Fluid-zircon interaction during low-temperature hydrothermal processes: Implications for the genesis of the Banxi antimony deposit, South China

Journal Pre-proofs Fluid–zircon interaction during low-temperature hydrothermal processes: Implications for the genesis of the Banxi antimony deposit, South China Huan Li, Zhe-Kai Zhou, Noreen J. Evans, Hua Kong, Qian-Hong Wu, XiaoShuang Xi PII: DOI: Reference:

S0169-1368(19)30411-1 https://doi.org/10.1016/j.oregeorev.2019.103137 OREGEO 103137

To appear in:

Ore Geology Reviews

Received Date: Revised Date: Accepted Date:

5 May 2019 6 September 2019 19 September 2019

Please cite this article as: H. Li, Z-K. Zhou, N.J. Evans, H. Kong, Q-H. Wu, X-S. Xi, Fluid–zircon interaction during low-temperature hydrothermal processes: Implications for the genesis of the Banxi antimony deposit, South China, Ore Geology Reviews (2019), doi: https://doi.org/10.1016/j.oregeorev.2019.103137

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Fluid–zircon interaction during low-temperature hydrothermal processes: Implications for the genesis of the Banxi antimony deposit, South China Huan Li1*, Zhe-Kai Zhou2, Noreen J. Evans3, Hua Kong1, Qian-Hong Wu1, Xiao-Shuang Xi1 1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education; School of Geosciences and Info-Physics, Central South University, Changsha 410083, China 2. Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan 3. School of Earth and Planetary Science, John de Laeter Centre, Curtin University, Bentley 6845, Australia *Corresponding author (H. Li): [email protected]

Abstract Fluid-zircon interaction in hydrothermal systems may provide key information on fluid characterization and ore precipitation. In this study, in situ analyses of Hf isotopes in zircon, combined with U–Pb ages and major and trace element data, provide new insights into fluid genesis at the Banxi antimony deposit. The zircons separated from typical quartz-stibnite ores and altered wall rocks have undergone fluid modification to different degrees, showing hydrothermal overprints in reflected/transmitted light, back scattered electron (BSE) and cathodoluminescence (CL) images and variable concentrations of Si, Zr, Hf, U, Th, Pb, Ti, Nb, Ta, P, F, Y

and rare earth elements. They possess identical U–Pb ages to the Banxi Group and underlying Lengjiaxi Group clastic rocks but distinct 176Yb/177Hf

176Hf/177Hf, 176Lu/177Hf

and

ratios, indicating the possible changing of Lu–Hf systematics during the

hydrothermal alteration. The evidence suggests a contribution of ore material from the Banxi Group and a deeper fluid source, derived from the Lengjiaxi Group and the crystalline basement beneath it. A fluid mixing model is proposed wherein the deep-sourced, high radiogenic Hf fluid mixed with circulating near-surface meteoric component-dominated

fluid,

triggering

antimony

precipitation.

The

U–Pb

chronometer was not reset during this low-temperature mineralization event whereas the Lu–Hf systematics in the fluid-altered zircons show evidence of lattice breakdown of the old zircons during fluid mixing, coupled with external input of highly radiogenic Hf from the crystalline basement. This research highlights the potential to use zircon structure and geochemistry in tracing complex fluid evolutionary processes. Key words: Hydrothermal zircon; Hf isotope; Zircon geochemistry; Xuefengshan; Jiangnan Orogeny

1. Introduction The chemically resistant and refractory nature of the common accessory mineral zircon makes it the ideal choice for age and provenance studies (Kemp et al., 2007; Belousova et al., 2010). The U–Pb and Lu–Hf systematics in zircons are difficult to decouple given the very high closure temperatures and very slow diffusion rate characteristics of these isotopic schemes (Cherniak et al., 1997; Cherniak and Watson, 2001). Hf forms an integral part of the zircon lattice and is therefore very resistant to mobility and contamination (Lenting et al., 2010). In fact, it is generally believed that

the Lu–Hf system is more resistant to alteration processes than the U–Pb system (Kinny and Maas, 2003; Luais et al., 2009). However, some recent studies suggest that U–Pb and Lu–Hf isotope systems in zircons can be decoupled during hydrothermal alteration and metamorphic process (Gerdes and Zeh, 2009; Xiong et al., 2012). During fluid-zircon interaction, the Lu–Hf isotopes become mobile, shedding light on the genesis and physicochemical conditions of the fluid (Liu et al., 2014; Kozlik et al., 2016). Hafnium isotopes, combined with U–Pb dating and major and trace element data for zircon, may be used to characterize fluids and fluid processes responsible for hydrothermal alteration and mineralization (Valley et al., 2010). Based on studies of the garnet effect on zircons (Zheng et al., 2005; Sheng et al, 2012), the behavior of Lu–Hf during metamorphic processes has been intensively studied (e.g., Wu et al., 2006, 2007; Zeh et al., 2010; Zhao et al., 2016). In contrast, the zircon U–Pb and Lu–Hf isotopic and major–trace element behavior, especially the mechanisms that cause element/isotope transport/substitution in zircons during ore formation-related hydrothermal process (exemplified by fluid-zircon interaction), is still not clear. In recent years, back scattered electron (BSE), cathodoluminescence (CL), electron probe microanalysis (EPMA) and laser ablation (multi-collector) inductively coupled plasma-mass spectroscopy (LA-(MC)-ICPMS) analyses have made a great progress in determining the textures and element-isotope distributions in zircons, providing a feasible way to portray the complex magmatic-hydrothermal process worldwide (Sun et al., 2017; Girei et al., 2019; Li et al., 2019a; Jiang et al., 2019). Represented by the Banxi antimony deposit, a large number of low-temperature hydrothermal deposits are widely and intensively developed within and around the Neoproterozoic Jiangnan Orogeny in South China (Fig. 1; Hu and Zhou, 2012; Hu et

al., 2016). These deposits contain huge Sb, Hg and Au resources and are primarily hosted by, or spatially associated with Neoproterozoic epimetamorphic rocks (Peng et al., 2003a, b; Fu et al., 2016; Li et al., 2016). Though considerable research has been carried out on these deposits, the genetic relationship between ore formation and Neoproterozoic basement is still controversial (Peng and Frei, 2004; Peng et al., 2008; Zhang et al., 2016), and the origin of the fluid responsible for the large-scale low-temperature metallogenetic events is still under heated debate (Fan et al., 2004; Yang et al., 2006a. b; Gu et al., 2007; Chen et al., 2012; Liang et al., 2014). For the Banxi Sb deposit, though some geochemical studies have been carried out on the ores (e.g., Li et al., 2018a), the fluid source and evolutionary process is still not clear, and the genesis of this deposit still deserves further investigation. The changing mechanism of U–Pb and Lu–Hf isotopes as well as major and trace element compositions in hydrothermally altered zircons and the implications for fluid evolution are not well documented to date. In addition, a geochemical and minerogenetic understanding of the large-scale, low-temperature mineralization events in South China is hindered by our inability to predict the ore forming process or determine the fluid source. In this study, zircon BSE and CL imaging, EPMA and LA-(MC)-ICPMS U–Pb dating, trace element and Hf analyses were carried out on typical stibnite-quartz ores, altered wall rocks and unaltered wall rocks from the Banxi antimony deposit. We aim to reveal the zircon U–Pb and Lu–Hf isotopic and major and trace elemental behavior under complex fluid conditions, providing direct geochemical constraints on the ore-forming process and establishing an ore-forming model for the Banxi deposit. The results will offer new insights into the properties of minerogenetic fluids in low-temperature ore deposits within and around the Jiangnan Orogeny.

2. Regional Geology South China is composed of the Yangtze Block to the northwest and the Cathaysian Block to the southeast, separated by the Jiangnan orogeny (Fig. 1). The Jiangnan Orogeny, usually described as the Jiangnan domain or Jiangnan fold belt in Chinese literature, is a suture belt and assumed to record continent–arc–continent collision between the Yangtze Block and the Cathaysian Block in the early Neoproterozoic, following the Grenvillian subduction of oceanic crust in the late Mesoproterozoic (Zheng et al., 2007; Su et al., 2017; Li et al., 2019b). This orogeny is dominated by early Neoproterozoic metamorphosed volcanic-sedimentary strata (e.g., the Sibao Group in north Guangxi) which were intruded by middle Neoproterozoic peraluminous

(S-type)

granites

and

unconformably

overlain

by

middle

Neoproterozoic weakly metamorphosed strata (e.g., the Banxi Group in central and western Hunan) and late Neoproterozoic unmetamorphosed Sinian cover (Zheng et al., 2008; Zhang et al., 2012; Zhao and Cawood, 2012). The giant South China low-temperature ore domain covers an area of ~ 500,000 km2 in the southwestern Yangtze Block, and is composed of three ore provinces (Chuan-Dian-Qian Pb–Zn, Youjiang Au–As–Sb–Hg, and central-western Hunan Sb–Au; Fig. 1; Hu et al., 2016). Numerous Carlin-type gold, MVT Pb–Zn and vein-type Sb, Hg and As deposits were formed under low-temperature conditions (mostly 100–250 oC), hosted by sedimentary rocks and obviously controlled by fault and fracture systems (Peng and Dai, 1999; Hu et al., 2002; Su et al., 2009; Zhu and Peng, 2015; Chen et al., 2018). The Sb reserve in the domain accounts for 50% of the total reserves in the world, while the domain holds 10% and 80% of the Au and Hg reserves in China, respectively, and Pb–Zn are also major products (Tu, 2002; Zhao and Tu, 2003). Recent studies have shown that the Sb–Au–W deposits developed in

the weakly metamorphosed Precambrian clastic rocks were formed 435–380 Ma during the late Caledonian orogeny (Peng et al., 2003a), and the other deposits were dominantly formed 230–200 Ma and 160–130 Ma, corresponding to Triassic and Jurassic–Cretaceous orogenies in South China (Hu et al., 2016). The low-temperature ore belt in the central-western Hunan consists of two types of deposits, differentiated by their host rocks (Fig. 2; Table 1). The first type is hosted by weakly metamorphosed Precambrian clastic rocks, outcropped along the Xuefeng Mountain region of the Jiangnan Orogeny, and represented by the Woxi Au–Sb–W, Zhazixi W–Sb and Fuzhuxi Sb–Au deposits. These vein-type deposits are characterized by co-mineralization of Sb with Au and/or W, mainly hosted by the Banxi Group and Lengjiaxi Group, dominantly of Ordovician-Devonian (435–380 Ma) and Late Triassic (230–200 Ma) mineralization ages. Typical ore mineral assemblages contain native gold, stibnite, pyrite, arsenopyrite, tetrahedrite, scheelite, wolframite and minor sphalerite, galena, chalcopyrite and chalcocite (Table 1). Gangue minerals are mainly quartz, followed by sericite, ankerite, calcite, chlorite and a minor amount of pyrophyllite, albite, K-feldspar, kaolinite, illite, apatite and zircon. The Middle Proterozoic Lengjiaxi Group is composed of a series of lower greenschist facies gray-green sandstone, siltstone, slate and tuffaceous slate, with a range of thickness from 800 to 25,000 m. It locally shows characteristic turbidite features such as Bouma sequences and convolute bedding, containing thick successions (up to 5000 m) of volcanic rocks (including tholeiitic pillow lava, quartz keratophyre and spilite) in its lower part (Gu et al., 2012). Recent detrital zircon U–Pb dating constrained the depositional age of the Lengjiaxi Group at 860–820 Ma (Wang et al., 2007, 2016; Meng et al., 2013). The Upper Proterozoic Banxi Group is a set of terrigenous clastic rocks interbedded with pyroclastic turbidites, largely composed of lower greenschist

facies gray-green tuff and purplish-red graywacke, siltstone, sandy slate and slate, with a thickness of 1250–6200 m (Chen et al., 2012; Gu et al., 2012). It rests unconformably on the Lengjiaxi Group and can be divided into two units; the lower Madiyi Formation and the upper Wuqiangxi Formation. Detrital zircon U–Pb dating yielded a deposit age of 820–725 Ma for the Banxi Group (Zhang et al., 2008a, b) The second type of Sb deposit in the central-western Hunan Sb–Au province is hosted by Devonian carbonates or calcareous clastic rocks, represented by the giant Xikuangshan Sb deposit which was formed during Late Jurassic–Early Cretaceous (160–130 Ma) (Fig. 2; Table 1). These deposits are mostly Sb-mineralized only, with stibnite as the ore mineral. Trace amounts of pyrite, pyrrhotite and sphalerite also occur in the ore (Fan et al., 2004) with gangue minerals including quartz and calcite, and small amounts of fluorite, barite and secondary gypsum (Table 1). The alteration of the host limestone is dominated by silicification, and subordinately by carbonatization, fluoritization and baritization (Peng et al., 2003b). The exposed strata in the Xikuangshan region are predominantly Middle-Upper Devonian and Lower Carboniferous carbonates, locally interbedded with siltstone, argillite and shale.

3. Deposit geology The Banxi antimony deposit is located at the southeast margin of the Jiangnan Orogeny (Fig. 2). It is the representative vein-type antimony deposit in central-western Hunan and has a long mining history (> 100 years), with a total Sb reserve of ~ 100,000 tons. The ore veins and outcropped strata in this deposit are controlled by a NNEE-striking fault (F1) and a NEE-trending anticline (Jiangjiachong) (Fig. 3a). The F1 fault, also known as the Dafuping fault, is considered to be a deep structure with a steep dip angle of > 70o (Fig. 3b). Dozens of secondary faults are

developed on both sides of the major F1 fault, intersecting the F1 plane and extending along the axis of the Jiangjiachong anticline. These steeply dipping secondary fractures are the host structures of ore body veins and are marked in Fig. 3a. The outcropping strata in the Banxi area belong to the Wuqiangxi Formation, a set of epimetamorphic clastic rocks with original characteristics of a littoral facies-neritic facies flysch sedimentary sequence. It can be further divided into three members from bottom to top (Fig. 3b). Located at the core of the Jiangjiachong anticline, the first member is composed of grey–green meta-sedimentary tuff (Fig. 4a), tuffaceous siltstone, tuffaceous slate, sericite slate and sandy slate, locally interbedded with feldspathic quartz sandstone. Outcropping at the wings of the Jiangjiachong anticline, the second member consists of thick-bedded tuff, tuffaceous slate (Fig. 4b), sericite slate and tuffaceous sericite slate from bottom to top. The third member contains silty slate, purple slate, banded slate (Fig. 4c), sericite slate and silty sericite slate. It is interbedded with tuffaceous slate near the base, meta-tuff in the medium sections and meta-sandstone in the upper portions. This member is mostly located at, and just beyond, the wings of the Jiangjiachong anticline. The first and the second members are the ore-bearing strata for the Sb deposit with the tuff and tuffaceous slate making up the major host rocks. The most recent research has dated the Banxi Group Wuqiangxi Formation tuffaceous rocks at 770–766 Ma (Li et al., 2019b). Among the dozens of Sb ore veins, only the No. 2 vein in the Jiangjiachong anticline region is being mined, and is the largest sized and most representative ore vein in the Banxi mining area. It has an elongated “S" shape in the plane and a full-length of over 1000 m. It consists of three relatively independent, discontinuous and left-slip developed ore bodies named No. 2-1, No. 2-2 and No. 2-3 from NE to SW in the section (Fig. 3a). The No. 2 vein has a variable strike direction (45–80o)

and dip angle (45–89o), with a typical thickness ranging from 0.3 to 1 m. Four stages of mineralization can be differentiated for the deposit based on the intersection relationship of ore veins and generation sequence of gangue- and ore-minerals: 1) quartz (Fig. 4d); 2) quartz-sulfide (Fig. 4e); 3) stibnite-sulfide (Fig. 4f); and 4) carbonate (Fig. 4g). Among them, the quartz-sulfide stage is the most important, well-developed mineralization stage. Wall-rock alteration includes silicification (Fig. 4h), arsenopyritization and pyritization (Fig. 4i). The latest geochronological research on the mineralization indicated that the Banxi Sb deposit formed at ~130 Ma (Li et al., 2018a).

