Infrared microthermometry allows direct measurement of fluid inclusions hosted in opaque ore minerals and can provide direct constraints on the evolution of ore-forming fluids.This study presents infrared microthermom...Infrared microthermometry allows direct measurement of fluid inclusions hosted in opaque ore minerals and can provide direct constraints on the evolution of ore-forming fluids.This study presents infrared microthermometry of spherite-hosted fluid inclusions from the Xinqiao deposit in the Middle-Lower Yangtze Metallogenic Belt and sheds new light on the ore genesis of the deposit.Considering that infrared light may lead to non-negligible temperature deviations during microthermometry,some tests were first conducted to ensure the accuracy of the microthermometric measurements.The measurement results indicated that using the lowest light intensity of the microscope and inserting an optical filter were effective in minimizing the possible temperature deviations of infrared microthermometry.All sphalerite-hosted fluid inclusions from the Xinqiao deposit were aqueous.They show homogenization temperature ranging from~200 to 350℃,but have two separate salinity groups(1.0 wt%-10 wt%and 15.1 wt%-19.2 wt%NaCl equivalent).The low-salinity group represents sedimentary exhalative(SEDEX)-associated fluids,whereas the high-salinity group results from modification by later magmatic hydrothermal fluids.Combined with published fluid inclusion data,the four-stage fluid evolution of the Xinqiao deposit was depicted.Furthermore,our data suggest that the Xinqiao deposit was formed by twostage metallogenic events including SEDEX and magmatic-hydrothermal mineralization.展开更多
Based on the study of the petrology, mineralogy, structural geology and fluid inclusion of the Dafulou ore deposit in the Dachang ore field, the ore deposit geology and ore-forming fluids were analyzed. It shows that ...Based on the study of the petrology, mineralogy, structural geology and fluid inclusion of the Dafulou ore deposit in the Dachang ore field, the ore deposit geology and ore-forming fluids were analyzed. It shows that there are five main hydrothermal alteration types in the Dafulou ore district, namely the silicification, carbonate, sericite, pyrite and pyrrhotite. The mineralization types are composed of the stratiform type, interlayer type and stockwork type. The ore textures present as metasomatic texture, euhedral-subhedral granular texture and solid solution texture. The ore structure consists of massive structure, dissemination structure, fine veined structure, stockwork structure and brecciated structure. Four ore types are recognized, namely the disseminated ore, dense massive ore, veinlet ore and brecciated ore. Six types of fluid inclusions are determined, i.e. the single-phase gaseous fluid inclusions, single-phase salt solution fluid inclusions, two-phase vapour-rich fluid inclusions, two-phase liquid-rich fluid inclusions, three-phase CO2-rich fluid inclusions and solid(s)-bearing fluid inclusions, all of which form in three dominant temperature scopes, 120-150, 230-270, 350-460 °C. But, the majority of them form in the high temperature environment (350-460 °C). The tectonism plays an important role in the mineralization, which usually controls the scale, occurrence and shape of the Sn orebody. There are four types of hydrothermal fluid systems, H2O-NaCl-CaCl2, H2O-CaCl2, H2O-NaCl-MgCl2 and H2O-MgCl2. Similar to the other ore deposits in the Dachang ore field, there also exists the multiple source of ore-forming fluids. Overall, the Dafulou ore deposit should be the result of the crust-mantle interaction.展开更多
