Journal of Earth Science  2018, Vol. 29 Issue (4): 939-959   PDF    
0
Petrogenesis and Ore Genesis of the Late Yanshanian Granites and Associated Porphyry-Skarn W-Mo Deposits from the Yunkai Area of South China:Evidence from the Zircon U-Pb Ages, Hf Isotopes and Sulfide S-Fe Isotopes
Xinyu Wang1,2, Zhen Yang3, Nengsong Chen1, Rui Liu3    
1. School of Earth Sciences, China University of Geosciences, Wuhan 430074, China;
2. Geological Prospecting Institute of Guangxi Zhuang Autonomous Region, Nanning 530023, China;
3. Faculty of Earth Resources, China University of Geosciences, Wuhan 430074, China
ABSTRACT: There are a wide range of magmatism and mineralization in the Yunkai area of South China during the Late Yanshanian Period, including the newly discovered Michang, Youmapo, Sanchachong and Songwang porphyry-skarn W-Mo deposits. In this study, we obtained zircon U-Pb ages of the ore-bearing biotite granites and their mafic enclaves from 88±1 to 110±1 Ma. Zircons from the granites show Hf isotopic compositions with negative εHf(t) values of -5.9 to -0.6 and calculated Hf model ages (TDM2) of 1.5-1.2 Ga; indicating that the Middle Proterozoic crustal materials may have provided an important source for the magmatic rocks in this district during the Late Yanshanian Period, whereas zircons from the mafic enclaves show positive εHf(t) values of 1.3 to 10.1 with younger Hf model ages (TDM2) of 0.5-1.1 Ga, suggesting a mantle component may have involved in the granitic magma generation. Sulfur isotope study of the sulfide minerals from the W-Mo deposits show a narrow δ34S distribution with most data ranging from -4.2‰ to 5.2‰. In addition, this study reports the first Fe isotopic compositions of pyrite in the W-Mo deposits, which show a uniform distribution range with the values near zero (δ56Fe=0.16‰-0.58‰, average 0.35‰; δ57Fe=0.02‰-0.54‰, average 0.48‰). These data indicate that the ore-forming materials may come from the deep-sourced granitic magma, and the mineralizations show a close relationship with the granitic magmatism during the Late Yanshanian Pe-riod. Combining with previous results, we suggest that there is a widespread porphyry-skarn W-Mo mineralization in the Yunkai area during the Late Cretaceous (80-110 Ma), which has a close relation-ship with the Late Yanshanian magmatism that may have formed during the rollback of the subducted Pacific Plate.
KEY WORDS: zircon U-Pb age    Hf isotopes    S-Fe isotopes    granitic magmatism    Late Yanshanian    Yunkai area    

0 INTRODUCTION

The South China Block has experienced a complicated tectono-magmatic-mineralization history during the Late Yanashanian Period, with widespread multiple-stage granitic rocks (Fig. 1a) and associated Cu-Au-Pb-Zn-Ag and W-Sn-Mo ore deposits (Li and Jiang, 2016; Li et al., 2016; Jiang et al., 2013; Mao et al., 2011, 2008; Yang et al., 2011; Li and Li, 2007; Zhou et al., 2006). It has become one of the most important tungsten mining areas in China or even in the world. Mao et al. (2008) put forward a three-stage formation model for the South China tungsten deposits, namely, the Triassic (230–210 Ma), Jurassic (170–150 Ma) and Cretaceous (134–80 Ma) stages. It is noted that the Triassic tungsten mineralization is less important, with only a few tungsten-tin polymetallic deposits, such as those in the Gannan, Chongyi, and Dayu ore-concentrated areas in the Exian Tang tin-tungsten mineralization belt (Liu et al., 2008). The Jurassic metallogenesis is one of the most important metallogenic events in South China, and this time is also the main metallogenic period of tungsten. The main ore deposit types in this period include skarn-type and quartz-vein-type and a small amount of greisen-type. In recent years a large number of high-precision geochronology studies were carried out for this region's main tungsten-tin deposits and the ore-bearing granitic rocks, including the Shizhuyuan, Yaogangxian and Xintianling deposits in southern Hunan Province; the Taoxikeng, Dajinshan deposits in Jiangxi Province; the Shirenzhang deposit in northern Guangdong Province, and the Xingluo deposit in Fujian Province. Previous results showed that the major tungsten-tin mineralization took place between 165 and 150 Ma (Guo et al., 2012; Zhao et al., 2012, 2006; Chen M H et al., 2011; Fu et al., 2011; Chen F W et al., 2008; Jiang et al., 2008, 2006; Mao et al., 2008).

Download:
Figure 1. Simplified geological map showing the Yanshanian granitoids in the southeastern South China Block and the Precambrian basement in the Cathaysia Block (a) and simplified geological map of the Yunkai area (b).

Yunkai area is a typical area in South China where developed Caledonian Orogeny (Wang et al., 2012, 2007), with widespread occurrence of Caledonian (Kwangsian) granites (Fig. 1b). The Yanshanian mineralization is the most important metallogenic event in the Yunkai area, with important Ag-Au polymetallic mineralization of Early Yanshanian such as the Yakeng and Chengcu deposits; and the Pb-Zn-Au-Ag deposits of Late Yanshanian such as the Fuzichong Pb-Zn-Ag deposit and the Jinshan Au deposit. In recent years, new tungsten- molybdenum (tin) deposits have been discovered in the Youmapo, Sanchachong, Michang, and Songwang (Fig. 2), which shows good potentials for tungsten-molybdenum ore prospecting in this region.

Download:
Figure 2. Geological map of the Yunkai area showing the distribution of W-Mo deposits.

The tungsten-molybdenum deposits from the Yunkai area show large differences from the other parts of South China in the formation ages and their spatial distribution. In this region, the tungsten-molybdenum mineralization shows a close relationship to the large magmatic activity during the Late Yanshanian, in contrast to the Middle Yanshanian in other parts of South China (Yang et al., 2014). Therefore, the study of typical porphyry-skarn type tungsten-molybdenum deposits in the Yunkai area has important scientific significance to a better understanding of the Late Yanshanian magmatism and mineralization in the area.

In this study, we focuse on the newly discovered Youmapo tungsten-molybdenum deposit, Sanchachong tungsten deposit, Michang tungsten-molybdenum deposit, Songwang tungsten tin (-molybdenum) deposit. On the basis of field geological investigation and petrography study, we carried out a detailed study of zircon U-Pb dating and Hf isotopes, and sulfide S-Fe isotope geochemistry, in an effort to reveal the ore deposit characteristics, fluid properties and the source of ore-forming materials. These data can provide further constraints on the spatial and temporal distribution patterns of the granitic magmatism and associated mineralization in South China during Late Yanshanian, and it will also provide a scientific basis for guiding future prospecting exploration in the region.

1 REGIONAL GEOLOGIC SETTING

Yunkai area is located in the southwest of South China Block (Fig. 1). Since the Early Paleozoic, the area was strongly influenced by the Caledonian Orogeny, Indosinian Orogeny and Yanshanian tectono-magmatic activity, with occurrence of granites in different ages and associated mineral deposits (Wang Y J et al., 2013, 2012, 2011; Zhang et al., 2012; Wan et al., 2010; Li Z X et al., 2009; Ling et al., 2006; Deng et al., 2004). As a result, the Yunkai area is not only located in the southwest of "Wu Yun" Caledonian orogenic belt in South China (Li et al., 2010), but also is located in the southwest of the famous "Qin Hang metallogenic belt" (Mao et al., 2011).

The Bobai-Cenxi fault and Wuchuan-Sihui fault divided the Yunkai area into three units, namely, the Southeast Guangxi, Yunkai and Middle Guangdong units. According to the characteristics of the rock assemblage and metamorphic deformation, the rocks of Yunkai area can be divided into two units: the upper part is mainly metamorphic volcanic-sedimentary formation with a set of greenschist facies (locally up to epidote- amphibolite facies), called the Yunkai Group; the lower part includes metamorphic rocks and intruded gneissic, ribbon, and eye (spot) ball shaped granitic rocks (including charnockite) up to amphibolite-granulite facies, which outcropped in Xinyi and Gaozhou area, known as Xinyi-Gaozhou complex rock (Wang et al., 2013; Chen et al., 2012; Peng et al., 2006). The lower lithology of Yunkai Group consists of mainly metamorphic arkose, mica-quartz schist, mica quartzite, garnet-mica-quartz schist, quartzite (siliceous rocks), with interbedded actinolite-diopside rock, metabasite (metagabbro, basalt and plagioclase amphibolite, etc.), banded magnetite layer, phosphate rock layer, and dolomitic marble layer. The lower unit of the Yunkai Group has a thickness > 1 307 m. The upper lithology of the Yunkai Group consists of mainly metamorphosed siltstone, quartz-sericite phyllite, siliceous rock, granet-bearing quartz schist, with thickness > 1 343 m (Peng et al., 2006). In addition, there are a lot of Caledonian-to-Yanshanian Period granitic rocks distributed in the Yunkai area.

2 GEOLOGY OF THE PORPHYRY-SKARN DEPOSITS

The tungsten-molybdenum deposits in the Yunkai area are mainly located within the Bobai-Cenxi fault zone in the southeastern Guangxi Province, which belongs to the southern section of the Qin Hang metallogenic belt. This fault zone is also an important boundary fault, which separates Yunkai land to the southeast and the Bobai depression to the northwest (Zhou et al., 2015; GGST, 1986). As one of the important boundary faults in South China, this fault zone has experienced several tectonic movements and magmatic activities in the process of geologic evolution history. Since Caledonian Orogeny, this district has experienced multiple stage compression and extension. Especially during the Late Yanshanian stage occurred regional extension and large-scale magmatic activities with associated mineralization events, which formed a W-Mo-Sn-Pb-Zn-Ag polymetallic metallogenic belt (Mao et al., 2008; Chen et al., 1990). A number of large- and medium- sized skarn-type tungsten-molybdenum deposits occurred in the southwest segment of the fault zone, including the Youmapo tungsten-molybdenum deposit, the Andong tungsten- molybdenum deposit, the Sanchachong tungsten-molybdenum deposit, the Michang (Liusu, Mocun) tungsten-molybdenum deposit, and the Songwang tungsten-tin deposit (Tang, 2009; Zhong and Huang, 2007; Ye, 2005). All of these deposits have close relationship with granitic magmatism.

