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Geochronology and geochemistry of the Shilu Cu–Mo deposit in the Yunkai area, Guangdong Province, South China and its implication
Wei Zheng, Jing-wen Mao, Franco Pirajno, Hai-jie Zhao, Cai-sheng Zhao, Zhi-hao Mao, Yong-jian Wang
PII: S0169-1368(14)00365-5 DOI: doi: 10.1016/j.oregeorev.2014.12.009 Reference: OREGEO 1405
To appear in: Ore Geology Reviews
Received date: 4 December 2014 Accepted date: 11 December 2014
Please cite this article as: Zheng, Wei, Mao, Jing-wen, Pirajno, Franco, Zhao, Hai-jie, Zhao, Cai-sheng, Mao, Zhi-hao, Wang, Yong-jian, Geochronology and geochemistry of the Shilu Cu–Mo deposit in the Yunkai area, Guangdong Province, South China and its implication, Ore Geology Reviews (2014), doi: 10.1016/j.oregeorev.2014.12.009
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Geochronology and geochemistry of the Shilu Cu–Mo deposit in the Yunkai area,
Guangdong Province, South China and its implication
Wei Zheng a*, Jing-wen Mao b, Franco Pirajno c, Hai-jie Zhao b, Cai-sheng Zhao d, Zhi-hao
Mao a, Yong-jian Wang e a School of the Earth Science and Mineral Resources, China University of Geosciences,
Beijing 100083, China b MLR Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources,
Chinese Academy of Geological Sciences, Beijing 100037, China c Centre for Exploration Targeting, University of Western Australia, 35 Stirling Highway,
Crawley WA 6008, Australia d Technology and International Cooperation Department, Ministry of Land and Resources,
Beijing 100812, China e CNNC Beijing Research Institute of Uranium Geology, Beijing 100029, China
*Corresponding author: Tel. +86-18810553516. Email address: [email protected]
(Zheng Wei) ACCEPTED MANUSCRIPT
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ABSTRACT
Shilu is a large porphyry-skarn deposit in the Yunkai district in Guangdong Province,
South China. The Shilu granitic intrusion in the mine area is a granodiorite which is genetically related to Cu mineralization. Plagioclase in the granodiorite has a zoned texture and is mainly andesine with minor amounts of labradorite, whereas the K-feldspars exhibit
Carlsbad twins and some are also characterized by a zonal texture. K-feldspars from the granodiorite show high contents of Or (87–92 wt%) with minor Ab (8–13 wt%) and negligible An value of 0–0.3 wt%. Biotite can be classified as magnesio-biotite, and is characterized by Mg-rich [Mg/(Mg + Fe) = 0.54-0.60] and AlVI-low (average values = 0.11).
Hornblende is chiefly magnesiohornblende and tschermakite. LA–ICP–MS zircon U–Pb age of the Shilu granodiorite is 107±0.7 Ma, which is consistent with molybdenites Re–Os age of
104.1±1.3 Ma. Geochemical data indicate that the Shilu granodiorite is silica-rich (SiO2 =
63.43–65.03 wt%) and alkali-rich (K2O + Na2O = 5.45–6.05 wt%), as well as calcium-rich
(CaO = 4.76–5.1 wt%). Trace element geochemistry results show enrichments in large ion lithophile elements (e.g., Rb, K, and Ba) and depletions in some high field strength elements
(e.g., Nb, P, Ta, andACCEPTED Ti). The total rare earth MANUSCRIPTelement (REE) content of the granodioritic rocks is low (∑REE < 200 ppm), and is characterized by light REE enrichment [(La/Yb)N > 9] and moderately negative Eu anomalies (Eu/Eu* = 0.83–0.90). These mineralogical, geochronological, and geochemical results suggest that the Shilu granodiorite has a mixed crust-mantle source with a geochemical affinity to I-type granitoids. Hornblende thermobarometry yielded magmatic crystallization temperatures of 686–785ºC and crystallization pressures between 1.0 and 2.34 kbar, which is converted to depths in a range of
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3.31 to 7.71 km. Biotite thermobarometry yielded similar temperatures and lower pressures of
680–780ºC and 0.8–2 kbar (depth 2.64–6.6 km), respectively. The parent magma had a high
87 86 oxygen fugacity. The Shilu granodiorite has a relatively low εNd/t-t value and high ( Sr/ Sr)i value, and Nd isotopes yield two-stage depleted mantle Nd model ages of 969–1590 Ma. Our new data, combined with previous studies, imply that the granodiorite and the associated
Shilu Cu–Mo deposit was formed in an extensional environment, closely related to remelting of residual subducted slab fragments in the Jurassic.
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Keywords: Shilu Cu–Mo deposit, Mineral chemistry, LA–ICP–MS zircon U–Pb dating,
Yunkai area, South China
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1. Introduction
Porphyry-skarn copper deposits are an economically important copper resource supplying about 75% of the world’s copper (Sillitoe, 2010). Such deposits form above subduction zones and are preferentially associated with calc-alkaline magmas (Cooke et al.,
2005; Sillitoe, 2010). Numerous porphyry-skarn copper deposits occur in eastern China along a NE–SW trending belt. Previous studies indicate that China’s Mesozoic porphyry-skarn copper deposits formed mainly in two periods: 180–135 Ma and 125–90 Ma (Mao et al., 2011,
2013, 2014) (Fig. 1a). The Shilu copper deposit is a typical porphyry-skarn copper deposit located in the Yangchun basin of western Guangdong province, China. Previous studies mainly focused on the geological characteristics of the Shilu Cu–Mo deposit (Yu et al., 1988;
Sun et al., 2008; Zhang et al., 2008; Zhao et al., 2012), but little research has been conducted on geochemical characteristics of the Shilu intrusion (Ma et al., 1985; Li et al., 2000). In addition, there is controversy over the timing of the granodioritic intrusion in this deposit.
Three ages, 122 Ma (Rb–Sr), 126 Ma (U–Pb), and 99–101 Ma (40Ar–39Ar), have been reported for the granodiorite (Yu et al., 1988). Moreover, the mineralogical characteristics, physical and chemicalACCEPTED conditions, source, tectonicMANUSCRIPT environment and evolution of the Shilu granodiorite rocks are still not very clear.
Herein, we present a systematic mineralogical, precise LA–ICP–MS zircon U–Pb geochronological, and geochemical study of the Shilu intrusion. We use these data to constrain the timing, petrogenesis, and tectonic setting of magmatism of the Shilu Cu–Mo deposit, which in turn enhances our understanding of the dynamics of Mesozoic magmatism in the Yangchun basin of western Guangdong province.
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2 Regional geology
The Yunkai (Fig. 1b) is an important tungsten–tin–copper and polymetallic metallogenic area of South China. Several intense magmatic events and related mineralization have been recognized (Cai et al., 2002). Recent exploration work indicates that Mesozoic rift basins controlled the distribution of mineralization, and that the majority of the ore deposits are located in and around Cretaceous or Cretaceous–Tertiary basins, including the Luoding,
Huaiji, and Yangchun basins (Mao et al., 2011a, b).
Yangchun is a NE–SW-trending fault-bounded basin with a sequence of Triassic rocks forming a synclinorium (Li et al., 2000). The Yangchun basin is located in the southwest of
South China fold belt (Ren et al., 1990), at the junction of Yunkai block and central Guangdong block (Fig.1b). Bounded by Wuchuan–Sihui fault, the northwest of
Yangchun basin is the Yunkai ancient uplift zone in which thick flysch and flyschoid sediments accumulated from Sinian to Cambrian, forming the basement of the region. The
Caledonian orogenic movement and associated regional metamorphism gave rise to the formation of greenschistACCEPTED facies–amphibolite MANUSCRIPT facies metamorphic rocks, and the formation of migmatites in some localities of the area (Zhang et al., 1993). Since the Caledonian, the
Yangchun basin experienced several tectonic movements, related to Indo-China, Yanshan,
Himalayan tectonics with dominant NE–NNE trending structures. Cai et al. (2001; 2002) believed that the Mesozoic lithosphere in western Guangdong experienced three stages of tectonic evolution, namely, collision and compression (224–265 Ma), transition from compression to extension (154–163 Ma) and finally extension (80–120 Ma). The complex
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structural features in the area, provide suitable channel ways for the emplacement of endogenic polymetallic deposits. So far, more than 50 deposits have been found in the basin and surrounding areas, including the Shilu Cu–Mo deposit, the Mange’ling Cu–Fe deposit, the Yingwuling W–Sn polymetallic deposit, and the Chadi Pb–Zn deposit.
3 Ore deposit geology
Shilu (111°38'37"E, 22°10'22"N) is a porphyry-skarn Cu–Mo deposit with average grades of 0.91% Cu, 0.21% Mo, 12.52 g/t Ag, 11.20% TFe, and 2.33% S (tonnage information not available at the time of writing). The stratigraphic sequence in the Shilu mine area comprises Carboniferous rocks and Quaternary sediments (Fig. 1c). The Carboniferous rocks are widespread in the south, east, and southwest of the Shilu basin and mainly comprise limestone and arenaceous shale. The principal structures in the mine area consist of NE- to
NNE-trending compressional faults and inferred NW- to NNW-trending transtensional faults
(Sun et al., 2008). The Shilu granodiorite is closely related to the mineralization and distributed in the north and center of the mine area. The NE- and SE-trending granodioritic intrusion has an ACCEPTED irregular ellipsoidal shape MANUSCRIPT with an outcrop area of 4.7 km2, and intrudes middle–upper Carboniferous dolomite and dolomitic limestone (Fig. 1c). In cross section the intrusion is a nearly vertical cylinder with a high angle contact with the country rocks, but locally the granodiorite contacts with the country rocks exhibit irregular shapes (Fig. 1c).