Shawang gold deposit is a large gold deposit, located in the NE margin of the Jiaolai basin, which is part of Muping-Jimo metallogenic belt in eastern Shandong. It was controlled by the footwall of Guocheng fault zone...Shawang gold deposit is a large gold deposit, located in the NE margin of the Jiaolai basin, which is part of Muping-Jimo metallogenic belt in eastern Shandong. It was controlled by the footwall of Guocheng fault zone and secondary faults zone. Aiming to the fluid inclusions in Shawang gold deposit, the authors carry on petrographic, microthermometric and Raman spectroscopic component analyses. The results show that there are four-type fluid inclusions: single phase inclusions, gas-liquid two-phase inclusions, pure CO2 inclusions and three-phase inclusions containing CO2. Ore-forming fluid is characterized by low salinity (4.3%-12.6% NaC1. eqv), low density (0.64-0.97 g/cm3 ), medium-high temperature (280℃-320℃), metallogenic pressure with 81-94 MPa, and metallogenic depth as 7.39-7.98 kin. The fluid experienced immiscibility of CO2-NaCl- H2O system during the metallogenic process. In combination with the analysis of hydrogen and oxygen isotopes in fluid inclusions, it is determined that the Shawang gold deposit is mesothermal vein-type, with participation of mantle-derived water and magmatic water for its genesis.展开更多
Haigou gold deposit is a typical orogenic gold deposit. There are a reasonable amount of fluid inclusions in the gold deposit,including three types: CO2-H2O-Na Cl inclusions,pure CO2 inclusions and Na Cl-H2 O inclusio...Haigou gold deposit is a typical orogenic gold deposit. There are a reasonable amount of fluid inclusions in the gold deposit,including three types: CO2-H2O-Na Cl inclusions,pure CO2 inclusions and Na Cl-H2 O inclusions,of which most of them are CO2-bearing inclusions. The fluid salinity is 1. 43%- 9. 08%,mainly concentrated in the range of 4. 69%- 5. 41%,the density of CO2 is 0. 69- 0. 80 g / cm3,indicating that the mineralization fluid is low-medium salinity and low density fluid. A series of studies on gold-bearing quartz vein and fluid inclusions show that there exists a positive correlation between the degree of the gold mi-neralization and the amount of CO2 in the inclusions,which means the more CO2-bearing inclusions there are,the higher the content of gold is. CO2 is mainly derived from mantle fluid,and the ore-forming fluid should be derived from mantle fluid and the crust shallow fluid. The conclusions have important denotative meaning on the metallogenic mechanism of orogenic gold deposit and the deep prospecting on metal deposit.展开更多
Fluid inclusions from samples from the layered and veined mineralized belt in the Mopan mine area were studied using microscopic temperature measurements and laser Raman spectroscopy.Further studies were conducted on ...Fluid inclusions from samples from the layered and veined mineralized belt in the Mopan mine area were studied using microscopic temperature measurements and laser Raman spectroscopy.Further studies were conducted on the nature and source of the ore forming fluid and on the mechanism of deposit formation.The results show that there are three types of inclusions that occur in both the layered and veined ore body.These are liquid inclusions,CO 2 inclusions with a liquid phase,and NaCl-H 2 O multiphase inclusions.The fluid inclusions in both the layered and veined ore bodies have similar characteristics.The ore forming fluid is strongly reducing,was exposed to low to medium temperatures,salinity,and pressures.The source of this ore forming fluid was a mix of submarine volcanic spring(blow-piping),magmatic hydrothermal jet,and underground water.展开更多
The Qiangsheng gold deposit belongs to quartz vein type. The fluid inclusions consist of four types: aqueous single-phase inclusions, aqueous two-phase inclusions, carbonated two-phase inclusions and carbona- ted thr...The Qiangsheng gold deposit belongs to quartz vein type. The fluid inclusions consist of four types: aqueous single-phase inclusions, aqueous two-phase inclusions, carbonated two-phase inclusions and carbona- ted three-phase inclusions. The fluid inclusions are characterized by low salinity (5%-9% NaCl eqv) , low density (0.66-0.72 g/cm^3 ) and medium temperature (210℃-250℃). The pressure of ore-forming is 60-95 MPa and the metallogenic depth is about 5.49-7.56 km. During the mineralizing process, ore-forming fluid under- went fluid unmixing in CO2-H2O-NaCl system. The stable isotope resuhs indicate that the ore-forming fluids mainly generated from mantle, with the participation of a small amount of atmospheric water. Comprehensive studies have suggested that Qiangsheng gold deposit belongs to the type of mesothermal hydrotherm with mantlederived fluid participating in mineralization.展开更多
