The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brit...The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brittle fault system. There are three types of primary ore including auriferous calcite vein type, disseminated type, and breccia type, and the first two are important in the Phapon gold deposit. Based on fluid inclusion petrography and microthermometry, three types of primary fluid inclusions including type 1 liquid-rich aqueous, type 2 vapor-rich aqueous and type 3 daughter mineralbearing aqueous were identified in hydrothermal calcite grains. The ore-forming fluids are normally homogeneous, as indicated by the widespread type 1 inclusions with identical composition. The coexistence of type 1 and type 2 inclusions, showing similar final homogenization temperature but different compositions, indicate that fluid immiscibility did locally take place in both two types of ores. The results of microthermometry and H-O isotopes geochemistry indicate that there are little differences on ore-fluid geochemistry between the auriferous calcite vein-type and disseminated type ores. The oreforming fluids are characterized by medium-low temperatures(157–268 oC) and low salinity(1.6 wt.%–9.9 wt.% NaCl eq.). It is likely to have a metamorphic-dominant mixed source, which could be associated with dehydration and decarbonisation of Lower Permian limestone and Middle–Upper Triassic sandstones during the dynamic metamorphism. The fluid-wallrock interaction played a major role, and the locally occurred fluid-immiscible processes played a subordinate role in gold precipitation. Combined with the regional and ore deposit geology, and ore-fluid geochemistry, we suggest that the Phapon gold deposit is best considered to be a member of the epizonal orogenic deposit class.展开更多
The Jianbeigou gold deposit is a typical lode gold deposit in the Qinling metallogenic belt, located on the southern margin of the North China Craton. Three stages of the hydrothermal process can be distinguished, inc...The Jianbeigou gold deposit is a typical lode gold deposit in the Qinling metallogenic belt, located on the southern margin of the North China Craton. Three stages of the hydrothermal process can be distinguished, including the quartz ± pyrite, quartz-polymetallic sulfide, and quartz-carbonate ± pyrite stages. From the early to late stages, the homogenization temperatures of primary fluid inclusions are 281–362°C, 227–331°C, and 149–261°C, respectively. The corresponding salinities estimated for these fluids are 3.9–9.9 wt%, 0.4–9.4 wt%, and 0.7–7.2 wt% Na Cl equiv. Combined with laser Raman spectroscopy data, the ore-forming fluid belongs to a H_(2)O-CO_(2)-Na Cl ± CH_4 system with medium–low temperature and salinity. The δ~(18)Ofluid and δD values for the quartz veins are-1.0‰ to 6.0‰ and-105‰ to-84‰, respectively, which indicates that the ore-forming fluid is of mixed source, mainly derived from magma, with a contribution from meteoric water. Pyrite has been identified into three generations based on mineral paragenetic sequencing, including Py1, Py2, and Py3. The pyrites have δ~(34)S sulfur isotopic compositions from three stages between 3.7‰ and 8.4‰, indicating that sulfur mainly originated from magma. Te, Bi, Sb, and Cu contents in pyrite were all high and showed a strong correlation with Au concentrations. Native gold and the Au-Ag-Bi telluride minerals were formed concurrently, and the As concentration was low and decoupled from the Au content. Therefore, Te, Bi, Sb and other low-melting point chalcophile elements play an important role for gold mineralization in arsenic-deficient ore-forming fluid. Combined with the geological setting, evolution of pyrite, and ore-fluids geochemistry, we propose that the Jianbeigou deposit can be classified as a magmatic–hydrothermal lode gold deposit. Gold mineralization on the southern margin of the North China Craton is related to Early Cretaceous magmatism and formed in an extensional setting.展开更多
The Liwu stratiform copper deposit is located in the northwestern Jianglang dome,western China.Current studies mainly focus on the genetic type and mineralization of this deposit.Detailed fluid inclusion characteristi...The Liwu stratiform copper deposit is located in the northwestern Jianglang dome,western China.Current studies mainly focus on the genetic type and mineralization of this deposit.Detailed fluid inclusion characteristics of metallogenic period quartz veins were studied to reveal the ore-forming fluid features.Laser Raman analysis indicates that the ore-forming fluids is a H_(2)O-NaCl-CH_(4)(-CO_(2))system.Fluid inclusions microthermometry shows a homogenization temperature of 181-375°C and a salinity of 5.26%-16.99%for the disseminated-banded Cu-Zn mineralization;but a homogenization temperature of 142-343°C and a salinity of 5.41%-21.19%for the massive-veined Cu-Zn