# Genesis of the Daping Gold Deposit in the Middle Xuefeng Mountain Area, Southern China: Constraints from Geochemistry, Fluid Inclusion, and H-O-S Isotope

Authors: Xu Kong; Wen-Tian Mi; Xue-Yuan Qi; Shu-Jun Lǚ; Yu-Jun Dong; Jie Xin
Journal: Geofluids
 (2022)

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## Abstract

The medium-sized Daping gold deposit is located in the middle Xuefeng Mountain area of Southern China with gold ores hosted in sericite phyllite, sericitolite, and mylonite. The auriferous quartz-carbonate-sulfide veins and adjacent alteration rocks are structurally controlled within the NE (northeast) shear zone with NE, NNE (north-east-east), and NW (northwest) trending at high inclination angles. The petrogeochemistry analysis results show that the gold ores are characterized by high content values of SiO2, S, and As and low content values of Al2O3 and Na2O and display strong enrichment of LREE with δEu values ranging from 0.54 to 0.75. Four stages of mineralization/alteration were identified: the first stage has mineral assemblages of quartz+pyrite+arsenopyrite±carbonate minerals, the second stage has mineral assemblages of quartz+polymetallic sulfide minerals (pyrite, arsenopyrite, chalcocite, galena, chalcopyrite, tetrahedrite)±chlorite±carbonate minerals, the third stage has mineral assemblages of quartz and carbonate minerals, and the supergene stage is characterized by limonite±patina which were formed by the oxidation of metal sulfides. Among them, the first stage and the second stage are the main gold mineralization stages. The ore-forming fluid inclusions in quartz are mainly composed of liquid phase (H2O) and gas phase (H2O and CO2), and based on the microthermometric analysis, the first metallogenic stage and second metallogenic stage yielded average homogenization temperature of 184.5 and 255.8°C and average salinity of 7.64 wt.% NaCl eqv. and 11.35 wt.% NaCl eqv., respectively. Thus, the ore-forming fluids belong to H2O-CO2-NaCl, medium-low temperature, and medium-low salinity fluid. The δDH2O and δ18OH2O values of auriferous quartz are from -51‰ to 62‰ and from -1.44‰ to 5.42‰, respectively, indicating that the ore-forming fluids may belong to mixing fluids of the magmatic fluid and meteoric hydrothermal fluid. The values of δ34S of metal sulfides range from -0.94‰ to 1.98‰ (-0.131‰ in average), implying that sulfur may source from the concealed granite and/or basement metamorphic strata. The Daping gold deposit formed in the Indosinian period under the tectonic environment of compression between the Cathaysian plate and Yangtze plate and may belong to orogenic gold deposits.


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## Body

## 1. Introduction

As one of the crucial gold producers of south China, the Jiangnan Orogen Belt (JOB) has a total gold reserve of >970 tons [1] and thus attracted more and more attention from the metallogeny geologists. The middle Xuefeng Mountain which belongs to the western section of the Jiangnan Orogen is located in the transitional region between the Cathaysia plate and the Yangtze plate (Figure 1(a)) [1–8]. At present, 21 gold deposits (points) have been discovered, and among them, the Chanziping gold deposit [9–13] and the Daping gold deposit [14] have a scale of large size and medium size, respectively. The exploration of the Daping gold deposit began in 1987 [15] and has proved gold reserves of more than 10 tons. Previous studies on the geological characteristics and metallogenic chronology indicate that the Daping gold deposit belongs to the shear zone type [16, 17] with ore-forming age of 204.8 Ma which belongs to Indosinian [18]. However, the ore-forming fluids, geochemical characteristics of the main and trace elements, rare earth elements, and isotopes of the deposit have not been systematically studied, and its metallogenic mechanism and process are still unknown.Figure 1
(a) Major tectonic blocks of China. (b) Regional geological sketch map of the middle Xuefeng Mountain (modified after [6–8]): 1: Quaternary (Q); 2: Palaeogene (E); 3: Ordovician (O); 4: Cambrian (Є); 5: Sinian and Nanhuan (Z+Nh); 6: Gaojian Group (QbG); 7: Early Triassic granite rocks; 8: Mafic-ultramafic rocks; 9: shear zone; 10: auriferous vein; 11: gold occurring spot; 12: study area.This paper attempts to reveal the source of metallogenic materials, metallogenic mechanism, and deposit type of the Daping gold deposit by petrogeochemistry, H-O-S isotopes, and ore-forming fluids and provide more metallogenic information for further exploration and prediction of the Daping gold deposit and other similar gold deposits with the same metallogenic characteristics.


## 2. Regional Geological Setting

Daping gold deposit which is located in the transitional zone between Yangtze plate and Cathaysia plate belongs to the middle Xuefeng metallogenic belt (Figure1(a)). The regional strata are composed of Quaternary, Palaeogene, Ordovician, Cambrian, Sinian, Nanhua System, and Gaojian Group of Qingbaikou System (Figure 1(b)). Among these strata, the Gaojian Group of the Qingbaikou System and the Nanhua Systems which belong to low-grade metamorphic greenschist facies clastic rocks with high gold-bearing background values are the main ore-bearing strata in the gold metallogenic belt of the middle Xuefeng Mountain [19]. Frequent acid magmatic activities occurred in this area during the Indosinian period (e.g., Zhonghuashan granite and Huangmaoyuan granite, Figure 1(b)). In addition, six NE-trending or NNE-trending ductile shear zones cross the middle Xuefeng Mountain gold field with length of 10–25 km and width of 0.5–2 km.


## 3. Geological Characteristics of Daping Gold Deposit

### 3.1. Deposit Features

The stratum of the Daping gold deposit is composed of the Gaojian Group of the Qingbaikou System and Changan Formation of the Nanhua System, and the gold-bearing faults are NE-trending, NW-trending [20, 21], and NNE-trending. Crossing through the middle part of the study area (Figure 2), the NE-trending ductile-brittle shear cleavage zone may serve as the ore-forming fluid passageways as well as auriferous host structures.Figure 2
Geological sketch map of the Daping gold deposit (modified after [59]): 1: unconformity boundary; 2: conformity boundary; 3: Changan Formation (Nhc); 4: Yanmenzhai Formation (Qbym); 5: Jiajiantian Formation (Qbj); 6: Zhuanqiangwan Formation (Qbz); 7: ductile-brittle shear zone; 8: auriferous vein; 9: sample location; 10: prospecting line. Due to all the samples coming from diamond drills, only the horizontal positions are shown.


### 3.2. The Orebody Characteristics

At present, 23 auriferous veins were found out with a length of 120–2100 m and a width of 1.30–70 m. The auriferous veins which occurred in the ductile shear zone or adjacent fault segments are NW-trending of I6, I7, I9, I12, and I19 or NE-NNE-trending of I17, I20, I21, and I26. The NW-trending veins intersect the NE-trending vein at a large angle, and both the NE-trending and NW-trending auriferous veins have inclination angles of above 70° (Figure 3). At present, 38 ore bodies have been found out between the elevation of -40 m and 340 m, and among them, 7 main ore bodies have lengths of 170–470 m with an average thickness of 1.36–4.85 m and an average grade of 1.63–25.80 ppm. The alteration types of the Daping gold ores include silicification, sericitization, chloritization, carbonization, and clayization (Figures 4(a), 4(c), and 4(h)). The intensity of silicification, pyritization, and sericitization has positive relations with the intensity of gold mineralization.Figure 3
Geologic cross-section (prospecting line 135) of the Daping gold deposit (modified after [59]).Figure 4
Photomicrographs and microstructures of the Daping gold deposit. (a) The schistose foliation formed by the orientation of sericite (cross-polarized light). (b) Tensile ductile deformation of the phyllite breccia (cross-polarized light). (c) The silicification belt around the quartz vein (plane-polarized light). (d) The pressure shadow (recrystallized quartz) formed by the arsenopyrite (cross-polarized light). (e) The quartz vein containing hypidiomorphic pyrite and xenomorphic arsenopyrite of the first stage of the metallogenic period (reflected light). (f) The quartz vein containing mineral assemblages of xenomorphic arsenopyrite, chalcopyrite, and tetrahedrite of the second stage of the metallogenic period (reflected light). (g) The quartz-carbonate vein of the third stage of the metallogenic period (cross-polarized light). Mineral abbreviation: Py: pyrite; Ars: arsenopyrite; Cc: chalcocite; Gn: galena; Ccp: chalcopyrite; Thr: tetrahedrite; Q: quartz; Ser: sericite; Ab: albite; Cb: carbonate mineral; Op: opaque mineral.
(a)(b)(c)(d)(e)(f)(g)(h)