The Wadi Sharis orogenic gold deposit in northwestern Yemen is related to the fault and shear zones vein at medium depth in the crust in the Neoprotcrozoic meta-sedimentary and meta-volcanosedimentary succes- sion of ...The Wadi Sharis orogenic gold deposit in northwestern Yemen is related to the fault and shear zones vein at medium depth in the crust in the Neoprotcrozoic meta-sedimentary and meta-volcanosedimentary succes- sion of greenschist to amphibolite facies metamorphism. Three distinct fluid inclusion types have been identified in the gold-bearing quartz sulphide veins of the deposit: (1) type I: vapour-liquid two-phase (VH2O-LH2O ), (2) type II : three-phase CO2 ( VCO2 - LH2O - LCO2 ) and (3) type III: vapour-rich (LCO2 - VCO2 ) inclusions. Six analysis of individual fluid inclusion indicate the fluid inclusions comprise mainly of H2O and CO2. Forma- tion P-T conditions recorded by fluid inclusions in quartz crystals correspond to 180℃-380℃ and up to 130 MPa, as indicated by high-density CO2 bubbles (up to 0. 98 g/cm3 ) observed in some inclusions. The esti- mated crystallization pressures correspond to approximately 4-10 km of overburden, assuming a lithostatic load. The salinity ranges from 0 to 22 wt%. The deposit holds at 0.2-5 g/t Au and contains low-moderate salinity.展开更多
The types, composition and physico-chemical conditions of primary fluid inclusions were researched. The results show that the primary fluid inclusions contain vapor and liquid phase type (Type I), daughter mineral-b...The types, composition and physico-chemical conditions of primary fluid inclusions were researched. The results show that the primary fluid inclusions contain vapor and liquid phase type (Type I), daughter mineral-bearing type (Type II) and pure liquid phase type (Type III). The compositions of vapor are mainly H20 and CO2 with a tiny amounts of CH4 and H2; the liquid phase mainly contains Mg2+, Ca2+, Na+, K+, CI- and SO]-, and w(Na+)/w(K+)〉l; the homogenization temperatures of the primary fluid inclusions can be divided into 190-250 ℃, 250-340 ℃ and 360-420 ℃, corresponding to the salinities of 4%-9%, 9%-14%, and 14%-20.43% (NaC1 equivalent mass fraction), respectively. The mineralization process can be divided into three episodes: the silicatization stage, the quartz-sulfide stage, and the carbonatization stage, and all of them are associated with the ore-forming hydrothermal fluid activity. The origin of the hydrothermal fluid is from magrnatic water mainly, and later it mixes with the groundwater and meteoric water, which lead to the decrease of temperature and salinity. The decrease of salinity, temperature and pressure are the main causes of the metallogenic elements unloading and enriching in the favorable position.展开更多
The Qilishan gold deposit is located in the southern Zhaolai gold ore belt in the northwestern Jiaodong region.A total of seven gold ore bodies have been found in the mining area.Linglong gneissic biotite granite and ...The Qilishan gold deposit is located in the southern Zhaolai gold ore belt in the northwestern Jiaodong region.A total of seven gold ore bodies have been found in the mining area.Linglong gneissic biotite granite and the NE trending Lingbei fracture control the output and distribution of the gold deposit.The ore bodies with veined or irregular shape occur in the structural alteration zone.The ore bodies of different sizes are NE trending and SE dipping.The constituent minerals of the ores mainly include pyrite,chalcopyrite,native gold,electrum,argentite,matildite,hematite,quartz and calcite.The ores are characterized by metasomatic dissolution structure,as well as veined and brecciated structures.The ore-forming process is divided into four stages,namely quartz-,pyrite-,polymetallic-and carbonate stages.Study on fluid inclusion shows that the deposit is composed of gas-liquid two-phase inclusions (Ⅰ) and three-phase inclusions containing CO2 (Ⅱ),and that the former dominates.The homogenization temperature is 259.6℃-373.7℃ ; the salinity of three-phase inclusions containing CO2is 5.77%-9.84% (NaCl) ; the salinity of gas-liquid two-phase inclusions is 6.58%-8.54% (NaCl) ; and the estimated ore-forming pressure is 55.2-82.2 MPa.According to the nonlinear relationship between the depth and pressure of the fluid in the fracture zone,the ore-forming depth of the Qilishan gold deposit is calculated as 5.95-7.14 km.It is preliminarily determined that the deposit is a mesophilic and hypothermal gold deposit.展开更多
