and calc-alkaline rocks in Middle to Late Jurassic appear to be associated with an Andean-type subduction. This subduction could have resulted in

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the upwelling of the asthenosphere beneath the Cathaysia Block, which induced partial melting of the mantle as well as the mafic lower crust, and formed an arc regime in the coastal South China during Middle to Late Jurassic.

Keywords: syenite-granodiorite-dacite; paleo-Pacific plate subduction; Jurassic; Cathaysia Block

1 Introduction The South China is characterized by large-scale emplacement of igneous rocks as a result of west-dipping subduction of the paleo-Pacific plate in the Mesozoic (Jahn et al., 1990, 1996; Li and Li, 2007; Zhang et al., 2013; Zhou and Li, 2000). During the Jurassic (Early Yanshanian), extensive granitic magmatisms are distributed in the inland

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discretely in the NE–SW direction and parallel to the present coastline, forming a 600-km-wide intracontinental orogen and post-orogenic magmatic belt in South China (Fig. 1; Huang et al., 2011; Li et al., 2003; Li et al., 2007a, b; Zhou et al.,

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2006). Less abundant Jurassic syenites, gabbros and basalts occurred on the two sides of the Chenzhou-Linwu Fault

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within the South China (Fig. 1; Xie et al., 2006; Wang et al., 2008a, 2013a), displaying two arrays, oblique and parallel to the coastal lines, providing useful estimate and constraint of the source characteristics of the Jurassic asthenospheric and lithospheric mantle beneath the South China Block (Wang et al., 2003, 2008a, 2013; Xie et al., 2006; Jiang et al.,

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2009).

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Origin and evolution of felsic rocks attracted the international interests because they carry the information on the tectonic evolution associated with economically significant mineralization, especially in South China (e.g., Li, 2000;

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Zhou and Li, 2000; Li and Li, 2007; Li et al., 2014). However, the origins of I-type granitoids remain subjects of debate

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and disagreement (Roberts and Clemens, 1993; Liégeois et al., 1998; Huang et al., 2013). Models for the generation of

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the I-type granitoids include reworking of sedimentary materials by mantle-derived magmas (Kemp et al., 2007), crystallization–differentiation of basaltic parents (Macpherson et al., 2006), direct partial melting of hydrous

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medium-to-high-K mafic to intermediate meta-igneous rocks (Roberts and Clemens, 1993), mixing of mantle-derived magmas with crustal-derived materials (Dickinson, 1975; Huang et al., 2013), and assimilation of sialic rocks into differentiating basaltic magmas (DePaolo, 1981). By contrast, partial melting of thickened lower crust without any significant contribution of mantle components (Ma et al., 2013) are also contributed to generate I-type granitoids. Subduction in active continental margins or lithospheric extension in post-collisional/post-orogenic settings (Roberts and Clemens, 1993) have been proposed as the two main driving mechanisms for the petrogenetic and tectonic models resulting in such rocks vary accordingly (Huang et al., 2013). However, few studies involved the nature of granites, and few successful cases were well implemented to identify the contribution of the older magmas to continental crust growth and their tectonic regime so far. Particularly, many of the Mesozoic granitoids are highly evolved and significant

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compositional similarity exists among granitoids of temporally different events in South China (e.g., Li et al., 2007a, b), making it difficult to constraint their origins. Based on the mantle source, the petrogenesis of syenites involves complex

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and varied processes in different tectonic settings (e.g., Lan et al., 2011), including partial melting of

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metasomatized/enriched mantle, differentiation of alkaline basalt magma, and magma mixing of lower crust-derived granitic magmas with mantle-derived silica-undersaturated alkaline mafic magmas. However, depleted asthenosphere are

compositions in South China (e.g., He et al., 2010, 2012).

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thought to play a crucial role for generating syenites, a process considered as essential for the origin of syenitic

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South China forms a basin-range type province related to the geodynamics of Late Mesozoic tectonism and granitic magmatism with basin formation due to extensional tectonics in a back-arc setting associated with a subduction of the

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paleo-Pacific plate (Gilder et al., 1991; Li, 2000; Zhou and Li, 2000; Zhou et al., 2006; Li and Li, 2007; Meng et al.,

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2012). Two major driving mechanisms for the genesis of Late Mesozoic magmatism have been proposed, namely, the

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extension-induced deep crustal melting and the underplating of mantle derived basaltic melts (Xu et al., 1999; Li, 2000; Zhou and Li, 2000; Zhou et al., 2006; Liu et al., 2013). However, considerable uncertainties and controversies still

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remain such as crust–mantle interaction models and the nature of the magma sources, the enriched lithospheric mantle evolution and the role of depleted asthenospheric mantle, which lead to different petrogenetic models of Late Mesozoic igneous rocks in SE China (Xu et al. 1999; Dong et al., 2006; He and Xu, 2012). The most widely accepted model interpreted these magmatic events to be the result of subduction of the paleo-Pacific plate in various ways, including normal subduction (Jahn et al., 1990), subduction with changing subduction angles (Zhou and Li, 2000), and a flat-slab subduction followed by a retreat and foundering of the subducted slab (Li and Li, 2007). Although many researchers have discussed the tectonic regime that controlled the Mesozoic magmatism in SE China (Yang et al., 1999; Li, 2000; Zhou and Li, 2000; Dong et al., 2006; Chen et al., 2008; Li et al., 2009b), the magmatic evolution related to the

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subduction of the paleo-Pacific plate and the temporal and spatial variations within the Late Mesozoic magmatic evolution and the magma sources are still controversial issues.

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Coeval felsic and syenitic rocks are distributed in adjacent domains, apparently controlled by a contemporaneous

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tectono-magmatic evolution event. Previous studies preferred to focus on the complexes within a limited region, showing various emplacement ages as a result of multi-stage magma activities. Taking an individual complex suite as a research object is not very ideality to qualify the petrogenesis of different periods and to constraint the tectonic regime accurately.

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In order to resolve these debates, we choose to study the Middle to Late Jurassic magmatic rocks in the inland of

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Cathaysia Block (Fig. 2a), containing the syenite (Dafengnao), granodiorite and granodiorite porphyry (Kuokeng), and dacite (Pinghe). They are geologically ideal objects because of the spatial coexistence of intrusions and subvolcanic

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rocks that are well constrained to be genetically associated with Jurassic magmatism. In this study, we report new U-Pb

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petrogenesis and tectonic setting.

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geochronological, elemental, and Sr–Nd–Pb–Hf isotopic data for these representative samples, to constraint their

2. Geological background

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The Cathaysia Block, located to the east of the Jiangshan–Shaoxing and Pingxiang–Yushan sutures (Fig.1), is one of the two Precambrian continental blocks that together constitute the South China Block (Li et al., 2014; Liu et al., 2013; Wang et al., 2013b; Zhang and Zheng, 2013; Zhang et al., 2013; Hu et al., 2012; Yu et al., 2012). The Cathaysia Block has been considered to have different crustal evolution histories on the two sides of the Zhenghe–Dapu Fault (Xu et al., 2007), and it can be further divided into the inland

and coastal regions (Fig. 1). The basement of Cathaysia Block

mainly consists of Proterozoic meta-volcano-sedimentary and meta-sedimentary rocks (mainly schist and granulitite), and meta-igneous rocks (amphibolite) (Yao et al., 2011; Jiang et al., 2009; Wang et al., 2008b; Wan et al., 2007; Xu et al., 2007). During the early Neoproterozoic, the Cathaysia Block was amalgamated with the Yangtze Block by the Sibao orogenic event at ca. 970–890 Ma (e.g., Li et al., 2009d). After that, continental rifts had been developed in the middle

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Neoproterozoic (Li et al., 1999), producing of voluminous Neoproterozoic continental to neritic marine sediments and tholeiitic mafic rocks (Jiang et al., 2009; Wang et al., 2009). Subsequently, the Cathaysia Block was reworked by two

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intraplate orogenic events during the early Paleozoic (Li et al., 2010) and the early Mesozoic (Li and Li, 2007),

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respectively, producing considerable amounts of granite with estimated outcrop area of 40,000 km 2 (Huang et al., 2011, 2013). Pre-Mesozoic sequences were unconformably overlain by the lower Mesozoic terrestrial clastics as a result of collision between Indochina and South China in response to the Indosinian Orogeny (Chen et al., 2011; Wang et al.,

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~10 Myr quiescence (Li and Li, 2007; Zhu et al., 2010).

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2007a, b; Jiang et al., 2009). The latter Jurassic and Cretaceous orogenies were remobilized from ~196 Ma after about a

Mesozoic magmatism was concentrated in the Cathaysia Block with an oceanward increase (with decreasing age) in

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magmatic activity (Fig. 1) (Zhou et al., 2006). Jurassic extensive granitoids, along with minor basaltic extrusions and

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volcanic rocks, are mainly located in the inland region, comprising a total outcrop area of 75,000 km 2 (Fig. 1) (Zhou et al.,

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2006; Huang et al., 2013; Liu et al., 2013). Previous studies considered that a system of roughly parallel, NE-trending grabens were formed concurrently with the regional magmatism in SE China and was referred to as the ‘Southeastern

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China Basin and Range Province’ (Gilder et al., 1991; Shu, 2012), declaring extension primarily in the late Jurassic through Cretaceous (Gilder et al., 1991; Jiang et al., 2009). However, syn-orogenic shortening deformation and metamorphism under NW–SE compressional settings have occurred, such as a shortening during the earliest Cretaceous (145–137 Ma), generating gneissic granites in the coastal part of Cathaysia Block (Sun et al., 2007; Li et al., 2014). This Jurassic and Cretaceous orogeny was not only attributed to a single extension regime. However, an extensional zone related to the paleo-Pacific plate subduction was proposed as the main regime for the Shi-Hang Zone (characterized as extensional basins and rifts) and OIB-like basaltic rocks and the secular compositional change of Jurassic basaltic rocks in the region (Jiang et al., 2009; Li et al., 2007a, b; He et al., 2010; Huang et al., 2011, 2013).

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The study area is located in the inland Cathaysia Block (Figs. 1 and 2a), containing abundant Triassic and Jurassic magmatic rocks, such as granites, syenites, and basaltic rocks. Several Middle to Late Jurassic felsic plutons are

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distributed, revealing NE-trending, in the late Mesozoic volcanic-intrusive complex belt. The Kuokeng complex, located

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~20km east of the Liancheng County, has an outcrop area of ~20km2 (Fig. 2a). Field observations found that multi-stages of emplacement (Fig. 2b): an early stage intrusion of granodiorite intruded in Middle Jurassic time (ca. 165 Ma; Table 1); a middle-stage intrusion of granodiorite porphyry intruded in Late Jurassic time (ca. 159 Ma; Table 1); and a late-stage

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intrusions of plagiogranite. The granodiorite is gray in color and middle to fine-grained with a porphyritic texture (Fig.

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3a). It consists typically of porphyritic feldspar, quartz, amphibole, and biotite (Fig. 3c, d). The phenocrysts (up to 75% of the whole rock) are up to 5 mm in size. Fresh plagioclase (40~55 vol.%, 1~5 mm) forms plate-like crystals. The

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subhedral orthoclase (10 ~15 vol.%, 1~3mm) and quartz (10 ~ 15 vol.%, 0.2 ~4 mm) are irregular. Mafic minerals are

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mainly sheet-like amphibole and biotite (15 ~ 25 vol. %) (Fig. 3d). The matrix include mainly felsic minerals with a

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small amount of chlorite and sericite minerals. The irregular magnetites (0.1~1mm, up to ~2%) are distributed in the vicinity of the other mafic minerals. Titanite, apatite, zircon are the most common accessory minerals. The granodiorite

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porphyry is gray or light reddish in color (Fig. 3b), and shows porphyritic texture with euhedral to subhedral plagioclase (30~60 vol. %), K-feldspar (10~15 vol. %), amphibole (10~15 vol. %), biotite (~5 vol. %), and quartz phenocrysts (~10 vol. %), scattered in a fine-grained groundmass (0.02–0.5 mm in diameter) of plagioclase, K-feldspar, quartz and minor amphibole, biotite, zircon, magnetite and apatite (Fig. 3e, f). The euhedral tabular plagioclase (~40 vol.%) develops albite twins, showing oscillatory zoning. The subhedral–anhedral K-feldspar (0.5~3 mm) and quartz (~0.5 mm) are irregular and intergrown with other crystalline phases. Amphibole (<5mm) is euhedral to subhedral, and biotite (<2 mm) is platy and euhedral to anhedral (Fig. 3e). The Dafengnao syenite was situated ~10 km northwest of the Quannan County and has an outcrop area of ~20 km2 (He et al., 2010). These syenitic rocks are light reddish in color, middle-grained, mainly composed of perthite, minor

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microcline (~5 vol. %) and interstitial quartz (~3 vol. %), Fe-Ti oxide, apatite, epidote are the most common accessory minerals. The Pinghe dacite occurred at the bottom of the volcanic layers of Douling Fm., discontinuously overlie the

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Middle Jurassic terrestrial sediments of the Zhangping Fm. within the Fengshun basin in southeastern of Fujian Province,

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yielding the Middle Jurassic emplacement age (Guo et al., 2012). These dacite rocks are associated with rhyolitic lavas at the top and volcanic breccia interbeds, forming a total thickness of the volcanic sequences of about 3300 m (Guo et al., 2012). The detailed texture and mineralogy of these syenitic and volcanic rocks are summarized in Table 1.

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3. Sampling and analytical methods

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Nine samples of the granodiorite and granodiorite porphyry have been collected from the surface exposures and the sample locations are shown in Fig. 2b and Table 2. Three samples have been used for geochronological studies, including

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GT-03 and GT-32 (granodiorite from the Kuokeng pluton, lat. N25°43′35″, long. E116°57′32″), and Gt-11-1

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(granodiorite porphyry from the Kuokeng pluton, lat. N25°43′41″, long. E116°57′32″). All coordinates of other samples

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are listed in Table 2. After careful thin section examinations under an optic microscope, the least-altered samples were selected for whole rock geochemical and isotopic analyses and grounded to 200-mesh using an agate mill.

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3.1. Major and trace element analyses

Whole-rock major and trace elements were analyzed at the State Key Laboratory for Mineral Deposits Research in Nanjing University. For major element analyses, mixtures of whole rock powder (0.5 g) and Li 2B4O7+LiBO2 (4.5 g) were made into glass discs and analyzed by X-ray fluorescence spectroscopy (XRF) with an AXIOS Minerals Spectrometer. The analytical uncertainties were generally within 0.1–1% (RSD). For trace element analyses, whole rock powders (50 mg) were dissolved in high-pressure Teflon bombs using a HF + HNO3 mixture and determined by a Finnigan Element II ICP-MS, with analytical uncertainties within 5-10% for most elements. Detailed analytical procedures for trace elements are described by Gao et al. (2003). 3.2. Sr–Nd–Pb isotope analyses

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Whole-rock Sr and Nd isotopic compositions were measured using a Finnigan Triton TI TIMS following the methods of Pu et al. (2005). During the period of laboratory analysis, measurements of NIST SRM-987 Sr standard Sr/86Sr ratio of 0.710254 ±0.000009 (2σ, n=68), and the JNdi-1 Nd standard yielded a

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Nd/144Nd ratio of

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87

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yielded a

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0.512123 ±0.000006 (2σ, n=65). Total analytical blanks were 5×10−11 g for Sm and Nd, and (2∼5)×10−10 g for Rb and Sr. The following parameters were used to calculate the ISr, εNd(t) values and Nd model ages: λRb =1.393×10−11 year−1 (Nebel et al., 2011); λSm =6.54×10−12 year−1 (Lugmair and Marti 1978); (147Sm/144Nd)CHUR =0.1967 (Jacobsen and Wasserburg

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1980); (143Nd/144Nd)CHUR =0.512638 (Goldstein et al., 1984); (143Nd/144Nd)DM =0.513151, (147Sm/144Nd)DM =0.2136 (Liew

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and Hofmann 1988).