The Youmapo tungsten-molybdenum deposit is located in the northeast of Bobai County, about 20 km away from the Xiuling Village of Jingkou Town. The outcropped rocks include the Silurian and Devonian system formations in the mining area. The major thrust fracture in the mining area shows an NE-extending, with the secondary fault trending NW. The Youmapo granodioritic stock occurs in the southeast of the mining area, with an outcrop of about 1.3 km2, which intruded into the Silurian and Devonian strata. Porphyritic and skarn mineralization occurred near the Youmapo granodioritic body and in the contact zone between the granodiorite and the host carbonate rock. The tungsten mineralization took place with the formation of skarn alteration. Part of the ore body formed within fractures of the granodioritic rock, with the form of molybdenite-quartz veins. The ore minerals include scheelite, molybdenite, bismuthinite, chalcopyrite, sphalerite, pyrite, marcasite, pyrrhotite and a small amount of wolframite and trace amount of natural gold. The gangue minerals are mainly garnet, quartz, calcite, fluorite; with minor amounts of actinolite, epidote, diopside, chlorite, plagioclase and white mica. The skarn minerals include garnet, diopside, actinolite, epidote, and chlorite. The alterations associated with the vein-type mineralization include mainly silicification, potassium alteration, chloritization, and sericitization.

The Sanchachong tungsten deposit is located in the southwest section of the Bobai-Wuzhou fault zone. This is mainly a skarn-type tungsten deposit, which also contains minor molybdenum (Ye, 2005). The outcropped rocks in the mining area include the Ordovician and Devonian strata, including sandstone, limestone and argillaceous siltstone, which have all turned into schists during regional metamorphism. The major fault is the NE-trending compressive shear fault. Magmatic rock occurring in the mining area is mainly the biotite granite. Ore bodies are found mainly in the outer skarn contact zone in the Ordovician formation of the fourth period of Dongchong Group, which were controlled by fault. The shapes of the ore bodies include bedded and lenticular. Ore minerals include mainly scheelite, wolframite, pyrite, chalcopyrite, limonite, and cassiterite. The gangue minerals are quartz, chlorite, epidote, garnet, and mica. Alterations include skarnication, silicification, pyritization and greisenization.

The Michang tungsten-molybdenum deposit is located about 10 km from the Michang County. Ore bodies occur in the contact zone between the Michang granite and the Ordovician Huangai Group of marble, quartz schist, and gneiss. The Michang granitoid rocks of mainly biotite granite and granodiorite show a medium-coarse grained structure, which can be divided into two phases (internal phase and marginal phase). In the marginal facies, the phenomenon of hybrid can be seen. There are two major types of the ores, one is the tungsten- molybdenum ore associated with garnet skarn and the other is the tungsten ore associated with hornblende-epidote quartzite. Ore minerals include scheelite, molybdenite, pyrite and chalcopyrite. The gangue minerals are mainly of garnet, quartz, chlorite, calcite, hornblende, and epidote.

The Songwang tungsten-molybdenum-tin deposit in the Bobai Town is located in the southwest end of the Dongtao anticline, which is in the southeast of the Luchuan-Cenxi deep fault (Tang, 2009). The outcropped rocks include Early Palaeozoic migmatites and Middle–Lower Devonian low-grade metamorphic rocks. The fault systems in the mining area include mainly the SN-trending fault and secondarily the EW-trending fault. Magmatic rocks are widely distributed in the mining area, including mainly the Songwang fine-grained biotite granite and the Guogailing porphyritic granite.

Orebody occurs mainly within the Guogailing porphyritic granite and its contact zone with the augen migmatite in the layered and lenticular form. The orebody is mainly controlled by structural fractures of NE direction. The mineralization is mainly Mo, followed by W and Sn mineralization. Ore minerals include mainly molybdenite, followed by wolframite, cassiterite, pyrite, pyrrhotite, chalcopyrite, galena, sphalerite, columbite- tantalite, and ilmenite. The gangue minerals are plagioclase, potassium feldspar, quartz, biotite, sericite, white mica, and chlorite, with minor amounts of tourmaline and fluorite.

The alterations are mainly silicification, potassium feldspathization, greisenization, topazization, sericitization, followed by chloritization and pyritization. The silicification, potassium feldspathization and greisenization show a close relationship with the mineralization.

3 SAMPLE DESCRIPTION AND ANALYSIS METHOD 3.1 Sample Description

The studied samples are collected from four typical porphyry and skarn-type deposits including the Michang, Youmapo, Sanchachong, and Songwang in the western region of the Yunkai area. Five granite samples and one mafic enclave in the granite (Fig. 3) are used for zircon U-Pb age and Hf isotopic analysis (Fig. 4), and twelve samples of pyrite, pyrrhotite, galena and sphalerite are selected for S-isotope analysis (Fig. 7) and eleven pyrite samples are selected for Fe isotope analysis (Fig. 8).

Download:
Figure 3. Field geological, sample and microscopic characteristics of the representative Late Yanshanian granites from the porphyry-skarn W-Mo deposits in the Yunkai area. Bt. biotite; Kfs. K-feldspar; Qz. quartz; Amp. amphibole; Pl. plagioclase.
Download:
Figure 4. Representative cathodoluminescence (CL) images of zircons of granite samples from the porphyry-skarn W-Mo deposits in the Yunkai area. Round circles (solid line) with 32 μm diameter indicate the spots of LA-ICP-MS analyses with the 206Pb/238U age and spot numbers being labeled nearby.
Download:
Figure 7. δ34S histograms of sulfides from the porphyry-skarn W-Mo deposits in the Yunkai area.
Download:
Figure 8. Iron isotope compositions comparing this study (colored symbols represent samples measured), with sea water, Fe-Mn noudle, mid-ocean ridge, BIF, igneous rock and mantle xenolith.

Among them, samples MC03, MC10 and GT02 are collected from the Michang tungsten-molybdenum deposit. Sample MC03 is a biotite granite, which consists mainly of potassium feldspar (~40%), plagioclase (~20%), quartz (~25%) and biotite (~10%). Accessory minerals include mainly magnetite, apatite, sphene and zircon. Sample MC10 is a mafic enclave in the Michang biotite granite, which shows a porphyritic structure and has a dioritic composition. The main minerals are plagioclase (~40%), potassium feldspar (~5%), quartz (~4%), hornblende (~35%), and biotite (~15%), with a small amount of accessory minerals such as sphene, zircon and apatite (~1%). Sample GT02 is a biotite granite, consisting of potassium feldspar (~40%), plagioclase (~15%), quartz (~30%) and biotite (~10%). Accessory minerals include mainly apatite and zircon (a total of ~5%). Sample SY03 is a biotite granite from the Youmapo tungsten-molybdenum deposit, consisting of potassium feldspar (~42%), plagioclase (~23%), quartz (~25%) and biotite (~10%). Accessory minerals include apatite and zircon (a total of ~5%). Locally, chloritization occurred in this rock.

Sample SC07 is a biotite granite from the Sanchachong tungsten-molybdenum deposit. The main minerals are potassium feldspar (~40%), plagioclase (~18%), quartz (~32%) and biotite (~8%). Apatite, titanite and zircon (a total of ~2%) are mainly accessory minerals. Locally, chloritization also occurred in this rock.

Sample SW08 is a granite-porphyry from the Songwang tungsten-molybdenum-(tin) deposit. The main minerals are potassium feldspar (~45%), plagioclase (~20%), quartz (~30%) and biotite (~3%). Apatite, titanite and zircon (a total of ~2%) are the main accessory minerals.

3.2 Methods 3.2.1 Zircon U-Pb age and Hf isotope

Zircon samples were separated using the method of heavy liquid and magnetic separation technology, and then handpicked under a binocular microscope according to crystal shape, color and transparency. Selected zircon grains were mounted in an epoxy disc and polished to expose the interiors. The morphology and internal structure of zircons were characterized by optical microscopy and cathodoluminescence (CL) imaging using a Mono CL3+ (Gatan, USA) detection system in the Scanning Electron Microscopy Laboratory of Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing.

Zircon U-Pb isotope dating was completed in the State Key Laboratory of Geological Processes and Mineral Resources (GPMR) of China University of Geosciences (Wuhan) used LA-ICP-MS analysis mothod with GeoLas 2005 for Laser ablation system, Agilent 7500a for ICP-MS. Laser ablation process using helium as a carrier gas, argon as compensate gas to adjust the sensitivity, through a T-shape joint to mixture before them entering the ICP. Adding a small amount of nitrogen in the center of the plasma gases (Ar+He), can be effective to enhance the sensitivity, lower detection limit and improve the analysis precision (Hu et al., 2008a).

The resolution of analysis data includes about 20–30 s blank signal and 50 s sample signal in each time. Offline processing for the data analysis (including the selection of sample and the blank signal, the sensitivity drift correction, element content, U-Th-Pb isotope ratio and age calculation) using the software of ICPMSDataCal (Li et al., 2010; Liu et al., 2008). The detailed instrument operating conditions and the method of data processing are arranged according to Liu R et al. (2010). U-Pb isotope dating using isotopic fractionation of zircon standard 91500 as external standard calibration, two times 91500 analysis when each of five sample points analysis has been done. For U-Th-Pb isotope ratios drift related to the analysis time, using the way of linear interpolation of the 91500 changes for calibration (Li et al., 2010). U-Th-Pb isotope ratio of the Zircon standard 91500 is in accordance with the recommended Wiedenbeck et al. (1995). Zircon sample's U-Pb age harmonic mapping and weighted average age calculation were completed by using Isoplot/Ex_ver3 (Ludwig, 2003).