The Xiajinbao gold deposit is located in Yong’an-Xiayingfang-Maojiagou polymetallic metallogenic belt,which is animportant metallogenic belt in North China block.In this paper,we present a detailed study on fluid inc...The Xiajinbao gold deposit is located in Yong’an-Xiayingfang-Maojiagou polymetallic metallogenic belt,which is animportant metallogenic belt in North China block.In this paper,we present a detailed study on fluid inclusions and stable isotopes ofthe Xiajinbao gold deposit,Hebei Province,China,aiming at discussing the ore source,evolution of ore-forming fluid andore-forming mechanism of the deposit.The macroscopic geological characteristics,S and Pb isotopic analysis results show that thesource of ore-forming materials is mainly from granitic magma,and subordinately from country rocks.H and O isotopic compositionfeatures indicate that the ore-forming fluid is mainly derived from magmatic water.Fluid inclusion characteristics show that theore-forming fluid experienced boiling during the early mineralization stage,which led to the precipitation of gold.Fluid mixingdominated the precipitation of the ore-forming materials during the middle and late stages.The gold precipitation was caused bywater/rock reaction throughout the whole ore-forming process.展开更多
By means of microscopy and laser Raman spectroscopy, the authors studied the fluid inclusions in petrography. The results show that there exist three-phase CO2-bearing and two-phase aqueous inclusions in gold ore; the...By means of microscopy and laser Raman spectroscopy, the authors studied the fluid inclusions in petrography. The results show that there exist three-phase CO2-bearing and two-phase aqueous inclusions in gold ore; the fluid of NaC1-H2O-CO2 system went through immiscibility in ore-forming process. Ore-forming fluids were of low salinity (0. 82%- 5.40% NaCleqv), low density (0. 54-0.93 g/cm3 ) ; mineralization temperature were concentrated in 320℃-340℃ , with ore-forming pressure in 62-126 MPa and mineralization depth in 6.34-9.35 kin. The fluid inclusions in quartz are generally characterized by a small amount of CO2 and Na. Combined with recent results of the isotopic analysis for fluid inclusions and dating data, it was indicated that the main ore-forming fluids derived mainly from source of mantle-derived fluids with a small amount of magmatic fluid and meteoric water. The genetic type was mesothermal gold deposits involved by mantle-derived fluids.展开更多
基金supported by the National Key R&D Program of China(2018YFA0702701)the Fundamental Research Funds for the Central Universities(WK3410000015).
文摘Infrared microthermometry allows direct measurement of fluid inclusions hosted in opaque ore minerals and can provide direct constraints on the evolution of ore-forming fluids.This study presents infrared microthermometry of spherite-hosted fluid inclusions from the Xinqiao deposit in the Middle-Lower Yangtze Metallogenic Belt and sheds new light on the ore genesis of the deposit.Considering that infrared light may lead to non-negligible temperature deviations during microthermometry,some tests were first conducted to ensure the accuracy of the microthermometric measurements.The measurement results indicated that using the lowest light intensity of the microscope and inserting an optical filter were effective in minimizing the possible temperature deviations of infrared microthermometry.All sphalerite-hosted fluid inclusions from the Xinqiao deposit were aqueous.They show homogenization temperature ranging from~200 to 350℃,but have two separate salinity groups(1.0 wt%-10 wt%and 15.1 wt%-19.2 wt%NaCl equivalent).The low-salinity group represents sedimentary exhalative(SEDEX)-associated fluids,whereas the high-salinity group results from modification by later magmatic hydrothermal fluids.Combined with published fluid inclusion data,the four-stage fluid evolution of the Xinqiao deposit was depicted.Furthermore,our data suggest that the Xinqiao deposit was formed by twostage metallogenic events including SEDEX and magmatic-hydrothermal mineralization.