Fresh feldspars separated from the granitoid samples were chosen to determine their Pb isotopic compositions. The

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samples were dissolved in Teflon vials with purified HF+HNO3 and then separated using anion-exchange columns with

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diluted HBr as eluent following the procedure described by He et al. (2005). Isotopic ratios of 206Pb/204Pb, 207Pb/204Pb and Pb/204Pb were measured using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) at the

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State Key Laboratory for Mineral Deposits Research in Nanjing University. Thallium was added as an internal standard.

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Repeated analyses of Pb standard NBS981 yielded a 15.4861±0.0005 and a

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Pb/204Pb ratio of 16.9327±0.0005, a

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Pb/204Pb ratio of

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(1998) for NBS981, i.e.,

Pb/204Pb ratio of 36.681±0.001. Using the reference values reported by Galer and Abouchami 206

Pb/204Pb=16.941,

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Pb/204Pb=15.496 and

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Pb/204Pb=36.722, Pb isotopic ratios in samples

were corrected for mass fractionation. 3.3 Cathodoluminescence (CL) imaging of zircon The studied samples were processed through crushing, conventional magnetic and heavy liquid separation to extract zircons for U–Pb dating. Zircons were documented with cathodoluminescence (CL) images to reveal their internal structures. The CL images were taken using a XM-Z09013TPCL detector (manufactured by JEOL, Japan) attached to a JEOL JXA-8230 electron microprobe at the Geological Testing Center of Shandong Bureau, China Metallurgical

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Geology Bureau in Jinan, to assist selecting target spots for U–Pb dating and Hf analyses. The operating conditions were 15 kV accelerating voltage and 20 nA primary beam current.

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3.4. Zircon U–Pb dating and in situ Hf isotope analyses

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U–Pb dating were carried out using an Agilent 7500a ICP-MS equipped with a New Wave Research 213 nm laser

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ablation system at the State Key Laboratory for Mineral Deposits Research in Nanjing University. Mass discrimination of the mass spectrometer and residual elemental fractionation were corrected by calibration against a homogeneous

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zircon standard, GEMOC/GJ-1 (207Pb/206Pb age of 608.5±0.4 Ma，206Pb/238U age of 599.8±4.5 Ma, Jackson et al., 2004).

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Samples are analyzed in ‘runs’ of ca. 15 analyses, which include 10 to 12 unknowns, bracketed by 2 to 4 analyses of the standard. The unknowns include one analysis of a well-characterized zircon standard, Mud Tank (735 Ma, Black and

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Gulson 1978), as an independent control on reproducibility and instrument stability, and a weighted mean age of 738±14

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Ma (2σ, n=18) was obtained for Mud Tank zircon during our routine analyses, which is identical to the reference value

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within analytical precision.. Detailed analytical procedures are similar to those described by Jackson et al. (2004). The raw ICP-MS data were exported in ASCII format and processed using GLITTER. Common Pb contents were evaluated

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using the method described by Andersen (2002). The age calculations and plotting of concordia diagrams were made using Isoplot v. 3.23 (Ludwig, 2003). Zircon Hf isotope analyses were carried out using a Newwave UP193 laser-ablation system, attached to a Neptune multi-collector ICP-MS at the State Key Laboratory for Mineral Deposits Research in Nanjing University. Instrumental conditions and data acquisition were similar to those described by Wu et al. (2006) and Hou et al. (2007). A stationary spot was used for the present analyses, with a beam diameter of either 40 μm or 55 μm depending on the size of ablated zircon domains. In order to correct the isobaric interferences of

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Lu and

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Yb on

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Hf,

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Lu/175Lu and

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Yb/173Yb

ratios (normalizing ratios of 0.02658 and 0.796218, respectively; Chu et al., 2002) were determined. Zircon standard GJ1 was used as the reference standard, with a weighted mean of 176Hf/177Hf ratio 0.282014±0.000012 (2σ) during our routine

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analyses, which is identical to the reference value (0.282013±0.000017) reported by Elhlou et al. (2006). The εHf(t) values were calculated using a decay constant for

Lu of 1.867×10−11 year−1 (Söderlund et al., 2004) and chondritic

Hf/177Hf (0.282785) taken from Bouvier et al. (2008). Depleted mantle

Hf model ages (TDM) were calculated using the measured

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reservoir has a 176Hf/177Hf=0.283250 at present day, with a

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Lu/177Hf ratios of zircon, assuming that the depleted mantle

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present-day values of 176Lu/177Hf (0.0336) and

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Lu/177Hf value of 0.0384 (Griffin et al., 2000). The mantle

extraction model ages (TDMC) for the source rocks of the magma were calculated by projecting initial 176Hf/177Hf ratios of

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the zircon to the depleted mantle model growth line using a mean 176Lu/177Hf value of 0.015 for average continental crust

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(Griffin et al., 2002). 4. Results

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4.1. Major elements

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Major element contents are normalized to 100% on a LOI (loss on ignition) free basis in all diagrams. The

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Dafengnao syenites are silica oversaturated rocks containing quartz, with relatively medium in SiO2 (62.40–64.51 wt. %), low in CaO (0.80–1.94 wt. %), and MgO (0.12–0.28 wt. %), but high in Al2O3 (15.06–18.07 wt. %), Na2O+K2O

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(11.01–11.96 wt. %), and Fe2O3T (4.98–5.48 wt. %). On the Q’-ANOR classification diagram (Fig. 4a), samples of syenite are classified as alkaline quartz syenite. On the total alkali-silica (TAS) diagram, the syenite samples plot in the syenite field, belonging to alkaline series (Fig. 4b). They all have high K2O (5.52–5.85 wt. %), plotting in the shoshonitic series (Fig. 4c). Figure 4d shows the composition of these rocks in terms of their molar ratios of A/CNK and A/NK. Based on these ratios, the syenite samples are metaluminous. The major oxides of the granodiorite and granodiorite porphyry samples are similar to each other. They are all relatively medium in SiO2 (64.05–67.99 wt. %), high in Al2O3 (15.04–16.78 wt. %), Na2O+K2O (6.84–7.75 wt. %), CaO (3.04–3.86 wt. %), and Fe2O3T (3.25–4.34 wt. %), low in MgO (1.21–1.99 wt. %) and TiO2 (0.40–0.69 wt. %), and Mg# values vary from 41 to 48 (Table 2). The granodiorite samples have higher SiO2 than the granodiorite porphyry samples,

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but lower Al2O3 and MgO than the latter. On the Q’-ANOR classification diagram (Fig. 4a), samples are mainly classified as granodiorite. On the total alkali-silica (TAS) diagram, samples plot in the granodiorite and quartz monzonite

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fields (Fig. 4b). They all have high K2O (2.94–3.99 wt. %) and various K2O/Na2O (0.69–1.17), plotting in the high-K

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calc-alkaline series (Fig. 4c). Figure 4d shows the composition of these rocks in terms of their molar ratios of A/CNK and A/NK. Based on these ratios, the granodiorite and granodiorite porphyry samples are metaluminous to weakly peraluminous. All samples show a systematic correlation between SiO2 and major oxides and trace elements, displaying

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homogeneous CaO and Na2O contents (Figs. 4c and 5).

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regular trends of increasing K2O and decreasing TiO2, Al2O3, Fe2O3T, MgO, P2O5, and V with increasing SiO2, but

Dacites have the lowest SiO2 contents, ranging from 62.85 to 63.44 wt. %, highest Al 2O3 (17.03–17.27 wt. %), TiO2

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(0.71–0.72 wt. %), Fe2O3T (5.62–6.03 wt. %), CaO (5.73–6.00 wt. %) and MgO (1.62–1.69 wt. %) contents, but the

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lowest K2O (1.70–2.30 wt. %) and Na2O (1.85–2.58 wt. %) contents, and variable K2O/Na2O ratios ranging from 0.77 to

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1.00 (Fig. 5; Table 2). On the Q’-ANOR classification diagram (Fig. 4a), most of the samples are classified as granodiorite. On the total alkali-silica (TAS) diagram, samples plot in the granodiorite fields (Fig. 4b) and in the

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calc-alkaline series (Fig. 4c). Figure 4d shows the composition of these rocks in terms of their molar ratios of A/CNK and A/NK. Based on these ratios, the dacite samples are metaluminous to weakly peraluminous. 4.2. Trace elements

All the granodiorite and granodiorite porphyry samples exhibit high Sr (>438 ppm), low Y (<16.8 ppm) and HREE contents (e.g., Yb = <1.6 ppm), and the resultant high Sr/Y (29.2–53.6) and (La/Yb)N (10.5–19.5) ratios indicate that the granodiorite and granodiorite porphyry intrusions can be classified as adakitic rocks (Fig. 6a) as defined by Defant and Drummond (1990). These adakitic rocks have relatively low Ni (3.79 to 9.50 ppm) and Cr (7.45 to 21.1 ppm), respectively (Fig. 6c and d).

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The Dafengnao syenite shows similar REE patterns with (La/Yb) N values ranging from 10.9 to 18.1 (Fig. 7a). Also, they display negative Eu anomalies (Eu/Eu* = 0.65 to 0.77), which likely reflect fractionation or accumulation of

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plagioclase. On primitive mantle-normalized trace element diagrams, these syenite samples show enrichments in

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elements such as Rb, K, Nb, Ta, Zr and Hf, but depletions in Sr, P and Ti. Obviously positive Pb anomaly is conspicuous in the Dafengnao syenite samples.

The adakitic granodiorite and granodiorite porphyry have similar Chondrite-normalized REE patterns (Fig. 7c).

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They are characterized by LREE enrichment (ΣLREE=95–176 ppm), steeply inclined with strongly fractionated LREE to

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HREE ratios such as (La/Yb) N ratios of 10.5–19.5, slight fractionation of HREE with (Gd/Yb) N ratios of 1.66–2.14, and absence of negative Eu anomalies with most Eu/Eu* values ranging from 0.85 to 1.06. On primitive mantle-normalized

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spidergrams (Fig. 7d), the samples are enriched in LILE such as Rb, Ba, Th, U and Pb, and depleted in HFSE such as Nb,

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Ta, P and Ti. Moreover, these adakitic rocks have relatively higher La/Yb, La/Sm, Sr/Y and Zr/Y ratios (Fig. 8) than

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those coeval basaltic rocks and average LCC (Lower Continental Crust). Similar to the Kuokeng granodiorite and granodiorite porphyry, the Pinghe dacite is characterized by LREE

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enrichment (ΣLREE=114–119 ppm), steeply inclined with moderately fractionated LREE to HREE ratios such as (La/Yb)N ratios of 11.6–12.2, slight fractionation of HREE with (Gd/Yb)N ratios of 1.85–2.02, and absence of negative Eu anomalies with most Eu/Eu* values ranging from 0.88 to 1.05 (Fig. 7e). On primitive mantle-normalized spidergrams (Fig. 7f), the samples are enriched in LILE such as Rb, Ba, Th, U and Pb, and depleted in HFSE such as Nb, Ta, P and Ti. 4.3 Sr–Nd–Pb isotopic compositions Sr, Nd and Pb isotopic compositions are presented in Table 3 and shown in Fig. 9. The Kuokeng granodiorite porphyry samples have uniform initial

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Sr/86Sr ratios of 0.7085 to 0.7096 and εNd(t) values of −9.3 to −7.8, and their

two-stage Nd model ages vary from 1.58 Ga to 1.70 Ga. The Kuokeng granodiorite samples show uniform initial

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Sr/86Sr ratios of 0.7088 to 0.7092, but variable εNd(t) values from −12.5 to −8.5, and the two-stage Nd model ages vary

from 1.64 Ga to 1.97 Ga. Figure 9a shows a distinctive feature of the isotopic compositions of the granodiorite and

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granodiorite porphyry intrusions, i.e., the εNd(t) values of the granodiorite are comparable with those from the basement

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metamorphic rocks in Cathaysia Block, whereas Nd isotope compositions of the granodiorite porphyry are less evolved than the same basement metamorphic rocks (Table 3 and Fig. 9a). As shown in the t–εNd(t) diagram, granodiorite porphyry samples plot above the evolutionary trend defined by the Proterozoic crust of the Cathaysia Block. Moreover,

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their two stage Nd model ages (1.58 to 1.70 Ga) are much younger than those of the basement metamorphic rocks in the

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Cathaysia Block (1.8 to 2.2 Ga; Chen et al., 1999) (Table 3), and their Sr-Nd isotopic compositions are comparable with the coeval granitoids in the Cathaysia Block (Fig. 9b). The granodiorite samples plot on the two sides of the upper line of

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the evolutionary trend defined by the Proterozoic crust of the Cathaysia Block, and their Sr-Nd isotopic compositions are

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different from the coeval granitoids and evolved to the Lower Crust value (Fig. 9b). 87

Sr/86Sr ratio of 0.7125, plotting

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The Dafengnao syenite has the highest εNd(t) value (+2.2) and the lowest initial

above the CHUR reference line (Fig. 9b), showing some affinities with the Jurassic mafic rocks, associated with depleted

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and enriched mantle beneath the Cathaysia Block. Moreover, their two stage Nd model ages (1.04 to 1.42 Ga) are much younger than those of the basement metamorphic rocks in the Cathaysia Block (1.8 to 2.2 Ga; Chen et al., 1999) (Table 3). All these clearly demonstrate that a substantial amount of mantle material was involved in the generation of the Dafengnao syenite, and that hybridization between depleted and enriched mantle end members took place during the formation of these syenitic intrusions. The granodiorite and granodiorite porphyry samples show similar Pb isotopic compositions, having (206Pb/204Pb)i ratios of 17.54–17.80, (207Pb/204Pb)i ratios of 15.59–15.60, and (208Pb/204Pb)i ratios of 38.10–38.34, and they plot significantly above the North Hemisphere Reference Line (NHRL) and to the left side of the 4.55 Ga geochron line in the (206Pb/204Pb)i vs.(207Pb/204Pb)i diagram (Fig. 9c, d). Overall, the Pb isotopic compositions of these rocks shared different

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affinities with the coeval basaltic rocks and Middle to Late Jurassic pure crust-derived rocks (Wang et al., 2008a; Li et al., 2013).

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4.4 U-Pb geochronology

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Zircon samples GT-03 and GT-32 for granodiorite, and GT-11-1 for granodiorite porphyry were dated by LA–ICP–MS for their U–Pb ages. The U–Pb isotope data are listed in Supplemental Table 1, and selected CL images and weighted 206Pb/238U ages of the zircons are shown in Fig. 10.