The test of zircon Hf isotope ratios in situ micro zone by laser ablation of receiving more cups of plasma masss pectrometry (LA-MC-ICP-MS) was completed in the State Key Laboratory of Processes and Mineral Resources (GPMR), China University of Geosciences (Wuhan). The system of Laser ablation is GeoLas 2005 (Lambda Physik, Germany), the MC-ICP-MS is Neptune Plus (Thermo Fisher Scientific, Germany). The system is equipped with the signal smoothing device which is research independent and developed by laboratory. Even if the laser pulse frequency declines to 1 Hz, device still can obtain steady signal (Hu et al., 2012a). For the 100 and 93 nm laser, under the condition of a given instrument, using the helium as a carrier gas is two times higher than using the argon gas in signal sensitivity (Hu et al., 2008b). Research also suggests that the sensitivity of most elements can be further enhanced when it introduces a small amount of nitrogen (Hu et al., 2008a). Relative to the standard cone combination of Neptune Plus, a new design of X intercept cone combination and Jet sampling cone combination can improve the Hf, Yb and Lu sensitivity respectively 5.3 times, 4.0 times and 2.4 times under the condition of a small amount of nitrogen to joined. The laser output power can be adjusted, and the actual output energy density is 5.3 J/cm2. Adopts the model is single point denudation, the spot beam fixed at 44 μm. Details of analysis method and conditions about instrument can refer to Hu et al. (2012b).

The major limitation to accurate in situ zircon Hf isotope determination by LA-MC-ICP-MS is the very large isobaric interference from 176Yb and, to a much lesser extent 176Lu on 176Hf. Research shows that the quality of Yb fractionation factor (βYb) is not a fixed value in the process of testing for a long time. The βYb of the zircon Hf isotopic interference correction by testing in sample solution way does not apply to the laser sample pattern (Woodhead et al., 2004). The βYb error estimation will significantly affect 176Yb interference correction to 176Hf, and futher affect 176Hf/177Hf ratio accurate determination. In this experiment, we obtained the zircon sample's βYb for interference correction. 179Hf/177Hf=0.732 5 and 173Yb/171Yb= 1.130 17 (Segal et al., 2003) were used to calculate the βHf and βYb quality fractionation factor of Hf and Yb. 179Hf/177Hf and 173Yb/171Yb ratios were used to calculate Hf (βHf) and Yb (βYb) the quality of the deviation. Deduct 176Yb commensuration ectopic interference to 176Hf by using the 176Yb/173Yb=0.793 81 (Segal et al., 2003). Deduct the relatively small disturbance of 176Lu commensuration ectopic interference to 176Hf by using the 176Lu/175Lu=0.026 56 (Blichert-Toft et al., 1997).

As Yb and Lu have similar physical and chemical properties, we use the βYb quality fractionation factor of Yb to correct Lu quality fractionation behavior in this experiment. The analysis of data's off-line process was accomplished (including the sample and the blank signal selection, isotope quality fractionation correction) using software ICPMSDataCal (Liu X H et al., 2010), εHf(t) was calculated with 176Lu decay constant of 1.865×10-11 a-1 (Scherer et al., 2001), the present-day chondritic ratios of 176Hf/177Hf=0.282 772 and 176Lu/177Hf=0.033 2 (Blichert-Toft et al., 1997). Hf model age (TDM1) of depleted mantle calculated using current depleted mantle 176Hf/177Hf=0.283 25 and 176Lu/177Hf=0.038 4 (Griffin et al., 2000). Hf model age (TDM2) of the two-phase calculated using an average of continental crust 176Lu/177Hf=0.015 (Griffin et al., 2002).

3.2.2 Sulfide S and Fe isotopes

Pyrite and pyrrhotite are predominant sulfide minerals accompanied with the W-Mo mineralization, and were collected in the Sanchachong, Songwang and Sanyu deposits, to analyze the sulfide sulfur isotopic (n=11) and iron isotopic (n=12) geochemistry. S isotope test was accomplished at the Isotope Laboratory University of Arizona in the United States (Environmental Isotope Laboratory, University of Arizona). Samples after crushing, oscillation, washing one hour and drying in the ultrasonic cleaning machine, differently selected sulfide mineral grains 0.5 g of pyrite, pyrrhotite, galena and sphalerite under the binocular microscope. Pyrite and other sulfides heating to 1 150 ℃ under the condition of high vacuum, SO2 were extracted with Cu2O as oxidant, frozen the release of SO2 with liquid nitrogen into the charge for mass spectrometry analysis. Isotope values expression with the ratio micrometer difference of sample (A) and the corresponding standard R, says that δMA=[(RARStd)/RStd]×100 (type of R=(S34/S32); M=S34; RStd is the reference standard ratio, sulfur isotope standard using V-CDT). Average analysis error of delta value, sulfur is ±0.2‰. The test of Fe isotope work accomplishes in Center of the Water Environment of Canada Trent University (Water Quality Centre, Trent University, Canada).

4 RESULTS 4.1 U-Pb Ages 4.1.1 Michang biotite granites and mafic enclaves

Zircon grains are mostly colorless and transparent in Sample MC03 of Michang biotite granite, part is dark brown. The size of zircon grains ranges in 50–300 μm, and the length to width ratios are between 1: 1 and 5: 1. In the cathodoluminescence (CL) images (Fig. 4, MC03), almost all the zircons show typical rhythmic oscillation zoning, indicating magmatic origin. In addition, small amounts of zircons show obvious core-rim structures. According to the U-Pb dating of eighteen zircon grains of MC03 (Table 1, Fig. 5, MC03), the 206Pb/238U ages are between 107 and 113 Ma, with a weighted mean 206Pb/238U age of 110±1 Ma (MSWD=2.0), and this age may represent the emplacement age of the Michang biotite granite. In sample MC10 of the mafic enclaves in the biotite granite, zircon grains are mostly colorless and transparent, and part is tan. The grain size ranges in 30–200 μm, and the length to width ratios are between 1: 1 and 5: 1. In the cathodoluminescence (CL) images (Fig. 4, MC10), most zircon grains display patch-shaped band, planar band or band, and a handful of zircon grains show rhythmic oscillation zoning. In addition, small amounts of zircon grains show also core-rim structures. Fourteen zircon U-Pb dating results yield 206Pb/238U ages between 106 and 112 Ma, with a weighted mean 206Pb/238U age of 109±1 Ma (MSWD=1.8) (Table 1, Fig. 5, MC10). A spot analysis also points to an inherited zircon in this sample with a 206Pb/238U age of 194±6 Ma.

Table 1 LA-ICP-MS U-Pb data for zircons from the Late Yanshanian granites from the porphyry-skarn W-Mo deposits in the Yunkai area
Download:
Figure 5. Concordia diagrams of LA-ICP-MS zircon U-Pb data from granite samples from the porphyry-skarn W-Mo deposits in the Yunkai area.

In Sample GT02, zircon grains are mostly colorless, transparent or translucent, and a part is light brown. The grain size ranges in 50–300 μm, and the length to width ratios are between 1: 1 and 4: 1. In the cathodoluminescence (CL) images (Fig. 4, GT02), almost all the zircons show typical rhythmic oscillation zoning, indicating magmatic origin. Sixteen zircon grains yielded a weighted mean 206Pb/238U age of 98±1 Ma (MSWD=0.5) (Table 1, Fig. 5, GT02).

4.1.2 Youmapo biotite granite

In Sample SY03, the Youmapo biotite granite, zircon grains are mostly colorless, transparent or translucent, and a part is brown. The size ranges in 50–250 μm, and the length to width ratios are between 1: 1 and 3: 1. In the cathodoluminescence (CL) images (Fig. 4, SY03), almost all the zircons show typical rhythmic oscillation zoning, indicating magmatic origin. Seventeen zircon grains yielded a weighted mean 206Pb/238U age of 105±1 Ma (MSWD=1.9) (Table 1, Fig. 5, SY03).

4.1.3 Sanchachong biotite granite

In Sample SC07, the Sanchachong biotite granite, zircon grains are mostly colorless, transparent or translucent. The grain size ranges in 30–300 μm, and the length to width ratios are between 1: 1 and 4: 1. In the cathodoluminescence (CL) images (Fig. 4, SC07), almost all the zircons show typical rhythmic oscillation zoning, indicating magmatic origin. Fifteen zircon grains yielded a weighted mean 206Pb/238U age of 103±1 Ma (MSWD= 0.98) (Table 1, Fig. 5, SC07). Two analyses point to inherited zircons, showing 206Pb/238U ages of 197±9 and 1 218±72 Ma.

4.1.4 Songwang granite

In Sample SW08 of the Songwang granite, zircon grains are mostly colorless, transparent or translucent. The grain size ranges in 40–300 μm, and the length to width ratios are between 1: 1 and 5: 1. In the cathodoluminescence (CL) images (Fig. 4, SW08), almost all the zircons show typical rhythmic oscillation zoning, indicating magmatic origin.

Twenty zircon grains yielded a weighted mean 206Pb/238U age of 88±1 Ma (MSWD=1.4) (Table 1, Fig. 5, SW08). Three analyses also point to inherited zircons, showing 206Pb/238U ages of 286±4, 292±4 and 2 628±54 Ma.

4.2 Hf Isotopic Compositions

On the basis of the U-Pb age, we choose five samples for the zircon Hf isotopic analyses. The results are listed in Table 2. Fourteen magmatic zircons from the mafic enclaves of Sample MC10 show significantly higher 176Hf/177Hf ratio than those zircons from the biotite granite (Sample MC02), with εHf(t) values range from 1.3 to 10.1 when calculated at t=109 Ma, and the corresponding two-stage depleted mantle Hf model ages (TDM2) range from 521 to 1 085 Ma (Figs. 6a, 6b).

Table 2 Hafnium isotope analyses of zircons of the Late Yanshanian granites from the porphyry-skarn W-Mo deposits in the Yunkai area
Download:
Figure 6. Zircon εHf(t) values and two-stage Hf model ages (TDM2) for granite samples from the porphyry-skarn W-Mo deposits in the Yunkai area.

Sixteen magmatic zircons from Sample GT02 granite samples show a relatively uniform range of εHf(t) values from -5.9 to -3.1 when calculated at t=105 Ma, and the corresponding two-stage depleted mantle Hf model age (TDM2) ranges from 1 355 to 1 534 Ma (Figs. 6c, 6d).

Sixteen magmatic zircons from Sample SY03 granite samples show a relatively uniform range of εHf(t) values from -2.5 to -0.6 when calculated at t=105 Ma, the corresponding two-stage depleted mantle Hf model age (TDM2) ranges from 521 to 1 085 Ma (Figs. 6e, 6f).

