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1.
Physicochemical parameters of mineralization such as temperature, pressure, salinity, density, composition and boiling of ore fluids as well as pH, Eh, fo2 and reducing parameter in theprocess of mineralization of major ore deposits in the study district have been obtained by the authors through systematic observation and determination of characteristics and phase changes of fluid inclusions at different temperatures and analysis of gaseous and liquid phase compositions of the inclusions, thus providing a scientific basis for the division of mineralization-alteration stages, types of mineral deposits and minerogenetic series and the deepening of the knowledge about the ore-forming processes and mechanisms of mineral deposits. It is indicated that the deposits of the same type have similar fluid inclusion geochemical features and physicochemical parameters though they belong to different minerogenetic series, while the compositions of inclusions are not conditioned by deposit types but closely related to  相似文献   

2.
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℃(2) 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 SO2-4-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 /Ca2 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.  相似文献   

3.
The Dahutang tungsten polymetallic ore field is located north of the Nanling W-Sn polymetallic metallogenic belt and south of the Middle—Lower Yangtze River Valley Cu-Mo-Au-Fe porphyry-skarn belt.It is a newly discovered ore field,and probably represents the largest tungsten mineralization district in the world.The Shimensi deposit is one of the mineral deposits in the Dahutang ore field,and is associated with Yanshanian granites intruding into a Neoproterozoic granodiorite batholith.On the basis of geologic studies,this paper presents new petrographic,microthermometric,laser Raman spectroscopic and hydrogen and oxygen isotopic studies of fluid inclusions from the Shimensi deposit.The results show that there are three types of fluid inclusions in quartz from various mineralization stages:liquid-rich two-phase fluid inclusions,vapor-rich two-phase fluid inclusions,and three-phase fluid inclusions containing a solid crystal,with the vast majority being liquid-rich two-phase fluid inclusions.In addition,melt and melt-fluid inclusions were also found in quartz from pegmatoid bodies in the margin of the Yanshanian intrusion.The homogenization temperatures of liquid-rich two-phase fluid inclusions in quartz range from 162 to 363℃ and salinities are 0.5wt%-9.5wt%NaCI equivalent.From the early to late mineralization stages,with the decreasing of the homogenization temperature,the salinity also shows a decreasing trend.The ore-forming fluids can be approximated by a NaCl-H_2O fluid system,with small amounts of volatile components including CO_2,CH_4 and N_2,as suggested by Laser Raman spectroscopic analyses.The hydrogen and oxygen isotope data show that δ5D_(V-smow) values of bulk fluid inclusions in quartz from various mineralization stages vary from-63.8‰ to-108.4‰,and the δ~(18)O_(H2O) values calculated from the δ~(18)O_(V-)smow values of quartz vary from-2.28‰ to 7.21‰.These H-O isotopic data are interpreted to indicate that the ore-forming fluids are mainly composed of magmatic water in the early stage,and meteoric water was added and participated in mineralization in the late stage.Integrating the geological characteristics and analytical data,we propose that the ore-forming fluids of the Shimensi deposit were mainly derived from Yanshanian granitic magma,the evolution of which resulted in highly differentiated melt,as recorded by melt and melt-fluid inclusions in pegmatoid quartz,and high concentrations of metals in the fluids.Cooling of the ore-forming fluids and mixing with meteoric water may be the key factors that led to mineralization in the Dahutang tungsten polymetallic ore field.  相似文献   

4.
Gold deposits of the meso-epithermal carbonate type were first proposed based on the study of the Baguamiao gold deposit.This new type of gold deposits has many unique characteristics as follows:(1)Obviously strata-bound.The gold deposits are hosted in Middle Devonian turbidite formations;(2)Structrually controlled.Struc-ture is an important factor leading to metallogenesis of this type of gold deposits.The shape and distribution of orebodies are controlled by byittle-ductile shear zones;(3)Multi-stage wall-rock alteration.According to the characteristics of mineral assemblage,gold mineralization can be classified into three stages in association with various wall-rock al-terations.Wall-rock alterations closely genetically related to the gold mineralization are ankerization ,silicification,pyrrhotization and pyritization ;(4)Mineral compositions of the orebodies are mainly pyrrhotite,pyrite,marcasitolite,chalcopyrite,quartz,ankerite,and sericite.Gold mineralization is associated closely in space and time with iron sulfides;(5)Rare elements and REE in ores are low in contents relative to those of the crust.Au content varies from 1.91g/t to 11.15g/t ,averaging 5.5g/t;(6)Studies of sulfur,hydrogen,oxygen and carbon isotopes in main gangue minerals (quartz and ankerite)indicate that fluids and ore-forming materials came from deep-seated sources;(7)Three types of inclusions are recognized in terms of their composition and the vapor amounts of inclusions.The homogenization temperatures of inclusions range from 210℃to 310℃,averaging 230℃,showing that this type of gold deposits belongs to the meso-epithermal type;(8)Metallogenic age of this type of gold deposits is similar to that of the collision between the Yangtze Plate and the North China Plate,indicating that gold deposits of this type are genetically related to continental-margin plate activity.  相似文献   

