0 INTRODUCTION Sulfur(S)and carbon(C)are essential volatile elements in both interior and surficial systems of the Earth.The cycling of S and C in subduction zones plays a fundamental role in modulating global S-C flu...0 INTRODUCTION Sulfur(S)and carbon(C)are essential volatile elements in both interior and surficial systems of the Earth.The cycling of S and C in subduction zones plays a fundamental role in modulating global S-C fluxes and exerts a significant influence on the climate evolution,mantle's redox budget,and ore deposit formation(Bekaert et al.,2021).展开更多
The Xingyuan large fluorite deposit in Fengning,Hebei Province,China,is a significant deposit in the North Hebei-West Liaoning fluorite mineralization belt.The ore bodies are structurally controlled and occur in fault...The Xingyuan large fluorite deposit in Fengning,Hebei Province,China,is a significant deposit in the North Hebei-West Liaoning fluorite mineralization belt.The ore bodies are structurally controlled and occur in fault zones near granitic porphyry veins.Previous studies have focused on the geology and ore-controlling factors,whereas the general features of the hydrothermal systems that contributed to the formation of the deposit remain unclear.This study investigated the nature,origin,and evolution of mineralizing fluids in the Fengning deposit,based on fluid inclusion and H-O isotope data.The fluid inclusions in fluorite are mostly H2O-rich,gas-liquid,two-phase inclusions,along with a few three-phase inclusions containing halite daughter crystals and CO_(2)gas.The ore-forming fluid was variable in homogenization temperature(108-388°C),salinity(0.2-47.4 wt%NaCl equivalent),and density(0.58-1.11 g/cm^(3)),which indicate it was a H2O-NaCl-CO_(2)system of moderate-low temperature,low salinity,and low density.Fluorite H-O isotopes(δD_(V-SMOW)=−123.5‰to−111.8‰;δ^(18)O_(V-SMOW)=−10.3‰to−6.5‰),temperature data,and fluid compositions indicate the mineralizing fluid was initially dominated by magmatic waters,but then experienced a large influx of meteoric waters.The fluid temperature and salinity decreased and the density increased from the early to late stages of mineralization.The main mechanisms of fluorite precipitation were water-rock reactions and fluid cooling.The Xingyuan fluorite deposit is a post-magmatic hydrothermal deposit.展开更多
0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temper...0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temperature condition of the reservoirs(Meulbroek et al.,1998;Blanc and Connan,1994;Evans et al.,1971).展开更多
The Jalilabad Cu(±Au)deposit lies in the central section of the Tarom-Hashjin Metallogenic Belt,in northern Zanjan Province,NW Iran.Mineralization predominantly occurs within quartz-sulfide veins,veinlets,and bre...The Jalilabad Cu(±Au)deposit lies in the central section of the Tarom-Hashjin Metallogenic Belt,in northern Zanjan Province,NW Iran.Mineralization predominantly occurs within quartz-sulfide veins,veinlets,and breccia zones,primarily hosted by the Eocene volcanic and volcaniclastic units of the Karaj Formation.The mineralization trends NW-SE and is influenced by several strike-slip faults.Chalcopyrite and bornite are the principal hypogene sulfides,with chalcocite and covellite representing the supergene stage.The post-ore stage is characterized by brecciated calcite and quartz.Geochemical analyses show that the monzonite intrusion contains SiO_(2)levels ranging from 69.80 to 70.24 wt.%,K_(2)O+Na_(2)O values between 8.10 and 8.15 wt.%,and K_(2)O/Na_(2)O ratios of 1.36 to 1.61.The intrusion is enriched in light rare earth elements(LREEs)and large-ion lithophile elements(LILEs)while being depleted in high-field-strength elements(HFSEs).A low Hf/Sm ratio indicates an orogenic-related magma,and a low Nb/La ratio points to a depleted mantle source.Microthermometric studies of three quartz types reveal moderate to high formation temperatures(195.4-322.7℃)and salinities ranging from 8.10 to 11.82 wt.%NaCl_(equiv).Oxygen isotope data(δ^(18)O_(H2O)O)range from+4.8‰to+8.1‰,suggesting a magmatic origin for the ore-forming fluids,later diluted by meteoric water.Sulfur isotope values(δ^(34)S_(H2S))between−6.0‰and−9.1‰confirm a magmatic source.Fluid mixing and dilution are identified as the primary mechanisms for ore precipitation.Raman spectroscopy enables nondestructive identification of minerals through their unique vibrational peaks.Chalcopyrite(213,280,1304 cm^(−1)),hematite(214,282,469,689,1309 cm^(−1)),goethite(967 cm^(−1)),and quartz(125,198,458 cm^(−1))show distinct spectral fingerprints indicating mineral differentiation,alteration tracking,and structural analysis in geological studies.Based on its geological context,the Jalilabad Cu(±Au)deposit is interpreted as resembling a high-sulfidation epithermal deposit.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
The characteristics of quartz-hosted fluid inclusions in fluvial sediments from five locations in the upstream,midstream,and estuary of the Changjiang River,China,are analyzed.The sources of sediments are discussed co...The characteristics of quartz-hosted fluid inclusions in fluvial sediments from five locations in the upstream,midstream,and estuary of the Changjiang River,China,are analyzed.The sources of sediments are discussed concerning their differences in the shape,size,number,gas percentage and genetic type of quartz-hosted fluid inclusions.From upstream to downstream,the characteristics of quartz-hosted fluid inclusions in sediments are different.The fluid inclusion types in the samples from upstream to estuary are gradually enriched.The sediment influx from the tributaries of the Changjiang River makes new types of quartz-hosted fluid inclusions in the downstream and estuary.In terms of the number and size,most quartz-hosted fluid inclusions are concentrated in the range of 2-4μm in diameters and 10-150 in number per 10^-3 mm^3.The number and size ranges of the fluid inclusions from different positions are also different.The fluid inclusions in the sample collected from the Shigu,upstream of the Changjiang River,are 2-18μm in size,with the number of 2-166 per 10^-3 mm^3.Among the samples collected from Yibin,Yichang and Wuhan,the sizes of fluid inclusions are 2-15,2-10,2-12μm,with the number of 1-270,2-220,and 1^-308 per 10^-3 mm^3,respectively.The proportion of primary fluid inclusions in the sample of the upstream(14%)is higher than that of the midstream(6%-8%)and the estuary(5%),suggesting that different types of source rocks have been input into the river by the tributaries.The characteristics of quartz-hosted fluid inclusions in the fluvial sediments could offer a new perspective for exploration of the source of sediments.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 evolved to low temperature,low salinity,and belonged to a NaCl-H2O system.Studies of the hydrogen and oxygen isotope compositions of quartz(δ^18OH2O=-7.3 to 6.3%,δDH2O=-104.3 to-83.3%)show that the ore-formingfluids gradually evolved from magmatic water to meteoric water.展开更多
The Huize Zn-Pb- (Ag-Ge) district is a typical representative of the well-known medium-to large-sized carbonate-hosted Zn-Pb- (Ag-Ge) deposits, occurring in the Sichuan-Yunnan-Guizhou Pb-Zn Ore-forming Zone. Generally...The Huize Zn-Pb- (Ag-Ge) district is a typical representative of the well-known medium-to large-sized carbonate-hosted Zn-Pb- (Ag-Ge) deposits, occurring in the Sichuan-Yunnan-Guizhou Pb-Zn Ore-forming Zone. Generally, fluid inclusions within calcite, one of the major gangue minerals, are dominated by two kinds of small (1-10 um) inclusions including pure-liquid and liquid. The inclusions exist in concentrated groups along the crystal planes of the calcite. The ore-forming fluids containing Pb and Zn, which belong to the Na+-K+-Ca2+-Cl--F--SO42- type, are characterized by temperatures of 164-221℃, medium salinity in 5-10.8 wt% NaCl, and medium pressure at 410×105 to 661×105 Pa. The contents of Na+-K+ and C1--F-, and ratios of Na+/K+-Cl-/F- in fluid inclusions present good linearity. The ratios of Na+/K+ (4.66-6.71) and Cl-/F- (18.21-31.04) in the fluid inclusions of calcite are relatively high, while those of Na+/K+ (0.29-5.69) and Cl-/F- (5.00-26.0) in the inclusions of sphalerite and pyrite are relatively low. The ratio of Na+/K+ increases in accord with those of Cl-/F-, which indicates that ore-forming fluid of deep source participates in the mineralization. The waters of fluid inclusions have δD values from -43.5‰ to -55.4‰ of calcite. The δ18OV-SMOW values of the ore-forming fluids, calculated values, range from 17.09‰ to 18.56‰ of calcite and 17.80‰ to 23.14‰ for dolomite. δ13CV-PDB values range from -1.94‰ to -3.31‰ for calcite and -3.35‰ to 0.85‰ for the ore-bearing dolomite. These data better demonstrate that the ore-forming fluids were mainly derived from metamorphic water and magmatic hot fluid, in relation to the metamorphism of the Kunyang Group in the basement and magmatic hydrothermalism. The deposit itself might have resulted from ascending cycles of ore-forming fluid, enriched in Pb and Zn. The Huize Zn-Pb- (Ag-Ge) deposits related to carbonate-hosted Zn-Pb sulphides.展开更多
