Genesis of the Kangshan Au-polymetallic deposit, Xiong’ershan District, North China Craton: Constraints from fluid inclusions and C-H-O-S-Pb isotopes

doi:10.1016/j.oregeorev.2020.103815

Ore Geology Reviews

Volume 127, December 2020, 103815

https://doi.org/10.1016/j.oregeorev.2020.103815 Get rights and content

Highlights

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The ore-forming materials and fluids of the Kangshan deposit might be magmatic source.
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The Kangshan deposit is a moderate-low temperature hydrothermal Au-polymetallic deposit.
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The Kangshan deposit may formed in an extensional setting related to craton destruction.

Abstract

The Kangshan Au-polymetallic deposit, in the Xiong’ershan District of China, lies on the southern margin of the North China Craton. The orebodies are hosted in (E)NE–(W)SW-trending brittle faults formed during the Mesozoic, which crosscut Neoarchean metamorphic rocks and Mesoproterozoic volcanic rocks. The ore-forming process can be divided into three stages: a quartz ± pyrite stage (Stage 1), a quartz-polymetallic sulfide stage (Stage 2), and a quartz-calcite stage (Stage 3). Stage 2 includes two substages: a quartz-pyrite-chalcopyrite-electrum substage (Stage 2-1; the main Au mineralization stage) and a galena-sphalerite-pyrite-ankerite-Ag-bearing tetrahedrite ± chalcopyrite ± electrum substage (Stage 2-2; the main Pb-Zn-Ag mineralization stage). Four types of fluid inclusions have been identified in the Kangshan deposit: three-phase CO₂-rich inclusions, two-phase aqueous inclusions, one-phase vapor inclusions and one-phase aqueous inclusions. Inclusion microthermometric, laser Raman, and C-H-O-S-Pb isotope analyses were undertaken to clarify the properties of the ore-forming fluids, sources of these fluids and ore-forming materials, and mineral precipitation mechanisms. Laser Raman spectroscopic analysis indicate that the ore-forming fluids were formed in a NaCl-H₂O-CO₂ system. Inclusion homogenization temperatures and salinities are 130 °C–359 °C, and 0.53–11.46 wt% NaCl equivalent (eqv.), respectively. δ¹⁸O_fluid values calculated from the δ¹⁸O_SMOW and δD values of the inclusions in auriferous quartz veins are 1.0–9.0‰ and -92‰ to -67‰, respectively. δ¹³C_PDB and δ¹⁸O_SMOW values of ankerite are -4.89‰ to -3.67‰ and 12.0‰–13.9‰, respectively. Fluid C-H-O isotopic compositions indicate that the ore-forming fluids originated mainly from magmas, with minor addition of meteoric water. δ³⁴S values of the ore sulfides are 4.8‰–7.4‰; ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios of the ore sulfides are 17.625–17.889, 15.543–15.620, and 38.389–38.740, respectively. S-Pb isotopic compositions indicate that the ore-forming materials of the deposit originated from granitic magmas and host rocks. The Kangshan Au-polymetallic deposit is a medium–low-temperature hydrothermal deposit. Its mineralization may be related toEarly Cretaceous granite formed in an extensional tectonic setting caused by craton destruction on the southern margin of the North China Craton.

Graphical abstract

Introduction

The Xiong’ershan District (XD), in the middle of the Eastern Qinling Metallogenic Belt (EQMB), lies on the southern margin of the North China Craton (NCC). The XD is an important Au-producing area of China (Mao et al., 2002). To date, two types of Au-polymetallic deposit have been described in the XD: magmatic-hydrothermal and orogenic deposits, distinguished mainly by H-O-S-Pb isotopic compositions, ore-forming fluids, and mineralization ages. Magmatic-hydrothermal deposits are considered to have formed during a craton-destruction event in the Early Cretaceous ( Mao et al., 2002, Han et al., 2007, Gao et al., 2011, Zhai et al., 2012, Li et al., 2013b, Tang et al., 2013, Tang, 2014, Zhu et al., 2015, Tian et al., 2017, Zhang et al., 2018, Zhang et al., 2019), while orogenic deposits generally formed during the Triassic, apparently in association with the collision between the NCC and Yangtze Craton (YC) (Chen et al., 2004, Chen et al., 2006, Chen et al., 2008, Tang, 2014, Zhou et al., 2018a).

