1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the...1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the junction of Siberian Block in the south part,North China Block in the north and Songliao block in the east.The Daolundaba copper polymetallic deposit is hosted by the Lower Proterozoic Baoyintu group of biotite-plagioclase gneiss(Pt1by),upper Permian Linxi formation of sandy slate(P2l),and the Hercynian Qianjinchang pluton of biotite granite.展开更多
The Gejiu tin polymetallic deposits are located in the southeastern part of Yunnan Province in China. A detailed electronic microprobe study has been carried out to document geochemical compositions of tourmalines fro...The Gejiu tin polymetallic deposits are located in the southeastern part of Yunnan Province in China. A detailed electronic microprobe study has been carried out to document geochemical compositions of tourmalines from the deposits. The results indicate a systematic change of mineral geochemical compositions, which might be used as a mineral geochemical tracer for post-magmatic hydrothermal fluid, basin fluid and their mixture. The tourmalines from granite are schori with Fe/ (Fe+Mg) ratios of 0.912-1.00 and Na/(Na+Ca) ratios of 0.892-0.981. Tourmalines as an inclusion in quartz from the ore bodies are dravite with Fe/(Fe+Mg) ratios of 0.212-0.519 and Na/(Na+Ca) ratios of 0.786--0.997. Tourmalines from the country rocks are dravite with Fe/(Fe+Mg) ratios of 0.313--0.337 and Na/(Na+Ca) ratio of 0.599-0.723. Tourmalines from cassiterite-tourmaline veins that occur in crannies within the country rocks show distinct optical zoning with alternate occurrence of dravite and schorl, Fe/(Fe+Mg)=0.374-0.843, Na/(Na+Ca)=0.538-0.987. It suggests that schorl in granite and dravite in carbonatite are related to magmatic fluid and basin fluid respectively. When magmatic fluid rose up and entered into crannies of the country rocks, consisting mainly of carbonatite, basin fluid would be constantly added to the magmatic fluid. The two types of fluid were mixed in structural crannies of the sedimentary basin accompanied with periodic geochemical oscillations to form material records in chemical composition zonings of tourmalines.展开更多
In order to get a better understanding of metallogeny, the geochemical characteristics of REE and trace element for Gejiu tin polymetallic deposits were studied by comparing concentrations of REE and trace elements in...In order to get a better understanding of metallogeny, the geochemical characteristics of REE and trace element for Gejiu tin polymetallic deposits were studied by comparing concentrations of REE and trace elements in different type ores and rocks, including skarn-type ore, bedded-type ore, vein-type ore, altered granite, country rocks. Results of this study indicated that the metallogenic matters for different type ores in the study area might be derived from the same origin source, which may be mainly related to granitic activities. Furthermore, there are some differences in concentrations of REE in different ores due to their different depositional mechanism during that time. LREE concentrations were enriched relatively in the vein-type ores and the bedded-type ores with relatively low total REE concentrations, whereas total REE concentrations were higher in the skarn-type ores with LREE and HREE concentrations in wide variation ranges.展开更多
The southwestern Fujian depression belt(SFDB)is an economically important Mesozoic Fe metallogenic belt in South China and is renowned for its Makeng-type Fe deposits,in which stratified skarn Fe orebodies generally o...The southwestern Fujian depression belt(SFDB)is an economically important Mesozoic Fe metallogenic belt in South China and is renowned for its Makeng-type Fe deposits,in which stratified skarn Fe orebodies generally occur in or near the contact zone between late Paleozoic carbonate sequences and Mesozoic granites.However,the genesis and geodynamic setting of these deposits remain unclear because the characteristics of the widely distributed Pb–Zn–Cu and Mo orebodies in these deposits and the temporal,spatial,and genetic relationships between magmatism and mineralization are poorly defined.The Dapai Fe polymetallic deposit in the SFDB is a typical example of Makeng-type Fe deposits but also has regional significance,whereby the stratified skarn Fe orebodies have overprinted the stratabound Pb–Zn–Cu mineralization followed by final fissure-filling by vein-disseminated Mo mineralization.A detailed geological investigation suggests that episodic magmatic–hydrothermal events were involved in the formation process of the Dapai Fe polymetallic deposit.Pyrite and sphalerite from the Pb–Zn–Cu orebodies yield an Rb–Sr isochron age of 175.5±3.3 Ma,which is regarded as the timing of Pb–Zn–Cu mineralization.Zircon grains from Fe-mineralized granodiorite porphyry and Mo-mineralized monzogranite yield weighted-mean 206Pb/238U ages of 146.3±0.9 Ma and 131.7±0.4 Ma,interpreted as the timings of Fe and Mo mineralization,respectively.Six zircons from granodiorite also yield a 206Pb/238U model age cluster of184 Ma,which coincides reasonably with the timing of Pb–Zn–Cu mineralization and implies the existence of an unidentified ore-related intrusion in the Dapai deposit.Five further zircons from the porphyritic granodiorite yield an age cluster of-150 Ma,consistent with the timing of Fe mineralization.Galena,pyrite,and sphalerite from the Dapai and Makeng deposits have similar S–Pb isotopic compositions and suggest a magmatic source.Combining our results with published isotopic data for the SFDB,we suggest that the Pb–Zn–Cu mineralization in this area was derived from crustal magmas that mixed with mantle-derived magma prior to emplacement.The d56Fe and d57Fe values of magnetite from Dapai and Makeng are both slightly lower than those of the orerelated granites,suggesting that Fe in the initial fluid in both deposits was derived mainly from coeval granitic rocks.The Fe isotopic variation between intrusions and skarn Fe orebodies is interpreted as resulting from mass fractionation that occurred during fluid exsolution from melt.Contents of Re in molybdenite from published data for the SFDB indicate crust–mantle mixed sources of Mo and Re.The Makeng-type Fe polymetallic deposits formed as a result of three magmatic–hydrothermal episodes,generating Pb–Zn–Cu mineralization at 185–160 Ma,Fe–Mo mineralization at 150–140 Ma,and Mo–Fe mineralization at 135–130 Ma.The different metal associations formed during multiple stages of magmatism caused by ongoing subduction and rollback and/or retreat of the paleo-Pacific Plate.展开更多
1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platfor...1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platform.The ore-bodies of Dongshengmiao deposits are mainly hosted in the second Formation of Langshan Group.There are some studies on the geological characteristics(Peng et al.,2004),geological and展开更多