mineralization.These features suggest a medium-high temperature and a medium salinity for the ore-forming fluids.H-O isotopic data indicates that the ore-forming fluids were mainly from the metamorphic and magmatic water,plus minor formation water.And sulfur isotopic data indicates that sulfur was mainly derived from the formation and magmatic rocks.Metallogenesis of the disseminated-banded mineralization was mainly correlated with fluid mixing and water-rock reaction;whereas that of the massive-veined mineralization was mainly correlated with fluid boiling.The genetic type of the deposit is a medium-high temperature hydrothermal deposit related to magmatism and controlled by shear zones.This study is beneficial to understand the stratiform copper deposit.展开更多
The Huoshenmiao δeposit is Mo skarn δeposit, located in the western part of the Luanchuan ore δistrict.Mineralization process can be δivided into a skarn and a quartz-sulfide episodes with six stages: prograde(I),...The Huoshenmiao δeposit is Mo skarn δeposit, located in the western part of the Luanchuan ore δistrict.Mineralization process can be δivided into a skarn and a quartz-sulfide episodes with six stages: prograde(I), retrograde(II), quartz-K-feldspar(III), quartz-molybdenite(IV), quartz-pyrite(V), and quartzcalcite(VI). A combined study of geochronology, fluid inclusion(FI), and stable isotopes was conducted to constrain the mineralization age, source of ore materials, as well as the origin and evolution of the ore-forming fluids. Molybdenite Ree Os δating indicates that the δeposit was formed in the Late Jurassic(~145 Ma). The δ^(34)S values of sulfides range from 3.0‰ to 7.1‰, implying that the ore materials in the δeposit are magmatic in origin. Three types and six subtypes of FIs are δistinguished, namely, aqueous two-phase(W_1-and W_2-type), δaughter mineral-bearing multiphase(S_1-and S_2-type), and CO_2-bearing three-phase(C_1-and C_2-type). In stages I and II, the W_1-type FIs δisplay homogenization temperatures(Th) from 496°C to >600°C, with salinities of 14.9-18.3 wt.% NaCl eqv. The FIs in stages III, IV and early stage V composed of coeval S-, C-and W-types, respectively homogenize at similar Th, suggesting the occurrence of boiling. The W1-type FIs in late stage V and stage VI, yield Th of 102-406°C and salinities of 0-4.7 wt.% NaCl eqv. The δD_(H_2O)and δ^(18) O(H_2O)values of the ore-forming fluids in quartz-sulfide episode vary from-112‰ to-76‰, and 11.0‰ to 1.0‰, respectively. All these above observations reveal that the early ore-forming fluids are magmatic in origin, and characterized by high temperature and moderate to high salinity, and gradually evolve to low temperature, low salinity meteoric water. The Huoshenmiao Mo δeposit is associated with the magmatism event induced by the protracted subduction of the Izanagi plate beneath the eastern China continent. The δecrease in temperature, salinity and f(O_2), as well as change of p H δue to boiling and fluid-rock inte展开更多
The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inc...The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inclusions and H, O, and S stable isotopic compositions of the deposit. The fluid-inclusion data indicate that aqueous fluid inclusions were trapped in chalcopyrite-bearing quartz veins in the gangue minerals. The homogenization temperatures range from 108°C to 299°C, and the salinities range from 0.5% to 11.8%, indicating medium to low temperatures and salinities. The trapping pressures range from 34.5 MPa to 56.8 MPa. The δ^（18）O_（H_2O） values and δD values of the fluid range from -6.94‰ to -5.33‰ and from -95.31‰ to -48.20‰, respectively. The H and O isotopic data indicate that the ore-forming fluid derived from a mix of magmatic water and meteoric water and that meteoric water played a significant role. The S isotopic composition of pyrite ranges from 1.9‰ to 5.2‰, with an average value of 3.1‰, and the S isotopic composition of chalcopyrite ranges from -0.9‰ to 4‰, with an average value of 1.36‰, implying that the S in the ore-forming materials was derived from the mantle. The introduction of meteoric water decreased the temperature, volatile content, and pressure, resulting in immiscibility. These factors may have been the major causes of the mineralization of the Hongshi copper deposit. Based on all the geologic and fluid characteristics, we conclude that the Hongshi copper deposit is an epithermal deposit.展开更多