### 3.3. Ore Characteristics

According to the differences of gold-bearing structures, the Daping gold ores can be divided into quartz vein type (gold mineralization mainly occurred in quartz veins and nearby metal sulfides), altered rock type (gold mineralization mainly occurred in alteration rocks), and tectonic breccia type (gold mineralization mainly occurred in tectonic breccia rocks) (Figure5). The metal minerals of ores are composed of pyrite, arsenopyrite, chalcopyrite, galena, sphalerite, and stibnite, and among them, pyrite and arsenopyrite are the main gold-bearing minerals. The gangue minerals are mainly including quartz, carbonate minerals, albite, sericite, and muscovite.Figure 5
Macroscopic images of auriferous veins and deformation characteristics of the Daping gold deposit. (a) Field image of the NW-trending veins of I12. (b) Macroscopic image of the NE-trending veins of I17 shows distinct features of sinistral shear deformation. (c) Irregular quartz breccia and sericite slate breccia of I21 vein formed in the tectonic shearing environment. (d) The schistose foliation formed by the orientation of the sericite shows ductile deformation in the I21. (e) The tensile-shearing space was filled by carbonate veins. (f) Quartz-carbonate veins show undulating edge of ductile deformation.
(a)(b)(c)(d)(e)(f)According to the mineral assemblages, the metallogenic process of the Daping gold deposit can be divided into two periods (metallogenic period and supergene period) and four stages (Table1, Figure 4). The first stage has mineral assemblages of quartz+pyrite+arsenopyrite±carbonate minerals and the second stage has mineral assemblages of quartz+polymetallic sulfide minerals (pyrite, arsenopyrite, chalcocite, galena, chalcopyrite, tetrahedrite)±chlorite±carbonate minerals which are the main gold mineralization stages. The third stage has mineral assemblages of quartz and carbonate minerals. The supergene stage is characterized by the mineral of limonite±patina which is formed by the oxidation of metal sulfides.Table 1
Mineral assemblages of ore-forming stages and characteristics of the fluid inclusions.
PeriodStageMineral assemblagesSample No.Type of the fluid inclusionsSize of the fluid inclusions (μm)Composition of liquid phaseComposition of gas phaseV/T (%) (20°C)Metallogenic periodThe first stageQ+Py+Ars±CbH28-S1, H43-S1Two-phase+liquid phase4.1–12.5H2OH2O14–28The second stageQ+polymetallic sulfide minerals (Py, Ars, Cc, Gn, Ccp, Thr)±Chl±CbH10-S2, H21-S2, H28-S2, H43-S2Two-phase+liquid phase+gas phase2.5–17.8H2OH2O, CO27–45The third stageQ+CbH7-S3, H10-S3Two-phase+gas phase2.8–5.1H2OH2O, CO25–20Supergene periodSupergene stageLimonite±patinaNotes: Py: pyrite; Ars: arsenopyrite; Cc: chalcocite; Gn: galena; Ccp: chalcopyrite; Thr: tetrahedrite; Q: quartz; Chl: chlorite; Cb: carbonate minerals;V/T: vapor/total ratio of two-phase inclusions.


## 3.1. Deposit Features

The stratum of the Daping gold deposit is composed of the Gaojian Group of the Qingbaikou System and Changan Formation of the Nanhua System, and the gold-bearing faults are NE-trending, NW-trending [20, 21], and NNE-trending. Crossing through the middle part of the study area (Figure 2), the NE-trending ductile-brittle shear cleavage zone may serve as the ore-forming fluid passageways as well as auriferous host structures.Figure 2
Geological sketch map of the Daping gold deposit (modified after [59]): 1: unconformity boundary; 2: conformity boundary; 3: Changan Formation (Nhc); 4: Yanmenzhai Formation (Qbym); 5: Jiajiantian Formation (Qbj); 6: Zhuanqiangwan Formation (Qbz); 7: ductile-brittle shear zone; 8: auriferous vein; 9: sample location; 10: prospecting line. Due to all the samples coming from diamond drills, only the horizontal positions are shown.


## 3.2. The Orebody Characteristics

At present, 23 auriferous veins were found out with a length of 120–2100 m and a width of 1.30–70 m. The auriferous veins which occurred in the ductile shear zone or adjacent fault segments are NW-trending of I6, I7, I9, I12, and I19 or NE-NNE-trending of I17, I20, I21, and I26. The NW-trending veins intersect the NE-trending vein at a large angle, and both the NE-trending and NW-trending auriferous veins have inclination angles of above 70° (Figure 3). At present, 38 ore bodies have been found out between the elevation of -40 m and 340 m, and among them, 7 main ore bodies have lengths of 170–470 m with an average thickness of 1.36–4.85 m and an average grade of 1.63–25.80 ppm. The alteration types of the Daping gold ores include silicification, sericitization, chloritization, carbonization, and clayization (Figures 4(a), 4(c), and 4(h)). The intensity of silicification, pyritization, and sericitization has positive relations with the intensity of gold mineralization.Figure 3
Geologic cross-section (prospecting line 135) of the Daping gold deposit (modified after [59]).Figure 4
Photomicrographs and microstructures of the Daping gold deposit. (a) The schistose foliation formed by the orientation of sericite (cross-polarized light). (b) Tensile ductile deformation of the phyllite breccia (cross-polarized light). (c) The silicification belt around the quartz vein (plane-polarized light). (d) The pressure shadow (recrystallized quartz) formed by the arsenopyrite (cross-polarized light). (e) The quartz vein containing hypidiomorphic pyrite and xenomorphic arsenopyrite of the first stage of the metallogenic period (reflected light). (f) The quartz vein containing mineral assemblages of xenomorphic arsenopyrite, chalcopyrite, and tetrahedrite of the second stage of the metallogenic period (reflected light). (g) The quartz-carbonate vein of the third stage of the metallogenic period (cross-polarized light). Mineral abbreviation: Py: pyrite; Ars: arsenopyrite; Cc: chalcocite; Gn: galena; Ccp: chalcopyrite; Thr: tetrahedrite; Q: quartz; Ser: sericite; Ab: albite; Cb: carbonate mineral; Op: opaque mineral.
(a)(b)(c)(d)(e)(f)(g)(h)


## 3.3. Ore Characteristics

According to the differences of gold-bearing structures, the Daping gold ores can be divided into quartz vein type (gold mineralization mainly occurred in quartz veins and nearby metal sulfides), altered rock type (gold mineralization mainly occurred in alteration rocks), and tectonic breccia type (gold mineralization mainly occurred in tectonic breccia rocks) (Figure5). The metal minerals of ores are composed of pyrite, arsenopyrite, chalcopyrite, galena, sphalerite, and stibnite, and among them, pyrite and arsenopyrite are the main gold-bearing minerals. The gangue minerals are mainly including quartz, carbonate minerals, albite, sericite, and muscovite.Figure 5
Macroscopic images of auriferous veins and deformation characteristics of the Daping gold deposit. (a) Field image of the NW-trending veins of I12. (b) Macroscopic image of the NE-trending veins of I17 shows distinct features of sinistral shear deformation. (c) Irregular quartz breccia and sericite slate breccia of I21 vein formed in the tectonic shearing environment. (d) The schistose foliation formed by the orientation of the sericite shows ductile deformation in the I21. (e) The tensile-shearing space was filled by carbonate veins. (f) Quartz-carbonate veins show undulating edge of ductile deformation.
(a)(b)(c)(d)(e)(f)According to the mineral assemblages, the metallogenic process of the Daping gold deposit can be divided into two periods (metallogenic period and supergene period) and four stages (Table1, Figure 4). The first stage has mineral assemblages of quartz+pyrite+arsenopyrite±carbonate minerals and the second stage has mineral assemblages of quartz+polymetallic sulfide minerals (pyrite, arsenopyrite, chalcocite, galena, chalcopyrite, tetrahedrite)±chlorite±carbonate minerals which are the main gold mineralization stages. The third stage has mineral assemblages of quartz and carbonate minerals. The supergene stage is characterized by the mineral of limonite±patina which is formed by the oxidation of metal sulfides.Table 1
Mineral assemblages of ore-forming stages and characteristics of the fluid inclusions.
PeriodStageMineral assemblagesSample No.Type of the fluid inclusionsSize of the fluid inclusions (μm)Composition of liquid phaseComposition of gas phaseV/T (%) (20°C)Metallogenic periodThe first stageQ+Py+Ars±CbH28-S1, H43-S1Two-phase+liquid phase4.1–12.5H2OH2O14–28The second stageQ+polymetallic sulfide minerals (Py, Ars, Cc, Gn, Ccp, Thr)±Chl±CbH10-S2, H21-S2, H28-S2, H43-S2Two-phase+liquid phase+gas phase2.5–17.8H2OH2O, CO27–45The third stageQ+CbH7-S3, H10-S3Two-phase+gas phase2.8–5.1H2OH2O, CO25–20Supergene periodSupergene stageLimonite±patinaNotes: Py: pyrite; Ars: arsenopyrite; Cc: chalcocite; Gn: galena; Ccp: chalcopyrite; Thr: tetrahedrite; Q: quartz; Chl: chlorite; Cb: carbonate minerals;V/T: vapor/total ratio of two-phase inclusions.