4. Samples and analytical techniques Two quartz-stibnite ore samples, BX4-5 (Fig. 5a) and BX4-6 (Fig. 5b), and one hydrothermally altered wall rock sample (BX7-3, Fig. 5c) and some unaltered wall rock samples (BX6-2 and BX6-9) were collected from underground tunnels of the Banxi Sb deposit. Since the ore types and mineralization stages are relatively simple and ore veins at different mine levels have similar occurrence at Banxi, these five samples can largely represent the actual geological section from ore body to alteration zone and then to wall rock. Sample BX4-5 was taken from the No. 2-3 ore vein at Level no. 15 (–415 m). It is a typical quartz-stibnite ore containing subhedral stibnite (Fig. 5d), representing the early products of the quartz-sulfide stage. Sample BX4-6 was collected from Stope no. 1506 at Level no. 14 (–375 m). It is also a quartz-sulfide ore containing euhedral-subhedral stibnite (~ 20%) and euhedral arsenopyrite (~ 5%) (Fig. 5e), representing the late products of the quartz-sulfide stage. The early and late stages of the quartz-sulfide stage were differentiated through field relations, spatial locations and petrography: the early stage quartz-sulfide ore is located deeper with

less euhedral and smaller stibnite. Sample BX7-3 was collected at Level no. 10 (–200 m), which is the host rock of the No. 2-3 vein. It is a weakly metamorphosed, heavily silicified sedimentary tuff with parallel sulfide veinlets crosscutting the rock (Fig. 5f). Unaltered wall rocks (BX6-2 and BX6-9) were sampled far away from ore veins at the deposit. Zircon crystals were separated using standard techniques, hand-picked under a binocular microscope, mounted in epoxy resin, and polished to expose the grain center. Reflected light, transmitted light and Cathodoluminescence (CL) images were taken for all the mounted zircons at Beijing Geo-Analysis Co., Ltd, using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS) system and a CL3+ detector and operated at 15 kV and 20 nA. In addition, BSE imaging were carried out for zircons at the State Key Laboratory of Geological Processes and Mineral Resources (GPMR), China University of Geosciences (Wuhan). By examining these photomicrographs, zircon internal structures were studied and those without visible fluid/mineral inclusions and cracks were chosen for U–Pb and Hf analysis. Zircon major composition was determined in situ using EPMA at the School of Geosciences and Info-physics, Central South University (China). Zircon regions with clean polished surface and no fluid/mineral inclusions were chosen for the analysis. The instrument is a Shimadzu EPMA-1720H equipped with an energy dispersive spectroscopy (EDS), using a 15 kV accelerating voltage, 20 nA beam current, and electron beam of 5 μm in diameter during the analysis. The Xray lines used to analyze the various elements were F (Kα), Si (Kα), P (Kα), Y(Lα), Zr (Lα), Dy (Lα), Er (Lα), Lu (Lα), Hf (Lα), Th (Mα) and U (Mα). The following artificial standards or natural crystals were used as reference materials: apatite (Ca5(PO4)) for F and P, zircon

(ZrSiO4) for Si, Zr and Hf, yttrium aluminous garnet for Y, pure REE crystals Dy, Er and Lu, thorite (ThSiO4) for Th and pure uranium dioxide (UO2) for U. All the resulting data were corrected using the ZAF approach. Zircon U–Pb dating and trace element analyses were conducted by LA-ICPMS at GPMR where a GeoLas 2005 excimer laser ablation system was coupled to an Agilent 7500a ICPMS. The ablation spots for the LA-ICPMS analysis were situated over the EPMA analysis positions on each grain. Laser frequency and energy were 8 Hz and 70 mJ, respectively, with a spot size of 32 μm and ablated depth of 20–40 μm. The sample cell was flushed with ultrahigh purity He and N2 and high purity Ar was employed as the plasma carrier gas (Hu et al., 2008). Each analysis incorporated a background acquisition of approximately 20–30 s followed by 50 s data acquisition from the sample. Zircon 91500 was used as the external standard for U–Pb dating, and was analyzed twice every five samples. In addition, zircon standard GJ-1 was analyzed as an unknown. The weighted mean 206Pb/238U age for GJ-1 is 597.5±5.3 Ma (2σ, n = 10), which is consistent with the recommended values within uncertainty (599.8±1.7 Ma (2σ) (Jackson et al., 2004). Time-dependent drifts of U–Th–Pb isotopic ratios were corrected using a linear interpolation (with time) for every five analyses according to variations in the 91500 standard. Preferred U–Th–Pb isotopic ratios used for 91500 were from Wiedenbeck et al. (2004). In addition, to correct for time-dependent drift of sensitivity and mass discrimination in trace element results, every 10 sample analyses were followed by one analysis of NIST SRM 610. Trace element compositions of zircons were calibrated against multiple reference materials (BCR-2G and BIR-1G), combined with internal standardization (29Si, assumed 32.7 % SiO2 for zircon unknowns). Detailed analytical conditions and methods for LA-ICPMS trace element analyses are described in Liu et al. (2008) and Chen et al.

(2011). Off-line selection and integration of background and analytical signals, time-drift correction, and quantitative calibration for zircon U–Pb dating and trace element compositions were performed using ICPMSDataCal 8.3 (Liu et al., 2010). Common Pb was corrected based on the method proposed by Andersen (2002). Concordia diagrams and weighted mean ages were calculated using Isoplot 4.5 (Ludwig, 2003). In-situ analysis of zircon Lu–Hf isotopes was carried out by laser ablation-multi collector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS) at GPMR, with a spot size of 44 μm, a repetition rate of 10 Hz, and an energy density of 5.3 J/cm2. The ablation spots for Hf isotope analyses were situated over or close to the U–Pb age analysis positions on each grain. Interference of

176Lu

175Lu,

corrected by measuring the intensity of interference-free recommended 176Lu/177Hf.

176Lu/175Lu

176Hf

was

using the

ratio of 0.02669 (De Biévre and Taylor, 1993) to calculate

The isobaric interference of

recommended

on

176Yb/172Yb

176Yb

on

176Hf

was corrected using a

ratio of 0.5886 (Chu et al., 2002). Detailed operating

conditions and analytical methods for LA-ICPMS and LA-MC-ICPMS are described in Hu et al. (2012). Three different standards zircons (91500, TEM and GJ-1) were measured to correct Hf isotopic values. As the primary reference material, 91500 was analysed twice every 8 unknowns and both GJ-1 and TEM standard zircons were analyzed twice at the beginning and ending of the run. The

176Hf/177Hf

results

obtained for 91500 are within error (0.282308 ± 0.00002 (95% conf.), n = 10) of the recommended Hf isotopic values (0.282306 ± 0.00004) (Wiedenbeck et al., 2004). Off-line selection and integration of analyte signals, and mass bias calibrations were performed using ICPMSDataCal (Liu et al., 2010). A decay constant of 1.867×10–11 y–1 was adopted for

176Lu

(Söderlund et al., 2004). The initial

176Hf/177Hf

ratio,

denoted as εHf(t), was calculated relative to the chondritic reservoir with a 176Hf/177Hf ratio of 0.282785 and

176Lu/177Hf

of 0.0336 (Bouvier et al., 2008). Single stage Hf

model ages (TDM1) were calculated relative to the depleted mantle with a present day 176Hf/177Hf

ratio of 0.28325 and

176Lu/177Hf

of 0.0384 (Vervoort and Blichert-Toft,

1999), and two stage Hf model ages (TDM2) were calculated by assuming a mean 176Lu/177Hf

value of 0.015 for the average continental crust (Griffin et al., 2002).

5. Results 5.1 Reflected/transmitted light, BSE and CL images Reflected light, transmitted light and BSE images are displayed in Fig. 6a–c. zircons from ore samples BX4-5 and BX4-6 are characterized by the presence of magmatic cores and hydrothermal rims (Fig. 6a–b), indicating hydrothermal overprinting. In addition, zircons from ore samples (typified by BX4-6) possess abundant fluid/mineral inclusions such as pyroxene, quartz and stibnite (Fig. 6c). In contrast, zircons from altered wall-rock sample BX7-3 were less modified by fluid, evidenced by their unobvious hydrothermal rims and less abundant fluid/mineral inclusions (Fig. 6 a–c). CL images for all analyzed zircon grains are shown in Fig. 7a–c. Most of the zircons are 50–120 μm in length, with aspect ratios (length/width) ranging from 1:1 to 2:1. Some of the zircons are euhedral and show oscillatory zoning characteristics, indicating a magmatic origin. However, the majority of the zircons are characterized by moderate roundness and irregular internal texture, suggesting a detrital origin. Moreover, some zircon grains are dark in CL images, implying hydrothermal alteration. This characteristic is most obvious in the zircons from sample BX4-6 (Fig. 7b), followed by zircons from sample BX4-5 (Fig. 7a) and less indicated by zircons

from BX7-3 (Fig. 7c). 5.2 Zircon U–Pb ages Zircon LA-ICPMS U–Pb dating results are presented in Table 2. In total 63 U–Pb isotopic analyses were performed for the three samples (20 for sample BX4-5, 20 for sample BX4-6 and 23 for sample BX7-3), and 60 dates were obtained with concordance > 90%. The measured

206Pb/238U

ages for these samples fall into two

main ranges, Neoproterozoic Group 1 (764–865 Ma, dominantly around 770 Ma) and Paleoproterozoic Group 2 (1780–2468 Ma). For sample BX4-5, Group 1 zircons contain six spots with

206Pb/238U

ages ranging from 766–775. They yielded a

concordant U–Pb age of 770 ± 15 Ma (MSWD = 0.10) and a mean age of 771 ± 15 Ma (MSWD = 0.04) (Fig. 8a). Group 2 zircons from sample BX4-5 can be further divided into two sub-groups: 8 spots range from 1780–2092 Ma with a concordant U–Pb age of 1846 ± 130 Ma (MSWD = 1.5) and a mean age of 1904 ± 96 Ma (MSWD = 1.6) (Fig. 8b), and another 3 spots yielding a concordant U–Pb age of 2276 ± 170 Ma (MSWD = 0.22) and a mean age of 2296 ± 110 Ma (MSWD = 0.16) (Fig. 8c). Sample BX4-6 also yielded two age groups: 773–779 Ma and 1800–2468 Ma. The first age group includes six spots which have a concordant U–Pb age of 776 ± 10 Ma (MSWD = 0.04) and a mean age of 775 ± 9 Ma (MSWD = 0.03) (Fig. 8d). The second group can be divided into two subgroups: 4 dates have a concordant U–Pb age of 1985 ± 85 Ma (MSWD = 0.78) and a mean age of 2007 ± 40 Ma (MSWD = 1.6) (Fig. 8e), and the other three very old dates yielded a concordant U–Pb age of 2458 ± 70 Ma (MSWD = 1.1) and a mean age of 2441 ± 63Ma (MSWD = 1.4) (Fig. 8f). In contrast, sample BX7-3 has no Group 2 Paleoproterozoic zircons. Group 1 Neoproterozoic zircons from this sample can be divided into two sub-ranges: fifteen spots with ages ranging from 764–775 Ma yielded a less concordant U–Pb age of 770

± 7 Ma (MSWD = 0.13) and a mean age of 769 ± 13 Ma (MSWD = 0.02) (Fig. 8g), and the other three dates which range from 863 to 865 with a concordant U–Pb age of 864 ± 28 Ma (MSWD = 0.01) and a mean age of 864 ± 48 Ma (MSWD = 0.01) (Fig. 8h). In addition, three zircons in this sample yielded Mesoproterozoic ages; 1040 Ma, 1396 Ma and 1329 Ma (Table 2). 5.3 Zircon major elements Zircon EPMA major element analytical results for sample BX4-5, sample BX7-3 and unaltered Banxi Group wall rock samples (BX6-2 and BX6-9) are shown in Table 3. Overall, the major compositions of zircons among different samples vary in limited ranges and show some regular changing trends in space (i.e., among different sampling locations). From the unaltered Banxi Group wall rock to the ore sample (BX 4-5) and then to the altered wall rock (BX7-3), the F contents increase with the increase of SiO2 + ZrO2 (Fig. 9a), while the HfO2, UO2 and ThO2 compositions decrease with the increase of ZrO2 (Fig. 9b, c, d). The UO2 and ThO2 contents are positively related (Fig. 9e), and the P2O5 contents are also positively associated with the Y2O3 + HREE2O3 compositions, decreasing with the increase of SiO2 + ZrO2 (Fig. 9f, g). In addition, all of the Zr/Hf ratios of these zircons are below the chondritic value, generally decreasing with the increasing of SiO2 + ZrO2 (Fig. 9h). 5.4 Zircon trace and rare earth elements Zircon LA-ICPMS trace and rare earth element analytical results for the three samples are shown in Table 4. Similarly, the trace element contents among different samples are consistent but there is some variability for some elements. Zircons from the three samples have typical Hf concentrations ranging from 1000 to 15000 ppm (Fig. 10), Ti from 2 to 100 ppm (Fig. 10a), Y from 100 to 6000 ppm (Fig. 10b), U

from 50 to 1000 ppm (Fig. 10c), and Th/U ratios from 0.5 to 3 (Fig. 10d). Among them, zircons from sample BX4-5 possess highest average concentrations of Hf (> 10000 ppm), Pb (216 ppm), Th (484 ppm) and U (452 ppm). BX4-6 zircons have highest average contents of Ti (28 ppm) and Th/U ratios (1.29). Zircons from the altered wall rock (sample BX7-3) have lowest average Hf (~ 6000 ppm), Nb (2.3 ppm), Ta (< 1 ppm), Ti (10.1 ppm) and Th/U ratios (1.03) but highest average Y (2014 ppm), distinct from the ore sample zircons. For the REEs, two types of chondrite-normalized patterns can be differentiated from each sample (Fig. 11). The first type (Type 1) shows obvious fractionation between LREE and HREE with pronounced positive Ce anomalies, roughly corresponding to bright oscillatory zoning on their CL images; the second type (Type 2) is characterized by relatively flat REE patterns, less fractionated LREE to HREE, and subtle positive or slightly negative Ce anomalies, mostly consistent with their dark CL images. In addition, there are no obvious differences in the age peaks among these two types of patterns. For sample BX4-5, most of the zircons have the first type of REE patterns with LREE/HREE and Ce/Ce* ratios ranging from 0.02 to 0.13 (average = 0.07) and from 1.50 to 96.72 (average = 17.88), respectively. The second type of REE pattern is shown by grains 2, 3, 4, and 16 from this sample, which possess higher ratios of LREE/HREE (0.07–0.33, average = 0.19) but lower Ce/Ce* (0.54–1.68, average = 0.96) (Fig. 11a). The second type of REE pattern is evident in BX4-6 zircons (grains 1, 5, 8, 11, 13, 16, 17, and 20) which have the highest LREE/HREE (0.05–6.51, average = 1.16) and lowest Ce/Ce* (0.63–1.11, average = 0.78), compared to the lower LREE/HREE (0.02–0.12, average = 0.07) and higher Ce/Ce* (1.41–88.27, average = 24.32) for other grains from sample (Fig. 11b). Differences between these two types of REE patterns are more subtle in BX7-3

zircons, where the first type of REE pattern is manifest in many zircons, with typical LREE/HREE and Ce/Ce* ratios ranging from 0.01 to 0.05 (average = 0.02) and from 0.11 to 20.33 (average = 5.00), respectively. However, several grains (2, 3, 4, 6, and 12) yield the second type of REE pattern with LREE/HREE and Ce/Ce* ratios ranging from 0.07 to 0.14 (average = 0.11) and from 0.52 to 1.17 (average = 0.80), respectively (Fig. 11c). Moreover, it is notable that BX7-3 zircons have highest average concentrations of Yb (571 ppm) and Lu (99 ppm), followed by BX4-5 zircons (469 ppm and 79 ppm, respectively) and BX4-6 zircons (352 ppm and 56 ppm, respectively). 5.5 Zircon Hf isotopes Zircon Hf isotopic analytical results are presented in Table 5. Analysis was performed on 33 zircons with ages ranging from 761 to 2433 Ma with 11 spots for sample BX4-5, 10 for BX4-6, and 12 for BX7-3. Overall, the Lu–Hf isotopic compositions in zircons are quite heterogeneous in each sample and vary largely among distinct age groups and different samples (Fig. 12a, b). For sample BX4-5, Group 1 zircons (764–771 Ma) have generally higher ratios of (0.281559–0.282368),

176Lu/177Hf

(0.001278–0.002138)

and

176Hf/177Hf 176Yb/177Hf

(0.057007–0.103414) than Group 2 zircons (1817–2323 Ma) which possess lower ranges of

176Hf/177Hf

176Yb/177Hf

(0.280955–0.281471),

176Lu/177Hf

(0.000311–0.001092) and

(0.016312–0.056201). Correspondingly, Group 1 zircons have higher

εHf(t) (–26.7 to 1.7) and younger single-stage Hf model ages (TDM1, 1280–2400 Ma) and two-stage Hf model ages (TDM2, 1462–3013 Ma), relative to the lower εHf(t) (–17.0 to –3.8) and older TDM1 (2464–3144 Ma) and TDM2 (2687–3485 Ma) of Group 2 zircons. Sample BX4-6 has similar variations between different age groups: the younger Group 1 zircons (774–779 Ma) are characterized by generally higher

176Hf/177Hf

(0.281852–0.282497),

176Lu/177Hf

(0.000529–0.001904),

176Yb/177Hf

(0.016338–0.055843), and younger TDM1 (1095–1954 Ma) and TDM2 (1271–2663 Ma), compared to the opposite trend of (0.000302–0.000739),

176Yb/177Hf

176Hf/177Hf

(0.281249–0.281344),

176Lu/177Hf

(0.009770–0.023650), TDM1 (2647–2744 Ma) and

TDM2 (2776–3210 Ma) in Group 2 zircons (1994–2433 Ma). The εHf(t) values are more variable for Group 1 (–15.8 to 6.4) and narrow for Group 2 (–9.8 to 2.8). In contrast to the zircons from samples BX4-5 and BX4-6, zircons from sample BX7-3 show different characteristics in terms of Lu–Hf isotopic compositions. The Group 1 zircons (761–774 Ma) from this sample show extremely high ratios of (0.282850–0.283018),

176Lu/177Hf

(0.003258–0.007223)

and

176Hf/177Hf 176Yb/177Hf

(0.082872–0.236787), with very high positive εHf(t) (18.0 to 23.6) and abnormally young TDM1 (364–598 Ma) and TDM2 (252–537 Ma).