The recently discovered Damoqujia （大磨曲家） gold deposit is a large shear zone-hosted gold deposit of disseminated sulphides located in the north of the Zhaoping （招平） fault zone, Jiaodong （胶东） gold province...The recently discovered Damoqujia （大磨曲家） gold deposit is a large shear zone-hosted gold deposit of disseminated sulphides located in the north of the Zhaoping （招平） fault zone, Jiaodong （胶东） gold province, China. In order to distinguish the temperature range of cluster inclusions from different mineralization stages and measure their compositions, 16 fluid inclusions and 5 isotopic geochemistry samples were collected for this study. Corresponding to different mineralization stages, the multirange peaks of quartz decrepitation temperature （250-270, 310-360 and 380-430℃） indicate that the activity of ore-forming fluids is characterized by multistage. The ore-forming fluids were predominantly of high-temperature fluid system （HTFS） by CO2-rich, and SO4^2--K^＋ type magmatic fluid during the early stage of mineralization and were subsequently affected by low-temperature fluid system （LTFS） of CH4-rich, and Cl^--Na^＋/Ca^2＋ type meteoric fluid during the late stage of mineralization. Gold is transferred by Au-HS^- complex in the HTFS, and Au-Cl^- complex can be more important in the LTFS. The transition of fluids from deeper to shallow environments results in mixing between the HTFS and LTFS, which might be one of the most key reasons for gold precipitation and large-scale mineralization. The ore-forming fluids are characterized by high-temperature, strong-activity, and superimposed mineralization, so that there is a great probability of forming large and rich ore deposit in the Damoqujia gold deposit. The main bodies are preserved and extend toward deeper parts, thereby suggesting a great potential in future.展开更多
The Bangbu gold deposit is a large orogenic gold deposit in Xizang formed during the AlpineHimalayan collision.Ore bodies(auriferous quartz veins)are controlled by the E-W-trending Qusong-Cuogu-Zhemulang brittle-ducti...The Bangbu gold deposit is a large orogenic gold deposit in Xizang formed during the AlpineHimalayan collision.Ore bodies(auriferous quartz veins)are controlled by the E-W-trending Qusong-Cuogu-Zhemulang brittle-ductile shear zone.Quartz veins at the deposit can be divided into three types:pre-metallogenic hook-like quartz veins,metallogenic auriferous quartz veins,and postmetallogenic N-S quartz veins.Four stages of mineralization in the auriferous quartz veins have been identified:(1)Stage S1 quartz+coarse-grained sulfides,(2)Stage S2 gold+fine-grained sulfides,(3)Stage S3 quartz+carbonates,and(4)Stage S4 quartz+greigite.Fluid inclusions indicate the oreforming fluid was CO_2-N_2-CH_4 rich with homogenization temperatures of 170–261°C,salinities 4.34–7.45 wt%Na Cl equivalent.δ^(18)Ofluid(3.98‰–7.18‰)and lowδDV-SMOW(-90‰to-44‰)for auriferous quartz veins suggest ore-forming fluids were mainly metamorphic in origin,with some addition of organic matter.Quartz vein pyrite hasδ^(34)SV-CDT values of 1.2‰–3.6‰(an average of 2.2‰),whereas pyrite from phyllite hasδ^(34)SV-CDT 5.7‰–9.9‰(an average of 7.4‰).Quartz vein pyrites yield 206Pb/204 Pb ratios of 18.662–18.764,207Pb/204 Pb 15.650–15.683,and^(208)Pb/204 Pb 38.901–39.079.These isotopic data indicate Bangbu ore-forming materials were probably derived from the Langjiexue accretionary wedge.40Ar/39 Ar ages for sericite from auriferous sulfide-quartz veins yield a plateau age of 49.52±0.52 Ma,an isochron age of 50.3±0.31 Ma,suggesting that auriferous veins were formed during the main collisional period of the Xizang-Himalayan orogen(-65–41 Ma).展开更多
He-Ar isotopic compositions of fluid inclusions trapped in pyrites from some representative PGE-polymetallic deposits in Lower Cambrian black rock series in South China were analyzed by using an inert gas isotopic mas...He-Ar isotopic compositions of fluid inclusions trapped in pyrites from some representative PGE-polymetallic deposits in Lower Cambrian black rock series in South China were analyzed by using an inert gas isotopic mass spectrometer. The results show that the ore-forming fluids possess a low 3He/4He ratio, varying from 0.43×10-8 to 26.39×10-8, with corresponding R/Ra value of 0.003-0.189. The 40Ar/36Ar ratios are 258-287, close to those of air saturated water (ASW). He-Ar isotopic indicator studies show that the ore-forming fluids were mainly derived from the formation water or basinal hot brine and sea water, while the content of mantle-derived fluid or deep-derived magmatic water might be negligible. The PGE-polymetallic mineralization might be related to the evolution of the Caledonian miogeosynclines distributed along the southern margin of the Yangtze Craton. During the Early Cambrian, the formation water or basinal hot brine trapped in Caledonian basins which accumulated giant thick sediments was expelled and migrated laterally along strata because of the pressure generated by overlying sediments. The basinal hot brine ascended along faults, mixed with sea water and finally deposited ore minerals.展开更多
The Yinkeng orefield in Yudu County,Jiangxi Province,SE China,is a zone of concentrated Au-Ag-Pb-Zn-Cu-Mn polymetallic ores.Based on summing up basic geology and ore geology of the orefieid,the polymetallic deposits i...The Yinkeng orefield in Yudu County,Jiangxi Province,SE China,is a zone of concentrated Au-Ag-Pb-Zn-Cu-Mn polymetallic ores.Based on summing up basic geology and ore geology of the orefieid,the polymetallic deposits in the orefield have been divided into seven major substyles according to their occurring positions and control factors.The ore-forming fluid inclusion styles in the orefield include those of two-phase fluid,liquid CO2-bearing three-phase and daughter mineral-bearing multi-phase.The homogenization temperatures range from 382° to 122℃,falling into five clusters of 370° to 390°,300° to 360°,230° to 300°,210° to 290° and 120° to 200°,and the clusters of 300° to 360°,230° to 300° and 120° to 200° are three major mineralization stages,with fluid salinity peaks from 4.14% to 7.31%,2.07% to 7.31% and 0.53% to 3.90%,respectively.The ore-forming fluids are mainly type of NaCl-H2O with medium to high density （0.74-1.02 g/cm3）,or CO2-bearing NaCl-H2O with medium to low density （0.18-0.79 g/cm3）.The fluid salinity and density both show a decline tendency with decreasing temperature.According to the measurement and calculation of Hand O-isotopic compositions in the quartz of the quartz-sulfide veins,δDV-SMOW of the ore-forming fluid is from-84‰ to-54‰,and δ18OV-SMOW of that is from 6.75‰ to 9.21‰,indicating a magmatic fluid.The δ34SV-CDT of sulfides in the ores fall into two groups,one is from-4.4‰ to 2.2‰ with average of-1.42‰,and the other from 18.8‰ to 21.6‰ with average of 19.8‰.The S-isotopic data shows one peak at-4.4‰ to 2.2‰ （meaning-1.42‰） suggesting a simple magmatic sulfur source.The ore Pbisotopic ratios are 206pb/204pb from 17.817 to 17.983,207pb/204pb from 15.470 to 15.620 and 208pb/204pb from 38.072 to 38.481,indicating characteristics of mantle-derived lead.The data show that the major ore deposits in the orefield have a magmatic-hydrothermal genesis and that the SHRIMP zircon age of the granodiorite porphyry,closely related to the mineralization,is 151.2±4.2 Ma （MSWD =1.3）,which can represent the formation ages of the ores and intrusion rocks.The study aids understanding of the ore-forming processes of the major metallic ore deposits in the orefield.展开更多