The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the ...The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the Jurassic-Cretaceous quartz diorite porphyry,while the genesis of this deposit is unclear.This study focused on geological and mineralogical characteristics,in-situ trace elements and S-Pb isotopes of three generations of pyrite of the Huxu deposit to clarify the distribution of trace elements in pyrite,ore-forming fluid and material sources,and genetic types of the deposit.The mineralization stage of the deposit can be divided into quartz-pyrite stage(S1),quartz-pyrite-hematite stage(S2),quartz-polymetallic sulfide stage(S3)and quartz-hematite stage(S4),with the corresponding pyrite being divided into three generations(Py1-Py3).in-situ trace element data of pyrite show that Au in pyrite mainly exists in the form of solid solution(Au^(+)),and the content is relatively low at all stages(0.18 ppm for Py1,0.32 ppm for Py2,0.68 ppm for Py3),while Pb and Zn mainly exist as sulfide inclusions in the pyrite.S-Pb isotopes show that the sulfur and ore-forming material of this deposit are mainly sourced from magma.The mineral association,mineral textures and trace elements in different stages of pyrite indicate that fluid boiling and fluid mixing are the key factors of native gold precipitation in S2 and S4,respectively,while water-rock interaction controlled the precipitation of Pb-Zn sulfides.These integrating with geological characteristics suggests that the deposit should be an intermediate sulfidation epithermal deposit.展开更多
The Kaerqueka polymetallic deposit, Qinghai, China, is one of the typical skarn-type polymetallic ore deposits in the Qimantage metallogenic belt. The dynamic mechanism on the formation of the Kaerqueka polymetallic d...The Kaerqueka polymetallic deposit, Qinghai, China, is one of the typical skarn-type polymetallic ore deposits in the Qimantage metallogenic belt. The dynamic mechanism on the formation of the Kaerqueka polymetallic deposit is always an interesting topic of research. We used the finite difference method to model the mineralizing process of the chalcopyrite in this region with considering the field geological features, mineralogy and geochemistry. In particular, the modern mineralization theory was used to quantitatively estimate the related chemical reactions associated with the chalcopyrite formation in the Kaerqueka polymetallic deposit. The numerical results indicate that the hydrothermal fluid flow is a key controlling factor of mineralization in this area and the temperature gradient is the driving force of pore-fluid flow. The metallogenic temperature of chalcopyrite in the Kaerqueka polymetallic deposit is between 250 and 350 ℃. The corresponding computational results have been verified by the field observations. It has been further demonstrated that the simulation results of coupled models in the field of emerging computational geosciences can enhance our understanding of the ore-forming processes in this area.展开更多
The Gejiu (个旧) deposit is a superlarge tin-copper polymetallic ore-forming concentration area characterized by excellent metallogenic geological settings and advantageous ore-controlling factors. The deposit displ...The Gejiu (个旧) deposit is a superlarge tin-copper polymetallic ore-forming concentration area characterized by excellent metallogenic geological settings and advantageous ore-controlling factors. The deposit displays diverse mineralization properties due to different minerals and mineral deposit types. Based on the principal metallogenic factors, metallogenic mechanisms, mineralized components, and occurrence of mineral deposits or ore bodies, the Gejiu mineral district can be divided into 2 combinations of metallogenic series, 4 metallogenic series, 8 subseries, and 27 mineral deposit types. Spatial zonality is evident. The distribution regularity of the elements in both plane and section is Be-W, Sn (Cu, Mo, Bi, Be)-Sn, Pb, Ag-Pb, Zn around a granitic intrusion. The metallogenic epoch is mainly concentrated in the late Yanshanian. During this period, large-scale metallogenic processes related to movement caused by tectonics and magmatism occurred, and a series of magmatic hydrothermal deposits formed. The ore-forming processes can be divided into 4 stages: the silicate stage, the oxide stage, the sulphide stage, and the carbonate stage. Based on the orderliness and diversity (in terms of time, space, and genesis) of the mineralization, the authors have developed a comprehensive spectrum of ore deposits in the Gejiu area. This newly proposed diversity of mineralization and the spectrum developed in this work are useful not only for interpreting the genesis of the Gejiu deposit but also for improving mineral exploration in the area, and in particular, for finding large deposits.展开更多
Objective In recent years, a series of tungsten prospecting breakthroughs have been made in the southern Qinling Mountains. Especially, a new deposit type with a scheelite -beryl-molybdenite assemblage in the Zhen'a...Objective In recent years, a series of tungsten prospecting breakthroughs have been made in the southern Qinling Mountains. Especially, a new deposit type with a scheelite -beryl-molybdenite assemblage in the Zhen'an area of Shaanxi Province was firstly discovered. This deposit is currently in a detailed investigation stage, and no detailed study has been yet conducted. This work selected one molybdenite sample from the Be (W) ores in this deposit for Re-Os isotope measurements to define the time limit of tungsten and beryllium mineralization, and to further reveal the ore-forming geological setting of rare metals in the southern Qinling region.展开更多
The Lanping Basin in the Nujiang-Lancangjiang-Jinshajiang (the Sanjiang) area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of l...The Lanping Basin in the Nujiang-Lancangjiang-Jinshajiang (the Sanjiang) area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of large unique sediment-hosted Pb-Zn polymetallic deposits or ore districts, such as the Baiyangping ore concentration area which is one of the representative ore district. The Baiyangping ore concentration area can be divided into the east and west ore belts, which were formed in a folded tectogene of the India-Asia continental coUisional setting and was controlled by a large reverse fault. Field observations reveal that the Mesozoic and Cenozoic sedimentary strata were outcropped in the mining area, and that the orebodies are obviously controlled by faults and hosted in sandstone and carbonate rocks. However, the oreforming elements in the east ore belt are mainly Pb-Zn -Sr-Ag, while Pb-Zn-Ag-Cu-Co elements are dominant in the west ore belt. Comparative analysis of the C-O-Sr-S-Pb isotopic compositions suggest that both ore belts had a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata; the ore- forming fluids were originated from formation water and precipitate water, which belonged to basin brine fluid system; sulfur was from organic thermal chemical sulfate reduction and biological sulfate reduction; the metal mineralization material was from sedimentary strata and basement, but the difference of the material source of the basement and the strata and the superimposed mineralization of the west ore belt resulted in the difference of metallogenic elements between the eastern and western metallogenic belts. The Pb-Zn mineralization age of both ore belts was contemporary and formed in the same metaliogenetic event. Both thrust formed at the same time and occurred at the Early Oligocene, which is consistent with the age constrained by field geological relationship.展开更多