6. Discussion 6.1 Origin and alteration of the zircons The moderate roundness of many zircons in this study indicate that they were originally detrital zircons from the Precambrian basement wall rocks. Detrital zircons from the Banxi group in the western and central Hunan region normally have a wide range of ages, typically falling into two spans, 720–820 Ma and 1800–2500 Ma (Zhang et al., 2008a,b; Wang et al., 2010; Meng et al., 2013). The zircon ages of the quartz-stibnite ores reported in this study (Fig. 8a–f) are consistent with the above two ranges, indicating that all the zircons in the ore samples (BX4-5 and BX4-6) were originally from the Banxi Group. Moreover, these zircons are intergrown with or contain some major rock-forming minerals from the Banxi Group clastic rocks, such as biotite and pyroxene (Fig. 6c). This may also suggest a detrital origin from the

Banxi Group for the ore zircons. On the other hand, BX7-3 zircons have distinct age ranges (Fig. 8g–h). The youngest age range (764–775 Ma) in this sample can be attributed to the Banxi Group, whereas the other two older ranges (863–865 Ma) and (1329–1396 Ma) partially overlap with the detrital zircon ages from the Lengjiaxi Group in the central-western Hunan region (Meng et al., 2013). This may imply that BX7-3 zircons are a mixed population from the Banxi and Lengjiaxi Groups, and were sourced much deeper relative to BX4-5 and BX4-6 zircons. Compared to the zircons from unaltered Banxi Group country rocks, the zircons from typical ores and altered country rocks possess higher average contents of F and Si whereas lower average compositions of Th, U, HREE and P (Fig. 9). This may indicate that a F- and Si-rich fluid played an important role during the Sb mineralization, and element substitution occurred in the zircon matrix during the alteration process. The positive correlation between F and SiO2 in zircons reflects the progressive release of F when Si is replaced by other elements (e.g., P), implying F complexation during the hydrothermal process. In addition, previous observations have demonstrated that numerous incompatible elements such as Hf, Th, U, REE, Nb, Ta, Y, P, Ti and Pb are highly mobile in a strongly evolved granitic regime and/or aqueous fluid phase which contains high contents of H2O, Li, B and/or P (Veksler et al., 2005; Horie et al., 2008; Nardi et al., 2013; Li et al., 2018b, c). These elements are intensively enriched in granite-related hydrothermal zircons attributed to fluid-zircon interaction (Hoskin, 2005; Li et al., 2014, 2018d, e; Kozlik et al., 2016). In this study, the opposite trends of these values in the altered zircons indicate that the Banxi hydrothermal system was not directly related to granitic-hydrothermal process. Zircons that suffered hydrothermal alteration often possess abundant fluid/mineral inclusions, show dark characteristics in CL images and have elevated Hf,

Ti and Th/U ratios (Hoskin, 2005; Li et al., 2014, 2017; Wu et al., 2018; Jiang et al., 2018). These features are most obvious in BX4-6 zircons, followed by BX4-5 zircons and least obvious in BX7-3 zircons (Figs. 6 and 10). This may indicate that BX4-6 zircons have suffered the strongest hydrothermal overprint, followed by BX4-5 zircons and then BX7-3 zircons. This inference can be further confirmed by their REE characteristics (Fig. 11): BX4-6 zircons possess the largest number of LREE-enriched patterns (Type 2 REE pattern), followed by BX4-5 zircons and then BX7-3 zircons. Since there is no obvious differences in the age peaks among these two types of REE patterns, the timing and source differences between these two types of zircons can be ruled out; and hydrothermal overprint could be the most likely factor that resulted in the REE differences. Also, the presence of fluid-associated mineral inclusions such as quartz and stibnite in the BX4-6 zircons imply a later stage intense hydrothermal modification recorded by the zircons (Fig. 6c). Zircons that have undergone hydrothermal fluid modification normally have LREE-enriched patterns (Fu et al., 2009). On the ΣREE vs. LREE diagram (Fig. 13a), the zircons from the quartz-stibnite ores show a more pronounced hydrothermal alteration signature. Moreover, there is no correlation between ΣREE and Eu/Eu* for any of the three samples (Fig. 13b), implying that the zircons experienced similar physicochemical conditions in the fluid and that magmatic-hydrothermal process can be excluded (Pettke et al., 2005). On the hydrothermal discrimination diagrams proposed by Hoskin (2005) (Fig. 13c, d), around 20–40% zircons from each sample can be classified as hydrothermal zircons. All of this indicates that these zircons were subjected to a single hydrothermal system and suffered fluid modification to different degrees, typified by the BX4-6 zircons. During hydrothermal processes, Hf, Pb, Th, U, Nb, Ta, and Y become mobile

and can be used to monitor the progress of fluid-zircon interaction (Lichtervelde et al., 2009; Nardia et al., 2013). Among the ore and altered country rock samples, the highest concentrations of Hf, Pb, Th and U in BX4-5 zircons suggest the beginning of the fluid precipitation; and the highest contents of Ti and Th/U ratios in BX4-6 zircons may represent the peak of mineralization. The low contents of Nb, Ta and Hf but high concentrations of Y in BX7-3 zircons suggest that the alteration of the tuff occurred during the final stage of the hydrothermal process. In addition, the large variation of Nb/Ta (Fig. 13e) but small range of Hf/Y (Fig. 13f) in this sample may also indicate that the BX7-3 zircons were precipitated during the last stages of mineralization. Collectively, it can be concluded that the zircons in the quartz-stibnite ores came from the Banxi Group, whereas zircons in the altered tuff may have deeper protolith sources. The detrital zircons were transported by channelized mineralizing fluid and underwent fluid alteration to different degrees. The low-temperature hydrothermal process changed the major and trace element concentrations in zircons but did not reset the U–Pb isotopic system, preserving primary ages. The metal- and zircon-bearing fluid precipitated to form the quartz-stibnite ore vein first (Banxi 4-5 and then BX4-6 in sequence) and then continued to travel into the wall rocks, causing alteration (BX7-3) at a lower temperature. 6.2 Source of high 176Hf/177Hf component The extremely high

176Hf/177Hf

ratios reported for BX7-3 zircons in the present

study call for a radiogenic Hf source during the ore-forming process. Generally, there are

three

possible

Hf

reservoirs

for

zircon

modification:

1)

dissolution-recrystallization of pre-existing zircon (Wu et al., 2007; Zeh et al., 2010); 2) breakdown and reprecipitation of high Lu/Hf minerals (e.g., garnet) in a closed

system (Amelin et al., 2000; Zheng et al., 2005) and 3) external sources in an open system (Zeh and Gerdes, 2014; Zhao et al., 2016). In the Banxi deposit, the dissolution-recrystallization of zircons is not obviously evidenced by the CL images and thus can be ruled out. Moreover, the unaltered zircons (820–725 Ma) from the Banxi group clastic rocks have typical

176Hf/177Hf, 176Lu/177Hf

and

176Yb/177Hf

ratios

ranging from 0.2820 to 0.2827 (Fig. 14a), 0.0005 to 0.002 (Fig. 14b), and 0.02 to 0.07 (Fig. 14c), respectively, with TDM1 ages of 800–1700 Ma (Fig. 14d) (Wang et al., 2010, 2012; Meng et al., 2013). These values are generally consistent with those of BX4-5 and BX4-6 zircons but much different from those of BX7-3 zircons, further excluding

the

possibility

that

high

radiogenic

Hf

isotopes

came

from

dissolution-recrystallization of the Banxi Group zircons. On the other hand, the Banxi Group clastic rocks have only suffered very weak metamorphism (lower greenschist facies) and contain no high Lu/Hf minerals such as garnet. Moreover, whole-rock εNd(t) values of the clastic rocks from the Banxi Group range from –7.3 to 0.3 (Wang et al., 2010), indicating no mantle contribution during the diagenetic process. Thus, a Banxi Group-derived high radiogenic Hf source can be also eliminated. Consequently, external input of radiogenic Hf is the most likely explanation for the extremely high 176Hf/177Hf

ratios in the zircons from the altered tuff.

Some of the zircons in sample BX7-3 have been interpreted as sourced from the Lengjiaxi Group or even deeper. As the outcropping oldest rocks in Hunan Province, the Lengjixi Group suffered weak metamorphism (lower greenschist facies) on the whole but also underwent moderate metamorphism (amphibolite facies) locally (Wang et al., 2003). Moreover, basic-ultrabasic rocks are found in some locations (Zhang and Wang, 2016). Typical crustal rocks have 176Lu/177Hf of ∼0.01 (granite) to ∼0.03 (basalt); garnet has high Lu/Hf (0.1 to 8.0, Duchéne et al., 1997; Scherer et al.,

1997), resulting in very radiogenic 176Hf/177Hf over geologically short periods of time (Valley et al., 2010). Hence, the Lengjiaxi Group garnet-bearing metamorphic rocks and basic-ultrabasic rocks could be the source of the radiogenic Hf. In addition, much older crystalline basement has been proven to exist beneath the Lengjiaxi Group in the central Hunan region (Zhang et al., 2016). The crystalline basement could provide much radiogenic Hf and other radiogenic isotopes (e.g., Sr) during mineralization (Peng et al., 2008). Referred to as the Xuefeng uplift belt in Chinese literature, the Xuefeng Mountain region underwent intensive Caledonian (Cambrian to Silurian), Indosinian (Late Permian to Triassic) and Yanshanian (Jurassic to Cretaceous) tectothermal events to different degrees, resulting in multi-stage deformation, magmatism and mineralization (Chu et al., 2012; Ge et al., 2016). We propose that these tectothermal events were superimposed on the Proterozoic metamorphic-crystalline basement rocks, generating the original fluids responsible for ore formation. These fluids interacted with garnet-bearing rocks during retrograde metamorphism, leaching out rare earth elements and radiogenic Hf. The deep-sourced, high radiogenic Hf-bearing fluids then evolved and migrated into the shallow crust through deep faults, forming the initial hydrothermal solution. 6.3 Genesis of the Sb mineralization: A fluid mixing model The origin and evolution of the fluid that contributed to the large-scale low-temperature metallogenetic events in South China is still controversial. In the central and western Hunan Sb–Au province, wall rock-derived fluids (mainly from the Banxi and Lengjiaxi Groups) and metals have been emphasized by most scholars (e.g., Chen et al., 2012), and crystalline basement contributions have also recently been evoked (e.g., Peng et al., 2008). In the present study, both deep-sourced zircons in

sample BX7-3 and Banxi Group wall rock-related zircons in samples BX4-5 and BX4-6 have been differentiated by differences in CL images and trace element and Hf characteristics. This provides the opportunity to examine the migration and evolution of the ore-forming fluids which contained and interacted with different types of zircons. Here, we propose a fluid mixing model to explain the antimony mineralization at the Banxi antimony deposit (Fig. 15). The crystalline basement-derived, high radiogenic Hf-bearing fluids were circulated by tectothermal events (probably related to granitic intrusion) and leached out a considerable consignment of metals. These initial ore-forming fluids penetrated the Lengjiaxi Group metamorphic rocks along deep faults and incorporated some detrital zircons (e.g., BX7-3 zircons aged 813–899 Ma and 1329–1396 Ma). The zircon-containing fluids then migrated into the shallower Banxi Group, and mixed with circulating, near-surface meteoric component-dominated fluids. The latter was characterized by low temperature and low radiogenic element content and contained ore-forming materials and zircons leached from the Banxi Group. Metal precipitation occurred immediately after mixing of the fluids, forming the earlier quartz-stibnite ore (sample BX4-5) in the deeper portion and latter quartz-stibnite ore in the upper portion (BX4-6). During the early mineralization stage, incomplete fluid mixing meant that the Banxi Group-sourced zircons in the ore (sample BX4-5) were not affected by the deep-sourced, highly radiogenic Hf fluid. As the fluid mixing reaction continued, large amounts of metal were precipitated at the peak of the mineralization, causing a large decrease of Hf and increase of Ti, LREE and Th/U ratios in the co-precipitated zircons (BX4-6). The 176Hf/177Hf, 176Lu/177Hf

and

176Yb/177Hf

ratios decrease zircons from sample BX4-5

through to sample BX4-6 (Fig. 12a, b), indicating that the changing of Lu-Hf

systematics occurred during this process. Subsequently, the residual fluids became more radiogenic and altered the wall rocks, resulting in the very high 176Lu/177Hf

and

176Yb/177Hf

176Hf/177Hf,

ratios recorded by the BX 7-3 zircons. This fluid mixing

model is also supported by previous trace element and S-Sr-Nd-Pb-He-Ar isotopic studies on the stibnite and/or arsenopyrite at the Banxi Sb deposit (Li et al., 2018a), which proved that the deep-sourced, relatively high temperature, rock-reacted fluid mixed with increasing amounts of more oxidized, low temperature meteoric fluids, causing the Sb mineralization. The changing of Lu–Hf systematics in zircons during this low-temperature hydrothermal process may be ascribed to the weak lattice in old zircons. Old zircons often suffer much more radiation damage than young zircons (Pidgeon, 2014). This means that old zircons have weaker and more vulnerable lattices that can be easily broken during hydrothermal processes. This is reflected by sample BX4-6, in which Group 2 zircons (1955–2468 Ma) are mostly dark in CL images (Fig. 7b) and possess more hydrothermal features (e.g., higher LREE) relative to Group 1 zircons (774–779 Ma). During fluid mixing, the dramatically changed physicochemical conditions led to breakdown of the lattice in older inherited zircons and intense fluid-zircon interaction which migrated Hf isotopes and other elements in and out of zircons. Compared to the significantly modified Lu–Hf isotopic compositions, the U–Th–Pb geochronological systematics in the zircons did not change significantly, though there are large variations of U, Th and Pb concentrations between zircons from different ore/rock samples (Table 4).

7. Conclusion The quartz-stibnite ores in the Banxi antimony deposit have the same zircon

U–Pb ages as their host rocks, indicating contribution of ore material from the Banxi Group. However, the highly radiogenic Hf isotopes in the hydrothermally altered wall rocks suggest a deeper fluid source from the Lengjiaxi Group and the crystalline basement beneath. The deep-sourced, high radiogenic Hf fluid mixed with circulating near-surface meteoric component-dominated fluid, causing Sb precipitation. The changing of Lu–Hf systematics in the co-precipitated zircons can be ascribed to lattice breakdown in old zircons during the fluid mixing process and the external input of highly radiogenic Hf. Zircon records a detailed fluid evolutionary process at the Banxi Sb deposit. Multiple approaches such as CL, BSE, U–Pb, Lu–Hf, major and trace element analysis for zircons from variable ore/rock types provide a feasible way to reveal the ore genesis in complex hydrothermal systems.

Acknowledgments This work was co-financed by the National Natural Science Foundation of China (Grant No. 41502067). Two anonymous reviewers are appreciated for their useful comments and suggestions that significantly improved the manuscript. We also thank Guest Editor Prof. Xiaoyong Yang and Editor-in-Chief Prof. Franco Pirajno for their editorial handling of the manuscript.

References Amelin, Y., Lee, D., Halliday, A.N., 2000. Early-middle Archaean crustal evolution deduced from Lu–Hf and U–Pb isotopic studies of single zircon grains. Geochimica et Cosmochimica Acta, 64, 4205–4225.