The Kangshan Au-polymetallic deposit is hosted in Neoarchean Taihua Group metamorphic rocks and Mesoproterozoic Xiong’er Group volcanic rocks. Controversy remains concerning the genesis of the Kangshan deposit: whether it is a magmatic-hydrothermal deposit (Fan et al., 1994a) or an orogenic Au deposit (Wang et al., 2001). Fan et al. (1994a) considered that the ore-forming fluids were magmatic-hydrothermal fluids, with ore-forming materials being derived from the Taihua Group; Wang et al. (2001) considered that the ore-forming fluids were metamorphic-hydrothermal fluids, with the ore-forming materials being derived from subducting slabs. Study of the Kangshan deposit continues with the aim of clarifying these issues.

Here we present new fluid inclusion and C-H-O-S-Pb isotopic data for the Kangshan Au-polymetallic deposit, which we use to trace the sources of ore-forming fluids and materials, and clarify the origins of the deposit.

Section snippets

Regional geology

The EQMB lies on the southern margin of the NCC (Fig. 1A) and has a complex multi-stage orogenic history (Meng and Zhang, 2000, Zhang et al., 2001, Dong et al., 2011). Strata in the EQMB comprise the Neoarchean Taihua, Mesoproterozoic Xiong’er and Guandaokou, and Neoproterozoic Luanchuan groups (Fig. 1B). The Taihua Group (2.8–2.6 Ga) comprises mainly metamorphic rocks, including gneiss, marble, quartzite, and amphibolite (Kröner et al., 1988, Xue et al., 1996). The Xiong’er Group (1.8–1.4 Ga)

Strata

The Kangshan deposit lies in the southwestern XD (Fig. 1B). Strata in the ore area include the Neoarchean Taihua and Mesoproterozoic Xiong’er groups, with some Quaternary strata distributed in valleys (Fig. 2). Au-polymetallic mineralization is hosted in the Neoarchean Taihua and Mesoproterozoic Xiong’er groups.

Structures

Faults are widely distributed in the Kangshan deposit, the largest of which is the Sanmen-Lingtai Fault (Fig. 2), which is the northernmost fault of the Machaoying Fault Zone. It is

Samples

Samples were collected from tunnels and outcrops in the Kangshan deposit. Doubly polished thin-sections (0.2 mm thick) were made from auriferous quartz veins and altered wall-rocks for petrographic study of compositions, textures, structures, and spatial distributions of minerals. Fluid inclusions microthermometric and vapor-phase laser Raman spectroscopic analyses were undertaken on 12 and 6 typical sections, respectively. Isotopic analyses were undertaken on 9 sulfide samples for S isotopes

Petrography

Fluid inclusions are widely developed in quartz veins of each ore-forming stage. Most are isolated or randomly clustered primary inclusions, with fairly regular shapes (polygonal, oval, or semicircular) in a size range of 3–15 μm (Fig. 8). Secondary and pseudo-secondary inclusions occur as intergranular arrays or aligned along microfractures in transgranular crystal trails (Roedder, 1984, Lu et al., 2004). Here we focus on the primary inclusions (Fig. 8), of which there are four types in the

Source and evolution of the ore-forming fluids

δD and δ¹⁸O_fluid values of quartz veins from the different hydrothermal stages are shown in Fig. 12, where Stage 1 values plot in or near the magmatic field. δ¹⁸O_fluid values gradually decrease over the later stages, suggesting a continuous influx of meteoric water during ore-formation.

δ¹³C_PDB and δ¹⁸O_SMOW values of ankerite formed in Stage 2-2 are shown in Fig. 13, where δ¹³C_PDB values (-4.89‰ to -3.67‰) plot within the range of magmatic and mantle C (from -5‰ to -2‰, Taylor, 1986), suggesting

Conclusions

(1)
Ore-forming fluids of the Kangshan Au-polymetallic deposit were formed in a moderate-low temperature, NaCl-H₂O-CO₂ magmatic-related system. Fluid immiscibility was the main process involved in Au precipitation, and fluid mixing in Pb-Zn-Ag precipitation.
(2)
Mineral C-H-O isotopic compositions indicate that the ore-forming fluids were derived mainly from magmatic fluids; S-Pb isotopic compositions indicate that the ore-forming materials may have originated from the magmas and host rocks.
(3)
Geological