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Two samples were selected from the Kuokeng granodiorite for analyses. Zircon crystals from sample GT-03 and

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GT-32 are euhedral, transparent to light yellow in color, with sizes ranging from 40 to 250 μm and length to width ratios of 1:1 to 4:1. Most zircon grains show wide oscillatory zoning in the cores and narrow oscillatory zoning in the rims (Fig.

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10a). These zircons exhibit Th/U ratios from 0.69 to 1.79 (Supplemental Table 1), indicating that they are of magmatic

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origin. Twenty-six analyses of U–Pb ages yielded a concordant

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Pb/238U age of 164.1±1.8 Ma (2σ, MSWD=2.0). This

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age is interpreted as the age of emplacement of the Kuokeng granodiorite. Two homogenous shimmery cores yielded Pb/238U ages of 230 ± 5Ma and 229 ± 4Ma with Th/U ratios of 0.69–1.26, also interpreted as magmatic origin and 206

Pb/238U ages of 238 ± 4Ma and 244 ± 5Ma, respectively. Except for

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inherited. In sample GT-32, two data-points give

these data-points, sixteen analyses of U–Pb ages yielded a concordant 206Pb/238U age of 164.9±2.1 Ma (2σ, MSWD=1.9). Similarly, zircon crystals from sample GT-32 are euhedral show wide oscillatory zoning in the cores and narrow oscillatory zoning in the rims (Fig. 10b). These zircon samples exhibit magmatic origin with Th/U ratios from 0.22 to 3.06 (Supplemental Table 1). Zircon crystals from granodiorite porphyry sample GT-11-1 are euhedral, transparent in color, with sizes ranging from 60 to 300 μm and length to width ratios of 1:1 to 5:1. Zircons from the youngest group show perfect oscillatory-zoned structures of magmatic origin (Fig. 9c). These zircons exhibit Th contents of 84–344 ppm and U contents of 109–563 ppm, with Th/U ratios from 0.31 to 1.45 (Supplemental Table 1), yielding a concordant

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Pb/238U

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age of 159.0±0.6 Ma (2σ, MSWD=2.0). This age is interpreted as the age of emplacement of the Kuokeng granodiorite porphyry. . Seven analyses in sample GT-11-1 scatter in a wide 206Pb/238U age range of 198–368 Ma, with Th/U ratios of

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and they yield a dominant, magmatic age group of ca. 200 to ca. 240 Ma.

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0.06–3.15 (Fig. 10c). In summary, inherited cores of zircons are abundant in the granodiorite and granodiorite porphyry

4.5. Zircon Hf isotope data

In situ Hf isotopic analyses of zircons are listed in Supplemental Table 2. Zircon grains from samples GT-03 and

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GT-32 with ages of ca. 165–164 Ma exhibit variable εHf(t) values from –15.0 to –8.5 and two-stage model ages (TDM2)

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(between 1716 Ma and 2130Ma; Supplemental Table 2). Four older zircon cores with 206Pb/238U ages of ca. 230–240 Ma have variable εHf(t) values of –12.5 to –7.3 and two-stage model ages of 1142 Ma to 1350Ma (Supplemental Table 2).

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Zircon grains from samples GT-11-1 with an age of ca. 159 Ma exhibit an narrow range of εHf(t) values from –13.3 to

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–9.5, and their TDM2 are between 1775 Ma and 2016 Ma (Supplemental Table 2). One oldest zircon core (ca. 368 Ma) has 206

Pb/238U ages of ca. 220–200 Ma have

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a εHf(t) value of –17.6 and a TDM2 of 2440 Ma. Six older zircon cores with

variable εHf(t) values of –14.4 to –7.3 and TDM2 of 1139 Ma to1406 Ma (Supplemental Table 2). In summary, eleven

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oldest zircon cores with 206Pb/238U ages of ca. 368 to 200 Ma from the Kuokeng suites have εHf(t) values of –17.6 to –7.3 with TDM2 of 1139 Ma to 2440 Ma (Supplemental Table 2). Twenty-eight analyses obtained from zircon grains for the Dafengnao syenite sample DFN01 yielded

εHf(t) values

between 5.9 and 9.0. The calculated TDM2 ages of syenite range from 609 Ma to 808 Ma (Supplemental Table 2). Twenty-one analyses obtained from zircon grains for the Pinghe dacite sample 08JH212 yielded εHf(t) values between −4.3 and 1.1, and the calculated TDM2 ages of the syenite range from 1116 Ma to 1463 Ma (Supplemental Table 2). The εHf(t) values of all samples are normalized to 159 Ma on ages in all diagrams, and then shown in Fig. 11. 5. Discussion 5.1. Petrogenesis of the shoshonitic syenite

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The SiO2 contents of the Dafengnao shoshonitic syenites are too high (62~65 wt. %) to represent magmas derived by direct partial melting of the mantle, as the latter cannot yield melts more silicic than the andesitic compositions

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with >57 wt. % SiO2 (Baker et al., 1995). The Dafengnao syenites have depleted Sr–Nd–Hf isotopic compositions with

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positive εNd(t) and εHf(t) values (Fig. 9a, b). In terms of Sr–Nd isotopes, the melts parental to the Dafengnao syenites were considered as being derived from mixing of predominantly depleted asthenosphere-derived magmas with melts from enriched lithospheric mantle (e.g., He et al., 2010). However, several lines of evidence suggest that lithospheric

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mantle-derived alkali-rich melts mainly contributed to their parental melts, most likely the shoshonitic melts, are

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genetically associated with with hydrous phases such as amphibole or phlogopite (Jiang et al., 2006), including: (1) these syenites and coeval mafic suites in inland Cathaysia Block show close proximity and a coeval nature (He et al., 2010;

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Wang et al., 2008a); (2) their Sr–Nd isotopic compositions are similar to the coeval mafic magmas, which was widely

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considered to be derived from lithospheric mantle source (Li et al., 2009b) (Fig. 9b);

(3) The syenite samples plot away

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from the binary mixing curve between depleted mantle and enriched lithospheric mantle represented by the Yangfang syenites, precluding the magma mixing progress. Moreover, the Yangfang aegirite-augite syenite represents the enriched

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subcontinental lithospheric mantle of South China, which was modified by the subduction of the paleo-Pacific plate. The Dafengnao syenites have depleted isotopic signatures with significantly higher whole-rock εNd(t) and zircon εHf(t) values than the Yangfang aegirite-augite syenites. Cosidering their different REE and trace element patterns, incoherent, and unparallel to those of the Yangfang aegirite-augite syenite, the Dafengnao syenite could be precluded as a subduction-related metasomatically enriched mantle origin There is a close match in the Nd and Hf isotopic compositions of the syenites and the coeval Qinghu monzonites within the hinterland Cathaysia Block (Fig. 9b; Li et al., 2009b), indicating that these samples might have a similar source composition. The Qinghu monzonites were most plausibly derived by partial melting of recently metasomatized lithospheric mantle without any crustal contamination (Li et al., 2009b). It is likely that the Dafengnao syenites were derived from partial melting of an unmodified lithospheric mantle,

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although processes similar to those invoked for the Qinghu monzonites. However, the difference is the involvement of hybridization with crustal materials as supported by evidently positive Pb and higher initial 87Sr/86Sr, lower εNd(t) values

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(Figs. 7b and 9). Their La/Nb ratios (0.9 to 1.3) are higher than the Qinghu monzonites, indicating minor crustal

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contamination. We thus suggest that the Dafengnao syenites were likely produced by partial melting of recently metasomatized mantle sources by interaction with minor crustal materials.

Low MgO, Ti2O, Ni, Cr, V and high SiO2 imply significant fractionation of olivine and clinopyroxene for the

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shoshonitic syenites from these mantle-derived melts (Figs. 5 and 6). In addition, plagioclase might have been another

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fractionated phase given the relatively low Eu/Eu* values of 0.77–0.80 (Table 2), coupled with low Sr/Y ratios and Ba, Sr, Eu contents. The Dafengnao shoshonitic syenites have similar and limited variations in La/Yb (15–16) and Dy/Yb

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(2.0–2.1) with increasing SiO2, consistent with differentiation from a shoshonitic mafic melt by olivine, clinopyroxene

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and plagioclase dominated fractional crystallization (Macpherson, 2008) (Figs. 5i and 8). These uniform La/Yb and

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Dy/Yb ratios can also suggest that amphibole and garnet were probably not involved in magmatic differentiation (e.g., Lu et al., 2013). In addition to fractionation, it is important to consider the possible effects of crustal contamination before

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trying to assess the mantle source characteristics and melting histories of the shoshonitic rocks. Although “crustal-like” geochemical features, such as the positive Pb anomaly, are preserved within the Dafengnao syenite, the characteristics of similar REE contents and Chondrite-normalized REE patterns, and absence of negative Nb, Ta, and Zr anomalies indicate only a minor crustal contamination. The basalts and syenites exhibit insignificant subduction features, indicating that the mantle beneath the inland Cathaysia Block has not been modified by the paleo-Pacific subduction system during this period, and characterized by a convective asthenosphere. We propose that the intensive magmatism in the inland Cathaysia Block during the Early to Middle Jurassic may have been resulted from upwelling of the asthenosphere mantle under extensional tectonic setting probably as a response to the continuous Pacific plate subduction began during Triassic (Wang et al., 2005).

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5.2. Petrogenesis of the Kuokeng high-K calc-alkaline granodiorite and granodiorite porphyry These adakitic high-K calc-alkaline rocks contain hornblende, mainly metaluminous to weakly peraluminous with

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A/CNK < 1.1 (Fig. 4d), which indicate that they belong to I-type granite (Chappell, 1999). Adakitic magmas derived

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directly from partial melting of the subducted oceanic slab usually show characteristics of high Na 2O rather than high K2O, as demonstrated by experimental studies (e.g. Defant and Drummond, 1990). The Sr–Nd–Hf isotopic compositions of the Kuokeng samples plot away from the field of depleted mantle and the Jurassic mafic rocks (Fig. 9b), coupled with

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the high K2O/Na2O ratios (Table 2), suggesting that the Kuokeng granodiorite and granodiorite porphyry were not

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oceanic slab-derived adakits that are inferred to have interacted with the mantle wedge during ascent (e.g. Rapp et al., 1991). The delamination model of lower crust can also be excluded for the petrogenesis for the Kuokeng granodiorites,

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because the concentrations of Cr, Ni, and Mg# will elevate significantly as a result of melts of delaminated lower crust

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interacting and equilibrating with the mantle peridotite inevitably (Kelemen, 1995). The low abundances of these

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elements in the present adakitic granodiorites are inconsistent with such interactions (Fig. 6c, d and Table 2). Furthermore, samples plot outside the field of meta-basaltic and eclogite experimental melts hybridized by peridotite,

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which represent delaminated lower crust-derived adakitic rocks in Fig. 6b. The Kuokeng samples plot below the binary mixing curve between depleted mantle and crustal materials represented by the Darongshan granite, precluding the delamination model and magma mixing progress. The Pb isotopic compositions (Fig. 9c, d) show that the Kuokeng samples plot away from the field of coeval mafic rocks and the Middle to Late Jurassic crustal-derived rocks in the inland Cathaysia Block (Li et al., 2013), all of which argue against the mixing model. The εHf(t) values of the zircons for the Kuokeng rocks show narrow distributions (Fig. 11b and c), suggesting that these granodiorites were not derived from mixing with mafic magmas. Additionally, melts formed directly by low degree partial melting of metasomatized lithospheric mantle are generally shoshonitic in composition (Jiang et al., 2006), but this mechanism can therefore be ruled out for the origin of the Kuokeng granodiorites because they are high-K calc-alkaline (Fig. 4c). Moreover, their

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REE and trace element patterns are obviously different from those of the Triassic Yangfang aegirite-augite syenites in Fujian Province, which are widely considered to be derived from enriched lithospheric mantle (Fig. 7; Wang et al., 2005).

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The Kuokeng samples also probably did not originate from assimilation and fractional crystallization of the

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mantle-derived mafic magma or crystal fractionation of the water-rich basaltic magma. Among the Jurassic basaltic rocks in the Cathaysia Block, no coexisting coeval basaltic rocks were found in the Fujian Province so far. Additionally, the Kuokeng samples have the significantly lower εNd(t) values than the Jurassic basalts (Fig. 9b); Feldspar fractionation is

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also precluded by the absence of Eu and Sr anomalies. As shown in Figure 9b, samples plot far from granites derived

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from the upper-crustal sources (ie., the Darongshan granite), implying that the silicic upper-crustal materials provided little or no contribution to the adakitic magmas. Furthermore, on the La/Yb vs. La and La/Sm vs. La diagrams (Fig. 8a, b),

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the Kuokeng samples (granodiorite and granodiorite porphyry) plot along a partial-melting array that differs from the

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pattern of the coeval mafic rocks from Cathaysia Block (Wang et al., 2008a), showing continuous trends and suggesting

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that the effects of partial melting and source composition were more important than the fractional crystallization in controlling the compositional variation.

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The Kuokeng adakitic granodiorites were most likely derived by partial melting of the thickened mafic lower crust. This interpretation is supported by the following lines of evidence: (1) their low MgO, Ni, and Cr contents are similar to those of the thick lower-crust derived adakitic rocks and the meta-basaltic and eclogite experimental melts (Fig. 6b-d; Wang et al., 2006); (2) their high K2O contents fit well within the fields of experimental melts of medium-K and high-K amphibolites (Rapp et al., 1991; Sen & Dunn, 1994; Xiong et al., 2005); (3) their samples have the lowest εNd(t) and εHf(t) values as well as the oldest whole-rock Nd and zircon Hf model ages (Figs. 10a,11b-d and 12). The batch melting modeling was conducted to simulate the (La/Yb) N vs. Yb variations, following the methods of Li et al. (2009a). Their samples exhibit strong fractionation between LREE and HREE [(La/Yb) N = 5.2–32.6] and lack of negative Eu anomalies, indicating that the existence of garnet or amphibole as residue phases will lead to melts with low

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concentrations of HREE (Defant and Drummond, 1990). On the (La/Yb)N vs. Yb diagram, samples plot off the partial melting curves, which suggest that these samples might have a different source composition (Fig. 6a). The variations for

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the adakitic granodiorites broadly follow the trends between partial melting restite with amphibole eclogite and 10%

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garnet amphibolite (Fig. 6a). Moreover, high Sr/Y (Fig. 8c) and Zr/Y (Fig. 8d) ratios, low HREE concentrations (YbN< 3.7), and the fractionated HREE patterns (Dy/Yb = 1.7–2.0) of the adakitic granodiorites (Fig. 5i; Table 2), suggest that the residual garnet played an important role for the petrogenesis. Besides, the Nb/Ta ratios of the Kuokeng granodiorite

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and granodiorite porphyry vary from 11 to 15, in consistent with the continental crust (12–13, Rudnick and Gao, 2003).

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This indicates the absence of residual rutile in the magma source of these adakitic rocks (Ma et al., 2013). That is because melt in equilibrium with residual rutile at the time of melting will be characterized by high Nb/Ta ratios (e.g., Ma et al.,

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2013). The existence of a positive correlation between Hf/Sm and Sr/Y, Hf/Sm and Zr/Y (Fig. 8c, d; Table 1), indicates a

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significant role of garnet and/or hornblende during melting.