5.
The Datuanshan deposit is one of the largest and most representative stratabound copper deposits in the Tongling area,the largest ore district in the Middle-Lower Yangtze River metallogenic belt.The location of the orebodies is controlled by the interlayer-slipping faults between the Triassic and Permian strata,and all the orebodies are distributed in stratiform shape around the Mesozoic quartz monzodiorite dikes.Based on field evidence and petrographic observations,four mineralization stages in the Datuanshan deposit have been identified:the skarn,early quartz-sulfide,late quartzsulfide and carbonate stages.Chalcopytite is the main copper mineral and mainly formed at the late quartz-sulfide stage.Fluid inclusions at different stages were studied for petrography,microthermometry,laser Raman spectrometry and stable isotopes.Four types of fluid inclusions,including three-phase fluid inclusions(type 1),liquid-rich fluid inclusions(type 2),vapour-rich fluid inclusions(type 3) and pure vapour fluid inclusions(type 4),were observed.The minerals from the skarn,early and late quartz-sulfide stages contain all fluid inclusion types,but only type 2 fluid inclusions were observed at the carbonate stage.Petrographic observations suggest that most of the inclusions studied in this paper are likely primary.The coexistence of different types of fluid inclusions with contrasting homogenization characteristics(to the liquid and vapour phase,respectively) and similar homogenization temperatures(the modes are 440-480℃,380-400℃ and 280-320℃ for the skarn,early and late quartz-sulfide stages,respectively) in the first three stages,strongly suggests that three episodes of fluid boiling occurred during these stages,which is supported by the hydrogen isotope data.Laser Raman spectra identified CH_4 at the skarn and early quartz-sulfide stages.Combined with other geological features,the early ore-forming fluids were inferred to be under a relatively reduced environment.The CO_2 component has been identified at the late quartz-sulfide and carbonate stages,indicating that the late ore-forming fluids were under a relatively oxidized environment,probably as a result of inflow of and mixing with meteoric water.In addition,microthermometric results of fluid inclusions and H-O isotope data mdicate that the ore forming fluids were dominated by magmatic water in the early stages(skarn and early quartz-sulfide stages) and mixed with meteoric water in the late stages(late quartz-sulfide and carbonate stages).The evidence listed above suggests that the chalcopyrite deposition in the Datuanshan deposit probably resulted from the combination of multiepisode fluid boiling and mixing of magmatic and meteoric water.  相似文献   

6.
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 240–320oC, 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 oC to 295oC, 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 120–210oC, and salinities ranging from 0.9% to 14.5%. These observations indicate that the ore-forming fluids evolved from high-temperature to lowtemperature, 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 highsalinity, 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.  相似文献   

7.
TheWulong lode deposit contains over 80 tonnes of gold with an average grade of 5.35 g/t.It is one of the largest deposits in Dandong City,Liaoning Province in northeast China.Previous studies on the deposit focused on its geological characteristics,geochemistry,fluid inclusions,and the timing of gold mineralization.However,controversy remains regarding the origin of the ore-forming fluids and metals,and the genesis of the gold deposit.This paper presents zircon UePb and pyrite RbeSr ages and S,Pb,He,and Ar isotopic results along with quartz H and O isotopic data for all litho-units associated with the deposit.Laser ablation inductively coupled mass spectrometry measurements yielded zircon UePb dates for samples of pre-mineralization rocks like granite porphyry dike,the Sanguliu granodiorite,fine-grained diorite,and syn-mineralization diorite,as well as post-mineralization dolerite,and lamprophyre;their emplacement ages are 1261 Ma,1241 Ma,1231 Ma,1201 Ma,1192 Ma,and 1152 Ma,respectively.The pyrite RbeSr isochron age is 1191 Ma,indicating that both magmatism and mineralization occurred during the Early Cretaceous.The d18OH2O values of ore-forming hydrothermal fluids from the quartzepolymetallic sulfide vein stage vary from 4.8&to 6.5&,and the dDV-SMOW values are between67.7&and75.9&,indicating that the ore-forming fluids were primarily magmatic.The noble gas isotope compositions of fluid inclusions hosted in pyrite suggest that the ore-forming fluids were dominantly derived from crustal sources with minor mantle input.Sulfur isotopic values of pyrite vary between 0.2&and 3.5&,suggesting that S was derived from a homogeneous magmatic source or possibly from fluids derived from the crust.The Pb isotopic compositions of sulfides(207Pb/204Pb?15.51 e15.71,206Pb/204Pb?17.35e18.75,208Pb/204Pb?38.27e40.03)indicate that the Pb of the Wulong gold deposit is a mixture of crust and mantle components.Geochronological and geochemical data,together with the regional geological history,indicate that Early Cretaceous magmatism and mineralization of the Wulong gold deposit occurred during the rollback of the subducting Paleo-Pacific Plate,which resulted in lithospheric thinning and the destruction of the North China Craton(NCC),which indicates that the deposit is of magmaticehydrothermal origin.  相似文献   