The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle ...The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle Devonian, and its geological occurrence is consistent with the wall rocks. A large number of spheroidal pyrite aggregates are found unevenly distributed in the ores. The spheroidal aggregates are made up of kernels and concentric rings. The kernels are composed of approximately epigranular pyrite nanocrystals, while the rings are composed of accumulated pyrite microcrystals growing along the radial direction. The spheroidal pyrite aggregate and its outer zones can be divided into five areas(A–E). The results of electron probe micro analysis(EPMA) show that from the zone A1 to B, Co/Ni 〈1, the sum of Co and Ni is 0.08%–0.26%, S/Fe increases from 2.06 to 2.15. While from the zone C to E, Ni cannot be detected and S/Fe decreases from 2.22 to 2.08. Powder X-ray diffraction(XRD) analysis in the micro zone shows obvious crystalline characteristics in the aggregates. Moving from the inside outwards, the maximum diffraction peak intensity of the(111) and(220) crystal planes of pyrite increases, and the crystallinity improves. The degree of change in the(111) plane is the most prominent. Considering the theory of crystal growth along with the geologic features of the depositional environment where the spheroidal pyrite aggregates developed, we confirm that the spheroidal aggregates are the result of nano-micro crystalline gathering and growth occurring by the following sequence of processes:nano-crystalline nucleation and growth, gathering into a ball, oriented growth of microcrystals, continuous accumulation, and adjustment of grain boundaries. The formation of the spheroidal pyrite aggregates in the late Qiziqiao Formation of the Middle Devonian occurred in a neutral to weak alkaline and reductive sedimentary environment in the normal oxygen-rich shallowwater carbonate platform edge. The variations in the S/Fe ratio and crystallisation characteristics indicate that during pyrite crystal growth, the sulphur fugacity was high locally and rose constantly, the degree of supersaturation decreased locally and the growth environment was stable relatively.展开更多
The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part ...The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part of Nanling polymetallic deposit belt.The outcropping stratas consist of upper Devonian Shetianqiao,Xikuangshan Formation,Lower Carboniferous Menggong’ao,Shidengzi,Ceshui,and Zimenqiao Formation.Igneous rocks in the Baoshan ore area mainly comprise granodiorite porphyry.Furthermore,the radio isotopic age ranges from 123 Ma to 183 Ma,belonging to the early to middle Yanshanian.展开更多
The Wenyu copper polymetallic deposit, with proven reserves of about 0.23 Mt Cu, 394 t Ag and 0.04 Mt Pb, is located in the central part of the Lancangjiang volcanic rock belt (Fig. l a), which is one of the most po...The Wenyu copper polymetallic deposit, with proven reserves of about 0.23 Mt Cu, 394 t Ag and 0.04 Mt Pb, is located in the central part of the Lancangjiang volcanic rock belt (Fig. l a), which is one of the most potential copper polymetallic exploration areas in SW China.展开更多
The Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit(20000 t Sn at 0.27%,236 t Ag at 122.89 g/t,15000 t Pb at 0.84%,and 38000 t Zn at 1.43%)is located in the Wandashan Terrane of the easternmost segment of the Central A...The Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit(20000 t Sn at 0.27%,236 t Ag at 122.89 g/t,15000 t Pb at 0.84%,and 38000 t Zn at 1.43%)is located in the Wandashan Terrane of the easternmost segment of the Central Asian Orogenic Belt.The timing of Sn-Pb-Zn-Ag polymetallic mineralization remains unclear due to a lack of precise isotope dating directly conducted on ore minerals.The authors herein report that the LA-ICP-MS U-Pb ages of cassiterite and zircon from the granite porphyry in the Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit are 101.4±7.9 Ma and 115.4±1.0 Ma,respectively,indicating that Sn mineralization and magmatism occurred during the Early Cretaceous.The granite porphyry belongs to the subalkaline series peraluminous I-type granites that are depleted in Nb,Ta,and Ti and enriched in Rb,Th,U,and Pb.TheεHf(t)values of the granite porphyry range from 0.9 to 7.4,with an average of about 5.6 and two-stage model ages(T_(DM2))of 705–1116 Ma,with an average age of 819 Ma.The ε_(Nd)(t)values of the apatites are–1.60–0.45,with an average of–0.9,and two-stage model ages(T_(DM2))of 872–1040 Ma,with an average age of 983 Ma.The Nd-Hf isotope data indicate that the magma may have been derived from the partial melting of juvenile crustal material.展开更多
Objective The Sachakou Pb-Zn polymetallic deposit is located in Hetian County, Xinjiang (geographical coordinates of E78° 57' 54.30"-78°59' 53.63", N34° 39' 27.50"-34° 40' 57.21"). It be...Objective The Sachakou Pb-Zn polymetallic deposit is located in Hetian County, Xinjiang (geographical coordinates of E78° 57' 54.30"-78°59' 53.63", N34° 39' 27.50"-34° 40' 57.21"). It belongs to the West Kunlun orogenic belt on the northwest edge of the Qinghai-Tibet Plateau and is connected to the Sanjiang orogenic belt to the south (Spurlin et al., 2005). In recent years, a series of Pb-Zn mineralized spots and deposits have been discovered in this area one after another, which is called the Huoshaoyun ore concentration area. Among them, the Sachakou Pb-Zn deposit has reserves up to140 Mt, which has reached a large scale. However, the study on the genesis of deposits in this area has only just begun. This work studied the genesis ofthis Pb-Zn deposit in order to provide new ideas for the genesis of regional deposits and regional prospecting.展开更多
The Nage Cu-Pb polymetallic deposit is located in the transitional zone of the Yangtze craton and cathaysia,that is the southwest of Jiangnan orogenic belt. The mainly strata are Wentong formation of Mesoproterozoic S...The Nage Cu-Pb polymetallic deposit is located in the transitional zone of the Yangtze craton and cathaysia,that is the southwest of Jiangnan orogenic belt. The mainly strata are Wentong formation of Mesoproterozoic Sibo group and the Jialu formation(Qbj) ,Wuye formation(Qbw) ,Fanzhao formation(Qbf) and Gongdong formation(Qbg) of the Neoproterozoic Qingbaikou System Xiajiang group.展开更多