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However, the Sr–Nd isotopic compositions of these adakitic rocks are not strikingly identical with the Proterozoic crust of the Cathaysia Block (Fig. 9a, b), precluding their formation by direct remelting of the ancient lower crustal

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sources. Moreover, the εHf(t) values of the 165–159 Ma magmatic zircons in the adakitic rocks mostly vary from −15.0 to −8.5 with the corresponding two-stage Hf model ages of 1.72–2.14 Ga, which are not consistent with those of the basement metamorphic rocks in the Cathaysia Block (>1.85 Ga; Xu et al., 2007) (Fig. 12). To sum up, the basement metamorphic rocks of Proterozoic lower crust was precluded as the unique source for the adakitic rocks. Abundant inherited zircon cores from the host adakitic granodiorites record a dominant Triassic spectrum of magmatic ages at 244 to 198 Ma with hardly any magmatic/metamorphic ages dispersed from pre-Triassic. Comparable Hf isotopic compositions between the inherited zircon cores [εHf(159 Ma) = −15.2 to −8.6] and the ca. 240 to 200 Ma zircon rims [εHf(159 Ma) = −15.3 to −8.1] suggest that the wall-rock assimilation, if any, is insignificant (Fig. 11). Incomplete melting of source rocks could be proposed to explain the inherited zircon cores in the host adakitic granodiorites.

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Inherited zircons share a close affinity in two-stage model ages with the 165–159 Ma zircons too (Fig. 12). In spite of an age range of 224 to 198 Ma in detrital zircon age spectra of some shallow terrestrial basin sediments (Li and Li, 2007),

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melting of this sediment-dominated source is unlikely as absence of other age peaks of pre-Triassic. This older crustal

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component is unlikely to have been supracrustal material (such as metasedimentary rocks) and Precambrian basement lower curst material. Therefore, these inherited zircons most likely originated from partial melting of the underplated Triassic mafic lower crust. It is likely that the Kuokeng high-K calc-alkaline adakitic granodiorite and granodiorite

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porphyry were derived from partial melting of the Triassic underplated mafic lower crust, through process similar to

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those K-rich adakitic rocks that were produced by partial melting of the amphibole-bearing ecologites with a K-rich mafic bulk composition under a compressional environment (e.g., Wang et al., 2005). There is a close match in the Sr

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and Nd isotopic compositions of the potassic adakitic rocks and the Yangfang syenites (Fig. 9b), indicating that the

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Triassic enriched mantle may be the primary source of those underplated mafic lower crust. The presence of inherited

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zircons with ages of 368 Ma indicates that there is an older crustal component involved in the genesis of the potassic adakitic rocks in the source (Figs. 10c and 12).

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The Kuokeng samples are characterized by strong fractionation between LREE and HREE, enrichment of LILEs and depletion of HFSEs with negative Ta, Nb and Ti anomalies (Fig. 7d), which are the common features of arc-like magmas (Chen et al., 2008; He and Xu, 2012; Meng et al., 2012; Zhou et al., 2006). The high La/Nb (1.3–3.1) and Ba/Nb (40–83) ratios of the samples are also similar to arc volcanics (e.g., sanukitoids and adakites) (Jahn et al., 1999), indicating that the Triassic underplated basaltic materials were associated with subduction processes. The Nb/U ratios (1.9–6.0) of the samples are significantly lower than that of MORB (middle ocean ridge basalt) and OIB (ocean island basalt) (~47; Hofmann et al., 1986), and also lower than the estimates for continental arc volcanics (Nb/U =12; Kelemen at al., 2003), and LCC (lower continental crust) (Nb/U = 25; Rudnick and Gao, 2003). These trace element constraints provide a strong link with subduction-related melting to form the underplated mafic lower crust (Ayers, 1998). Their

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enriched Sr–Nd–Hf isotopic compositions are coinciding with the involvement of the arc-like basaltic magmas, which were probably inherited from those Triassic underplated subduction-related lower crust. This implies that the Triassic

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magmatism in the Cathaysia Block (at least in Fujian Province) was related to oblique subduction of the Pacific plate

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underneath South China (Wang et al., 2005). 5.3. Petrogenesis of the Pinghe calc-alkaline dacite

The Pinghe dacite rocks are calc-alkaline and I-type in composition, have uniform silica contents (SiO 2 = 62.9–63.4

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wt. %) and relatively low Mg# (36–37), both of which indicate that they are not in equilibrium with primary mantle melts.

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Their Hf isotope compositions, positive Sr anomalies and absence of Eu anomalies (Fig. 7e, f), and high Sr/Y and Zr/Y ratios (Fig. 8c and d) preclude their derivation solely from pure crustal materials. Although fractional crystallization

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could generate a wide variety of rock types, homogeneous major and trace elements contents, and high Eu/Eu* values,

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suggesting these rocks have not undergone any significant feldspar fractionation. Meanwhile, these rocks have not

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undergone any significant fractionation of zircon, apatite, and titanite or rutile as indicated by the absence of Zr, Hf, P, Sm anomalies (Fig. 7e,f) (Klemme et al., 2005). Therefore, the characteristics of HREE, Nb, Ta and Ti depletion are

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likely to be intrinsic to their parental magma sources as a result of precluding the zircon and rutile fractionation (Xiong et al., 2005). The mixing progress is also precluded by the absence of MMEs and inherited zircons, and less variation of εHf(t) values (Fig, 11f).

Here, we argue that the geochemical and isotopic characteristics of the Pinghe dacite were likely derived from a subduction-related magmatic arc source as supported by petrographic and geochemical evidence. The evidence for this arc magma includes the following: (1) these samples are characterized by strong fractionation between LREE and HREE, enrichment of LILEs and depletion of HFSEs with negative Ta, Nb and Ti anomalies (Fig. 7e, f), which are the common features of the arc-like basaltic rocks (Kelemen et al., 2003); (2) these calc-alkaline felsic and Andean basaltic rocks have the almost identical, coherent, and parallel REE and trace element patterns (Fig. 7e, f; Kelemen et al., 2003); (3) high

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La/Nb and Ba/Nb ratios of these samples are also similar to arc volcanics (e.g., sanukitoids and adakites), indicating that the dacites were associated with subduction processes (Table 2; Jahn et al., 1999); (4) the low Nb/U ratios (3.3–3.9) of

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these samples indicate the involvement of subduction-related fluids; (5) the calc-alkaline dacites have higher Cr contents

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than the thickened lower crust-derived adakitic rocks at the same SiO2 contents, also suggesting magmas evolved from subduction-related mafic melts (Fig. 6d).

It is noteworthy that the zircon Hf isotopic compositions of the calc-alkaline dacites are relatively more depleted

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than the enriched mantle underneath the Cathaysia Block (Figs. 11f and 12). These depleted εHf(t) values imply a

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significant contribution of mantle source to the parental magmas of these rocks. Whereas some enriched Hf isotopic signatures of these samples further indicate that the enriched component, which was added to the mantle source, came

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largely from the dehydration of subducted sediments and/or fluids (Ayers, 1998). We conclude that the source of these

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Andean-type arc-like dacites is an isotopically mantle metasomatized by subducted fluid and sedimentary materials. High

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SiO2 and Sr contents and absence of Eu anomalies might suggest that these rocks were derived from partial melting of a subduction-modified mantle with the residual phases of garnet rather than plagioclase.

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6. Geodynamic implications

Mesozoic Cathaysia Block experienced two dominantly tectonic regimes: Triassic orogeny and Jurassic to Cretaceous magmatic episode related to paleo-Pacific plate subduction (e.g., He et al., 2010; Li et al., 2012; Wang et al., 2013a). Early Triassic orogeny is referred to as the oblique collision of Indochina with South China Block (e.g., Carter et al., 2001; Metcalfe, 2002). The Paleotethyan Ocean became progressively closed in association with the Triassic South China continental collision. This intracontinental orogeny shows a succession of events involving early Middle Triassic thrusting-related transpression and development of a large scale flower structure that developed in a regime of oblique regional convergence, resulting in the development of NW/WNW-trending structural elements and associated metamorphism and magmatism (He et al., 2010; Wang et al., 2013a). During the Late Triassic, a tectonic transition inside

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the South China Block from contraction to extension, formed an over thickened gravitationally unstable crustal segment (Wang et al., 2007a, b). Moreover, the Early Triassic granites (243–228 Ma) were thought to be generated by partial

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melting of thickened crust during the post-collisional episode under compressional conditions, induced by in situ

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radiogenic heating or increased geothermal gradient (Wang et al., 2007a, b). The Late Triassic granites (220–206 Ma) were interpreted as dehydration melting of the crustal materials in a post-orogenic extensional setting (Wang et al., 2007b). Underplating of mantle-derived magmas was thought to have provided extra heat for the crustal melting during

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this period (Dai et al., 2008). However, dextral and sinistral shearing structural observation along the southern and

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northern margins of the South China Block indicated an eastward extrusion (e.g., Lepvrier et al., 2011). In addition, Triassic magmatic records from the Palawan terrane have been inferred as a result of the subduction/obstruction of the

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paleo-Pacific plate (e.g., Ferrari et al., 2008). The transtension along the NE-trending strike-slip fault zones probably

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existed from at least the latest Permian into the Triassic, which was related to oblique subduction of the Pacific plate

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underneath the South China Block (Wang et al., 2005) and the continental arc magmatism probably started as early as the middle Permian (Li et al., 2006). Further studies indicated that pre-Jurassic to Early Jurassic subduction of paleo-Pacific

2007).

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plate could approach as far as the Yangtze Block (e.g., Jahn et al., 1990; Zhou and Li, 2000; Li et al., 2006; Li and Li,

In the R1–R2 classification diagram (Fig. 13), data for all samples from these arc-like dacites plot in the pre-plate collision field, as do data for the adakitic granodiorites. These rocks are interpreted to have emplaced in a continental arc setting in the Middle Jurassic. Late Jurassic adakitic granodiorite porphyry plots in the pre-plate collision to post-collision uplift fields in the region, suggesting that these rocks were formed in a compression regime. In comparison, data for the Dafengnao syenite samples plot in the field of late orogenic, indicating an intra-continental extensional environment. In summary, both the arc-like dacites and adakitic granodiorites were most likely generated in a continental arc setting, whereas the syenites were formed in a back-arc extensional setting.

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As discussed above, the Kuokeng adakitic rocks involved melting of a thickened mafic lower crust with Triassic mafic domains (Fig. 14). This indicated that the existence of paleo-Pacific subduction within the Cathaysia Block during

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the Triassic, in consistent with such mafic domains having the characteristics of subduction modification. Middle to Late

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Jurassic crustal thickness beneath western Fujian Province was >50 km because of the presence of eclogite or garnet-bearing amphibolite as the residual phases accompanied by partial melting of this thickened lower crust with the residual phases (Sen and Dunn, 1994). However, the crustal thickness beneath the western Fujian Province is currently

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and been thinned by at least ~20 km since the Cretaceous.

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~30 km (Zhang and Wang, 2007; Guo et al., 2012). Therefore, the crustal thickness appears to have changed significantly

Minor late Middle Jurassic to Late Jurassic sedimentary sequences occur in the South China Block, reflecting uplift

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and erosion of the crust during this period (e.g., Chen et al., 2007). A series of NNE striking thrusts and folds as a result

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of an Early Jurassic event were marked by deformation within the Paleozoic and Early Mesozoic sequences (Xu et al.,

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2009; Zhang et al., 2009; Xu and Zhang, 2011). The Early Cretaceous volcaniclastic strata unconformably overlie the Early Mesozoic sequences (Chen et al., 2007; Wang et al., 2008a). In addition, two Jurassic NE-trending A-type granite

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belts also exist in the inland Cathaysia Block with high εNd(t) values, implying significant mantle contributions (Fig. 1; Jiang et al., 2009; He et al., 2010; Huang et al., 2011). Low Y/Nb ratios (0.83–1.14) of Early Jurassic A-type granites (He et al., 2010) have been consistent with rift-related A1-type granite (Eby, 1992). Late Mesozoic igneous magmatism in SE China was attributed to a widely accepted active continental margin along the coastal region (e.g., Zhou et al., 2006), with or without a previous flat-slab subduction (e.g., Chen et al., 2008; Li and Li, 2007). Li and Li (2007) suggested a flat subduction model for the generation of all the Mesozoic granitoids in the Cathaysia Block to paleo-Pacific subduction and ascribed the generation of Middle-Late Jurassic granitoids to “slab break-off and foundering” as a consequence of rollback of the retreating flat subduction. There are no known Late Triassic adakitic rocks, and the resumption of syenitic and A-type granitic intrusions cannot support the conclusion that the granitic magmatic evolution

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in the Cathaysia Block during the Mesozoic followed such a pattern (Chen et al., 2008). Mafic suites within the Cathaysia Block decrease in age eastward in the Mesozoic and they were mainly mixtures of melts derived from

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OIB-like asthenospheric mantle and the South China subcontinental lithosphere mantle without being significantly

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modified by subduction and crustal contamination during their transition to the surface (Chen et al., 2008). The flat subduction model for the paleo-Pacific plate is therefore not convincing. To sum up, the eastern Cathaysia Block was tectonically under compression during the Middle to Late Jurassic. Basaltic and syenitic rocks are of within-plate

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(anorogenic) origin without subduction-related magmatism (e.g., Jiang et al., 2009; He et al., 2010), precluding a model

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of westward flat-slab subduction of the Pacific plate during the Jurassic (Li and Li, 2007; Huang et al., 2011, 2013; Li et al., 2012; Meng et al., 2012).

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We propose a simplified genetic model for the syenite–granodiorites–dacite association of 166 Ma to 159 Ma in the

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Cathaysia Block, and it is confirmed that an Andean-type subduction, genetically associated with paleo-Pacific plate (Fig.

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14). Paleomagnetic data indicated that the convergence was northwest-ward (Gilder et al., 1996). The slab-released fluids may have triggered partial melting of the asthenosphere to form the parent magmas of the Middle Jurassic Pinghe dacites.