基金Project(41202051)supported by the National Natural Science Foundation of ChinaProject(2012M521721)supported by China Postdoctoral Science FoundationProject(CSUZC2013021)supported by Valuable Equipment Open Sharing Fund of Central South University,China
文摘Based on the study of the petrology, mineralogy, structural geology and fluid inclusion of the Dafulou ore deposit in the Dachang ore field, the ore deposit geology and ore-forming fluids were analyzed. It shows that there are five main hydrothermal alteration types in the Dafulou ore district, namely the silicification, carbonate, sericite, pyrite and pyrrhotite. The mineralization types are composed of the stratiform type, interlayer type and stockwork type. The ore textures present as metasomatic texture, euhedral-subhedral granular texture and solid solution texture. The ore structure consists of massive structure, dissemination structure, fine veined structure, stockwork structure and brecciated structure. Four ore types are recognized, namely the disseminated ore, dense massive ore, veinlet ore and brecciated ore. Six types of fluid inclusions are determined, i.e. the single-phase gaseous fluid inclusions, single-phase salt solution fluid inclusions, two-phase vapour-rich fluid inclusions, two-phase liquid-rich fluid inclusions, three-phase CO2-rich fluid inclusions and solid(s)-bearing fluid inclusions, all of which form in three dominant temperature scopes, 120-150, 230-270, 350-460 °C. But, the majority of them form in the high temperature environment (350-460 °C). The tectonism plays an important role in the mineralization, which usually controls the scale, occurrence and shape of the Sn orebody. There are four types of hydrothermal fluid systems, H2O-NaCl-CaCl2, H2O-CaCl2, H2O-NaCl-MgCl2 and H2O-MgCl2. Similar to the other ore deposits in the Dachang ore field, there also exists the multiple source of ore-forming fluids. Overall, the Dafulou ore deposit should be the result of the crust-mantle interaction.
基金Supported by projects of Shandong Province Geology and Mineral Bureau(No.KY201203)Shanhou Gold Deposit of Laixi of Shandong Province(SDLX2012-3-28)
文摘Shawang gold deposit is a large gold deposit, located in the NE margin of the Jiaolai basin, which is part of Muping-Jimo metallogenic belt in eastern Shandong. It was controlled by the footwall of Guocheng fault zone and secondary faults zone. Aiming to the fluid inclusions in Shawang gold deposit, the authors carry on petrographic, microthermometric and Raman spectroscopic component analyses. The results show that there are four-type fluid inclusions: single phase inclusions, gas-liquid two-phase inclusions, pure CO2 inclusions and three-phase inclusions containing CO2. Ore-forming fluid is characterized by low salinity (4.3%-12.6% NaC1. eqv), low density (0.64-0.97 g/cm3 ), medium-high temperature (280℃-320℃), metallogenic pressure with 81-94 MPa, and metallogenic depth as 7.39-7.98 kin. The fluid experienced immiscibility of CO2-NaCl- H2O system during the metallogenic process. In combination with the analysis of hydrogen and oxygen isotopes in fluid inclusions, it is determined that the Shawang gold deposit is mesothermal vein-type, with participation of mantle-derived water and magmatic water for its genesis.
基金Supported by Project of National Natural Science Foundation of China(No.41172072)
文摘Haigou gold deposit is a typical orogenic gold deposit. There are a reasonable amount of fluid inclusions in the gold deposit,including three types: CO2-H2O-Na Cl inclusions,pure CO2 inclusions and Na Cl-H2 O inclusions,of which most of them are CO2-bearing inclusions. The fluid salinity is 1. 43%- 9. 08%,mainly concentrated in the range of 4. 69%- 5. 41%,the density of CO2 is 0. 69- 0. 80 g / cm3,indicating that the mineralization fluid is low-medium salinity and low density fluid. A series of studies on gold-bearing quartz vein and fluid inclusions show that there exists a positive correlation between the degree of the gold mi-neralization and the amount of CO2 in the inclusions,which means the more CO2-bearing inclusions there are,the higher the content of gold is. CO2 is mainly derived from mantle fluid,and the ore-forming fluid should be derived from mantle fluid and the crust shallow fluid. The conclusions have important denotative meaning on the metallogenic mechanism of orogenic gold deposit and the deep prospecting on metal deposit.