Thirteen magmatic zircons from Sample SC07 show a small εHf(t) range from -5.2 to -2.0 when calculated at t=103 Ma, and the corresponding two-stage depleted mantle Hf model age (TDM2) ranges from 1 334 to 1 494 Ma. Two detrital zircon cores (197 and 1 218 Ma) show εHf(t) values of -1.3 and 6.2, and the calculated TDM2 ages are 1 314 and 1 628 Ma (Figs. 6g, 6h)).

Fourteen magmatic zircons from Sample SW08 show εHf(t) values of -5.2 to -3.6 when calculated at t=88 Ma, and the corresponding two-stage depleted mantle Hf model ages (TDM2) range from 1 381 to 1 482 Ma (Figs. 6i, 6j). One detrital zircon core (2 628 Ma) shows an εHf(t) value of 6.4, and the calculated TDM2 age is 2 708 Ma.

4.3 Sulfur Isotopic Compositions

The sulfur isotope results of the sulfides in the Yunkai area are listed in Table 3. As is shown in Table 3 and Fig. 7, the value of δ34S is between -0.3‰ and 5.2‰ for pyrite, the average value is 2.2‰ (n=11). One pyrrhotite sample shows a δ34S value of 2.4‰. Galena shows δ34S value between -4.2‰ and 1.0‰, and the average value is 0.9‰ (n=7). Sphalerite shows δ34S value of 2.9‰ to 3.2‰, and the average value is 3.0‰ (n=7). Overall, the distribution of the δ34S values in the deposits is very concentrated near zero, indicating that the sulfur was likely from a single magmatic source.

Table 3 Sulfur isotopic compositions from porphyry-skarn W-Mo deposits in the Yunkai area
4.4 Fe Isotopic Compositions

The results of Fe isotopic compositions of pyrite are shown in Fig. 8 and Table 4, which show a δ56Fe value from 0.16‰ to 0.58‰, with an average of 0.35‰. The δ57Fe values are from 0.02‰ to 0.54‰, with an average of 0.48‰. The results show that there is no significant Fe isotopic fractionation of pyrite in different ore deposits in the Yunkai area, and value is falling in a narrow range near zero.

Table 4 Fe isotopic compositions from porphyry-skarn W-Mo deposits in the Yunkai area
5 DISCUSSION 5.1 Ages for Late Yanshanian Magmatism

Accoding to the results of LA-ICP-MS zircon U-Pb dating of granites in the Yunkai area, three stages of granitic magmatism can be distinguished: 113–110, 105–98 and 88 Ma, and all of them belong to Late Yanshanian. Together with regional tectono-magmatic evolution at the Late Mesozoic, the same periods of magmatism widely exist in South China.

Previous biotite K-Ar dating suggests the Michang granite was emplaced at 120 Ma, but our new precise LA-ICP-MS zircon U-Pb dating indicates an age of 113±1 or 110±1 Ma for the emplacement of this granite. In addition, the Youmapo biotite granite was also emplaced at 110±1 Ma. In South China, there is a wide occurrence of ~110 Ma magmatic rocks. For example, the Quanzhou gabbro and adamellite from the coastal Fujian Province show emplacement ages of 111±1, 109±1 and 108±1 Ma (Li Z et al., 2012). The Pingtan hornblende gabbros from southeast Fujian have an age of 115.2±1.2 Ma (Dong et al., 1997). The Putuo quartz monzodiorite in the coastal Zhejiang Province shows an age of 110.2±1.1 Ma (Qiu et al., 1999). The Ru'ao diabase and granite from the eastern Zhejiang Province show ages of 109.1±2.8 (whole rock Ar-Ar) and 116±3 Ma (SHRIMP zircon U-Pb), respectively (Dong et al., 2007).

The Longwangtang granite from Southeast Zhejiang Province shows an age of 109.8±0.4 Ma (Chen et al., 1991). In addition, Xu et al. (1999) reported a Sm-Nd isochron age of 112.3±17.8 Ma for a gabbroic granulite xenolith from the Qilin Cenozoic basaltic breccia pipe from Guangdong Province, suggesting an underplating of basaltic magma during this period at China's continental margin. The granites from the Michang, Sanchachong, Songwang and Youmapo deposits all show emplacement ages of 103±1, 105±1, 98±1 and 103±1 Ma, respectively.

Previous geochronology studies have shown that a set of I-type granite of highly calc-alkaline may exist in the southeast coastal areas during the late Early Cretaceous Period, such as the Fuzhou pluton (104±5 Ma) and Danyang pluton (103±10 Ma) from Fujian Province (Martin et al., 1994), the Nongliang pluton (101.2±0.3 Ma) from Zhejiang Province (Chen et al., 1991). Recent studies suggest that the late Early Cretaceous Period is one of the most important tectono-magmatic events in Southeast China, and a large number of mafic to felsic magmatic rocks developed in this period, such as the Guangxi Longtuoshan rhyolitic porphyry (100.3±1.4 Ma) and granite porphyry (100.3±1.4 Ma) (Chen et al., 2008), the Dachang Longxianggai granite (103–102 Ma) (Liang et al., 2011), the mafic dykes (110–100 Ma) from the Northwest Jiangxi Province (Xie et al., 2002), thevolcanic-intrusive rocks (99–104 Ma) from the western Guangdong Province (Geng et al., 2006), the mafic dykes (103–110 Ma) from the Northern Guangdong Province (Li et al., 1997), the granites (103±1 Ma) from the Southeast Zhejiang Province (Li Y J et al., 2009), the Qingtian alkaline A-type granite (101.2±2.1 Ma) and the Yandangshan volcanic rocks (97.2–105.6 Ma) from Zhejiang Province (Yu et al., 2006; Qiu et al., 1999), and the felsic volcanic rocks (104–95 Ma) in eastern Guangdong and Fujian provinces (Guo et al., 2012). In addition, there are also reports for 101 Ma mafic dyke swarm in China's southernmost Hainan Island (Tang et al., 2010).

Geochronology data show that the Late Cretaceous (~90 Ma) is also an important tectono-magmatic activity period in Southeast China (Fig. 9). The Songwang granite was formed during this stage (88±1 Ma). The magmatic rocks emplaced during this period include: the Sheshan granite (91.1±0.3 Ma) and Dachang intermediate-felsic intrusive rocks (93–91 Ma) in Guangxi Province (Chen et al., 2011; Cai et al., 2006); the mafic dykes (91–88 Ma) in northern Guangdong Province (Li et al., 1997); the basalts and the mafic dikes (93–90 Ma) near the Chenzhou-Ningwu fault zone in Hunan Province (Wang and Shen, 2003); the alkaline granite in Taohuadao, Yaokeng and Daheshan, and the miarolite granite in the Putuoshan (94–86 Ma) in the Zhejiang Province (Xiao et al., 2007; Wang et al., 2005; Qiu et al., 1999), the alkaline granite and high-differentiation I-type granites (96–92 Ma) in Fujian Province (Qiu et al., 2008; Martin et al., 1994), and the Fork River and Sanya mafic dike swarm (~93 Ma) from Hainan Island (Tang et al., 2010). In addition, SHRIMP zircon U-Pb dating of metamorphosed granite in Taiwan shows that the granite rock was originally formed in 88–87 Ma (Yui et al., 2009).

Download:
Figure 9. Histograms and cumulative probability plots of isotopic ages for Yanshanian igneous rocks in SE China (after Li et al., 2010).

After compilation of all the available magmatic ages in Late Mesozoic (Jurassic and Cretaceous) in Southeast China, we found two significant peaks: ~100 and ~90 Ma (Fig. 9). This age distribution may suggest that there occurred two stages of strong magmatism in Southeast China during Late Yanshanian. In this paper, the granites of Michang, Youmapo, Sanchachong, and Songwang show ages of 103 and 88 Ma, corresponding to the two age peaks, indicating that the magmatic activity in the Yunkai area at Cretaceous belongs to parts of the tectono-magmatic evolution at the whole Southeast China.

5.2 Magma Source of the Late Yanshanian Granites in the Yunkai Area

Zircon Hf model ages (TDM2) for the Michang biotite granite are centered on 1.3–1.2 Ga (except for one analysis), whereas the ages for the Sanchachong biotite granite and Songwang granite are slightly older at 1.5–1.3 Ga. The Michang biotite granite contains mafic enclaves, but the rest of granites (Sanchachong, Songwang and Guandi) have no such mafic enclaves but may contain xenoliths of the country rocks. Zircons from the mafic enclaves show higher εHf(t) > 0, whereas those zircons from the granites show lower εHf(t) < 0, and there is tendency of εHf(t) decrease from the Michang (110±1 Ma) to Sanchachong (103±1 Ma) and Songwang (88±1 Ma) granites (Fig. 10).

Download:
Figure 10. Relation of zircon εHf(t) values versus U-Pb ages for granite samples from the porphyry-skarn W-Mo deposits in the Yunkai area.

Therefore, we suggest that the Sanchachong biotite granite and Songwang granite were derived mainly from Middle Proterozoic crustal materials, whereas the Michang biotite granite may have a mantle component during magma generation.

An important question is whether there is any juvenile Proterozoic crust overgrowth at Yunkai area. Qin et al. (2006) reported a SHRIMP zircon U-Pb age of 1 462±28 Ma for the plagioclase amphibolite from the Yunkai Group in Southeast Guangxi Province, which is interpreted as metamorphosed OIB-type mafic volcanic rocks, suggesting the existence of juvenile Proterozoic mafic crust in Yunkai area. Gilder et al. (1996) reported Nd model ages of 1.4±0.3 Ga for 23 Mesozoic granites in South China, and they also suggested occurrence of a wide range of Proterozoic crust in South China. Wang and Shen (2003) used the Nd model ages of granites in the Southeast China as well as the U-Pb ages of inherited zircons in the crustal rocks to suggest an episodic crustal growth characteristic in Southeast China, and the Middle Proterozoic (~1.4 Ga) is one of the most important stages for the crustal growth. It is also important to note that a number of 1.3–1.4 Ga detrital zircon with positive εHf(t) values and younger TDM2 are found from the Neoproterozoic sedimentary rocks in the Southern Yangtze Block and the Cathysia Block (including the Wuyi Mountain, Nanling, Yunkai areas), which also indicates existence of Middle Proterozoic crust in South China (Liu et al., 2010; Wang D H et al., 2010; Yu et al., 2010, 2008). All the above evidence indicates the existence of the juvenile Middle Proterozoic crusts in South China including the Yunkai area, therefore it is suggested that these crustal materials may provide an important source for the magmatic rocks of Late Yanshanian in this region.