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Melting of the thickened lower crust generally requires input of mantle heat (Petford and Gallagher, 2001). A strong slab rollback towards vertical increases subduction rate accompanied with the subduction (Niu et al., 2003), trench retreat and extension of the overriding plate locally occur (Chen et al., 2014), and give rise to thinning of the overriding plate as a result of rheologically weakened by arc magmatism (Nikolaeva et al., 2008). This process will induce decompression melting of asthenosphere mantle (e.g., Chen et al., 2014). The oblique convergence of the paleo-Pacific plate to Cathaysia Block would have triggered reactivation of pre-existing faults or zones of lithosphere weakness; underplated basaltic magmas gave rise to partial melting of the Triassic underplated mafic lower crustal rocks with arc signatures, to generate the Kuokeng adakitic plutons (Fig. 14). The Dafengnao syenite might have been formed by partial melting of the lithospheric mantle due to upwelling asthenosphere and lithosphere extension

(Fig. 14). In addition, the intra- or

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underplating of the mantle-derived magmas provided sufficient heat to enhance the geothermal gradients, and the granitic magmas could undergo significant differentiation to form large-scale granites. Jurassic magmatic activities along the

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South China coastal line are likely products of crustal anatectic melts under compressional regimes of the paleo-Pacific

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plate subduction (He et al., 2010). 7. Conclusions

(1) Spatially related, coeval syenite–granodiorites–dacite association occurs in the Cathaysia Block, recognized on

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the basis of field relationships and their major and trace element compositions. This association was emplaced in Middle

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to Late Jurassic, including Middle Jurassic syenite–granodiorite–dacite and the Late Jurassic granodiorite porphyry. The shoshonitic syenites are characterized by high K2O contents (5.9–6.1 wt. %) and K2O/Na2O ratios (1.1–1.2). The adakitic

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granodiorite and granodiorite porphyry are both characterized by high Sr (438–629 ppm) contents, Sr/Y (29–54) ratios,

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and low Y and Yb contents. The calc-alkaline dacites are characterized by enrichment in LREE and LILE, and depletion

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in HFSEs, with negative Nb, Ta, Ti and P anomalies. (2) The syenites were likely derived by partial melting of recently metasomatized mantle sources by interaction with

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minor crustal materials. Fractionation of olivine, clinopyroxene and plagioclase controlled evolution of the mantle-derived melts to produce these shoshonitic syenites. (3) The adakitic granodiorite and granodiorite porphyry have similar Sr–Nd–Pb–Hf isotopic compositions, low Mg# and MgO, Ni and Cr contents, abundant inherited zircons, low εNd(t) and εHf(t) values as well as old whole-rock Nd and zircon Hf model ages. These adakitic rocks were most likely derived by partial melting of the underplated mafic lower crust. These adakitic samples show the common features of arc-like magmas that might have inherited from the Triassic underplated mafic rocks, suggesting these older domains were derived from subduction-related melts, indicating that a probably subduction of the paleo-Pacific plate had occurred during Triassic.

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(4) The calc-alkaline dacites have the geochemical and isotope characteristics of arc-like magmas, which are

Collectively,

the

geochemical

and

Sr–Nd–Pb-Hf

isotope

signatures

are

consistent

with

the

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(5)

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partial melting of a subduction-modified mantle with the residual phases of garnet.

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consistent with their major, trace elements and Hf isotope compositions. It is suggested that they were derived from

syenite–granodiorites–dacite association being associated with an Andean-type subduction and the upwelling of asthenosphere during Middle to Late Jurassic underneath the Cathaysia Block, which emphasized the primary role of

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asthenospheric mantle upwelling and heating induced the partial melting of the lithospheric mantle as well as the mafic

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lower crust. The subduction of paleo-Pacific plate might be traced back to the Triassic to account for the genesis of these rocks. It is likely that a local intraplate extension environment in the inland Cathaysia Block and a passive continental

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margin setting along the present coastline of the South China during Middle to Late Jurassic.

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Acknowledgements

We thank Dr. Ming-Lan Hou for the help with zircon CL image, Bin Wu with LA-ICP-MS U–Pb dating, Tao Yang with LA-MC-ICP-MS Lu–Hf analyses, and Wei Pu with Sr–Nd–Pb isotope analyses. This work is supported by projects

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from Major State Basic Research Program of China (2012CB406706) and National Natural Science Foundation of China (No. U1405232 and 41203011). Prof. A.W. Hofmann and Prof. Klaus Mezger gave comments and suggestions to an early version of the paper. Prof. Shou-jie Liu and two reviewers also provided valuable comments and suggestions to this manuscript which improved it significantly.

References Andersen, T., 2002. Correction of common lead in U–Pb analyses that do not report

204

Pb. Chemical Geology 192,

59–79.

29

ACCEPTED MANUSCRIPT 30

Ayers, J., 1998. Trace element modeling of aqueous fluid–peridotite interaction in the mantle wedge of subduction zones. Contributions to Mineralogy and Petrology 132, 390-404.

SC R

experiments and thermodynamic calculations. Nature 375, 308-311.

IP

T

Baker, M.B., Hirschmann, M.M., Ghiorso, M.S., Stolper, E.M., 1995. Compositions of near-solidus peridotite melts from

Barry, T.L., Kent, R.W., 1998. Cenozoic magmatism in Mongolia and the origin of central and east Asian basalts. In: M.F.J. Flower, S.L. Chung, C.H. Lo and T.Y. Lee, eds., Mantle Dynamics and Plate Interactions in East Asia.

NU

American Geophysical Union Geodynamics Series. Washington, D. C, AUG, 27,347-364.

MA

Batchelor, R.A., Bowden, P., 1985. Petrogenetic interpretation of granitoid rock series using multicationic parameters. Chemical Geology 48, 43-55.

D

Black, L.P., Gulson, B.L., 1978. The age of the mud tank carbonatite, strangways range, northern territory. BMR Journal

TE

of Australian Geology and Geophysics 3, 227-232.

CE P

Bouvier, A., Vervoort, J.D., Patchett, P.J., 2008. The Lu–Hf and Sm–Nd isotopic composition of CHUR: constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets. Earth and Planetary

AC

Science Letters 273, 48-57.

Boynton, W.V., 1984. Geochemistry of the rare earth elements: meteorite studies. In Henderson, P, eds., Rare Earth Elements Geochemistry. Amsterdam, Elservier 2, 63-144. Carter, A., Roques, D., Bristow, C., Kinny, P., 2001. Understanding Mesozoic accretion in Southeast Asia: significance of Triassic thermotectonism (Indosinian orogeny) in Vietnam. Geology 29, 211-214. Chappell, B.W., 1999. Aluminium saturation in I- and S-type granites and the characterization of fractionated haplogranites. Lithos 46, 535-551.

30

ACCEPTED MANUSCRIPT 31

Chen, C.H., Hsieh, P.S., Lee, C.Y., Zhou, H.W., 2011. Two episodes of the Indosinian thermal event on the South China Block: Constraints from LA-ICP-MS U-Pb zircon and electron microprobe monazite ages of the Darongshan S-type

IP

T

granitic suite. Gondwana Research 19, 1008-1023.

40

SC R

Chen, C.H., Lee, C.Y., Shinjo, R., 2008. Was there Jurassic paleo-Pacific subduction in South China?: Constraints from Ar-39Ar dating, elemental and Sr–Nd–Pb isotopic geochemistry of the Mesozoic basalts. Lithos 106, 83-92.

Chen, J.F., Guo, X.S., Tang, J.F., Zhou, T.X., 1999. Nd isotopic model ages: implications of the growth of the

NU

continental crust of southeastern China. Journal of Nanjing University (Nature Science) 35, 649-658 (in Chinese,

MA

with English abstract).

Chen, R., Xing, G.F., Yang, Z.L., Zhou, Y.Z., Yu, M.J., Li, L.M., 2007. Early Jurassic zircon SHRIMP U–Pb age of the

D

dacitic volcanic rocks in the southeastern Zhejiang Province, determined firstly and its geological Significances.

TE

Geological Review 53, 32-35 (in Chinese with English abstract).

CE P

Chen, Y.X., Song, S.G., Niu, Y.L., Wei, C.J., 2014. Melting of continental crust during subduction initiation: A case study from the Chaidanuo peraluminous granite in the North Qilian suture zone. Geochimica et Cosmochimica Acta

AC

132, 311-336.

Chu, N.C., Taylor, R.N., Chavagnac, V., Nesbitt, R.W., Boella, R.M., Milton, J.A., German, C.R., Bayon, G., Burton, K., 2002. Hf isotope ratio analysis using multi-collector inductively coupled plasma mass spectrometry: an evaluation of isobaric interference corrections. Journal of Analytical Atomic Spectrometry 17, 1567-1574. Dai, B.Z., Jiang, S.Y., Jiang, Y.H., Zhao, K.D., Liu, D.Y., 2008. Geochronology, geochemistry and Hf–Sr–Nd isotopic compositions of Huziyan mafic xenoliths, southern Hunan Province, South China: petrogenesis and implications for lower crust evolution. Lithos 102, 65-87. DePaolo, D.J., 1981. Trace element and isotopic effects of combined wall rock assimilation and fractional crystallization. Earth and Planetary Science Letters 53, 189-202.

31

ACCEPTED MANUSCRIPT 32

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

IP

T

Defant, M.J., Kepezhinskas, P., 2001. Evidence suggests slab melting in arc magmas. EOS (Transactions, American

SC R

Geophysical Union) 82, 65-69.

Dickinson, W.R., 1975. Potash-depth (Kh) relations in continental margin and intra-oceanic magmatic arcs. Geology 3, 53-56.

NU

Dong, C.W., Zhang, D.R., Xu, X.S., Yan, Q., Zhu, G.Q., 2006. SHRIMP U–Pb dating and lithogeochemistry of

MA

basic-intermediate dike swarms from Jinjiang, Fujian Province. Acta Petrologica Sinica 22, 1696-1702 (in Chinese with English abstract).

D

Drummond, M.S., Defant, M.J., 1990. A model for trondhjemite–tonalite–dacite genesis and crustal growth via slab

TE

melting: Archean to modern comparisons. Journal of Geophysical Research–Solid Earth 95, 21503-21521.

641-644.

CE P

Eby, G.N., 1992. Chemical subdivision of the A-type granitoids: petrogenetic and tectonic implications. Geology 20,

AC

Elhlou, S., Belousova, E., Griffin, W.L., Pearson, N.J., O Reilly, S.Y., 2006. Trace element and isotopic composition of GJ-red zircon standard by laser ablation. Geochimica et Cosmochimica Acta 70, A158. Ferrari, O.M., Hochard, C., Stampfli, G.M., 2008. An alternative plate tectonic model for the Palaeozoic–Early Mesozoic Palaeo-tethyan evolution of southeast Asia (Northern Thailand–Burma). Tectonophysics 451, 346-365. Galer, S., Abouchami, W., 1998. Practical application of lead triple spiking for correction of instrumental mass discrimination. Mineralogical Magazine 62A, 491-492. Gao, J.F., Lu, J.J., Lai, M.Y., Lin, Y.P., Pu, W., 2003. Analysis of trace elements rock samples using HR–ICP–MS. Journal of Nanjing University (Natural Sciences) 39, 844-850 (in Chinese with English abstract).

32

ACCEPTED MANUSCRIPT 33

Gilder, S.A., Gill, J., Coe, R.S., Zhao, X., Liu, Z., Wang, G., Yuan, K., Liu, W., Kuang, G., Wu, H., 1996.Isotopic and paleomagnetic constraints on the Mesozoic tectonic evolution of south China. Journal of Geophysical Research:

IP

T

Solid Earth (1978–2012) 101, 16137-16154.

distribution of rifting in China. Tectonophysics 197, 225-243.

SC R

Gilder, S.A., Keller, G.R., Luo, M., Goodell, P.C., 1991. Eastern Asia and the western Pacific timing and spatial

Goldstein, S.L., O'Nions, R.K., Hamilton, P.J., 1984. A Sm–Nd isotopic study of atmospheric dusts and particulates from

NU

major river systems. Earth and Planetary Science Letters 70, 221-236.

MA

Griffin, W.L., Pearson, N.J., Belousova, E., Jackson, S.E., Van Achterbergh, E., O Reilly, S.Y., Shee, S.R., 2000. The Hf isotope composition of cratonic mantle: LA–MC–ICP-MS analysis of zircon megacrysts in kimberlites. Geochimica

D

et Cosmochimica Acta 64, 133-147.

TE

Griffin, W.L., Wang, X., Jackson, S.E., Pearson, N.J., O'Reilly, S.Y., Xu, X.S., Zhou, X.M., 2002. Zircon chemistry and

237-269.

CE P

magma mixing, SE China: in-situ analysis of Hf isotopes, Tonglu and Pingtan igneous complexes. Lithos 61,

AC

Guo, F., Fan, W.M., Li, C.W., Zhao, L., Li, H.X., Yang, J.H., 2012. Multi-stage crust–mantle interaction in SE China: Temporal, thermal and compositional constraints from the Mesozoic felsic volcanic rocks in eastern Guangdong–Fujian provinces. Lithos 150, 62-84. Hacker, B.R., Ratschbacher, L., Webb, L., Ireland, T., Walker, D., Shuwen, D., 1998. U/Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling–Dabie Orogen, China. Earth and Planetary Science Letters 161, 215-230. Hart, S.R., 1984. A large-scale isotope anomaly in the Southern Hemisphere mantle. Nature 309, 753-757. He, X.X., Zhu, X.K., Yang, C., Tang, S.H., 2005. High–precision analysis of Pb isotope ratios using MC–ICP–MS. Acta Geoscientica Sinica 26, 19-22 (in Chinese with English abstract).

33

ACCEPTED MANUSCRIPT 34

He, Z.Y., Xu, X.S., 2012. Petrogenesis of the Late Yanshanian mantle-derived intrusions in southeastern China: Response to the geodynamics of paleo-Pacific plate subduction. Chemical Geology 328, 208-221.

IP

T

He, Z.Y., Xu, X.S., Niu, Y.L., 2010.Petrogenesis and tectonic significance of a Mesozoic granite–syenite–gabbro

SC R

association from inland South China. Lithos 119, 621-641.

Hofmann, A.W., 2003. Sampling mantle heterogeneity through oceanic basalts: isotopes and trace elements. Treatise on Geochemistry 2, 61-101.

NU

Hofmann, A.W., Jochum, K.P., Seufert, M., White, W.M., 1986. Nb and Pb in oceanic basalts: new constraints on mantle

MA

evolution. Earth and Planetary Science Letters 79, 33–45.

Hou, K.J., Li, Y.H., Zou, T.R., Qu, X.M., Shi, Y.R., Xie, G.Q., 2007. Laser ablation MC–ICP–MS technique for Hf

TE

with English abstract).

D

isotope microanalysis of zircon and its geological applications. Acta Petrologica Sinica 23, 2595-2604 (in Chinese

CE P

Hu, G.R., Zhang, B.D., 1998. Neodymium isotope compositions and source materials of the meta-basement in Central Jiangxi Province. Acta Petrologica et Mineralogica 17, 35-40 (in Chinese with English abstract).

AC

Hu, X.M., Huang, Z.C., Wang, J.G., Yu, J.H., Xu, K.D., Jansa, L., Hu, W.X., 2012. Geology of the Fuding inlier in southeastern China: Implication for late Paleozoic Cathaysian paleogeography. Gondwana Research 22, 507-518. Huang, H.Q., Li, X.H., Li, W.X., Li, Z.X., 2011. Formation of high δ 18O fayalite-bearing A-type granite by high-temperature melting of granulitic metasedimentary rocks, southern China. Geology 39, 903–906. Huang, H.Q., Li, X.H., Li, Z.X., Li, W.X., 2013. Intraplate crustal remelting as the genesis of Jurassic high-K granites in the coastal region of the Guangdong Province, SE China. Journal of Asian Earth Sciences 74, 280–302. Jackson, S.E., Pearson, N.J., Griffin, W.L., Belousova, E.A., 2004. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pb zircon geochronology. Chemical Geology 211, 47-69. Jacobsen, S.B., Wasserburg, G.J., 1980. Sm–Nd isotopic evolution of chondrites. Earth and Planetary Science Letters 50,

34

ACCEPTED MANUSCRIPT 35

139-155. Jahn, B.M., Cornichet, J., Cong, B.L., Yui, T.F., 1996. Ultrahigh–εNd eclogites from an ultrahigh-pressure metamorphic

IP

T

terrane of China. Chemical Geology 127, 61-79.