Cu–Mo orebodies are hosted in skarn and adjacent marble, distributed discontinuously around the Shilu granodiorite intrusion in the shape of an irregular band. Dioritic enclaves are commonly found in the Shilu granodiorite intrusion. They are mainly composed of
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plagioclase, K-feldspar, quartz, biotite, and hornblende, with much higher proportion of plagioclase than K-feldspar (Ma et al., 1985). The Shilu granodiorite (Fig. 2) is composed of plagioclase (45– 55%), K-feldspar (~20%), quartz (~20%), biotite (5–8%) and hornblende
(~5%) and accessory minerals (~1%) of magnetite, titanite, apatite, zircon, and allanite.
4 Samples and analytical techniques
Eight representative samples of the Shilu granodiorite were collected for geochemical analyses, and four samples for Sr–Nd isotopic analyses. LA– ICP–MS zircon U–Pb dating was carried out on a fresh granodiorite sample (SLH). The sampling location is shown in Fig.
1c. In some samples, rock-forming minerals show with various degrees of alteration, including chloritization of hornblende and biotite, sericitization of plagioclase.
The preparation of samples for zircon dating and whole-rock geochemistry was conducted in the Laboratory of the Institute of Geology and Mineral Resources, Langfang,
Hebei Province, China. An ultraclean ball mill was used to grind whole-rock samples to 200 mesh.
CathodoluminescenceACCEPTED (CL) images were MANUSCRIPT taken for the zircons prior to LA–ICP–MS analysis and CL images were acquired with a JEOL JXA-8900RL electron microprobe at the
Institute of Mineral Resources of the Chinese Academy of Geological Sciences, CAGS,
Beijing. Zircon U–Pb dating was performed using a Finnigan Neptune multi-collector
ICP–MS with a Newwave UP213 laser–ablation system at Institute of Mineral Resources,
CAGS, Beijing. Helium was used as the carrier gas to enhance the transport efficiency of the ablated material. The analyses were conducted with a beam diameter of 25 lm with a 10 Hz
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repetition rate and a laser power of 2.5J/cm2 (Hou et al., 2007). The masses 206Pb, 207Pb,
204(Pb+Hg) and 202Hg were measured by multi-ion-counters, while the masses 208Pb, 232Th,
235U and 238U were collected by Faraday cup. Zircon GJ1 was used as the standard and zircon
Plesovice was used to optimize the machine. U, Th and Pb concentrations were calibrated using 29Si as the internal standard and zircon M127 (U: 923 ppm; Th: 439ppm; Th/U: 0.475,
Nasdala et al., 2008) as the external standard. 207Pb/206Pb and 206Pb/238U ratios were calculated using the ICPMS DataCal 4.3 program. The common–Pb was not corrected because of the high 206Pb/204Pb ratios (>1000). Data with abnormally high 204Pb counts were deleted. The zircon Plesovice is dated as unknown samples and yielded weighted mean 206Pb/238U age of
337±2 Ma (2SD, n = 12), which is in good agreement with the recommended 206Pb/238U age of 337.13±0.37 Ma (2SD) (Sl ma et al., 2008). The age calculation and plotting of concordia diagrams was performed using Isoplot/Ex 3.0 (Ludwig, 2003).
Mineral chemistry was carried out at the Electron Microprobe Laboratory of the Chinese
Academy of Geological Sciences (CAGS) in Beijing, China. A JXA-8800 electron microprobe was used for these measurements and was operated at a voltage of 20 kV, beam ACCEPTED MANUSCRIPT current of 2 × 10–8 A, and beam diameter of 5 μm, with the analytical error of lower than 0.01% (Xu et al., 2010).
Major and trace elements, and Sr–Nd isotopes were analyzed at the CNNC Beijing
Research Institute of Uranium Geology. Major elements were measured using X-ray fluorescence spectrometry (XRF) on fused glass beads, with a precision better than 1%. Trace elements were analyzed with inductively coupled plasma–mass spectrometry (ICP–MS), and
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the precision for minor element content is better than 5%, which is extremely low (<10–8).
Sr–Nd isotopic tests used the ISOPROB-T thermalionization mass spectrometer, according to
GB/T17672-1999 “Determinations for isotopes of lead, strontium and neodymium in rock samples”. The ICP–MS method measured Rb, Sr, Sm, Nd contents in order to calculate
143Sm/144Nd (Zhao et al., 2010). Test precision of 87Rb/86Sr and 143Nd/144Nd is better than 2% and 0.5%, respectively.
5 Results
5.1 Mineralogy and mineral chemistry
We focused on the characteristics and mineral chemistry of the plagioclase, K-feldspar, hornblende, and biotite of the Shilu granodiorite.
5.1.1 Plagioclase
Plagioclase, one of the main rock-forming minerals in the granodiorite, occurs as tabular and prismatic shapes, subhedral to euhedral, 0.4–3mm in size, and usually exhibiting a well-developed polysynthetic twinning (Fig. 2B, 2D, 2F). Representative plagioclase major element componentsACCEPTED analyzed by microprobe MANUSCRIPT are given in Table 1. SiO2 contents of the plagioclase vary from 54.89 to 57.53 wt% (average = 55.87 wt%). Its composition ranges from An54Ab45Or1 to An44Ab55Or1, indicating that the plagioclase in the Shilu intrusion is mainly andesine with minor labradorite (Fig. 3). Some plagioclase crystals show compositional zoning (Fig. 2B, 2D, 2F), from the core to rim, Na2O content increases from
5.10% to 6.17% whereas CaO decreases from 11.03% to 9.06%.
5.1.2 K-feldspar
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K-feldspar is another main rock-forming mineral of the Shilu granodiorite. Most of
K-feldspars are generally prismatic (though some are tabular) (Fig. 2B, 2C). Most K-feldspars exhibit Carlsbad twins and some are zoned. K-feldspars were analyzed in polished sections using the electron microprobe (Table 2). The analytical results show that K-feldspars contain a little CaO (0.00%–0.07%). They have high contents of Or (87–92 wt%), minor Ab (8–13 wt%), and negligible An component of 0–0.3 wt%.
5.1.3. Biotite
Biotite is a common mineral in the Shilu granodiorite, it occurs as sheet-like and euhedral crystals (Fig. 2B–D, 2F), and displays weak chloritization (Fig. 2D). The major element compositions of the biotite are listed in Table 3. SiO2 content ranges from 36.46 to
37.63 wt%, averaging 36.85 wt%. The MgO contents varies from 12.15 to 13.55 wt%, averaging 12.63 wt%. The FeO/MgO ratios vary from 1.21 to 1.51, averaging 1.40, and are similar to biotites of calc-alkaline granitoids (1.76). The Mg/(Mg + Fe) ratios range from 0.54 to 0.60 (average = 0.56), which is higher than that of biotite of S-type granitoids (0.4; Liu and
Wang, 1994). Biotite tetrahedral AlVI average values (0.11) of the Shilu granodiorite are also lower than correspondingACCEPTED values of S-type MANUSCRIPT granites (0.353–0.561; Whalen and Chappell,
1988). In the biotite classification diagram (Figure. 4a; Foster, 1960), when combined with electron microprobe analyses and cation number (calculated on the basis of 11 oxygen atoms;
Table 3), the biotite of the Shilu granodiorite can be classified as magnesio-biotite, characterized by Mg-rich and low-AlVI, which is diagnostic of I-type granitoids.
5.1.4 Hornblende
Hornblende is the other main mafic mineral and is evenly distributed in the Shilu
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granodiorite intrusion. Hornblende occurs as subhedral to euhedral crystals (Fig. 2B, 2E, 2F) and is 0.05–1.0 mm in size. Length/width ratios of the hornblende vary from 1:1 to 3:1. This amphibole displays different degrees of chloritization. It was analyzed in polished thin sections by electron microprobe (Table 4). In the Shilu granodiorite intrusion, SiO2 contents of hornblende vary from 48.82 to 50.90 wt% (average = 49.64 wt%), whereas CaO and MgO contents are 11.47–11.95 wt% and 13.20–15.61 wt%, respectively. The Mg/(Fe2+ + Mg) ratios are from 0.74 to 0.79 (average = 0.77), but the hornblendes are low in FeO (12.10–14.26 wt%) and Ti-poor in chemical formula (0.059–0.120) (Table 4). According to the amphibole classification scheme of Leake et al. (1997), hornblende of the Shilu granodiorite is chiefly magnesiohornblende and tschermakite (Fig. 4b). The chemistry of the Shilu hornblende is identical to the composition of amphibole generally formed in I-type granitoids (Clements and
Wall, 1984).
5.2 U–Pb zircon chronology
Zircon grains are colorless or yellow, occur as euhedral, elongate grains of 120–280 μm in size and have a length/width ratio of 1.5:1 to 3:1. In CL images (Fig. 5), most zircon grains are homogeneousACCEPTED or have oscillatory or planar MANUSCRIPT zoning, which is typical of magmatic zircons.