8.
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 δ18OH2O 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.  相似文献   

9.
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–H2O (A-type), CO2–H2O–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 fO2 in the early stages, to Au(HS)2– under neutral-pH conditions at lower temperatures and fO2 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.  相似文献   

10.
Fluid inclusions in quartz from the Lannigou and Yata Carlin-type gold deposits in southwestern Guizhou were analyzed by inductively coupled plasma-mass spectrometry for their trace elements(Co,Ni,Cu,Pb,Zn,Pt,etc.).The results show that quartz fluid inclusions entrapped at different ore-forming stages contain higher Co,Ni,Cu,Pb and Zn.It has been found for the first time that the ore-forming fluids responsible for the Carlin-type gold deposits are rich in Pt.From this it can be concluded that basic volcanic rocks seem to be one of the important sources of ore-forming materials for the Carlin-type gold deposits.  相似文献   

11.
小土尔根铜矿位于新疆阿尔泰地区诺尔特Au-Pb-Zn(-W-Mo)成矿带北部,成矿条件有利。在详细的野外考察基础上,作者系统分析了矿区的流体包裹体类型、流体成分,结合H-O、Cu同位素地球化学研究,对其成矿流体特征及来源、成矿物质来源和矿床成因进行了探讨。该矿流体包裹体类型比较简单,主要为气液两相包裹体,少量纯液相包裹体,偶见含子晶包裹体。激光拉曼光谱分析表明,成矿流体为H_2O-Na Cl-CO_2-CH_4体系。成矿流体温度介于188~421℃,盐度介于0.71%~15.53%Na Cl_(eqv),主要集中于8.0%~12.0%Na Cl_(eqv),为中?高温、中?低盐度成矿流体。H、O同位素(δD_(SMOW)值介于-72‰~-122‰,δ~(18)O_(fluid)值介于3.7‰~8.1‰)指示,成矿流体主要来源于岩浆水,随着成矿作用的进行,大气降水混入的比例略有增大。黄铜矿的δ~(65)Cu值介于-0.12‰~0.93‰,落入花岗岩δ~(65)Cu值分布范围,且分馏特征与花岗岩相似,说明成矿元素Cu来自花岗岩岩浆。结合前人成果,作者认为小土尔根铜矿应为诺尔特地区首例还原性斑岩铜矿床。  相似文献   

12.
三岔金矿位于中祁连新元古代-早古生代中晚期岩浆弧带,是一个陆块与岩浆弧叠置的构造单元。本文在详细的野外矿床地质研究的基础上,开展了与金成矿密切相关的各期流体包裹体岩相学、显微测温、包裹体成分的LRM、碳-氢-氧同位素等方面的分析对比研究工作。结果表明：早期成矿阶段的隐爆石英角砾岩流体包裹体发育气液两相、含子矿物三相和富液相CO2包裹体,均一温度集中于200~280℃,盐度（w（NaCl））集中于6.00%~18.00%,密度集中于0.64~0.73 g/cm3;主成矿阶段的黄铁绢英岩主要发育气液两相包裹体,均一温度集中于160~240℃,盐度为2.00%~6.00%,密度为0.80~0.95 g/cm3;晚期的石英脉阶段主要发育气液两相包裹体,均一温度主要集中在120~190℃,盐度为2.00%~6.00%,密度为0.76~0.86 g/cm3。碳-氢-氧同位素组成揭示三岔矿床的成矿流体早期主要以岩浆水为主,至演化后期,成矿流体有大气水加入;硫同位素研究反映了成矿物质深源性特征。因此,认为三岔矿床属中温热液脉型矿床。  相似文献   