## 4. Sampling and Analytical Methods

### 4.1. Samples

The nineteen samples which were collected from drill holes are used for the geochemical and metallogenic study of the Daping gold deposit. Samples H3, H6, H7, and H8 from auriferous vein I6 are sericite phyllite with gold content of 0.26–1.19 ppm. Samples H5, H40, H52, H43, H46, H62, and H84 from auriferous vein I17 are sericite phyllite with gold content of 0.61–2.94 ppm. Samples H28, H34, H51, H22, H10, H16, H26, and H9 from auriferous vein I21 are sericite phyllite, sericitolite, and mylonite with gold content of 1.47–10.77 ppm. For detailed sample information, see Table 2 and Figure 2.Table 2
Detail location and descriptions of the samples of the Daping gold deposit. The thickness and content of gold of the samples are from [59].
SampleAuriferous veinSampling locationThickness (m)Content of gold (ppm)Rock nameH3I6ZK3201 drilling core 198 m1.071.19Sericite phylliteH6I6ZK2802 drilling core 210 m0.890.84Sericite phylliteH7I6ZK2802 drilling core 212 m0.901.45Sericite phylliteH8I6ZK2802 drilling core 214 m1.020.26Sericite phylliteH5I17ZK11701 drilling core 86 m1.071.39Sericite phylliteH40I17ZK11701 drilling core 191 m0.942.94Sericite phylliteH52I17ZK11701 drilling core 222 m0.891.16Sericite phylliteH43I17ZK12101 drilling core 211 m1.161.11Sericite phylliteH46I17ZK12101 drilling core 232 m1.311.21Sericite phylliteH62I17ZK12501 drilling core 232 m0.841.13Sericite phylliteH84I17ZK12501 drilling core 414 m0.990.61Sericite phylliteH28I21ZK13301 drilling core 238 m1.106.78SericitoliteH34I21ZK13301 drilling core 248 m0.8510.77SericitoliteH51I21ZK13301 drilling core 290 m1.161.86Sericite phylliteH22I21ZK13501 drilling core 144 m1.003.28Sericite phylliteH10I21ZK13901 drilling core 138 m1.358.21MyloniteH16I21ZK13901 drilling core 152 m1.181.47Sericite phylliteH26I21ZK13902 drilling core 324 m0.905.95Sericite phylliteH9I21ZK14101 drilling core 211 m1.082.93Sericite phyllite


### 4.2. Analytical Methods

The major elements and trace element of whole rock were tested in samples H3, H5, H6, H7, H8, H26, H28, H34, H40, H43, H46, H51, H52, H62, and H84. Hydrogen and oxygen isotopes of mineral quartz were tested in samples H28, H34, H22, H10, H16, H26, H9, and H46. Sulfur isotope of arsenopyrite and pyrite was tested in samples H34, H22, H16, H26, H7, and H46. The homogenization temperature, freezing temperature, and laser Raman spectra of the ore-forming fluid inclusions were tested in samples H7, H10, H21, H28, and H43.The major elements, trace element, and isotopes of sulfur, hydrogen, and oxygen of the Daping gold ore samples were measured in the Australian Real Analysis Test (Guangzhou) Co., Ltd. The major elements were tested by the X-ray fluorescence instrument of ME-XRF26d with precision and accuracy better than ±5%. The trace elements and the rare earth elements are measured by instruments of M61-MS81, and the relative error is less than 10%. Sulfur isotope was measured by an instrument of S-ISTP01L with accuracy of better than 0.02%. Hydrogen isotope was tested by the instrument of H-ISTP01 with accuracy of better than 0.3%. The oxygen isotope was measured by the instrument of O-ISTP01 with accuracy of better than 0.03%.δ18OH2O were calculated according to the equation suggested by Clayton et al. [22]: δ18OQ–δ18OH2O≈3.38×106/T2−3.40.The homogenization temperature and freezing temperature testing of the ore-forming fluids were conducted by the instrument of LINKAMTHMSG600 in the Fluid Inclusion Laboratory of Chengdu University of Technology with temperature accuracy of ±0.1°C. The salinities of the metallogenic fluid inclusions were calculated by using the equation of [23]: W=0.00+1.78Tm−0.042Tm2+0.000557Tm3, where W is the weight percentage of NaCl (0–23.3% NaCl) and Tm is the freezing point depression (°C). The laser Raman spectra of single fluid inclusion were measured by the instrument of HORIBA LabRAM HR Evolution in the Raman Lab of Chengdu University of Technology with spatial resolution of 1 μm.


## 4.1. Samples

The nineteen samples which were collected from drill holes are used for the geochemical and metallogenic study of the Daping gold deposit. Samples H3, H6, H7, and H8 from auriferous vein I6 are sericite phyllite with gold content of 0.26–1.19 ppm. Samples H5, H40, H52, H43, H46, H62, and H84 from auriferous vein I17 are sericite phyllite with gold content of 0.61–2.94 ppm. Samples H28, H34, H51, H22, H10, H16, H26, and H9 from auriferous vein I21 are sericite phyllite, sericitolite, and mylonite with gold content of 1.47–10.77 ppm. For detailed sample information, see Table 2 and Figure 2.Table 2
Detail location and descriptions of the samples of the Daping gold deposit. The thickness and content of gold of the samples are from [59].
SampleAuriferous veinSampling locationThickness (m)Content of gold (ppm)Rock nameH3I6ZK3201 drilling core 198 m1.071.19Sericite phylliteH6I6ZK2802 drilling core 210 m0.890.84Sericite phylliteH7I6ZK2802 drilling core 212 m0.901.45Sericite phylliteH8I6ZK2802 drilling core 214 m1.020.26Sericite phylliteH5I17ZK11701 drilling core 86 m1.071.39Sericite phylliteH40I17ZK11701 drilling core 191 m0.942.94Sericite phylliteH52I17ZK11701 drilling core 222 m0.891.16Sericite phylliteH43I17ZK12101 drilling core 211 m1.161.11Sericite phylliteH46I17ZK12101 drilling core 232 m1.311.21Sericite phylliteH62I17ZK12501 drilling core 232 m0.841.13Sericite phylliteH84I17ZK12501 drilling core 414 m0.990.61Sericite phylliteH28I21ZK13301 drilling core 238 m1.106.78SericitoliteH34I21ZK13301 drilling core 248 m0.8510.77SericitoliteH51I21ZK13301 drilling core 290 m1.161.86Sericite phylliteH22I21ZK13501 drilling core 144 m1.003.28Sericite phylliteH10I21ZK13901 drilling core 138 m1.358.21MyloniteH16I21ZK13901 drilling core 152 m1.181.47Sericite phylliteH26I21ZK13902 drilling core 324 m0.905.95Sericite phylliteH9I21ZK14101 drilling core 211 m1.082.93Sericite phyllite


## 4.2. Analytical Methods

The major elements and trace element of whole rock were tested in samples H3, H5, H6, H7, H8, H26, H28, H34, H40, H43, H46, H51, H52, H62, and H84. Hydrogen and oxygen isotopes of mineral quartz were tested in samples H28, H34, H22, H10, H16, H26, H9, and H46. Sulfur isotope of arsenopyrite and pyrite was tested in samples H34, H22, H16, H26, H7, and H46. The homogenization temperature, freezing temperature, and laser Raman spectra of the ore-forming fluid inclusions were tested in samples H7, H10, H21, H28, and H43.The major elements, trace element, and isotopes of sulfur, hydrogen, and oxygen of the Daping gold ore samples were measured in the Australian Real Analysis Test (Guangzhou) Co., Ltd. The major elements were tested by the X-ray fluorescence instrument of ME-XRF26d with precision and accuracy better than ±5%. The trace elements and the rare earth elements are measured by instruments of M61-MS81, and the relative error is less than 10%. Sulfur isotope was measured by an instrument of S-ISTP01L with accuracy of better than 0.02%. Hydrogen isotope was tested by the instrument of H-ISTP01 with accuracy of better than 0.3%. The oxygen isotope was measured by the instrument of O-ISTP01 with accuracy of better than 0.03%.δ18OH2O were calculated according to the equation suggested by Clayton et al. [22]: δ18OQ–δ18OH2O≈3.38×106/T2−3.40.The homogenization temperature and freezing temperature testing of the ore-forming fluids were conducted by the instrument of LINKAMTHMSG600 in the Fluid Inclusion Laboratory of Chengdu University of Technology with temperature accuracy of ±0.1°C. The salinities of the metallogenic fluid inclusions were calculated by using the equation of [23]: W=0.00+1.78Tm−0.042Tm2+0.000557Tm3, where W is the weight percentage of NaCl (0–23.3% NaCl) and Tm is the freezing point depression (°C). The laser Raman spectra of single fluid inclusion were measured by the instrument of HORIBA LabRAM HR Evolution in the Raman Lab of Chengdu University of Technology with spatial resolution of 1 μm.


## 5. Analytical Results

### 5.1. Major Elements

The test results of the major elements illustrate that the Daping gold ores have a high content of SiO2 and S and low content of Al2O3, TiO2, CaO, Na2O, MnO, and K2O (Table 3). With the increasing of gold mineralization, the intensity of silicification alteration and sulfide mineralization increased significantly.Table 3
Average content of the major elements of the Daping gold deposit (wt.%).
SampleSiO2Al2O3TFe2O3CaOMgOK2ONa2OTiO2P2O5MnOSO3LOITotalH375.6711.653.621.490.972.591.500.360.070.083.170.87102.04H573.1113.142.321.220.601.444.780.330.040.050.232.4199.67H667.5612.614.833.171.823.930.120.410.140.213.812.58101.19H767.4513.315.942.001.372.073.620.400.090.145.921.33103.64H869.5813.983.721.061.063.401.800.470.080.100.813.4699.52H2671.6810.236.301.861.312.610.870.400.030.093.540.9699.88H2876.507.865.761.640.911.820.990.290.120.063.900.94100.79H3467.9812.097.880.880.962.861.500.470.050.065.460.55100.74H4070.6112.625.241.320.862.931.750.500.090.074.420.53100.94H4365.8917.064.731.241.144.182.230.650.140.121.171.86100.41H4666.4914.544.512.901.783.561.320.570.130.122.062.22100.2H5164.7915.535.861.771.573.681.760.660.080.121.431.8199.06H5265.3613.174.693.821.903.461.280.410.090.231.803.6499.85H6265.7514.324.313.411.803.851.220.500.080.191.123.46100.01H8460.9318.184.772.991.594.661.300.680.080.142.612.81100.74Average68.6213.354.972.051.313.141.740.470.090.122.761.96