The existence of mafic enclaves in the Michang biotite granite indicates contribution of mantle-derived magma and its interaction with crustal derived felsic magma, which is also supported by the zircon Hf isotope data which show a relatively higher εHf(t) values and young two-stage model Hf TDM2 age for the Michang biotite granite and its mafic enclaves than the other granites in the district (Fig. 10). In addition, there also exists one positive εHf(t) value (1.4) for zircon from the biotite granite, which is similar to the εHf(t) values (1.3–10.1) for the mafic enclaves, indicating an magma mixing process for the generation of the granitic magma. The mantle-derived magma can also provide deep heat for the middle and lower crust material to partial melting to generate granite magma.

5.3 Source of the Ore-Forming Materials in the Yunkai Area

Sulfides from the ore deposits show a small δ34S variation around zero, which may indicate that the sulfur source was derived from the single magmatic fluid. Together with sulfur isotope data from previous studies (e.g., Fu et al., 2014), all the ores of skarn-type and quartz vein-type show consistent sulfur isotopic composition with a narrow range close to zero. This δ34S range indicates that the sulfur of all these skarn- and vein-type deposits was derived from a single source related to magmatic hydrothermal fluid with the H2S as the dominant species (Ohmoto and Rye, 1979; Ohmoto, 1972). The sulfide minerals are mainly pyrite, chalcopyrite and molybdenite, without sulfate minerals. To trace the sulfur source, we need to apply the total sulfur isotopic composition (δ34SΣ) of the hydrothermal fluids during sulfide precipitation. When H2S predominates in the fluid system, under the condition of equilibrium, δ34SΣ≈δ34Sfluid≈δ34Spyrite, as a result, the near zero δ34S value indicates that the sulfur source is single in the main metallogenic precipitation period, possibly from deep-sourced magma. Therefore, the mineralization in the Youmapo tungsten-molybdenum deposit, Sanchachong tungsten deposit and Songwang tungsten-tin deposit has a close relationship with the Late Yanshanian magmatism.

Iron isotope system is a newly developed non-traditional isotope system that has already been applied in solving a variety of geologic problems including ore genesis. As iron is one of the major metallogenic elements, iron isotopic geochemistry can provide a new tracer for the mineralization, which has shown its important role in tracing the source of ore-forming materials and fluids, the fluid evolution, the supergene alteration and other important mineralization processes, such as the BIF (Dauphas et al., 2004; Johnson et al., 2003), Precambrian stratiform sulfide deposits (Zhu et al., 2008), the Archean komatiite-hosted Ni deposits (Bekker et al., 2009), the Archaean quartz-conglomerate- type gold deposits (Hofmann et al., 2009), the modern ocean floor hydrothermal systems (Sharma, 2001), and the porphyry and skarn-type deposits (Wang Y et al., 2011; Graham et al., 2004). All these studies indicate that the iron isotope has a great potential in tracing the ore-forming mechanism.

The three typical porphyry and skarn-type deposits of Sanchachong, Youmapo and Songwang show identical Fe isotopic compositions of pyrite near zero. This Fe isotope characteristic may suggest the source of iron in the deposits may be derived from magma, which is in support from the sulfur isotope data as we discussed above. Therefore, the mineralization is closely related to magmatism.

5.4 Late Yanshanian W-Mo Mineralization Event

The mineralization age for the porphyry and skarn-type deposit is generally close to the age of related granites, therefore we can date the ore-related magmatic rocks to indirectly constrain the metallogenic epoch. For example, the Cu-Au-Mo-related granodioritic porphyries from the porphyry and skarn-type ore deposits at Jiurui District, Jiangxi Province show zircon U-Pb ages between 138.2±1.8 and 148.0±1.0 Ma (Jiang et al., 2013; Xu et al., 2013, 2012; Yang et al., 2011; Li and Jiang, 2009; Ding et al., 2005), which are identical to the molybdenite Re-Os ages of 137.9±1.0 and 146.4±2.6 Ma (Li et al., 2007; Wu and Zou, 1997). In the Dexing porphyry-type Cu deposit, Zhou et al. (2012) obtained molybdenite Re-Os ages of 170.4±1.8 to 172.3±2.3 Ma, which are also similar to the ages (170.2±0.9 to 172.5±0.5 Ma) of ore-bearing porphyry (Liu et al., 2012). Taking all the zircon U-Pb age data in the Yunkai area in Guangxi Province, the Michang, Sanchachong and Songwang granites show ages of 113, 103 and 88 Ma, therefore it is reasonable to estimate that the Michang skarn-type tungsten-molybdenum deposit, the Sanchachong skarn-type tungsten-molybdenum deposit and the Songwang porphyry molybdenum-tungsten deposit were all formed during the Late Cretaceous (80–110 Ma).

In South China, multiple stages of tectonic-magmatic events produced polycyclic magmatic rocks and assoicated Cu-Au-Pb-Zn-Ag and W-Sn-Mo mineralizations (Li and Jiang, 2016; Li et al., 2016; Xu et al., 2015; Jiang et al., 2013, 2008, 2006; Guo et al., 2012; Mao et al., 2011, 2008; Wang and Shen, 2003). Most of the granites were emplaced in a cyclic manner during the Caledonian, Indosinian and Yanshanian periods (Hua et al., 2013). The Yunkai area is a typical area in South China where developed typical Caledonian movement, which produced large Caledonian granites, and lots of the mineralization in this district have a close genetic relation with the Caledonian granites. For example, Chen et al. (2011) reported Caledonian ages for the Sheshan biotite granodiorite and the Shedong tungsten-molybdenum deposit (437.8 Ma). Li X et al. (2012) reported zircon SHRIMP U-Pb age of 429.6±4.3 Ma for the biotite granite and scheelite Sm-Nd isochron age of 431±12 Ma for the Niutangjie skarn-type tungsten deposit. In recent years, a number of Indosinian W-Sn-Mo deposits have been found in the Yunkai area and its adjacent regions, such as the Li Guifu tungsten- tin deposit (213.3±2.9 Ma, Zhou et al., 2009) and the Yuntoujie W-Mo deposit (213.3±2.9 Ma, Wu et al., 2012).

It is worth attention that in the Yunkai area, the Michang tungsten-molybdenum deposit, the Sanchachong tungsten- molybdenum deposit, the Youmapo tungsten-molybdenum deposit and the Songwang molybdenum-tungsten deposit were all formed during Late Yanshanian stage of magmatism and mineralization (Late Cretaceous). Combined all available data, it is clear that the Yunkai area which is located in the southwest side of the Qinhang metallogenic belt developed the Late Cretaceous magmatic rocks (80–100 Ma) and related tungsten- molybdenum-copper (gold) deposits (Table 5). Li et al. (2008) obtained a molybdenite Re-Os isochron age of 95.4±1.0 Ma for the Damingshan tungsten deposit in Guangxi Province and molybdenite Re-Os model ages of 95.0–95.8 Ma for the Maling tungsten deposit, which is similar to the white mica 39Ar/40Ar ages (97.1±0.8, 98.0±1.0 Ma). In the Guangxi Longtoushan gold deposits, the ore-bearing granitic porphyry has emplacement ages of 96.1±3 to 100.3±1.4 Ma (Duan et al., 2011; Chen et al., 2008), which are similar to the Pingtianshan intrusive rocks (96.2±0.4 Ma) in the area. In the Dayaoshan area, the granite porphyry related to the Baoshan porphyry copper deposit shows an emplacement age of 91.1±0.6 Ma (Bi et al., 2015). All these data suggest existence of a wide range of Late Yanshanian magmatism and mineralization in the Yunkai area.

Table 5 Representative geochronology ages of Late Cretaceous magmatic rocks (80–100 Ma) and related W-Mo-(Sn-Cu) mineralization in South China

Late Yanshanian W-Sn and Cu-Au polymetallic mineralizations are widely distributed in the southeast coast, Southwest Yunnan and Guangxi provinces and other regions in South China. Among them, the metallogenic epoch of the W-Sn deposits in West Yunnan and Guangxi provinces are mostly concentrated in Late Cretaceous, in agreement with the magmatic emplacement ages. For example, Wang et al. (2005) reported fluid inclusions 39Ar/40Ar ages of 91.4±2.9, 94.5±0.3 and 94.6±0.5 Ma for the Dachang tin-polymetallic deposit in Guangxi Province. Cheng et al. (2013) reported sericite and phlogopite 39Ar/40Ar ages of 77.4±0.6 to 95.3±0.7 Ma for the Yunnan Gejiu Sn-W deposits in Yunnan Province, which are similar to the molybdenite Re-Os age (83.4±2.1 Ma) in the Kafang deposit. In the southeast coastal region, a number of hypabyssal type low temperature hydrothermal copper-gold-silver deposits also formed at around 100 Ma (Mao et al., 2008).

Therefore, it is suggested that magmatism and mineralization are widely developed in this area during Late Cretaceous Period, and the magmatic rocks and W-Mo-Cu-Au deposits occur not only in continental margin coastal areas in South China, but also in the inland regions such as the Yunkai area, which has significant implications in finding Late Yanshanian mineralization and those closely related magmatism in the Yunkai area.

6 CONCLUSIONS

(1) A wide range of magmatism and mineralization in the Yunkai area of South China occur during the Late Yanshanian Period.

(2) Zircon U-Pb ages of the ore-bearing biotite granites and their mafic enclaves from the newly discovered Michang, Youmapo, Sanchachong and Songwang porphyry-skarn W-Mo deposits are from 88±1 to 110±1 Ma.

(3) Hf isotopic compositions of granitic zircons show negative εHf(t) values of -5.9 to -0.6, with calculated Hf model age (TDM2) of 1.5–1.2 Ga, indicating that the Middle Proterozoic crustal materials may have provided an important source for the magmatic rocks in this district during the Late Yanshanian Period.

(4) Sulfur and iron isotopes of the sulfides from the porphyry-skarn type W-Sn-Mo deposits in the Yunkai area indicate that the ore-forming materials may come from the deep- sourced granitic magma, and the mineralizations show a close relationship with the granitic magmatism during the Late Yanshanian Period.