The cores are unzoned with strong luminescence, or have oscillatory zones with medium CL brightness. The rims are of variable width and have oscillatory zoning with a euhedral shaped rim. Analyzed zircons exhibit low Th/U ratios (0.44–1.01), indicative of a magmatic origin
(Belousova et al., 2002). Ten spot analyses of the granodiorite, yielded a 206Pb/238U age of
107.02±0.72 Ma, with a mean square weighted deviation (MSWD) of 0.25 (Table 5; Fig. 6).
5.3 Whole rock major and trace elements
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Eight granodiorite samples from the Shilu intrusion were chosen for major and trace element analyses, and the results are reported in Table 6. The results show a range of SiO2 contents from 63.43 to 65.03 wt%, the Al2O3 and MgO abundances range from 15.82 to 16.36 wt% and 2.07 to 2.28 wt%, respectively. CaO, Na2O, and K2O contents are 4.76 to 5.1 wt%,
2.99 to 3.19 wt%, and 2.46 to 2.86 wt%, respectively, and the contents of P2O5 and TiO2 are
0.157%–0.171% and 0.453%–0.493%, respectively. Fe2O3 contents (3.94%–4.41%) exceed the FeO contents (2.05%–2.45%), and Na2O/K2O ratios are 1.06–1.30, falling in the calc-alkaline series field on the SiO2 vs. K2O diagram (Fig. 7a). All the calculated A/CNK values (molar Al2O3/(CaO + Na2O + K2O)) are from 0.94 to 0.98, indicating that these rocks are metaluminous (Fig. 7b). All samples have relatively low LOI (loss on ignition) values of
1.0–2.93 wt%, consistent with the relative lack of late hydrothermal alteration.
Figure (8a) shows chondrite-normalized rare earth element (REE) distribution patterns
(Boynton, 1984; McDonough et al., 1992). Their ∑REE ranges from 111.9 to 134.0 ppm, characterized by a right–inclined shape with more moderate LREE/HREE fractionation (light
REE/heavy REE; (La/Yb)N = 9.10–12.56) and small negative Eu anomalies (Eu/Eu* =
0.83–0.90) (TableACCEPTED 6; Fig. 8a). In addition, theMANUSCRIPT Yb contents (2.22–2.65 ppm) are higher than
1.9 ppm.
The trace element spider diagram (Fig. 8b) shows the relative enrichment of large ion lithophile elements (LILE) such as Th, U, Rb, K, and Pb with depleted high field strength elements (HFSE) such as Nb, P, Ba, Ti, Zr, and Eu. High Rb and low Ba and Sr might suggest fractional crystallization of orthoclase and plagioclase, whereas the moderate Eu depletion is probably related to plagioclase fractionation. The depletion in P and Ti indicates that the
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magma underwent fractional crystallization of apatite, titanite, and Ti-rich minerals (Cao et al.,
2014).
5.4 Whole rock Sr–Nd isotopes
87 86 The Sr–Nd isotope data are listed in Table 7. The initial Sr/ Sr ratios and εNd(t) values were calculated at 107 Ma corresponding to the zircon U–Pb ages. The samples have high
87 86 87 86 ( Sr/ Sr)I values, and show little variability in initial Sr/ Sr ratios (0.70952–0.70971), with the values being lower than the average continental crust values (0.719). The samples have slightly negative εNd(t) values of –8.4 to –0.8.
6 Discussion
6.1 Age implications
As a typical skarn deposit, the orebodies of the Shilu deposit occur in the contact zone of
Carboniferous carbonates and the Shilu granodiorite intrusion (Fig. 1c), indicating that they have a genetic relationship. Therefore, the mineralization and the Shilu intrusion possibly formed simultaneously. However, previous rock-forming Rb–Sr age (122±1 Ma), single zircon evaporationACCEPTED dating method (126 Ma), MANUSCRIPT and K–Ar mineralization age (89 Ma) are not consistent each other (Zhao et al., 1985; Zhai et al., 1999). Yu et al. (1988) obtained a consistent 39Ar–40Ar plateau age (99–101 Ma) from three minerals K-feldspar, biotite, and plagioclase in the Shilu granodiorite, indicating that ca.100 Ma represents the rock-forming age. However, Li et al. (2000) proposed that the plateau age (100 Ma) represents the age of a late thermal disturbance event. The LA–ICP–MS U–Pb age of 107±0.72 Ma for the Shilu granodiorite we obtained is quite consistent with molybdenite Re–Os isochron age of
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104.1±1.3 Ma, and the weighted average model ages of 104.1±1.3 Ma and 104.34±0.66 Ma
(Zhao et al., 2012). Therefore, 107±0.72 Ma can be considered as the best estimate of the emplacement age of the intrusion with the mineralization event of the Shilu Cu–Mo deposit occurring at 104 Ma. These ages belong to the Early Cretaceous and are compatible with the mineralization age of the Tiantang skarn Cu–Pb–Zn deposit located to the northeast of the
Shilu deposit, which yields a sphalerite Rb–Sr isochron age of 97.87±0.96 Ma (Zheng et al.,
2013a).
The Yangchun basin is well endowed with polymetallic deposits in the Yunkai area, western Guangdong province. Except for the porphyry–skarn Cu–Mo and Cu–Pb–Zn deposits there are also numerous Cu–Fe and W–Sn deposits in the same basin. The W-Sn deposits are closely related to felsic magmatism.
The hornblende 40Ar–39Ar plateau age of the Mashan intrusion is 163.6±2.0 Ma (Li et al.,
2000) and the SIMS U–Pb isotopic age of the Gangmei intrusion is 165.7±1.3 Ma (Huang et al., 2013), Thus the rock-forming ages of these intrusions are close to the mineralization ages of the Mange’ling, Potoumian, Didougang and other skarn Cu–Fe deposits. We suggest that ACCEPTED MANUSCRIPT these Cu–Fe ores formed in the Mid-Late Jurassic and are associated with the Jurassic magmatism along the Qin-Hang belt in South China (170–155 Ma) (Mao et al., 2007, 2008,
2013). From the perspective of geochronology, the Shilu Cu–Mo and the Tiantang Cu–Pb–Zn deposits are part of the Cretaceous mineralization events of South China, and their formation ages are later than the Cu–Fe deposits in the Yangchun basin by about 50 Ma.
Mao et al. (2004, 2007, 2008, 2013) and Yuan et al. (2008, 2011, 2012) suggested that large-scale W–Sn mineralization of Nanling area, central part of South China, occurred in the
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Middle Jurassic (150–160 Ma) (Mao et al., 2008, 2013). However, according to current information, W–Sn deposits in the Yangchun basin and adjacent areas may have formed in the Late Cretaceous. For example, the Yangchun vein-type Sn deposit formed at 76 Ma (Yu et al., 1998); the Yinyan porphyry Sn deposit formed at 90 Ma (Mao et al., 2008), and the molybdenite Re–Os weighted average age of the Dajinshan quartz-vein-type W–Sn–Mo deposit at the northeastern edge of the Luoding basin is 82.5±3.1 Ma (Yu et al., 2012). In addition, the molybdenite Re–Os isochron age of the Yingwuling polymetallic W deposit is
83.0±1.7 Ma (Zheng et al., 2013b) and the zircon LA–ICP–MS U–Pb age of the host rocks associated with mineralization is 81.31±0.55 Ma (Zheng et al., 2013c).
Thus, the temporal order of the metal assemblages is as follows (from oldest to youngest): copper–iron, copper (molybdenum), copper–lead–zinc, and tungsten–tin.
6.2 Petrogenesis
The origin of high-K granites, particularly those classified as calc-alkaline I-type granites, remains a topic of debate (Roberts and Clemens, 1993; Liegeois et al., 1998). Models for the generation of IACCEPTED-type granites range from MANUSCRIPT mixing of mantle-derived magmas with crustal-derived materials (Dickinson, 1975; Hildreth and Moorbath, 1988), to direct melting of intermediate meta-igneous rocks to hydrous medium- to high-K mafic rocks (Roberts and
Clemens, 1993; Sisson et al., 2005). Various tectonic settings have also been proposed for such rocks, ranging from lithospheric extension in a post-collisional setting to subduction at an active continental margin (Roberts and Clemens, 1993).
Harker diagrams for the Shilu granodiorite show that TiO2, MgO, TFe2O3, CaO, K2O,
Na2O and P2O5 partly have weak correlations with SiO2 (Fig. 9), suggesting that fractional
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crystallization probably has affected the rocks during their magmatic evolution. In the Shilu intrusion, all of the samples fall into the OGT (non-fractionated M-, I- and S-type granites) field in a plot of (K2O + Na2O)/CaO versus Zr + Nb + Ce + Y (Fig. 10a). These results cannot be easily interpreted as a fractional crystallization process. In the La/Yb vs. La diagram (Fig.
10b), samples of the Shilu granodiorite are consistent with a partial melting trend and lack the typical signs of fractional crystallization. This suggests that the effects of partial source melting had a greater effect on the geochemical composition of the granodiorites than fractional crystallization. The absence of significant Eu anomalies eliminates K-feldspar as a potassic phase (Zhu et al., 2014). Melts in equilibrium with phlogopite are expected to have relatively high Rb/Sr (>0.1) and low Ba/Rb (<20) ratios (Furman and Graham, 1999), which indicates that phlogopite was a more likely potassic phase than amphibole in the source area
(Fig. 10c).
Trace element and Sr isotope data can be used to trace the magma sources of the rocks.