Andersen, T., 2002. Correction of common lead in U–Pb analyses that do not report 204Pb.

Chemical Geology 192, 59–79.

Belousova, E.A., Kostitsyn, Y.A., Griffin, W.L., Begg, G.C., O’Reilly, S.Y., Pearson, N.J., 2010. The growth of the continental crust: constraints from zircon Hf-isotope data. Lithos 119, 457–466. Bouvier A., Vervoort J.D., Patchett P.J., 2008. The Lu–Hf and Sm–Nd isotopic composition of CHUR: constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets. Earth and Planetary Science Letters 273, 48–57. Chen, J., Yang, R.D., Du, L.J., Zheng, L.L., Gao, J.B., Lai, C.K., Wei, H.R., Yuan, M.G., 2018. Mineralogy, geochemistry and fluid inclusions of the Qinglong Sb-(Au) deposit, Youjiang basin (Guizhou, SW China). Ore Geology Reviews 92, 1–18. Chen, L., Liu, Y., Hu, Z., Gao, S., Zong, K.Q., Chen, H.H., 2011. Accurate determinations of fifty-four major and trace elements in carbonate by LA-ICP-MS using normalization strategy of bulk components as 100%. Chemical Geology 284, 283–295. Chen, X.Y., Yin, P., Kuang, W.L., Dai, D.Q., Zi, F., 2012. Advance research of Au multi-metal metallogenic belt in Xuefeng Region, western Hunan Province. Geological Science and Technology Information 31, 82–88 (in Chinese with English Abstract). Cherniak, D. J. Hanchar, J. M., Watson, E. B., 1997. Diffusion of tetravalent cations in zircon. Contributions to Mineralogy and Petrology 127, 383–390. Cherniak, D.J., Watson, E.B., 2001. Pb diffusion in zircon. Chemical Geology 172, 5–24.

Chu, N. C., Taylor, R.N., Chavagnac, V., Nesbitt, R.W., Boella, R.M., Milton, J.A., German, C.R., Bayon, G., Burton, K., 2002. Hf isotope ratio analysis using multi-collector inductively coupled plasma mass spectrometry: an evaluation of isobaric interference corrections. Journal of Analytical Atomic Spectrometry 17, 1567–1574. Chu, Y., Faure, M., Lin, W., Wang, Q.C., 2012. Early Mesozoic tectonics of the South China block: Insights from the Xuefengshan intracontinental orogeny. Journal of Asian Earth Sciences 61, 199-220. De Biévre, P., Taylor, P.D.P., 1993. Table of the isotopic compositions of the elements. International Journal of Mass Spectrometry & Ion Processes 123, 149–166. Deng, T., Xu, D., Chi, G., Wang, Z., Jiao, Q., Ning, J., Dong, G., Zou, F., 2017. Geology, geochronology, geochemistry and ore genesis of the Wangu gold deposit in northeastern Hunan Province, Jiangnan Orogen, South China. Ore Geology Reviews 88, 619–637. Dong, G.J., Xu, D.R., Wang, L., Chen, G.H., He, Z.L., Fu, G.G., Wu, J., Wang, Z.L., 2008. Determination of mineralizing ages in gold ore deposits in the eastern Hunan Province, South China and isotopic tracking on ore-forming fluids-Re-discussing gold ore deposit type. Geotectonica et Metallogenia 32, 482-491 (in Chinese with English abstract). Duchene, S., Blichert-Toft, J., Luais, B., Telouk, P., Lardeaux, J.M., Albarede, F., 1997. The Lu–Hf dating of garnets and the ages of the Alpine high-pressure metamorphism. Nature 387, 586–589. Fan, D.L., Zhang, T., Ye, J., 2004. The Xikuangshan Sb deposit hosted by the Upper Devonian black shale series, Hunan, China. Ore Geology Reviews 24, 121–133.

Fu, B., Mernagh, T.P., Kita, N.T., Kemp, A.I.S., Valley, J.W., 2009. Distinguishing magmatic zircon from hydrothermal zircon: a case study from the Gidginbung high sulphidation Au–Ag–(Cu) deposit, SE Australia. Chem. Geol. 259, 131–142. Fu, S.L., Hu, R.Z., Chen, Y.W., Luo, J.C., 2016. Chronology of the large Longshan Au-Sb deposit in central Hunan Province: Constraints from pyrite Re-Os and zircon U-Th/He isotopic dating. Acta Petrologica Sinica 32, 3507–3517. Ge, X., Shen, C., Selby, D., Deng, D., Mei, L., 2016. Apatite fission-track and Re-Os geochronology of the Xuefeng uplift, China: Temporal implications for dry gas associated hydrocarbon systems. Geology 44, 491–494. Gerdes, A., Zeh, A., 2009. Zircon formation vs. zircon alteration—New insights from combined U−Pb and Lu−Hf in situ LA-ICP-MS analyses, and consequences for the interpretation of Archean zircon from the Central Zone of the Limpopo Belt. Chemical Geology 261, 230−243. Girei, M.B., Li, H., Algeo, T.J., Bonin, B., Ogunleye, P.O., Bute, S.I., Ahmed, H.A., 2019. Petrogenesis of A-type granites associated with Sn–Nb–Zn mineralization in Ririwai complex, north-Central Nigeria: Constraints from whole-rock Sm–Nd and zircon Lu–Hf isotope systematics. Lithos 340–341, 49–70. 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, 237–269. Gu, X.X., Schulz, O., Vavtar, F., Liu, J.M., Zheng, M.H., Fu, S.H., 2007. Rare earth element geochemistry of the Woxi W–Sb–Au deposit, Hunan Province, South China. Ore Geology Reviews 31, 319–336. Gu, X.X., Zhang, Y.M., Schulz, O., Vavtar, F., Liu, J.M., Zheng, M.H., Zheng, L.,

2012. The Woxi W–Sb–Au deposit in Hunan, South China: An example of Late Proterozoic sedimentary exhalative (SEDEX) mineralization. Journal of Asian Earth Sciences 57, 54–75. Han, F.B., Chang, L., Cai, M.H., Liu, S.Y., Zhang, S.Q., Chen, Y., 2010. Ore-forming epoch of gold deposits in northeastern Hunan. Mineral Deposits 29, 564-571 (in Chinese with English abstract). Horie, K., Hidaka, H., Gauthier-Lafaye, F., 2008. Elemental distribution in apatite, titanite and zircon during hydrothermal alteration: Durability of immobilization mineral phases for actinides. Physics and Chemistry of the Earth, Parts A/B/C 33, 962–968. Hoskin, P.W.O., 2005. Trace-element composition of hydrothermal zircon and the alteration of Hadean zircon from the Jack Hills, Australia. Geochim. Cosmochim. Acta 69, 637–648. Hu, R.Z., Zhou, M.F., 2012. Multiple Mesozoic mineralization events in South China—an introduction to the thematic issue. Mineralium Deposita 47, 579–588. Hu, R.Z., Su, W.C., Bi, X.W., Tu, G.Z., Hofstra, A.H., 2002. Geology and geochemistry of Carlin-type gold deposits in China. Mineralium Deposita 37, 378–392. Hu, Z.C., Gao, S., Liu, Y.S., Hu, S.H., Chen, H. H., and Yuan, H.L., 2008. Signal enhancement in laser ablation ICP-MS by addition of nitrogen in the central channel gas: Journal of Analytical Atomic Spectrometry 23, 1093–1101. Hu, Z.C., Liu, Y.S., Gao, S., Liu, W.G., Zhang, W., Tong, X.R., Lin, L., Zong, K.Q., Li, M., Chen, H.H., Zhou, L., Yang, L., 2012. 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, 1391–1399. Hu, R.Z., Fu, S.L., Xiao, J.F., 2016. Major scientific problems on low-temperature metallogenesis of South China. Acta Petrologica Sinica 32, 3239–3251. Huang, C., Fan, G., Jiang, G., Luo, L., Xu, Z., 2012. Structural ore-controlling characteristics and electron spin resonance dating of the Yanlinsi gold deposit in northeastern Hunan Province. Geotectonica et Metallogenia 36, 76-84 (in Chinese with English abstract). Jackson, S.E., Pearson, N.J., Griffin, W.L., Belousova, E.A., 2004. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pb zircon geochronology. Chemical Geology, 211, 47–69. Jia, S., Wang, E., Fu, J., Wang, X., Li, W., 2019. Geology, fluid inclusions and isotope geochemistry of the Herenping gold deposit in the southern margin of the Yangtze Craton, China: A sedimenthosted reduced intrusion-related gold deposit? Ore Geology Reviews 107, 926–943. Jiang, W.C., Li, H., Wu, J.H., Zhou, Z.K., Kong, H., Cao, J.Y., 2018. A newly found biotite syenogranite in the Huangshaping polymetallic deposit, South China: Insights into Cu mineralization. Journal of Earth Science 29(3), 537–555. Jiang, W.C., Li, H., Mathur, R., Wu, J.H., 2019. Genesis of the giant Shizhuyuan W–Sn–Mo–Bi–Pb–Zn polymetallic deposit, South China: Constraints from zircon geochronology and geochemistry in skarns. Ore Geology Reviews, https://doi.org/10.1016/j.oregeorev. 2019.102980. Kemp, A. I. S., Hawkesworth, C. J., Foster, G. L., Paterson, B. A., Woodhead, J. D., Hergt, J. M., Gray, C. M., Whitehouse, M. J., 2007. Magmatic and crustal differentiation history of granitic rocks from Hf-O isotopes in zircon. Science 315, 980–983.

Kinny, P.D., Maas, R., 2003. Lu–Hf and Sm–Nd isotope systems in zircon. In: Hanchar, J.M., Hoskin, P.W.O. (Eds.), Zircon, Reviews in Mineralogy & Geochemistry. Mineralogical Society of America, vol. 53, pp. 327–341. Kozlik, M., Raith, J.G., Gerdes, A., 2016. U–Pb, Lu–Hf and trace element characteristics of zircon from the Felbertal scheelite deposit (Austria): New constraints on timing and source of W mineralization. Chemical Geology 421, 112–126. Lenting, C., Geisler, T., Gerdes, A., Kooijman, E., Scherer, E.E., Zeh, A., 2010. The behavior of the Hf isotope system in radiation-damaged zircon during experimental hydrothermal alteration. American Mineralogist 95, 1343–1348. Li, W., Xie, G.Q., Zhang, Z.Y., Zhang, X.K., 2016. Constraint on the genesis of Gutaishan gold deposit: Evidence from fluid inclusion and C-H-O isotopes. Acta Petrologica Sinica 32, 3489–3506. Li, H., Watanabe, K., Yonezu, K., 2014. Zircon morphology, geochronology and trace element geochemistry of the granites from the Huangshaping polymetallic deposit, South China: Implications for the magmatic evolution and mineralization processes. Ore Geology Reviews 60, 14–35. Li, H., Sun, H.S., Wu, J.H., Evans, N.J., Xi, X.S., Peng, N.L., Cao, J.Y., Gabo-Ratio, J.A.S., 2017. Re–Os and U–Pb geochronology of the Shazigou Mo polymetallic ore field, Inner Mongolia: Implications for Permian–Triassic mineralization at the northern margin of the North China Craton, Ore Geology Reviews 83, 287–299. Li, H., Wu, Q.H., Evans, N.J., Zhou, Z.K., Kong, H., Xi, X.S., Lin, Z.W., 2018a. Geochemistry and geochronology of the Banxi Sb deposit: Implications for fluid origin and the evolution of Sb mineralization in central-western Hunan, South

China. Gondwana Research 55, 112–134. Li, H., Sun, H.S., Algeo, T.J., Wu, J.H., Cao, J.Y., Wu, Q.H., 2018b. Mesozoic multi-stage W–Sn polymetallic mineralization in the Nanling Range, South China: An example from the Dengfuxian–Xitian ore field. Geological Journal, https://doi.org/10.1002/gj.3369. Li, H., Wu, J.H., Evans, N.J., Jiang, W.C., Zhou, Z.K., 2018c. Zircon geochronology and geochemistry of the Xianghualing A-type granitic rocks: Insights into multi-stage Sn-polymetallic mineralization in South China. Lithos 312–313, 1–20. Li, H., Li, J.W., Algeo, T.J., Wu, J.H., Cisse, M., 2018d. Zircon indicators of fluid sources and ore genesis in a multi-stage hydrothermal system: The Dongping Au deposit in North China. Lithos 314–315, 463–478. Li, H., Myint, A.Z., Yonezu, K., Watanabe, K., Algeo, T.J., Wu, J.H., 2018e. Geochemistry and U–Pb geochronology of the Wagone and Hermyingyi A-type granites, southern Myanmar: Implications for tectonic setting, magma evolution and Sn–W mineralization. Ore Geology Reviews 95, 575–592 Li, H., Cao, J., Algeo, T.J., Jiang, W., Liu, B., Wu, Q., 2019a. Zircons reveal multi-stage genesis of the Xiangdong (Dengfuxian) tungsten deposit, South China. Ore Geology Reviews, https://doi.org/10.1016/j.oregeorev.2019.102979. Li, H., Zhou, Z.K., Algeo, T.J., Wu J.H., Jiang, W.C., 2019b. Geochronology and geochemistry of tuffaceous rocks from the Banxi Group: Implications for Neoproterozoic tectonic evolution of the southeastern Yangtze Block, South China. Journal of Asian Earth Sciences 177, 152–176. Li, H.Q., Wang, D.H., Chen, F.W., Mei, Y.P., Cai, H., 2008. Study on Chronology of the Chanziping and Daping gold deposit in Xuefeng Mountains, Hunan Province.

Acta Geologica Sinica 82, 900-905 (in Chinese with English abstract). Lichtervelde, M.V., Frank, M., Richard, W., 2009. Magmatic vs. hydrothermal origins for zircon associated with tantalum mineralization in the Tanco pegmatite, Manitoba, Canada. American Mineralogist 94, 439-450. Liang, Y., Wang, G.G., Liu, S.Y., Sun, Y.Z., Huang, Y.G., Hoshino, K., 2014. A study on the mineralization of the Woxi Au–Sb–W deposit, western Hunan, China. Resource Geology 65, 27–38. Liu, Y.S., Hu, Z.C., Gao, S., Günther, D., Xu, J., Gao, C.G., Chen, H.H., 2008. In situ analysis of major and trace elements of anhydrous minerals by LA-ICP-MS without applying an internal standard. Chemical Geology 257, 34–43. Liu, Y.S., Hu, Z.C., Zong, K.Q., Gao, C.G., Gao, S., Xu, J., Chen, H.H., 2010. Reappraisement and refinement of zircon U-Pb isotope and trace element analyses by LA-ICP-MS. Chinese Science Bulletin 55, 1535–1546. Liu, S.Y., Bao, Z.X., Bao, J.M., 2013. Gold deposit features and metallogenic regularity of Precambrian in Hunan province, China. Geology and Mineral Resources of South China 29, 37–45 (in Chinese with English abstract). Liu, X., Wu, Y., Gao, S., Wang, H., Zheng, J., Hu, Z., Zhou, L., Yang, S., 2014. Record of multiple stage channelized fluid and melt activities in deeply subducted slab from zircon U–Pb age and Hf–O isotope compositions. Geochimica et Cosmochimica Acta 144, 1–24. Luais, B., Veslud, C.L.C.D., Géraud, Y., Gauthier-Lafaye, F., 2009. Comparative behavior of Sr, Nd and Hf isotopic systems during fluid-related deformation at middle crust levels. Geochimica et Cosmochimica Acta 73, 2961–2977. Ludwig, K.R., 2003. User’s Manual for Isoplot 3.00: A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronology Center Special Publication, No. 4, pp.