ACKNOWLEDGMENTS

This work was supported by the Fundamental Research Funds for the Central Universities (No. CUG120702). The final publication is available at Springer via https://doi.org/10.1007/s12583-017-0901-1.


REFERENCES CITED
Bekker, A., Barley, M. E., Fiorentini, M. L., et al., 2009. Atmospheric Sulfur in Archean Komatiite-Hosted Nickel Deposits. Science, 326(5956): 1086-1089. DOI:10.1126/science.1177742
Bi, S. J., Yang, Z., Li, W., et al., 2015. Discovery of Late Cretaceous Baoshan Porphyry Copper Deposit in Dayaoshan, Qinhang Metallogenic Belt:Constraints from Zircon U-Pb Age and Hf Isotope. Earth Sci-ence-Journal of China University of Geosciences, 40(9): 1458-1479. DOI:10.3799/dqkx.2015.132
Blichert-Toft, J., Chauvel, C., Albarède, F., 1997. Separation of Hf and Lu for High-Precision Isotope Analysis of Rock Samples by Magnetic Sector-Multiple Collector ICP-MS. Contributions to Mineralogy and Petrology, 127(3): 248-260. DOI:10.1007/s004100050278
Cai, M. H., He, L. Q., Liu, G. Q., et al., 2006. SHRIMP Zircon U-Pb Dating of the Intrusive Rocks in the Dachang Tin-Polymetallic Ore Field, Guangxi and Their Geological Significance. Geological Review, 52(3): 409-414.
Chen, C. H., Liu, Y. H., Lee, C. Y., et al., 2012. Geochronology of Granulite, Charnockite and Gneiss in the Poly-Metamorphosed Gaozhou Complex (Yunkai Massif), South China:Emphasis on the In-Situ EMP Monazite Dating. Lithos, 144-145: 109-129. DOI:10.1016/j.lithos.2012.04.009
Chen, F. W., Li, H. Q., Mei, Y. P., 2008. Zircon SHRIMP U-Pb Chronology of Mineralization of the Longtoushan Porphyry Gold Orefield, Gui County, Guangxi. Acta Geologica Sinica, 82(7): 921-926.
Chen, J. F., Zhou, T. X., Yin, C. S., 1991. 40Ar-39Ar Dating of Several Mesozoic Plutons in Southeastern Zhejiang Province. Acta Petrologica Sinica, 7(3): 37-44.
Chen, M. H., Mo, C. S., Huang, Z. Z., et al., 2011. Zircon LA-ICP-MS U-Pb Ages of Granitoid Rocks and Molybdenite Re-Os Age of Shedong W-Mo Deposit in Cangwu County of Guangxi and Its Geological Dignificance. Mineral Deposits, 30(6): 963-978.
Chen, Y. C., Pei, R. F., Zhang, H. L., 1990. The Geology of Nonferrous and Rare Metal Deposits Related to Mesozoic Granitoids in the Nanling Region, China. Acta Geoscientica Sinica, 20(1): 79-85.
Cheng, Y. B., Mao, J. W., Chang, Z. S., et al., 2013. The Origin of the World Class Tin-Polymetallic Deposits in the Gejiu District, SW China:Constraints from Metal Zoning Characteristics and 40Ar-39Ar Geochronology. Ore Geology Reviews, 53(2): 50-62. DOI:10.1016/j.oregeorev.2012.12.008
Dauphas, N., Van, Z, M., Wadhwa, M., et al., 2004. Clues from Fe Isotope Variations on the Origin of Early Archean BIFs from Greenland. Science, 306(5704): 2077-2080. DOI:10.1126/science.1104639
Deng, X. G., Chen, Z. G., Li, X. H., et al., 2004. SHRIMP U-Pb Zircon Dating of the Darongshan-Shiwandashan Granitoid Belt in Southeastern Guangxi, China. Geological Review, 50(4): 426-432.
Ding, X., Jiang, S. Y., Zhao, K. D., et al., 2005. In-Situ U-Pb SIMS Dating and Trace Element (EMPA) Composition of Zircon from a Granodiorite Porphyry in the Wushan Copper Deposit, China. Mineralogy and Petrology, 86(1/2): 29-44. DOI:10.1007/s00710-005-0093-5
Dong, C. W., Xu, X. S., Yan, Q., et al., 2007. A New Case of Late Mesozoic Crust-Mantle Interaction in Eastern Zhejiang:Geochronology and Geo-chemistry of the Ru'ao Diabase-Granite Composite Intrusions. Acta Petrologica Sinica, 23(6): 1303-1312.
Dong, C. W., Zhou, X. M., Li, H. M., et al., 1997. Late Mesozoic Crust-Mantle Interaction in Southeastern Fujian. Chinese Science Bulletin, 42(6): 495-498. DOI:10.1007/bf02882602
Duan, R. C., Ling, W. L., Li, Q., et al., 2011. Correlations of the Late Yanshanian Tectonomagmatic Events with Metallogenesis in South China:Geochemical Constraints from the Longtoushan Gold Ore De-posit of the Dayaoshan Area, Guangxi Province. Acta Geologica Sinica, 85(10): 1644-1658.
Fu, Q., Ge, W. S., Wen, C. S., et al., 2011. Geochemistry and Genesis of Michang Granites and Their Dark Microgranular Enclaves in Guangxi. Acta Geoscientica Sinica, 32(3): 293-303.
Fu, Q., Ge, W. S., Wen, C. S., et al., 2014. Geochemistry and Genesis of Youmapo W-Mo Deposit in Guangxi. Mineral Deposits, 33(4): 785-794.
Geng, H. Y., Xu, X. S., O'Reilly, S. Y., et al., 2006. Cretaceous Volcanic-Intrusive Magmatism in Western Guangdong and Its Geological Sig-nificance. Science in China Series D:Earth Sciences, 49(7): 696-713. DOI:10.1007/s11430-006-0696-7
GGST (Guangxi Geology Survey Team), 1986. Reports on 1:50 000 Regional Geological Surveys of Yulin, Longsheng, Shatian, Michang. Report of Guangxi Geology Survey Team, Nanning.
Gilder, S. A., Gill, J., Coe, R. S., et al., 1996. Isotopic and Paleomagnetic Constraints on the Mesozoic Tectonic Evolution of South China. Journal of Geophysical Research:Solid Earth, 101(B7): 16137-16154. DOI:10.1029/96jb00662
Graham, S., Pearson, N., Jackson, S., et al., 2004. Tracing Cu and Fe from Source to Porphyry:In Situ Determination of Cu and Fe Isotope Ratios in Sulfides from the Grasberg Cu-Au Deposit. Chemical Geology, 207(3/4): 147-169. DOI:10.1016/j.chemgeo.2004.02.009
Griffin, W. L., Pearson, N. J., Belousova, E., et al., 2000. The Hf Isotope Composition of Cratonic Mantle:LAM-MC-ICPMS Analysis of Zircon Megacrysts in Kimberlites. Geochimica et Cosmochimica Acta, 64(1): 133-147. DOI:10.1016/S0016-7037(99)00343-9
Griffin, W. L., Wang, X., Jackson, S. E., et al., 2002. Zircon Chemistry and Magma Mixing, SE China:In Situ Analysis of Hf Isotopes, Tonglu and Pingtan Igneous Complexes. Lithos, 61(3-4): 237-269. DOI:10.1016/S0024-4937(02)00082-8
Guo, F., Fan, W. M., Li, C. W., et al., 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(7): 62-84. DOI:10.1016/j.lithos.2011.12.009
Hofmann, A., Bekker, A., Rouxel, O., et al., 2009. Multiple Sulphur and Iron Isotope Composition of Detrital Pyrite in Archaean Sedimentary Rocks:A New Tool for Provenance Analysis. Earth and Planetary Science Letters, 286(3/4): 436-445. DOI:10.1016/j.epsl.2009.07.008
Hu, Z. C., Gao, S., Liu, Y. S., et al., 2008a. Signal Enhancement in Laser Ablation ICP-MS by Addition of Nitrogen in the Central Channel Gas. Journal of Analytical Atomic Spectrometry, 23(8): 1093-1101. DOI:10.1039/b804760j
Hu, Z. C., Liu, Y. S., Gao, S., et al., 2008b. A Local Aerosol Extraction Strategy for the Determination of the Aerosol Composition in Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Journal of Analytical Atomic Spectrometry, 23(9): 1192-1203. DOI:10.1039/b803934h
Hu, Z. C., Liu, Y. S., Gao, S., et al., 2012a. Improved In Situ Hf Isotope Ratio Analysis of Zircon Using Newly Designed X Skimmer Cone and Jet Sample Cone in Combination with the Addition of Nitrogen by Laser Ablation Multiple Collector ICP-MS. Journal of Analytical Atomic Spectrometry, 27(9): 1391-1399. DOI:10.1039/C2JA30078H
Hu, Z. C., Liu, Y. S., Gao, S., et al., 2012b. A "Wire" Signal Smoothing Device for Laser Ablation Inductively Coupled Plasma Mass Spec-trometry Analysis. Spectrochimica Acta Part B Atomic Spectroscopy, 78: 50-57. DOI:10.1016/j.sab.2012.09.007
Hua, R. M., Zhang, W. L., Chen, P. R., et al., 2013. Relationship between Caledonian Granitoids and Large-Scale Mineralization in South China. Geological Journal of China Universities, 19(1): 1-11.
Jiang, S. Y., Xu, R. M., Zhu, Z. Y., et al., 2013. Study on Mesozoic Tectonics and Granitic Magmatism and Their Relationship with Cu-Au Min-eralization in the Jiurui Ore District, Jiangxi Province. Acta Petrologica Sinica, 29(12): 4051-4068.
Jiang, S. Y., Zhao, K. D., Jiang, Y. H., et al., 2006. A New Type of Tin Mineralization Related to Granite in South China:Evidence from Mineral Chemistry, Element and Isotope Geochemistry. Acta Petrologica Sinica, 22(10): 2509-2516.
Jiang, S. Y., Zhao, K. D., Jiang, Y. H., et al., 2008. Characteristics and Genesis of Mesozoic A-Type Granites and Associated Mineral Deposits in the Southern Hunan and Northern Guangxi Provinces along the Shi-Hang Belt, South China. Geological Journal of China Universities, 14: 283-294.