13.
耿庄金矿床产于燕山期隐爆角砾岩体内,是晋东北具有代表意义的金多金属矿床之一。对矿床流体包裹体系统研究表明,不同成矿阶段石英中流体包裹体主要有5种类型：富气相包裹体、富液相包裹体、含CO2三相包裹体、含子矿物三相包裹体及少量纯液相包裹体,流体属H2O-CO2-NaCl体系类型。成矿前阶段包裹体类型多样,且以相似的均一温度共存,显示流体具明显沸腾及不混溶特性;成矿温度集中于170～180 ℃。结合同位素和金矿物特征,认为耿庄金矿床应为与燕山期次火山热液有关的中-低温热液型金矿床。  相似文献   

14.
黑龙江省铜山斑岩铜矿床流体包裹体研究   总被引：14，自引：4，他引：10  
武广  刘军  钟伟  朱明田  糜梅  万秋 《岩石学报》2009,25(11):2995-3006
铜山大型铜矿床位于小兴安岭西北部,是中亚-兴蒙造山带北东段最著名的斑岩型铜矿床之一,矿体产于加里东期花岗闪长岩和中奥陶世多宝山组安山岩、凝灰岩中,铜矿化与硅化-绢云母化关系密切.流体包裹体研究表明,铜山铜矿床主要发育气液两相包裹体、含CO_2包裹体和含子矿物多相包裹体.成矿流体在形成过程中经历了早、中、晚3个阶段的演化.成矿早阶段发育气液两相水溶液包裹体和少量含子矿物多相包裹体,均一温度介于420℃～＞5500C之间,流体盐度介于13.72 wt%～59.76 wt%NaCl eqv之间;中阶段为铜山矿床的主成矿阶段,发育气液两相水溶液包裹体和含CO_2包裹体,均一温度为241℃～417℃,流体盐度介于2.96 wt%～14.04 wt%NaCl eqv之间,主成矿期成矿流体总体上属H_2O-CO_2-NaCl体系;晚阶段仅发育气液两相水溶液包裹体,均一温度为122℃～218℃,盐度介于3.71 wt%～15.96 wt%NaCl eqv之间,表明晚阶段有大气降水的混入.成矿早、中阶段的流体均为不混溶流体,流体沸腾作用是金属硫化物大量沉淀的主要机制.铜山矿床形成于陆缘弧环境.  相似文献   

15.
胶东金矿床碳酸盐矿物的碳-氧和锶-钕同位素地球化学研究   总被引：16，自引：8，他引：16  
对胶东四类金矿床(盆地边缘砾岩型、斑岩型-浅成热液型、石英脉型和破碎带蚀变岩型)矿石中的碳酸盐矿物开展了系统的碳-氧同位素和锶-钕同位素地球化学研究。研究结果表明，与宏观的成矿地质条件和矿床地质特征相对应，山东金矿床可能有亲岩浆岩和亲沉积盆地两个不同的成矿系统。前者包括斑岩型-浅成热液型、石英脉型和破碎带蚀变岩型三类金矿床，后者指盆地边缘砾岩型金矿床，二者具有不同的碳-氧和锶-钕同位素地球化学特征。山东亲岩浆岩系列的金矿床，其锶-钕同位素与同时代的幔源岩浆岩一致，碳同位素显示幔源碳和岩浆碳的特征，氧同位素则显示初生水与大气降水不同比例混合的可能性，因此有可能是以CO2为主、富合成矿金属的地幔流体与浅部下渗大气降水相互作用的结果。而与岩浆岩关系不密切、主要受盆地边缘断裂控制的盆地边缘砾岩型金矿床，其碳-氧和锶-钕同位素组成均较分散，可能主要与地壳浅部下渗大气降水对上地壳各种岩石淋滤萃取演化而成的成矿流体有关。  相似文献   