70. Luo, X.L., 1989. On the epoch of the formation of Precambrian gold deposits in Hunan Province. Journal of Guilin College of Geology 9, 25-34 (In Chinese with English abstract). Meng, Q.X., Zhang, J., Geng, J.Z., Zhang, C.L., Huang, W.C., 2013. Zircon U-Pb age and Hf isotope compositions of Lengjiaxi and Baxi Groups in middle Hunan Province: implications for the Neoproterozoic tectonic evolution in South China. Geology in China 40, 191–216 (in Chinese with English abstract). Nardia, L.V.S., Formoso, M.L.L., Müller, I.F., Fontana, E., Jarvis, K., Lamarã, C., 2013. Zircon/rock partition coefficients of REEs, Y, Th, U, Nb, and Ta in granitic rocks: Uses for provenance and mineral exploration purposes. Chemical Geology 335, 1–7. Peng, J.T., Dai, T.G., 1998. Ob the mineralization epoch of the Xuefeng gold metallogenic province. Geology and Prospecting 34, 37–41 (in Chinese with English abstract). Peng, J.T., Dai, T.G., 1999. Geochemical studies of ore-forming fluids in gold deposits of southwestern Hunan. Mineral deposits 18, 73–82. Peng, B., Frei, R., 2004. Nd–Sr–Pb isotopic constraints on metal and fluid sources in W–Sb–Au mineralization at Woxi and Liaojiaping (Western Hunan, China). Mineralium Deposita 39, 313–327. Peng, J.T., Hu, R.Z., Zhao, J.H., Fu, Y.Z., Lin, Y.X., 2003a. Scheelite Sm-Nd dating and quartz Ar-Ar dating for Woxi Au-Sb-W deposit, western Hunan. Chinese Science Bulletin 48, 2640–2646. Peng, J.T., Hu, R.Z., Burnard, P.G., 2003b. Samarium–neodymium isotope systematics of hydrothermal calcites from the Xikuangshan antimony deposit

(Hunan, China): the potential of calcite as a geochronometer. Chemical Geology 200, 129– 136. Peng, J.T., Zhang, D.L., Hu, R.Z., Wu, M.J., Lin, Y.X., 2008. Sm-Nd and Sr isotope geochemistry of hydrothermal scheelite from the Zhazixi W-Sb deposit, western Hunan. Acta Geologica Sinica 82, 1514–1521 (in Chinese with English abstract). Pettke,

T.,

Audetat,

A.,

Schaltegger,

U.,

Heinrich,

C.A.,

2005.

Magmatic-to-hydrothermal crystallization in the W–Sn mineralized Mole Granite (NSW, Australia)—Part II: evolving zircon and thorite trace element chemistry. Chem. Geol. 220, 191–213. Pidgeon, R.T., 2014. Zircon radiation damage ages. Chemical Geology, 367, 13–22. Scherer, E.E., Cameron, K.L., Johnson, C.M., Beard, B.L., Barovich, K.M., Collerson, K.D., 1997. Lu–Hf geochronology applied to dating Cenozoic events affecting lower crustal xenoliths from Kilbourne Hole, New Mexico. Chemical Geology 142, 63–78. Sheng, Y.M., Zheng, Y.F., Chen, R.X., Li, Q., Dai, M., 2012. Fluid action on zircon growth and recrystallization during quartz veining within UHP eclogite: Insights from U–Pb ages, O–Hf isotopes and trace elements. Lithos 136–139, 126–144. Söderlund, U., Patchett, J.P., Vervoort, J.D., Isachsen, C.E., 2004. The Lu-176 decay constant determined by Lu–Hf and U–Pb isotope systematics of Precambrian mafic intrusions. Earth and Planetary Science Letters 219, 311–324. Su, W.C., Heinrich, C.A., Pettke, T., Zhang, X.C., Hu, R.Z., Xia, B., 2009. Sediment-hosted gold deposits in Guizhou, China: products of wall-rock sulfidation by deep crustal fluids. Economic Geology 104, 73–93. Su, J.B., Dong, S.W., Zhang, Y.Q., Li, Y., Chen, X.H., Ma, L.C., Chen, J.S., 2017. Orogeny processes of the western Jiangnan Orogen, South China：Insights from

Neoproterozoic igneous rocks and a deep seismic profile. Journal of Geodynamics 103, 42–56. Sun, H.S., Li, H., Evans, N.J., Yang, H., Wu, P., 2017. Volcanism, mineralization and metamorphism at the Xitieshan Pb–Zn deposit, NW China: Insights from zircon geochronology and geochemistry. Ore Geology Reviews 88, 289–303. Taylor, S.R., McLennan, S.M., 1985. The Continental Crust: Its Composition and Evolution. Oxford Press, Blackwell, pp. 1–312. Tu, G.C., 2002. Two unique mineralization areas in Southwest China. Bulletin of mineralogy, Petrology and Geochemistry 21, 1–2 (in Chinese with English abstract). Valley, P.M., Fisher, C.M., Hanchar, J.M., Lam, R., Tubrett, M., 2010. Hafnium isotopes in zircon: A tracer of fluid-rock interaction during magnetite–apatite (“Kiruna-type”) mineralization. Chemical Geology 275, 208–220. Veksler, I.V., Dorfman, A.M., Kamenetsky, M., Dulski, P., Dingwell, D.B., 2005. Partitioning of lanthanides and Y between immiscible silicate and fluoride melts, fluorite and cryolite and the origin of the lanthanide tetrad effect in igneous rocks. Geochimica et Cosmochimica Acta 69, 2847–2860. Vervoort, J.D., Blichert-Toft, J., 1999. Evolution of the depleted mantle: Hf isotopeevidence from juvenile rocks through time. Geochimica et Cosmochimica Acta 63, 533–556. Wan, J., 1986. Geochemical studies of the Xi’an tungsten ore deposit, west Hunan, China. Geochemica 2, 183-192 (in Chinese with English abstract). Wang, H.J., Zhou, J., Xu, Q.S., Liu, C.X., Zhu, M.X., 2003. Very low-grade metamorphism of the Meso-Neoproterozoic and the Lower Paleozoic along the profile from Huangtuthan to Xianxi in the central-northern part of Hunan

Province, China. Science in China Series D-Earth Sciences 46, 672–682. Wang, X.L., Zhou, J.C., Griffin, W.L., Wang, R.C., Qiu, J.S., O’Reilly, S.Y., Xu, S.S., Liu, X.M., Zhang, G.L., 2007. Detrital zircon geochronology of Precambrian basement sequences in the Jiangnan orogen: Dating the assembly of the Yangtze and Cathaysia Blocks. Precambrain Res 159, 117–131. Wang, X.Z., Liang, H.Y., Shan, Q., Cheng, J.P., Xia, P., 1999. Metallogenic age of the Jinshan gold deposit and Caledonian gold mineralization in South China. Geological Review 45, 19-25 (in Chinese with English abstract). Wang, W., Wang, F., Chen, F., Zhu, X., Xiao, P., Siebel, W., 2010. Detrital Zircon Ages and Hf-Nd Isotopic Composition of Neoproterozoic Sedimentary Rocks in the Yangtze Block: Constraints on the Deposition Age and Provenance. Journal of Geology 118, 79–94. Wang, P.M., Yu, J.H., Sun, T., Ling, H.F., Chen, P.R., Zhao, K.D., Chen, W.F., Liu, Q., 2012. Geochemistry and detrital zircon geochronology of Neoproterozoic sedimentary rocks in eastern Hunan Province and their tectonic significance. Acta Petrologica Sinica 28, 3841–3857. Wang, J. Q.; Shu, L. S.; Santosh, M., 2016. Petrogenesis and tectonic evolution of Lianyunshan complex, South China: Insights on Neoproterozoic and late Mesozoic tectonic evolution of the central Jiangnan Orogen. Gondwana Research 39, 114-130. Wiedenbeck, M., Hanchar, J.M., Peck, W.H., Sylvester, P., Valley, J., Whitehouse, M., Kronz, A., Morishita, Y., Nasdala, L., Fiebig, J., Franchi, I., Girard, J.P., Greenwood, R.C., Hinton, R., Kita, N., Mason, P.R.D., Norman, M., Ogasawara, M., Piccoli, P.M., Rhede, D., Satoh, H., Schulz-Dobrick, B., Skar, O., Spicuzza, M.J., Terada, K., Tindle, A., Togashi, S., Vennemann, T., Xie, Q., Zheng, Y.F.,

2004. Further characterisation of the 91500 zircon crystal. Geostandards and Geoanalytical Research 28, 9–39. Woodhead, J., Hergta, J., Shelley, M., Eggins, S., Kemp, R., 2004. Zircon Hf-isotope analysis with an excimer laser, depth profiling, ablation of complex geometries, and concomitant age estimation. Chemical Geology 209, 121–135. Wu, J.H., Li, H., Algeo, T.J. Jiang, W.C., Zhou, Z.K., 2018. Genesis of the Xianghualing Sn–Pb–Zn deposit, South China: A multi-method zircon study. Ore Geology Reviews 102, 220–239. Wu, Y.B., Zheng, Y.F., Zhao, Z.F., Gong, B., Liu, X.M., Wu, F.Y., 2006. U-Pb, Hf and O isotope evidence for two episodes of fluid-assisted zircon growth in marble-hosted eclogites from the Dabie orogen. Geochimica et Cosmochimica Acta, 70, 3743–3761. Wu, Y.B., Zheng, Y.F., Zhang, S.B., Zhao, Z.F., Wu, F.Y. & Liu, X.M., 2007. Zircon U-Pb ages and Hf isotope compositions of migmatite from the North Dabie terrane in China: constraints on partial melting. Journal of Metamorphic Geology, 25, 991–1009. Xiong, Q., Zheng, J., Griffin, W.L., O'Reilly, S.Y., Pearson, N.J., 2012. Decoupling of U–Pb and Lu–Hf isotopes and trace elements in zircon from the UHP North Qaidam orogen, NE Tibet (China): Tracing the deep subduction of continental blocks. Lithos 155, 125–145. Yang, R.Y., Ma, D.S., Bao, Z.Y., Pan, J.Y., Cao, S.L., Xia, F., 2006a. Geothermal and fluid flowing simulation of ore-forming antimony deposits in Xikuangshan. Science in China: Series D Earth Sciences 49, 862–871. Yang, D.S., Shimizu, M., Shimazaki, H., Li, X.H., Xie, Q.L., 2006b. Sulfur Isotope Geochemistry of the Supergiant Xikuangshan Sb Deposit, Central Hunan, China:

Constraints on Sources of Ore Constituents. Resource Geology 56, 385–396. Zeh, A., Gerdes, A., 2014. HFSE (High Field Strength Elements)-transport and U-Pb–Hf isotope homogenization mediated by Ca-bearing aqueous fluids at 2.04 Ga: constraints from zircon, monazite, and garnet of the Venetia Klippe, Limpopo Belt. South Africa. Geochimica et Cosmochimica Acta, 138, 81–100. Zeh, A., Gerdes, A., Will, T.M., Frimmel, H.E., 2010. Hafnium isotope homogenization during metamorphic zircon growth in amphibolite-facies rocks: examples from the Shackleton Range (Antarctica). Geochimica et Cosmochimica Acta, 74, 4740–4758. Zhang, Y., Wang, Y., 2016. Early Neoproterozoic (similar to 840 Ma) arc magmatism: Geochronological and geochemical constraints on the metabasites in the Central Jiangnan Orogen. Precambrian Research 275, 1-17. Zhang, Q.R., Li, X.H., Feng, L.J., Huang, J., Song, B., 2008a. A new age constraint on the onset of the Neoproterozoic glaciations in the Yangtze Platform, South China. Journal of Geology 116, 423–429. Zhang, S.H., Jiang, G.Q., Dong, J., Han, Y.G., Wu, H.C., 2008b. New SHRIMP U-Pb age from the Wuqiangxi Formation of Banxi Group: Implications for rifting and stratigraphic erosion associated with the early Cryogenian (Sturtian) glaciation in South China. Science in China Series D: Earth Sciences 51, 1537–1544. Zhang, Y.Z., Wang, Y.J., Fan, W.M., Zhang, A.M., Ma, L.Y., 2012. Geochronological and geochemical constraints on the metasomatised source for the Neoproterozoic (∼825 Ma) high-mg volcanic rocks from the Cangshuipu area (Hunan Province) along the Jiangnan domain and their tectonic implications. Precambrian Research 220– 221, 139–157. Zhang. D.L., Huang, D.Z., Zhang, H.F., Wang, G.Q., Du, G.F., 2016. Chronological

framework of basement beneath the Xiangzhong Basin: Evidence by U-Pb ages of detrital zircons from Xikuangshan. Acta Petrologica Sinica 32, 3456–3468. Zhang, L., Yang, L.Q., Groves, D.I., Liu, Y., Sun, S.C., Qi, P., Wu, S.G., Peng, J.S., 2018. Geological and isotopic constraints on ore genesis, Huangjindong gold deposit, Jiangnan Orogen, southern China. Ore Geology Reviews 99, 264–281. Zhang, Z., Xie, G., Mao, J., Liu, W., Olin, P., Li, W., 2019. Sm-Nd Dating and In-Situ LA-ICP-MS Trace Element Analyses of Scheelite from the Longshan Sb-Au Deposit, Xiangzhong Metallogenic Province, South China. Minerals, doi:10.3390/min9020087. Zhao, Z.H., Tu, G.C., 2003. Supper Ore Deposits in China (II). Beijing: Science Press, p: 1–631. Zhao, G.C., Cawood, P.A., 2012. Precambrian geology of China. Precambrian Research 222–223, 13– 54. Zhao, Y.J., Wu, Y.B., Liu, X.C., Gao, S., Wang, H., Zheng, J.P., Yang, S.H., 2016. Distinct zircon U–Pb and O–Hf–Nd–Sr isotopic behaviour during fluid flow in UHP metamorphic rocks: evidence from metamorphic veins and their host eclogite in the Sulu Orogen, China. Journal of Metamorphic Geology 34, 343–362. Zheng, Y.F., Wu, Y.B., Zhao, Z.F., Zhang, S.B., Xu, P. & Wu, F.Y., 2005. Metamorphic effect on zircon Lu–Hf and U-Pb isotope systems in ultrahigh-pressure eclogite-facies metagranite and metabasite. Earth and Planetary Science Letters, 240, 378–400. Zheng, Y.-F., Zhang, S.-B., Zhao, Z.-F., Wu, Y.-B., Li, X., Li, Z., Wu, F.-Y., 2007. Contrasting zircon Hf and O isotopes in the two episodes of Neoproterozoic granitoids in South China: implications for growth and reworking of continental

crust. Lithos 96, 127–150. Zheng, Y.F., Wu, R.X., Wu, Y.B., Zhang, S.B., Yuan, H.L., Wu, F.Y., 2008. Rift melting

of

juvenile

arc-derived

crust:

geochemical

evidence

from

Neoproterozoic volcanic and granitic rocks in the Jiangnan Orogen south China. Precambrian Research 163, 351–383. Zhu, Y.N., Peng, J.T., 2015. Infrared microthermometric and noble gas isotope study of fluid inclusions in ore minerals at the Woxi orogenic Au–Sb–W deposit, western Hunan, South China. Ore Geology Reviews 65, 55–69.

Figure captions Figure 1. Simplified geological map of South China and adjacent regions showing the distribution of low-temperature ore provinces (after Hu and Zhou, 2012; Hu et al., 2016). The blue box is the area expanded in Figure 2.　 Figure 2. Geological map of central-western Hunan region showing the distribution of Sb–Au deposits (after Liu et al., 2013; Zhu and Peng, 2015). Figure 3. Geological map (a) and cross section (b) of the Banxi antimony deposit. The names of mineralized veins are given in the small circles (e.g., 2-1 or R10) in (a) and (b). Line A-A’ in (a) is the cross-section given in (b). Figure 4. Field occurrences of wall rocks, ore bodies and alteration zones at the Banxi Sb deposit. (a) grey–green meta-sedimentary tuff from the first sub-section of the Wuqiangxi Formation; (b) tuffaceous slate from the second sub-section of the Wuqiangxi Formation; (c) banded slate from the third sub-section of the Wuqiangxi Formation; (d) quartz vein containing few sulfides in the first stage mineralization; (e)

quartz vein intergrowth with stibnite in the second quartz-sulfide stage; (f) stibnite ore in the third stibnite-sulfide stage; (g) calcite vein containing chlorite in the fourth carbonate stage; (h) silicification close to the Sb ore body; (i) pyritization occurring as sulfide veinlets in the wall rocks. Qz: quartz; Py: pyrite; Sti: stibnite; Chl: chlorite; Cal: calcite. Figure 5. Hand specimen images (a-c) and macrographs (d-f) of analyzed antimony ores and hydrothermally altered wall rock from the Banxi Sb deposit. (a), (d): sample BX4-5; (b), (e): sample BX4-6; (c), (f): sample BX7-3. Qz: quartz; Sti: stibnite; Ars: arsenopyrite. Figure 6. (a) Reflected light, (b) transmitted light and (c) BSE photomicrographs of zircons from the Banxi antimony deposit. Zrn: zircons; Bt: biotite; Px: pyroxene; Qtx: quartz; St: stibnite. Figure 7. CL-images of analyzed zircons from samples BX4-5 (a), BX4-6 (b) and BX7-3 (c), showing U-Pb dating and Hf measuring spots. Figure 8. U–Pb concordant ages of different zircon groups in samples (a-c) BX4-5, (d-f) BX4-6 and (g-h) BX7-3 from the Banxi antimony deposit. Figure 9. Plots of (a) SiO2 + ZrO2 vs. F, (b) ZrO2 vs. HfO2, (c) ZrO2 vs. UO2, (d) ZrO2 vs. ThO2, (e) UO2 vs. ThO2, (f) SiO2 + ZrO2 vs. Y2O3 + HREE2O3 + P2O5, (g) Y2O3 + HREE2O3 vs. P2O5, and (h) SiO2 + ZrO2 vs. Zr/Hf for the zircons from the Banxi antimony deposit. HREE2O3 = Er2O3 + Dy2O3 + Lu2O3. Error bars are within the symbol. Figure 10. Plots of (a) Hf vs. Ti, (b) Hf vs, Y, (c) Hf vs. U, and (d) Hf vs. Th/U for the zircons from the Banxi antimony deposit. Error bars are within the symbol.