The REE patterns of rocks in the Shilu granodiorite exhibit light REE enrichment ([La/Yb]N >
9), but are low in total REE (<200 ppm), and have moderately negative Eu anomalies (δEu =
0.83–0.90, averageACCEPTED = 0.86). These REE characteristics MANUSCRIPT are different from those of crustal derived granitoids (Rudnick et al., 1985; Taylor and Mclennan, 1995), suggesting that the
Shilu granodiorite originated from the mantle. Our geochemical data are shown on the Nb versus Y, Rb vs. (Y + Nb), Rb versus (Yb + Ta) and Ta vs. Yb diagrams (Fig. 11), in which it can be seen that all samples fall in the fields of volcanic arc granite (VAG) and syn-collision granite (Syn-COLG). These results indicate that the granitoids were generated in an arc setting. In the δEu versus (La/Yb)N diagram (Fig. 12a), all samples fall into the crust–mantle
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type field. Strontium isotope studies (Chen et al., 1993; Tang et al., 1998) have indicated that
87 86 the Shilu intrusion has ( Sr/ Sr)i ratios of 0.70952–0.70971, which also require contributions from a mix of mantle-derived and continental crust magmas.
To some extent, the chemistry of hornblende and biotite can be used to identify magma sources. Almost all of the hornblende data fall into the mixed-source field of crust–mantle in a plot of TiO2 vs. Al2O3 (Fig. 12b). Similarly, all of the biotite compositions lie in the crust–mantle mixed-source field in the diagram ∑FeO/(∑FeO + MgO) versus MgO (Fig. 12c).
This implies that both the hornblende and biotite in the investigated intrusion are the products of crust–mantle mixed-source magmas, which is consistent with the trace element and Sr isotopic results.
The Shilu granodiorite has a relatively low εNd/t-t value (-0.8 to -8.4, average = -5.93)
87 86 and high n( Sr)/n( Sr)i value (0.70952–0.70971, average = 0.70962), and Nd isotopes yield two-stage depleted mantle Nd model ages of 969–1590 Ma. When comparing the Shilu intrusive rocks with other Late Yanshanian granites in South China on the εNd/t-t diagram (Fig.
13a), nearly half of the Late Yanshanian granites are located within the field of Proterozoic crustal evolution ACCEPTED region in South China, closeMANUSCRIPT to the upper part of the evolution domain, showing that they are derived mainly from Proterozoic crust with a low thermal maturity, whereas the other half of the granites are located between the Proterozoic crustal evolution area of South China and the mantle evolution line of chondrite, indicating that they contain more mantle components. In the εNd/t-t figure (Fig. 13a), the Shilu granodiorite is located between the Proterozoic crustal evolution area of South China and the mantle evolution line
87 86 of chondrite. In the εNd/t-n( Sr)/n( Sr)i figure (Fig. 13b), the granodiorite is located in the
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lower right quadrant, which is consistent with the distribution of I-type granites in South
China, clearly indicating the characteristics of a mixed crust–mantle source and illustrating the significant difference between the various petrochemical evolution trends (Li et al., 2001).
Therefore, many geochemical features of the Shilu granodiorite, particularly the arc-like
LREE patterns and trace element spidergrams, as well as the initial Sr–Nd values, suggest the influence of crustal sources and a geochemical affinity to I-type granites. These geochemical features possibly suggest that the granodiorite was produced in an active subduction system, as indicated by the arc-like features of the studied granodiorite (Nb and Ta depletions relative to Th and La; Fig. 8b). The characteristics of volcanic arc and syn-collision granite are well defined in the Y-Nb, Y+Nb-Rb, Ta+Yb-Rb and Yb-Ta diagrams of tectonic discrimination.
However, there is a transitional regime from compression to extension in East China after 135
Ma (Mao et al., 2003a,b; 2005; Shu et al., 2006; Dong et al., 2007; Maruyama et al., 1997;
Niu et al., 2003; Wang et al., 2002; Li et al., 2008), and the changing direction of the
Paleo-Pacific plate from oblique subduction to parallel to the continental margin (Mao et al.,
2013). It follows that the Shilu granodiorite was unlikely produced in an active subduction system. Instead, ACCEPTEDthe Cretaceous mafic dikes MANUSCRIPT distributed east and west of the Wuyishan
Mountain have different characteristics, reflecting active continental margin and intraplate extensional settings, respectively (Xie et al., 2006). The arc-like features were probably heritable and are associated with residual subducted slab fragments of Jurassic rather than being indicative of an active arc environment.
6.3. Physico-chemical crystallization conditions and significance for ore formation
The main conditions of magma melting, temperature and pressure, can constrain the
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origin and evolution of magmatic rocks, and the depth of the source can be investigated by establishing the formation temperature and pressure of the magma. Currently, estimations of the original temperature and pressure of granitic magma are based mainly on experimental petrology information. However, other means are required to obtain this information for the
Shilu intrusion, due to the various granites presenting limited experimental petrology information.
Here, we use biotite and hornblende thermobarometry to calculate the temperature and pressure conditions during the crystallization of the Shilu grandiorite intrusion. The total Al content of hornblende (AlIV + AlVI) can be used to calculate the crystallization pressure. The following equation proposed by Johnson and Rutherford (1989) was used to estimate the crystallization depth and pressure, with the crystallization depth calculated from a pressure–depth relationship of 1kbar ≈ 3.3 km:
P (kbar) = –3.46 + 4.23 × TAl (±0.5 kbar) where TAl is the total Al content in the hornblende estimated on the basis of 23 oxygens.
The hornblende–plagioclase geothermometer proposed by Blundy and Holland (1990) was used to estimateACCEPTED the crystallization temperature. MANUSCRIPT Temperatures were calculated as follows: 0.677P48.98Y Si 4 T= and K={ }× XPlag 0.04290.008314InK 8Si Ab where Si is the atomic number per unit of hornblende, P is pressure in kbar, T is the absolute
–2 temperature in K, and is the Ab value of plagioclase (×10 ). When XAb < 0.5, Y =
2 –0.806 + 25.5 (1 – XAb) and when XAb > 0.5, Y = 0.
The hornblende crystallization pressures and temperatures from the Shilu intrusion are summarized in Table 4. For the granodiorite, pressures fall into two ranges of 0.02–0.81 and
20 ACCEPTED MANUSCRIPT
1.00–2.34 kbar, corresponding to depths of 0.05–2.68 and 3.31–7.71 km, respectively.
Etsuo et al. (2007) suggested that the total aluminum content of biotite in granites is related to the crystallization pressure. Application of a hornblende–biotite geothermometer to the Shilu Cu–Mo deposit yields a pressure of 0.8–2 kbar (Fig. 14a), corresponding to depths of 2.64–6.6 km.
A Ti vs. Mg/(Mg + Fe) temperature diagram was used to calculate the crystallization temperature of biotite (Fig. 14b), values for the granodiorite of 680–780°C.
Therefore, the hornblende and biotite thermobarometry constrain the temperature and pressure conditions for the formation of the granodiorite to 686–780°C and 1.00–2 kbar
(depth = 3.31–6.6 km). The granite formed at low temperatures, and as these temperatures are lower than the average temperature of I-type granites (781°C; King et al., 1997), its formation may have been related to the addition of fluid, which also indicates that it was probably inherited from its parental magmas.
Ishihara (1977) defined two series of granites based on their Fe–Ti oxide mineralogy: (1)
The more reduced ilmenite-series granites contain ilmenite as the only Fe–Ti oxide and may also contain pyrrhotite,ACCEPTED and (2) the more oxidized MANUSCRIPT magnetite-series granites contain magnetite and ilmenite and may also contain pyrite or pyrrhotite plus titanite. In the Shilu intrusion, the
Ⅵ TiO2 and Al abundances range from 3.61% to 4% and 0 to 0.1, respectively. According to
Albuquerque (1973), higher temperatures favour accommodation of Ti instead of AlⅥ which is higher in the biotite. The high Ti contents and low AlⅥ in biotite corresponds to high temperature of crystallization and high-oxygen fugacities (Buddington and Lindsley, 1964;
Albuquerque, 1973). The co-existence of magnesio-biotite and accessory minerals such as
21 ACCEPTED MANUSCRIPT
primary magnetite and titanite in the Shilu intrusion also indicates that the magmas have a high oxygen fugacity. The chemical compositions of biotite are displayed in a Fe3+–Fe2+–Mg diagram (Wones and Eugeter, 1965), and all plot between the Ni–NiO and Fe2O3–Fe3O4 buffer lines (Fig. 15). Based on empirical mineral associations, the link between oxidized felsic magmas and mineralization is well-known (Hedenquist and Lowenstern 1994; Ballard et al. 2002; Mungall 2002). Previous studies have demonstrated that mantle-derived magmas with high oxygen fugacity are consistent with the inclusion of ore-forming elements in the magma (Silltoe, 1997). Cu porphyries or Mo-bearing granites are usually related to oxidized melt systems (Meinert et al., 2005; Zhang et al . 2011; Li et al. 2012,Qiu et al., 2013).
Moreover, copper in a magma with high oxygen fugacity will become enriched during differentiation and partition into a magmatic-hydrothermal fluid (Pasteris 1996; Urich et al.
1999; Ballard et al. 2002; Sun et al. 2004). Oxygen fugacity not only affects the melt sulfur abundance, but also fluid–melt differentiation, the metal content of the related skarns (Simon et al., 2003), and mineral composition and stability (Einaudi et al., 2003). Therefore, fluid–rock interactions occurred readily between the magmatic fluids and carbonate country rocks to form CuACCEPTED-bearing skarn particularly MANUSCRIPT at the retrograde alteration stage (Zhang et al.,
2010).
