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1.
Based on our study of the nature and variation of mineralization-controlling faults in their deep extension and the spatial distribution of gold orebodies in the northwestern Shandong Peninsula (NSP), here we propose that the gold deposits in the Jiaojia gold belt are controlled by listric faults and the gold deposits in the NSP are controlled by extensional fault system. We also suggest that there is a multiple mineralization space in the deep part of the NSP gold belt. As steps or benches occur along the deep extention of the listric fault where its dipping angle changes from steep to gentle, a number of gold deposits are correspondingly distributed as a steplike pattern, which is named as a step metallogenetic model for gold deposits in the NSP. The gold deposits in Shandong Peninsula were formed in the Cretaceous when the crust in the region experienced extention and thinning following the strong collision between North China Plate and Yangtze Plate during the Triassic. Crust anataxis, fluid remobilization, and extention-detachement of the crust are the leading factors for the gold mineralization.  相似文献   

2.
The North China Craton(NCC) hosts numerous gold deposits and is known as the most gold-productive region of China. The gold deposits were mostly formed within a few million years in the Early Cretaceous(130–120 Ma), coeval with widespread occurrences of bimodal magmatism, rift basins and metamorphic core complexes that marked the peak of lithospheric thinning and destruction of the NCC. Stable isotope data and geological evidence indicate that ore-forming fluids and other components were largely exsolved from cooling magma and/or derived from mantle degassing during the period of lithospheric extension. Gold mineralization in the NCC contrasts strikingly with that of other cratons where gold ore-forming fluids were sourced mostly from metamorphic devolatization in compressional or transpressional regimes. In this paper, we present a summary and discussion on time-space distribution and ore genesis of gold deposits in the NCC in the context of the timing, spatial variation, and decratonic processes. Compared with orogenic gold deposits in other cratonic blocks, the Early Cretaceous gold deposits in the NCC are quite distinct in that they were deposited from magma-derived fluids under extensional settings and associated closely with destruction of cratonic lithosphere. We argue that Early Cretaceous gold deposits in the NCC cannot be classified as orogenic gold deposits as previously suggested, rather, they are a new type of gold deposits, termed as "decratonic gold deposits" in this study. The westward subduction of the paleo-West Pacific plate(the Izanagi plate) beneath the eastern China continent gave rise to an optimal tectonic setting for large-scale gold mineralization in the Early Cretaceous. Dehydration of the subducted and stagnant slab in the mantle transition zone led to continuous hydration and considerable metasomatism of the mantle wedge beneath the NCC. As a consequence, the refractory mantle became oxidized and highly enriched in large ion lithophile elements and chalcophile elements(e.g., Cu, Au, Ag and Te). Partial melting of such a mantle would have produced voluminous hydrous, Au- and S-bearing basaltic magma, which, together with crust-derived melts induced by underplating of basaltic magma, served as an important source for ore-forming fluids. It is suggested that the Eocene Carlin-type gold deposits in Nevada, occurring geologically in the deformed western margin of the North America Craton, are comparable with the Early Cretaceous gold deposits of the NCC because they share similar tectonic settings and auriferous fluids. The NCC gold deposits are characterized by gold-bearing quartz veins in the Archean amphibolite facies rocks, whereas the Nevada gold deposits are featured by fine-grained sulfide dissemination in Paleozoic marine sedimentary rocks. Their main differences in gold mineralization are the different host rocks, ore-controlling structures, and ore-forming depth. The similar tectonic setting and ore-forming fluid source, however, indicate that the Carlin-type gold deposits in Nevada are actually analogous to decratonic gold deposits in the NCC. Gold deposits in both the NCC and Nevada were formed in a relatively short time interval(10 Myr) and become progressively younger toward the subduction zone. Younging of gold mineralization toward subduction zone might have been attributed to retreat of subduction zone and rollback of subducted slab. According to the ages of gold deposits on inland and marginal zones, the retreat rates of the Izanagi plate in the western Pacific in the Early Cretaceous and the Farallon plate of the eastern Pacific in the Eocene are estimated at 8.8 cm/yr and 3.3 cm/yr, respectively.  相似文献   