### 5.2. Trace Element

The trace element analysis results (Table4) show that the samples have wU/wTh ratios of 0.18–0.24 (0.20 in average), wRb/wSr ratios of 0.35–1.15 (0.68 in average), wCo/wNi ratios of 0.45–0.93 (0.68 in average), and wZr/wHf ratios of 32.50–34.26 (33.47 in average). The content values of U, Rb, and Co in the ores of Daping gold deposit are smaller than Th, Sr, and Ni. The content value of Zr is greater than Hf. The original mantle-standardized spider map shows that the elements of Li, Cr, Ni, Zn, Rb, Th, and Sr enriched obviously, and on the contrary, the elements of Sc, Co, Cu, Ga, Cs, Tl, and Zr were depleted (Figure 6).Table 4
Content of trace elements of the Daping gold deposit (ppm).
SampleH3H5H6H7H8H26H28H34H40H43H46H51H52H62H84AverageLi20.407.2014.609.5012.406.106.406.006.309.4013.4010.506.609.4011.109.95Sc8.009.709.4010.1011.008.606.009.3010.7014.1011.8014.609.9010.5013.5010.48V27.0017.0030.0028.0056.0050.0036.0057.0051.0068.0059.0077.0036.0050.0069.0047.40Cr35.008.0021.0024.0035.0031.0034.0033.0025.0025.0032.0040.0013.0018.0026.0026.67Co4.803.105.408.2010.808.307.607.708.509.309.3011.205.607.108.807.71Ni10.603.9011.4016.7014.0012.3011.7013.0010.6011.4017.7017.206.008.7010.8011.73Cu7.005.302.607.7022.4016.009.307.1014.6025.9015.2019.708.6011.7012.8012.39Zn25.0057.0015.0016.0022.0049.0031.0024.0017.0022.0020.0066.0018.0017.0021.0028.00Ga16.9013.6517.8516.1020.6014.5510.2015.0516.4021.2018.2520.4017.5517.6023.9017.35Rb88.4049.40121.5069.90111.5090.6060.6093.7097.10128.50113.50124.00111.00118.00148.50101.75Sr102.50165.50121.00143.0097.10211.00175.00142.00128.00136.50194.00204.00163.50200.00190.50158.24Nb9.609.3011.4010.7011.106.604.607.208.0010.709.2010.108.508.9011.509.16Cs15.652.8510.204.706.105.123.385.166.127.868.896.006.646.909.667.02Ta0.620.660.630.610.630.410.250.390.560.630.570.630.530.620.770.57Tl0.410.260.530.320.460.390.260.400.440.570.510.510.480.510.660.45Bi0.200.160.270.680.920.230.290.180.390.250.350.210.160.200.150.31Th6.529.028.017.999.015.574.346.376.999.779.178.877.479.4911.307.99U1.401.971.951.771.980.990.791.171.361.841.721.681.581.952.141.62Zr194.00234.00213.00191.00212.00125.0096.00145.00177.00242.00218.00195.00209.00205.00262.00194.53Hf5.807.206.305.806.503.702.904.405.207.206.405.806.106.007.905.81wU/wTh0.210.220.240.220.220.180.180.180.190.180.190.190.210.210.190.20wRb/wSr0.860.301.000.491.150.430.350.660.760.940.590.610.680.590.780.68wCo/wNi0.450.790.470.490.770.670.650.590.800.820.530.650.930.820.810.68wZr/wHf33.4532.5033.8132.9332.6233.7833.1032.9534.0433.6134.0633.6234.2634.1733.1633.47Figure 6
Primitive standard spider graph of trace elements of Daping gold deposit. The values for primitive mantle are from [62].


### 5.3. Rare Earth Element

Rare earth elements are important indications for the analysis of the ore-forming material sources due to their stable chemical properties and the specificity of distribution [24]. REE testing results (Table 5) show that the total amount of rare earth element (ΣREE) of the Daping gold ores is 98.20–218.76 ppm (160.58 ppm in average), the total amount of LREE is 88.38–192.36 ppm (142.38 ppm in average), the total amount of HREE is 9.82–26.40 ppm (18.20 ppm in average), the ratio of wLREE/wHREE is 6.91–9.00 (7.82 in average), and the ratio of wLaN/wYbN is 6.78–10.20 (7.95 in average). The δEu values ranging from 0.54 to 0.75 and the δCe values ranging from 1.05 to 1.09 show positive Ce anomaly and negative Eu anomaly. All of the samples have a similar REE pattern of right-dip type indicating that they may have homologous origins (Figure 6) [25].Table 5
Content of rare earth elements of the Daping gold deposit (ppm).
SampleH3H5H6H7H8H26H28H34H40H43H46H51H52H62H84AverageLa31.0035.5045.0039.9036.1020.5020.9026.0029.0038.4033.4033.7031.8033.6039.2032.93Ce64.4074.2090.4081.6075.6043.1042.4053.4061.0080.1069.5070.2067.1067.6082.3068.19Pr7.098.069.898.558.054.614.565.836.558.647.577.607.287.158.927.36Nd26.4029.2037.3031.1029.1017.0016.4021.8023.9031.9027.6028.3027.2025.8032.3027.02Sm5.835.947.856.336.343.503.434.544.996.755.965.935.875.336.775.69Eu1.160.961.921.241.300.740.690.961.011.451.291.271.171.151.471.19Gd5.125.067.705.125.853.222.894.004.185.644.915.165.414.875.694.99Tb0.880.781.190.800.920.480.450.630.680.900.770.840.850.780.870.79Dy5.094.876.644.675.602.922.553.644.125.434.825.055.214.585.514.71Ho1.071.061.390.971.150.630.530.750.841.120.991.011.100.961.150.98Er3.273.144.063.013.401.831.482.162.383.252.892.983.142.823.312.87Tm0.490.490.630.480.530.270.230.330.380.500.450.450.470.420.520.44Yb3.283.234.143.223.771.921.472.182.533.402.883.113.212.863.372.97Lu0.470.490.650.520.570.290.220.330.380.500.450.480.480.430.530.45Y33.2029.6042.6029.4033.5018.3015.6021.6024.6031.7029.4030.2031.4028.3033.3028.85ΣREE155.55172.98218.76187.51178.28101.0198.20126.55141.94187.98163.48166.08160.29158.35191.91160.58LREE135.88153.86192.36168.72156.4989.4588.38112.53126.45167.24145.32147.00140.42140.63170.96142.38HREE19.6719.1226.4018.7921.7911.569.8214.0215.4920.7418.1619.0819.8717.7220.9518.20wLREE/wHREE6.918.057.298.987.187.749.008.038.168.068.007.707.077.948.167.82wLaN/wYbN6.787.887.808.896.877.6610.208.558.228.108.327.777.118.438.347.95δEu0.650.540.750.670.650.670.670.690.680.720.730.700.630.690.720.68δCe1.071.081.051.081.091.091.061.061.091.081.071.081.081.071.081.07


### 5.4. Hydrogen and Oxygen Isotope

The hydrogen and oxygen isotope testing results (Table6) of quartz mineral samples show that the value of δDH2O is from -51‰ to 62‰ (-58.6‰ in average), and the value of δ18OH2O is from -1.44‰ to 5.42‰ (1.92‰ in average).Table 6
Isotopic values of D and O of the Daping gold deposit. The values of theδOH2O are yielded by the equation: δ18OQ–δ18OH2O≈3.38×106/T2−3.40 [22].
SampleMineralδD (‰)δOV-SMOW (‰)δOH2O (‰)T (°C)H28-OH1Quartz-6211.42.72255.8H34-OH1Quartz-5914.15.42255.8H22-OH1Quartz-6110.11.42255.8H10-OH1Quartz-6011.3-1.44184.5H16-OH1Quartz-5312.90.16184.5H26-OH1Quartz-62163.26184.5H9-OH1Quartz-6113.60.86184.5H46-OH1Quartz-5115.72.96184.5


### 5.5. Sulfur Isotope

The sulfur isotope is important for studying the source of ore-forming materials [26, 27]. Six sulfur isotope samples of metal sulfides (pyrite or arsenopyrite) were tested, and the testing results (Table 7) show that the value of δ34S is from -1.00‰ to 1.98‰ (-0.13‰ in average), which are close to the average S isotope of the magmatic hydrothermal deposit of 1.68‰ [28, 29].Table 7
Isotope values ofδ34S in the arsenopyrite or pyrite of the Daping gold deposit.
SampleMineralδ34S (‰)H34-S1Arsenopyrite-0.94H22-S1Arsenopyrite-1H16-S1Arsenopyrite-0.76H26-S1Arsenopyrite-0.67H7-S1Pyrite1.98H46-S1Pyrite0.23