6.4 Tectonic implications
Although western Guangdong is far from the subduction zone of the Pacific and
Eurasian plates, the geodynamic evolution of the Mesozoic lithosphere in this area was controlled by interaction between these two plates (Mao et al., 2004, 2005, 2007, 2008; Shu et al., 2006; Dong et al., 2007), which was probably resulted from the oblique subduction of the
22 ACCEPTED MANUSCRIPT
Izanagi plate on the Pacific margin (Maruyama et al., 1997). As the subduction of the Izanagi plate continued, continental crust gradually thickened and developed a series of NE-trending lithospheric extensional belts and deep faults in a back-arc setting (Mao et al., 2007, 2008 ,
2011a, 2011b, 2013). After 135 Ma, the movement direction of the Paleo-Pacific plate changed from oblique subduction to one parallel to the continental margin (Mao et al., 2013).
Lithospheric extension of South China took place and the majority of the related ore systems are therefore located in volcanic basins and rift basins (Mao et al., 2011a, b), which can be ascribed to regional large-scale lithospheric thinning and delamination of the thickened lithosphere and thermal erosion (Mao et al., 2013).
The various mineral systems that are concentrated in the Yangchun basin may indicate that the area experienced a strong crust–mantle interaction and that the granite associated with mineralization has evolved from felsic to intermediate during this process. Therefore, we propose that, as part of the Jurassic and Cretaceous granites in South China, copper–iron, copper–molybdenum or copper–lead–zinc, and tungsten–tin deposits, as well as granite associated with the polymetallic mineralization, have different geochemical characteristics ACCEPTED MANUSCRIPT and tectonic settings.
There are some differences in the age, magma source, and composition of the
Jurassic–Cretaceous igneous activity of the Yangchun basin in western Guangdong (Li et al.,
2001; Huang et al., 2013; Zheng et al., 2013c). Shilu, Mashan, Gangmei and Yingwuling are located in the Hunan–Guangxi–Guangdong belt, which is one of four late Mesozoic belts with low Nd model ages (Zhou et al., 2007), which are distributed along the southern end of the
Wuchuan–Sihui Fault. The low Nd-model ages of granite are caused mainly by the addition
23 ACCEPTED MANUSCRIPT
of mantle material. All of the above factors may be related to subduction of the Pacific plate, which would have caused back-arc extension, crustal thinning, and asthenospheric mantle upwelling (Zhou et al., 2007). However, the pre-Jurassic granites formed by the melting of crustal material, as implied by their older Nd-model ages (Zhou et al., 2007). Li et al. (1999) suggested that from the Early to Late Jurassic, the lithosphere in the Yangchun area stretched and thinned, while further increases in the temperature gradient led to extensive remelting of the crust. The source of the Late Jurassic shoshonitic intrusive rocks was probably shallower than that of the Early Jurassic shoshonitic rocks, and much closer to the upper part of the lithospheric mantle. However, the source of the Cretaceous calc-alkaline magma area was further upward in the lower crust, indicating that the lithosphere stretched and thinned evenmore .
From the above, the East China continent, including the western Guangdong, was in continuing extension after 135Ma (Goldfarb et al., 2007; Mao et al., 2007). Regionally,
Cretaceous rift basins developed, including the Luoding, Yangchun, and Huaiji basins, all of which are the sites of multi-metal mineral resources. Stratigraphically, nappe structures ACCEPTED MANUSCRIPT generally occur along the basement in Cretaceous continental sedimentary sequences. For example, the Lower Cretaceous rocks in the Luoding basin moved from south to north along the basement contact (Zhao et al., 2012). Li et al. (1997) suggested that the 103–110 Ma mafic dikes of northern Guangdong reflect a tensional regime for the southeast area in the late
Early Cretaceous (105±5 Ma). In addition to the granodiorite of the Shilu deposit, the U–Pb zircon age of the Deqing monzogranite is 99±2 Ma, the U–Pb age of the Diaocun granodiorite is 104±3 Ma (Geng et al., 2006), and the zircon U–Pb age of the Baigang granite is 106.4±0.7
24 ACCEPTED MANUSCRIPT
Ma (Gao et al., 2005). At this time, felsic volcanic rocks also formed, including the
Ma’anshan and Zhougongding rhyolites, which yield a zircon U–Pb isotope age of 100±1 Ma.
The geochemical signsatures of these intrusive–extrusive rocks are similar to those of the intermediate–felsic igneous rocks along the coast of Zhejiang and Fujian, suggesting that they both formed in a continuously extensional environment (Gao et al., 2005). Therefore, a lithospheric extensional regime was the Cretaceous geodynamic setting of South China, including western Guangdong (Mao et al., 2004, 2007, 2008; Hu et al., 2007), and the
Yangchun-Shilu copper deposit is the product of this tectonic setting.
7 Conclusions
(1) LA–ICP–MS U–Pb zircon dating of the Shilu granodiorite associated with porphyry-skarn copper deposit yields an age of 107±0.72 Ma, which is consistent with molybdenites Re–Os age of 104.1±1.3 Ma, suggesting that the magmatism was coeval with the timing of mineralization in Early Yanshanian period.
(2) The Shilu granodiorite is calc-alkaline and characterized by enrichment in silica, alkalis, calcium, light REEs, and large ion lithophile elements, and depleted in heavy REEs ACCEPTED MANUSCRIPT and high field strength elements. The Shilu granodiorite fits the I type granitoids, with both mantle and crustal contributions.
(3) Plagioclase in the Shilu granodiorite is primarily andesine-labradorite (An = 44–54 wt%), whereas biotite is magnesio-biotite and hornblende is Mg-rich calcic hornblende. These, imply that the Shilu intrusion is the product of crust–mantle mixed-source melts, which is consistent with the trace element and Sr–Nd isotopic results. Hornblende and biotite thermobarometry constrain the crystallization pressure and temperature of the granodioritic
25 ACCEPTED MANUSCRIPT
magma at 686–780℃and 1.0–2 kbar (depth=3.31–6.6 km), respectively. The chemical compositions of rock-forming minerals indicate that the parent magma formed in a high oxygen fugacity environment.
(4) The Shilu Cu–Mo deposit was formed in a consistently extensional environment and closely related to remelting of residual subducted slab fragments in the Jurassic.
ACCEPTED MANUSCRIPT
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Acknowledgments
The geological workers from the Shilu Cu–Mo Mine and Engineer Weipeng Lin, Zhixia
Ouyang and Yun Tian from Geology Bureau for Nonferrous Metals of Guangdong Province are thanked for their help during the field geological investigation. We would like to thank associate Professor Kejun Hou and Zhenyu Chen from the State Key Laboratory for
Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological
Sciences for his advice and assistance during electron microprobe analyses and LA–ICP–MS zircon U-Pb dating. We thank research assistant Qintao Zeng and Hegen Ouyang from the
Chinese Academy of Geological Sciences, and Dongyang Zhang, Bikang Xiong, Xinming
Zhao and Weiwei Zhou from the China University of Geosciences (Beijing) for her help during data analyses. We also thank Senior Engineer Mu Liu from the CNNC Beijing
Research Institute of Uranium Geology for her help during Sr–Nd isotope analyses. The work was financially supported by the National Basic Research Program of China (Grant No.
2012CB416704), China Geological Survey Project of the Ministry of Land and Resources
(Grant No. 12120114034301), the Central Commonweal Research Institutions Fundamental
Professional ExpensesACCEPTED Project (Grant No. K1323). MANUSCRIPT
27 ACCEPTED MANUSCRIPT
References
Albuquerque, A.C., 1973. Geochemistry of biotites from granitic rocks, northern Portugal
Geochemistry[J]. Geochimica et Cosmochimica Acta 37, 1779–1802.
Ballard, J.R., Palin. J.M., Campbell. I.H., 2002. Relative oxidation states of magmas inferred
from Ce(IV)/Ce(III) in zircon: application to porphyry copper deposits of northern Chile.
Contributios to Mineralogy and Petrology 144, 347–364.
Belousova, E.A., Griffin, W.L., O’Reilly, S.Y., 2002. Igneous zircon: trace element
composition as an indicator of source rock type. Contribution to Mineralogy and
Petrology 143, 602–622.
Blundy, J.D., Holland, T.J.B., 1990. Calcic amphibole equilibria and a new
amphibole–plagioclase geothermometer. Contributions to Mineralogy and Petrology 104,
208–224.
Boynton, W.V., 1984. Geochemistry of the rare earth elements: meteorite studies. In:
Henderson, P. (Ed.), Rare Earth Element Chemistry. Elsevier, Amsterdam, pp. 63–114.
Buddington, A.F., Lindsley. D.H., 1964. Iron-titanium oxide minerals and synthetic
equivalents. ACCEPTEDJournal of Petrology 5, 310 MANUSCRIPT-357.
Cai, M.H., Zhan, M.G., Peng, S.B., Meng, X.J., Liu, G.Q., 2002. Study of Mesozoic
metallogenic geological setting and dynamic mechanism in Yunkai area. Mineral Deposit 21,
254–269 (in Chinese with English abstract).
Clements, J.D., Wall, V.J., 1984. Origin and evolution of a peraluminous silicic ignimbrite
suite. The Violet Town Volcanics. Contributions to Mineralogy and Petrology 88,
354–371.