3.
As one of the important deposit-clustered regionsof China, the Liaodong (eastern Liaoning Province)rift zone contains many large lead, zinc, gold, boron,magnesite and talc ore deposits with a long mininghistory. Recently, large-scale Xiaotongjiapuzi gold andGaojiapuzi silver deposits were discovered in the re-gion. Much work on the origin of these deposits hasbeen carried out, however, the discrepancy on the ageand the metal source of the deposits still rem- discu…  相似文献   

4.
Mercury pollution resulting from artisanal gold mining is a serious environmental problem in many developing countries. In this study, we analyzed heavy metal(loid) contamination in mine wastes from a Carlin-type gold mine in southwestern Guizhou, China. Highly elevated levels of As, Hg, Tl, Sb, and Cd—up to 5844, 28,29, 581 and 3.0 mg/kg, respectively—were observed in the mine wastes, but no significant accumulation of Cr, Ni, Cu,Zn, and Pb was found. The smelting process of gold ores had significant impacts on the enrichment of As, Tl, and Hg in the mine wastes. Due to the significant metal(loid)pollution in this gold mine, the ecological risks are classified as ‘‘very high.' Hg and As are the major pollutants with a relative contribution of 55.9 % and 24.2 % to the risk index, respectively. Phytoremediation could be used to reduce heavy metal contamination and recycle the gold simultaneously. Hg–As–Tl pollution should be considered in gold extraction at Carlin-type gold mines.  相似文献   

5.
The gold contents of 59 samples of mantle-derived xenoliths, along with 85 samples of sulfide assem-blages in them, of Cenozoic basalt from eight districts in eastern China are analyzed. The gold contents of mantle xenoliths usually fall in the range of 10-9―10-8, whereas those of the sulfide assemblages fall in the range of 10-4―10-2. This implies that the latter are several hundred thousand times higher than the former, and thus that Au in the mantle is concentrated mostly in sulfide assemblages. Gold con-tents of both mantle-derived xenoliths and sulfide assemblages in them are inhomogeneous spatially, but their distribution rules are similar. Except the samples from Hainan Province, either the mantle xenoliths with high gold content or sulfide assemblages of the mantle-derived xenoliths with high gold content are distributed mostly on the north and south margins of the North China platform (Hannuoba of Hebei Province and Linqu, Changle of Shandong Province), corresponding to districts with concen-trated gold deposits in northwest Hebei Province and Jiaodong Peninsula of Shandong Province. This may reflect the correlativity in age, nature and composition between the continental crust and the un-derlying lithospheric mantle. The underlying lithospheric mantle of the North China platform is an an-cient gold-rich lithospheric mantle. The gold-rich lithospheric mantle may be the material source of later activation, enrichment, transportation and mineralization of gold by auriferous CO2 mantle fluids.  相似文献   