The Mengyejing potash deposit is located in the southern port of the Simao Basin, Yunnan Province, and is hosted in mid-Cretaceous strata. The chemical compositions of fluid inclusions in halite crystals, collected fr...The Mengyejing potash deposit is located in the southern port of the Simao Basin, Yunnan Province, and is hosted in mid-Cretaceous strata. The chemical compositions of fluid inclusions in halite crystals, collected from the level-610 adit in the deposit, were analysed by laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS）. The results show that the brine is of the Na-K-Mg-Ca-Cl type and has K concentrations that are distinctly higher than those of Mg and Ca, unlike normal brines associated with Cretaceous halite. The high K concentrations indicate that the degree of evaporation of the ancient Mengyejing saline lake was very high, reaching the sylvite deposition stage but rarely reaching the carnallite deposition stage. The trajectory of the H and O isotopic compositions of the brines in the halite-hosted fluid inclusions corresponds to intense evaporation, indicating that the net evaporation exceeded the net inflow of brines. These brine compositions in halite-hosted fluid inclusions were likely formed by the dissolution of previously deposited K-bearing minerals by fresh continental and/or seawater, forming a type of modified seawater, with deep hydrothermal fluids potentially supplying additional potassium. The basin likely experienced multiple seawater incursion, dissolution and redeposition events in a high-temperature environment with high evaporation rates.展开更多
Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysi...Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that： （1） up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; （2） high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bcaring CO2 reservoirs that are rich in helium and with a high ^3He/^4He ratio and which show reversed order of 813C in alkane; （3） in gas reservoirs of such abiotic methane （〉80%） and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42 mole%, and the reversed order of δ^13C in alkane is sometimes irregular in the corresponding gas pools; （4） a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4 although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.展开更多
The ore types of the Zhaokalong Fe-Cu deposit are divided into two categories： sulfide-type and oxide-type. The sulfide-type ore include siderite ore, galena-sphalerite ore and chalcopyrite ore, whereas the oxide-typ...The ore types of the Zhaokalong Fe-Cu deposit are divided into two categories： sulfide-type and oxide-type. The sulfide-type ore include siderite ore, galena-sphalerite ore and chalcopyrite ore, whereas the oxide-type ore include magnetite ore and hematite ore. The ore textures and structures indicate that the Zhaokalong deposit is of the sedimentary-exhalative mineralization type. Geochemical analyses show that the two ore types have a high As, Sb, Mn, Co and Ni content. The REE patterns reveal an enrichment of the LREE compared to the HREE. Isotopic analysis of siderite ore reveal that the j13CpDB ranges from -2.01 to 3.34 （%0） whereas the JISOsMow ranges from 6.96 to 18.95 （%0）. The fluid inclusion microthermometry results indicate that homogenization temperatures of fluid inclusions in quartz range from 131 to 181~C, with salinity values of 1.06 to 8.04 wt% NaCI eq. The mineralizing fluid therefore belongs to the low temperature - low salinity system, with a mineralizing solution of a CO2-Ca2＋（Na＋, K＋）-SO42- （F-, CI--H20 system. The geochemical results and fluid inclusion data provide additional evidence that the Zhaokalong deposit is a sedex-type deposit that experienced two stages of mineralization. The sulfide mineralization probably occurred first, during the sedimentary exhalative process, as exhibited by the abundance of marine materials associated with the sulfide ores, indicating a higher temperature and relatively deoxidized oceanic depositional environment. After the main exhalative stage, hydrothermal activity was superimposed to the sulfide mineralization. The later stage oxide mineralization occurred in a low temperature and relatively oxidized environment, in which magmatic fluid circulation was dominant.展开更多
The Tuolugou cobalt deposit is the first independent large-scale Co- and Au-bearing deposit discovered in northwestern China. It is located in the eastern Kunlun orogenic belt in Qinghai Province, and occurs conformab...The Tuolugou cobalt deposit is the first independent large-scale Co- and Au-bearing deposit discovered in northwestern China. It is located in the eastern Kunlun orogenic belt in Qinghai Province, and occurs conformably in low-grade metamorphic volcano-sedimentary rock series with well-developed Na-rich hydrothermal sedimentary rocks and typical hydrothermal sedimentary ore fabrics. Fluid inclusions and isotopic geochemistry studies suggest that cobalt mineralizing fluid is dominated by NaCI-H20 system, accompanied by NaCI-CO2-H20-N2 system responsible for gold mineralization. Massive, banded and disseminated pyrite ores have similar compositions of He and Ar isotopes from the mineralizing fluid, with 3He/4He range between 0.10 to 0.31Ra （averaging 0.21Ra）, and 4~Ar/36Ar between 302 and 569 （averaging 373）, which reflects that Co mineralizing fluids derived dominantly from meteoric water deeply circulating. ~34S values of pyrite approaches to zero （~34S ranging from -4.5%o to ＋1.5%o, centering around -1.8%o to -0.2%o）, reflecting its deep source. Ore lead is characterized by distinctly high radiogenesis, with 2~6pb/2~4pb〉19.279, 2~7pb/2~4pb〉15.691 and 2~spb/2~4pb〉39.627, and its values show an increase trend from country rocks, regional Paleozoic volcanic rocks to ores. This may have suggested that high radiogentic ore Pb derived mainly from country rocks by leaching meteoric water-dominated hydrothermal fluid during its circulation at depth. Cobalt occurs mainly in sulfide phase （such as pyrite）, but cobalt enrichment, and presence and increasing contents of Co-bearing minerals have a positive correlation with metamorphic degree. The Tuolugou deposit and other typical strata-bound Co-Cu-Au deposits have striking similarities in the geological features and metallogenic pattern of primary cobalt. All of them are syngenetic hydrothermal exhalative sedimentation in origin.展开更多
The Kendekeke polymetallic deposit,located in the middle part of the magmatic arc belt of Qimantag on the southwestern margin of the Qaidam Basin,is a polygenetic compound deposit in the Qimantag metallogenic belt of ...The Kendekeke polymetallic deposit,located in the middle part of the magmatic arc belt of Qimantag on the southwestern margin of the Qaidam Basin,is a polygenetic compound deposit in the Qimantag metallogenic belt of Qinghai Province.Multi-periodic ore-forming processes occurred in this deposit,including early-stage iron mineralization and lead-zinc-gold-polymetallic mineralization which was controlled by later hydrothermal process.The characteristics of the ore-forming fluids and mineralization were discussed by using the fluid inclusion petrography,Laser Raman Spectrum and micro-thermometry methods.Three stages,namely,S1-stage （copper-iron-sulfide stage）,S2-stage （lead-zinc-sulfide stage） and C-stage （carbonate stage） were included in the hydrothermal process as indicated by the results of this study.The fluid inclusions are in three types：aqueous inclusion （type I）,CO2-aqueous inclusion （type Ⅱ） and pure CO2 inclusion （type Ⅲ）.Type Ⅰ inclusions were observed in the S1-stage,having homogenization temperature at 240-320℃,and salinities ranging from 19.8％ to 25.0％ （wt％ NaCl equiv.）.All three types of inclusions,existing as immiscible inclusion assemblages,were presented in the S2-stage,with the lowest homogenization temperature ranging from 175 ℃ to 295℃,which represents the metallogenic temperature of the S2-stage.The salinities of these inclusions are in the range of 1.5％ to 16％.The fluid inclusions in the C-stage belong to types Ⅰ,Ⅱ and Ⅲ,having homogenization temperatures at 120-210℃,and salinities ranging from 0.9％ to 14.5％.These observations indicate that the ore-forming fluids evolved from high-temperature to low-temperature,from high-salinity to low-salinity,from homogenization to immiscible separation.Results of Laser Raman Spectroscopy show that high density of CO2 and CH4 were found as gas compositions in the inclusions.CO2,worked as the pH buffer of ore-forming fluids,together with reduction of organic gases （i.e.CH4,etc）,affected the transport and sediment of the minerals.The fluid system alternated between open and close systems,namely,between lithostatic pressure and hydrostatic pressure systems.The calculated metallogenic pressures are in the range of 30 to 87 Mpa corresponding to 3 km mineralization depth.Under the influence of tectonic movements,immiscible separation occurred in the original ore-forming fluids,which were derived from the previous high-salinity,high-temperature magmatic fluids.The separation of CO2 changed the physicochemical properties and composition of the original fluids,and then diluted by mixing with extraneous fluids such as meteoric water and groundwater,and metallogenic materials in the fluids such as lead,zinc and gold were precipitated.展开更多