The Beiya porphyry-skarn gold-polymetallic deposit is one of the largest gold deposits in China and it also contains significant amounts of silver and base metals.The ore-bearing monzonitic granite porphyry occurs as ...The Beiya porphyry-skarn gold-polymetallic deposit is one of the largest gold deposits in China and it also contains significant amounts of silver and base metals.The ore-bearing monzonitic granite porphyry occurs as a stock,of which the skarn type gold-copper-iron ore bodies are controlled by the contact zone between alkali-rich monzonitic granite porphyry and the limestone,and the gold-silver polymetallic mineralization is controlled by interlayer structure.Alteration and mineralization occur around the intrusion and exterior of monzonitic granite porphyry.Ore mineral formation sequence is as follows:skarn minerals→magnetite→pyrite→chalcopyrite/bornite+pyrite+gold→pyrite+galena+gold(silver).Petrographic studies of fluid inclusions indicate that the following types of inclusions exist in the pre-mineralization quartz-pyrite stage:gas-liquid two-phase inclusions(L-type),three-phase inclusions with daughter minerals(D-type)and gas-rich inclusions(V-type).The colorless transparent quartz in the main gold-chalcopyrite-pyrite stage mainly consists of L-type and V-type inclusions,whereas the inclusions in the late gold-silver-galena stage are mainly L-type.The evolution of ore-forming fluids shows a trend from high temperature,high salinity to medium-low temperature and low salinity.Medium-low density fluids play a dominant role in mineral component migration and transportation.Fluid cooling and boiling are the main mechanisms of gold-copper precipitation,while the involvement of atmospheric water and pH reduction are the main mechanisms of gold-silver polymetallic precipitation.The fluids in the quartz-pyrite stage before mineralization and the main gold-chalcopyrite-pyrite stage are dominated by magmatic water,while in the gold-silver-galena stage the fluids are dominated by atmospheric water.Isotope tracers show that S and Pb are mainly derived from monzonitic granite porphyry,not from limestone of the Beiya Formation.展开更多
1 Introduction Southeast Yunnan is the convergent place of the Yangtze,Indochina blocks(Xu Wei,et al.2008).The Hongshiyan Pb-Zn-Cu polymetallic deposit is located in Wenshan Prefecture,Yunnan Province.It is a typical ...1 Introduction Southeast Yunnan is the convergent place of the Yangtze,Indochina blocks(Xu Wei,et al.2008).The Hongshiyan Pb-Zn-Cu polymetallic deposit is located in Wenshan Prefecture,Yunnan Province.It is a typical large sized VMS-type deposit discovered in recent years.The major ore minerals are sphalerite,galena,chalcopyrite ect.展开更多
Compared with the porphyry Cu-epithermal Au mineralization system,detailed studies on the porphyry Mo-epithermal Pb–Zn–Ag–Au mineralization are rare due to limited exposures.The Shipingchuan polymetallic deposit,lo...Compared with the porphyry Cu-epithermal Au mineralization system,detailed studies on the porphyry Mo-epithermal Pb–Zn–Ag–Au mineralization are rare due to limited exposures.The Shipingchuan polymetallic deposit,located in the South China Mo Province(SCMP)represents a typical example containing both porphyry Mo and epithermal Pb–Zn–Ag mineralization.The Mo mineralization mainly occurs as molybdenite-quartz veins in veinlets or as disseminated molybdenite within the potassic,silicic,and sericitic syenogranite.The Pb–Zn–Ag mineralization is characterized by veinlet-type sphalerite–galena–pyrite–quartz–calcite vein within the volcanic rocks accompanied with silicifi cation and propylitization.Five molybdenite samples yield a Re–Os isochron age of 104.7±0.7 Ma that is consistent with the zircon age(107.5±2.1 Ma)of the ore-bearing syenogranite within errors.Together with previous reported Ar–Ar ages(106.6–121.8 Ma)of Pb–Zn–Ag related volcanic rocks,the Mo and Pb–Zn–Ag mineralization belong to a magmatic-hydrothermal event in the Early Cretaceous.Meanwhile,the total Re contents of molybednite range from 1.28 to 45.55 ppm,indicating the ore-forming materials were from a mixture between the mantle and crustal material.Moreover,previous sulfur isotopic values(3.7–4.3‰)of the pyrites from the porphyry Mo mineralization were consistent with the reported range of 4.0–6.1‰of the sphalerites from the Pb–Zn–Ag mineralization,implying that the sulfur of two-types of mineralization was derived from magma.The above-mentioned spatial,temporal,and isotopic lines of evidence suggest that the Mo and Pb–Zn–Ag mineralization of the Shipingchuan deposit was formed from the same metallogenic system.In consideration of regional tectonic evolution history,we propose that the porphyry Mo-epithermal Pb–Zn–Ag mineralization formed in an extensional tectonic setting caused by the continued rollback and the eventual slab break-off of the subducting PaleoPacifi c plate.展开更多
The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies...The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies are hosted by granodiorites, porphyritic granites and tourmalinegarnet-quartz-muscovite metasomatic rocks. These orebodies are surrounded by wall rocks dominated by the Tukuringra Complex granodiorites, porphyritic granites, and gneissic granodiorites. The alteration includes silicification and garnet, sericitization chloritization, carbonatization and kaollinization. LA-ICP-MS U-Pb zircon dating indicates that the gold mineralization can be divided into two stages in the Berezitovoe polymetallic gold deposit(at 363.5 ± 1.5 Ma, and133.4± 0.5).Hornblende-plagioclase gneisses of the Mogocha Group in the study area underwent Paleoproterozoic metamorphism(at 1870 ± 7.8 and 2400 ± 13 Ma), gneissic granodiorite of the Tukuringra Complex yields a late Paleozoic magmatic age(at 379.2 ± 1.1 Ma),and subalkaline porphyritic granitoid of the Amudzhikan Complex yield late Mesozoic magmatic ages(133-139 and 150-163 Ma). Granodiorites of the Tukuringra Complex in the study area have high concentrations of SiO_2(average of 60.9 wt%), are aluminum-oversaturated(average A/CNK of 1.49), are enriched in the large ion lithophile elements(e.g.,K, Rb, and Ba), U, Th, and Pb, are depleted in high field strength elements(e.g., Ta, Nb, and Ti), and have slightly negative Eu and no Ce anomalies in chondrite-normalized rare earth element diagrams.Fluid inclusions from quartz veins include three types: aqueous two-phase, CO2-bearing three-phase,and pure CO2. Aqueous two-phase inclusions homogenize at 167℃-249℃ and have salinities of 4.32%-9.47% NaCl equivalent, densities of 0.86-0.95 g/cm^3, and formed at depths of 0.52-0.94 km. In comparison, the CO2-bearing three-phase inclusions have homogenization temperatures of 265℃-346℃,salinities of 7.14%-11.57% NaCl equivalent, and total densities of 0.62-0.67 g/cm^3. The geochemical and zircon U-Pb data and the regional tectonic evolution of the study area, show that the Berezitovoe polymetallic gold deposit formed in an island arc or active continental margin setting, most probably related to late Paleozoic subduction of Okhotsk Ocean crust beneath the Siberian Plate.展开更多
文摘1 Geology Daolundaba copper polymetallic deposit occurs in West Ujimqin Banner,the Xilin Gol League of Inner Mongolia,along the west side of South part of Daxinganling ore belt,whose tectonic position just lies at the junction of Siberian Block in the south part,North China Block in the north and Songliao block in the east.The Daolundaba copper polymetallic deposit is hosted by the Lower Proterozoic Baoyintu group of biotite-plagioclase gneiss(Pt1by),upper Permian Linxi formation of sandy slate(P2l),and the Hercynian Qianjinchang pluton of biotite granite.