6.
The North China district has been subjected to significant research with regard to the ore-forming dynamics,processes, and quantitative forecasting of gold deposits; it accounts for the highest number of gold reserves and annual products in China. Based on the top-level design of geoscience theory and the method adopted by the National Key R D Project(deep process and metallogenic mechanism of North China Craton(NCC) metallogenic system), this paper systematically collects and constructs the geoscience data(district, camp, and deposit scales) in four key gold districts of North China(Jiaojia-Sanshandao,Southern Zhaoping, Wulong, and Qingchengzi). The settings associated with the geological dynamics of gold deposits were quantitatively and synthetically analyzed, namely: NCC destruction, metallogenic events, genetic models, and exploration models. Three-dimensional(3D) and four-dimensional(4D) geological modeling was performed using the big data on the districts, while the district-scale 3D exploration criteria were integrated to construct a quantitative exploration model. Among them, FLAC3D modelling and the Geo Cube software(version 3.0) were used to implement the numerical simulation of the 3D geological models and the constraints of the fluid saturation parameters of the Jiaojia fault to reconstruct the 4D fault structure models of the Jiaojia fault(with a depth of 5000 m). Using Geo Cube3.0, multiple integration modules(general weights of evidence(Wof E), Boost Wof E, Fuzzy Wof E, Logistic Regression, Information Entropy, and Random Forest) and exploration criteria were integrated, while the C-V fractal classification of A, B and C targets in four districts was carried out. The research results are summarized in the following four areas:(1) Four gold districts in the study area have more than three targets(the depth is 3000 m), and the class A, B and C targets exhibit a good spatial correlation with gold bodies that are controlled by mining engineering at depths greater than 1000 m.(2) The Boost Wof E method was used to identify the target optimization in 3D spaces(at depths of 3000–5000 m) of the Jiaojia-Sanshandao, Southern Zhaoping, and Wulong districts.(3) The general Wof E method is based on the Bayesian theory in 3D space and provides robust integration and target optimization that are suitable for the Jiaojia-Sanshandao and Southern Zhaoping districts in the Jiaodong area; it can also be applied to the Wulong district in the Liaodong area using a quantitative genetic model and an exploration model. Random forest is a multi-objective integration and target optimization method for 3D spaces, and it is suitable for the complex exploration model in the Qingchengzi district of the Liaodong area. The genetic model and exploration criteria associated with the exploration model of the Qingchengzi district were constrained by the common characteristics of the gold fault structure, magmatic rock emplacement in North China, and the strata fold and interlayer detachment structure.(4) Based on the gold reserves and the 3D block unit model of the Sanshandao gold deposit in the Jiaojia-Sanshandao district, the gold contents of the 3D block units in class A and B targets of the ore concentration were estimated to be 65.5% and 25.1%, respectively. The total Au resources of the optimized targets below a depth of 3000 m were 3908 t(including 1700 t reserves), and the total Au resources of the targets at depths from 3000 to 5000 m were 936 t. The study shows that the deep gold deposits in the four gold districts of North China exhibit a strong "transport-deposition" spatial correlation with potential targets. These "transport-deposition" spatial models represent the tectonic-magmatic-hydrothermal activities of the metallogenic system associated with the NCC destruction events and indicate the Au enrichment zones.  相似文献   

7.
While engineered nanoparticles are widely used and maybe eventually released into the environment,natural nanoparticles are also commonly found in the Earth system.Nanoparticles may critically affect the geochemical migration of associated elements and pose potential threats to the ecological environment.It is necessary to establish an accurate and reliable method for measuring the concentration of nanoparticles.AAS is one of the most commonly used methods for the concentration determination of nanoparticles.However,till now,there has been no systematic report on how experimental variables affect AAS measurements.In this study,we used gold nanoparticles(AuNPs) as an example and studied the influences of a list of factors on the concentration determination of AuNPs by AAS,including digestion method,ionization interference,acidic medium,background correction method,and organic matter.We demonstrate that all these factors may have varying degrees of influence on the measured gold concentrations.When the gold colloid is digested at room temperature for more than 8 h or at 60℃ for more than 2 h,and the system contains a low concentration of organic matter,AAS can accurately measure the AuNP concentration at ppm-level.The deuterium lamp background deduction method is not recommended to use for samples with lower gold concentrations.  相似文献   

8.
<正>North China Craton(NCC)is the most important gold occurrence region in China,and also one of the most important gold districts in the world(Wei et al.,1994;Zhou et al.,2002;Goldfarb et al.,2014).Gold deposits in the region are mostly distributed in the margins of the NCC.Main gold concentration districts include Jiaodong in the eastern margin,  相似文献   

9.
The Kuoerzhenkuola gold field (including the Kuo- erzhenkuola and the Buerkesidai gold deposits), lo- cated 68 km east of Jimunai County in northern Xing- jiang, China, is an important component of the Sawuer gold belt which is the eastward extending part of the Zarma-Sawur gold-copper belt in Kazakhstan. Some studies are concerned with the geology of the gold ores[1―3], the associated volcanic rocks[4], radiogenic isotope[5―8], and the ore-forming environment[8]. Most researchers inferr…  相似文献   