Figure 11. Chondrite-normalized REE patterns for samples (a) BX4-5, (b) BX4-6, and (c) BX7-3 from the Banxi antimony deposit. Normalized values for chondrite are from Taylor and McLennan (1985). Numbers identify patterns for the grains in Fig. 6. Figure 12. Plots of (a) 176Lu/177Hf vs. 176Hf/177Hf and (b) 176Yb/177Hf vs. εHf(t) for the different group zircons of samples BX4-5, BX4-6, and BX7-3 from the Banxi antimony deposit. Group 1: Neoproterozoic zircons; Group 2: Paleoproterozoic (samples BX4-5 and BX4-6) + Mesoproterozoic (sample BX7-3) zircons. Error bars are within the symbol. Figure 13. Plots of (a) ΣREE vs. LREE, (b) ΣREE vs. Eu/Eu*, (c) (Sm/La)N vs. Ce/Ce*, (d) La vs. (Sm/La)N, (e) Y vs. Nb/Ta and (f) Y vs. Hf/Y for the zircons from the Banxi antimony deposit. (c) and (d) after Hoskin (2005). Errors are within the symbol. Figure 14. Plots of age vs. (a) 176Hf/177Hf, with the trend towards more hydrothermal signatures noted, (b) 176Lu/177Hf, (c) 176Yb/177Hf and (d) TDM1 for the zircons from the Banxi antimony deposit and the Banxi Group. Data of the unaltered zircons from the Banxi Group clastic rocks are from Wang et al. (2010), Wang et al. (2012) and Meng et al. (2013). Figure 15. A fluid mixing model illustrating the genesis of the Banxi antimony deposit in the co-precipitated zircons. (a) Magma intrusion provided the heat to circulate crystalline basement-derived fluids. (b) Breakdown of garnets during retrograde metamorphism led to highly radiogenic Hf in the circulated fluids. (c) Initial ore-forming fluids penetrated the Lengjiaxi Group along deep faults and encorporated some detrital zircons. (d) Highly radiogenic Hf fluids migrated into the shallower Banxi Group and mixed with meteoric ore-bearing fluids, resulting in metal

precipitation. Layers (a, b, c and d) have been confirmed by recent geophysical exploration and drilling activity carried out by the mine. Table 1. Summary of the Sb–Au deposits in the central-western Hunan region. N

Deposit

o

name

Wallrocks

Reso

Mineral assemblages

Mineralization age

Referen

urces

ces

. 1

Huangji

Neoproterozoi

80 t

native gold + arsenopyrite +

462 ± 18 Ma and 152 ± 13 Ma

Dong et

ndong

c Lengjiaxi

Au

pyrite + pyrrhotite + chalcopyrite

(quartz Rb-Sr isochron age)

al.,

Group slates

+ galena + sphalerite + quartz

2008; Han et al., 2010; Zhang et al., 2018

2

3

Wangu

Yanlinsi

Neoproterozoi

85 t

native gold + arsenopyrite +

425 ± 33 Ma (quartz Rb-Sr

Han et

c Lengjiaxi

Au

pyrite + scheelite + sphalerite +

isochron age), 142-130 Ma (zircon

al.,

Group slates

@

chalcopyrite + galena + stibnite +

U-Pb and muscovite Ar/ Ar age)

2010;

6.8

chalcostibite + burnonite + quartz

Deng et

g/t

+ calcite

al., 2017

Neoproterozoi

<20 t

native gold + pyrite +

214 Ma and 177-155 Ma (quartz

Huang

c Lengjiaxi

Au

arsenopyrite + sphalerite + galena

ESR age)

et al.,

Group

+ arsenopyrite + chalcopyrite +

epimetamorphi

quartz + sericite + calcite +

c sandstone,

chlorite

40

39

2012

siltstone and slates 4

Hongyu

Neoproterozoi

<5 t

an

c Lengjiaxi

Au

native gold + pyrite + quartz

Group epimetamorphi c sandstone, siltstone and slates 5

Xichong

Neoproterozoi

<20 t

native gold + ankerite +

c Lengjiaxi

Au,

muscovite + pyrite + arsenopyrite

Group

<0.1

+ scheelite + sphalerite + stibnite

epimetamorphi

Mt

+ galena + quartz

c sandstone,

Sb

siltstone and slates 6

Fuzhuxi

Neoproterozoi

<20 t

native gold + stibnite +

c Banxi Group

Au,

arsenopyrite + chalcopyrite +

epimetamorphi

<1

muscovite + pyrite + scheelite +

544 Ma (galena Pb model age)

Luo, 1989

c sedimentary

Mt

and volcanic

Sb

quartz

rocks 7

Canglan

Neoproterozoi

<5 t

native gold + pyrite + muscovite

445 Ma (pyrite Pb model age)

Luo,

gping

c Banxi Group

Au

+ sericite + quartz

Neoproterozoi

0.25

scheelite + pyrite + stibnite +

402 ± 6 Ma (scheelite Sm-Nd

Peng et

c Banxi Group

Mt

native gold + wolframite +

isochron age), 423-416 Ma (quartz

al.,

low-grade

WO3

arsenopyrite + sphalerite + galena

40

metamorphic

@

+ quartz

clastic rocks

0.2–0

1989

epimetamorphi c sedimentary and volcanic rocks 8

Woxi

Ar- Ar age). 39

2013a

.8%; 1.67 Mt Sb @ 2–6% ; 42 t Au @ 5–10 g/t 9

Huangtu

Neoproterozoi

<5 t

scheelite + native gold + stibnite

dian

c Banxi Group

Au

+ pyrite + tetrahedrite + galena +

epimetamorphi

751 Ma (pyrite Pb model age)

Luo, 1989

quartz

c sedimentary and volcanic rocks 1

Liulinch

Neoproterozoi

<5 t

native gold + pyrite +

412 Ma (K-feldspar K-Ar age),

Luo,

0

a

c Banxi Group

Au

chalcopyrite + galena + sphalerite

585 Ma (pyrite Pb model age)

1989;

epimetamorphi

+ quartz

Wang et

c sedimentary

al.,

and volcanic

1999;

rocks

Jia et al., 2019

1 1

Xi'an

Neoproterozoi

<5 t

scheelite + quartz + calcite +

412 ± 6 Ma (altered slate K-Ar

c Banxi Group

Au,

chalcopyrite + pyrite + native

age)

epimetamorphi

<0.05

gold + galena + sericite + chlorite

c sedimentary

Mt

+ pyrophyllite

and volcanic

WO3

rocks

Wan, 1986

1

Dengshi

Neoproterozoi

2.3 t

2

qiao

c Banxi Group

Au

epimetamorphi

@

c sedimentary

7.9

and volcanic

g/t

native gold + pyrite + quartz

rocks 1

Jingken

Neoproterozoi

1.6 t

Ag-bearing native gold + pyrite +

178-150 Ma (galena Pb model

Luo,

3

gchong

c Banxi Group

Au

pyrrhotite + chalcopyrite +

age)

1989

epimetamorphi

@

arsenopyrite + galena + sphalerite

c sedimentary

8.7

+ scheelite + quartz

and volcanic

g/t

rocks 1

Longsha

Neoproterozoi

3.7

stibnite + native gold + scheelite

210 ± 2 Ma (scheelite Sm-Nd

Zhang et

4

n

c Banxi Group

Mt

+ pyrite + arsenopyrite + galena

isochron age)

al., 2019

slates

ore

+ sphalerite + chalcopyrite +

@

wolframite + jamesonite +

4.5%

chalcostibnite + quartz

Sb and 4.6 g/t Au 1

Hexinqi

Neoproterozoi

<5 t

native gold + scheelite + stibnite

5

ao

c Banxi Group

Au,

+ arsenopyrite + pyrite + quartz

epimetamorphi

<0.05

c sedimentary

Mt

and volcanic

WO3

rocks 1

Lengjia

Neoproterozoi

<5 t

stibnite + native gold +

6

wo

c Banxi Group

Au

arsenopyrite + pyrite + quartz

epimetamorphi c sedimentary and volcanic rocks 1

Longwa

Neoproterozoi

<5 t

native gold + stibnite +

7

ngjiang

c Banxi Group

Au,

arsenopyrite + pyrite + quartz

epimetamorphi

<0.1

c sedimentary

Mt

and volcanic

Sb

rocks 1

Taojinpi

Neoproterozoi

<5 t

native gold + stibnite +

8

ng

c Banxi Group

Au

arsenopyrite + quartz

epimetamorphi c sedimentary

and volcanic rocks 1

Wangjia

Neoproterozoi

<5 t

native gold + stibnite +

9

cun

c Banxi Group

Au,

arsenopyrite + quartz

epimetamorphi

<0.1

c sedimentary

Mt

and volcanic

Sb

rocks 2

Zhazixi

0

Neoproterozoi

<20 t

native gold + stibnite +

c Banxi Group

Au,

arsenopyrite + pyrite + galena +

epimetamorphi

<1

sphalerite + quartz

c sedimentary

Mt

and volcanic

Sb

rocks 2

Xiaosha

Neoproterozoi

<5 t

1

nxiang

c Banxi Group

Au,

epimetamorphi

<0.1

c sedimentary

Mt

and volcanic

Sb

native gold + pyrite + quartz

rocks 2

Tanghu

Neoproterozoi

<5 t

native gold + pyrite +

2

ping

c Banxi Group

Au,

arsenopyrite + stibnite +

epimetamorphi

<0.05

chalcopyrite + tetrahedrite +

c sedimentary

Mt

galena + quartz

and volcanic

WO3

rocks 2

Huayan

Neoproterozoi

<5 t

native gold + pyrite + stibnite +

3

chong

c Banxi Group

Au

quartz

Neoproterozoi

<5 t

native gold + stibnite +

c Banxi Group

Au

arsenopyrite + pyrite +

epimetamorphi c sedimentary and volcanic rocks 2

Mobin

4

epimetamorphi

chalcopyrite + galena + sphalerite

c sedimentary

+ cinnabar + quartz

and volcanic rocks 2 5

Mibei

Neoproterozoi

<5 t

native gold + stibnite +

c Banxi Group

Au

arsenopyrite + pyrite + quartz

epimetamorphi c sedimentary and volcanic rocks

404 Ma (K-feldspar K-Ar age)

Wan, 1986

2

Taojinpi

Neoproterozoi

<5 t

native gold + chalcopyrite

6

ng

c Banxi Group

Au

+bornite + pyrite + chalcopyrite

epimetamorphi

+ limonite + quartz

c sedimentary and volcanic rocks 2

Pingcha

7

Neoproterozoi

<5 t

native gold + pyrite +

436 ± 9 Ma (quartz Rb-Sr isochron

Peng

c Banxi Group

Au,

arsenopyrite + stibnite +

age)

and Dai,

and Sinian

<0.1

sphalerite + galena + quartz

Jiangkou

Mt

Formation

Sb

1998

epimetamorphi c sedimentary and volcanic rocks 2

Xingfen

Neoproterozoi

<5 t

native gold + arsenopyrite +

8

gshan

c Qingbaikou

Au

pyrrhotite + ilmenite +

Group

chalcopyrite + sphalerite + galena

carbonate and

+ pyrite + quartz

clastic rocks 2

Gutai

9

Neoproterozoi

<5 t

native gold + stibnite +

c Banxi Group

Au,

arsenopyrite + pyrite + quartz

epimetamorphi

<0.1

c sedimentary

Mt

and volcanic

Sb

rocks 3

Qingjin

Neoproterozoi

<5 t

native gold + arsenopyrite +

0

zha

c Banxi Group

Au

pyrite + chalcopyrite + limonite +

epimetamorphi

quartz

c sedimentary and volcanic rocks 3

Daping

1

Neoproterozoi

<5 t

native gold + arsenopyrite +

205 ± 6 Ma (quartz Rb-Sr isochron

Li et al.,

c Furongxi

Au

pyrite + quartz

age)

2008

Group silty slates 3

Chanzip

Sinian

<5 t

native gold + pyrite +

2

ing

Jiangkou

Au

arsenopyrite + galena + quartz

Formation epimetamorphi c sedimentary and volcanic rocks

3

Qingsha

Sinian

<5 t

native gold + pyrite +

3

ndong

Jiangkou

Au

arsenopyrite + galena + sphalerite

Formation

+ bournonite + quartz

epimetamorphi c sedimentary and volcanic rocks 3

Banbian

Neoproterozoi

<5 t

native gold+ limonite + pyrite +

4

shan

c Banxi Group

Au

quartz

epimetamorphi c sedimentary and volcanic rocks 3

Paomap

Neoproterozoi

<5 t

native gold + pyrite +

5

ing

c Lengjiaxi

Au

arsenopyrite + quartz + sericite

Neoproterozoi

<5 t

native gold + stibnite +

c Banxi Group

Au

arsenopyrite + pyrite + quartz

stibnite + pyrite + quartz

Group epimetamorphi c sandstone, siltstone and slates 3

Shouxi

6

epimetamorphi c sedimentary and volcanic rocks 3

Xikuang

Devonian–Car

2 Mt

7

shan

boniferous

Sb

limestone-sand

156–124 Ma (calcite Sm-Nd

Peng et

isochron age)

al., 2003b

stones 3

Dong‘a

Cambrian

0.075

stibnite + pyrite + sphalerite +

8

n

slates

Mt

boulangerite +galena +

Sb @

chalcopyrite + valentinite +

3.8%

stibiconite

Table 2. LA-ICPMS analytical results of zircon U–Pb dating for the Banxi antimony deposit. Analyzed Isotope ratio 207Pb/235U Spot No. 207Pb/206Pb 1σ Sample BX4-5, early quartz-stibnite ore BX4-5-1 0.1533 0.0041 7.1215 BX4-5-2 0.0650 0.0026 1.1302 BX4-5-3 0.0546 0.0015 0.2381 BX4-5-4 0.0643 0.0044 1.1281 BX4-5-5 0.1358 0.0033 7.1786 BX4-5-6 0.1227 0.0033 5.9158 BX4-5-7 0.0650 0.0027 1.1346 BX4-5-8 0.1212 0.0035 5.8160 BX4-5-9 0.1564 0.0049 9.3536 BX4-5-10 0.1593 0.0041 9.2084 BX4-5-11 0.1206 0.0040 5.9729 BX4-5-12 0.1272 0.0037 5.7093 BX4-5-13 0.1207 0.0044 5.4387 BX4-5-14 0.0648 0.0044 1.1346 BX4-5-16 0.2326 0.0057 13.8952 BX4-5-17 0.0655 0.0044 1.1407 BX4-5-18 0.1094 0.0037 4.7969 BX4-5-19 0.0652 0.0029 1.1486 Sample BX4-6, late quartz-stibnite ore BX4-6-01 0.0631 0.0065 1.1088 BX4-6-02 0.0717 0.0047 1.2620 BX4-6-03 0.0574 0.0031 1.0127 BX4-6-04 0.1209 0.0022 6.0445 BX4-6-05 0.1617 0.0032 10.2206 BX4-6-06 0.0632 0.0031 1.1158 BX4-6-07 0.1206 0.0025 5.3715 BX4-6-08 0.1193 0.0024 3.7181 BX4-6-09 0.0760 0.0036 1.5300 BX4-6-10 0.0716 0.0045 1.2599 BX4-6-11 0.1277 0.0032 6.5668 BX4-6-12 0.1264 0.0030 6.4044 BX4-6-13 0.1147 0.0024 2.1756 BX4-6-14 0.1572 0.0028 9.8681 BX4-6-15 0.0738 0.0059 1.3033 BX4-6-16 0.0702 0.0048 1.2432 BX4-6-17 0.2342 0.0040 18.8633 BX4-6-18 0.1249 0.0028 6.2110 BX4-6-19 0.1599 0.0025 10.2806 BX4-6-20 0.1642 0.0029 4.1550 Sample BX7-3, hydrothermally altered tuff BX7-3-1 0.0690 0.0674 1.3661 BX7-3-2 0.0686 0.0975 1.3546 BX7-3-3 0.0645 0.0042 1.1199 BX7-3-4 0.0649 0.0062 1.1312 BX7-3-5 0.0663 0.0067 1.1520 BX7-3-6 0.0648 0.0024 1.1404 BX7-3-7 0.0651 0.0058 1.1410 BX7-3-8 0.0656 0.0059 1.1485 BX7-3-9 0.0664 0.0042 1.1587 BX7-3-10 0.0653 0.0022 1.1401 BX7-3-12 0.0651 0.0020 1.1343 BX7-3-13 0.4776 0.0402 11.6273 BX7-3-14 0.6202 0.0256 21.1523 BX7-3-15 0.0645 0.0036 1.1304 BX7-3-16 0.0680 0.0537 1.3457 BX7-3-17 0.0655 0.0071 1.1468 BX7-3-18 0.1846 0.0314 1.1691 BX7-3-19 0.0665 0.0041 1.1579 BX7-3-20 0.0646 0.0053 1.1203 BX7-3-21 0.0643 0.0072 1.1315 BX7-3-22 0.5001 0.0887 19.5856 BX7-3-23 0.0657 0.0039 1.1548