The Dayingezhuang gold deposit,hosted mainly by Late Jurassic granitoids on Jiaodong Peninsula in eastern China,contains an estimated 170 t of gold and is one of the largest deposits within the Zhaoping fracture zone....The Dayingezhuang gold deposit,hosted mainly by Late Jurassic granitoids on Jiaodong Peninsula in eastern China,contains an estimated 170 t of gold and is one of the largest deposits within the Zhaoping fracture zone.The orebodies consist of auriferous altered pyrite–sericite–quartz granites that show Jiaojia-type(i.e.,disseminated and veinlet)mineralization.Mineralization and alteration are structurally controlled by the NE-to NNE-striking Linglong detachment fault.The mineralization can be divided into four stages:(K-feldspar)–pyrite–sericite–quartz,quartz–gold–pyrite,quartz–gold–polymetallic sulfide,and quartz–carbonate,with the majority of the gold being produced in the second and third stages.Based on a combination of petrography,microthermometry,and laser Raman spectroscopy,three types of fluid inclusion were identified in the vein minerals:NaCl–H2 O(A-type),CO2–H2 O–NaCl(AC-type),and pure CO2(PC-type).Quartz crystals in veinlets that formed during the first stage contain mainly AC-type fluid inclusions,with rare PC-type inclusions.These fluid inclusions homogenize at temperatures of 251°C–403°C and have low salinities of 2.2–9.4 wt%NaCl equivalent.Quartz crystals that formed in the second and third stages contain all three types of fluid inclusions,with total homogenization temperatures of 216°C–339°C and salinities of 1.8–13.8 wt%NaCl equivalent for the second stage and homogenization temperatures of 195°C–321°C and salinities of 1.4–13.3 wt%NaCl equivalent for the third stage.In contrast,quartz crystals that formed in the fourth stage contains mainly A-type fluid inclusions,with minor occurrences of AC-type inclusions;these inclusions have homogenization temperatures of 106°C–287°C and salinities of 0.5–7.7 wt%NaCl equivalent.Gold in the ore-forming fluids may have changed from Au(HS)0 as the dominant species under acidic conditions and at relatively high temperatures and f O2 in the early stages,to Au(HS)2–under neutral-pH conditions at lower temperatures and f O2 in the later stages.The precipitation of gold and other metals is inferred to be caused by a combination of fluid immiscibility and water–rock interaction.展开更多
Recently,volcanic gas reservoirs in Yaoyingtai （腰英台） and Daerhan （达尔罕） tectonic belts in Changling （长岭） faulted depression of southeastern Songliao （松辽） basin have been discovered.Based on the compos...Recently,volcanic gas reservoirs in Yaoyingtai （腰英台） and Daerhan （达尔罕） tectonic belts in Changling （长岭） faulted depression of southeastern Songliao （松辽） basin have been discovered.Based on the compositions and isotopic values,the natural gas is characterized by high content of methane,low content of C2＋,and C1/C1-5 beyond 0.95.Also,the natural gas contains nonhydrocarbons including carbon dioxide with the content from 20% to 40% and minor amount of N2.Combined with the isotopic values,the natural gas is generated by humic kerogen and coal-derived type,but in Daerhan,the natural gas is probably mixed by oil type gas.From the measurement of lithology and fluid inclusions in volcanic rocks,the bitumen,liquid hydrocarbon,and gas hydrocarbon inclusions are present.Through the analysis of the single gas inclusion in volcanic reservoir,the content of carbon dioxide is low,so the carbon dioxide and hydrocarbon gas of the reservoirs are not accumulated at the same time.In addition,minor amount of bitumen in the reservoirs is formed by thermal evolution of the crude oils sourced from the Yingcheng （营城） Formation mudstones through the characterizations of the biomarkers.The distribution of homogenization temperatures presents two peaks,one with the liquid hydrocarbon filling stage,and the other with gas filling stage.However,in Daerhan tectonic belt,the second peak is gas and carbon dioxide mixed filling period probably.Combined with the homogenization temperatures of salt water inclusions,the oil and gas filling period is from Qingshankou （青山口） Formation to Nenjiang （嫩江） Formation in the research area.During the charging period,minor amount of inorganic carbon dioxide filled into the trap,but plenty of inorganic carbon dioxide from the end of Sifangtai （四方台） to Eogene periods was related with the structural movement.展开更多
The Dongjun Pb-Zn-Ag deposit in the northern part of the Great Xing’an Range(NE China)consists of quartzsulfide vein-type and breccia-type mineralization,related to granite porphyry.Hydrothermal alteration is well-de...The Dongjun Pb-Zn-Ag deposit in the northern part of the Great Xing’an Range(NE China)consists of quartzsulfide vein-type and breccia-type mineralization,related to granite porphyry.Hydrothermal alteration is well-developed and includes potassic-silicic-sericitic alteration,phyllic alteration and propylitic alteration.Three stages of mineralization are recognized on the basis of field evidence and petrographic observation,demarcated by assemblages of quartz-pyritearsenopyrite(early stage),quartz-polymetallic sulfide(intermediate stage)and quartz-carbonate-pyrite(late stage).Zircon LA-ICP-MS U-Pb dating indicates that the granite porphyry was emplaced at 146.7±1.2 Ma(Late Jurassic).Microthermometry and laser Raman spectroscopy shows that ore minerals were deposited in conditions of intermediate temperatures(175-359℃),low salinity(0.5-9.3 wt% Na Cl eqv.)and low density(0.60-0.91 g/cm^(3)).Ore-forming fluids were derived largely from magmatic hydrothermal processes,with late-stage addition of meteoric water,belonging to a H_(2)O-NaCl-CO_(2)±CH_(4) system.The δ^(34)SV-CDT values range from 0.75‰ to 4.70‰.The ^(206)Pb/^(204)Pb,^(207)Pb/^(204)Pb,and ^(208)Pb/^(204)Pb values of the ore minerals are in the ranges of 18.240-18.371,15.542-15.570,and 38.100-38.178,respectively.Data for the S and Pb isotopic systems indicate that the ore-forming metals and sulfur were derived from Mesozoic magma.Based on the geological characteristics and geochemical signatures documented in this study,we conclude that the Dongjun deposit is a mesothermal magmatic hydrothermal vein-type Pb-Zn-Ag deposit controlled by fractures and related to granite porphyry,in response to Late Jurassic tectonic-magmatic-hydrothermal activity.We further conclude that fluid immiscibility,fluid mixing and fluid-rock interactions were the dominant mechanisms for deposition of the ore-forming materials.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.92355301,42302061)the China Postdoctoral Science Foundation(No.2023M743471)+1 种基金the Key Research Program of the Institute of Geology and Geophysics,Chinese Academy of Sciences(No.IGGCAS-202204)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y2021026)。
文摘0 INTRODUCTION Sulfur(S)and carbon(C)are essential volatile elements in both interior and surficial systems of the Earth.The cycling of S and C in subduction zones plays a fundamental role in modulating global S-C fluxes and exerts a significant influence on the climate evolution,mantle's redox budget,and ore deposit formation(Bekaert et al.,2021).