10.
This paper reports the variation rules for the typomorphic parameters of the pyrite and the gold enrichment rules of the Denggezhuang quartz vein gold deposit at a large-depth scale,providing the mineral signs for deep prospecting prediction through detailed study of the characteristics of crystal' habits,chemical composition,the thermoelectricity of pyrites,and mineralogical mapping.This paper primarily discusses the correlation between the mineralization intensity and the space-time evolution of the mineralogical parameters,clarifies the physicochemical conditions during gold mineralization,and provides information useful for deep mineralization prediction.We demonstrate that the crystal habits of the pyrites are very complex,primarily occurring as {100},{210},and their combinate form.{210} and {100}+{210} have positive correlations with gold mineralization,and {100}+{210} therefore can be useful for locating rich ore segments.The composition of pyrites is characteristically poor in S and rich in As.Their typical trace elements are composed of Mo,As,Pb,Cu,Bi,Zn,Au,Co,Se,Sb,Ag,Ni,Cr,and Te.The average contents of trace elements in pyrites from various stages show that the crystallizing temperature gradually decreased from an early stage to the metallogenic episodes.The precipitation and accumulation of Au and Ag occur primarily in the quartz-pyrite stage(III) and the polymetal minerals stage(IV).The occurrence rate of P-type pyrites(P(%)) is 83.52%.There is a larger dispersion of the thermoelectrical coefficient of pyrite(α) in the Denggezhuang gold deposit than in other deposits in the Jiaodong Peninsula.The electrical conductivity assemblage of pyrites from I to V is characterized by P≥N→PN→PN→PN→P≥N,which is usually considered beneficial for mineralization.The relative contents of As+Sb+Se+Te and Co+Ni are closely correlated to P-type and N-type average values and their occurrence rates.According to the crystallizing temperature of pyrite,the mineralization intensity,and the denudation degree,the mineralization temperature of the Denggezhuang gold deposit is in the range of 150–322℃ and is of a medium-low temperature.The orebody has already become denuded to the top-middle of the orebody,and the size of the orebody is larger than 900 m.Based on the vertical zoning of the thermoelectrical coefficients of pyrites and P-type pyrite mapping,it is suggested that the segment between ?425 and ?800 m may have exploration potential to the northeast of line 94 of the No.I2-2 orebody.  相似文献   

11.
The theory and equations of the residual apparent polarization method are proposed and described in this article. Based on studies of existing mines, the residual apparent polarization ηα^sy, calculated from the induced-current middle-gradient apparent polarizations ηα^sy at large and small electrode spaces over the known deep Jiaojia-type gold mines, have been shown to separate the effects of mines from the anomalous polarizations generated from the strongly altered rocks in fracture zones.  相似文献   

12.
The Yueguang gold deposit is located in Fengjia, Xinhua County, Hunan Province, South China. It represents a recently discovered small-scale gold deposit situated in the southwestern region of the Jiangnan Orogenic Belt, west of the Baimashan granitic batholith. In order to discern the characteristics of the ore-forming fluids, the underlying mineralization processes, and establish a foundation for the origin of the Yueguang gold deposit fluid inclusion micro-thermometry, as well as quartz hydro...  相似文献   

13.
Suites of granitic and metamorphic rocks form a perfect geological environment in which to investigate the source of metals related to gold deposits. In the East Province of Cameroon, the source of metals-related gold(grade ～ 4.6 g/t) that occurs within metamorphic and granitic rocks remains ambiguous. The host rocks were subjected to XRF and ICP-MS whole-rock geochemistry and BSE/EDS mineral analyses to investigate the source(s) of metals related to gold in the Province. Petrographically, chalc...  相似文献   

14.
The Anjiayingzi gold deposit in Chifeng County, Inner Mongolia is located in the central part of the gold mineralization belt of the northern margin of the North China Craton (NCC), and is adjacent to the Paleozoic Inner Mongolia-Da Hinggan Mountains orogenic belt in the north. The Chifeng-Kaiyuan fault, which separates the NCC from this orogenic belt, is considered to be a regional ore-controlling structure. The Anjiayingzi gold deposit is a mediate-size quartz lode-gold deposit and is hosted by the Anjiayingzi quartz monzonite that was emplaced into the basement composed of early Precambrian gneisses. Rhyolitic and porphyritic dikes are generally associated with the gold mineralization. Zircon U-Pb analyses suggest that the Anjiayingzi granite was emplaced from 132 Ma to 138 Ma, while the rhyolitic dikes that occupy the same fracture system as the gold-bearing quartz veins and locally crosscut the gold lodes crystallized from 125 Ma to 127 Ma. These results constrain the mineralization age between 126  相似文献   