The Niujuan-Yingfang Pb-Zn-Ag deposit in northern North China Craton(NCC)is hosted at the contact zone between Permian biotite monzogranite and Hongqiyingzi Group migmatitic gneiss.The orebodies are structurally contr...The Niujuan-Yingfang Pb-Zn-Ag deposit in northern North China Craton(NCC)is hosted at the contact zone between Permian biotite monzogranite and Hongqiyingzi Group migmatitic gneiss.The orebodies are structurally controlled by NE-trending F1 fault.Mineralization can be divided into three stages:(1)siliceous-chlorite-pyrite stage,(2)quartz-Ag-base metal stage,and(3)fluorite-calcite stage.Four types of fluid inclusions were identified,including:(1)liquid-rich aqueous inclusions,(2)vapor-rich inclusions,(3)liquid-rich,solid-bearing inclusions,and(4)CO2-bearing inclusions.Mi-crothermometric measurements reveal that from stage I to III,the homogenization temperatures range from 317 to 262℃,from 297 to 192℃,and from 248 to 151℃,respectively,and the fluid salinities are in the ranges from 1.1 wt.%to 6.5 wt.%,1.2 wt.%to 6.0 wt.%and 0.7 wt.%to 4.0 wt.%NaCl equiva-lents,respectively.Fluid boiling and cooling are the two important mechanisms for ore precipitation according to microthermometric data,and fluid-rock interaction is also indispensable.Laser Raman spectroscopic analyses indicate the fluid system of the deposit is composed of CO2-NaCl-H2O±N2.Me-tallogenic fluorites yielded a Sm-Nd isochron age of 158±35 Ma.Theδ34SV-CDt values of sulfides range from-1.3‰ to 6.3‰,suggesting that the sulfur may be inherited from the basement metamorphic ig-neous rocks.Hydrogen and oxygen isotopic compositions of quartz indicate a metamorphic origin for the ore-forming fluid,and the proportion of meteoric water increased during the ore-forming processes.Sr-Nd isotopes of fluorites show a crustal source for the ore-forming fluid,with primary metamorphic fluid mixed with meteoric water during ascent to lower crustal levels.Combined with the geological,metallogenic epoch,fluid inclusions,H-O-S and Sr-Nd isotopes characteristics of the deposit,we suggest that the Niujuan-Yingfang deposit belongs to the medium-low temperature hydrothermal vein-type Pb-Zn-Ag polymetallic deposit,with ore-forming fluids dominantly originated from展开更多
The metallogenic environment of the Irtysh gold belt in Xinjiang is studied in detail.The metallogenic geological background,metallogenic conditions and ore-controlling factors of the gold deposits in eastern,central ...The metallogenic environment of the Irtysh gold belt in Xinjiang is studied in detail.The metallogenic geological background,metallogenic conditions and ore-controlling factors of the gold deposits in eastern,central and western regions of the metallogenic belt are compared.The metallogenic structure of the Irtysh tectonic belt has the characteristics of diverging to the west and converging to the east.Composite ore controlling by ductile shearing and magmatic activity in Irtysh gold belt result in zoned and segmented distribution of gold mineralization.Through the fluid inclusion research and H-O-S isotope analysis,the evolution regularity of gold ore-forming fluids in the region was analyzed.Synchrotron radiation X-ray fluorescence was used to analysis the concentration of metal elements in a single fluid inclusion,explaining the occurrence and migration process of Au in hydrothermal fluid.The source of ore forming minerals in western gold deposit is more closely related to magmatic activity,and the structural metamorphism of eastern gold deposit has greater influence on mineralization.Metallogenic fluids of gold deposits are characterized by metamorphic water(and magmatic water)in the early stage and mixed with meteoric water in the late stage.And the metallogenic elements are enriched in CO2 rich fluid.The Au is mainly activated,migrated and enriched with the mixed fluid of magmatic hydrothermal,metamorphic hydrothermal and atmospheric precipitation in the medium-low temperature,shallow to medium-deep environment.展开更多
The Qinggouzi stibnite deposit is located in Huashan Town,Jilin Province,in the northeastern margin of North China Craton(NCC).It is controlled by fault structures,hosted within structurally controlled felsic dykes,pr...The Qinggouzi stibnite deposit is located in Huashan Town,Jilin Province,in the northeastern margin of North China Craton(NCC).It is controlled by fault structures,hosted within structurally controlled felsic dykes,predominantly surrounded by phyllite,schist and quartzite.This study presents the results of fluid inclusions studies,intending to determine the source of the fluid responsible for ore-formation,hence exploring its metallogenesis.The aqueous biphase inclusions are identified in the stibnite-bearing quartz veins of the deposit.Moreover,aqueous biphase inclusions are further classified into(1)biphase liquid-rich inclusions(1 a)and(2)biphase gas-rich inclusions(1 b)depending upon liquid to gas ratio trapped within the fluid inclusions.Homogenization temperatures for(1 a)and(1 b)range between 114.8℃to 422℃and 128.3℃to 267.5℃,respectively.1 a and 1 b have salinities of 0.18%to 16.14%NaCleqv and 1.22%to 12.88%NaCleqv,and density range from 0.43 to 1.02 g/cm^(3) and 0.81 to 0.98 g/cm^(3),respectively.Sulfur isotopic analysis indicatesδ34SV-CDT from 4.4×10-3 