基金supported by the National Natural Science Foundation of China(Grant No.41872219).
文摘The Xingyuan large fluorite deposit in Fengning,Hebei Province,China,is a significant deposit in the North Hebei-West Liaoning fluorite mineralization belt.The ore bodies are structurally controlled and occur in fault zones near granitic porphyry veins.Previous studies have focused on the geology and ore-controlling factors,whereas the general features of the hydrothermal systems that contributed to the formation of the deposit remain unclear.This study investigated the nature,origin,and evolution of mineralizing fluids in the Fengning deposit,based on fluid inclusion and H-O isotope data.The fluid inclusions in fluorite are mostly H2O-rich,gas-liquid,two-phase inclusions,along with a few three-phase inclusions containing halite daughter crystals and CO_(2)gas.The ore-forming fluid was variable in homogenization temperature(108-388°C),salinity(0.2-47.4 wt%NaCl equivalent),and density(0.58-1.11 g/cm^(3)),which indicate it was a H2O-NaCl-CO_(2)system of moderate-low temperature,low salinity,and low density.Fluorite H-O isotopes(δD_(V-SMOW)=−123.5‰to−111.8‰;δ^(18)O_(V-SMOW)=−10.3‰to−6.5‰),temperature data,and fluid compositions indicate the mineralizing fluid was initially dominated by magmatic waters,but then experienced a large influx of meteoric waters.The fluid temperature and salinity decreased and the density increased from the early to late stages of mineralization.The main mechanisms of fluorite precipitation were water-rock reactions and fluid cooling.The Xingyuan fluorite deposit is a post-magmatic hydrothermal deposit.
基金supported by the National Natural Science Foundation of China(NSFC)(No.42272169)the efficient exploration and development technologies and integrated demonstration project for deep and ultra-deep carbonate oil and gas reservoirs in the Tarim Basin(No.2025ZD1402301)+1 种基金the Integrated Project of the Joint Fund for Enterprise Innovation and Development of the National Natural Science Foundation of China(No.U24B6001)the Bureau-Level Scientific Research Project of Northwest Oilfield Company(No.KJ202501).
文摘0 INTRODUCTION Gas injection refers to the natural gas charging into pre-existing oil reservoirs,which often leads to notable changes in gas-oil ratio(GOR),oil density,and phase states,depending on the pressure-temperature condition of the reservoirs(Meulbroek et al.,1998;Blanc and Connan,1994;Evans et al.,1971).
文摘The Jalilabad Cu(±Au)deposit lies in the central section of the Tarom-Hashjin Metallogenic Belt,in northern Zanjan Province,NW Iran.Mineralization predominantly occurs within quartz-sulfide veins,veinlets,and breccia zones,primarily hosted by the Eocene volcanic and volcaniclastic units of the Karaj Formation.The mineralization trends NW-SE and is influenced by several strike-slip faults.Chalcopyrite and bornite are the principal hypogene sulfides,with chalcocite and covellite representing the supergene stage.The post-ore stage is characterized by brecciated calcite and quartz.Geochemical analyses show that the monzonite intrusion contains SiO_(2)levels ranging from 69.80 to 70.24 wt.%,K_(2)O+Na_(2)O values between 8.10 and 8.15 wt.%,and K_(2)O/Na_(2)O ratios of 1.36 to 1.61.The intrusion is enriched in light rare earth elements(LREEs)and large-ion lithophile elements(LILEs)while being depleted in high-field-strength elements(HFSEs).A low Hf/Sm ratio indicates an orogenic-related magma,and a low Nb/La ratio points to a depleted mantle source.Microthermometric studies of three quartz types reveal moderate to high formation temperatures(195.4-322.7℃)and salinities ranging from 8.10 to 11.82 wt.%NaCl_(equiv).Oxygen isotope data(δ^(18)O_(H2O)O)range from+4.8‰to+8.1‰,suggesting a magmatic origin for the ore-forming fluids,later diluted by meteoric water.Sulfur isotope values(δ^(34)S_(H2S))between−6.0‰and−9.1‰confirm a magmatic source.Fluid mixing and dilution are identified as the primary mechanisms for ore precipitation.Raman spectroscopy enables nondestructive identification of minerals through their unique vibrational peaks.Chalcopyrite(213,280,1304 cm^(−1)),hematite(214,282,469,689,1309 cm^(−1)),goethite(967 cm^(−1)),and quartz(125,198,458 cm^(−1))show distinct spectral fingerprints indicating mineral differentiation,alteration tracking,and structural analysis in geological studies.Based on its geological context,the Jalilabad Cu(±Au)deposit is interpreted as resembling a high-sulfidation epithermal deposit.
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This study was supported by the National Basic Research Program of China(No.2013CB956504).
文摘The characteristics of quartz-hosted fluid inclusions in fluvial sediments from five locations in the upstream,midstream,and estuary of the Changjiang River,China,are analyzed.The sources of sediments are discussed concerning their differences in the shape,size,number,gas percentage and genetic type of quartz-hosted fluid inclusions.From upstream to downstream,the characteristics of quartz-hosted fluid inclusions in sediments are different.The fluid inclusion types in the samples from upstream to estuary are gradually enriched.The sediment influx from the tributaries of the Changjiang River makes new types of quartz-hosted fluid inclusions in the downstream and estuary.In terms of the number and size,most quartz-hosted fluid inclusions are concentrated in the range of 2-4μm in diameters and 10-150 in number per 10^-3 mm^3.The number and size ranges of the fluid inclusions from different positions are also different.The fluid inclusions in the sample collected from the Shigu,upstream of the Changjiang River,are 2-18μm in size,with the number of 2-166 per 10^-3 mm^3.Among the samples collected from Yibin,Yichang and Wuhan,the sizes of fluid inclusions are 2-15,2-10,2-12μm,with the number of 1-270,2-220,and 1^-308 per 10^-3 mm^3,respectively.The proportion of primary fluid inclusions in the sample of the upstream(14%)is higher than that of the midstream(6%-8%)and the estuary(5%),suggesting that different types of source rocks have been input into the river by the tributaries.The characteristics of quartz-hosted fluid inclusions in the fluvial sediments could offer a new perspective for exploration of the source of sediments.
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 evolved to low temperature,low salinity,and belonged to a NaCl-H2O system.Studies of the hydrogen and oxygen isotope compositions of quartz(δ^18OH2O=-7.3 to 6.3%,δDH2O=-104.3 to-83.3%)show that the ore-formingfluids gradually evolved from magmatic water to meteoric water.
基金the Funds for Fostering Young Pioneers of Yunnan Province(Natural Science Foundation of Yunnan Province)(99D0003G)the National State Climbing Plan(95-Yu-39)+2 种基金the Collaboration Program sponsored by the colleges and universities of Yunnan Province(2000YK-04)the National Natural Science Foundation of China(No.40172038) the Rescarch Project of the Huize Pb-Zn Mine(2000-02).