### 5.6. Ore-Forming Fluid Inclusion Testing

According to the microscope observation, the ore-forming fluid inclusions are in the shape of circle, ellipse, or irregular. The metallogenic period of the Daping gold deposit can be divided into three stages. The inclusions of stage one are two-phase inclusions and liquid phase inclusions. The inclusions of stage two are two-phase inclusions, liquid phase inclusions, and gas inclusions. The inclusions of stage three are two-phase inclusions and gas phase inclusions. Based on the laser Raman spectra testing, the composition of the liquid phase inclusions is H2O, and the composition of the gas phase inclusions is H2O and CO2. For detailed characteristics of the fluid inclusions, see Table 1 and Figures 7 and 8.Figure 7
Photomicrographs of the typical fluid inclusions of the Daping gold deposit. (a) Two-phase and liquid phase of the first ore-forming stage. (b) Two-phase inclusions of the first ore-forming stage. (c) Two-phase, liquid phase, and gas phase inclusions of the second ore-forming stage. (d) Two-phase and gas phase inclusions of the third ore-forming stage. Abbreviation:LH2O: liquid H2O; GH2O: vapor H2O; GCO2: vapor CO2.
(a)(b)(c)(d)Figure 8
Microstructures and laser Raman spectra for fluid inclusions in Daping gold deposit.
(a)(b)The first stage of the ore-forming fluid yielded homogenization temperature of 218.0–293.1°C (255.8°C in average) and salinity of 4.98–17.94 wt.% NaCl eqv. (11.35 wt.% NaCl eqv. in average). The second stage of the ore-forming fluid yielded homogenization temperature of 159.3–240.6°C (184.5°C in average) and salinity of 5.28–10.59 wt.% NaCl eqv. (7.64 wt.% NaCl eqv. in average). The third stage of the ore-forming fluid yielded homogenization temperature of 138.5–177.1°C (157.3°C in average) and salinity of 0.71–7.78 wt.% NaCl eqv. (4.82 wt.% NaCl eqv. in average). For details of the fluid inclusion testing, see Table8 and Figure 9.Table 8
Microthermometric data of fluid inclusions of the metallogenic period in the Daping gold deposit.
StageHost mineralCountsTh (°C)AverageTh (°C)Tm (ice) (°C)AverageTm (ice) (°C)Salinity (wt.% NaCl eqv.)Average salinity (wt.% NaCl eqv.)The first stageQuartz9218.0–293.1255.8From -13.7 to -3.0-7.64.98–17.9411.35The second stageQuartz39159.3–240.6184.5From -7.0 to -3.2-4.85.28–10.597.64The third stageQuartz8138.5–177.1157.3From -4.9 to -0.4-2.90.71–7.784.82Th: homogenization temperature; Tm (ice): melting temperature of ice. The salinity and density of the fluid inclusions are calculated by the equation of [23].Figure 9
(a) Frequency histogram of the homogenization temperature of the Daping metallogenic fluids. (b) Frequency histogram of the freezing temperature of metallogenic fluids. The homogenization temperature data and freezing temperature data are from microthermometric analysis of the fluid inclusions (this study).
(a)(b)


## 5.1. Major Elements

The test results of the major elements illustrate that the Daping gold ores have a high content of SiO2 and S and low content of Al2O3, TiO2, CaO, Na2O, MnO, and K2O (Table 3). With the increasing of gold mineralization, the intensity of silicification alteration and sulfide mineralization increased significantly.Table 3
Average content of the major elements of the Daping gold deposit (wt.%).
SampleSiO2Al2O3TFe2O3CaOMgOK2ONa2OTiO2P2O5MnOSO3LOITotalH375.6711.653.621.490.972.591.500.360.070.083.170.87102.04H573.1113.142.321.220.601.444.780.330.040.050.232.4199.67H667.5612.614.833.171.823.930.120.410.140.213.812.58101.19H767.4513.315.942.001.372.073.620.400.090.145.921.33103.64H869.5813.983.721.061.063.401.800.470.080.100.813.4699.52H2671.6810.236.301.861.312.610.870.400.030.093.540.9699.88H2876.507.865.761.640.911.820.990.290.120.063.900.94100.79H3467.9812.097.880.880.962.861.500.470.050.065.460.55100.74H4070.6112.625.241.320.862.931.750.500.090.074.420.53100.94H4365.8917.064.731.241.144.182.230.650.140.121.171.86100.41H4666.4914.544.512.901.783.561.320.570.130.122.062.22100.2H5164.7915.535.861.771.573.681.760.660.080.121.431.8199.06H5265.3613.174.693.821.903.461.280.410.090.231.803.6499.85H6265.7514.324.313.411.803.851.220.500.080.191.123.46100.01H8460.9318.184.772.991.594.661.300.680.080.142.612.81100.74Average68.6213.354.972.051.313.141.740.470.090.122.761.96


## 5.2. Trace Element

The trace element analysis results (Table4) show that the samples have wU/wTh ratios of 0.18–0.24 (0.20 in average), wRb/wSr ratios of 0.35–1.15 (0.68 in average), wCo/wNi ratios of 0.45–0.93 (0.68 in average), and wZr/wHf ratios of 32.50–34.26 (33.47 in average). The content values of U, Rb, and Co in the ores of Daping gold deposit are smaller than Th, Sr, and Ni. The content value of Zr is greater than Hf. The original mantle-standardized spider map shows that the elements of Li, Cr, Ni, Zn, Rb, Th, and Sr enriched obviously, and on the contrary, the elements of Sc, Co, Cu, Ga, Cs, Tl, and Zr were depleted (Figure 6).Table 4
Content of trace elements of the Daping gold deposit (ppm).
SampleH3H5H6H7H8H26H28H34H40H43H46H51H52H62H84AverageLi20.407.2014.609.5012.406.106.406.006.309.4013.4010.506.609.4011.109.95Sc8.009.709.4010.1011.008.606.009.3010.7014.1011.8014.609.9010.5013.5010.48V27.0017.0030.0028.0056.0050.0036.0057.0051.0068.0059.0077.0036.0050.0069.0047.40Cr35.008.0021.0024.0035.0031.0034.0033.0025.0025.0032.0040.0013.0018.0026.0026.67Co4.803.105.408.2010.808.307.607.708.509.309.3011.205.607.108.807.71Ni10.603.9011.4016.7014.0012.3011.7013.0010.6011.4017.7017.206.008.7010.8011.73Cu7.005.302.607.7022.4016.009.307.1014.6025.9015.2019.708.6011.7012.8012.39Zn25.0057.0015.0016.0022.0049.0031.0024.0017.0022.0020.0066.0018.0017.0021.0028.00Ga16.9013.6517.8516.1020.6014.5510.2015.0516.4021.2018.2520.4017.5517.6023.9017.35Rb88.4049.40121.5069.90111.5090.6060.6093.7097.10128.50113.50124.00111.00118.00148.50101.75Sr102.50165.50121.00143.0097.10211.00175.00142.00128.00136.50194.00204.00163.50200.00190.50158.24Nb9.609.3011.4010.7011.106.604.607.208.0010.709.2010.108.508.9011.509.16Cs15.652.8510.204.706.105.123.385.166.127.868.896.006.646.909.667.02Ta0.620.660.630.610.630.410.250.390.560.630.570.630.530.620.770.57Tl0.410.260.530.320.460.390.260.400.440.570.510.510.480.510.660.45Bi0.200.160.270.680.920.230.290.180.390.250.350.210.160.200.150.31Th6.529.028.017.999.015.574.346.376.999.779.178.877.479.4911.307.99U1.401.971.951.771.980.990.791.171.361.841.721.681.581.952.141.62Zr194.00234.00213.00191.00212.00125.0096.00145.00177.00242.00218.00195.00209.00205.00262.00194.53Hf5.807.206.305.806.503.702.904.405.207.206.405.806.106.007.905.81wU/wTh0.210.220.240.220.220.180.180.180.190.180.190.190.210.210.190.20wRb/wSr0.860.301.000.491.150.430.350.660.760.940.590.610.680.590.780.68wCo/wNi0.450.790.470.490.770.670.650.590.800.820.530.650.930.820.810.68wZr/wHf33.4532.5033.8132.9332.6233.7833.1032.9534.0433.6134.0633.6234.2634.1733.1633.47Figure 6
Primitive standard spider graph of trace elements of Daping gold deposit. The values for primitive mantle are from [62].


## 5.3. Rare Earth Element

Rare earth elements are important indications for the analysis of the ore-forming material sources due to their stable chemical properties and the specificity of distribution [24]. REE testing results (Table 5) show that the total amount of rare earth element (ΣREE) of the Daping gold ores is 98.20–218.76 ppm (160.58 ppm in average), the total amount of LREE is 88.38–192.36 ppm (142.38 ppm in average), the total amount of HREE is 9.82–26.40 ppm (18.20 ppm in average), the ratio of wLREE/wHREE is 6.91–9.00 (7.82 in average), and the ratio of wLaN/wYbN is 6.78–10.20 (7.95 in average). The δEu values ranging from 0.54 to 0.75 and the δCe values ranging from 1.05 to 1.09 show positive Ce anomaly and negative Eu anomaly. All of the samples have a similar REE pattern of right-dip type indicating that they may have homologous origins (Figure 6) [25].Table 5
Content of rare earth elements of the Daping gold deposit (ppm).
SampleH3H5H6H7H8H26H28H34H40H43H46H51H52H62H84AverageLa31.0035.5045.0039.9036.1020.5020.9026.0029.0038.4033.4033.7031.8033.6039.2032.93Ce64.4074.2090.4081.6075.6043.1042.4053.4061.0080.1069.5070.2067.1067.6082.3068.19Pr7.098.069.898.558.054.614.565.836.558.647.577.607.287.158.927.36Nd26.4029.2037.3031.1029.1017.0016.4021.8023.9031.9027.6028.3027.2025.8032.3027.02Sm5.835.947.856.336.343.503.434.544.996.755.965.935.875.336.775.69Eu1.160.961.921.241.300.740.690.961.011.451.291.271.171.151.471.19Gd5.125.067.705.125.853.222.894.004.185.644.915.165.414.875.694.99Tb0.880.781.190.800.920.480.450.630.680.900.770.840.850.780.870.79Dy5.094.876.644.675.602.922.553.644.125.434.825.055.214.585.514.71Ho1.071.061.390.971.150.630.530.750.841.120.991.011.100.961.150.98Er3.273.144.063.013.401.831.482.162.383.252.892.983.142.823.312.87Tm0.490.490.630.480.530.270.230.330.380.500.450.450.470.420.520.44Yb3.283.234.143.223.771.921.472.182.533.402.883.113.212.863.372.97Lu0.470.490.650.520.570.290.220.330.380.500.450.480.480.430.530.45Y33.2029.6042.6029.4033.5018.3015.6021.6024.6031.7029.4030.2031.4028.3033.3028.85ΣREE155.55172.98218.76187.51178.28101.0198.20126.55141.94187.98163.48166.08160.29158.35191.91160.58LREE135.88153.86192.36168.72156.4989.4588.38112.53126.45167.24145.32147.00140.42140.63170.96142.38HREE19.6719.1226.4018.7921.7911.569.8214.0215.4920.7418.1619.0819.8717.7220.9518.20wLREE/wHREE6.918.057.298.987.187.749.008.038.168.068.007.707.077.948.167.82wLaN/wYbN6.787.887.808.896.877.6610.208.558.228.108.327.777.118.438.347.95δEu0.650.540.750.670.650.670.670.690.680.720.730.700.630.690.720.68δCe1.071.081.051.081.091.091.061.061.091.081.071.081.081.071.081.07