文摘Fluid inclusions from samples from the layered and veined mineralized belt in the Mopan mine area were studied using microscopic temperature measurements and laser Raman spectroscopy.Further studies were conducted on the nature and source of the ore forming fluid and on the mechanism of deposit formation.The results show that there are three types of inclusions that occur in both the layered and veined ore body.These are liquid inclusions,CO 2 inclusions with a liquid phase,and NaCl-H 2 O multiphase inclusions.The fluid inclusions in both the layered and veined ore bodies have similar characteristics.The ore forming fluid is strongly reducing,was exposed to low to medium temperatures,salinity,and pressures.The source of this ore forming fluid was a mix of submarine volcanic spring(blow-piping),magmatic hydrothermal jet,and underground water.
基金Supported by projects of Geological Exploration of Jilin Province(No.22201300111)Shanhou Gold Deposit of Laixi of Shandong Province(SDLX2012-3-28)
文摘The Qiangsheng gold deposit belongs to quartz vein type. The fluid inclusions consist of four types: aqueous single-phase inclusions, aqueous two-phase inclusions, carbonated two-phase inclusions and carbona- ted three-phase inclusions. The fluid inclusions are characterized by low salinity (5%-9% NaCl eqv) , low density (0.66-0.72 g/cm^3 ) and medium temperature (210℃-250℃). The pressure of ore-forming is 60-95 MPa and the metallogenic depth is about 5.49-7.56 km. During the mineralizing process, ore-forming fluid under- went fluid unmixing in CO2-H2O-NaCl system. The stable isotope resuhs indicate that the ore-forming fluids mainly generated from mantle, with the participation of a small amount of atmospheric water. Comprehensive studies have suggested that Qiangsheng gold deposit belongs to the type of mesothermal hydrotherm with mantlederived fluid participating in mineralization.
文摘The Wadi Sharis orogenic gold deposit in northwestern Yemen is related to the fault and shear zones vein at medium depth in the crust in the Neoprotcrozoic meta-sedimentary and meta-volcanosedimentary succes- sion of greenschist to amphibolite facies metamorphism. Three distinct fluid inclusion types have been identified in the gold-bearing quartz sulphide veins of the deposit: (1) type I: vapour-liquid two-phase (VH2O-LH2O ), (2) type II : three-phase CO2 ( VCO2 - LH2O - LCO2 ) and (3) type III: vapour-rich (LCO2 - VCO2 ) inclusions. Six analysis of individual fluid inclusion indicate the fluid inclusions comprise mainly of H2O and CO2. Forma- tion P-T conditions recorded by fluid inclusions in quartz crystals correspond to 180℃-380℃ and up to 130 MPa, as indicated by high-density CO2 bubbles (up to 0. 98 g/cm3 ) observed in some inclusions. The esti- mated crystallization pressures correspond to approximately 4-10 km of overburden, assuming a lithostatic load. The salinity ranges from 0 to 22 wt%. The deposit holds at 0.2-5 g/t Au and contains low-moderate salinity.
基金Project(200911007-04) supported by the Special Funds for Scientific Research of Land and Natural Resources, ChinaProject (2007CB411405) supported by the National Basic Research Program of ChinaProject(20109901) supported by the National Crisis Office of China
文摘The types, composition and physico-chemical conditions of primary fluid inclusions were researched. The results show that the primary fluid inclusions contain vapor and liquid phase type (Type I), daughter mineral-bearing type (Type II) and pure liquid phase type (Type III). The compositions of vapor are mainly H20 and CO2 with a tiny amounts of CH4 and H2; the liquid phase mainly contains Mg2+, Ca2+, Na+, K+, CI- and SO]-, and w(Na+)/w(K+)〉l; the homogenization temperatures of the primary fluid inclusions can be divided into 190-250 ℃, 250-340 ℃ and 360-420 ℃, corresponding to the salinities of 4%-9%, 9%-14%, and 14%-20.43% (NaC1 equivalent mass fraction), respectively. The mineralization process can be divided into three episodes: the silicatization stage, the quartz-sulfide stage, and the carbonatization stage, and all of them are associated with the ore-forming hydrothermal fluid activity. The origin of the hydrothermal fluid is from magrnatic water mainly, and later it mixes with the groundwater and meteoric water, which lead to the decrease of temperature and salinity. The decrease of salinity, temperature and pressure are the main causes of the metallogenic elements unloading and enriching in the favorable position.