28 ACCEPTED MANUSCRIPT
Cooke, D., Hollings, P., Walshe, J.L., 2005. Giant porphyry deposits: Characteristics,
distribution, and tectonic controls. Economic Geology 100, 801–818.
Dickinson, W.R., 1975. Potash–depth (K–h) relations in continental-margin and intra-oceanic
magmatic arcs. Geology 3, 53–56.
Dong, S.W., Zhang, Y.Q., Long, C.X., Yang, Z.Y., Ji, Q., Hu, J.M., Chen, X.H., 2007. Jurassic
tectonic revolution in China and new interpretation of the Yanshan movement. Acta
Geological Sinica 81, 1449–1461 (in Chinese with English abstract).
Einaudi, M.T., Hedenquist, J.W., Inan, E., 2003. Sulfidation state of hydrothermal fluids. The
porphyry-epithermal transition and beyond. Society of Economic Geologists Special
Publication 10, 317–391 .
Etsuo, U., Sho, E., Mitsutoshi, M., 2007. Relationship between solidification depth of granitic
rocks and formation of hydrothermal ore deposits. Resource Geology 57, 47–56 .
Foster, M.D., 1960. Interpretation of the composition of trioctahedral mica. U.S. Geological
Survey Professional Paper, v. 354–B, pp. 11–48.
Furman, T., Graham, D., 1999. Erosion of lithospheric mantle beneath the East African Rift
system: geochemicalACCEPTED evidence from MANUSCRIPT the Kivu volcanic province. Developments in
Geotectonics 24, 237–262.
Gao, J.F., Ling, H.F., Sheng, W.Z., Lu, J.J., Zhang, M., Huang, G.L., Tan, Z.Z., 2005.
Geochemistry and petrogenesis of Liangyang granite composite, west Guangdong
province. Acta Petrologica Sinica 21, 1645–1656 (in Chinese with English abstract).
Geng, H.Y., Xu, X.S., O’Reilly, S.Y., Zhao, M., Sun, T., 2006. The Cretacous volcanic and
intrusion in Western Guangdong province, and their geological implicaion. Science in China
29 ACCEPTED MANUSCRIPT
(D Series) 36, 601–617 (in Chinese with English abstract).
Gilder, S.A., Gill, J., Coe, R.S., Zhao, X., Liu, Z., Wang, G., Yuan, K.R., Liu, W.L., Kuang,
G.D., Wu, H.R., 1996. Isotopic and paleomagnetic constraints on the Mesozoic tectonic
evolution of South China. Journal of Geophysical Research 101, 16137–16154.
Hedenquist, J.W., Lowenstern, J.B., 1994. The role of magmas in the formation of
hydrothermal ore deposits. Nature 370, 519–527
Henry, D.J., Guidotti, C.V., Thomoson, J.A., 2005. The Tisaturation surface for
low-to-medium pressure metapelitic biotites: implications for geothermometry and Ti
substitution mechanisms. American Mineralogist 90, 316–328 .
Hildreth, W., Moorbath, S., 1988. Crustal contributions to arc magmatism in the andes of
central Chile. Contributions to Mineralogy and Petrology 98, 455–489.
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 isotope microanalysis of zircon and its
geological applications. Acta Petrologica Sinica 23, 2595–2604 (in Chinese with English
abstract).
Hu, R.Z., Bi, X.W.,ACCEPTED Peng, J.T., Liu, S., Zhong,MANUSCRIPT H., Zhao, J.H., Jiang, G.H., 2007. Some
problems concerning relationship between Mesozoic-Cenozoic lithospheric extension
and uranium metallogenesis in South China. Mineral Deposits 26, 139–152 (in Chinese
with English abstract).
Huang, H.Y., Li, X.H., Li, Z.X., Li, X.W., 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.
30 ACCEPTED MANUSCRIPT
Jahn, B.M., 1974. Mesozoic thermal events in southeast China. Nature 248, 480–483.
Jiang, C.Y., An, S.Y., 1984. On chemical characteristics of calcic amphiboles from igneous
rocks and their petrogenesis significance. Journal of Mineralogy and Petrology 3, 1–9 (in
Chinese with English abstract).
Johnson, M.C., Rutherford, M.J., 1989. Experimental calibration of the aluminiumin-hornble-
nde geobarometer with application to Long Valley caldera (California) volcanic rocks.
Geology 17, 837–841.
King, P.L., White, A.J.R., Chappell, B.W., Allen, C.M., 1997. Characterization and origin of
aluminous A-type granites from the Lachlan Fold Belt, southeastern Australia. Journal of
Petrology 38, 371–391.
Leake, B.E., Woolley, A.R., Arps, C.E.S., 1997. Nomenclature of amphiboles report of the
subcommittee on amphiboles of the international mineralogical association, commission
on new mineral and mineral names. American Mineralogist 82, 1019–1037.
Li, C.Y., Zhang, H., Wang, F.Y., Liu, J.Q., Sun, Y.L., Hao, X.L., Li, Y.L., Sun, W.D., 2012.
The formation of the Dabaoshan porphyry molybdenum deposit induced by slab rollback.
Lithos 150, 101ACCEPTED–110. MANUSCRIPT
Li, X.H., Hu, R.Z., Rao, B., 1997. Geochronology and geochemistry of cretaceous mafic dikes
from northern Guangdong, SE China. Geochimica 26, 14–31 (in Chinese with English
abstract).
Li, X.H., Zhou, H.W., Liu, Y., Li, J.Y., Chen, Z.H., Yu, J.S., Gui, X.T., 2000. Mesozoic
shoshonitic intrusives in the Yangchun Basin, western Guangdong, and their tectonic
significance:Ⅰ. Petrology and isotope geochronology. Geochimica 29, 513–520 (in Chinese
31 ACCEPTED MANUSCRIPT
with English abstract).
Li, X.H., Zhou, H.W., Liu, Y., Li, J.Y., Chen, Z.H., Yu, J.S., Gui, X.T., 2001. Mesozoic
shoshonitic intrusives in the Yangchun Basin, western Guangdong, and their tectonic
significance: Ⅱ. Trace elements and Sr–Nd isotopes. Geochimica 30, 57–65 (in Chinese
with English abstract).
Li, J.W., Zhao, X.F., Zhou, M.F., 2008. Origin of the Tongshankou porphyry–skarn Cu–Mo
deposit, eastern Yangtze craton, Eastern China: geochronological, geochemical and Sr–
Nd–Hf isotopic constraints. Miner Deposita 43, 315– 336.
Liegeois, J.P., 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.
Lin, W.W., Yin, X.L., 1998. The forming physico-chemical conditions of Linglong granitic
complex and its geological significance. Bulletin of the Chinese Academy of Geological
Sciences 19, 40–49 (in Chinese with English abstract).
Liu, Z.S., Wang, J.M., 1994. Geology and Geochemistry of Granites in Southern Tibetan
Plateau. SichuanACCEPTED Science and Technology MANUSCRIPT Press, Chengdu, pp. 1–133 (in Chinese).
Ludwig, K.R., 2003. User’s Manual for Isoplot/Ex. Version 3.00: A geochronological toolkit for
Microsoft Excel. Berkeley Geochronology Center Special Publication, 4, 1–70.
Ma, D.Q., Zhao, Z.J., Lin, H.K., 1985. Petrologic features and genesis of xenoliths in Gangmei
and Shilu type granitoids from Yangchun basin, Guangdong province. Bulletin of the
YiChang Institute of Geology and Mineral Resources Chinese Academy of Geological
Sciences 10, 59–72 (in Chinese with English abstract).
32 ACCEPTED MANUSCRIPT
Mao, X.D., Liu, Y.H., Huang, S.J., 2003a. Study on the mineralizing age of the
Changkeng–Fuwan Au–Ag deposit, Guangdong Province. Progr Nat Sci 13,1325–1328 (in
Chinese with English abstract).
Mao, J.W., Wang, Y.T., Zhang, Z.H., Yu, J.J., Niu, B.G., 2003b. Geodynamic setting of
Mesozoic large-scale mineralization in the North China and adjacent area: implication from
the highly precise and accurate ages of metal deposits. Science in China (Series D) 33,
838–851.
Mao, J.W., Xie, G.Q., Li, X.F., Zhang, C.Q., Mei, Y.X., 2004. Mesozoic large–scale
mineralization and multiple lithospheric extension in South China. Earth Science Frontiers
11, 45–55 (in Chinese with English abstract).
Mao, J.W., Xie, G.Q., Zhang, Z.H., Wang, Y.T., Zhang, C.Q., Li, Y.F., 2005. Mesozoic
large-scale metallogenic pulses in North China and corresponding geodynamic settings.
Acta Petrologica Sinica 21, 169-188 (in Chinese with English abstract).
Mao, J.W., Xie, G.Q., Guo, C.L., Chen, Y.C., 2007. Large-scale tungsten–tin mineralization
in the Nanling region, South China: Metallogenic ages and corresponding geodynamic
processes. ActaACCEPTED Petrologica Sinica 23, 2329 MANUSCRIPT–2338 (in Chinese with English abstract).
Mao, J.W., Xie, G.Q., Guo, C.L., Yuan, S.D., Chen, Y.B., Chen, Y.C., 2008. Spatial-temporal
distribution of Mesozoic ore deposits in South China and their metallogenic settings.
Geological Journal of China Universities 14, 510–526 (in Chinese with English abstract).