to 6.5×10^(-3),with an average of 5.2×10^(-3),whereas H isotopes values onδDV-SMOW standard are-100.8×10^(-3) and-107.5×10^(-3),while O isotopes data onδ18OV-SMOW standard range between 20.1×10^(-3) and 20.4×10-3.Fluid inclusions study,combining with sulfur and H-O isotopic data reveal that the ore-forming fluids originated from deep source and were subsequently contaminated by meteoric water.Hydrostatic pressure calculation shows that the minimum and maximum pressures are 11.65 and 42.33 MPa,and relevant depths of deposit are estimated to be 1.16 and 4.23 km.Finally,we inferred that Qinggouzi stibnite deposit is a medium-low temperature,low salinity hydrothermal deposit,which is formed by deep source and later contaminated by meteoric water,and is classified as epizonal deposit in terms of orogenic series.展开更多
We studied the fluid inclusions of the Jiguanshan Mo deposit in China,which is a large porphyry deposit located in the southern Xilamulun Metallogenic Belt.The irregular Mo ore body with various types of hydrothermal ...We studied the fluid inclusions of the Jiguanshan Mo deposit in China,which is a large porphyry deposit located in the southern Xilamulun Metallogenic Belt.The irregular Mo ore body with various types of hydrothermal veinlets is hosted by Late Jurassic granite porphyry.Intense hydrothermal alterations in the deposit from the core to margin are silicification-potassium feldspar alteration,pyrite-quartz-sericite-fluorite alteration,and propylitic alteration.Based on the mineral assemblages and crosscutting relationships of ore veins,the ore-forming process were divided into three stages and two substages:quartz-pyrite veins(stage I)associated with potassic alteration;quartz-molybdenite-chalcopyrite-pyrite veins(substage Ⅱ-1)and quartz-molybdenite-fluorite veins(substage Ⅱ-2)associated with phyllic alteration;and fluorite-quartz-carbonate veins(stage Ⅲ)with carbonation.Five majorfluid inclusions(FIs)types were distinguished in the quartz associated with oxide and sulfide minerals,i.e.polyphase brine(Pb-type),opaque-bearing brine(Ob-type),solid halite(S-type),two-phase aqueous(A-type),and vapor(Vtype)inclusions.The FIs of stage I were composed of liquid-rich S-,A-,and V-type FIs with homogenization temperatures and salinities of 490 to 511℃ and 8.9 to 56.0 wt%NaCl equiv.,respectively.The FIs of substage Ⅱ-1 are composed of Pb-,Ob-,S-,A-,and V-type FIs with homogenization temperatures and salinities of 352 to 460℃ and 3.7 to 46.1 wt%NaCl equiv,respectively.The FIs of substage Ⅱ-2 are Ob-,S-,A-,and V-type FIs with homogenization temperatures and salinities of 234 to309°C and 3.7 to 39.2 wt%NaCl equiv,respectively.The FIs of stage Ⅲ are A-type FIs with homogenization temperatures and salinities of 136 to 172℃ and 1.1 to 8.9 wt%NaCl equiv,respectively.Fluid boiling,which resulted in the precipitation of sulfides,occurred in stages I andⅡ.The initial ore-forming fluids of the Jiguanshan deposit had high temperature,high salinity,and belonged to an F-rich NaCl±KCl-H2O system.The fluids gradually evolv展开更多
基金financially supported by the China Geological Survey Project (No. 121201010000150013)
文摘The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brittle fault system. There are three types of primary ore including auriferous calcite vein type, disseminated type, and breccia type, and the first two are important in the Phapon gold deposit. Based on fluid inclusion petrography and microthermometry, three types of primary fluid inclusions including type 1 liquid-rich aqueous, type 2 vapor-rich aqueous and type 3 daughter mineralbearing aqueous were identified in hydrothermal calcite grains. The ore-forming fluids are normally homogeneous, as indicated by the widespread type 1 inclusions with identical composition. The coexistence of type 1 and type 2 inclusions, showing similar final homogenization temperature but different compositions, indicate that fluid immiscibility did locally take place in both two types of ores. The results of microthermometry and H-O isotopes geochemistry indicate that there are little differences on ore-fluid geochemistry between the auriferous calcite vein-type and disseminated type ores. The oreforming fluids are characterized by medium-low temperatures(157–268 oC) and low salinity(1.6 wt.%–9.9 wt.% NaCl eq.). It is likely to have a metamorphic-dominant mixed source, which could be associated with dehydration and decarbonisation of Lower Permian limestone and Middle–Upper Triassic sandstones during the dynamic metamorphism. The fluid-wallrock interaction played a major role, and the locally occurred fluid-immiscible processes played a subordinate role in gold precipitation. Combined with the regional and ore deposit geology, and ore-fluid geochemistry, we suggest that the Phapon gold deposit is best considered to be a member of the epizonal orogenic deposit class.
