Sources and fluid regime of quartz-carbonate veins at the Sukhoi Log gold deposit,Baikal-Patom Highland

Complex (δ¹⁸O, δ¹³C, ⁸⁷Sr/⁸⁶Sr, ¹⁴³Nd/¹⁴⁴Nd, and REE composition) data were obtained on quartz-carbonate veins in metasedimentary rocks to elucidate the material sources and to evaluate fluid regime during low-sulfide gold-quartz ore mineralization at the Sukhoi Log deposit. In order to use an oxygen isotopic thermometry for quartz veins, we calibrated empirical dependence of fractionation factors between vein quartz and altered wall rocks. The temperature range of quartz equilibration with wall rocks was evaluated at 380–190°C. Independent temperatures obtained using this thermometer indicate that the vein ankerite can be both earlier and later than vein quartz. The isotopic systematics (δ¹³C and δ¹⁸O) of ankerite in the quartz-carbonate veins, carbonates in the ore-hosting shales of the Khomolkho and Imnyakh formations both within and outside mineralized zones at the deposit indicate that the ore-hosting rocks and veins in the mineralized zone contain incoming carbonate, which was most probably borrowed from the carbonate rocks of the Imnyakh Formation. REE composition of vein ankerite shows that these elements were transported by fluid as carbonate complexes. The behavior of the Eu/Eu* and (La/Yb)_n ratios and Mn of the vein ankerite suggest that during carbonate crystallization the system was closed with respect to fluid. Sr-Nd isotope systematics indicates that the isotopic parameters of the vein ankerite were formed with the participation of metasedimentary host rocks of both the Imnyakh and Khomolkho formations, which are contrastingly different in Nd isotopic composition. A fluid/rock ratio during metasomatic processes in the wall rocks was calculated for two scenarios of their thermal history: with a continuously operating heat source beneath the Sukhoi Log structure and with a linear cooling of the structure. The effective integral W/R ratios calculated lie within the range of 0.046–0.226 and suggest that the veins were produced with the metamorphic fluid. Low W/R ratios are inconsistent with the mechanism of vein quartz crystallization due to fluid oversaturation with respect to SiO₂ at decreasing temperature. We believe that the main mechanism responsible for the origin of these veins was variations of fluid oversaturation due to pressure variations (pressure solution mechanism). This hypothesis is consistent with the reported isotopic-geochemical characteristics of the wall rocks at the Sukhoi Log deposit.     

Age and pyrite Pb-isotopic composition of the giant Sukhoi Log sediment-hosted gold deposit, Russia

Sukhoi Log is one of the largest gold deposits in Russia (1100 t Au at 2.45 g/t). Like many other sediment-hosted gold deposits throughout the world, Sukhoi Log preserves textural, structural and geochemical evidence for multiple generations of Au enrichment and pyrite growth.The deposit is located in the Lena gold province of Siberia, on the edge of the Siberian Craton and occurs in the core of a recumbent anticline in a Neoproterozoic black shale and quartz-rich siltstone-sandstone turbidite succession. Temporal constraints on pyrite paragenesis at the deposit have been determined using laser ablation inductively coupled mass spectrometry (LA-ICPMS) measurements of U, Th and Pb isotopes in pyrite, monazite and zircon. LA-ICPMS age determinations on detrital zircons indicate the host rocks were deposited after 600 ± 10 Ma and derived from a mixture of Palaeoproterozoic and Neoproterozoic sources. The U, Th and Pb isotopic systematics indicate the cores of large monazite crystals, which predate obvious tectonic fabric development in the host rocks, began growing at 573 ± 12 Ma. The rims of the same monazite crystals formed at 516 ± 10 Ma, during peak metamorphism and deformation. Small monazite crystals also grew in the sedimentary rocks during the Devonian (374 ± 20 Ma) and the Carboniferous or Early Permian (288 ± 22 Ma), possibly in response to fluid movements triggered by synchronous granite intrusion in the area. Multi-collector and quadrupole LA-ICPMS Pb isotopic determination on pyrite, combined with overprinting criteria, show that the earliest (stratiform) Pb and Au-bearing pyrite formed prior to metamorphism—possibly during sedimentation or early diagenesis (575-600 Ma). Small Au-rich pyrite nodules preserved as cores to folded bedding-parallel pyrite-quartz veins probably grew during late diagenesis or early metamorphism. Large pyrite euhedra, which overgrow the strong axial planar cleavage in the host rocks, have more radiogenic Pb-isotopic compositions and formed either late during or after deformation. Framboidal pyrite that is overgrown by both the late diagenetic-early metamorphic and syn- to post-metamorphic pyrite has the most radiogenic Pb-isotopic composition suggesting exchange with radiogenic Pb in the matrix may have continued until late in the history of the deposit.The dating and Pb isotopes support a multistage origin for the gold deposit with Au first introduced during or prior to growth of the earliest stratiform pyrite and progressively re-concentrated (with or without addition of further gold) during later metamorphic events.     