15.
The Sandaowanzi gold deposit is an extremely Au-rich deposit in the Northern Great Hinggan Range in recent years.Zircon U-Pb geochronology,Hf isotope analysis,and the geochemistry of andesites of the Longjiang Formation from the Sandaowanzi gold deposit were used to investigate the origin,magmatic evolution as well as mineralization and tectonic setting of the Early Cretaceous epithermal gold deposits in the northern Great Hinggan Range area.Zircon U-Pb dating reveals an emplacement age of 123.4±0.3 Ma,indicating that the andesites of the Sandaowanzi gold deposit was formed during the Early Cretaceous.The andesites are enriched in light rare earth elements relative to heavy rare earth elements and have weak negative Eu anomalies(δEu=0.76-0.90).The rocks are also enriched in large-ion lithophile elements,such as Rb,Ba,Th,U,and K,and depleted in the high-field-strength elements,such as Nb,Ta,and P.These characteristics are typical of volcanic rocks related to subduction.Igneous zircons from the andesite samples have relatively homogeneous Hf isotope ratios,~(176)Hf/~(177)Hf values of 0.282343-0.282502,εHf(t) values of-12.58 to-6.95,and two-stage model ages(T_(DM2)) of 1743-1431 Ma.The characteristics of the andesites of the Longjiang Formation are consistent with derivation from partial melting of enriched mantle wedge metasomatized by subducted-slab-derived fluids.These rocks formed in an extensional environment associated with the closure of the Mongol-Okhotsk Ocean and subduction of the Paleo-Pacific Plate.Mineralization occurred towards the end of volcanism,and the magmatic activity and mineralization are products of the same geodynamic setting.  相似文献   

16.
The Shandong Peninsula (Jiaodong) is a very important gold producer of China. Over ten large and super-large quartz-vein type and shear zone-type gold deposits related to Yanshannian granite intrusions have been exploited in the northern part of the Jiaod…  相似文献   

17.
Jiaojia-pattern gold mines could be surveyed by utilizing large-power induced polarization sounding. Firstly, a multi-layered numerical model of a polarization body was established in sense of physical and mathematical derivation. The polarization field generated from the model was the stack of individual fields generated from multi-layered polarization units. The equation for eliminating strong shallow polarization anomalies from the sounding data was derived based on the principle of multiply eliminating the fields of individual polarization units. As a result, the deep polarization anomalies were prominent. The processed sounding data was used to quantitatively calculate the depths to the tops of deep altered zones of golden mineralization.  相似文献   

18.
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±N2system,with medium to low temperatures(180–260℃)and low salinity(0–9.08%NaCl equivalent).The late-ore stage fluids featured H2O–NaCl±CO2±CH4,with low temperature(120–200℃)and low salinity(0–7.48%Na Cl equivalent).The temperature,salinity,and CO2and CH4concentrations of ore-forming fluids decreased from the main-ore stage to the late-ore stage.The calculated δ^13C,d D,and δ^18O 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 δ^34S 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.  相似文献   