基金supported by "Technology of Comprehensive Prospecting and Exploitability for Elements in Crisis Mines" (Grant No. 2008EG115074)a special fund managed by the Ministry of Science and Technology for technical R&D of scientific research institutions, and the Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences
文摘The Gejiu tin polymetallic deposits are located in the southeastern part of Yunnan Province in China. A detailed electronic microprobe study has been carried out to document geochemical compositions of tourmalines from the deposits. The results indicate a systematic change of mineral geochemical compositions, which might be used as a mineral geochemical tracer for post-magmatic hydrothermal fluid, basin fluid and their mixture. The tourmalines from granite are schori with Fe/ (Fe+Mg) ratios of 0.912-1.00 and Na/(Na+Ca) ratios of 0.892-0.981. Tourmalines as an inclusion in quartz from the ore bodies are dravite with Fe/(Fe+Mg) ratios of 0.212-0.519 and Na/(Na+Ca) ratios of 0.786--0.997. Tourmalines from the country rocks are dravite with Fe/(Fe+Mg) ratios of 0.313--0.337 and Na/(Na+Ca) ratio of 0.599-0.723. Tourmalines from cassiterite-tourmaline veins that occur in crannies within the country rocks show distinct optical zoning with alternate occurrence of dravite and schorl, Fe/(Fe+Mg)=0.374-0.843, Na/(Na+Ca)=0.538-0.987. It suggests that schorl in granite and dravite in carbonatite are related to magmatic fluid and basin fluid respectively. When magmatic fluid rose up and entered into crannies of the country rocks, consisting mainly of carbonatite, basin fluid would be constantly added to the magmatic fluid. The two types of fluid were mixed in structural crannies of the sedimentary basin accompanied with periodic geochemical oscillations to form material records in chemical composition zonings of tourmalines.
文摘In order to get a better understanding of metallogeny, the geochemical characteristics of REE and trace element for Gejiu tin polymetallic deposits were studied by comparing concentrations of REE and trace elements in different type ores and rocks, including skarn-type ore, bedded-type ore, vein-type ore, altered granite, country rocks. Results of this study indicated that the metallogenic matters for different type ores in the study area might be derived from the same origin source, which may be mainly related to granitic activities. Furthermore, there are some differences in concentrations of REE in different ores due to their different depositional mechanism during that time. LREE concentrations were enriched relatively in the vein-type ores and the bedded-type ores with relatively low total REE concentrations, whereas total REE concentrations were higher in the skarn-type ores with LREE and HREE concentrations in wide variation ranges.
基金funded by the projects of China Geological Survey(Grant Nos.12120113089600,1212011085472,and 12120114028701)。
文摘The southwestern Fujian depression belt(SFDB)is an economically important Mesozoic Fe metallogenic belt in South China and is renowned for its Makeng-type Fe deposits,in which stratified skarn Fe orebodies generally occur in or near the contact zone between late Paleozoic carbonate sequences and Mesozoic granites.However,the genesis and geodynamic setting of these deposits remain unclear because the characteristics of the widely distributed Pb–Zn–Cu and Mo orebodies in these deposits and the temporal,spatial,and genetic relationships between magmatism and mineralization are poorly defined.The Dapai Fe polymetallic deposit in the SFDB is a typical example of Makeng-type Fe deposits but also has regional significance,whereby the stratified skarn Fe orebodies have overprinted the stratabound Pb–Zn–Cu mineralization followed by final fissure-filling by vein-disseminated Mo mineralization.A detailed geological investigation suggests that episodic magmatic–hydrothermal events were involved in the formation process of the Dapai Fe polymetallic deposit.Pyrite and sphalerite from the Pb–Zn–Cu orebodies yield an Rb–Sr isochron age of 175.5±3.3 Ma,which is regarded as the timing of Pb–Zn–Cu mineralization.Zircon grains from Fe-mineralized granodiorite porphyry and Mo-mineralized monzogranite yield weighted-mean 206Pb/238U ages of 146.3±0.9 Ma and 131.7±0.4 Ma,interpreted as the timings of Fe and Mo mineralization,respectively.Six zircons from granodiorite also yield a 206Pb/238U model age cluster of184 Ma,which coincides reasonably with the timing of Pb–Zn–Cu mineralization and implies the existence of an unidentified ore-related intrusion in the Dapai deposit.Five further zircons from the porphyritic granodiorite yield an age cluster of-150 Ma,consistent with the timing of Fe mineralization.Galena,pyrite,and sphalerite from the Dapai and Makeng deposits have similar S–Pb isotopic compositions and suggest a magmatic source.Combining our results with published isotopic data for the SFDB,we suggest that the Pb–Zn–Cu mineralization in this area was derived from crustal magmas that mixed with mantle-derived magma prior to emplacement.The d56Fe and d57Fe values of magnetite from Dapai and Makeng are both slightly lower than those of the orerelated granites,suggesting that Fe in the initial fluid in both deposits was derived mainly from coeval granitic rocks.The Fe isotopic variation between intrusions and skarn Fe orebodies is interpreted as resulting from mass fractionation that occurred during fluid exsolution from melt.Contents of Re in molybdenite from published data for the SFDB indicate crust–mantle mixed sources of Mo and Re.The Makeng-type Fe polymetallic deposits formed as a result of three magmatic–hydrothermal episodes,generating Pb–Zn–Cu mineralization at 185–160 Ma,Fe–Mo mineralization at 150–140 Ma,and Mo–Fe mineralization at 135–130 Ma.The different metal associations formed during multiple stages of magmatism caused by ongoing subduction and rollback and/or retreat of the paleo-Pacific Plate.