基金jointed supported by National Key Research and Development Program of China (Grant No. 2021YFC2901704)the National Natural Science Foundation of China (Grant No. 41930430)the State Key Laboratory of Lithospheric Evolution, IGGCAS (Grant No. SKL-Z201905)。
文摘The Jianbeigou gold deposit is a typical lode gold deposit in the Qinling metallogenic belt, located on the southern margin of the North China Craton. Three stages of the hydrothermal process can be distinguished, including the quartz ± pyrite, quartz-polymetallic sulfide, and quartz-carbonate ± pyrite stages. From the early to late stages, the homogenization temperatures of primary fluid inclusions are 281–362°C, 227–331°C, and 149–261°C, respectively. The corresponding salinities estimated for these fluids are 3.9–9.9 wt%, 0.4–9.4 wt%, and 0.7–7.2 wt% Na Cl equiv. Combined with laser Raman spectroscopy data, the ore-forming fluid belongs to a H_(2)O-CO_(2)-Na Cl ± CH_4 system with medium–low temperature and salinity. The δ~(18)Ofluid and δD values for the quartz veins are-1.0‰ to 6.0‰ and-105‰ to-84‰, respectively, which indicates that the ore-forming fluid is of mixed source, mainly derived from magma, with a contribution from meteoric water. Pyrite has been identified into three generations based on mineral paragenetic sequencing, including Py1, Py2, and Py3. The pyrites have δ~(34)S sulfur isotopic compositions from three stages between 3.7‰ and 8.4‰, indicating that sulfur mainly originated from magma. Te, Bi, Sb, and Cu contents in pyrite were all high and showed a strong correlation with Au concentrations. Native gold and the Au-Ag-Bi telluride minerals were formed concurrently, and the As concentration was low and decoupled from the Au content. Therefore, Te, Bi, Sb and other low-melting point chalcophile elements play an important role for gold mineralization in arsenic-deficient ore-forming fluid. Combined with the geological setting, evolution of pyrite, and ore-fluids geochemistry, we propose that the Jianbeigou deposit can be classified as a magmatic–hydrothermal lode gold deposit. Gold mineralization on the southern margin of the North China Craton is related to Early Cretaceous magmatism and formed in an extensional setting.
基金financially supported by National Natural Science Foundation of China(42272106,41202067)Open Fund of State Key Laboratory for Mineral Deposits Research,Nanjing University(2019-LAMD-K12)China Geological Survey(DD20211386,DD20211392,DD20179603).
文摘The Liwu stratiform copper deposit is located in the northwestern Jianglang dome,western China.Current studies mainly focus on the genetic type and mineralization of this deposit.Detailed fluid inclusion characteristics of metallogenic period quartz veins were studied to reveal the ore-forming fluid features.Laser Raman analysis indicates that the ore-forming fluids is a H_(2)O-NaCl-CH_(4)(-CO_(2))system.Fluid inclusions microthermometry shows a homogenization temperature of 181-375°C and a salinity of 5.26%-16.99%for the disseminated-banded Cu-Zn mineralization;but a homogenization temperature of 142-343°C and a salinity of 5.41%-21.19%for the massive-veined Cu-Zn mineralization.These features suggest a medium-high temperature and a medium salinity for the ore-forming fluids.H-O isotopic data indicates that the ore-forming fluids were mainly from the metamorphic and magmatic water,plus minor formation water.And sulfur isotopic data indicates that sulfur was mainly derived from the formation and magmatic rocks.Metallogenesis of the disseminated-banded mineralization was mainly correlated with fluid mixing and water-rock reaction;whereas that of the massive-veined mineralization was mainly correlated with fluid boiling.The genetic type of the deposit is a medium-high temperature hydrothermal deposit related to magmatism and controlled by shear zones.This study is beneficial to understand the stratiform copper deposit.