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was financially supported by the National Key R & D Program of China (Grant No. 2016YFC0600109), and the State Key Laboratory of Lithospheric Evolution, IGGCAS (SKL-Z201905). We are indebted to all the geologists and staffs of the Kangshan Gold Mine for their hospitable assistance. We grated the kind help of He Zhang from the CUGB on the fluid inclusions microthermometric measurements, Mu Liu from the BRIUG on the Pb isotopic analysis. We appreciate Liangliang Huang for assistance of

References (115)

N.S. Belshaw et al.
A new variable dispersion double-focusing plasma mass spectrometer with performance illustrated for Pb isotopes
Int. J. Mass Spectrum.
(1998)
R.J. Bodnar
Revised equation and table for determining the freezing point depression of H₂O-NaCl solutions
Geochim. Cosmochim. Acta
(1993)
Y.J. Chen et al.
Isotope systematics and fluid inclusion studies of the Qiyugou breccia pipe–hosted gold deposit, Qinling Orogen, Henan province, China: implications for ore genesis
Ore Geol. Rev.
(2009)
Y.J. Chen et al.
The Shanggong gold deposit, Eastern Qinling Orogen, China: isotope geochemistry and implications for ore genesis
J. Asian Earth Sci.
(2008)
R.N. Clayton et al.
The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis
Geochim. Cosmochim. Acta
(1963)
L.W. Diamond
Review of the systematics of CO₂-H₂O fluid inclusions
Lithos
(2001)
Y.P. Dong et al.
Tectonic evolution of the Qinling orogen, China: Review and synthesis
J. Asian Earth Sci.
(2011)
L.J. Du et al.
Carbonoxygen isotopic geochemistry of the Yangla Cu skarn deposit, SW China: implications for the source and evolution of hydrothermal fluids
Ore Geol. Rev.
(2017)
H.R. Fan et al.
Fluid unmixing/immiscibility as an oreforming process in the giant REE-Nb-Fe deposit, Inner Mongolian, China: evidence from fluid inclusions
J. Geochem. Explor.
(2006)
I. Friedman
Deuterium content of natural waters and other substances
Geochim. Cosmochim. Acta
(1953)

R.J. Goldfarb et al.

Orogenic gold: common vs evolving fluid and metal sources through time

Lithos

(2015)

D.I. Groves et al.

Structural geometry of orogenic gold deposits: Implications for exploration of world-class and giant deposits

Geosci. Front.

(2018)

L.S. Hollister et al.

Phase equilibria in fluid inclusions from the Khtada Lake metamorphic complex

Geochim. Cosmochim. Acta

(1976)

V. Hurai

Fluid inclusion geobarometry: pressure corrections for immiscible H₂O-CH₄ and H₂O-CO₂ fluids

Chem. Geol.

(2010)

J.W. Li et al.

Giant Mesozoic gold provinces related to the destruction of the North China craton

Earth Planet. Sci. Lett.

(2012)

Q.R. Meng et al.

Geologic framework and tectonic evolution of the Qinling orogen, central China

Tectonophysics

(2000)

P. Muchez et al.

Extensional tectonics and the timing and formation of basin-hosted deposits in Europe

Ore Geol. Rev.

(2005)

G.N. Phillips et al.

Formation of gold deposits: Review and evaluation of the continuum model

Earth Sci. Rev.

(2009)

Y.F. Tian et al.

Genesis of the Dianfang breccia–hosted gold deposit, western Henan Province, China: constraints from geology, geochronology and geochemistry

Ore Geol. Rev.

(2017)

J. Veizer et al.

The nature of ¹⁸O/¹⁶O and ¹³C/¹²C secular trends in sedimentary carbonate rocks

Geochim. Cosmochim. Acta

(1976)

X.X. Wang et al.

Neoproterozoic, Paleozoic, and Mesozoic granitoid magmatism in the Qinling orogen, China: Constraints on orogenic process

J. Earth. Sci.

(2013)

F.Y. Wu et al.

Nature and significance of the Early Cretaceous giant igneous event in eastern China

Earth Planet. Sci. Lett.