Pb/238U 1σ

Apparent age (Ma) 207Pb/206Pb 1σ 207Pb/235U 1σ

1σ

206

Pb/238U 1σ

0.5438 0.0067 0.0132 0.0073 0.5419 0.3667 0.0051 0.4421 0.5749 0.4990 0.4700 0.3961 0.3834 0.0081 0.8170 0.0069 0.3069 0.0096

0.3369 0.1261 0.0317 0.1273 0.3835 0.3496 0.1265 0.3481 0.4338 0.4193 0.3593 0.3256 0.3268 0.1269 0.4332 0.1263 0.3181 0.1277

0.0217 0.0027 0.0016 0.0022 0.0165 0.0185 0.0019 0.0233 0.0247 0.0192 0.0267 0.0195 0.0182 0.0030 0.0213 0.0020 0.0166 0.0018

2383 775 394 751 2174 1996 774 1974 2417 2448 1965 2060 1967 767 3070 790 1789 782

51 45 55 63 44 48 43 52 53 44 58 52 64 73 59 63 62 56

2127 768 217 767 2134 1964 770 1949 2373 2359 1972 1933 1891 770 2743 773 1784 777

68 8 11 10 51 54 10 66 56 50 68 60 60 8 87 7 54 6

1872 766 201 772 2092 1933 768 1926 2323 2257 1979 1817 1823 770 2320 767 1780 775

104 19 10 13 77 88 17 111 111 87 127 95 88 42 91 43 81 18

0.1037 0.0694 0.0513 0.1155 0.2054 0.0545 0.1228 0.0968 0.0686 0.0728 0.1646 0.1561 0.0462 0.1876 0.1072 0.1017 0.3740 0.1424 0.1737 0.1009

0.1275 0.1277 0.1279 0.3625 0.4584 0.1281 0.3220 0.2239 0.1470 0.1275 0.3729 0.3676 0.1368 0.4552 0.1281 0.1284 0.5805 0.3605 0.4664 0.1843

0.0025 0.0020 0.0021 0.0038 0.0046 0.0019 0.0046 0.0039 0.0023 0.0025 0.0047 0.0045 0.0013 0.0057 0.0022 0.0027 0.0069 0.0037 0.0047 0.0044

710 977 508 1969 2473 715 1965 1946 1095 976 2067 2048 1876 2426 1035 933 3081 2027 2455 2500

110 131 123 32 34 108 37 37 94 125 45 41 43 31 163 103 28 42 27 30

758 829 710 1982 2455 761 1880 1575 942 828 2055 2033 1173 2423 847 820 3035 2006 2460 1665

54 31 26 17 19 26 20 21 28 33 22 21 15 18 47 33 19 19 16 20

773 775 776 1994 2433 777 1800 1302 884 774 2043 2018 826 2418 777 779 2951 1985 2468 1090

14 12 12 18 20 11 23 20 13 14 22 21 7 23 13 12 28 20 21 24

0.0159 0.0126 0.0071 0.0069 0.0082 0.0070 0.0093 0.0118 0.0059 0.0094 0.0087 1.2247 2.1198 0.0085 0.0162 0.0066 0.3012 0.0085 0.0103 0.0061 7.0137 0.0104

0.1437 0.1432 0.1259 0.1264 0.1260 0.1276 0.1272 0.1270 0.1265 0.1267 0.1263 0.1750 0.2417 0.1271 0.1434 0.1269 0.0406 0.1262 0.1258 0.1277 0.2290 0.1275

0.0031 0.0027 0.0023 0.0022 0.0031 0.0012 0.0024 0.0023 0.0018 0.0021 0.0020 0.0112 0.0198 0.0023 0.0019 0.0017 0.0037 0.0018 0.0016 0.0020 0.0534 0.0016

899 887 759 770 815 768 776 793 818 783 777 4174 4556 759 869 792 2694 821 761 751 4242 798

257 341 78 53 81 94 101 98 95 74 82 126 60 62 291 46 285 40 38 64 265 89

874 870 763 768 778 773 773 777 781 773 770 2575 3146 768 866 776 786 781 763 768 3071 780

13 17 10 8 10 8 8 5 5 6 9 98 97 10 13 11 141 9 9 5 346 10

865 863 764 767 765 774 772 771 768 769 767 1040 1396 771 864 770 257 766 764 775 1329 774

45 67 30 21 16 49 15 28 33 41 43 62 103 47 32 48 23 38 44 15 280 41

206

51

Table 3. EPMA results of zircon major element compositions for the Banxi antimony deposit (%). Analyzed Spot No.

F

SiO2

Dy2O3

Y2O3

Er2O3

P2O5

Lu2O3

ZrO2

HfO2

ThO2

UO2

Total

Sample BX4-5, early quartz-stibnite ore BX4-5-1

0.14

31.71

0.07

0.17

0.08

0.06

0.11

65.93

2.06

0.12

0.01

100.45

BX4-5-2

0.16

31.51

0.01

0.11

0.04

0.20

0.02

65.53

2.52

0.01

0.04

100.14

BX4-5-3

0.12

31.50

0.01

0.07

0.01

0.03

0.01

65.41

2.13

0.07

0.15

99.47

BX4-5-4

0.07

31.76

0.01

0.08

0.01

0.05

0.13

65.25

3.36

0.08

0.15

100.93

BX4-5-5

0.17

32.31

0.01

0.02

0.06

0.04

0.01

65.18

2.56

0.01

0.01

100.35

Sample BX7-3, hydrothermally altered tuff BX7-3-1

0.15

31.45

0.06

0.34

0.01

0.12

0.10

66.19

1.65

0.08

0.03

100.16

BX7-3-2

0.23

31.44

0.01

0.16

0.01

0.05

0.02

66.31

3.13

0.01

0.08

101.41

BX7-3-3

0.06

32.02

0.01

0.01

0.02

0.06

0.01

65.93

3.33

0.01

0.05

101.47

BX7-3-4

0.16

31.71

0.01

0.39

0.08

0.10

0.13

65.67

1.94

0.01

0.02

100.21

BX7-3-5

0.20

32.13

0.01

0.17

0.17

0.10

0.14

66.00

2.40

0.01

0.07

101.39

BX7-3-6

0.18

31.50

0.01

0.27

0.01

0.36

0.02

65.63

2.64

0.01

0.20

100.81

Banxi Group unaltered wall rock BX6-2-1

0.01

31.57

0.04

0.27

0.16

0.12

0.01

63.73

3.08

0.11

0.07

99.16

BX6-2-2

0.01

31.52

0.09

0.53

0.06

0.16

0.08

64.83

2.39

0.13

0.11

99.90

BX6-2-3

0.15

31.72

0.01

0.66

0.08

0.15

0.01

65.48

1.93

0.10

0.05

100.32

BX6-2-4

0.05

31.78

0.08

0.38

0.01

0.09

0.01

65.50

1.72

0.09

0.06

99.75

BX6-2-5

0.01

32.02

0.12

0.11

0.03

0.05

0.03

66.40

2.42

0.01

0.01

101.18

BX6-2-6

0.01

31.61

0.19

0.40

0.01

0.09

0.14

65.40

1.69

0.09

0.01

99.62

BX6-2-7

0.09

31.94

0.16

0.36

0.15

0.11

0.17

65.59

1.81

0.01

0.01

100.36

BX6-2-8

0.01

31.46

0.03

0.18

0.04

0.07

0.11

66.30

2.03

0.09

0.07

100.38

BX6-9-1

0.06

31.48

0.04

0.32

0.06

0.30

0.06

65.62

2.32

0.11

0.04

100.42

BX6-9-2

0.01

32.14

0.01

0.10

0.16

0.13

0.14

65.54

1.86

0.05

0.01

100.11

BX6-9-3

0.12

31.32

0.01

0.06

0.17

0.15

0.07

65.50

2.88

0.01

0.01

100.27

BX6-9-4

0.07

31.18

0.01

0.68

0.11

0.07

0.04

64.14

2.86

0.08

0.09

99.32

BX6-9-5

0.01

31.83

0.01

0.18

0.13

0.12

0.01

65.49

2.42

0.01

0.02

100.18

BX6-9-6

0.01

31.42

0.01

0.24

0.02

0.15

0.19

65.21

2.70

0.03

0.05

100.00

BX6-9-7

0.00

31.61

0.05

0.13

0.01

0.06

0.01

65.95

3.68

0.01

0.01

101.48

BX6-9-8

0.03

31.93

0.01

0.73

0.13

0.21

0.01

64.07

2.03

0.11

0.03

99.29

52

Table 4. LA-ICPMS results of zircon element compositions for the Banxi antimony deposit (ppm). Spot No. Hf Y Nb Ta Sample BX4-5, early quartz-stibnite ore BX4-5-1 10698 752 1.71 0.75 BX4-5-2 14782 2919 14.1 6.03 BX4-5-3 8775 3902 8.04 3.23 BX4-5-4 10825 1810 7.57 2.92 BX4-5-5 11410 674 2.92 1.65 BX4-5-6 11727 813 2.52 1.18 BX4-5-7 9831 1213 2.63 0.93 BX4-5-8 10818 564 1.70 0.82 BX4-5-9 9474 1308 1.69 0.94 BX4-5-10 10924 773 1.67 1.09 BX4-5-11 9931 1054 2.67 0.82 BX4-5-12 11831 1816 2.28 1.05 BX4-5-13 8869 449 1.45 0.76 BX4-5-14 11294 1392 5.32 1.89 BX4-5-15 5732 1133 1.26 0.51 BX4-5-16 10758 2022 3.71 1.28 BX4-5-17 10476 3100 4.42 1.63 BX4-5-18 11769 532 1.88 0.78 BX4-5-19 10850 553 1.26 0.88 Sample BX4-6, late quartz-stibnite ore BX4-6-01 9359 1904 4.76 1.32 BX4-6-02 8504 923 2.27 0.60 BX4-6-03 8599 1483 2.25 0.64 BX4-6-04 10641 510 3.93 1.23 BX4-6-05 9383 1072 2.15 0.81 BX4-6-06 9102 1493 3.26 0.93 BX4-6-07 8333 754 1.71 0.44 BX4-6-08 9656 2274 5.28 1.01 BX4-6-09 10094 452 0.62 0.32 BX4-6-10 8473 1077 0.43 0.15 BX4-6-11 8877 710 1.51 0.48 BX4-6-12 9756 414 1.55 0.51 BX4-6-13 9885 8464 9.9 1.66 BX4-6-14 9779 834 2.83 0.97 BX4-6-15 8431 626 1.41 0.51 BX4-6-16 9410 750 1.98 0.80 BX4-6-17 8275 1201 3.29 1.25 BX4-6-18 9362 731 3.12 0.70 BX4-6-19 8339 637 1.38 0.56 BX4-6-20 10627 4534 20.1 10.0 Sample BX7-3, hydrothermally altered tuff BX7-3-1 702 115 0.064 0.089 BX7-3-2 3845 920 1.16 0.96 BX7-3-3 5538 2381 1.78 0.56 BX7-3-4 7993 3750 2.41 0.84 BX7-3-5 4655 2250 5.15 1.02 BX7-3-6 2062 971 1.71 0.48 BX7-3-7 3977 741 1.48 0.44 BX7-3-8 9228 5785 6.43 1.78 BX7-3-9 3737 2485 1.22 0.36 BX7-3-10 7285 1941 1.36 0.55 BX7-3-11 2554 745 0.86 0.17 BX7-3-12 7002 1335 2.16 0.75 BX7-3-13 2897 1346 0.75 0.18 BX7-3-14 7328 2202 1.67 0.44 BX7-3-15 6498 4332 5.50 1.30 BX7-3-16 2932 855 1.10 0.30 BX7-3-17 6997 2236 1.56 0.53 BX7-3-18 22218 589 4.12 7.34 BX7-3-19 6830 2503 2.07 0.64 BX7-3-20 3151 1570 1.68 0.19 BX7-3-21 6077 4110 5.14 1.30 BX7-3-22 3050 1968 1.04 0.32 BX7-3-23 11503 1187 2.64 1.82

Ti

Pb

Th

U

Th/U

La

Ce

Pr

Nd

Sm

Eu

5.70 8.94 4.89 21.2 9.42 5.43 13.5 9.62 5.69 4.91 5.33 7.61 13.6 4.68 92.8 9.17 5.01 6.51 5.80

163 136 296 358 360 136 108 136 169 596 287 239 125 66.6 12.4 568 118 200 33.5

225 420 3449 796 372 183 406 184 125 476 450 324 180 212 56.2 493 469 277 105

242 577 2652 1203 361 146 219 132 178 690 216 314 119 247 59.0 608 289 177 154

0.93 0.73 1.30 0.66 1.03 1.25 1.85 1.40 0.70 0.69 2.08 1.03 1.52 0.86 0.95 0.81 1.62 1.57 0.68

0.85 176 6.64 101 0.12 0.086 1.07 0.026 0.050 0.49 0.67 0.71 0.58 0.10 0.15 12.0 0.30 0.12 7.36

13.0 213 70.8 155 17.0 28.9 23.9 38.0 11.5 41.9 34.8 28.4 29.2 51.7 8.08 33.0 114 26.4 22.6

0.90 52.8 10.4 37.2 0.43 0.33 1.31 0.32 0.55 0.69 1.80 0.94 0.63 0.12 0.42 5.33 1.26 0.43 1.74

4.21 134 47.9 95.7 2.53 2.91 6.33 2.47 4.68 3.62 11.6 7.05 4.69 1.21 3.23 19.1 10.4 3.72 4.02

6.46 40.0 57.3 38.0 4.61 5.57 9.23 4.99 8.06 5.09 17.2 13.4 6.92 3.42 6.01 20.5 18.2 5.70 2.66

2.56 0.74 4.76 29.7 0.51 0.73 2.74 0.95 1.50 2.60 7.23 2.00 1.49 0.73 1.50 8.95 4.60 1.85 0.58

19.8 14.4 13.5 16.3 9.5 14.9 21.6 80 75.9 30.3 32.4 11.9 41.7 10.0 9.1 17.6 16.6 29.9 18.2 70

22 17 10.9 112 106 22 149 211 11.2 6.8 76 61 155 132 10.0 21 157 89 142 176

70 57 36.9 119 71 85 239 731 29.1 21.7 91 72 924 119 25.5 69 110 133 107 823

49.2 38 43.4 154 140 56 147 254 40.9 28.9 74 66 375 124 42 69 93 52 161 564

1.42 1.52 0.85 0.77 0.51 1.52 1.63 2.87 0.71 0.75 1.23 1.09 2.46 0.96 0.60 1.00 1.19 2.55 0.66 1.46

231 4.29 0.020 0.022 49.8 0.12 0.27 37.5 0.67 0.01 50 0.011 48.1 0.027 3.0 15.3 1306 1.02 0.017 5.89

514 52 30.6 23.7 92 61 31.5 94 9.9 1.50 114 19.4 138 20.3 15.1 50 2177 44 15.5 59

160 1.79 0.20 0.13 24.3 0.46 1.07 19.4 0.40 0.15 29.2 0.06 30.4 0.18 1.4 7.9 523 1.04 0.26 10.5