基金funded by the National Key R&D Plan (Nos. 2017YFC0601403 and 2016YFC0600106)the National Natural Science Foundation of China (No. 41272110)the basic research program of the First Institute of Oceanography (No. 2015T02)
文摘The Huoshenmiao δeposit is Mo skarn δeposit, located in the western part of the Luanchuan ore δistrict.Mineralization process can be δivided into a skarn and a quartz-sulfide episodes with six stages: prograde(I), retrograde(II), quartz-K-feldspar(III), quartz-molybdenite(IV), quartz-pyrite(V), and quartzcalcite(VI). A combined study of geochronology, fluid inclusion(FI), and stable isotopes was conducted to constrain the mineralization age, source of ore materials, as well as the origin and evolution of the ore-forming fluids. Molybdenite Ree Os δating indicates that the δeposit was formed in the Late Jurassic(~145 Ma). The δ^(34)S values of sulfides range from 3.0‰ to 7.1‰, implying that the ore materials in the δeposit are magmatic in origin. Three types and six subtypes of FIs are δistinguished, namely, aqueous two-phase(W_1-and W_2-type), δaughter mineral-bearing multiphase(S_1-and S_2-type), and CO_2-bearing three-phase(C_1-and C_2-type). In stages I and II, the W_1-type FIs δisplay homogenization temperatures(Th) from 496°C to >600°C, with salinities of 14.9-18.3 wt.% NaCl eqv. The FIs in stages III, IV and early stage V composed of coeval S-, C-and W-types, respectively homogenize at similar Th, suggesting the occurrence of boiling. The W1-type FIs in late stage V and stage VI, yield Th of 102-406°C and salinities of 0-4.7 wt.% NaCl eqv. The δD_(H_2O)and δ^(18) O(H_2O)values of the ore-forming fluids in quartz-sulfide episode vary from-112‰ to-76‰, and 11.0‰ to 1.0‰, respectively. All these above observations reveal that the early ore-forming fluids are magmatic in origin, and characterized by high temperature and moderate to high salinity, and gradually evolve to low temperature, low salinity meteoric water. The Huoshenmiao Mo δeposit is associated with the magmatism event induced by the protracted subduction of the Izanagi plate beneath the eastern China continent. The δecrease in temperature, salinity and f(O_2), as well as change of p H δue to boiling and fluid-rock inte
基金financially supported by the National Key R&D Program of China(2017YFC0601201-2)funds from the Chinese Ministry of Land and Resources for public welfare industry research(201411026-1)the Chinese Geological Survey Project(DD20160071)
文摘The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inclusions and H, O, and S stable isotopic compositions of the deposit. The fluid-inclusion data indicate that aqueous fluid inclusions were trapped in chalcopyrite-bearing quartz veins in the gangue minerals. The homogenization temperatures range from 108°C to 299°C, and the salinities range from 0.5% to 11.8%, indicating medium to low temperatures and salinities. The trapping pressures range from 34.5 MPa to 56.8 MPa. The δ^（18）O_（H_2O） values and δD values of the fluid range from -6.94‰ to -5.33‰ and from -95.31‰ to -48.20‰, respectively. The H and O isotopic data indicate that the ore-forming fluid derived from a mix of magmatic water and meteoric water and that meteoric water played a significant role. The S isotopic composition of pyrite ranges from 1.9‰ to 5.2‰, with an average value of 3.1‰, and the S isotopic composition of chalcopyrite ranges from -0.9‰ to 4‰, with an average value of 1.36‰, implying that the S in the ore-forming materials was derived from the mantle. The introduction of meteoric water decreased the temperature, volatile content, and pressure, resulting in immiscibility. These factors may have been the major causes of the mineralization of the Hongshi copper deposit. Based on all the geologic and fluid characteristics, we conclude that the Hongshi copper deposit is an epithermal deposit.