基金Supported by Project of Alternative Resources Prospecting in Crisis Mines(No.200623018)
文摘The Qilishan gold deposit is located in the southern Zhaolai gold ore belt in the northwestern Jiaodong region.A total of seven gold ore bodies have been found in the mining area.Linglong gneissic biotite granite and the NE trending Lingbei fracture control the output and distribution of the gold deposit.The ore bodies with veined or irregular shape occur in the structural alteration zone.The ore bodies of different sizes are NE trending and SE dipping.The constituent minerals of the ores mainly include pyrite,chalcopyrite,native gold,electrum,argentite,matildite,hematite,quartz and calcite.The ores are characterized by metasomatic dissolution structure,as well as veined and brecciated structures.The ore-forming process is divided into four stages,namely quartz-,pyrite-,polymetallic-and carbonate stages.Study on fluid inclusion shows that the deposit is composed of gas-liquid two-phase inclusions (Ⅰ) and three-phase inclusions containing CO2 (Ⅱ),and that the former dominates.The homogenization temperature is 259.6℃-373.7℃ ; the salinity of three-phase inclusions containing CO2is 5.77%-9.84% (NaCl) ; the salinity of gas-liquid two-phase inclusions is 6.58%-8.54% (NaCl) ; and the estimated ore-forming pressure is 55.2-82.2 MPa.According to the nonlinear relationship between the depth and pressure of the fluid in the fracture zone,the ore-forming depth of the Qilishan gold deposit is calculated as 5.95-7.14 km.It is preliminarily determined that the deposit is a mesophilic and hypothermal gold deposit.
基金Project(2015CX008) supported by the Innovation Driven Plan of Central South University,China
文摘The Xiajinbao gold deposit is located in Yong’an-Xiayingfang-Maojiagou polymetallic metallogenic belt,which is animportant metallogenic belt in North China block.In this paper,we present a detailed study on fluid inclusions and stable isotopes ofthe Xiajinbao gold deposit,Hebei Province,China,aiming at discussing the ore source,evolution of ore-forming fluid andore-forming mechanism of the deposit.The macroscopic geological characteristics,S and Pb isotopic analysis results show that thesource of ore-forming materials is mainly from granitic magma,and subordinately from country rocks.H and O isotopic compositionfeatures indicate that the ore-forming fluid is mainly derived from magmatic water.Fluid inclusion characteristics show that theore-forming fluid experienced boiling during the early mineralization stage,which led to the precipitation of gold.Fluid mixingdominated the precipitation of the ore-forming materials during the middle and late stages.The gold precipitation was caused bywater/rock reaction throughout the whole ore-forming process.
文摘By means of microscopy and laser Raman spectroscopy, the authors studied the fluid inclusions in petrography. The results show that there exist three-phase CO2-bearing and two-phase aqueous inclusions in gold ore; the fluid of NaC1-H2O-CO2 system went through immiscibility in ore-forming process. Ore-forming fluids were of low salinity (0. 82%- 5.40% NaCleqv), low density (0. 54-0.93 g/cm3 ) ; mineralization temperature were concentrated in 320℃-340℃ , with ore-forming pressure in 62-126 MPa and mineralization depth in 6.34-9.35 kin. The fluid inclusions in quartz are generally characterized by a small amount of CO2 and Na. Combined with recent results of the isotopic analysis for fluid inclusions and dating data, it was indicated that the main ore-forming fluids derived mainly from source of mantle-derived fluids with a small amount of magmatic fluid and meteoric water. The genetic type was mesothermal gold deposits involved by mantle-derived fluids.