文摘1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platform.The ore-bodies of Dongshengmiao deposits are mainly hosted in the second Formation of Langshan Group.There are some studies on the geological characteristics(Peng et al.,2004),geological and
基金jointly supported by the foundation from Department of Science and Technology of Jiangxi Province(No.20232BAB213064)National Natural Science Foundation of China(No.42102088)foundation from the State Key Laboratory of Nuclear Resources and Environment(2022NRE33)。
文摘The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the Jurassic-Cretaceous quartz diorite porphyry,while the genesis of this deposit is unclear.This study focused on geological and mineralogical characteristics,in-situ trace elements and S-Pb isotopes of three generations of pyrite of the Huxu deposit to clarify the distribution of trace elements in pyrite,ore-forming fluid and material sources,and genetic types of the deposit.The mineralization stage of the deposit can be divided into quartz-pyrite stage(S1),quartz-pyrite-hematite stage(S2),quartz-polymetallic sulfide stage(S3)and quartz-hematite stage(S4),with the corresponding pyrite being divided into three generations(Py1-Py3).in-situ trace element data of pyrite show that Au in pyrite mainly exists in the form of solid solution(Au^(+)),and the content is relatively low at all stages(0.18 ppm for Py1,0.32 ppm for Py2,0.68 ppm for Py3),while Pb and Zn mainly exist as sulfide inclusions in the pyrite.S-Pb isotopes show that the sulfur and ore-forming material of this deposit are mainly sourced from magma.The mineral association,mineral textures and trace elements in different stages of pyrite indicate that fluid boiling and fluid mixing are the key factors of native gold precipitation in S2 and S4,respectively,while water-rock interaction controlled the precipitation of Pb-Zn sulfides.These integrating with geological characteristics suggests that the deposit should be an intermediate sulfidation epithermal deposit.
基金Project(2017YFC0601503)supported by the National Key R&D Program of ChinaProjects(41872249,41472302,41772348)supported by the National Natural Science Foundation of China
文摘The Kaerqueka polymetallic deposit, Qinghai, China, is one of the typical skarn-type polymetallic ore deposits in the Qimantage metallogenic belt. The dynamic mechanism on the formation of the Kaerqueka polymetallic deposit is always an interesting topic of research. We used the finite difference method to model the mineralizing process of the chalcopyrite in this region with considering the field geological features, mineralogy and geochemistry. In particular, the modern mineralization theory was used to quantitatively estimate the related chemical reactions associated with the chalcopyrite formation in the Kaerqueka polymetallic deposit. The numerical results indicate that the hydrothermal fluid flow is a key controlling factor of mineralization in this area and the temperature gradient is the driving force of pore-fluid flow. The metallogenic temperature of chalcopyrite in the Kaerqueka polymetallic deposit is between 250 and 350 ℃. The corresponding computational results have been verified by the field observations. It has been further demonstrated that the simulation results of coupled models in the field of emerging computational geosciences can enhance our understanding of the ore-forming processes in this area.
文摘The Gejiu (个旧) deposit is a superlarge tin-copper polymetallic ore-forming concentration area characterized by excellent metallogenic geological settings and advantageous ore-controlling factors. The deposit displays diverse mineralization properties due to different minerals and mineral deposit types. Based on the principal metallogenic factors, metallogenic mechanisms, mineralized components, and occurrence of mineral deposits or ore bodies, the Gejiu mineral district can be divided into 2 combinations of metallogenic series, 4 metallogenic series, 8 subseries, and 27 mineral deposit types. Spatial zonality is evident. The distribution regularity of the elements in both plane and section is Be-W, Sn (Cu, Mo, Bi, Be)-Sn, Pb, Ag-Pb, Zn around a granitic intrusion. The metallogenic epoch is mainly concentrated in the late Yanshanian. During this period, large-scale metallogenic processes related to movement caused by tectonics and magmatism occurred, and a series of magmatic hydrothermal deposits formed. The ore-forming processes can be divided into 4 stages: the silicate stage, the oxide stage, the sulphide stage, and the carbonate stage. Based on the orderliness and diversity (in terms of time, space, and genesis) of the mineralization, the authors have developed a comprehensive spectrum of ore deposits in the Gejiu area. This newly proposed diversity of mineralization and the spectrum developed in this work are useful not only for interpreting the genesis of the Gejiu deposit but also for improving mineral exploration in the area, and in particular, for finding large deposits.
基金financially supported by the China Postdoctoral Science Foundation(grant 2017M610960)China Geological Survey(grants No.DD20160346 and DD20160055)
文摘Objective In recent years, a series of tungsten prospecting breakthroughs have been made in the southern Qinling Mountains. Especially, a new deposit type with a scheelite -beryl-molybdenite assemblage in the Zhen'an area of Shaanxi Province was firstly discovered. This deposit is currently in a detailed investigation stage, and no detailed study has been yet conducted. This work selected one molybdenite sample from the Be (W) ores in this deposit for Re-Os isotope measurements to define the time limit of tungsten and beryllium mineralization, and to further reveal the ore-forming geological setting of rare metals in the southern Qinling region.
基金granted by the National Natural Science Foundation of China(grants No.41302067,41472067 and 41403043)the Fundamental Research Funds of Chinese Academy of Geological Sciences(grant No.YYWF201614 and 09 program of Institute of Geomechanics)IGCP/SIDA–600,and China Geological Survey(grant No.DD20160053)
文摘The Lanping Basin in the Nujiang-Lancangjiang-Jinshajiang (the Sanjiang) area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of large unique sediment-hosted Pb-Zn polymetallic deposits or ore districts, such as the Baiyangping ore concentration area which is one of the representative ore district. The Baiyangping ore concentration area can be divided into the east and west ore belts, which were formed in a folded tectogene of the India-Asia continental coUisional setting and was controlled by a large reverse fault. Field observations reveal that the Mesozoic and Cenozoic sedimentary strata were outcropped in the mining area, and that the orebodies are obviously controlled by faults and hosted in sandstone and carbonate rocks. However, the oreforming elements in the east ore belt are mainly Pb-Zn -Sr-Ag, while Pb-Zn-Ag-Cu-Co elements are dominant in the west ore belt. Comparative analysis of the C-O-Sr-S-Pb isotopic compositions suggest that both ore belts had a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata; the ore- forming fluids were originated from formation water and precipitate water, which belonged to basin brine fluid system; sulfur was from organic thermal chemical sulfate reduction and biological sulfate reduction; the metal mineralization material was from sedimentary strata and basement, but the difference of the material source of the basement and the strata and the superimposed mineralization of the west ore belt resulted in the difference of metallogenic elements between the eastern and western metallogenic belts. The Pb-Zn mineralization age of both ore belts was contemporary and formed in the same metaliogenetic event. Both thrust formed at the same time and occurred at the Early Oligocene, which is consistent with the age constrained by field geological relationship.