## 5.4. Hydrogen and Oxygen Isotope

The hydrogen and oxygen isotope testing results (Table6) of quartz mineral samples show that the value of δDH2O is from -51‰ to 62‰ (-58.6‰ in average), and the value of δ18OH2O is from -1.44‰ to 5.42‰ (1.92‰ in average).Table 6
Isotopic values of D and O of the Daping gold deposit. The values of theδOH2O are yielded by the equation: δ18OQ–δ18OH2O≈3.38×106/T2−3.40 [22].
SampleMineralδD (‰)δOV-SMOW (‰)δOH2O (‰)T (°C)H28-OH1Quartz-6211.42.72255.8H34-OH1Quartz-5914.15.42255.8H22-OH1Quartz-6110.11.42255.8H10-OH1Quartz-6011.3-1.44184.5H16-OH1Quartz-5312.90.16184.5H26-OH1Quartz-62163.26184.5H9-OH1Quartz-6113.60.86184.5H46-OH1Quartz-5115.72.96184.5


## 5.5. Sulfur Isotope

The sulfur isotope is important for studying the source of ore-forming materials [26, 27]. Six sulfur isotope samples of metal sulfides (pyrite or arsenopyrite) were tested, and the testing results (Table 7) show that the value of δ34S is from -1.00‰ to 1.98‰ (-0.13‰ in average), which are close to the average S isotope of the magmatic hydrothermal deposit of 1.68‰ [28, 29].Table 7
Isotope values ofδ34S in the arsenopyrite or pyrite of the Daping gold deposit.
SampleMineralδ34S (‰)H34-S1Arsenopyrite-0.94H22-S1Arsenopyrite-1H16-S1Arsenopyrite-0.76H26-S1Arsenopyrite-0.67H7-S1Pyrite1.98H46-S1Pyrite0.23


## 5.6. Ore-Forming Fluid Inclusion Testing

According to the microscope observation, the ore-forming fluid inclusions are in the shape of circle, ellipse, or irregular. The metallogenic period of the Daping gold deposit can be divided into three stages. The inclusions of stage one are two-phase inclusions and liquid phase inclusions. The inclusions of stage two are two-phase inclusions, liquid phase inclusions, and gas inclusions. The inclusions of stage three are two-phase inclusions and gas phase inclusions. Based on the laser Raman spectra testing, the composition of the liquid phase inclusions is H2O, and the composition of the gas phase inclusions is H2O and CO2. For detailed characteristics of the fluid inclusions, see Table 1 and Figures 7 and 8.Figure 7
Photomicrographs of the typical fluid inclusions of the Daping gold deposit. (a) Two-phase and liquid phase of the first ore-forming stage. (b) Two-phase inclusions of the first ore-forming stage. (c) Two-phase, liquid phase, and gas phase inclusions of the second ore-forming stage. (d) Two-phase and gas phase inclusions of the third ore-forming stage. Abbreviation:LH2O: liquid H2O; GH2O: vapor H2O; GCO2: vapor CO2.
(a)(b)(c)(d)Figure 8
Microstructures and laser Raman spectra for fluid inclusions in Daping gold deposit.
(a)(b)The first stage of the ore-forming fluid yielded homogenization temperature of 218.0–293.1°C (255.8°C in average) and salinity of 4.98–17.94 wt.% NaCl eqv. (11.35 wt.% NaCl eqv. in average). The second stage of the ore-forming fluid yielded homogenization temperature of 159.3–240.6°C (184.5°C in average) and salinity of 5.28–10.59 wt.% NaCl eqv. (7.64 wt.% NaCl eqv. in average). The third stage of the ore-forming fluid yielded homogenization temperature of 138.5–177.1°C (157.3°C in average) and salinity of 0.71–7.78 wt.% NaCl eqv. (4.82 wt.% NaCl eqv. in average). For details of the fluid inclusion testing, see Table8 and Figure 9.Table 8
Microthermometric data of fluid inclusions of the metallogenic period in the Daping gold deposit.
StageHost mineralCountsTh (°C)AverageTh (°C)Tm (ice) (°C)AverageTm (ice) (°C)Salinity (wt.% NaCl eqv.)Average salinity (wt.% NaCl eqv.)The first stageQuartz9218.0–293.1255.8From -13.7 to -3.0-7.64.98–17.9411.35The second stageQuartz39159.3–240.6184.5From -7.0 to -3.2-4.85.28–10.597.64The third stageQuartz8138.5–177.1157.3From -4.9 to -0.4-2.90.71–7.784.82Th: homogenization temperature; Tm (ice): melting temperature of ice. The salinity and density of the fluid inclusions are calculated by the equation of [23].Figure 9
(a) Frequency histogram of the homogenization temperature of the Daping metallogenic fluids. (b) Frequency histogram of the freezing temperature of metallogenic fluids. The homogenization temperature data and freezing temperature data are from microthermometric analysis of the fluid inclusions (this study).
(a)(b)


## 6. Discussion

### 6.1. Source of Ore-Forming Materials and Fluids

The Pre-Cambrian basement of the middle Xuefeng Mountain area is composed of Lengjiaxi Group, Gaojian Group, and Nanhua System which have average gold content of 19.46 ppb, 41.86 ppb, and 20.51 ppb, respectively [30–32]. The gold content of the base rocks is 6.5–14 times than the average bulk continental crust of 3.0 ppb [33] and thus can provide an abundant initial gold source for the formation of the gold deposits in the middle Xuefeng Mountain area.Trace element studies show that the Daping gold ores enrich in Li, Cr, Ni, Zn, large ion lithophile elements of Rb and Sr, and high field strength element of Th and deplete in elements of Sc, Co, Cu, Ga, Cs, Tl, and Zr (Figure6). The chondrite standard distributions of REE curves of gold ores have similar patterns of right-dip indicating that they probably have the same material sources and origins [25]. The rare earth elements of the gold ores are characterized by the strong enrichment of LREE (Figure 10). The δEu values range from 0.54 to 0.75 which show negative Eu anomaly, indicating that Daping gold deposit may form in the reducing environment [24, 34].Figure 10
Chondrite meteorite standard distribution pattern of Daping gold deposit. The values for chondrite are from [63].On the diagram ofδ18OH2O vs. δDH2O (Figure 11), auriferous quartz of the Daping gold ores is mainly located between the magmatic water and meteoric water and partly located at magmatic water, which indicates that the metallogenic fluids may be the mixing fluids of magmatic waters and meteoric water. Considering that the Zhonghuashan granite and Huangmaoyuan granite (belonging to Baimashan complex granites) (Figure 1) are only a few kilometers away from Daping gold deposit and have δ18O value of 9.74–11.2‰ [35] which overlap partially with δ18O value of 10.1–15.7‰ of the Daping gold-bearing quart, this indicates that the metallogenic fluids may partly come from the deep concealed granite with mixing of the meteoric water, which is similar to the Chanziping deposit (Figure 12). The δ34S‰ values of sulfide isotope from metal sulfides of the Daping gold deposit range from -1 to 1.98, which are consistent with the granite; Gaojian Group (Figure 12) implied that both the granite and Gaojian Group may contribute to the sulfur sources.Figure 11
Plot ofδDH2O versus δ18OH2O of the metallogenic fluids in Daping gold deposit (modified after [1]). Primary magmatic and metamorphic water boxes and meteoric water line are from [64].Figure 12
Sulfur isotope composition of ores in Daping gold deposit (modified after [46, 65–67]). Data of the Lengjiaxi Group and Banxi Group (Gaojian Group) are from Luo [68] and Liu et al. [69].Most granites in middle Xuefeng Mountain and adjacent regions belong to S-type granites [35–37] and have low gold contents (e.g., the Baimashan complex granites have average gold content of 1.25 ppb [38]). Considering that the magma source of the granites have gold contents of 19.46–41.86 ppb which are much higher than the 1.25 ppb of granites, thus, the gold element may aggregate in the magmatic hydrothermal fluids and may partly contribute to the formation of Mesozoic regional gold deposits.