Mao, J.W., Xie, G.Q., Cheng, Y.B., Chen, Y.C., 2009. Mineral deposit models of Mesozoic ore
deposits in South China. Geological Review 55, 347–354 (in Chinese with English abstract).
Mao, J.W., Chen, M.H., Yuan, S.D., Guo, C.L., 2011a. Geological Characteristics of the
33 ACCEPTED MANUSCRIPT
Qinhang (or Shihang) Metallogenic Belt in South China and Spatial–Temporal Distribution
Regularity of Mineral Deposits. Acta Geologica Sinica 85, 636–658 (in Chinese with
English abstract).
Mao, J.W., Pirajno, F., Cook, N., 2011b. Mesozoic metallogeny in East China and
corresponding geodynamic settings–An introduction to the special issue. Ore Geology
Reviews 43, 1–7.
Mao, J.W., Cheng, Y.B., Chen, M.H., Pirajno, F., 2013. Major types and time–space
distribution of Mesozoic ore deposits in South China and their geodynamic settings. Miner
Deposita 48, 267–294.
Mao, J.W., Pirajno, F., Lehmann, B., Luo, M.C., Berzina, A., 2014. Distribution of porphyry
deposits in the Eurasian continent and their corresponding tectonic settings. Journal of Asian
Earth Sciences 79, 576–584.
Maruyama, S., Isozaki, Y., Kimura, G., Terabayashi, M., 1997. Paleogeographic maps of the
Japanese Islands: plate tectonic synthesis from 750 Ma to the present. The Island Arc 6,
121– 142.
Meinert, L.D., Dipple,ACCEPTED G.M., Nicolescu, S., MANUSCRIPT 2005. World skarn deposits. Economic Geology
100th Anniversary Volume, 299–336.
Mungall, J.E., 2002. Roasting the mantle: slab melting and the genesis of major Au and
Au-rich Cu deposits. Geology 30, 915– 918.
Nasdala, L., Hofmeister, W., Norberg, N., Mattinson, J.M., Corfu, F., Dörr, W., Kamo, S.L.,
Kennedy, A.K., Kronz, A., Reiners, P.W., Frei, D., Kosler, J., Wan, Y., Götze, J., Häger, T.,
Kröner, A., Valley, J.W., 2008. Zircon M257-a homogeneous natural reference material for
34 ACCEPTED MANUSCRIPT
the ion microprobe U–Pb analysis of zircon. Geostandards and Geoanalytical Research 32,
247–265.
Niu, B.G., He, Z.J., Song, B., 2003. SHRIMP dating of the Zhangjiakou volcanic series and its
significance. Geol Bull China 22, 140–141 (in Chinese with English abstract).
Pan, Z.L., Zhao, A.X., Pan, T.H., 1994. Crystallography and Mineralogy. Geological Publishing
House, Beijing, pp. 191–196 (in Chinese).
Pasteris, J.D., 1996. Mount Pinatubo volcano and “negative” porphyry copper deposits.
Geology 24, 1075–1078.
Peng, S.B., Jin, Z.M., Fu, J.M., Liu, Y.H., He, L.Q., Cai, M.H., 2006. Geochemical
characteristics of basic intrusive rocks in the Yunkai uplift, Guangdong–Guangxi, China,
and their tectonic significance. Geological Bulletin of China 25, 434–441 (in Chinese
with English abstract).
Qiu, J.T., Song, W.J., Jiang, C.X., Wu, H., Dong, R.M., 2013. CGDK: an extensible
CorelDRAW VBA program for geological drafting. Comput Geosci-UK 51, 34–48.
Ren, J.S., Chen, T.Y., Niu, B.G., Liu, Z.G., Liu, F.R., 1990. Tectonic evolution of the
continental lithosphereACCEPTED and metallogeny MANUSCRIPT in eastern China and adjacent areas. Beijing,
Sciences Press, 1-205 (in Chinese with English abstract).
Rickwood, P.C., 1989. Boundary lines within petrologic diagrams which use oxides of major
and minor elements. Lithos 22, 247–263.
Roberts, M.P., Clemens, J.D., 1993. Origin of high-potassium, calc-alkaline, I-type granitoids.
Geology 21, 825–828.
Rudnick, R.L., Mclennan, S.M., Taylor, S.R., 1985. Large ion lithophile elements in rocks
35 ACCEPTED MANUSCRIPT
from high–pressure granulite facies terrains. Geochimica et cosmochimica acta 49,
1645–1655.
Shu, L.S., Zhou, X.M., Deng, P., Yu, X.Q., 2006. Principal geological features of Nanling
tectonic belt, South China. Geological Reviews 52, 251–265 (in Chinese with English
abstract).
Silltoe, R.H., 1997. Characteristics and controls of the largest porphyry copper–gold and
epithermal gold deposits in the circum-Pacific region. Australian Journal of Earth
Sciences 44, 373–388 .
Sillitoe, R.H., 2010. Porphyry copper systems. Economic Geology 105, 3–41.
Sisson, T.W., Ratajeski, K., Hankins, W.B., Glazner, A.F., 2005. Voluminous granitic magmas
from common basaltic sources. Contributions to Mineralogy and Petrology 148,
635–661.
Sl ma, J., Košler, J., Condon, D.J., Crowley, J.L., Gerdes, A., Hanchar, J.M., Horstwood,
M.S.A., Morris, G.A., Nasdala, L., Norberg, N., Schaltegger, U., Schoene, B., Tubrett,
M.N., Whitehouse, M.J., 2008. Plesovice zircon–a new natural reference material for
U–Pb and HACCEPTEDf isotopic microanalysis. Chemical MANUSCRIPT Geology 249, 1–35.
Sun, B.D., Chen, H.C., Chen, G., 2008. Geological characteristics and metallogenic regularity
of Shilu copper deposit,Yangchun in Guangdong province. West-China Exploration
Engineering 5, 106–109 (in Chinese with English abstract).
Sun, S.S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts:
implication for mantle composition and processes. In: Sauders, A.D., Norry, M.J. (Eds.),
Magmatism in the Ocean Basin, Geol. Soc. Spec. Pub. 42, pp. 313–345.
36 ACCEPTED MANUSCRIPT
Sun, W.D., Arculus, R.J., Kamenetsky, V.S., Binns, R.A., 2004. Release of gold-bearing fluids
in convergent margin magmas prompted by magnetite crystallization. Nature 431,
975–978.
Taylor, S.R., Mclennan, S.M., 1995. The geochemical evolution of the continental-crust.
Reviews of geophysics 33, 241–265.
Urich, T., Guenther, D., Heinrich, C.A., 1999. Gold concentrations of magmatic brines and
the metal budget of porphyry copper deposits. Nature 399, 676–679.
Wang, Y.J., Fan, W.M., Guo, F., 2002. K–Ar dating of late Mesozoic volcanism and
geochemistry of volcanic gravels in the North Huaiyang belt, Dabie orogen: constraints on
the stratigraphic framework and exhumation of the northern Dabie orthogenesis complex.
Chinese Sci Bull 47, 1528–1534 (in Chinese with English abstract).
Whalen, J.B., Currie, K.I., Chappell, B.W., 1987. A-type granites: geochemical characteristics,
discrimination and petrogenesis. Contributions to Mineralogy and Petrology 95, 407–419.
Whalen, J.B., Chappell, B.W., 1988. Opaque mineralogy and mafic mineral chemistry of I-
and S-type granites of the Lachlan fold belt, southeast Australia. American Mineralogist
73, 281–296ACCEPTED . MANUSCRIPT
Wones, D.P., Eugeter, H.P., 1965. Stability of biotite: experiment, theory, and application. The
American Mineralogist 50, 1228–1272 .
Wu, J., Zeng, X.H., 2011. Geological characteristics of Nanshan Bengkeng–Shiwu Lead–zinc–
copper–tin deposit in Yangchun City, Guangdong Province. Resources environment and
engineering 25, 201–208 (in Chinese with English abstract).
Xie, G.Q., Mao, J.W., Zhou, S.D., Ye. H.S., Yan, Q.R., Zhang, Z.S., 2006. SHRIMP zircon
37 ACCEPTED MANUSCRIPT
U–Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province,
middle–lower reaches of the Yangtze River and its implications. Chinese Sci Bull 51,
3000–3009 (in Chinese with English abstract).
Xu, L.G., Mao, J.W., Yang, F.Q., Hennig, D., Zheng, J.M., 2010. Geology, geochemistry and
age constraints on the Mengku skarn iron deposit in Xinjiang Altai, NW China. Journal
of Asian Earth Sciences 39, 423–440.
Yu, J.S., Gui, X.T., Li, P.Z., 1988. The research on iosotpe and trace element geochemistry of
granitoids in Yangchun basin, Guangdong province. Guangdong geology 13, 1–10 (in
Chinese with English abstract).
Yu, Z.F., Mao, J.W., Zhao, H.J., Chen, M.H., Luo, D.L., Guo, M., 2012. Geological
characteristics and ages of granites and related mineralization in the Dajinshan tungsten–tin
polymetallic deposit, western Guangdong Province. Acta Petrologica Sinica 28, 3967–3979
(in Chinese with English abstract) .
Yuan, S.D., Peng, J.T., Hu, R.Z., Li, H.M., Shen, N.P., Zhang, D.L., 2008. A precise U–Pb age
on cassiterite from the Xianghualing tinpolymetallic deposit (Hunan, South China).