19.
Single zircon LA-ICP-MS U-Pb dating and lithogeochemical studies have been performed on the Xianggou monzonitic granitic porphyry outcropped in the Ma'anqiao gold deposit.A weighted average U-Pb age of 242.0±0.8 Ma for Xianggou monzonitic porphyry has been obtained.This corresponds with the conclusions of previous studies indicating a syn-orogenic age (242±21 Ma) of the Qinling Orogenic Belt,suggesting that the formation of the Xianggou granite should be associated with the collisional event of the North China Plate and the Yangtze Plate in the Indosinian period.The Xianggou granite is characterized by the high silicon and alkali of high K calc-alkaline series granites.It is rich in Al (Al2O3=14.49%-15.61%) and Sr (457.10-630.82 ppm),poor in Y (16 ppm) and HREE (Yb0.45 ppm),and exhibits high ratios of Sr/Y (76.24-97.34) and (La/Yb)N (29.65-46.10),as well as strongly fractionated REE patterns.These geochemical characteristics suggest the Xianggou granite can be classified as C-type adakitic rock.The initial Sr isotope ratios for the Xianggou granite vary from 0.70642 to 0.70668,εNd(t) values from -4.54 to -3.98,and TDM values from 1152 Ma to 1220 Ma.The low εNd(t) and ISr and high TDM values,as well as Na2O/K2O ratios of the Xianggou granite are close to 1 (Na2O/K2O=0.95-1.10),indicating that it is not an I-type adakite formed by partial melting of the subducting oceanic crust,nor adakitic rock formed by melting of the underplated basaltic lower crust,but the product of partial melting of the nonunderplated basaltic thickened lower crust.Zircons from the Xianggou pluton have a homogeneous Hf isotopic composition with negative εHf(t) values (between -9.7 and -5.9,with an average of -6.9),indicating that the rock-forming materials were mostly extracted from the ancient crust,not from the depleted mantle.The Xianggou monzonitic granitic porphyry is rich in LILE and LREE and depleted in HSFE,HREE and Y;the composition of trace element and REE are similar to those of the syn-collisional granites.The geological and geochemical characteristics of the Xianggou granite reveal that it was a product of partial melting of the basaltic rocks from the thickened lower crust,triggered by continental collision,which occurred in the geodynamic background of continental-continental collision and shearing within the crust.The Xianggou granite was intruded in the compressive orogenic environment 242 Ma ago,but the gold mineralization occurred in the transitional environment of compression to extension around 170 Ma ago,lagging behind the intrusive age of the Xianggou granite by about 70 Ma.Meanwhile,the distribution of trace elements and REEs of the Xianggou monzonitic granitic porphyry is distinct from that of ores,suggesting the absence of direct genetic relationship between the Xianggou granite and gold mineralization.In contrast,the relatively high ore-forming elemental content of the Xianggou monzonitic granitic porphyry is due to the rock having experienced Au-bearing hydrothermal alteration.From the view of gold mineralization,considering the intrusive age,structural deformation,as well as alteration of the granite,we can conclude that the Xianggou pluton was a pre-ore-intrusion,whose intrusive age of 242 Ma constrains the lower time limit of gold metallogenesis.Following the intrusive event of the syn-collisional granitic porphyry and the intensively brittle-ductile shear deformation,large-scale fluid activity and gold mineralization took place.  相似文献   

20.
The fault-controlled Nibao Carlin-type gold deposit,together with the strata-bound Shuiyindong deposit,comprise a significant amount of the disseminated gold deposits in southwestern Guizhou Province,China.Five main types and two sub-types of pyrite at the Nibao deposit(Py1a/Py1b,Py2,Py3,Py4,Py5)were distinguished based on detailed mineralogical work.Py1,Py2and Py3 are Au-poor,whereas Py4 and Py5 are Au-rich,corresponding to a sedimentary and hydrothermal origin,respectively.Through systematic in situ analyses of NanoSIMS sulfur isotopes,the framboid pyrite Py1a with negative δ^34S values(-53.3 to-14.9%)from the Nibao deposit were found to originate from bacterial sulfate reduction(BSR)processes in an open and sulfate-sufficient condition while the superheavy pyrite Py1b(73.7–114.8%)is probably due to the potential influence of closed-system Rayleigh fractionation or the lack of preservation of deepsea sediments.Data of Py2 and Py3 plot within the area of S isotope compositions from biogenic and abiogenic sulfate reduction.In view of few coeval magmatic rocks in the mining district,the near zero δ^34S values of the Au-rich pyrites(Py4 and Py5)may discount the potential involvement of magmatic but metamorphic or sedimentary origin.LA-ICP-MS and TEM work show that Au in ore-related pyrite is present as both nanoparticles and structurally bound.LA-ICP-MS analyses show that the Au-rich pyrite also contains higher As,Cu,Sb,Tl and S than other types of pyrite,which inferred a distal manifestation of deep hydrothermal mineralization systems.  相似文献   

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