### 6.2. Metallogenic Mechanism

Based on Rb-Sr dating of quartz, the Daping gold deposit and Chanziping gold deposit occurred in 204.8 Ma and 205.6 Ma, respectively [18]. Large-scale regional thrusting nappe structures and associated acid magma intrusion activities occurred at 225–201 Ma of the Indosinian period [18, 36, 37]. Thus, the metallogenic epoch of regional gold mineralization is a little younger than the intrusion time of granites.The tectonic schistose foliation developed in auriferous veins (for example, I17 and I21) and ductile deformation of auriferous quartz veins (Figures 5(b), 5(d), and 5(e)) provides important evidence for the existence of brittle and ductile shear zones. The development of tectonic schistose foliation structure provides a migration channel for ore-forming fluids and serves as the main place for the precipitation and enrichment of ore-forming materials [39]. Driven by the thermal gradient of concealed granite, the gold metallogenic fluids migrate along the brittle and ductile shear zones, and in this process, the gold element of the adjacent stratum also adds to the fluids. When the ore-forming fluids reach the shallow stratum, and under the environment of depressurizing and fluid immiscibility, the thermodynamic equilibrium of CO2 and oxygen fugacity were destroyed, and thus, the gold element precipitated in the quartz and metal sulfides to form the gold ores [16].


### 6.3. Ore Genetic Type

As an important type of gold deposits in the world, the orogenic gold deposits provide at least 30% of global gold reserves [40], and 17 giant gold deposits (>500 t Au) around the world belong to the orogenic gold type. Since the evolutionary history of the orogenic belt can be recorded in the formation of the orogenic gold deposits [41], the study of the ore-forming process and genesis of the orogenic gold deposits can provide valuable information of metamorphism and uplift-erosion process of the orogenic belt and thus attracted more and more geologists to conduct research on such type of gold deposits. Before the jargon of orogenic gold deposits was proposed, the classification of the gold deposits which occurred in the orogenic belts or greenstone belts was in chaos. For instance, based on the differences of the surrounding rocks, the gold deposits were classified into green belt type, turbidite type, and BIF (banded iron formation) type [42]; based on the differences of mineralization characteristics, the gold deposits were classified into quartz vein type, altered rock type, and breccia type [43]; based on the differences of ore-controlling factors, the gold deposits were classified as shear zone type [44]. Groves et al. [45] proposed that the gold deposit formed in the tectonic environment of the squeezing or compression in the convergence region of the plates and has close genetic relationship with the orogenic process which can be classified as orogenic gold deposit, and thus, the gold types mentioned above should be classified as one type of orogenic gold deposit.The middle Xuefeng Mountain area is located in the transition zone between Cathaysian plate and Yangtze plate and had undergone many periods of crustal tectonic movement and forms a large number of faults and folds as well as a series of ductile-brittle shear zone structures and multiple metallogenic episodes including Paleozoic (e.g., Zixi gold deposit of 425 Ma [46]) and Late Triassic (e.g., Chanziping and Daping gold deposit). In the Indosinian period, due to the strong NW-SE compression tectonic activities and the intrusion activities of regional acidic magmas, the magmatic hydrothermal fluids upwelled along the shear zone, and the gold elements in the stratum were activated, migrated, and gradually precipitated and enriched in the proper weak tectonic structures (for instance, ductile-brittle shear structures).Similar Mesozoic gold deposits were also reported in the Jiangnan Orogen, e.g., Yanlinsi, Hengjiangchong, Wangu, Huangjindong, Jinjing, Mali, Fenshuiao, and Dayan [1, 4, 47–52]. And generally speaking, its gold mineralization has close spatial relations with regional granitic intrusions [1]. H–O–C–S–Pb isotopic data of ore-forming fluids indicate that its ore-forming materials mainly source from granitic magma and minor from basement metamorphic stratum ([1] and references therein). The ore-controlling structure of the shear zone of Daping gold deposit is similar to many world typical orogenic gold deposits [53–58]. In addition, the Daping gold deposit has many similar characteristics to the typical orogenic gold deposits (Table 9), for instance, the tectonic background of orogen, the ore-bearing rocks of semideep sea or deep sea sediments, the ore-type of quartz vein with metal sulfides, the alteration of silicification and carbonization, and the ore-forming fluids of CO2-H2O-NaCl. In summary, the Daping gold deposit may belong to an orogenic type.Table 9
The comparison of geological features between the Daping gold deposit and typical orogenic gold deposits.
Geological featuresTypical orogenic gold deposits (Groves et al. [45]; Wang et al. [46]; Qiu et al. [60]; Xu et al. [1]; Lu et al. [61])Daping gold depositTectonic backgroundTectonic compression environment of the orogenic beltThe Daping gold deposit is located in the transitional region of Xuefengshan orogenic belt between the Cathaysia plate and the Yangtze plateOre-bearing rocksMost of the Archaean gold deposits occur in greenstone belts, and the ore-hosting rocks are mainly tholeiitic volcanic rocks. Phanerozoic gold deposits are mainly hosted in semideep sea or deep sea turbidite. The host rocks generally underwent shallow-medium metamorphism of greenschist facies and amphibolite faciesThe wall rocks of the Daping gold ores are deep sea and semideep sea tuffaceous flysch formations of the Qingbaikou System with lithology assemblages mainly including slate, sandy slate, and sericite slateOre-controlling structureThe first-level fault is a large tectonic belt which cuts through the crust with a length of more than 100 km; the second-level fault has length of 1–10 km, and gold ore bodies are often located in the secondary level tectonic zones. The gold mineralization often occurred in the shear fracture and tension fractureThe Daping gold deposit is located in ca. 10 km southeast of the first-level deep fault of Anhua-Liping (about 350 km long). And second-level tectonics of the NE-trending ductile-brittle shear deformation zone of F8 (about 20 km long) cross through the Daping gold deposit from the middle. The mineralization structures are shear fracture of NW trend and tension fracture of the NE trendOre-typeThe gold mainly occurred in the quartz veins with 3–5% metal sulfidesThe gold mineralization mainly occurred in quartz veins and nearby metal sulfides, alteration rocks, and tectonic breccia rocksAlteration typeK-feldspathization, silicification, sericitization, carbonization, and sulfidationSilicification, sericitization, chloritization, carbonization, clayization, and sulfidationOre-forming fluidsMantle-derived fluid, magmatic fluid, metamorphic fluid, and atmospheric water. The ore-forming fluids are characterized by CO2-H2O-NaCl±CH4 and rich in CO2Magmatic fluid and atmospheric water. The ore-forming fluids are characterized by CO2-H2O-NaClMetallogenic temperature of the ore-forming fluids150°C–700°C157.3°C–255.8°CSalinity of the ore-forming fluids3–10 wt.% NaCl eqv.4.57–10.93% (NaCl eqv.)Assemblage of the metal elementsAu, Ag, ±As, Sb, Te, W, BiAu, As, ±Sb, ±Cu, ±PbMetallogenetic eraFrom the Neoarchaean to the Cenozoic eraThe gold mineralization occurred in Indosinian era


## 6.1. Source of Ore-Forming Materials and Fluids

The Pre-Cambrian basement of the middle Xuefeng Mountain area is composed of Lengjiaxi Group, Gaojian Group, and Nanhua System which have average gold content of 19.46 ppb, 41.86 ppb, and 20.51 ppb, respectively [30–32]. The gold content of the base rocks is 6.5–14 times than the average bulk continental crust of 3.0 ppb [33] and thus can provide an abundant initial gold source for the formation of the gold deposits in the middle Xuefeng Mountain area.Trace element studies show that the Daping gold ores enrich in Li, Cr, Ni, Zn, large ion lithophile elements of Rb and Sr, and high field strength element of Th and deplete in elements of Sc, Co, Cu, Ga, Cs, Tl, and Zr (Figure6). The chondrite standard distributions of REE curves of gold ores have similar patterns of right-dip indicating that they probably have the same material sources and origins [25]. The rare earth elements of the gold ores are characterized by the strong enrichment of LREE (Figure 10). The δEu values range from 0.54 to 0.75 which show negative Eu anomaly, indicating that Daping gold deposit may form in the reducing environment [24, 34].Figure 10
Chondrite meteorite standard distribution pattern of Daping gold deposit. The values for chondrite are from [63].On the diagram ofδ18OH2O vs. δDH2O (Figure 11), auriferous quartz of the Daping gold ores is mainly located between the magmatic water and meteoric water and partly located at magmatic water, which indicates that the metallogenic fluids may be the mixing fluids of magmatic waters and meteoric water. Considering that the Zhonghuashan granite and Huangmaoyuan granite (belonging to Baimashan complex granites) (Figure 1) are only a few kilometers away from Daping gold deposit and have δ18O value of 9.74–11.2‰ [35] which overlap partially with δ18O value of 10.1–15.7‰ of the Daping gold-bearing quart, this indicates that the metallogenic fluids may partly come from the deep concealed granite with mixing of the meteoric water, which is similar to the Chanziping deposit (Figure 12). The δ34S‰ values of sulfide isotope from metal sulfides of the Daping gold deposit range from -1 to 1.98, which are consistent with the granite; Gaojian Group (Figure 12) implied that both the granite and Gaojian Group may contribute to the sulfur sources.Figure 11
Plot ofδDH2O versus δ18OH2O of the metallogenic fluids in Daping gold deposit (modified after [1]). Primary magmatic and metamorphic water boxes and meteoric water line are from [64].Figure 12
Sulfur isotope composition of ores in Daping gold deposit (modified after [46, 65–67]). Data of the Lengjiaxi Group and Banxi Group (Gaojian Group) are from Luo [68] and Liu et al. [69].Most granites in middle Xuefeng Mountain and adjacent regions belong to S-type granites [35–37] and have low gold contents (e.g., the Baimashan complex granites have average gold content of 1.25 ppb [38]). Considering that the magma source of the granites have gold contents of 19.46–41.86 ppb which are much higher than the 1.25 ppb of granites, thus, the gold element may aggregate in the magmatic hydrothermal fluids and may partly contribute to the formation of Mesozoic regional gold deposits.