(2005)

A. Yamaguchi et al.

Dynamic changes in fluid redox state associatedwith episodic fault rupture along amegasplay fault in a subduction zone

Earth Planet. Sci. Lett.

(2011)

Y.F. Yang et al.

Evolution of ore fluids in the Donggou giant porphyry Mo system, East Qinling, China, a new type of porphyry Mo deposit: evidence from fluid inclusion and H-O isotope systematics

Ore Geol. Rev.

(2015)

T. Baker

Emplacement depth and CO₂-rich fluid inclusions in intrusion-related gold deposits

Econ. Geol.

(2002)

D.L. Bryant et al.

Geochemical, age and isotopic constraints on the location of the Sino-Korean/Yangtze Suture and evolution of the Northern Dabie Complex, east central China

Geol. Soc. Am. Bull.

(2004)

J. Cao et al.

Geochronology, geochemistry and Sr-Nd-Hf isotopic compositions of granite porphyry in Leimengou Mo deposit, western Henan Province

Miner. Deposits

(2016)

J. Cao et al.

Geochronology, geochemistry and petrogenesis of the Mogou alkalic pluton in the East Qinling orogenic belt

Acta Petrol. Mineral.

(2015)

G.R. Carr et al.

Precise lead isotope fingerprinting of hydrothermal activity associated with Ordovician to Carboniferous metallogenic events in the Lachlan fold belt of New South Wales

Econ. Geol.

(1995)

Chen, Y.J., Fu, S.G., 1992. Gold Mineralization in West Henan. China Seismological Press, Beijing, pp. 1–234 (in...

Y.J. Chen et al.

Ore geology, fluid geochemistry and genesis of the Shanggong gold deposit, Eastern Qinling Orogen

China. Resour. Geol.

(2006)

Y.J. Chen et al.

Isotope geochemistry of the Tieluping silver-lead deposit, Henan, China: a case study of orogenic silver-dominated deposits and related tectonic setting

Miner. Deposita

(2004)

W. Chen

Lead isotope study of Xiongershan gold deposit and silver (lead) deposit in western Henan

J. Prec. Metal. Geol.

(1995)

R.N. Clayton et al.

Oxygen isotope exchange between quartz and water

J. Geophys. Res.

(1972)

P.L.F. Collins

Gas hydrates in CO₂-bearing fluid inclusions and use freezing data for estimation of salinity

Econ. Geol.

(1979)

L.W. Diamond

Fluid inclusion evidence for P-V-T-X evolution of hydrothermal solutions in late-Alpine gold-quartz veins at Brusson, Val d'Ayas, northwest Italia

Am. J. Sci.

(1990)

K.A. Evans et al.

Rock-buffering of auriferous fluids in altered rocks associated with the Golden Mile-style mineralization, Kalgoorlie gold field, Western Australia

Econ. Geol.

(2006)

Fan, H.R., Xie, Y.H., Wang, Y.L., Zhao, R., 1994a. Geological-geochemical characteristics and genesis of the Kangshan...

H.R. Fan et al.

Stable isotope geochemistry of rocks and gold deposits in the Xiongershan area western Henan Province

Contrib. Geol. Miner. Resour. Res.

(1994)

H.R. Fan et al.

Ore-forming fluids associated with granite-hosted gold mineralization at the Sanshandao deposit, Jiaodong gold province, China

Miner. Deposita

(2003)

I. Friedman et al.

Data of geochemistry: Compilation of stable isotope fractionation factors of geochemical interest

(1977)

J.J. Gao et al.

Vein structure analysis and ⁴⁰Ar/³⁹Ar dating of sericite from sub–ore altered rocks in the Tieluping large size Ag-Pb deposit of western Henan Province

Acta Geol. Sin.

(2011)

X.Y. Gao et al.

Late Mesozoic magmatism and tectonic evolution in the Southern margin of the North China craton

Sci. China Ser. D: Earth Sci.

(2017)

D.I. Groves et al.

A holistic model for the origin of orogenic gold deposits and its implications for exploration

Miner. Deposita

(2020)

B. Guo et al.

Zircon U-Pb age and Hf isotope composition of the Huashan and Heyu granite plutons at the southern margin of North China Craton: implications for geodynamic setting

Acta Petrol. Sin.