基金granted by the National Natural Science Foundation of China (Grant No. 41172047, 41272062)the Open Fund of the State Key Laboratory of Ore Deposit Geochemistry (Institute of Geochemistry, Chinese Academy of Sciences, Guiyang) (Grant No. 201308)
文摘The Baiyunpu deposit lies in the southwest plunging Dachengshan anticline in central Hunan, which is a large Pb-Zn polymetallic deposit. The orebodies were surrounded by the Qiziqiao Formation limestone in the Middle Devonian, and its geological occurrence is consistent with the wall rocks. A large number of spheroidal pyrite aggregates are found unevenly distributed in the ores. The spheroidal aggregates are made up of kernels and concentric rings. The kernels are composed of approximately epigranular pyrite nanocrystals, while the rings are composed of accumulated pyrite microcrystals growing along the radial direction. The spheroidal pyrite aggregate and its outer zones can be divided into five areas(A–E). The results of electron probe micro analysis(EPMA) show that from the zone A1 to B, Co/Ni 〈1, the sum of Co and Ni is 0.08%–0.26%, S/Fe increases from 2.06 to 2.15. While from the zone C to E, Ni cannot be detected and S/Fe decreases from 2.22 to 2.08. Powder X-ray diffraction(XRD) analysis in the micro zone shows obvious crystalline characteristics in the aggregates. Moving from the inside outwards, the maximum diffraction peak intensity of the(111) and(220) crystal planes of pyrite increases, and the crystallinity improves. The degree of change in the(111) plane is the most prominent. Considering the theory of crystal growth along with the geologic features of the depositional environment where the spheroidal pyrite aggregates developed, we confirm that the spheroidal aggregates are the result of nano-micro crystalline gathering and growth occurring by the following sequence of processes:nano-crystalline nucleation and growth, gathering into a ball, oriented growth of microcrystals, continuous accumulation, and adjustment of grain boundaries. The formation of the spheroidal pyrite aggregates in the late Qiziqiao Formation of the Middle Devonian occurred in a neutral to weak alkaline and reductive sedimentary environment in the normal oxygen-rich shallowwater carbonate platform edge. The variations in the S/Fe ratio and crystallisation characteristics indicate that during pyrite crystal growth, the sulphur fugacity was high locally and rose constantly, the degree of supersaturation decreased locally and the growth environment was stable relatively.
基金Supported by the Program of Superseding Resources Prospecting in Crisis Mines in China(20089927)
文摘The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part of Nanling polymetallic deposit belt.The outcropping stratas consist of upper Devonian Shetianqiao,Xikuangshan Formation,Lower Carboniferous Menggong’ao,Shidengzi,Ceshui,and Zimenqiao Formation.Igneous rocks in the Baoshan ore area mainly comprise granodiorite porphyry.Furthermore,the radio isotopic age ranges from 123 Ma to 183 Ma,belonging to the early to middle Yanshanian.
基金financially supported by the China State Mineral Resources Investigation Program (Grant No.12120114013701 and 1212011120608)
文摘The Wenyu copper polymetallic deposit, with proven reserves of about 0.23 Mt Cu, 394 t Ag and 0.04 Mt Pb, is located in the central part of the Lancangjiang volcanic rock belt (Fig. l a), which is one of the most potential copper polymetallic exploration areas in SW China.
基金supported by the Chinese Central Government for Basic Scientific Research Operations in Commonwealth Research Institutes(KK 2013,KK2105)the Chinese Geological Survey Program(DD20190193,DD20211410)+1 种基金the National Key Research and Development Program of China(2017YFC0601303)the National Natural Science Foundation of China(41602075,41602066)。
文摘The Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit(20000 t Sn at 0.27%,236 t Ag at 122.89 g/t,15000 t Pb at 0.84%,and 38000 t Zn at 1.43%)is located in the Wandashan Terrane of the easternmost segment of the Central Asian Orogenic Belt.The timing of Sn-Pb-Zn-Ag polymetallic mineralization remains unclear due to a lack of precise isotope dating directly conducted on ore minerals.The authors herein report that the LA-ICP-MS U-Pb ages of cassiterite and zircon from the granite porphyry in the Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit are 101.4±7.9 Ma and 115.4±1.0 Ma,respectively,indicating that Sn mineralization and magmatism occurred during the Early Cretaceous.The granite porphyry belongs to the subalkaline series peraluminous I-type granites that are depleted in Nb,Ta,and Ti and enriched in Rb,Th,U,and Pb.TheεHf(t)values of the granite porphyry range from 0.9 to 7.4,with an average of about 5.6 and two-stage model ages(T_(DM2))of 705–1116 Ma,with an average age of 819 Ma.The ε_(Nd)(t)values of the apatites are–1.60–0.45,with an average of–0.9,and two-stage model ages(T_(DM2))of 872–1040 Ma,with an average age of 983 Ma.The Nd-Hf isotope data indicate that the magma may have been derived from the partial melting of juvenile crustal material.
基金the 8th Geological Brigade of Aksu,Xinjiang, the Institute of Geology of the Chinese Academy of Geological Sciencesthe Beijing Research Institute of Uranium Geology,CNNC
文摘Objective The Sachakou Pb-Zn polymetallic deposit is located in Hetian County, Xinjiang (geographical coordinates of E78° 57' 54.30"-78°59' 53.63", N34° 39' 27.50"-34° 40' 57.21"). It belongs to the West Kunlun orogenic belt on the northwest edge of the Qinghai-Tibet Plateau and is connected to the Sanjiang orogenic belt to the south (Spurlin et al., 2005). In recent years, a series of Pb-Zn mineralized spots and deposits have been discovered in this area one after another, which is called the Huoshaoyun ore concentration area. Among them, the Sachakou Pb-Zn deposit has reserves up to140 Mt, which has reached a large scale. However, the study on the genesis of deposits in this area has only just begun. This work studied the genesis ofthis Pb-Zn deposit in order to provide new ideas for the genesis of regional deposits and regional prospecting.
基金National Basic Research Program of China(No.2007CB411402)Cooperation Program of Institute of Geochemistry and Guizhou Geology and Minerals Bureau 102 Geology Group
文摘The Nage Cu-Pb polymetallic deposit is located in the transitional zone of the Yangtze craton and cathaysia,that is the southwest of Jiangnan orogenic belt. The mainly strata are Wentong formation of Mesoproterozoic Sibo group and the Jialu formation(Qbj) ,Wuye formation(Qbw) ,Fanzhao formation(Qbf) and Gongdong formation(Qbg) of the Neoproterozoic Qingbaikou System Xiajiang group.
基金Supported by Project of China Geological Survey(No.1212011085485).