基金This study was supported by the National Key Research and Development Program(No.2018YFC0603801)the China Geological Survey Program(No.12120115033601).
文摘The Niujuan-Yingfang Pb-Zn-Ag deposit in northern North China Craton(NCC)is hosted at the contact zone between Permian biotite monzogranite and Hongqiyingzi Group migmatitic gneiss.The orebodies are structurally controlled by NE-trending F1 fault.Mineralization can be divided into three stages:(1)siliceous-chlorite-pyrite stage,(2)quartz-Ag-base metal stage,and(3)fluorite-calcite stage.Four types of fluid inclusions were identified,including:(1)liquid-rich aqueous inclusions,(2)vapor-rich inclusions,(3)liquid-rich,solid-bearing inclusions,and(4)CO2-bearing inclusions.Mi-crothermometric measurements reveal that from stage I to III,the homogenization temperatures range from 317 to 262℃,from 297 to 192℃,and from 248 to 151℃,respectively,and the fluid salinities are in the ranges from 1.1 wt.%to 6.5 wt.%,1.2 wt.%to 6.0 wt.%and 0.7 wt.%to 4.0 wt.%NaCl equiva-lents,respectively.Fluid boiling and cooling are the two important mechanisms for ore precipitation according to microthermometric data,and fluid-rock interaction is also indispensable.Laser Raman spectroscopic analyses indicate the fluid system of the deposit is composed of CO2-NaCl-H2O±N2.Me-tallogenic fluorites yielded a Sm-Nd isochron age of 158±35 Ma.Theδ34SV-CDt values of sulfides range from-1.3‰ to 6.3‰,suggesting that the sulfur may be inherited from the basement metamorphic ig-neous rocks.Hydrogen and oxygen isotopic compositions of quartz indicate a metamorphic origin for the ore-forming fluid,and the proportion of meteoric water increased during the ore-forming processes.Sr-Nd isotopes of fluorites show a crustal source for the ore-forming fluid,with primary metamorphic fluid mixed with meteoric water during ascent to lower crustal levels.Combined with the geological,metallogenic epoch,fluid inclusions,H-O-S and Sr-Nd isotopes characteristics of the deposit,we suggest that the Niujuan-Yingfang deposit belongs to the medium-low temperature hydrothermal vein-type Pb-Zn-Ag polymetallic deposit,with ore-forming fluids dominantly originated from
基金This work was financially supported by the National Natural Science Foundation of China(Nos.41372096,41672070)Field work has been supported by colleagues from University of Science and Technology,Beijing,China Non-Ferrous Metals Resources Geological Survey and the relevant geological departments in Xinjiang+2 种基金Teacher Mu Liu from Analytical Testing Research in Center Beijing Research Institute of Uranium Geology(BRIUG)provided assistance for H-O-S isotope testingProfessor Guang Fan and Teacher Xiangkun Ge provided guidance and assistance for the electron probe experimentSynchrotron radiation X-ray fluorescence analysis was supported and helped by Professor Aiguo Li,Lili Zhang and Shuai Yan,Shanghai Institute of Applied Physics,Chinese Academy of Sciences.
文摘The metallogenic environment of the Irtysh gold belt in Xinjiang is studied in detail.The metallogenic geological background,metallogenic conditions and ore-controlling factors of the gold deposits in eastern,central and western regions of the metallogenic belt are compared.The metallogenic structure of the Irtysh tectonic belt has the characteristics of diverging to the west and converging to the east.Composite ore controlling by ductile shearing and magmatic activity in Irtysh gold belt result in zoned and segmented distribution of gold mineralization.Through the fluid inclusion research and H-O-S isotope analysis,the evolution regularity of gold ore-forming fluids in the region was analyzed.Synchrotron radiation X-ray fluorescence was used to analysis the concentration of metal elements in a single fluid inclusion,explaining the occurrence and migration process of Au in hydrothermal fluid.The source of ore forming minerals in western gold deposit is more closely related to magmatic activity,and the structural metamorphism of eastern gold deposit has greater influence on mineralization.Metallogenic fluids of gold deposits are characterized by metamorphic water(and magmatic water)in the early stage and mixed with meteoric water in the late stage.And the metallogenic elements are enriched in CO2 rich fluid.The Au is mainly activated,migrated and enriched with the mixed fluid of magmatic hydrothermal,metamorphic hydrothermal and atmospheric precipitation in the medium-low temperature,shallow to medium-deep environment.