(2009)

Y.G. Han et al.

Single grain Rb-Sr dating of euhedral and cataclastic pyrite from the Qiyugou gold deposit in western Henan, central China

Chin. Sci. Bull.

(2007)

J. Hoefs

Stable Isotope Geochemistry

(2009)

H.X. Hou et al.

The chronology, geochemical characteristics and geological significance of the Mesozoic Shiyaogou hidden granite at the eastern Qinling

Earth Sci.

(2016)

G.H. Hu et al.

Meso-Neoproterozoic sedimentary formation in the southern margin of the North China Craton and its geological implications

Acta Petrol. Sin.

(2013)

S.X. Hu et al.

Geology and metallogeny of the collision belt between the North and the South China plates

(1988)

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2022, Ore Geology Reviews
Citation Excerpt :
Sulfides usually contain extremely low U and Th contents and hence very low radiogenic Pb (Carr et al., 1995; Muchez et al., 2005; Gao et al., 2018). Hence, the Pb isotopic compositions can be used to constrain the sources of ore-forming materials and Pb within mineral deposits (Zhang et al., 2020; Xu et al., 2021). Previous research has suggested that Pb in hydrothermal fluids is derived from mantle, crustal, or mixed mantle and crustal sources (Zartman and Doe, 1981), with variations in the proportions of Pb from these sources controlling the Pb isotopic compositions of different Pb-Zn deposits.
This paper investigates the origin of the newly discovered Devonian carbonate-hosted Banbianjie Ge-Zn deposit in South China. This deposit is rich in Ge (>900 t @ 110 ppm Ge) and contains 7.7 Mt of sulfide ores at a mean grade of 5.1 wt% Zn. The mineralization is stratabound or veined and is structurally controlled by the E-W trending Huangsi fault. Sulfide ores are dominated by sphalerite and dolomite with subsidiary pyrite, marcasite, and calcite, and minor galena. The mineralization forms massive, veined, brecciated, and disseminated structures and the hydrothermal minerals present in the deposit have colloform, fibrous, granular, and acicular textures. The hydrothermal dolomite has positive Ce (δCe = 1.13–1.20) and negative Eu (δEu = 0.43–0.68) anomalies that are indicative of formation in a weakly acidic, reduced, and low-temperature environment. The δ¹³C_PDB and δ¹⁸O_SMOW values of the dolomite range from −0.97‰ to −0.24‰ and +13.89‰ to +21.84‰, respectively, indicating that the dissolution of carbonate wall rocks was involved in the formation of hydrothermal dolomite. Theoretical C-O isotopic calculations further suggest that the hydrothermal dolomite formed as a result of water/rock (W/R) interaction and CO₂ degassing. The δ³⁴S values of the sulfides (−11.23‰ to −4.95‰) are markedly lower than those of the Devonian seawater sulfate and sulfate from evaporates in the Devonian strata (+21.9‰ to +25.9‰), suggesting that the reduced sulfur was derived from evaporates within the ore-hosting sedimentary rocks by bacterial sulfate reduction (BSR). The Banbianjie sulfides have an upper crustal Pb isotopic affinity, as demonstrated by their ²⁰⁶Pb/²⁰⁴Pb (18.335–18.343), ²⁰⁷Pb/²⁰⁴Pb (15.725–15.735), and ²⁰⁸Pb/²⁰⁴Pb (38.288–38.326) ratios, suggesting the metals were derived from metamorphosed basement rocks. These data suggest that: i) the Banbianjie deposit formed as a result of a combination of weakly acidic, reduced, and epigenetic low temperature mineralized fluids, trap structures, and favorable lithologies; ii) W/R interaction and CO₂ degassing caused the precipitation of hydrothermal dolomite, whereas mixing of metals and S²⁻ was the main formation mechanism of the sulfides; and iii) the Banbianjie Ge-Zn deposit is a typical Mississippi Valley-type (MVT) deposit.
Geology and C-O-S-Pb isotopes of the Fangyangshan Cu-Pb-Zn deposit in the Baoshan block (SW China): Implications for metal source and ore genesis
2021, Ore Geology Reviews
Citation Excerpt :