Mineralium DepositaACCEPTED 43, 375–382. MANUSCRIPT
Yuan, S.D., Peng, J.T., Hao, S., Li, H.M., Geng, J.Z., Zhang, D.L., 2011. In situ
LA–MC–ICP–MS and ID–TIMS U–Pb geochronology of cassiterite in the giant Furong tin
deposit，Hunan Province，South China: New constraints on the timing of tin–polymetallic
mineralization. Ore Geology Reviews 43, 235–242.
Yuan, S.D., Zhang, D.L., Shuang, Y., Du, A.D., Qu, W.J., 2012. Re–Os dating of molybdenite
from the Xintianling giant tungsten-molybdenum deposit in southern Hunan Province,
38 ACCEPTED MANUSCRIPT
China and its geological implications. Acta Petrologica Sinica 28, 27–38 (in Chinese with
English abstract).
Zhai, Y.S., Deng, J., Li, X.B., 1999. Essentials of metallgeny. China University of Geoscience
Press, Wuhan, pp. 1–286 (in Chinese).
Zhang, X.Q., 2008. The discuss on genetic type and mineralization of Shilu Cu–Mo deposit in
Yangchun basin. Chemical Engineering and equipment 10, 62–65 (in Chinese with English
abstract).
Zhang, Z.Y., Du, Y.S., Zhang, J., Pang, Z.S., Li, D.P., Jia, P.F., 2010. Alteration and
mineralization zoning in Tongshan skarn-type copper deposit in Guichi, Anhui Province,
and its genesis. Mineral Deposits 29, 999–1016 (in Chinese with English abstract).
Zhao, H.J., Mao, J.W., Xiang, J.F., Zhou, Z.H., Wei, K.T., Ke, Y.F., 2010. Mineralogy and
Sr–Nd–Pb isotopic compositions of quartz diorite in Tonglushan deposit, Hubei Province.
Acta Petrologica Sinica 26, 768–784 (in Chinese with English abstract).
Zhao, H.J., Zheng, W., Yu, Z.F., Hu, Y.G., Tian, Y., 2012. Re–Os dating of molybdenite from
the Shilu Cu(Mo) deposit in western Guangdong Province and its geological
implications.ACCEPTED Geology in China 39, 1604 MANUSCRIPT–1613 (in Chinese with English abstract).
Zhao, Z.J., Ma, D.Q., Lin, H.K., Zhang, X.H., 1985. Rb–Sr and O isotope characterisitic and
genesis of two tpye granites in Yangchun distict, Guangdong province. Bulletin of the
YiChang Institute of Geology and Mineral Resources Chinese Academy of Geological
Sciences 10, 89–97 (in Chinese).
Zheng, W., Chen, M.H., Xu, L.G., Zhao, H.J., Ling, S.B., Wu, Y., Hu, Y.G., Tian, Y., Wu,
X.D., 2013a. Rb–Sr isochron age of Tiantang Cu–Pb–Zn polymetallic deposit in
39 ACCEPTED MANUSCRIPT
Guangdong Province and its geological siginificance. Mineral deposits 32, 259–272 (in
Chinese with English abstract).
Zheng, W., Zhao, H.J., Chen, M.H., Xu, L.G., Liu, J.X., Luo, D.L., Hu, Y.G., 2013b. Re–Os
isotopic dating of molybdenites from the Yingwuling polymetallic deposit in Guangdong
Province and its geological significance. J. Mineral Petrol 33, 38–46 (in Chinese with
English abstract).
Zheng, W., Chen, M.H., Zhao, H.J., Zhao, C.S., Hou, K.J., Liu, J.X., Li, X.M., Chang, L.Z.,
2013c. Zircon U–Pb geochronological and Hf isotopic constraints on petrogenesis of
Yingwuling tungsten polymetallic deposit in Guangdong Province and its geological
significance. Acta Petrologica Sinica 29, 4121–4135 (in Chinese with English abstract).
Zhou, Z.X., 1986. The origin of intrusive mass in Fengshandong, Huibei Province. Acta
Petrologica Sinica 2, 59–70 (in Chinese with English abstract).
Zhou, X.M., 2007. Petrogenesis of Late Mesozoic granitoids in the Nanling region and
dynamical evolution of the lithosphere. Science Publishing House, Beijing, pp. 1–691 (in
Chinese). ACCEPTED MANUSCRIPT
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Figure Captions
Fig. 1 (a) Simplified geological map showing the spatial and temporal distribution of
Mesozoic porphyry-skarn copper deposits in eastern China (after Mao et al., 2014), (b) Sketch geological map of the Yunkai area (after Peng et al., 2006), (c) Geological map and cross section of the Shilu Cu–Mo deposit (after Zhao et al., 2012).
Fig. 2 Hand specimens and photomicrographs of granodiorite from the Shilu deposit.
(a) Hand specimens of granodiorite with little alteration; (b) Endoskarn; (c) Exoskarn; (d)
Granodiorite showing quartz and plagioclase with a zoned texture (crossed polarized light); (e)
Euhedral hornblende (crossed polarized light); (f) Biotite and the K-feldspar in the granodiorite (crossed polarized light). Abbreviations: Qz = Quartz, Bt = Biotite, Kf =
K-feldspar, Pl = Plagioclase, and Hb = Hornblende.
Fig. 3 Classification diagram of feldspars (after Pan et al., 1994)
Fig. 4 Classification diagrams for (a) biotites (after Foster, 1960) and (b) for amphiboles (after
Leake et al., 1997). ANa + AK﹤0.5, Ti ﹤0.5.
Fig. 5 Representative cathodoluminescence (CL) images of zircons from the Shilu granodiorite. CirclesACCEPTED indicate locations of MANUSCRIPT analyzed sites, with numbers in the circles representing for spot numbers. The 206Pb/238U age for each spot is given.
Fig. 6 LA–ICP–MS zircon U–Pb concordia diagram of the Shilu granodiorite.
Fig. 7 (a) K2O versus SiO2 diagram for representative rocks from the Shilu granodioritic intrusion (fields in the plot are from Rickwood, 1989) (b) A/NK versus A/CNK{A/NK = molar ratio of [Al2O3/(Na2O + K2O)]; A/CNK = molar ratio of [Al2O3/(CaO + Na2O + K2O)]}
Fig. 8 (a) Chondrite-normalized REE patterns (after Boynton, 1984)
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(b) Primitive-mantle-normalized spider diagrams (after Sun and McDonough, 1989)
Fig. 9 Harker diagrams for selected major and trace elements of the Shilu granodiorite
Fig.10 (a) Plots of (a) (K2O + Na2O)/CaO versus Zr + Nb + Ce + Y (after Whalen et al., 1987)
(b) Plots of La/Yb vs. La of the Shilu granodiorite (c) Plots of Ba/Rb vs. Rb/Sr of the Shilu granodiorite (after Furman and Graham, 1999). FG = Fractionated M-, I- and S-type felsic granites; OGT = non-fractionated M-, I- and S-type granites.
Fig. 11 (a) Nb versus Y, (b) Rb vs. (Y + Nb), (c) Rb versus (Yb + Ta) and (d) Ta vs. Yb diagrams (after Pearce et al., 1984). ORG = oceanic ridge granite; VAG = volcanic arc granite; syn-COLG = syn-collision granite. WPG = within plate granites
Fig.12 (a) Plots of (La/Yb)N vs. δEu of the Shilu intrusion (b) Plot of TiO2 versus Al2O3 for hornblendes (after Jiang and An, 1984) (c) Plot of ∑FeO/(∑FeO + MgO) versus MgO for biotites (after Zhou, 1986)
87 86 Fig. 13 Diagrams of (a) εNd(t) versus age (b) n( Sr)/n( Sr)i versus εNd(t) (after Zhou, 2007 and references herein)
Fig.14 (a) Plot of coexisting amphibole-biotite to pressure (after Lin and Yin, 1998) (b) Plot of Ti versus Mg/(MgACCEPTED + Fe) for biotites (after MANUSCRIPTHenry et al., 2005)
Fig.15 Ternary Fe3+–Fe2+–Mg2+ plot for biotites (after Wones and Eugeter, 1965)
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Table Caption
Table 1 Electron microprobe analyses of selected plagioclases (wt%) for the Shilu granodiorite
Table 2 Electron microprobe analyses of selected K-feldspars (wt%) for the Shilu intrusion
Table 3 Electron microprobe analyses of selected biotites (wt%) for the Shilu granodiorite
Table 4 Electron microprobe analyses of selected hornblendes (wt%) for the Shilu granodiorite. Calculations based on 8, 22, and 24 oxygen anions for plagioclace and
K-feldspar, biotite, and hornblendes, respectively
Table 5 LA–ICP–MS U–Pb results of zircons form the Shilu granodiorite
Table 6 Major (in wt.%), trace and rare earth element (in ppm) compositions of the Shilu granodiorite
Table 7 Sr–Nd isotopic compositions of the Shilu granodiorite
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Figure 5
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Figure 6
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Figure 13
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Figure 15
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Table 1
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Table 2
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Table 3
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Table 4
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Table 5
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Table 7
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Highlights
(1)Plagioclase is primarily andesine, biotite and hornblende is mainly Mg-rich. (2)Rock minerals thermobarometry constrain intrusions as 686–780℃ and 1.0–2 kbar. (3)The magmatism and timing of mineralization fell into Early Cretaceous(107Ma). (4)The Shilu intrusions are calc-alkaline rocks and parent magmas are mixed-source. (5)The formation of Shilu deposit was formed in an extensional environment, and closely related to the subduction of Pacific plate.
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