基金Supported by Project of Jilin Province Geological Exploration Fund(No.2018.G.P.36-30)。
文摘The Qinggouzi stibnite deposit is located in Huashan Town,Jilin Province,in the northeastern margin of North China Craton(NCC).It is controlled by fault structures,hosted within structurally controlled felsic dykes,predominantly surrounded by phyllite,schist and quartzite.This study presents the results of fluid inclusions studies,intending to determine the source of the fluid responsible for ore-formation,hence exploring its metallogenesis.The aqueous biphase inclusions are identified in the stibnite-bearing quartz veins of the deposit.Moreover,aqueous biphase inclusions are further classified into(1)biphase liquid-rich inclusions(1 a)and(2)biphase gas-rich inclusions(1 b)depending upon liquid to gas ratio trapped within the fluid inclusions.Homogenization temperatures for(1 a)and(1 b)range between 114.8℃to 422℃and 128.3℃to 267.5℃,respectively.1 a and 1 b have salinities of 0.18%to 16.14%NaCleqv and 1.22%to 12.88%NaCleqv,and density range from 0.43 to 1.02 g/cm^(3) and 0.81 to 0.98 g/cm^(3),respectively.Sulfur isotopic analysis indicatesδ34SV-CDT from 4.4×10-3 to 6.5×10^(-3),with an average of 5.2×10^(-3),whereas H isotopes values onδDV-SMOW standard are-100.8×10^(-3) and-107.5×10^(-3),while O isotopes data onδ18OV-SMOW standard range between 20.1×10^(-3) and 20.4×10-3.Fluid inclusions study,combining with sulfur and H-O isotopic data reveal that the ore-forming fluids originated from deep source and were subsequently contaminated by meteoric water.Hydrostatic pressure calculation shows that the minimum and maximum pressures are 11.65 and 42.33 MPa,and relevant depths of deposit are estimated to be 1.16 and 4.23 km.Finally,we inferred that Qinggouzi stibnite deposit is a medium-low temperature,low salinity hydrothermal deposit,which is formed by deep source and later contaminated by meteoric water,and is classified as epizonal deposit in terms of orogenic series.
文摘We studied the fluid inclusions of the Jiguanshan Mo deposit in China,which is a large porphyry deposit located in the southern Xilamulun Metallogenic Belt.The irregular Mo ore body with various types of hydrothermal veinlets is hosted by Late Jurassic granite porphyry.Intense hydrothermal alterations in the deposit from the core to margin are silicification-potassium feldspar alteration,pyrite-quartz-sericite-fluorite alteration,and propylitic alteration.Based on the mineral assemblages and crosscutting relationships of ore veins,the ore-forming process were divided into three stages and two substages:quartz-pyrite veins(stage I)associated with potassic alteration;quartz-molybdenite-chalcopyrite-pyrite veins(substage Ⅱ-1)and quartz-molybdenite-fluorite veins(substage Ⅱ-2)associated with phyllic alteration;and fluorite-quartz-carbonate veins(stage Ⅲ)with carbonation.Five majorfluid inclusions(FIs)types were distinguished in the quartz associated with oxide and sulfide minerals,i.e.polyphase brine(Pb-type),opaque-bearing brine(Ob-type),solid halite(S-type),two-phase aqueous(A-type),and vapor(Vtype)inclusions.The FIs of stage I were composed of liquid-rich S-,A-,and V-type FIs with homogenization temperatures and salinities of 490 to 511℃ and 8.9 to 56.0 wt%NaCl equiv.,respectively.The FIs of substage Ⅱ-1 are composed of Pb-,Ob-,S-,A-,and V-type FIs with homogenization temperatures and salinities of 352 to 460℃ and 3.7 to 46.1 wt%NaCl equiv,respectively.The FIs of substage Ⅱ-2 are Ob-,S-,A-,and V-type FIs with homogenization temperatures and salinities of 234 to309°C and 3.7 to 39.2 wt%NaCl equiv,respectively.The FIs of stage Ⅲ are A-type FIs with homogenization temperatures and salinities of 136 to 172℃ and 1.1 to 8.9 wt%NaCl equiv,respectively.Fluid boiling,which resulted in the precipitation of sulfides,occurred in stages I andⅡ.The initial ore-forming fluids of the Jiguanshan deposit had high temperature,high salinity,and belonged to an F-rich NaCl±KCl-H2O system.The fluids gradually evolv