Due to the relatively similar geochemical behavior of Pb, Zn and Cu in hydrothermal fluids, Pb isotopes can fingerprint the metal source(s), reveal the nature of Pb reservoir(s), constrain the timing of Pb extraction from its source, and determine the rough tectonic setting for ore formation (Pass et al., 2014; Li et al., 2018a, 2019a; Zhong et al., 2018). Sulfides usually contain extremely low U and Th contents and little radiogenic Pb isotopes (Gao et al., 2018b; Zhang et al., 2020a, 2020b), such that their measured Pb isotope ratios commonly approximate those of their hydrothermal fluids, and can be used to constrain the fluid Pb source (Liu et al., 2020c; Xu et al., 2021). From the Pb–Pb isotope plots (Fig. 9), the Pb isotope ratios from the different sulfide types of the Fangyangshan Stage I to II are relatively consistent, and display a well-defined, linearly positive 207Pb/204Pb vs. 206Pb/204Pb and 208Pb/204Pb vs. 206Pb/204Pb correlations, which may be considered to reflect mixing of two lead sources (e.g., Mirnejad et al., 2011; Deng et al., 2014c; Lee et al., 2019).
The Fangyangshan deposit is the first Cu-rich Pb-Zn deposit discovered in the Baoshan block (SW China), the northern continuation of the Sibumasu terrane in mainland SE Asia. The stratabound veined/lensoidal orebodies are hosted in the carbonates and calcareous slates of the Upper Cambrian Shahechang Formation. Based on mineral paragenesis and crosscutting vein relationships, three main mineralization stages (pre-ore (I), syn-ore (II-1 to II-3), and post-ore (III)) were identified at Fangyangshan. Metallic minerals include mainly pyrite, chalcopyrite, sphalerite, and galena, whilst non-metallic minerals include mainly quartz and carbonates (calcite and dolomite). The carbonate δ¹³C_V-PDB and δ¹⁸O_V-SMOW values vary from the early syn-ore (II-1: −3.67 to −3.57‰, 8.18–8.92‰), middle syn-ore (II-2: −5.88 to −5.26‰, 8.18–10.79‰), late syn-ore (II-3: −2.79 to −2.37‰, 9.97–11.42‰), to post-ore (−3.75‰, 12.79‰) stage. These C-O isotope data suggest that the early ore-forming fluids were predominantly derived from a magmatic source, and the fluids have increasing sedimentary input via wallrock carbonate dissolution. The stages I to II sulfides have consistently high δ³⁴S values (8.24–14.91‰, avg. 11.51‰), which lie between the magmatic- and evaporite-derived δ³⁴S fields, resembling some typical magmatic-related skarn deposits (e.g., Luziyuan, Jinchanghe, Hetaoping and Heiniuwa) in the Baoshan block. This indicates that the Fangyangshan ore sulfur may have been derived from mixture of magmatic-hydrothermal fluids and seawater sulfates (e.g., gypsum) from the local carbonate-evaporite sequences via thermochemical sulfate reduction (TSR). The Fangyangshan sulfides show a clearly linear positive correlation and an upper crustal affinity for their ²⁰⁶Pb/²⁰⁴Pb (18.2984–19.0819), ²⁰⁷Pb/²⁰⁴Pb (15.7731–15.8107), and ²⁰⁸Pb/²⁰⁴Pb (38.6550–39.3092) ratios, which is again similar to many magmatic-related Pb-Zn deposits within the Baoshan block and near the Sino-Burmese border. This also implies a common mixed source of deeper magmatic fluid and upper continental crust for the lead (and also probably other ore metals) in the regional Pb-Zn ore formation. Considering the regional tectono-metallogenic setting, we propose that the Fangyangshan Cu-Pb-Zn mineralization most probably shared a single magmatic-hydrothermal system with the nearby giant Luziyuan distal skarn deposit. These deposits have many similarities with the high-temperature carbonate replacement deposits (CRDs) elsewhere.

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Genesis of the Kangshan Au-polymetallic deposit, Xiong’ershan District, North China Craton: Constraints from fluid inclusions and C-H-O-S-Pb isotopes

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Regional geology

Strata

Structures

Samples

Petrography

Source and evolution of the ore-forming fluids

Conclusions

Declaration of Competing Interest

Acknowledgements

Int. J. Mass Spectrum.

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Geosci. Front.

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