Johnson, C. M., Beard, B. L., Beukes, N. J., et al., 2003. Ancient Geochemical Cycling in the Earth as Inferred from Fe Isotope Studies of Banded Iron Formations from the Transvaal Craton. Contributions to Mineralogy & Petrology, 144(5): 523-547. DOI:10.1007/s00410-002-0418-x
Li, B., Jiang, S. Y., Zhang, Q., et al., 2016. 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, 35: 217-237. DOI:10.1016/j.gr.2015.05.006
Li, J. W., Li, X. H., Pei, R. F., et al., 2007. Re-Os Age of Molybdenite from the Southern Ore Zone of the Wushan Copper Deposit, Jiangxi Province, and Its Geological Significance. Acta Geologica Sinica, 81(6): 801-807.
Li, L., Jiang, S. Y., 2009. Petrogenesis and Geochemistry of the Dengjiashan Porphyritic Granodiorite, Jiujiang-Ruichang Metallogenic District of the Middle-Lower Reaches of the Yangtze River. Acta Petrologica Sinica, 25: 2877-2888.
Li, Q., Duan, R. C., Ling, W. L., et al., 2009. Detrital Zircon U-Pb Geo-chronology of the Early Paleozoic Strata in Eastern Guangxi and Its Constraint on the Caledonian Tectonic Nature of the Cathaysian Con-tinental Block. Earth Science—Journal of China University of Geo-sciences, 34(1): 189-202. DOI:10.3799/dqkx.2009.017
Li, Q., Jiang, S. Y., 2016. Trace and Rare Earth Element Characteristics in Fe-Mn Carbonates Associated with Stratiform Ag-Pb-Zn Mineralization from the Lengshuikeng Ore District, Jiangxi Province:Implications for Their Genesis and Depositional Environment. Journal of Earth Science, 27(4): 571-583. DOI:10.1007/s12583-016-0908-9
Li, S. R., Wang, D. H., Liang, T., et al., 2008. Metallogenic Epochs of the Damingshan Tungsten Deposit in Guangxi and Its Prospecting Potential. Acta Geologica Sinica, 82(7): 873-879.
Li, X., Feng, Z., Xiao, R., et al., 2012. Spatial and Temporal Distributions and the Geological Setting of the W-Sn Mo-Nb-Ta Deposits at the Northeast Guangxi, South China. Acta Geologica Sinica, 86(11): 1713-1725.
Li, X. H., Hu, R. Z., Rao, B., 1997. Geochronology and Geochemistry of Cretaceous Mafic Dikes from Northern Guangdong, SE China. Geo-chimica, 26(2): 14-31.
Li, X. H., Li, W. X., Wang, X. C., et al., 2010. SIMS U-Pb Zircon Geochronology of Porphyry Cu-Au-(Mo) Deposits in the Yangtze River Metallogenic Belt, Eastern China:Magmatic Response to Early Cretaceous Lithospheric Extension. Lithos, 119(3/4): 427-438. DOI:10.1016/j.lithos.2010.07.018
Li, Y. J., Wei, J. H., Yao, C. L., et al., 2009. Zircon U-Pb Dating and Tectonic Significance of the Shipingchuan Granite in Southeastern Zhejiang Province, SE China. Geological Review, 55(5): 673-684.
Li, Z., Qiu, J. S., Xu, X. S., 2012. Geochronological, Geochemical and Sr-Nd-Hf Isotopic Constraints on Petrogenesis of Late Mesozoic Gabbro-granite Complexes on the Southeast Coast of Fujian, South China:Insights into a Depleted Mantle Source Region and Crust-Mantle Interactions. Geological Magazine, 149(3): 459-482. DOI:10.1017/s0016756811000793
Li, Z. X., Li, X. H., 2007. Formation of the 1 300-km-Wide Intracontinental Orogen and Postorogenic Magmatic Province in Mesozoic South China:A Flat-Slab Subduction Model. Geology, 35(2): 179. DOI:10.1130/g23193a.1
Li, Z. X., Li, X. H., Wartho, J. A., et al., 2009. Magmatic and Metamorphic Events during the Early Paleozoic Wuyi-Yunkai Orogeny, Southeastern South China:New Age Constraints and Pressure-Temperature Condi-tions. Geological Society of America Bulletin, 122(5/6): 772-793. DOI:10.1130/b30021.1
Liang, T., Wang, D. H., Hou, K. J., et al., 2011. LA-MC-ICP-MS Zircon U-Pb Dating of Longxianggai Pluton in Dachang of Guangxi and Its Geological Significance. Acta Petrologica Sinica, 27(6): 1624-1636.
Ling, H. F., Shen, W. Z., Sun, T., et al., 2006. Genesis and Source Charac-teristics of 22 Yanshanian Granites in Guangdong Province:Study of Element and Nd-Sr Isotopes. Acta Petrologica Sinica, 22(11): 2687-2703.
Liu, R., Zhou, H. W., Zhang, L., et al., 2010. Zircon U-Pb Ages and Hf Isotope Compositions of the Mayuan Migmatite Complex, NW Fujian Province, Southeast China:Constraints on the Timing and Nature of a Regional Tectonothermal Event Associated with the Caledonian Orogeny. Lithos, 119(3/4): 163-180. DOI:10.1016/j.lithos.2010.06.004
Liu, S., Wang, D., Chen, Y., et al., 2008. 40Ar/39Ar Ages of Muscovite from Different Types Tungsten-Bearing Quartz Veins in the Chong-Yu-You Concentrated Mineral Area in Gannan Region and Its Geological Significance. Acta Geologica Sinica, 82(7): 932-940.
Liu, X., Fan, H. R., Santosh, M., et al., 2012. Remelting of Neoproterozoic Relict Volcanic Arcs in the Middle Jurassic:Implication for the For-mation of the Dexing Porphyry Copper Deposit, Southeastern China. Lithos, 150(10): 85-100. DOI:10.1016/j.lithos.2012.05.018
Ludwig, K. R., 2003. Isoplot/EX Version 3.0, A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronology Center Special Publication, Berkeley.
Mao, J. W., Chen, M. H., Yuan, S. D., et al., 2011. Geological Characteristics of the Qinhang (or Shihang) Metallogenic Belt in South China and Spatial-Temporal Distribution Regularity of Mineral Deposits. Acta Geologica Sinica, 85(5): 636-658.
Mao, J. W., Xie, G. Q., Guo, C. L., 2008. Spatial-Temporal Distribution of Mesozoic Ore Deposits in South China and Their Metallogenic Settings. Geological Journal of China Universities, 14(4): 510-526.
Martin, H., Bonin, B., Capdevila, R., et al., 1994. The Kuiqi Peralkaline Granitic Complex (SE China):Petrology and Geochemistry. Journal of Petrology, 35(4): 983-1015. DOI:10.1093/petrology/35.4.983
Ohmoto, H., 1972. Systematics of Sulfur and Carbon Isotopes in Hydro-thermal Ore Deposits. Economic Geology, 67(5): 551-578. DOI:10.2113/gsecongeo.67.5.551
Ohmoto, H., Rye, R. O., 1979. Isotopes of Sulfur and Carbon. In: Barnes, H. L., ed., Geochemistry of Hydrothermal Ore Deposits. Wiley-Interscience, New York. 509-567
Peng, S. B., Jin, Z. M., Fu, J. M., et al., 2006. The Geochemical Evidences and Tectonic Significance of Neoproterozoic Ophiolite in Yunkai District, Western Guangdong Province, China. Acta Geologica Sinica, 80(6): 814-825.
Qin, X. F., Pan, Y. M., Li, J., et al., 2006. Zircon SHRIMP U-Pb Geochronology of the Yunkai Metamorphic Complex in Southeastern Guangxi, China. Geological Bulletin of China, 25(5): 553-559.
Qiu, J. S., Wang, D. Z., McInnes, B. I. A., 1999. Geochemistry and Petro-genesis of the I-and A-Type Composite Granite Masses in the Coastal Area of Zhejiang and Fujian Provinces. Acta Petrologica Sinica, 15(2): 237-246.
Qiu, J. S., Xiao, E., Hu, J., et al., 2008. Petrogenesis of Highly Fractionated I-Type Granites in the Coastal Area of Northeastern Fujian Province:Constraints from Zircon U-Pb Geochronology, Geochemistry and Nd-Hf Isotopes. Acta Petrologica Sinica, 24(11): 2468-2484.
Scherer, E., Muenker, C., Mezger, K., 2001. Calibration of the Lutetium-Hafnium Clock. Science, 293(5530): 683-687. DOI:10.1126/science.1061372
Segal, I., Halicz, L., Platzner, I. T., 2003. Accurate Isotope Ratio Measure-ments of Ytterbium by Multiple Collection Inductively Coupled Plasma Mass Spectrometry Applying Erbium and Hafnium in an Improved Double External Normalization Procedure. Journal of Analytical Atomic Spectrometry, 18(10): 1217-1223. DOI:10.1039/b307016f
Sharma, R., 2001. Indian Deep-Sea Environment Experiment (Index):A Study for Environmental Impact of Deep Seabed Mining in Central In-dian Ocean. Deep-Sea Research Ⅱ, 48: 3295-3426. DOI:10.1016/S0967-0645(01)00041-8
Tang, L. M., Chen, H. L., Dong, C. W., et al., 2010. Late Mesozoic Tectonic Extension in SE China:Evidence from the Basic Dike Swarms in Hainan Island, China. Acta Petrologica Sinica, 26(4): 1204-1216.
Tang, Y. L., 2009. Geological Characteristics and Ore Controlling Factors of the Songwang W-Sn-Mo Deposit in Bobai County, Guangxi Province. Mineral Resources and Geology, 23(2): 158-162.
Wan, Y. S., Liu, D. Y., Wilde, S. A., et al., 2010. Evolution of the Yunkai Terrane, South China:Evidence from SHRIMP Zircon U-Pb Dating, Geochemistry and Nd Isotope. Journal of Asian Earth Sciences, 37(2): 140-153. DOI:10.1016/j.jseaes.2009.08.002