16.
西藏拉屋铜多金属矿床产于冈底斯构造岩浆成矿带的申扎—旁多铜-银-铅-锌-金成矿亚带内。分别对干矽卡岩阶段(Ⅰ)的石榴石、早期硫化物阶段(Ⅲ)的石英和晚期硫化物阶段(Ⅳ)的方解石中的流体包裹体进行岩相学观察和显微测温研究,研究表明成矿各阶段热液矿物中的流体包裹体主要为气液水两相包裹体,其次为纯液相水包裹体,偶见气液两相甲烷包裹体,石英中也有大量的含NaCl子矿物多相包裹体,其均一温度变化于95～476℃之间,盐度介于1.57%～37.33%,密度变化于0.68～1.23 g/cm3,总体属中-高温、中-高盐度、中等密度的体系;据此计算的成矿压力范围为24.63～133.61 MPa,成矿深度介于2.46～9.64 km,表明该矿床形成于中深成矿环境。不同成矿阶段流体包裹体研究数据表明,该矿床的成矿作用是一个温度、盐度和压力总体显著降低(减小)、密度略渐增大的过程。氢、氧同位素研究表明,成矿流体在主成矿阶段主要为初始混合岩浆水,随着成矿作用进行,大气降水大量加入,到晚期阶段成矿流体逐渐演化成大气降水。成矿流体在Ⅲ阶段(主成矿阶段)发生了沸腾作用,导致成矿元素沉淀形成矿体。因此认为沸腾作用可能是该矿床金属沉淀的主要机制。  相似文献   

17.
太行山地区的许多金矿产在花岗质岩体内部及其附近的围岩中,产出形式以金属硫化物石英脉为主（如蔡术庵金矿、土石金矿、九集庄金矿等）,部分金矿以爆破角砾岩体的形式出现（如窑沟金矿）,另一部分则以含矿金属硫化物浸染在花岗岩破碎带中的形式产出（如上明峪金矿）...  相似文献   

18.
Li  Songtao  Xia  Yong  Liu  Jianzhong  Xie  Zhuojun  Tan  Qinping  Zhao  Yimeng  Meng  Minghua  Tan  Lijin  Nie  Rong  Wang  Zepeng  Zhou  Guanghong  Guo  Haiyan 《中国地球化学学报》2019,38(4):587-609

The newly discovered Baogudi gold district is located in the southwestern Guizhou Province, China, where there are numerous Carlin-type gold deposits. To better understand the geological and geochemical characteristics of the Baogudi gold district, we carried out petrographic observations, elemental analyses, and fluid inclusion and isotopic composition studies. We also compared the results with those of typical Carlin-type gold deposits in southwestern Guizhou. Three mineralization stages, namely, the sedimentation diagenesis, hydrothermal (main-ore and late-ore substages), and supergene stages, were identified based on field and petrographic observations. The main-ore and late-ore stages correspond to Au and Sb mineralization, respectively, which are similar to typical Carlin-type mineralization. The mass transfer associated with alteration and mineralization shows that a significant amount of Au, As, Sb, Hg, Tl, Mo, and S were added to mineralized rocks during the main-ore stage. Remarkably, arsenic, Sb, and S were added to the mineralized rocks during the late-ore stage. Element migration indicates that the sulfidation process was responsible for ore formation. Four types of fluid inclusions were identified in ore-related quartz and fluorite. The main-ore stage fluids are characterized by an H2O–NaCl–CO2–CH4 ± N2 system, with medium to low temperatures (180–260 °C) and low salinity (0–9.08% NaCl equivalent). The late-ore stage fluids featured H2O–NaCl ± CO2 ± CH4, with low temperature (120–200 °C) and low salinity (0–7.48% NaCl equivalent). The temperature, salinity, and CO2 and CH4 concentrations of ore-forming fluids decreased from the main-ore stage to the late-ore stage. The calculated δ13C, δD, and δ18O values of the ore-forming fluids range from − 14.3 to − 7.0‰, −76 to −55.7‰, and 4.5–15.0‰, respectively. Late-ore-stage stibnite had δ34S values ranging from − 0.6 to 1.9‰. These stable isotopic compositions indicate that the ore-forming fluids originated mainly from deep magmatic hydrothermal fluids, with minor contributions from strata. Collectively, the Baogudi metallogenic district has geological and geochemical characteristics that are typical of Carlin-type gold deposits in southwest Guizhou. It is likely that the Baogudi gold district, together with other Carlin-type gold deposits in southwestern Guizhou, was formed in response to a single widespread metallogenic event.

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19.
甘孜丘洛成矿带金矿的流体包裹体研究   总被引：2，自引：0，他引：2  
王小春 《矿物岩石》1992,12(1):73-79
本文研究金矿石矿物中流体包裹体的特征,成矿流体的性质(成分、盐度和密度)以及矿石形成时的温度和压力,结合金矿化的元素和矿物组合,确定本区金矿化的垂直分带规律。  相似文献   

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