Noble metals in black shales of the Sukhoi Log gold deposit (East Siberia): evidence from scintillation arc atomic-emission spectrometry

Scintillation arc atomic-emission spectrometry (SAES) is used to study noble metals (NM), including Au, Ag, Pt, Pd, Ir, Os, Rh, and Ru, in black shales of the Sukhoi Log gold deposit (Irkutsk Region, Russia), with a focus on NM total contents in samples and on the compositions and sizes of NM-bearing particles. The estimated sizes of gold particles and their distribution are confirmed by results of scanning electron microscopy combined with energy dispersive X-ray microanalysis (SEM-EDX). The SAES results are in satisfactory agreement with earlier SEM-EDX data on NM species but reveal a much greater number and diversity of element associations.     

Oxygen isotopic composition of quartz veins and host rocks at the Sukhoi Log deposit,Russia

The relationships between the δ¹⁸O of quartz veins and veinlets pertaining to the main stage of gold mineralization at the Sukhoi Log deposit and metasomatically altered host slates are estimated. The oxygen isotopic composition of veined quartz and host slates is not uniform. The δ¹⁸O of quartz veins from the Western, Central, and Sukhoi Log areas of the deposit vary from +16 to + 18 ‰. The δ¹⁸O range of metasomatically altered slates in the Western and Sukhoi Log areas attains 6 ‰. The δ¹⁸O of quartz veins are always higher than those of host slates by 3–7‰. The regular difference in the δ¹⁸O between quartz veins and host slates indicates that the oxygen isotopic composition of the ore-bearing fluid forming the system of quartz veins and veinlets at the Sukhoi Log deposit could have formed as a result of interaction with silicate rocks, for instance, terrigenous slates enriched in δ¹⁸O. Such interaction, however, took place at deeper levels of the Sukhoi Log deposit. It is suggested that the fluid phase participating in the formation of the vein and veinlet system had initially high δ¹⁸O(>+10‰) due to interaction with the rocks enriched in δ¹⁸O at a low fluid/rock ratio. The oxygen isotope data indicate that the fluid participating in the formation of gold mineralization at the Sukhoi Log deposit was not in equilibrium with igneous rocks at high temperatures.     

Typomorphism of pyrite of the Sukhoi Log deposit (East Siberia)

The typomorphic features of pyrite of the Sukhoi Log deposit were studied by a set of volumetric and surface methods: electron probe microanalysis, scanning electron and probe microscopy, powder X-ray diffraction, X-ray photoelectron and Auger electron spectroscopy, atomic-absorption spectrometry in the SSADSC (method of statistical sample of analytical data for single crystals) version, and atomic-emission spectrometry. Pyrite from the Sukhoi Log deposit has the following distinctive features: permanent presence of sulfite ion, which often dominates over other surface sulfur anions; weakly determined size dependence of the content of uniformly distributed Au owing to the presence of an internal concentrator of gold—dispersed carbonaceous material—in pyrite from ore zones; cell sculptures of the crystal faces, which appeared owing to the nanofragmentation of the growth surface; micro- and nanoinclusions of carbonaceous phases within crystals, associated with defects in their structure; and thin films enriched in O and C on the surface of and within the crystals. It has been shown that gold-sulfide mineralization at the Sukhoi Log deposit formed in a single ore-generating hydrothermal system, in which gold, sulfur, and carbon belonged to a microparagenesis. Some features (composition of surface, characteristics of submicroscopic structure, and elemental composition) evidence that the conditions of crystallization of pyrite in inter-ore space were different from the conditions of its genesis in the ore zones, which suggests the presence of at least two genetic types of pyrite. Carbonaceous micro- and nanoparticles and O- and C-containing films can favor an increase in the adsorption of gold from cyanide solutions on pyrite. To reduce this effect during gold recovery, a technique for surface modification should be elaborated. The ways for solving the most complicated problems dealt with the source of noble metals (NM) and the ore specialization of the deposit have been outlined. For this purpose, a detailed analysis of the main ore minerals for trace-element speciation is required. In the case of the magmatic source of NM, correlation between the contents of Au and PGE structural forms should exist. On the other hand, there is no correlation between the structural forms of Au or Pt and elements whose contents in fluid are determined by the host rock rather than the magmatic source.     