文摘The Huize Zn-Pb- (Ag-Ge) district is a typical representative of the well-known medium-to large-sized carbonate-hosted Zn-Pb- (Ag-Ge) deposits, occurring in the Sichuan-Yunnan-Guizhou Pb-Zn Ore-forming Zone. Generally, fluid inclusions within calcite, one of the major gangue minerals, are dominated by two kinds of small (1-10 um) inclusions including pure-liquid and liquid. The inclusions exist in concentrated groups along the crystal planes of the calcite. The ore-forming fluids containing Pb and Zn, which belong to the Na+-K+-Ca2+-Cl--F--SO42- type, are characterized by temperatures of 164-221℃, medium salinity in 5-10.8 wt% NaCl, and medium pressure at 410×105 to 661×105 Pa. The contents of Na+-K+ and C1--F-, and ratios of Na+/K+-Cl-/F- in fluid inclusions present good linearity. The ratios of Na+/K+ (4.66-6.71) and Cl-/F- (18.21-31.04) in the fluid inclusions of calcite are relatively high, while those of Na+/K+ (0.29-5.69) and Cl-/F- (5.00-26.0) in the inclusions of sphalerite and pyrite are relatively low. The ratio of Na+/K+ increases in accord with those of Cl-/F-, which indicates that ore-forming fluid of deep source participates in the mineralization. The waters of fluid inclusions have δD values from -43.5‰ to -55.4‰ of calcite. The δ18OV-SMOW values of the ore-forming fluids, calculated values, range from 17.09‰ to 18.56‰ of calcite and 17.80‰ to 23.14‰ for dolomite. δ13CV-PDB values range from -1.94‰ to -3.31‰ for calcite and -3.35‰ to 0.85‰ for the ore-bearing dolomite. These data better demonstrate that the ore-forming fluids were mainly derived from metamorphic water and magmatic hot fluid, in relation to the metamorphism of the Kunyang Group in the basement and magmatic hydrothermalism. The deposit itself might have resulted from ascending cycles of ore-forming fluid, enriched in Pb and Zn. The Huize Zn-Pb- (Ag-Ge) deposits related to carbonate-hosted Zn-Pb sulphides.
基金supported by the National Natural Science Foundation of China (Nos. 40672064, 40572063)the 973-Project (No. 2006CB403506)Changjiang Scholars and Innovative Research Team in University and 111 Project of the Ministry of Education, China (No. B07011)
文摘The recently discovered Damoqujia （大磨曲家） gold deposit is a large shear zone-hosted gold deposit of disseminated sulphides located in the north of the Zhaoping （招平） fault zone, Jiaodong （胶东） gold province, China. In order to distinguish the temperature range of cluster inclusions from different mineralization stages and measure their compositions, 16 fluid inclusions and 5 isotopic geochemistry samples were collected for this study. Corresponding to different mineralization stages, the multirange peaks of quartz decrepitation temperature （250-270, 310-360 and 380-430℃） indicate that the activity of ore-forming fluids is characterized by multistage. The ore-forming fluids were predominantly of high-temperature fluid system （HTFS） by CO2-rich, and SO4^2--K^＋ type magmatic fluid during the early stage of mineralization and were subsequently affected by low-temperature fluid system （LTFS） of CH4-rich, and Cl^--Na^＋/Ca^2＋ type meteoric fluid during the late stage of mineralization. Gold is transferred by Au-HS^- complex in the HTFS, and Au-Cl^- complex can be more important in the LTFS. The transition of fluids from deeper to shallow environments results in mixing between the HTFS and LTFS, which might be one of the most key reasons for gold precipitation and large-scale mineralization. The ore-forming fluids are characterized by high-temperature, strong-activity, and superimposed mineralization, so that there is a great probability of forming large and rich ore deposit in the Damoqujia gold deposit. The main bodies are preserved and extend toward deeper parts, thereby suggesting a great potential in future.
基金funded by the National Basic Research Program of China(No.2011CB403104)Geological Survey Project of China(No.12120113037901)
文摘The Bangbu gold deposit is a large orogenic gold deposit in Xizang formed during the AlpineHimalayan collision.Ore bodies(auriferous quartz veins)are controlled by the E-W-trending Qusong-Cuogu-Zhemulang brittle-ductile shear zone.Quartz veins at the deposit can be divided into three types:pre-metallogenic hook-like quartz veins,metallogenic auriferous quartz veins,and postmetallogenic N-S quartz veins.Four stages of mineralization in the auriferous quartz veins have been identified:(1)Stage S1 quartz+coarse-grained sulfides,(2)Stage S2 gold+fine-grained sulfides,(3)Stage S3 quartz+carbonates,and(4)Stage S4 quartz+greigite.Fluid inclusions indicate the oreforming fluid was CO_2-N_2-CH_4 rich with homogenization temperatures of 170–261°C,salinities 4.34–7.45 wt%Na Cl equivalent.δ^(18)Ofluid(3.98‰–7.18‰)and lowδDV-SMOW(-90‰to-44‰)for auriferous quartz veins suggest ore-forming fluids were mainly metamorphic in origin,with some addition of organic matter.Quartz vein pyrite hasδ^(34)SV-CDT values of 1.2‰–3.6‰(an average of 2.2‰),whereas pyrite from phyllite hasδ^(34)SV-CDT 5.7‰–9.9‰(an average of 7.4‰).Quartz vein pyrites yield 206Pb/204 Pb ratios of 18.662–18.764,207Pb/204 Pb 15.650–15.683,and^(208)Pb/204 Pb 38.901–39.079.These isotopic data indicate Bangbu ore-forming materials were probably derived from the Langjiexue accretionary wedge.40Ar/39 Ar ages for sericite from auriferous sulfide-quartz veins yield a plateau age of 49.52±0.52 Ma,an isochron age of 50.3±0.31 Ma,suggesting that auriferous veins were formed during the main collisional period of the Xizang-Himalayan orogen(-65–41 Ma).
基金the National Natural Sciences Foundation of China(grants40173025,49928201)Trans-century Training Program Foundation for the Talents by the Ministry of Education the Visiting Scholar Foundation of Labs in Universities.
文摘He-Ar isotopic compositions of fluid inclusions trapped in pyrites from some representative PGE-polymetallic deposits in Lower Cambrian black rock series in South China were analyzed by using an inert gas isotopic mass spectrometer. The results show that the ore-forming fluids possess a low 3He/4He ratio, varying from 0.43×10-8 to 26.39×10-8, with corresponding R/Ra value of 0.003-0.189. The 40Ar/36Ar ratios are 258-287, close to those of air saturated water (ASW). He-Ar isotopic indicator studies show that the ore-forming fluids were mainly derived from the formation water or basinal hot brine and sea water, while the content of mantle-derived fluid or deep-derived magmatic water might be negligible. The PGE-polymetallic mineralization might be related to the evolution of the Caledonian miogeosynclines distributed along the southern margin of the Yangtze Craton. During the Early Cambrian, the formation water or basinal hot brine trapped in Caledonian basins which accumulated giant thick sediments was expelled and migrated laterally along strata because of the pressure generated by overlying sediments. The basinal hot brine ascended along faults, mixed with sea water and finally deposited ore minerals.
基金financially supported jointly by the National Key Basic Research Program (Grant 2012CB416704) from the Ministry of Science and Technology, Chinathe Program of High-level Geological Talents (201309) and Youth Geological Talents (201112) from the China Geological Surveyby Geological Survey Program Grant 1212010561603-2 from the China Geological Survey
文摘The Yinkeng orefield in Yudu County,Jiangxi Province,SE China,is a zone of concentrated Au-Ag-Pb-Zn-Cu-Mn polymetallic ores.Based on summing up basic geology and ore geology of the orefieid,the polymetallic deposits in the orefield have been divided into seven major substyles according to their occurring positions and control factors.The ore-forming fluid inclusion styles in the orefield include those of two-phase fluid,liquid CO2-bearing three-phase and daughter mineral-bearing multi-phase.The homogenization temperatures range from 382° to 122℃,falling into five clusters of 370° to 390°,300° to 360°,230° to 300°,210° to 290° and 120° to 200°,and the clusters of 300° to 360°,230° to 300° and 120° to 200° are three major mineralization stages,with fluid salinity peaks from 4.14% to 7.31%,2.07% to 7.31% and 0.53% to 3.90%,respectively.The ore-forming fluids are mainly type of NaCl-H2O with medium to high density （0.74-1.02 g/cm3）,or CO2-bearing NaCl-H2O with medium to low density （0.18-0.79 g/cm3）.The fluid salinity and density both show a decline tendency with decreasing temperature.According to the measurement and calculation of Hand O-isotopic compositions in the quartz of the quartz-sulfide veins,δDV-SMOW of the ore-forming fluid is from-84‰ to-54‰,and δ18OV-SMOW of that is from 6.75‰ to 9.21‰,indicating a magmatic fluid.The δ34SV-CDT of sulfides in the ores fall into two groups,one is from-4.4‰ to 2.2‰ with average of-1.42‰,and the other from 18.8‰ to 21.6‰ with average of 19.8‰.The S-isotopic data shows one peak at-4.4‰ to 2.2‰ （meaning-1.42‰） suggesting a simple magmatic sulfur source.The ore Pbisotopic ratios are 206pb/204pb from 17.817 to 17.983,207pb/204pb from 15.470 to 15.620 and 208pb/204pb from 38.072 to 38.481,indicating characteristics of mantle-derived lead.The data show that the major ore deposits in the orefield have a magmatic-hydrothermal genesis and that the SHRIMP zircon age of the granodiorite porphyry,closely related to the mineralization,is 151.2±4.2 Ma （MSWD =1.3）,which can represent the formation ages of the ores and intrusion rocks.The study aids understanding of the ore-forming processes of the major metallic ore deposits in the orefield.