SC R

Jahn, B.M., Wu, F.Y., Lo, C.H., Tsai, C.H., 1999. Crust–mantle interaction induced by deep subduction of the continental crust: geochemical and Sr–Nd isotopic evidence from post-collisional mafic–ultramafic intrusions of the northern Dabie complex, central China. Chemical Geology 157, 119-146.

NU

Jahn, B.M., Zhou, X.H., Li, J.L., 1990. Formation and tectonic evolution of southeastern China and Taiwan: isotopic and

MA

geochemical constraints. Tectonophysics 183, 145–160.

Jiang, Y.H., Jiang, S.Y., Dai, B.Z., Liao, S.Y., Zhao, K.D., Ling, H.F., 2009. Middle to late Jurassic felsic and mafic

D

magmatism in southern Hunan Province, southeast China: Implications for a continental arc to rifting. Lithos 107,

TE

185-204.

CE P

Jiang, Y.H., Jiang, S.Y., Ling, H.F., Dai, B.Z., 2006. Low-degree melting of a metasomatized lithospheric mantle for the origin of Cenozoic Yulong monzogranite-porphyry, east Tibet: geochemical and Sr–Nd–Pb–Hf isotopic constraints.

AC

Earth and Planetary Science Letters 241, 617-633. Kemp, A.I.S., Hawkesworth, C.J., Foster, G.L., Paterson, B.A., Woodhead, J.D., Hergt, J.M., Gray, C.M., Whitehouse, M.J., 2007. Magmatic and crustal differentiation history of granitic rocks from Hf-O isotopes in zircon. Science 315, 980–983. Kelemen, P.B., Hanghøj, K., Greene, A.R., 2003. One view of the geochemistry of subduction-related magmatic arcs, with an emphasis on primitive andesite and lower crust. Treatise on Geochemistry 3, 593-659. Kelemen, P.B., 1995. Genesis of high Mg-number andesites and the continental-crust. Contributions to Mineralogy and Petrology 120, 1-19. Klemme, S., Prowatke, S., Hametner, K., Günther, D., 2005. Partitioning of trace elements between rutile and silicate

35

ACCEPTED MANUSCRIPT 36

melts: implications for subduction zones. Geochimica et Cosmochimica Acta 69, 2361-2371. Lan, T.G., Fan, H.R., Hu, F.F., Tomkins, A.G., Yang, K.F., Liu, Y.S., 2011. Multiple crust–mantle interactions for the

IP

T

destruction of the North China Craton: Geochemical and Sr–Nd–Pb–Hf isotopic evidence from the Longbaoshan

SC R

alkaline complex. Lithos 122, 87-106.

Lepvrier, C., Faure, M., Van, V.N., Vu, T.V., Lin, W., Trong, T.T., Hoa, P.T., 2011. North-directed Triassic nappes in Northeastern Vietnam (East Bac Bo). Journal of Asian Earth Sciences 41, 56–68.

NU

Li, B., Zhao, K.D., Yang, S.Y., Dai, B.Z., 2013. Petrogenesis of the porphyritic dacite from Ermiaogou Cu–Au deposit in

MA

Zijinshan ore field and its metallogenetic implications. Acta Petrologica Sinica 29, 4167-4185 (in Chinese with English abstract).

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Li, J.H., Zhang, Y.Q., Dong, S.W., Johnston, S.T., 2014. Cretaceous tectonic evolution of South China: A preliminary

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synthesis. Earth-Science Reviews 134, 98-136.

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Li, J.W., Zhao, X.F., Zhou, M.F., Ma, C.Q., de Souza, Z.S., and Vasconcelos, P., 2009a, Late Mesozoic magmatism from the Daye region, eastern China: U–Pb ages, petrogenesis, and geodynamic implications: Contributions to

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Mineralogy and Petrology 157, 383-409. Li, X.H., 2000. Cretaceous magmatism and lithospheric extension in Southeast China. Journal of Asian Earth Sciences 18, 293-305.

Li, X.H., Chen, Z.G., Liu, D.Y., Li, W.X., 2003. Jurassic gabbro-granite-syenite suites from southern Jiangxi Province, SE China: age, origin, and tectonic significance. International Geology Review 45, 898–921. Li, X.H., Li, W.X., Li, Z.X., 2007a. On the genetic classification and tectonic implications of the Early Yanshanian granitoids in the Nanling Range, South China. Chinese Science Bulletin 52, 1873–1885.

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Li, X.H., Li, W.X., Li, Z.X., Lo, C.H., Wang, J., Ye, M.F., Yang, Y.H., 2009d. Amalgamation between the Yangtze and Cathaysia Blocks in South China: constraints from SHRIMP U–Pb zircon ages, geochemistry and Nd–Hf isotopes of

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the Shuangxiwu volcanic rocks. Precambrian Research 174, 117-128.

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Li, X.H., Li, W.X., Wang, X.C., Li, Q.L., Liu, Y., Tang, G.Q., 2009b. Role of mantle-derived magma in genesis of early Yanshanian granites in the Nanling Range, South China: in situ zircon Hf–O isotopic constraints. Science in China Series D: Earth Sciences 52, 1262–1278.

NU

Li, X.H., Li, Z.X., Li, W.X., 2014. Detrital zircon U-Pb age and Hf isotope constrains on the generation and reworking of

MA

Precambrian continental crust in the Cathaysia Block, South China: A synthesis. Gondwana Research 25, 1202-1215.

D

Li, X.H., Li, Z.X., Li, W.X., Liu, Y., Yuan, C., Wei, G.J., Qi, C.S., 2007b. U–Pb zircon, geochemical and Sr–Nd–Hf

TE

isotopic constraints on age and origin of Jurassic I-and A-type granites from central Guangdong, SE China: A major

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igneous event in response to foundering of a subducted flat-slab? Lithos 96, 186–204. Li, X.H., Li, Z.X., Li, W.X., Wang, Y., 2006. Initiation of the Indosinian Orogeny in South China: evidence for a

AC

Permian magmatic arc on Hainan Island. The Journal of geology 114, 341-353. Li, Z.X., Li, X.H., 2007. Formation of the 1300-km-wide intracontinental orogen and postorogenic magmatic province in Mesozoic South China: A flat-slab subduction model. Geology 35, 179–182. Li, Z.X., Li, X.H., Chung, S.L., Lo, C.H., Xu, X.S., Li, W.X., 2012. Magmatic switch-on and switch-off along the South China continental margin since the Permian: Transition from an Andean-type to a Western Pacific-type plate boundary. Tectonophysics 532, 271-290. Li, Z.X., Li, X.H., Kinny, P.D., Wang, J., 1999. The breakup of Rodinia: did it start with a mantle plume beneath South China? Earth and Planetary Science Letters 173, 171-181.

37

ACCEPTED MANUSCRIPT 38

Li, Z.X., Li, X.H., Wartho, J.A., Clark, C., Li, W.X., Zhang, C.L., Bao, C.M., 2010. Magmatic and metamorphic events during the early Paleozoic Wuyi–Yunkai orogeny, southeastern South China: New age constraints and

IP

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pressure-temperature conditions. Geological Society of America Bulletin 122, 772-793.

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Liégeois, J., Navez, J., Hertogen, J., Black, R., 1998. Contrasting origin of post-collisional high-K calc-alkaline and shoshonitic versus alkaline and peralkaline granitoids: the use of sliding normalization. Lithos 45, 1-28. Liew, T.C., Hofmann, A.W., 1988. Precambrian crustal components, plutonic associations, plate environment of the

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Hercynian Fold Belt of central Europe: indications from a Nd and Sr isotopic study. Contributions to Mineralogy

MA

and Petrology 98, 129-138.

Liu, L., Qiu, J.S., and Li, Z., 2013. Origin of mafic microgranular enclaves (MMEs) and their host quartz monzonites

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interaction. Lithos 160, 145-163.

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from the Muchen pluton in Zhejiang Province, Southeast China: Implications for magma mixing and crust-mantle

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Lu, Y.J., Kerrich, R., Mccuaig, T.C., Li, Z.X., Hart, C.J., Cawood, P.A., Hou, Z., Bagas, L., Cliff, J., Belousova, E.A., 2013. Geochemical, Sr–Nd–Pb, and Zircon Hf–O Isotopic Compositions of Eocene–Oligocene Shoshonitic and

AC

Potassic Adakite-like Felsic Intrusions in Western Yunnan, SW China: Petrogenesis and Tectonic Implications. Journal of Petrology 54, 1309-1348. Ludwig, K.R., 2003. User's manual for Isoplot 3.00: A geochronological toolkit for Microsoft Excel: Berkeley Geochronological Center, Special Publication No. 4a, p. 1–70. Lugmair, G.W., Marti, K., 1978. Lunar initial 143Nd/144Nd: Differential evolution of the lunar crust and mantle. Earth and Planetary Science Letters 39, 349-357. Ma, L., Jiang, S.Y., Dai, B.Z., Jiang, Y.H., Hou, M.L., Pu, W., Xu, B., 2013. Multiple sources for the origin of Late Jurassic Linglong adakitic granite in the Shandong Peninsula, eastern China: Zircon U–Pb geochronological, geochemical and Sr–Nd–Hf isotopic evidence. Lithos 162, 251-263.

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Macpherson, C.G., 2008. Lithosphere erosion and crustal growth in subduction zones: Insights from initiation of the nascent East Philippine Arc. Geology 36, 311-314.

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Macpherson, C.G., Dreher, S.T., Thirlwall, M.F., 2006. Adakites without slab melting: High pressure differentiation of

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island arc magma, Mindanao, the Philippines. Earth and Planetary Science Letters 243, 581-593. McDonough, W.F., Sun, S., 1995. The composition of the Earth. Chemical Geology 120, 223-253. Meng, L.F., Li, Z.X., Chen, H.L., Li, X.H., Wang, X.C., 2012. Geochronological and geochemical results from Mesozoic

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basalts in southern South China Block support the flat-slab subduction model. Lithos 132, 127-140.

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Metcalfe, I., 2002. Permian tectonic framework and palaeogeography of SE Asia. Journal of Asian Earth Sciences 20, 551-566.

87

Rb decay constant by age comparison against the U–Pb

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Nebel, O., Scherer, E.E., Mezger, K., 2011. Evaluation of the

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system. Earth and Planetary Science Letters 301, 1-8.

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Nielsen, R., 2006. Geochemical Earth Reference Model (GERM) partition coefficient (Kd) database. Nikolaeva, K., Gerya, T.V., Connolly, J.A.D., 2008. Numerical modelling of crustal growth in intraoceanic volcanic arcs.

AC

Physics of the Earth and Planetary Interiors 171, 336-356. Niu, Y.L., O'Hara, M.J., Pearce, J.A., 2003. Initiation of subduction zones as a consequence of lateral compositional buoyancy contrast within the lithosphere: a petrological perspective. Journal of Petrology 44, 851-866. Petford, N., Gallagher, K., 2001. Partial melting of mafic (amphibolitic) lower crust by periodic influx of basaltic magma. Earth and Planetary Science Letters 193, 483-499. Pu, W., Gao, J.F., Zhao, K.D., Ling, H.F., Jiang, S.Y., 2005. Separation method of Rb–Sr, Sm–Nd using DCTA and HIBA.Journal of Nanjing University (Natural Sciences) 41, 445-450 (in Chinese with English abstract). Rapp, R.P., Shimizu, N., Norman, M.D., Applegate, G.S., 1999. Reaction between slab-derived melts and peridotite in the mantle wedge: experimental constraints at 3.8 GPa. Chemical Geology 160, 335-356.

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Rapp, R.P., Watson, E.B., Miller, C.F., 1991. Partial melting of amphibolite/eclogite and the origin of Archean trondhjemites and tonalites. Precambrian Research, 51, 1-25.

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Roberts, M.P., Clemens, J.D., 1993. Origin of high-potassium, talc-alkaline, I-type granitoids. Geology 21, 825-828.

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Rudnick, R.L., Gao, S., 2003. Composition of the continental crust. Treatise on Geochemistry 3, 1-64. Sen, C., Dunn, T., 1994. Dehydration melting of a basaltic composition amphibolite at 1.5 and 2.0 GPa: implications for the origin of adakites. Contributions to Mineralogy and Petrology 117, 394-409.

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Shen, W.Z., Yu, J.H., Zhao, L., Chen, Z.L., Lin, H.C., 2003. Nd isotopic characteristics of post-Archean sediments from

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the Eastern Nanling Range: evidence for crustal evolution. Chinese Science Bulletin 48, 1679-1685. Shu, L.S., 2012. An analysis of principal features of tectonic evolution in South China Block. Geological Bulletin of

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China 31, 1035-1053 (in Chinese with English abstract).

176

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Söderlund, U., Patchett, P.J., Vervoort, J.D., Isachsen, C.E., 2004. The

Lu decay constant determined by Lu–Hf and

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U–Pb isotope systematics of Precambrian mafic intrusions. Earth and Planetary Science Letters 219, 311-324. Streckeisen, A., Le Maitre, R.W., 1979. A chemical approximation to the modal QAPF classification of the igneous

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rocks. Neues Jahrbuch für Mineralogie, Abhandlungen 136, 169-206. Sun, W.D., Ding, X., Hu, Y.H., Li, X.H., 2007. The golden transformation of the Cretaceous plate subduction in the west Pacific. Earth and Planetary Science Letters 262, 533-542. Wan, Y.S., Liu, D.Y., Xu, M.H., Zhuang, J.M., Song, B., Shi, Y.R., Du, L.L., 2007. SHRIMP U-Pb zircon geochronology and geochemistry of metavolcanic and metasedimentary rocks in Northwestern Fujian, Cathaysia block, China: Tectonic implications and the need to redefine lithostratigraphic units. Gondwana Research 12, 166-183.

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Wang, L.J., Griffin, W.L., Yu, J.H., O'Reilly, S.Y., 2013b. U-Pb and Lu-Hf isotopes in detrital zircon from Neoproterozoic sedimentary rocks in the northern Yangtze Block: Implications for Precambrian crustal evolution.

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Gondwana Research 23, 1261-1272.

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Wang, Q., Li, J.W., Jian, P., Zhao, Z.H., Xiong, X.L., Bao, Z.W., Xu, J.F., Li, C.F., Ma, J.L., 2005. Alkaline syenites in eastern Cathaysia (South China): link to Permian–Triassic transtension. Earth and Planetary Science Letters 230, 339-354.

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Wang, Q., Xu, J.F., Jian, P., Bao, Z.W., Zhao, Z.H., Li, C.F., Xiong, X.L., Ma, J.L., 2006. Petrogenesis of adakitic

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porphyries in an extensional tectonic setting, Dexing, South China: implications for the genesis of porphyry copper mineralization. Journal of Petrology 47, 119-144.