Heterogeneity of the sulfur isotopic composition of pyrite at the Sukhoi Log deposit and its controlling factors

Doklady Earth Sciences -     

Relationship between metamorphism and ore formation at the Sukhoi Log gold deposit hosted in black slates from the data of U-Th-Pb isotopic SHRIMP-dating of accessory minerals

The formation conditions and age of the Sukhoi Log gold deposit are considered on the basis of new isotopic-geochemical data. The U-Pb isotopic study of zircon and monazite from high-grade ore and host black slates at the Sukhoi Log deposit was carried out with SIMS technique using a SHRIMP II instrument. Two generations of monazite are distinguished on the basis of optical and scanning electron microscopy, cathodoluminescence, and micro X-ray spectroscopy. Monazite I is characterized by black opaque porphyroblasts with microinclusions of minerals pertaining to metamorphic slates and structural attributes of pre- and synkinematic formation. Monazite II occurs only within the ore zone as transparent crystals practically free of inclusions and as rims around monazite I. The REE contents are widely variable in both generations. Porphyroblastic monazite I differs in low U and Th (0.01–0.7 wt % ThO₂) contents, whereas transparent monazite II contains up to 4 wt % ThO2. The average weighted U-Pb isotopic age of monazite I is 650 ± 8.1 Ma (MSWD = 1.6; n = 9) and marks the time of metamorphism or catagenesis. The U-Pb age estimates of synore monazite II cover the interval of 486 ± 18 to 439 ± 17 Ma. Zircons of several populations from 0.5 to 2.6 Ga in age are contained in the ore. Most detrital zircon grains have porous outer rims composed of zircon and less frequent xenotime with numerous inclusions of minerals derived from slates. The peaks of ²⁰⁶Pb/²³⁸U ages in the most abundant zircon populations fall on 570 and 630 Ma and correspond to the age of newly formed metamorphic mineral phases. The discordant isotopic ages indicate that the U-ThPb isotopic system of ancient detrital zircons was disturbed 470–440 Ma ago in agreement with isotopic age of monazite II and the Rb-Sr whole -rock isochron age of black slates (447 ± 6 Ma). The new data confirm the superimposed character of the gold-quartz-sulfide mineralization at the deposit. Black shales of the Khomolkho Formation of the Bodaibo Synclinorium were affected by metamorphism over a long period; the peaks of metamorphism and catagenesis are dated at 570 and 650–630 Ma. The high-temperature ore formation was probably related to a hidden granitic pluton emplaced 450–440 Ma ago, that is, 200 Ma later than the events of greenschist metamorphism. Hercynian granitoid magmatism (320–270 Ma) did not exert a substantial effect on the U-Th-Pb isotopic system in accessory minerals from the ore and could not have been a major source of ore-forming fluids.     