文摘The Beiya porphyry-skarn gold-polymetallic deposit is one of the largest gold deposits in China and it also contains significant amounts of silver and base metals.The ore-bearing monzonitic granite porphyry occurs as a stock,of which the skarn type gold-copper-iron ore bodies are controlled by the contact zone between alkali-rich monzonitic granite porphyry and the limestone,and the gold-silver polymetallic mineralization is controlled by interlayer structure.Alteration and mineralization occur around the intrusion and exterior of monzonitic granite porphyry.Ore mineral formation sequence is as follows:skarn minerals→magnetite→pyrite→chalcopyrite/bornite+pyrite+gold→pyrite+galena+gold(silver).Petrographic studies of fluid inclusions indicate that the following types of inclusions exist in the pre-mineralization quartz-pyrite stage:gas-liquid two-phase inclusions(L-type),three-phase inclusions with daughter minerals(D-type)and gas-rich inclusions(V-type).The colorless transparent quartz in the main gold-chalcopyrite-pyrite stage mainly consists of L-type and V-type inclusions,whereas the inclusions in the late gold-silver-galena stage are mainly L-type.The evolution of ore-forming fluids shows a trend from high temperature,high salinity to medium-low temperature and low salinity.Medium-low density fluids play a dominant role in mineral component migration and transportation.Fluid cooling and boiling are the main mechanisms of gold-copper precipitation,while the involvement of atmospheric water and pH reduction are the main mechanisms of gold-silver polymetallic precipitation.The fluids in the quartz-pyrite stage before mineralization and the main gold-chalcopyrite-pyrite stage are dominated by magmatic water,while in the gold-silver-galena stage the fluids are dominated by atmospheric water.Isotope tracers show that S and Pb are mainly derived from monzonitic granite porphyry,not from limestone of the Beiya Formation.
基金supported by National Science Foundation of China (NSFC) project (40372049)innovation team of KMUST ore-forming dynamics and prediction of concealed deposits (2008)
文摘1 Introduction Southeast Yunnan is the convergent place of the Yangtze,Indochina blocks(Xu Wei,et al.2008).The Hongshiyan Pb-Zn-Cu polymetallic deposit is located in Wenshan Prefecture,Yunnan Province.It is a typical large sized VMS-type deposit discovered in recent years.The major ore minerals are sphalerite,galena,chalcopyrite ect.
基金the National Natural Science Foundation of China(Grant No.42162009)。
文摘Compared with the porphyry Cu-epithermal Au mineralization system,detailed studies on the porphyry Mo-epithermal Pb–Zn–Ag–Au mineralization are rare due to limited exposures.The Shipingchuan polymetallic deposit,located in the South China Mo Province(SCMP)represents a typical example containing both porphyry Mo and epithermal Pb–Zn–Ag mineralization.The Mo mineralization mainly occurs as molybdenite-quartz veins in veinlets or as disseminated molybdenite within the potassic,silicic,and sericitic syenogranite.The Pb–Zn–Ag mineralization is characterized by veinlet-type sphalerite–galena–pyrite–quartz–calcite vein within the volcanic rocks accompanied with silicifi cation and propylitization.Five molybdenite samples yield a Re–Os isochron age of 104.7±0.7 Ma that is consistent with the zircon age(107.5±2.1 Ma)of the ore-bearing syenogranite within errors.Together with previous reported Ar–Ar ages(106.6–121.8 Ma)of Pb–Zn–Ag related volcanic rocks,the Mo and Pb–Zn–Ag mineralization belong to a magmatic-hydrothermal event in the Early Cretaceous.Meanwhile,the total Re contents of molybednite range from 1.28 to 45.55 ppm,indicating the ore-forming materials were from a mixture between the mantle and crustal material.Moreover,previous sulfur isotopic values(3.7–4.3‰)of the pyrites from the porphyry Mo mineralization were consistent with the reported range of 4.0–6.1‰of the sphalerites from the Pb–Zn–Ag mineralization,implying that the sulfur of two-types of mineralization was derived from magma.The above-mentioned spatial,temporal,and isotopic lines of evidence suggest that the Mo and Pb–Zn–Ag mineralization of the Shipingchuan deposit was formed from the same metallogenic system.In consideration of regional tectonic evolution history,we propose that the porphyry Mo-epithermal Pb–Zn–Ag mineralization formed in an extensional tectonic setting caused by the continued rollback and the eventual slab break-off of the subducting PaleoPacifi c plate.
基金funded bythe Chinese Geological Survey Programme(Grant Nos.1212011120342,1212011121088)the Doctoral Scientific Research Foundation of Liaoning Provicen(Grant Nos.201601370)the Sixth Batch Production Technology Problem Foundation of Liaoning Technical University(Grant Nos.20160084T)
文摘The Berezitovoe deposit is a large-sized Au-Ag-Zn-Pb deposit in the east of the SelengaStanovoi superterrane, Russia. Au-Ag orebodies are hosted by tourmaline-garnet-quartz-muscovite metasomatic rocks; Zn-Pb orebodies are hosted by granodiorites, porphyritic granites and tourmalinegarnet-quartz-muscovite metasomatic rocks. These orebodies are surrounded by wall rocks dominated by the Tukuringra Complex granodiorites, porphyritic granites, and gneissic granodiorites. The alteration includes silicification and garnet, sericitization chloritization, carbonatization and kaollinization. LA-ICP-MS U-Pb zircon dating indicates that the gold mineralization can be divided into two stages in the Berezitovoe polymetallic gold deposit(at 363.5 ± 1.5 Ma, and133.4± 0.5).Hornblende-plagioclase gneisses of the Mogocha Group in the study area underwent Paleoproterozoic metamorphism(at 1870 ± 7.8 and 2400 ± 13 Ma), gneissic granodiorite of the Tukuringra Complex yields a late Paleozoic magmatic age(at 379.2 ± 1.1 Ma),and subalkaline porphyritic granitoid of the Amudzhikan Complex yield late Mesozoic magmatic ages(133-139 and 150-163 Ma). Granodiorites of the Tukuringra Complex in the study area have high concentrations of SiO_2(average of 60.9 wt%), are aluminum-oversaturated(average A/CNK of 1.49), are enriched in the large ion lithophile elements(e.g.,K, Rb, and Ba), U, Th, and Pb, are depleted in high field strength elements(e.g., Ta, Nb, and Ti), and have slightly negative Eu and no Ce anomalies in chondrite-normalized rare earth element diagrams.Fluid inclusions from quartz veins include three types: aqueous two-phase, CO2-bearing three-phase,and pure CO2. Aqueous two-phase inclusions homogenize at 167℃-249℃ and have salinities of 4.32%-9.47% NaCl equivalent, densities of 0.86-0.95 g/cm^3, and formed at depths of 0.52-0.94 km. In comparison, the CO2-bearing three-phase inclusions have homogenization temperatures of 265℃-346℃,salinities of 7.14%-11.57% NaCl equivalent, and total densities of 0.62-0.67 g/cm^3. The geochemical and zircon U-Pb data and the regional tectonic evolution of the study area, show that the Berezitovoe polymetallic gold deposit formed in an island arc or active continental margin setting, most probably related to late Paleozoic subduction of Okhotsk Ocean crust beneath the Siberian Plate.