540 6.4 2.71 2.39 82 5.25 8.1 67.6 1.45 2.68 95 1.66 118 2.50 5.4 21 1375 6.8 2.74 48.2

135 4.7 5.0 3.59 16.3 11.9 8.0 36.9 1.54 5.3 18.9 1.93 113 3.74 2.06 6.5 183 6.3 4.13 56

1.50 1.47 1.75 0.23 1.33 4.63 4.15 18.0 0.41 1.72 1.30 0.37 57 0.73 0.99 1.16 8.6 1.69 0.78 41.2

0.60 2.01 12.2 15.6 10.1 4.73 2.18 6.32 4.40 3.72 3.40 5.39 4.06 8.39 4.21 1.55 7.07 7.51 4.33 48.6 44.1 23.5 10.2

28.3 186 92 103 88 79 75.6 322 90 64.8 369 171 70.5 299 189 35.9 69.8 162 128 75.9 97 56.0 465

4.40 202 103 241 341 95.6 46.9 930 127 100 54.6 218 37.4 90.9 444 55.4 94.2 12.2 117 171 207 46.3 603

55.4 610 106 250 258 77.0 65.8 401 64.2 121 45.5 151 27.6 80.2 294 65.7 91.1 936 133 290 200 41.2 829

0.08 0.33 0.97 0.96 1.33 1.24 0.71 2.32 1.97 0.83 1.20 1.44 1.35 1.13 1.51 0.84 1.03 0.01 0.88 0.59 1.03 1.12 0.73

0.024 5.74 54.7 34.9 1.84 21.5 0.047 0.33 3.14 0.13 0.14 11.3 0.26 0.22 0.33 0.41 0.11 0.29 0.11 0.45 2.16 5.72 0.97

0.096 30.8 70.5 57.6 21.2 27.1 4.44 72.0 15.1 7.17 3.21 30.1 2.54 6.08 26.4 4.74 7.37 0.66 8.61 14.0 19.1 10.0 17.9

0.26 6.26 20.5 14.6 2.10 6.40 0.11 0.97 1.85 0.30 0.13 3.47 0.44 0.55 1.14 0.29 0.36 0.16 0.48 0.52 1.66 2.61 0.30

0.50 20.7 61.7 44.8 8.36 20.0 0.93 8.65 8.86 2.53 1.09 9.66 3.47 4.74 9.52 1.92 3.40 0.57 4.67 3.77 10.4 9.32 1.33

0.17 7.65 22.5 25.4 9.55 8.28 2.12 19.9 11.3 5.46 2.31 6.38 8.42 8.87 20.7 3.16 6.46 0.93 9.75 9.11 21.1 10.9 2.68

0.023 3.46 4.38 4.29 4.62 1.30 0.45 6.80 4.26 2.64 0.96 2.08 4.18 3.92 4.96 0.62 3.15 0.39 2.78 4.95 8.13 5.52 0.34

53

Table 4. Continued. Spot No. Gd Tb Dy Ho Er Sample BX4-5,early quartz-stibnite ore BX4-5-1 23.9 7.15 80.2 26.0 113 BX4-5-2 74.1 22.5 277 103 463 BX4-5-3 131 38.5 424 142 605 BX4-5-4 62.4 18.5 199 64.8 271 BX4-5-5 17.4 5.75 65.3 22.8 94.9 BX4-5-6 21.1 6.84 82.3 29.7 128 BX4-5-7 33.7 11.5 136 45.4 187 BX4-5-8 18.0 5.38 59.8 20.0 83.1 BX4-5-9 35.8 11.3 135 47.5 197 BX4-5-10 19.6 5.96 70.6 25.9 116 BX4-5-11 47.2 12.0 123 36.9 142 BX4-5-12 48.5 15.3 183 63.8 274 BX4-5-13 19.0 5.19 54.7 16.7 65.4 BX4-5-14 21.1 7.99 116 47.2 229 BX4-5-15 26.2 8.81 113 40.7 175 BX4-5-16 62.0 18.5 203 66.8 288 BX4-5-17 68.3 21.9 282 104 485 BX4-5-18 17.5 5.33 59.0 19.0 78.4 BX4-5-19 9.50 3.14 43.0 17.7 90.8 Sample BX4-6, late quartz-stibnite ore BX4-6-01 173 33 249 71 248 BX4-6-02 19.0 5.8 77 29.8 143 BX4-6-03 27.3 9.5 126 51 238 BX4-6-04 16.3 4.6 53 17.9 72 BX4-6-05 32.5 8.7 103 36.9 161 BX4-6-06 62 16.4 167 50 193 BX4-6-07 25.9 7.5 77 25.1 100 BX4-6-08 152 37.9 307 75 238 BX4-6-09 8.5 3.16 38.0 15.1 70 BX4-6-10 26.7 8.5 104 38.5 161 BX4-6-11 32.4 7.5 79 24.3 94 BX4-6-12 9.7 3.29 38.3 14.5 62 BX4-6-13 505 131 1102 270 804 BX4-6-14 19.3 6.4 78 27.5 123 BX4-6-15 11.7 3.97 49 19.4 96 BX4-6-16 16.4 5.6 65 25.2 112 BX4-6-17 154 23.7 169 42.6 147 BX4-6-18 21.8 6.3 72 25.4 108 BX4-6-19 16.4 4.8 54 20.3 93 BX4-6-20 246 66 584 153 540 Sample BX7-3, hydrothermally altered tuff BX7-3-1 1.16 0.59 8.63 3.34 16.4 BX7-3-2 19.5 6.92 82.7 29.2 133 BX7-3-3 60.8 19.3 225 78.7 325 BX7-3-4 89.9 29.4 357 130 552 BX7-3-5 39.2 14.5 179 62.5 312 BX7-3-6 23.7 7.36 87.5 30.7 134 BX7-3-7 11.6 4.68 61.9 24.6 116 BX7-3-8 110 39.5 506 190 868 BX7-3-9 54.2 19.2 231 84.3 357 BX7-3-10 36.0 13.0 159 56.6 251 BX7-3-11 11.8 4.74 61.3 24.4 114 BX7-3-12 26.4 9.93 114 40.0 178 BX7-3-13 40.8 13.5 169 46.5 177 BX7-3-14 45.3 16.5 202 74.2 328 BX7-3-15 105 36.3 428 149 623 BX7-3-16 15.2 5.68 75.9 28.7 125 BX7-3-17 39.9 15.0 194 75.7 342 BX7-3-18 9.17 4.55 59.1 18.2 63.1 BX7-3-19 52.9 18.7 234 86.1 370 BX7-3-20 46.1 15.4 163 47.1 203 BX7-3-21 104 37.1 419 134 502 BX7-3-22 51.2 17.6 185 59.7 184 BX7-3-23 15.3 6.50 88.3 36.1 173

Tm

Yb

Lu

ΣREE LREE

HREE

LREE/HREE

Eu/Eu*

Ce/Ce*

26.1 107 139 63.8 21.1 29.2 41.1 18.6 42.5 27.6 30.3 61.2 13.8 56.5 38.8 64.4 118 18.5 24.6

256 990 1274 601 186 269 365 170 377 274 277 577 129 579 364 604 1175 171 275

46.9 164 207 97.0 30.8 45.5 54.1 28.5 62.6 47.3 43.0 92.0 20.6 102 60.2 101 209 28.4 56.3

606 2817 3158 1836 470 651 919 450 935 642 784 1366 368 1216 846 1507 2612 436 559

28.0 617.1 197.8 457.2 25.2 38.6 44.6 46.7 26.4 54.4 73.3 52.5 43.5 57.3 19.4 98.9 148.5 38.2 39.0

578.4 2200.3 2960.6 1378.4 444.5 612.3 874.2 403.5 909.1 587.5 711.0 1313.8 324.2 1158.7 826.9 1408.0 2464.0 397.5 520.3

0.05 0.28 0.07 0.33 0.06 0.06 0.05 0.12 0.03 0.09 0.10 0.04 0.13 0.05 0.02 0.07 0.06 0.10 0.07

0.56 0.04 0.16 1.85 0.15 0.18 0.42 0.27 0.23 0.70 0.73 0.21 0.37 0.20 0.31 0.71 0.35 0.52 0.32

3.26 0.54 1.68 0.62 10.96 24.50 4.26 35.48 6.27 14.72 5.22 7.21 10.55 96.72 5.21 1.01 25.49 16.93 1.50

47 34.5 58 15.7 35.6 41.1 23.3 43.4 16.7 35.2 20.1 14.0 137 29.1 25.9 29.0 29.6 24.9 22.0 112

397 342 552 143 328 368 211 344 168 316 179 137 1018 278 289 288 250 231 221 973

65 63 101 23.6 55 63 34.6 49.0 29.9 53 28.1 22.7 126 43.4 52 44.6 40.8 37.9 39.7 144

2864 785 1204 377 1026 1043 557 1520 363 755 773 325 4596 632 575 688 6427 588 495 3039

1580.2 70.8 40.3 30.1 265.4 82.9 53.1 273.0 14.3 11.4 308.4 23.4 504.3 27.5 27.9 101.7 5571.1 60.8 23.4 220.3

1284.1 714.5 1163.7 346.5 760.5 960.3 504.1 1246.7 349.1 743.6 464.3 301.2 4091.8 604.2 547.0 586.1 856.4 527.7 471.9 2818.7

1.23 0.10 0.03 0.09 0.35 0.09 0.11 0.22 0.04 0.02 0.66 0.08 0.12 0.05 0.05 0.17 6.51 0.12 0.05 0.08

0.03 0.41 0.36 0.08 0.17 0.42 0.80 0.63 0.28 0.36 0.16 0.22 0.61 0.21 0.48 0.33 0.15 0.40 0.25 0.91

0.63 4.61 45.93 53.98 0.64 37.04 8.30 0.84 4.56 3.05 0.71 88.27 0.87 33.49 1.82 1.11 0.65 9.43 17.95 1.41

4.02 34.0 69.3 125 62.3 29.7 27.4 204 78.3 61.6 26.2 43.1 36.4 73.9 135 28.7 79.1 12.5 92.7 39.6 106 36.3 46.0

40.0 350 622 1130 575 267 263 1872 686 535 245 405 308 675 1175 265 776 101 769 382 943 294 466

7.01 61.5 105 195 96.4 46.5 48.2 337 120 95.9 44.0 75.1 50.9 120 195 45.8 131 16.4 131 73.4 148 43.3 87.9

82 791 1739 2790 1388 711 566 4236 1675 1226 538 955 862 1560 2911 601 1673 287 1781 1003 2455 916 943

1.1 74.6 234.3 181.5 47.6 84.5 8.1 108.6 44.5 18.2 7.8 63.0 19.3 24.4 63.1 11.1 20.9 3.0 26.4 32.8 62.6 44.0 23.6

81.1 716.4 1504.6 2608.1 1340.5 626.0 557.8 4127.7 1630.1 1207.9 530.6 892.0 842.3 1535.8 2847.9 589.9 1652.4 284.4 1754.7 970.1 2392.9 871.6 919.2

0.01 0.10 0.16 0.07 0.04 0.14 0.01 0.03 0.03 0.02 0.01 0.07 0.02 0.02 0.02 0.02 0.01 0.01 0.02 0.03 0.03 0.05 0.03

0.12 0.82 0.34 0.24 0.63 0.27 0.22 0.35 0.44 0.43 0.46 0.42 0.57 0.48 0.26 0.23 0.46 0.26 0.30 0.60 0.44 0.59 0.13

0.11 1.12 0.52 0.63 2.32 0.56 11.07 20.33 1.51 6.31 5.54 1.17 1.46 2.94 6.43 3.24 5.59 0.75 5.06 6.17 2.34 0.63 8.12

54

Table 5. LA-MC-ICPMS analytical results of zircon Lu–Hf isotopic compositions for the Banxi antimony deposit. Spot No.

Hf/177Hf

176

1σ

Lu/177Hf

176

1σ

176

Yb/177Hf

1σ

Age (Ma)

εHf(t) TDM1

TDM2

0.000061 0.000007 0.000061 0.000003 0.000003 0.000016 0.000021 0.000002 0.000022 0.000023 0.000223

0.056201 0.057007 0.076357 0.016312 0.020038 0.035150 0.022909 0.025235 0.103332 0.103414 0.057540

0.003131 0.000753 0.002336 0.000473 0.000277 0.001341 0.001448 0.000364 0.001384 0.002528 0.005060

1872 767 771 2094 1926 1933 2323 1817 764 766 768

–17.0 0.6 –26.7 –15.8 –8.6 –3.8 –13.0 –6.3 1.7 1.5 1.2

2930 1312 2400 3054 2642 2469 3144 2464 1280 1287 1297

3344 1522 3013 3457 2941 2687 3485 2731 1462 1470 1491

0.000013 0.000017 0.000001 0.000002 0.000002 0.000012 0.000009 0.000002 0.000010 0.000019

0.054097 0.055843 0.009770 0.023650 0.024325 0.016338 0.015237 0.011662 0.020525 0.026672

0.000340 0.000269 0.000073 0.000176 0.000238 0.000297 0.000492 0.000089 0.000102 0.000488

775 776 1994 2433 777 774 2043 2018 777 779

–9.2 6.4 –9.8 2.8 –12.7 3.7 –7.6 –9.0 –15.8 –10.1

1720 1095 2744 2647 1837 1190 2704 2736 1954 1738

2249 1271 3210 2776 2473 1444 3111 3180 2663 2311

0.000137 0.000078 0.000289 0.000048 0.000322 0.000103 0.000016 0.002800 0.000111 0.000167 0.000418 0.000244

0.082872 0.128937 0.184928 0.104893 0.176445 0.074611 0.120946 0.236787 0.128171 0.106917 0.146347 0.160122

0.003094 0.001383 0.009805 0.001018 0.009301 0.002808 0.000589 0.032790 0.002419 0.003466 0.016815 0.008417

767 764 769 771 761 1396 769 761 765 774 771 773

18.4 22.8 18.0 23.6 22.9 4.8 22.8 21.8 23.4 23.1 23.2 23.0

595 395 598 375 375 1694 397 401 364 397 374 381

537 291 561 252 281 1793 293 343 256 280 271 286

Sample BX4-5, early quartz-stibnite ore BX4-5-01 BX4-5-02 BX4-5-03 BX4-5-04 BX4-5-05 BX4-5-06 BX4-5-07 BX4-5-08 BX4-5-09 BX4-5-10 BX4-5-11

0.281152 0.282329 0.281559 0.281015 0.281328 0.281471 0.280955 0.281466 0.282372 0.282368 0.282352

0.000032 0.000020 0.000028 0.000020 0.000019 0.000020 0.000019 0.000018 0.000023 0.000021 0.000109

0.001092 0.001278 0.001502 0.000311 0.000393 0.000701 0.000438 0.000509 0.002084 0.002138 0.001746

Sample BX4-6, late quartz-stibnite ore BX4-6-01 BX4-6-02 BX4-6-03 BX4-6-04 BX4-6-05 BX4-6-06 BX4-6-07 BX4-6-08 BX4-6-09 BX4-6-10

0.282055 0.282497 0.281249 0.281344 0.281940 0.282400 0.281286 0.281258 0.281852 0.282014

0.000037 0.000033 0.000027 0.000033 0.000034 0.000029 0.000031 0.000030 0.000031 0.000031

0.001741 0.001904 0.000302 0.000739 0.000809 0.000529 0.000439 0.000359 0.000736 0.000882

Sample BX7-3, hydrothermally altered tuff BX7-3-01 BX7-3-02 BX7-3-03 BX7-3-04 BX7-3-05 BX7-3-06 BX7-3-07 BX7-3-08 BX7-3-09 BX7-3-10 BX7-3-11 BX7-3-12

0.282850 0.282996 0.282884 0.283003 0.283016 0.282102 0.282995 0.283016 0.283018 0.282989 0.283014 0.283013

0.000033 0.000022 0.000377 0.000029 0.000150 0.000033 0.000030 0.001431 0.000030 0.000040 0.000483 0.000128

0.002599 0.004091 0.005788 0.003258 0.005095 0.002663 0.004102 0.007223 0.004336 0.003312 0.004665 0.005147

Highlights 1. Quartz-stibnite ores have the same zircon U–Pb age ranges as the Banxi host rocks. 2. Highly radiogenic Hf isotopes suggest a crystalline basement-derived fluid. 3. Deep-sourced fluid mixed with meteoric water resulted in Sb precipitation. 4. Changing of Lu–Hf systematics is ascribed to lattice breakdown of old zircons.a 55

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