Fluid chemistry and processes at the Porgera gold deposit, Papua New Guinea

The Porgera gold deposit in Papua New Guinea is a world-class example of an alkalic-type epithermal gold system (stage II), which overprints a precursor stage of magmatic-hydrothermal gold mineralization (stage I). Gas and ion chromatographic analyses of fluid inclusions contained in vein minerals from both mineralization stages have been carried out in order to constrain the compositions of the fluids involved in, and the processes attending, ore deposition. These data indicate the presence of three end-member liquids, the most dilute of which was present throughout the mineralization history and is interpreted to represent evolved groundwater of meteoric origin. Its composition is estimated to have been approximately 500 mM Na⁺, 10 mM K⁺, 5 mM Li⁺, 250 mM Cl⁻, 0.15 mM Br⁻, and 0.01 mM I⁻, plus significant concentrations of dissolved gases. More saline liquids were also present during the two main stages of ore formation, and although their compositions differ, both are interpreted to have been derived at least in part from magmatic fluids, and to have been the media by which gold was introduced into the system. Stage I minerals contain fluid inclusions which decrease in salinity towards this dilute end-member composition through the vein paragenesis, reflecting progressive dilution at depth of the magmatic fluid source by groundwaters. Ore deposition is thought to have been caused largely by simple cooling and/or wallrock reactions, although limited in situ fluid mixing may also have occurred. The most saline fluids, present in early quartz and pyrite, contain at least 810 mM Na⁺, 530 mM Ca²⁺, 130 mM K⁺, 12 mM Li⁺, 87 mM SO₄ ²⁻, 960 mM Cl⁻, 1.1 mM Br⁻, and 0.05 mM I⁻, plus significant but variable concentrations of dissolved gases. Fluid inclusions from stage II hydraulic breccia veins reveal the presence of two distinct liquids with contrasting salinities, which were present at different times during vein formation. A higher salinity liquid appears to have predominated during mineralization, whereas lower salinity groundwaters filled the structures during intervening periods. The ore-forming fluid may have been forcibly injected into the veins from depth during fracturing and depressurization events, displacing the resident groundwaters in the process. The original composition of this fluid is estimated to have been at least 1770 mM Na⁺, 59 mM K⁺, 180 mM Li⁺, 210 mM SO₄ ²⁻, 680 mM Cl⁻, 1.4 mM Br⁻, and 0.09 mM I⁻, plus 1.5 mol% CO₂, 0.19 mol% CH₄, and 0.04 mol% N₂. Gas chromatographic analyses of fluid inclusions from stage II samples show a decrease in total gas content between early unmineralized veins and post-mineralization vuggy quartz (suitable samples could not be obtained from the ore stage itself). Post-mineralization samples plot along an experimental gas-saturation curve in the CO₂-CH₄-H₂O-NaCl system, obtained at conditions similar to those attending stage II ore deposition at Porgera (200–300 bar, ˜165 °C). These results are interpreted to indicate a period of depressurization-induced phase separation during hydraulic fracturing, which resulted in rich ore deposition. Volatile gases such as CH₄ and N₂, in addition to CO₂ in solution, are shown to have a significant negative effect on total gas solubility. This effect may be of critical importance in lowering the temperature and increasing the depth (pressure) at which phase separation can occur in epithermal systems. Received: 28 November 1995 / Accepted: 17 July 1996     

胶东牟平邓格庄金矿床流体包裹体研究

邓格庄金矿是胶东牟平-乳山金成矿带内第二大石英脉型金矿,金主要产于黄铁矿和多金属硫化物石英脉/细脉中。流体包裹体研究表明,邓格庄金矿不同蚀变带岩石和各成矿阶段金矿石中的流体包裹体主要有三种类型：H2O-CO2包裹体、CO2-H2O±CH4包裹体和H2O溶液包裹体。早期乳白色石英中主要赋存原生的H2O-CO2包裹体和次生的CO2-H2O±CH4包裹体;成矿期黄铁矿石英脉和多金属硫化物石英脉中的CO2-H2O±CH4包裹体主要为原生,随机分布,气液比变化较大,有时出现不同相比例的包裹体共存现象,而H2O溶液包裹体明显沿愈合裂隙分布;在成矿晚期的石英和方解石中主要发育原生H2O溶液包裹体。显微测温结果显示,成矿前（第1阶段）H2O-CO2包裹体的完全均一温度（Th,TOT,至液相）为254℃至365℃,成矿期（第Ⅱ和Ⅲ阶段）CO2-H2O±CH4包裹体的完全均一温度（Th,TOT,至液相）为195～317℃,成矿后（第Ⅳ阶段）H2O溶液包裹体的均一温度（Th,TOT;至液相）为156—219℃。成矿的初始流体富CO2,主成矿期有CH4流体加入,成矿晚期则演化为低温的水溶液流体。水／岩反应及流体不混溶可能是邓格庄金矿金沉淀的主要原因。     