Wang, D. H., Chen, Y. C., Chen, W., et al., 2010. Dating of the Dachang Superlarge Tin-Polymetallic Deposit in Guangxi and Its Implication for the Genesis of the No. 100 Orebody. Acta Geologica Sinica-English Edition, 78(2): 452-458. DOI:10.1111/j.1755-6724.2004.tb00153.x
Wang, D. Z., Shen, W. Z., 2003. Genesis of Granitoids and Crustal Evolution in Southeast China. Earth Science Frontiers, 10(3): 209-220.
Wang, L. J., Griffin, W. L., Yu, J. H., et al., 2010. Precambrian Crustal Evolution of the Yangtze Block Tracked by Detrital Zircons from Neo-proterozoic Sedimentary Rocks. Precambrian Research, 177(1/2): 131-144. DOI:10.1016/j.precamres.2009.11.008
Wang, Q., Zhao, Z. H., Jian, P., et al., 2005. Geochronology of Cretaceous A-Type Granitoids or Alkaline Intrusive Rocks in the Hinterland, South China:Constraints from Late Mesozoic Tectonic Evolution. Acta Pet-rologica Sinica, 21(3): 795-808.
Wang, Y., Zhu, X. K., Mao, J. W., et al., 2011. Iron Isotope Fractionation during Skarn-Type Metallogeny:A Case Study of Xinqiao Cu-S-Fe-Au Deposit in the Middle-Lower Yangtze Valley. Ore Geology Reviews, 43(1): 194-202. DOI:10.1016/j.oregeorev.2010.12.004
Wang, Y. J., Fan, W. M., Zhang, G. W., et al., 2013. Phanerozoic Tectonics of the South China Block:Key Observations and Controversies. Gondwana Research, 23(4): 1273-1305. DOI:10.13039/501100002367
Wang, Y. J., Fan, W. M., Zhao, G. C., et al., 2007. Zircon U-Pb Geochro-nology of Gneissic Rocks in the Yunkai Massif and Its Implications on the Caledonian Event in the South China Block. Gondwana Research, 12(4): 404-416. DOI:10.1016/j.gr.2006.10.003
Wang, Y. J., Wu, C. M., Zhang, A. M., et al., 2012. Kwangsian and Indosinian Reworking of the Eastern South China Block:Constraints on Zircon U-Pb Geochronology and Metamorphism of Amphibolites and Granulites. Lithos, 150(5): 227-242. DOI:10.1016/j.lithos.2012.04.022
Wang, Y. J., Zhang, A. M., Fan, W. M., et al., 2011. Kwangsian Crustal Anatexis within the Eastern South China Block:Geochemical, Zircon U-Pb Geochronological and Hf Isotopic Fingerprints from the Gneissoid Granites of Wugong and Wuyi-Yunkai Domains. Lithos, 127(1/2): 239-260. DOI:10.1016/j.lithos.2011.07.027
Wiedenbeck, M., Alle, P., Corfu, F., et al., 1995. Three Natural Zircon Standards for U-Th-Pb, Lu-Hf, Trace Element and REE Analyses. Ge-ostandards Newsletter, 19(1): 1-23. DOI:10.1111/j.1751-908X.1995.tb00147.x
Woodhead, J., Hergt, J., Shelley, M., et al., 2004. Zircon Hf-Isotope Analysis with an Excimer Laser, Depth Profiling, Ablation of Complex Ge-ometries, and Concomitant Age Estimation. Chemical Geology, 209(1/2): 121-135. DOI:10.1016/j.chemgeo.2004.04.026
Wu, J., Liang, H. Y., Huang, W. T., et al., 2012. Indosinian Isotope Ages of Plutons and Deposits in Southwestern Miaoershan-Yuechengling, Northeastern Guangxi and Implications on Indosinian Mineralization in South China. Chinese Science Bulletin, 57(9): 1024-1035. DOI:10.1007/s11434-011-4968-z
Wu, L. S., Zou, X. Q., 1997. Re-Os Isotopic Age Study of the Chengmenshan Copper Deposit, Jiangxi Province. Mineral Deposits, 16(4): 376-381.
Xiao, E., Qiu, J. S., Xu, X. S., et al., 2007. Geochronology and Geochemistry of the Yaokeng Alkaline Granitic Pluton in Zhejiang Province:Petrogenetic and Tectonic Implications. Acta Petrologica Sinica, 23(6): 1431-1440.
Xie, G. Q., Hu, R. Z., Jia, D. C., 2002. Geological and Geochemical Characteristics and Its Significance of Mafic Dikes from Northwest Jiangxi Province. Geochimica, 31(4): 329-337.
Xu, B., Jiang, S. Y., Wang, R., et al., 2015. Late Cretaceous Granites from the Giant Dulong Sn-Polymetallic Ore District in Yunnan Province, South China:Geochronology, Geochemistry, Mineral Chemistry and Nd-Hf Isotopic Compositions. Lithos, 218-219: 54-72. DOI:10.1016/j.lithos.2015.01.004
Xu, X. S., Zhou, X. M., O'Reilly, Y. S., et al., 1999. Genesis of Granitoids and Crustal Evolution in Southeast China. Acta Petrologica Sinica, 15(2): 217-223.
Xu, Y. M., Jiang, S. Y., Zhu, Z. Y., et al., 2012. Geochronology, Geochemistry and Mineralization of the Quartz Diorite-Porphyrite and Granodiorite Porphyry in the Shanshangwan Area of the Jiurui Ore District, Jiangxi Privince. Acta Petrologica Sinica, 28(10): 3306-3324.
Xu, Y. M., Jiang, S. Y., Zhu, Z. Y., et al., 2013. Geochronology, Geochemistry and Mineralogy of Ore-Bearing and Ore-Barren Intermediate-Acid Intrusive Rocks from the Jiurui Ore District, Jiangxi Province and Their Geological Implications. Acta Petrologica Sinica, 29(12): 4291-4310.
Yang, S. Y., Jiang, S. Y., Li, L., et al., 2011. Late Mesozoic Magmatism of the Jiurui Mineralization District in the Middle-Lower Yangtze River Metallogenic Belt, Eastern China:Precise U-Pb Ages and Geodynamic Implications. Gondwana Research, 20(4): 831-843. DOI:10.1016/j.gr.2011.03.012
Yang, Z., Liu, R., Wang, X., et al., 2014. Petrogenesis and Tectonic Significance of Late Yanshanian Granites in the Yunkai Area, Southeast China:Evidence from Zircon U-Pb Ages and Lu-Hf Isotopes. Earth Science-Journal of China University of Geosciences, 39(9): 1258-1276.
Ye, Z. G., 2005. Geological Characteristics and Ore Controlling Factors of the Sanchachong W Deposit in Bobai County, Guangxi Province. Land and Resources of Southern China, 12: 31-34.
Yu, J. H., O'Reilly, S. Y., Wang, L. J., et al., 2008. Where was South China in the Rodinia Supercontinent?. Precambrian Research, 164(1/2): 1-15. DOI:10.1016/j.precamres.2008.03.002
Yu, J. H., O'Reilly, S. Y., Wang, L. J., et al., 2010. Components and Episodic Growth of Precambrian Crust in the Cathaysia Block, South China:Evidence from U-Pb Ages and Hf Isotopes of Zircons in Neoproterozoic Sediments. Precambrian Research, 181(1-4): 97-114. DOI:10.1016/j.precamres.2010.05.016
Yu, M. G., Xing, G. F., Shen, J. L., et al., 2006. Chronologic Study on Volcanic Rocks in the Mt. Yandangshan World Geopark. Acta Geologica Sinica, 80(11): 1683-1690.
Yui, T. F., Okamoto, K., Usuki, T., et al., 2009. Late Triassic-Late Cretaceous Accretion/Subduction in the Taiwan Region along the Eastern Margin of South China-Evidence from Zircon SHRIMP Dating. International Geology Review, 51(4): 304-328. DOI:10.1080/00206810802636369
Zhang, F. F., Wang, Y. J., Zhang, A. M., et al., 2012. Geochronological and Geochemical Constraints on the Petrogenesis of Middle Paleozoic (Kwangsian) Massive Granites in the Eastern South China Block. Lithos, 150(5): 188-208. DOI:10.1016/j.lithos.2012.03.011
Zhao, K. D., Jiang, S. Y., Jiang, Y. H., et al., 2006. SHRIMP U-Pb Dating of the Furong Unit of Qitangling Granite from Southeast Hunan Province and Their Geological Implications. Acta Petrologica Sinica, 22(10): 2611-2616.
Zhao, K. D., Jiang, S. Y., Yang, S. Y., et al., 2012. Mineral Chemistry, Trace Elements and Sr-Nd-Hf Isotope Geochemistry and Petrogenesis of Cailing and Furong Granites and Mafic Enclaves from the Qitianling Batholith in the Shi-Hang Zone, South China. Gondwana Research, 22(1): 310-324. DOI:10.1016/j.gr.2011.09.010
Zhong, K. B., Huang, F. Y., 2007. Geological Characteristics and Prospecting Potential of the Michang W-Mo Deposit in Luchuan County, Guangxi Province. Land and Resources of Southern China, 9: 27-31.
Zhou, Q., Jiang, Y. H., Liao, S. Y., et al., 2012. SHRIMP Ziron U-Pb Dating and Hf Isotope Studies of the Diroite Porphyrite from the Dexing Copper Depoist. Acta Geologica Sinica, 86(11): 1726-1734.
Zhou, X. M., Sun, T., Shen, W. Z., et al., 2006. Petrogenesis of Mesozoic Granitoids and Volcanic Rocks in South China:A Response to Tectonic Evolution. Episodes, 29(1): 26-33.
Zhou, X. W., Cui, S. Q., Wen, J., et al., 2009. Re-Os Isotope Dating of the Liguifu Tungsten-Tin Polymetallic Deposit in Dupangling Area, Guangxi. Geology in China, 36(4): 837-844.
Zhou, Y. Z., Zhen, Y., Zeng, C. Q., et al., 2015. On the Understanding of Qinzhou Bay-Hangzhou Bay Metallogenic Belt, South China. Earth Science Frontiers, 22(2): 1-6.
Zhu, X. K., Li, Z. H., Tang, S. H., et al., 2008. Fe Isotope Characteristics of Early Precambrian Pyrite Deposits and Their Geological Significance:Examples from Shandong and Hebei Provinces. Acta Petrologica et Mineralogica, 27(5): 429-434.