基金supported by the Basic Research Project for the Central Public Welfare Scientific Institutions of China (No.K1405)the National Key Project for Basic Research of China (No.2011CB403007)the National Natural Science Foundation of China (No.41572067)
文摘The Mengyejing potash deposit is located in the southern port of the Simao Basin, Yunnan Province, and is hosted in mid-Cretaceous strata. The chemical compositions of fluid inclusions in halite crystals, collected from the level-610 adit in the deposit, were analysed by laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS）. The results show that the brine is of the Na-K-Mg-Ca-Cl type and has K concentrations that are distinctly higher than those of Mg and Ca, unlike normal brines associated with Cretaceous halite. The high K concentrations indicate that the degree of evaporation of the ancient Mengyejing saline lake was very high, reaching the sylvite deposition stage but rarely reaching the carnallite deposition stage. The trajectory of the H and O isotopic compositions of the brines in the halite-hosted fluid inclusions corresponds to intense evaporation, indicating that the net evaporation exceeded the net inflow of brines. These brine compositions in halite-hosted fluid inclusions were likely formed by the dissolution of previously deposited K-bearing minerals by fresh continental and/or seawater, forming a type of modified seawater, with deep hydrothermal fluids potentially supplying additional potassium. The basin likely experienced multiple seawater incursion, dissolution and redeposition events in a high-temperature environment with high evaporation rates.
文摘Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that： （1） up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; （2） high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bcaring CO2 reservoirs that are rich in helium and with a high ^3He/^4He ratio and which show reversed order of 813C in alkane; （3） in gas reservoirs of such abiotic methane （〉80%） and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42 mole%, and the reversed order of δ^13C in alkane is sometimes irregular in the corresponding gas pools; （4） a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4 although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.
基金supported by the China Schorlarship Council (CSC)the Global Center of Excellence (GCOE) in Novel Carbon Resource Sciences, Kyushu Universitysupported by the Zhaokalong Mine, Qinghai, China
文摘The ore types of the Zhaokalong Fe-Cu deposit are divided into two categories： sulfide-type and oxide-type. The sulfide-type ore include siderite ore, galena-sphalerite ore and chalcopyrite ore, whereas the oxide-type ore include magnetite ore and hematite ore. The ore textures and structures indicate that the Zhaokalong deposit is of the sedimentary-exhalative mineralization type. Geochemical analyses show that the two ore types have a high As, Sb, Mn, Co and Ni content. The REE patterns reveal an enrichment of the LREE compared to the HREE. Isotopic analysis of siderite ore reveal that the j13CpDB ranges from -2.01 to 3.34 （%0） whereas the JISOsMow ranges from 6.96 to 18.95 （%0）. The fluid inclusion microthermometry results indicate that homogenization temperatures of fluid inclusions in quartz range from 131 to 181~C, with salinity values of 1.06 to 8.04 wt% NaCI eq. The mineralizing fluid therefore belongs to the low temperature - low salinity system, with a mineralizing solution of a CO2-Ca2＋（Na＋, K＋）-SO42- （F-, CI--H20 system. The geochemical results and fluid inclusion data provide additional evidence that the Zhaokalong deposit is a sedex-type deposit that experienced two stages of mineralization. The sulfide mineralization probably occurred first, during the sedimentary exhalative process, as exhibited by the abundance of marine materials associated with the sulfide ores, indicating a higher temperature and relatively deoxidized oceanic depositional environment. After the main exhalative stage, hydrothermal activity was superimposed to the sulfide mineralization. The later stage oxide mineralization occurred in a low temperature and relatively oxidized environment, in which magmatic fluid circulation was dominant.
基金supported by grant no K090 1 from the Scientific Research Fund of the China Central Non-Commercial Institutethe Program of Excellent Young Scientists from the Ministry of Land and Resources(200809)+1 种基金grant No40302019 from the National Natural Science Foundation of ChinaGeological Survey Program Grant 1212011085528 from the China Geological Survey
文摘The Tuolugou cobalt deposit is the first independent large-scale Co- and Au-bearing deposit discovered in northwestern China. It is located in the eastern Kunlun orogenic belt in Qinghai Province, and occurs conformably in low-grade metamorphic volcano-sedimentary rock series with well-developed Na-rich hydrothermal sedimentary rocks and typical hydrothermal sedimentary ore fabrics. Fluid inclusions and isotopic geochemistry studies suggest that cobalt mineralizing fluid is dominated by NaCI-H20 system, accompanied by NaCI-CO2-H20-N2 system responsible for gold mineralization. Massive, banded and disseminated pyrite ores have similar compositions of He and Ar isotopes from the mineralizing fluid, with 3He/4He range between 0.10 to 0.31Ra （averaging 0.21Ra）, and 4~Ar/36Ar between 302 and 569 （averaging 373）, which reflects that Co mineralizing fluids derived dominantly from meteoric water deeply circulating. ~34S values of pyrite approaches to zero （~34S ranging from -4.5%o to ＋1.5%o, centering around -1.8%o to -0.2%o）, reflecting its deep source. Ore lead is characterized by distinctly high radiogenesis, with 2~6pb/2~4pb〉19.279, 2~7pb/2~4pb〉15.691 and 2~spb/2~4pb〉39.627, and its values show an increase trend from country rocks, regional Paleozoic volcanic rocks to ores. This may have suggested that high radiogentic ore Pb derived mainly from country rocks by leaching meteoric water-dominated hydrothermal fluid during its circulation at depth. Cobalt occurs mainly in sulfide phase （such as pyrite）, but cobalt enrichment, and presence and increasing contents of Co-bearing minerals have a positive correlation with metamorphic degree. The Tuolugou deposit and other typical strata-bound Co-Cu-Au deposits have striking similarities in the geological features and metallogenic pattern of primary cobalt. All of them are syngenetic hydrothermal exhalative sedimentation in origin.