Fluid evolution in a slate-belt gold deposit

Auriferous quartz veins in the Hill End goldfield, NSW, Australia, comprise bedding-parallel vein sets and minor extension and fault-controlled veins which are hosted by a multiply deformed, Late Silurian slate-metagreywacke turbidite sequence. Fluid inclusions in quartz, either from bedding-parallel veins or from narrow, steeply N-dipping veins (‘leader’ veins) indicate a similar range in homogenisation temperatures (T_h) from 350°C to 110°C. Within this range, T_h data demonstrate five groupings in the temperature intervals 350–280°C, 280–250°C, 250–190°C, 190–150°C, and 150–110°C, corresponding to a variety of primary and secondary inclusions developed during five periods of vein growth under a generally declining temperature regime. Inclusion fluids are characterised by a low salinity of around 0.1 to 3.6 wt% NaCl equivalent. Laser Raman microprobe inclusion analysis indicates that gas-phase compositions relate to the paragenetic stage of the host quartz. H₂O_(g) and N₂ dominate in the primary inclusions from barren, Stage I quartz; CH₄ and CH₄ + H₂O_(g) are important in inclusions related to the early gold forming events (equivalent to Stages II and III quartz), but inclusions developed during the last episode of gold deposition are characterised by H₂O_(g), CO₂-rich and liquid-CO₂ bearing fluids. Precipitation of gold was aided by sulphidation reactions or phase separation in response to periods of vein opening. Late in the paragenesis, gold deposition may have been promoted by oxidation of the ore fluid.     

辽宁丹东四道沟金矿床叠生成因的流体包裹体证据

四道沟金矿床为辽东南地区一重要蚀变岩型矿床,其空间产出受构造、盖县组变质地层及区内岩浆活动的联合制约。矿化分3种类型、4个成矿阶段。流体包裹体研究表明,成矿早期流体为一中温、低盐度且富含CO2及CH4等挥发份的热液;矿区主成矿阶段成矿流体为一中温高盐度类型热液。综合分析认为,四道沟金矿床是燕山晚期不同来源及性质的热液先后叠加成矿作用的产物,矿床属叠生成因类型。     

Lead isotopic composition from data of high-precession MC-ICP-MS and sources of matter in the large-scale Sukhoi Log noble metal deposit,Russia

The lead isotopic composition of 33 sulfide samples from orebodies of the Sukhoi Log deposit was studied by high-precession MC-ICP-MS with a precision of ±0.02% (±2SD from 120 analyses of the SRM 981 standard sample). The deposit is located in the Bodaibo gold mining district in the northern Baikal-Patom Highland. Gold mineralization is hosted in Neoproterosoic black slates. Variations of lead isotope ratios of the Sukhoi Log sulfides are generally typical of Phanerozoic deposits and ore fields. They are significant for ²⁰⁶Pb/²⁰⁴Pb (17.903–18.674), moderate for ²⁰⁸Pb/²⁰⁴Pb (37.822–38.457), and relatively narrow for ²⁰⁷Pb/²⁰⁴Pb (15.555–15.679). In the Pb-Pb isotope diagrams, the data points of pyrite and galena constitute a linear trend. The points corresponding to pyrite from metasomatic ore occupy the left lower part of the trend. Galena from late gold-quartz veins shows more radiogenic Pb, and corresponding data points are located in the upper part of the trend. According to the Stacey-Kramers model, the end points of the trend, which is regarded as a mixing line, have μ₂ = 9.6 and μ₂ = 13.2 and model Pb-Pb ages 455 and 130 Ma, respectively. The isotope characteristics of ore lead, their relationships in pyrite and galena, and the mixing trend of Pb isotopic compositions are clearly tied to two Paleozoic stages in the formation of the Sukhoi Log deposit (447 ± 6 and 321 ± 14Ma) and testify to the leading role of crustal sources, which are suggested as being the Neoproterozoic black-shale terrigenous-carbonate rocks.     

新疆马热勒铁金矿床特征及其流体成矿作用

马热勒铁金矿床产于中泥盆统北塔山组安山岩和安山质凝灰岩间的韧性剪切带中.矿体呈脉状,主要为蚀变岩和含金石英脉.矿石由黄铁矿、黄铜矿、方铅矿、黝铜矿、自然金、银金矿、毒砂、辉铋矿、磁铁矿、石英、绢云母、绿泥石、方解石等矿物组成,围岩蚀变有硅化、碳酸盐化、黄铁矿化和绢云母化.金矿成矿主要经历黄铁矿-石英-金、石英-金属硫化物-金、石英-碳酸盐-金三个阶段.成矿物质主要来源于中泥盆统北塔山组含金建造.流体包裹体研究显示,成矿温度为160℃~280℃,成矿压力为(73.4~121.9)×105Pa,成矿时成矿流体pH为4.20~5.01,呈酸性,Eh为-0.66~-0.45eV,属还原环境;流体为Na+-Ca2+-HCO3--Cl-型体系和Na+-Ca2+-HCO3--SO42--Cl-型体系的酸性-弱酸性流体,流体中成矿物质金主要以[AuCl2]-、[Au(HS)2]0等络合物形式存在并运移;流体的溶液来自岩石建造水、古大气降水及变质水组成的混合水.区域构造应力作用、成矿流体环境物理化学条件的改变、古大气水不断加入、成矿流体与围岩的蚀变反应等引起成矿流体周围一系列环境物理化学条件的变化,是马热勒铁金矿床成矿的关键.     