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Wang, X.L., Zhao, G.C., Zhou, J.C., Liu, Y.S., Hu, J., 2008b. Geochronology and Hf isotopes of zircon from volcanic

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rocks of the Shuangqiaoshan Group, South China: Implications for the Neoproterozoic tectonic evolution of the

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eastern Jiangnan orogen. Gondwana Research 14, 355-367. Wang, X.C., Li, X.H., Li, W.X., Li, Z.X., 2009. Variable involvements of mantle plumes in the genesis of

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mid-Neoproterozoic basaltic rocks in South China: a review. Gondwana Research 15, 381-395. Wang, Y.J, Fan, W.M, Cawood, P.A., Ji, S., Peng, T.P, Chen, X., 2007a. Indosinian high-strain deformation for the Yunkaidashan tectonic belt, south China: Kinematics and 40Ar/39Ar geochronological constraints. Tectonics 26, Wang, Y.J., Fan, W.M., Cawood, P.A., Li, S.Z., 2008a. Sr–Nd–Pb isotopic constraints on multiple mantle domains for Mesozoic mafic rocks beneath the South China Block hinterland. Lithos 106, 297-308. Wang, Y.J., Fan, W.M., Guo, F., Peng, T.P., Li, C.W., 2003. Geochemistry of Mesozoic mafic rocks adjacent to the Chenzhou-Linwu fault, South China: implications for the lithospheric boundary between the Yangtze and Cathaysia blocks. International Geology Review 45, 263-286.

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Wang, Y.J., Fan, W.M., Sun, M., Liang, X.Q., Zhang, Y.H., Peng, T.P., 2007b. Geochronological, geochemical and geothermal constraints on petrogenesis of the Indosinian peraluminous granites in the South China Block: a case

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study in the Hunan Province. Lithos 96, 475-502.

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Wang, Y.J., Fan, W.M., Zhang, G.W., Zhang, Y.H., 2013a. Phanerozoic tectonics of the South China Block: key observations and controversies. Gondwana Research 23, 1273-1305.

Wu, F.Y., Yang, Y.H., Xie, L.W., Yang, J.H., Xu, P., 2006. Hf isotopic compositions of the standard zircons and

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baddeleyites used in U–Pb geochronology. Chemical Geology 234, 105-126.

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Xie, X., Xu, X.S., Zou, H.B., Jiang, S.Y., Zhang, M., Qiu, J.S., 2006. Early J2 basalts in SE China: incipience of large-scale late Mesozoic magmatism. Science in China Series D: Earth Sciences 49, 796–815.

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Xiong, X.L., Adam, J., Green, T.H., 2005. Rutile stability and rutile/melt HFSE partitioning during partial melting of

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hydrous basalt: implications for TTG genesis. Chemical Geology 218, 339-359.

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Xu, X.B., Zhang, Y.Q., 2011. La-ICP-MS U–Pb and 40Ar/39Ar geochronology of the sheared metamorphic rocks in the Wuyishan: Constraints on the timing of Early Paleozoic and Early Mesozoic tectono-thermal events in SE China.

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Tectonophysics 501, 71-86.

Xu, X.B., Zhang, Y.Q., Jia, D., Shu, L.S., Wang, R.R., 2009. Early Mesozoic geotectonic processes in South China. Geology in China 36, 573-591 (in Chinese with English abstract). Xu, X.S., Dong, C.W., Li, W.X., Zhou, X.M., 1999. Late Mesozoic intrusive complexes in the coastal area of Fujian, SE China: the significance of the gabbro–diorite–granite association. Lithos 46, 299-315. Xu, X.S., O'Reilly, S.Y., Griffin, W.L., Wang, X.L., Pearson, N.J., He, Z.Y., 2007. The crust of Cathaysia: Age, assembly and reworking of two terranes. Precambrian Research 158, 51-78. Yang, Z.L., Sheng, W.Z., Tao, K.Y., Shen, J.L., 1999. Sr, Nd and Pb isotopic characteristics of early cretaceous basaltic rocks from the coast of Zhejiang and Fujian: evidence for ancient enriched mantle source. Scientia Geologica Sinica

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34, 59-68 (in Chinese with English abstract). Yao, J.L., Shu, L.S., Santosh, M., 2011. Detrital zircon U-Pb geochronology, Hf-isotopes and geochemistry-New clues

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for the Precambrian crustal evolution of Cathaysia Block, South China. Gondwana Research 20, 553-567.

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Yu, X.Q., Wu, G.G., Zhao, X.X., Zhang, D., Di, Y.J., Qiu, J.T., Dai, Y.P., Li, C.L., 2012. New geochronological data from the Paleozoic and Mesozoic nappe structures, igneous rocks, and molybdenite in the North Wuyi area, Southeast China. Gondwana Research 22, 519-533.

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Yu, X.Q., Wu, G.G., Zhao, X.X., Gao, J.F., Di, Y.J., Zheng, Y., Dai, Y.P., Li, C.L., Qiu, J.T., 2010. The Early Jurassic

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tectono-magmatic events in southern Jiangxi and northern Guangdong provinces, SE China: Constraints from the SHRIMP zircon U–Pb dating. Journal of Asian Earth Sciences 39, 408-422.

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Gondwana Research 23, 1241-1260.

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Zhang, S.B., Zheng, Y.F., 2013. Formation and evolution of Precambrian continental lithosphere in South China.

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Zhang, Y.Q., Xu, X.B., Jia, D., Shu, L.S., 2009. Deformation record of the change from Indosinian collision-related tectonic system to Yanshanian subduction-related tectonic system in South China during the Early Mesozoic. Earth

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Science Frontiers 16, 234-247 (in Chinese with English abstract). Zhang, Z.J, Wang, Y.H, 2007. Crustal structure and contact relationship revealed from deep seismic sounding data in South China. Physics of the Earth and Planetary Interiors 165, 114-126. Zhang, Z.J., Xu, T., Zhao, B., Badal, J., 2013. Systematic variations in seismic velocity and reflection in the crust of Cathaysia: New constraints on intraplate orogeny in the South China continent. Gondwana Research 24, 902-917. Zhou, X.M., Li, W.X., 2000. Origin of Late Mesozoic igneous rocks in Southeastern China: implications for lithosphere subduction and underplating of mafic magmas. Tectonophysics 326, 269-287. Zhou, X.M., Sun, T., Shen, W.Z., Shu, L.S., Niu, Y.L., 2006. Petrogenesis of Mesozoic granitoids and volcanic rocks in South China: A response to tectonic evolution. Episodes 29, 26-33.

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Zhu, W.G., Zhong, H., Li, X.H., He, D.F., Song, X.Y., Ren, T., Chen, Z.Q., Sun, H.S., Liao, J.Q., 2010. The early Jurassic mafic–ultramafic intrusion and A-type granite from northeastern Guangdong, SE China: age, origin, and

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tectonic significance. Lithos 119, 313-329.

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Figure captions

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Fig.1. Schematic geological map of South China showing the distribution of Triassic and Jurassic granitoid and volcanic

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rocks, modified after Chen et al. (2008), Guo et al. (2012), Li and Li (2007), Zhou et al. (2006). I- Jiangshan–Shaoxing fault; II- Pingxiang–Yushan fault; III- Zhenghe–Dapu fault; IV- Chenzhou–Linwu fault.

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Fig.2. (a) Map of the Central Cathaysia Block showing the locations of samples studied; (b) Simplified geological map of

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the Kuokeng granodiorite and granodiorite porphyry intrusions.

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Fig.3. (a) Photo of granodiorite; (b) Photo of granodiorite porphyry; (c) and (d) thin section microphotographs of

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representative granodiorite; (e) and (f) thin section microphotographs of representative granodiorite porphyry. These thin

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section microphotographs were taken using a Nikon microscope under cross-polarised light. (Kf = K-feldspar, Amp =

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amphibole, Bi = biotite, Qtz = quartz, Pl = plagioclase)

Fig.4. (a) Q′-ANOR classification diagram (Streckeisen and Le Maitre, 1979) for the granitoids, where Q′=100*Q/(Q+Or+Ab+An) and ANOR=100*An/(Or+An); (b) the total alkali vs. silica (TAS) diagram; (c) SiO2 vs. K2O diagram; (d) A/NK [molar ratio Al2O3/(Na2O + K2O)] vs. A/CNK [molar ratio Al2O3/(CaO+Na2O+K2O)] plot. The compositions of coeval mafic suites are cited from Wang et al. (2008) and Xie et al. (2006).

Fig. 5. Plots of TiO2 vs. SiO2 (a), Al2O3 vs. SiO2 (b), Fe2O3T vs. SiO2 (c), MgO vs.SiO2 (d), CaO vs. SiO2 (e), Na2O vs. SiO2 (f), P2O5 vs. SiO2 (g), V vs. SiO2 (h), Dy/Yb vs. SiO2 (i) for the samples.

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Fig. 6.(a) (Yb)N vs.( La/Yb)N diagram for the Kuokeng plutons and Pinghe dacites, showing the results of batch-melting modeling curves of lower crust and tholeiitic oceanic crust leaving garnet or amphibole in the residue, calculated by Li et

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al. (2009a). The four dashed curves represent melting leaving a restite of eclogite, amphibolite eclogite, 10% garnet

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amphibolite and garnet-free amphibolite, respectively, based on MORB as the starting composition. The melt percentage is shown next to the melting curves. The fields of adakites and low Al TTD are from Drummond and Defant (1990). TTD represents Trondhjemite–Tonalite–Dacite. (b) MgO (wt. %) vs SiO2 (wt. %). (c) Ni (ppm) vs. SiO2 (wt. %). (d) Cr (ppm)

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vs. SiO2 (wt. %). The field for adakites derived from slab melting is from Defant and Kepezhinskas (2001), for

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metabasaltic and eclogite experimental melts is from Rapp et al. (1999), for thick lower crust-derived adakite-like rocks and delaminated lower crust-derived adakite-like rocks are from Wang et al. (2006), and for metabasaltic and eclogite

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experimental melts hybridized by peridotite is from Rapp et al. (1999).

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Fig. 7. Chondrite-normalized REE patterns (a, c, e) and primitive mantle-normalized multi-element patterns (b, d, f). Shaded fields without outline are for coeval mafic rocks in Cathaysia Block (Wang et al., 2008a). Dashed line fields are

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for Triassic aegirite-augite syenite in western Fujian Province (Wang et al., 2005). Red lines are for the average of Andean basalts (Kelemen et al., 2003). Chondrite normalization values are from Boynton (1984), primitive mantle normalization values are from McDonough and Sun (1995).

Fig. 8. La/Yb vs. La (a) and La/Sm vs. La (b) diagrams for the studied rocks and coeval basaltic rocks in Cathaysia Block. Data for the Jurassic basaltic rocks of Cathaysia Block are cited from Wang et al. (2008) and Xie et al. (2006); Vector arrows show the effect of increasing degrees of partial melting and fractionation. Hf/Sm vs. Sr/Y (c) and Zr/Y (d) plots of the studied rocks for constraining the possible residual assemblage during melting. The partition coefficients of Sr, Y, Zr, Hf and Sm for garnet, hornblende, plagioclase and zircon are compiled from the GERM Partition Coefficient (Kd)

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Database (website: http://earthref.org/cgi-bin/er.cgi). Values of the average LCC (lower continental crust) are from

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Rudnick and Gao (2003).

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Sr/86Sr vs. εNd (t) diagrams for these

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Fig. 9. (a) Age vs. εNd(t) values plot for syenite-granodiorites and (b) Initial

intrusions. Reference data sources: Line A represents the Proterozoic crustal end member of higher degree of maturation in the Cathaysia Block, with average isotopic compositions of

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Sm/144Nd=0.1132 and

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Nd/144Nd=0.511568 (Shen et

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Pb/204Pb vs.

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Pb/204Pb (c) and

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Sm/144Nd=0.1087 and

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Nd/144Nd=0.512052 (Hu and Zhang, 1998). Initial

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with average isotopic compositions of

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al., 2003); line B represents the Proterozoic crustal end member of lower degree of maturation in the Cathaysia Block,

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Pb/204Pb vs.

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Pb/204Pb (d) diagrams for these intrusions. Data sources: coeval

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granitoids and basalts rocks in the Cathaysia Block (Xie et al., 2006; Wang et al., 2008a; Huang et al., 2013);

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Middle-Late Jurassic crust-derived suites (Li et al., 2013); I-MORB (Indian MORB), P&N-MORB (Pacific and Atlantic

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MORB), OIB, NHRL and 4.55 Ga geochron (Barry and Kent, 1998; Hart 1984; Hofmann, 2003). A detailed simulation using Nd and Sr isotopes are calculated binary mixing curves between possible mafic and silicic magma end-members:

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one from depleted garnet-facies mantle (DM) and the other from the pure crustal rock-derived melts (Fig. 9b). Lithospheric mantle is represented by the Yangfang aegirine–augite syenite in western Fujian Province (Wang et al., 2005). The crustal end-member is represented by the Darongshan S-type granite (Liu et al., 2013).

Fig. 10. LA–ICP–MS zircon U–Pb concordia diagrams and CL images of representative zircon grains for granodiorite (a) and (b), and granodiorite porphyry (c) from the Cathaysia Block.

Fig. 11. Histograms of εHf(t) values for zircons from the Dafengnao syenite (a), Kuokeng granodiorite (b), Kuokeng granodiorite porphyry (c), inherited zircons of Kuokeng granodiorite and granodiorite porphyry (d), and Pinghe dacite (e).

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The enriched mantle “composition” is represented by the Yangfang aegirite-augite syenite in western Fujian Province

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(Wang et al., 2005).

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Fig. 12. (a) Diagram of εHf(t) vs. U–Pb ages for zircons from the intrusions and volcanics with the shaded field indicating Hf isotope evolution for Cathaysia crustal basement (Xu et al., 2007; He and Xu, 2012).

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Fig. 13. R1–R2 diagram of Batchelor and Bowden (1985) for the samples. The dacite and granodiorite samples fall into the

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pre-plate collision field; granodiorite porphyry samples fall into the pre-plate collision and post-collision uplift fields;

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syenite fall into the late orogenic field. R1 = 4Si-11(Na + K) - 2(Fe + Ti); R2 = 6Ca + 2 Mg + Al.

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Fig. 14. Cartoon illustrating the petrogenesis of the Jurassic syenite–granodiorites–dacite association in the Cathaysia

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Block. Andean-type subductions can lead to subduction nucleation at a passive margin, lithospheric extension and spatially discrete and localized intraplate asthenospheric upwelling, decompression melting, and underplating basaltic

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magmas parental to the gabbros and syenites at the back-arc.

Table captions

Table 1. Lithology, mineralogy and ages of the studied rocks

Table 2. Major element (wt.%) and trace element (ppm) concentrations and calculated zircon saturation temperatures of the studied rocks in South China.

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Table 3. Sr, Nd and Pb isotopic compositions of the studied rocks in South China.

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Supplemental Table 1. U-Pb isotopic compositions of zircons from the studied rocks in South China

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Supplemental Table 2. Hf isotopic compositions of zircons from the studied rocks in South China.

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Table 1 Lithology, mineralogy and ages of the studied rocks Sampl

Age Lithology

Mineralogy

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e

Dafeng

IP

n

Texture

Porphyritic-like texture， DFN01

Syenite

nao

middle-grained

e+Ep+Ap

Kuoken

NU

GT-03 g

Pe+Mc+Qtz+Fe-Tioxid

SC R

Locatio

Porphyritic-like texture, fine Granodiorite to middle-grained

(Ma) 165.5± 1.0

He et al., 2010

164.1± 1.8 This study

a+Ap+Zr

MA

GT-32

Pl+Kf+Qtz+Am+Bi+M

References

164.9± 2.1

Kuoken

GT-11-

Granodiorite

1

porphyry

D

Porphyritic-like texture, Pl+Kf+Qtz+Am+Bi+M

159.0±

TE

fine-grained granitic texture

g

This study a+Ap+Zr

1.4

08JH-2 Pinghe

CE P

for groundmass Porphyritic-like or

Dacite

165.0±

Guo et al.,

Pl+Kf+Qtz+Am+Bi

texture

1.0

2012

AC

12

rhyolitic

Mineral: Pl = Plagioclase, Kfs = K-feldspar, Qtz = Quartz, Bi = Biotite, Am = Amphibole, Ep = epidote, Pe = perthite, Mc = microcline, Ma = Magnetite, Ap = apatite, Zr = zircom, Ms = muscovite.