## 6.2. Metallogenic Mechanism

Based on Rb-Sr dating of quartz, the Daping gold deposit and Chanziping gold deposit occurred in 204.8 Ma and 205.6 Ma, respectively [18]. Large-scale regional thrusting nappe structures and associated acid magma intrusion activities occurred at 225–201 Ma of the Indosinian period [18, 36, 37]. Thus, the metallogenic epoch of regional gold mineralization is a little younger than the intrusion time of granites.The tectonic schistose foliation developed in auriferous veins (for example, I17 and I21) and ductile deformation of auriferous quartz veins (Figures 5(b), 5(d), and 5(e)) provides important evidence for the existence of brittle and ductile shear zones. The development of tectonic schistose foliation structure provides a migration channel for ore-forming fluids and serves as the main place for the precipitation and enrichment of ore-forming materials [39]. Driven by the thermal gradient of concealed granite, the gold metallogenic fluids migrate along the brittle and ductile shear zones, and in this process, the gold element of the adjacent stratum also adds to the fluids. When the ore-forming fluids reach the shallow stratum, and under the environment of depressurizing and fluid immiscibility, the thermodynamic equilibrium of CO2 and oxygen fugacity were destroyed, and thus, the gold element precipitated in the quartz and metal sulfides to form the gold ores [16].


## 6.3. Ore Genetic Type

As an important type of gold deposits in the world, the orogenic gold deposits provide at least 30% of global gold reserves [40], and 17 giant gold deposits (>500 t Au) around the world belong to the orogenic gold type. Since the evolutionary history of the orogenic belt can be recorded in the formation of the orogenic gold deposits [41], the study of the ore-forming process and genesis of the orogenic gold deposits can provide valuable information of metamorphism and uplift-erosion process of the orogenic belt and thus attracted more and more geologists to conduct research on such type of gold deposits. Before the jargon of orogenic gold deposits was proposed, the classification of the gold deposits which occurred in the orogenic belts or greenstone belts was in chaos. For instance, based on the differences of the surrounding rocks, the gold deposits were classified into green belt type, turbidite type, and BIF (banded iron formation) type [42]; based on the differences of mineralization characteristics, the gold deposits were classified into quartz vein type, altered rock type, and breccia type [43]; based on the differences of ore-controlling factors, the gold deposits were classified as shear zone type [44]. Groves et al. [45] proposed that the gold deposit formed in the tectonic environment of the squeezing or compression in the convergence region of the plates and has close genetic relationship with the orogenic process which can be classified as orogenic gold deposit, and thus, the gold types mentioned above should be classified as one type of orogenic gold deposit.The middle Xuefeng Mountain area is located in the transition zone between Cathaysian plate and Yangtze plate and had undergone many periods of crustal tectonic movement and forms a large number of faults and folds as well as a series of ductile-brittle shear zone structures and multiple metallogenic episodes including Paleozoic (e.g., Zixi gold deposit of 425 Ma [46]) and Late Triassic (e.g., Chanziping and Daping gold deposit). In the Indosinian period, due to the strong NW-SE compression tectonic activities and the intrusion activities of regional acidic magmas, the magmatic hydrothermal fluids upwelled along the shear zone, and the gold elements in the stratum were activated, migrated, and gradually precipitated and enriched in the proper weak tectonic structures (for instance, ductile-brittle shear structures).Similar Mesozoic gold deposits were also reported in the Jiangnan Orogen, e.g., Yanlinsi, Hengjiangchong, Wangu, Huangjindong, Jinjing, Mali, Fenshuiao, and Dayan [1, 4, 47–52]. And generally speaking, its gold mineralization has close spatial relations with regional granitic intrusions [1]. H–O–C–S–Pb isotopic data of ore-forming fluids indicate that its ore-forming materials mainly source from granitic magma and minor from basement metamorphic stratum ([1] and references therein). The ore-controlling structure of the shear zone of Daping gold deposit is similar to many world typical orogenic gold deposits [53–58]. In addition, the Daping gold deposit has many similar characteristics to the typical orogenic gold deposits (Table 9), for instance, the tectonic background of orogen, the ore-bearing rocks of semideep sea or deep sea sediments, the ore-type of quartz vein with metal sulfides, the alteration of silicification and carbonization, and the ore-forming fluids of CO2-H2O-NaCl. In summary, the Daping gold deposit may belong to an orogenic type.Table 9
The comparison of geological features between the Daping gold deposit and typical orogenic gold deposits.
Geological featuresTypical orogenic gold deposits (Groves et al. [45]; Wang et al. [46]; Qiu et al. [60]; Xu et al. [1]; Lu et al. [61])Daping gold depositTectonic backgroundTectonic compression environment of the orogenic beltThe Daping gold deposit is located in the transitional region of Xuefengshan orogenic belt between the Cathaysia plate and the Yangtze plateOre-bearing rocksMost of the Archaean gold deposits occur in greenstone belts, and the ore-hosting rocks are mainly tholeiitic volcanic rocks. Phanerozoic gold deposits are mainly hosted in semideep sea or deep sea turbidite. The host rocks generally underwent shallow-medium metamorphism of greenschist facies and amphibolite faciesThe wall rocks of the Daping gold ores are deep sea and semideep sea tuffaceous flysch formations of the Qingbaikou System with lithology assemblages mainly including slate, sandy slate, and sericite slateOre-controlling structureThe first-level fault is a large tectonic belt which cuts through the crust with a length of more than 100 km; the second-level fault has length of 1–10 km, and gold ore bodies are often located in the secondary level tectonic zones. The gold mineralization often occurred in the shear fracture and tension fractureThe Daping gold deposit is located in ca. 10 km southeast of the first-level deep fault of Anhua-Liping (about 350 km long). And second-level tectonics of the NE-trending ductile-brittle shear deformation zone of F8 (about 20 km long) cross through the Daping gold deposit from the middle. The mineralization structures are shear fracture of NW trend and tension fracture of the NE trendOre-typeThe gold mainly occurred in the quartz veins with 3–5% metal sulfidesThe gold mineralization mainly occurred in quartz veins and nearby metal sulfides, alteration rocks, and tectonic breccia rocksAlteration typeK-feldspathization, silicification, sericitization, carbonization, and sulfidationSilicification, sericitization, chloritization, carbonization, clayization, and sulfidationOre-forming fluidsMantle-derived fluid, magmatic fluid, metamorphic fluid, and atmospheric water. The ore-forming fluids are characterized by CO2-H2O-NaCl±CH4 and rich in CO2Magmatic fluid and atmospheric water. The ore-forming fluids are characterized by CO2-H2O-NaClMetallogenic temperature of the ore-forming fluids150°C–700°C157.3°C–255.8°CSalinity of the ore-forming fluids3–10 wt.% NaCl eqv.4.57–10.93% (NaCl eqv.)Assemblage of the metal elementsAu, Ag, ±As, Sb, Te, W, BiAu, As, ±Sb, ±Cu, ±PbMetallogenetic eraFrom the Neoarchaean to the Cenozoic eraThe gold mineralization occurred in Indosinian era


## 7. Conclusions

(1)
The Daping gold ores have features of high content values of SiO2, S, and As and low content values of Al2O3 and Na2O and have intense alteration of silicification and sericitization. The gold ores are enriched in Li, Cr, Ni, Zn, Rb, Th, and Sr and depleted in Sc, Co, Cu, Ga, Cs, Tl, and Zr. The chondrite REE distribution patterns of the gold ores display strong enrichment of LREE with δEu values ranging from 0.54 to 0.75(2)
Four ore-forming stages were identified: the first stage has mineral assemblages of quartz+pyrite+arsenopyrite±carbonate minerals, the second stage has mineral assemblages of quartz+polymetallic sulfide minerals (pyrite, arsenopyrite, chalcocite, galena, chalcopyrite, tetrahedrite)±chlorite±carbonate minerals, the third stage has mineral assemblages of quartz and carbonate minerals, and the supergene stage is characterized by limonite±patina which were formed by the oxidation of metal sulfides. Among them, the first stage and the second stage are the main gold mineralization stages(3)
The ore-forming fluid inclusions from quartz are composed of liquid phase (H2O) and gas phase (H2O and CO2). The main gold mineralization stages of the first stage and second stage yielded average homogenization temperature of 184.5 and 255.8°C and average salinity of 7.64 wt.% NaCl eqv. and 11.35 wt.% NaCl eqv., respectively. Thus, the ore-forming fluids may belong to H2O-CO2-NaCl, medium-low temperature, and medium-low salinity fluids(4)
The values ofδ34S of metal sulfides in Daping gold deposit range from -0.94‰ to 1.98‰ (-0.131‰ in average), the δDH2O and δ18OH2O values of auriferous quartz are from -51‰ to 62‰ and from -1.44‰ to 5.42‰, respectively, indicating that the sulfur may source from the concealed granite and/or Gaojian Group, and the ore-forming fluids may belong to mixing fluids of the magmatic fluid and meteoric hydrothermal fluid(5)
The Daping gold deposit formed in Indosinian period under the tectonic environment of compression between the Cathaysian plate and Yangtze plate and has similar features of the ore-bearing rocks, ore-controlling structures, alteration, and mineralization styles with typical orogenic gold deposits



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*Source: 6416174-2022-03-10.xml*