Occurrences of dendritic gold at the McLaughlin Mine hot-spring gold deposit

Two styles of gold dendrites are variably developed at the McLaughlin Mine. The most abundant occurrence is hosted by amber-coloured hydrocarbon-rich opal. Silica likely precipitated from a boiling hydrothermal fluid and complexed with immiscible hydrocarbons forming an amorphous hydrocarbon-silica phase. This phase likely scavenged particulate gold by electrostatic attraction to the hydrocarbon-silica phase. The dendritic nature of the gold is secondary and is the result of dewatering of the amorphous hydrocarbon-silica phase and crystallization of gold into syneresis fractures. The second style of dendritic gold is hosted within vein swarms that focused large volumes of fluid flow. The dendrites occur along with hydrocarbon-rich silica at the upper contact of the vein margins which isolated the dendrites allowing sufficient time for them to grow. In a manner similar to the amber-coloured opal, the dendrites may have formed by scavenging particulate gold by electrostatic attraction to the hydrocarbon-silica phase.     

小秦岭文峪金矿床流体包裹体研究及矿床成因

文峪金矿位于小秦岭矿田南部,其产出受脆-韧性剪切带控制,赋矿围岩为太华群变质杂岩.根据脉体穿切关系和矿物交代关系,可以将文峪金矿流体成矿过程分为早、中、晚三个阶段,其热液石英中发育CO2-H2O型、纯CO2型和H2O溶液型三种类型流体包裹体.平阶段石英中原生包裹体主要是CO2-H2O型和纯CO2型,其成分为CO2+H2O±N2±CH4,均一温度集中在290～330℃,盐度为1.02％～9.59％ NaCleqv;中阶段为主成矿阶段,该阶段石英中包含了所有3种类型的包裹体,其中以CO2-H2O型包裹体为主,获得CO2-H2O和水溶液包裹体均一温度集中在250～290℃,盐度为0.02％～12.81％NaCleqv;晚阶段石英仅发育水溶液型包裹体,具有较低的均一温度(114～239℃)和盐度(4.18％～8.95％ NaCleqv).根据CO2-H2O型包裹体计算早、中阶段压力分别为130 ～ 178MPa和85 ～ 150MPa,对应的成矿深度分别为4.7～6.5km和3.1～5.5km.总体而言,文峪金矿的初始流体具有中高温、富CO2、低盐度的变质流体特征,晚成矿阶段流体演化为低温、低盐度水溶液流体,流体的不混溶导致了主成矿期矿质的大量沉淀,文峪金矿为中浅成的造山型矿床.     

北山金窝子金矿床流体包裹体特征及成矿流体演化

金窝子金矿床为于甘肃北山中成矿带。包裹体测温研究表明,从成矿初期到主成矿阶段,石英捕获了H2O—NaCl,H2O-CO2-CH4-NaCl,或H2O-CO2-NaCl体系的流体。大脉型金矿成矿初期,热液成矿流体由高温中盐度H2O-NaCl-CO2-CH4四端元组份混溶的均一相热液流体;石英-黄铁矿和多金属硫化物阶段,石英捕获两成分和温度都不相同的热液组份：低盐度、富水溶液、较冷的热液和高盐度、富挥发份CO2、CH4和水蒸气、较热的热液。主成矿阶段石英捕获的两类型包裹体的完全均一温度相差近100℃,而且富挥发份流体盐度相对于贫挥发份流体盐度高,上述特征表明主成矿期3号脉大规模金成矿并非流体沸腾作用结果。网脉型金矿（210号脉）黄铁矿-石英成矿阶段、石英．黄铁矿和多金属硫化物成矿阶段石英捕获的地质流体的温度-成分特征无明显差异,均捕获了两种组份不同、成矿温度一 致的地质流体（高盐度富水溶液流体和富堤盐度CO2＋CH4流体）,与许多金矿的流体不混溶金成矿机制矛盾。