基金supported by the China Geological Survey Investigation Programs (No. 2008-21-03 and No. 20110301-64)
文摘The Kendekeke polymetallic deposit,located in the middle part of the magmatic arc belt of Qimantag on the southwestern margin of the Qaidam Basin,is a polygenetic compound deposit in the Qimantag metallogenic belt of Qinghai Province.Multi-periodic ore-forming processes occurred in this deposit,including early-stage iron mineralization and lead-zinc-gold-polymetallic mineralization which was controlled by later hydrothermal process.The characteristics of the ore-forming fluids and mineralization were discussed by using the fluid inclusion petrography,Laser Raman Spectrum and micro-thermometry methods.Three stages,namely,S1-stage （copper-iron-sulfide stage）,S2-stage （lead-zinc-sulfide stage） and C-stage （carbonate stage） were included in the hydrothermal process as indicated by the results of this study.The fluid inclusions are in three types：aqueous inclusion （type I）,CO2-aqueous inclusion （type Ⅱ） and pure CO2 inclusion （type Ⅲ）.Type Ⅰ inclusions were observed in the S1-stage,having homogenization temperature at 240-320℃,and salinities ranging from 19.8％ to 25.0％ （wt％ NaCl equiv.）.All three types of inclusions,existing as immiscible inclusion assemblages,were presented in the S2-stage,with the lowest homogenization temperature ranging from 175 ℃ to 295℃,which represents the metallogenic temperature of the S2-stage.The salinities of these inclusions are in the range of 1.5％ to 16％.The fluid inclusions in the C-stage belong to types Ⅰ,Ⅱ and Ⅲ,having homogenization temperatures at 120-210℃,and salinities ranging from 0.9％ to 14.5％.These observations indicate that the ore-forming fluids evolved from high-temperature to low-temperature,from high-salinity to low-salinity,from homogenization to immiscible separation.Results of Laser Raman Spectroscopy show that high density of CO2 and CH4 were found as gas compositions in the inclusions.CO2,worked as the pH buffer of ore-forming fluids,together with reduction of organic gases （i.e.CH4,etc）,affected the transport and sediment of the minerals.The fluid system alternated between open and close systems,namely,between lithostatic pressure and hydrostatic pressure systems.The calculated metallogenic pressures are in the range of 30 to 87 Mpa corresponding to 3 km mineralization depth.Under the influence of tectonic movements,immiscible separation occurred in the original ore-forming fluids,which were derived from the previous high-salinity,high-temperature magmatic fluids.The separation of CO2 changed the physicochemical properties and composition of the original fluids,and then diluted by mixing with extraneous fluids such as meteoric water and groundwater,and metallogenic materials in the fluids such as lead,zinc and gold were precipitated.
基金jointly supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant no.XDA20070304)the China Geological Survey(DD20160024 and grant no.121201102000150011)+1 种基金the China Postdoctoral Science Foundation funded project(Grant no.2016M590119)the National Natural Science Foundation of China(Grant no.41320104004,41602084)
文摘The Dayingezhuang gold deposit,hosted mainly by Late Jurassic granitoids on Jiaodong Peninsula in eastern China,contains an estimated 170 t of gold and is one of the largest deposits within the Zhaoping fracture zone.The orebodies consist of auriferous altered pyrite–sericite–quartz granites that show Jiaojia-type(i.e.,disseminated and veinlet)mineralization.Mineralization and alteration are structurally controlled by the NE-to NNE-striking Linglong detachment fault.The mineralization can be divided into four stages:(K-feldspar)–pyrite–sericite–quartz,quartz–gold–pyrite,quartz–gold–polymetallic sulfide,and quartz–carbonate,with the majority of the gold being produced in the second and third stages.Based on a combination of petrography,microthermometry,and laser Raman spectroscopy,three types of fluid inclusion were identified in the vein minerals:NaCl–H2 O(A-type),CO2–H2 O–NaCl(AC-type),and pure CO2(PC-type).Quartz crystals in veinlets that formed during the first stage contain mainly AC-type fluid inclusions,with rare PC-type inclusions.These fluid inclusions homogenize at temperatures of 251°C–403°C and have low salinities of 2.2–9.4 wt%NaCl equivalent.Quartz crystals that formed in the second and third stages contain all three types of fluid inclusions,with total homogenization temperatures of 216°C–339°C and salinities of 1.8–13.8 wt%NaCl equivalent for the second stage and homogenization temperatures of 195°C–321°C and salinities of 1.4–13.3 wt%NaCl equivalent for the third stage.In contrast,quartz crystals that formed in the fourth stage contains mainly A-type fluid inclusions,with minor occurrences of AC-type inclusions;these inclusions have homogenization temperatures of 106°C–287°C and salinities of 0.5–7.7 wt%NaCl equivalent.Gold in the ore-forming fluids may have changed from Au(HS)0 as the dominant species under acidic conditions and at relatively high temperatures and f O2 in the early stages,to Au(HS)2–under neutral-pH conditions at lower temperatures and f O2 in the later stages.The precipitation of gold and other metals is inferred to be caused by a combination of fluid immiscibility and water–rock interaction.
基金supported by East China Branch of SINOPEC (No. G1414-06-KK-0230)
文摘Recently,volcanic gas reservoirs in Yaoyingtai （腰英台） and Daerhan （达尔罕） tectonic belts in Changling （长岭） faulted depression of southeastern Songliao （松辽） basin have been discovered.Based on the compositions and isotopic values,the natural gas is characterized by high content of methane,low content of C2＋,and C1/C1-5 beyond 0.95.Also,the natural gas contains nonhydrocarbons including carbon dioxide with the content from 20% to 40% and minor amount of N2.Combined with the isotopic values,the natural gas is generated by humic kerogen and coal-derived type,but in Daerhan,the natural gas is probably mixed by oil type gas.From the measurement of lithology and fluid inclusions in volcanic rocks,the bitumen,liquid hydrocarbon,and gas hydrocarbon inclusions are present.Through the analysis of the single gas inclusion in volcanic reservoir,the content of carbon dioxide is low,so the carbon dioxide and hydrocarbon gas of the reservoirs are not accumulated at the same time.In addition,minor amount of bitumen in the reservoirs is formed by thermal evolution of the crude oils sourced from the Yingcheng （营城） Formation mudstones through the characterizations of the biomarkers.The distribution of homogenization temperatures presents two peaks,one with the liquid hydrocarbon filling stage,and the other with gas filling stage.However,in Daerhan tectonic belt,the second peak is gas and carbon dioxide mixed filling period probably.Combined with the homogenization temperatures of salt water inclusions,the oil and gas filling period is from Qingshankou （青山口） Formation to Nenjiang （嫩江） Formation in the research area.During the charging period,minor amount of inorganic carbon dioxide filled into the trap,but plenty of inorganic carbon dioxide from the end of Sifangtai （四方台） to Eogene periods was related with the structural movement.
基金financially supported by the National Natural Science Foundation of China(Grant No.41372098)。
文摘The Dongjun Pb-Zn-Ag deposit in the northern part of the Great Xing’an Range(NE China)consists of quartzsulfide vein-type and breccia-type mineralization,related to granite porphyry.Hydrothermal alteration is well-developed and includes potassic-silicic-sericitic alteration,phyllic alteration and propylitic alteration.Three stages of mineralization are recognized on the basis of field evidence and petrographic observation,demarcated by assemblages of quartz-pyritearsenopyrite(early stage),quartz-polymetallic sulfide(intermediate stage)and quartz-carbonate-pyrite(late stage).Zircon LA-ICP-MS U-Pb dating indicates that the granite porphyry was emplaced at 146.7±1.2 Ma(Late Jurassic).Microthermometry and laser Raman spectroscopy shows that ore minerals were deposited in conditions of intermediate temperatures(175-359℃),low salinity(0.5-9.3 wt% Na Cl eqv.)and low density(0.60-0.91 g/cm^(3)).Ore-forming fluids were derived largely from magmatic hydrothermal processes,with late-stage addition of meteoric water,belonging to a H_(2)O-NaCl-CO_(2)±CH_(4) system.The δ^(34)SV-CDT values range from 0.75‰ to 4.70‰.The ^(206)Pb/^(204)Pb,^(207)Pb/^(204)Pb,and ^(208)Pb/^(204)Pb values of the ore minerals are in the ranges of 18.240-18.371,15.542-15.570,and 38.100-38.178,respectively.Data for the S and Pb isotopic systems indicate that the ore-forming metals and sulfur were derived from Mesozoic magma.Based on the geological characteristics and geochemical signatures documented in this study,we conclude that the Dongjun deposit is a mesothermal magmatic hydrothermal vein-type Pb-Zn-Ag deposit controlled by fractures and related to granite porphyry,in response to Late Jurassic tectonic-magmatic-hydrothermal activity.We further conclude that fluid immiscibility,fluid mixing and fluid-rock interactions were the dominant mechanisms for deposition of the ore-forming materials.