50

ACCEPTED MANUSCRIPT 51

Table 2 Major element (wt.%) and trace element (ppm) concentrations and zircon saturation temperatures of the studied felsic rocks in South China. DFN01a

Locality

Quannan

Latitude

N24°55′28″

Longtitude

DFN02a

GT-03

GT-27-1

GT-27-2

GT-32

Gt-09

Gt-10

GT-11-1

GT-11-2

GT-11-3

Guokeng

Guokeng

Guokeng

Guokeng

Guokeng

GDP

GDP

GDP

GDP

Liancheng

N24°55′21″

N25°43′35″

N25°43′41″

E114°25′46″

E114°26′18″

E116°57′32″

Dafengnao

Dafengnao

Guokeng

Guokeng

Guokeng

Guokeng

Lithology

S

S

GD

GD

GD

GD

GDP

Age (Ma)

165.5

164.9

159.0

SiO2

64.11

64.51

67.19

67.99

67.51

67.00

64.37

64.05

65.00

65.64

65.52

TiO2

0.37

0.31

0.42

0.40

0.42

0.47

0.69

0.67

0.53

0.49

0.51

Al2O3

15.21

15.06

15.04

15.59

15.56

15.95

16.78

16.27

15.89

15.65

15.64

5.54

5.48

Fe2O3

1.16

0.73

1.29

1.17

1.39

1.48

1.09

0.71

1.14

FeO

2.86

2.27

2.05

2.23

2.57

2.57

2.51

2.68

2.42

0.05

0.05

0.10

0.10

0.06

0.05

0.05

1.45

1.41

1.95

1.99

1.65

1.69

1.72

T

Fe2O3

0.12

0.13

0.06

0.06

MgO

0.14

0.12

1.54

1.21 3.29

CaO

1.88

1.94

3.24

Na2O

4.94

5.16

3.28

K 2O

6.06

5.85

3.56

P2O5

0.04

0.04

0.25

LOI

1.96

1.83

1.75

TOTAL

99.81

99.90

Mg#

4.76

A/CNK

0.84

CR

3.49

3.21

3.77

3.04

3.56

3.86

3.44

3.48

3.67

3.42

4.28

3.76

3.35

3.69

3.34

3.72

3.30

3.72

2.94

3.99

3.91

3.30

3.81

0.19

0.20

0.21

0.29

0.27

0.22

0.21

0.22

1.51

1.09

1.29

1.26

2.26

2.15

2.28

1.86

100.35

100.43

100.08

100.13

100.38

100.45

99.92

100.25

99.67

4.16

41.27

42.44

44.58

43.35

47.61

47.59

45.72

47.57

47.08

0.82

0.99

0.99

0.98

1.03

0.98

1.02

0.98

0.94

0.99

Li

21.2

17.7

20.6

26.6

23.8

23.2

24.4

25.9

21.8

Be

1.80

1.85

2.09

1.71

2.02

1.59

1.85

2.56

2.07

Sc

AC

CE P

MnO

US

164.1

IP

E116°57′32″

TE D

Sute

T

Liancheng

MA N

Sample

5.73

6.43

6.51

5.48

6.83

6.11

7.15

6.64

7.41

Ti

2218

1858

2052

2951

3144

2283

3342

3120

3537

3291

3419

V

7.66

6.49

51.1

65.2

66.8

60.3

78.3

77.2

79.6

76.9

79.5

Cr

27.6

22.1

21.1

10.3

7.45

18.4

10.7

11.5

9.27

9.58

12.6 51

ACCEPTED MANUSCRIPT Ni

11.5

10.5

9.50

3.79

3.86

9.47

5.51

6.30

5.01

4.94

5.79

Ga

36.7

37.1

15.7

20.5

20.9

17.6

19.7

17.4

20.0

21.7

19.6

Rb

103

95.4

100

108

86.4

103

117

126

120

109

112

Sr

46.1

56.8

438

445

454

489

Y

14.3

17.7

14.7

14.5

13.3

16.8

T

52

Zr

138

225

195

175

194

169

Nb

29

25.8

18.2

15.5

16.8

Mo

0.89

1.22

0.63

Cd

0.24

0.13

0.11

Sn

2.69

2.10

2.11

Cs

1.71

1.27

478

589

614

629

14.4

12.7

12.6

11.7

171

177

175

181

151

14.5

12.9

12.0

13.6

12.8

13.4

11.8

1.18

2.48

0.83

0.33

1.08

0.23

0.14

0.22

0.13

0.11

0.09

1.71

2.14

1.31

2.62

2.23

2.39

1.35

1.86

1.95

2.50

1.96

1.60

1.72

MA N

US

CR

IP

577

12.9

177

176

727

860

728

685

1024

922

1000

1058

1115

La

26.3

32.9

39.1

37.6

22.7

45.2

34.2

34.8

38.3

30.1

33.5

Ce

54.2

68.8

87.3

68.4

45.4

81.6

64.5

64.2

72.2

56.6

65.0

Pr

6.81

8.85

10.3

7.35

5.31

8.69

6.97

7.23

7.30

6.26

7.09

Nd

26.7

32.6

39.3

28.0

21.7

29.7

25.8

26.5

27.0

22.6

26.9

Sm

5.41

6.45

5.80

4.71

4.07

4.61

4.36

4.40

4.54

3.92

4.56

Eu

1.29

1.48

1.27

1.20

1.06

1.09

1.21

1.12

1.24

1.11

1.36

Gd

4.53

5.35

3.49

3.60

3.16

3.36

3.27

3.09

3.50

3.12

3.39

Tb

0.54

0.68

0.44

0.43

0.40

0.47

0.40

0.39

0.42

0.37

0.41

Dy

3.49

4.29

2.35

2.86

2.60

2.74

2.47

2.15

2.65

2.49

2.60

Ho

0.67

0.83

0.46

0.59

0.54

0.54

0.50

0.47

0.51

0.51

0.53

Er

1.87

2.31

1.31

1.67

1.54

1.64

1.40

1.24

1.49

1.39

1.49

Tm

0.26

0.31

0.21

0.25

0.23

0.23

0.20

0.17

0.21

0.19

0.21

Yb

1.75

2.05

1.41

1.53

1.46

1.64

1.31

1.29

1.32

1.30

1.32

Lu

0.31

0.35

0.23

0.28

0.26

0.24

0.21

0.20

0.22

0.21

0.22

Hf

3.61

4.43

4.91

4.67

4.76

4.09

4.35

4.30

4.43

4.43

4.26

Ta

1.84

1.59

1.19

1.31

1.50

1.28

1.03

0.93

1.00

1.02

1.16

11.0

2.20

4.44

12.1

7.66

2.65

15.0

5.19

7.77

23.7

14.7

13.5

16.9

13.4

16.4

12.4

10.4

14.6

W Pb

13.9

36.7

AC

CE P

TE D

Ba

52

ACCEPTED MANUSCRIPT 53

3.96

3.63

11.4

13.3

7.86

5.72

8.61

4.10

10.1

10.9

9.29

U

1.15

0.89

6.51

8.04

3.64

2.42

4.41

2.41

3.04

8.94

3.24

∑REE

134

167

193

158

110

182

147

147

161

130

149

TZr

734

771

790

781

787

781

771

779

776

774

765

08JH-212b

Locality

Pinghe

Latitude

N24°05′21″

08JH-214

Douling

Lithology

D

D

D

Age (Ma)

165.0

SiO2

63.44

63.13

62.85

TiO2

0.72

0.71

0.72

Al2O3

17.27

17.04

17.03

5.70

6.03

5.62

MnO

0.09

0.10

0.15

MgO

1.67

1.69

1.62

CaO

5.73

6.00

5.92

Na2O

2.20

1.85

2.58

K2O

1.70

1.86

2.30

P2O5

0.21

0.20

0.22

LOI

1.06

1.16

0.79

TOTAL

99.79

99.79

99.78

Mg#

36.69

35.72

36.27

A/CNK

1.09

1.07

0.97

Fe2O3

Fe2O3 FeO

TE D

Douling

MA N

E117°05′18″ Douling

T

b

CE P

Suite

b

AC

Longtitude

08JH-213

US

Sample

CR

IP

T

Th

Li 53

ACCEPTED MANUSCRIPT 54

Ti

4308

4281

4325

V

116

110

109

Cr

166

155

124

Ni

13.3

13.8

10.0

Ga

21.4

21.0

20.3

Rb

124

117

155

Sr

640

597

601

Y

19.0

18.1

16.8

Zr

115

106

93

Nb

11.2

10.8

10.9

Ba

382

531

433

La

30.6

28.6

28.7

Ce

57.0

54.4

54.3

Pr

6.51

6.35

6.33

Nd

25.3

25.0

24.7

Sm

4.64

4.69

4.54

Eu

1.49

1.44

1.22

Gd

4.06

4.02

3.99

Tb

0.56

0.59

0.53

Dy

3.37

3.40

3.28

Ho

0.67

0.63

0.58

Er

2.04

1.73

1.78

Tm

0.26

0.25

0.23

Yb

1.77

1.61

1.59

IP

9.1

CR

9.1

US

11.2

MA N

Sc

T

Be

Mo

TE D

Cd Sn

AC

CE P

Cs

54

ACCEPTED MANUSCRIPT 55

Lu

0.25

0.24

0.23

Hf

3.03

2.77

2.59

Ta

1.14

1.24

1.03

Th

9.41

8.98

8.91

U

3.17

3.31

2.81

∑REE

138

133

132

TZr

751

743

721

T

W

US

CR

IP

Pb

AC

CE P

TE D

from aHe et al. (2010); bGuo et al. (2012); other samples are from this study.

MA N

Note: S, syenite; GD, granodiorite; GDP, granodiorite porphyry; D, dacite; MG, monzogranite; LOI, loss of ignition; Mg# = MgO/(MgO+FeOT)*100 in atomic ratios. Data

55

ACCEPTED MANUSCRIPT 56

Table 3 Sr, Nd and Pb isotopic compositions of the studied rocks in South China. Sample

DFN01

No.

a

GT-03

GT-27-

GT-27-

GT-32-

1

2

1

Lithology

S

GD

GD

GD

t(Ma)

166

164

164

Rb(ppm)

95.4

100

Sr(ppm)

56.8

GDP

159

159

159

126

120

109

112

478

589

614

629

0.7627

0.5909

0.5134

0.5138

0.71085

0.71077

0.71078

0.71059

108

86.4

103

117

438

445

454

489

577

4.8664

0.6607

0.6997

0.5503

0.6092

0.5848

0.72372

0.71066

0.71039

0.71015

0.71039

2

7

0.00000

0.00000

1

8

9

7

7

0.71245

0.70915

0.70879

0.70889

9

1

3

3

Sm(ppm)

6.45

5.80

4.71

4.07

Nd(ppm)

32.6

39.3

28.0

0.1195

0.0891

0.51266

0.51188

2

4

3

9

0.00000

0.00000

0.00000

0.00000

7

8

7

7

5

0.70900

0.70853

0.70916

0.70946

0.70964

0.70946

4

4

1

3

5

0

4.61

4.36

4.40

4.54

3.92

4.56

21.7

29.7

25.8

26.5

27.0

22.6

26.9

0.1016

0.1133

0.0938

0.1022

0.1002

0.1017

0.1050

0.1023

0.51206

0.51211

0.51202

0.51214

0.51210

0.51207

0.51208

0.51206

MA

1

8

4

8

1

5

2

5

4

0.00001

0.00000

0.00001

0.00000

0.00001

0.00000

0.00000

0.00001

0.00000

2

1

7

3

5

3

6

7

0

5

εNd(t)

2.2

-12.5

-9.1

-8.5

-9.7

-7.8

-8.4

-9.1

-8.9

-9.3

TDM1(Ga)

0.78

1.55

1.47

1.57

1.42

1.38

1.40

1.46

1.49

1.48

TDM2(Ga)

0.78

1.97

1.70

1.64

1.74

1.58

1.63

1.69

1.67

1.70

17.541

17.583

17.797

17.796

17.645

15.589

15.591

15.601

15.597

15.597

38.220

38.184

38.335

38.316

38.103

206

204

( Pb/ P b)i (207Pb/204P b)i (208Pb/204P b)i

CE P

2sm

TE

6 0.00001

AC

d

D

d

IP

1

0.00000

144

Sm/ N

0.70983

NU

3

T

159

0.00000

Nd/144N

GDP

159

2

143

GDP

164

0.00000

147

3

164

5

Isr

2

GDP

0.00001

2sm

1

GDP

Rb/ Sr Sr/86Sr

GT-11-

GD

86

87

GT-11-

GT-10

SC R

87

GT-11-

GT-09

Note: S, syenite; GD, granodiorite; GDP, granodiorite porphyry. Data from aHe et al. (2010); other samples are from this study.

56

ACCEPTED MANUSCRIPT

AC

Figure 1

CE P

TE

D

MA

NU

SC R

IP

T

57

57

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

58

Figure 2

58

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

59

Figure 3

59

ACCEPTED MANUSCRIPT

CE P

AC

Figure 4

TE

D

MA

NU

SC R

IP

T

60

60

ACCEPTED MANUSCRIPT

CE P

AC

Figure 5

TE

D

MA

NU

SC R

IP

T

61

61

ACCEPTED MANUSCRIPT

TE

D

MA

NU

SC R

IP

T

62

AC

CE P

Figure 6

62

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

63

Figure 7

63

ACCEPTED MANUSCRIPT

AC

Figure 8

CE P

TE

D

MA

NU

SC R

IP

T

64

64

ACCEPTED MANUSCRIPT

AC

Figure 9

CE P

TE

D

MA

NU

SC R

IP

T

65

65

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

66

Figure 10

66

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

67

Figure 11

67

ACCEPTED MANUSCRIPT

SC R

IP

T

68

AC

CE P

TE

D

MA

NU

Figure 12

68

ACCEPTED MANUSCRIPT

NU

SC R

IP

T

69

AC

CE P

TE

D

MA

Figure 13

69

ACCEPTED MANUSCRIPT

MA

NU

SC R

IP

T

70

AC

CE P

TE

D

Figure 14

70

ACCEPTED MANUSCRIPT

SC R

IP

T

71

AC

CE P

TE

D

MA

NU

Graphical abstract

71

ACCEPTED MANUSCRIPT 72

Research Highlights:

SC R

IP

T

The Jurassic syenite–granodiorites–dacite in South China related to an Andean-type subduction.

Syenite derived from partial melting of lithosphere mantle with minor crustal materials.

AC

CE P

TE

D

MA

NU

Granodiorite and dacite originated from mafic lower crust or subduction-modified mantle sources.

72