China is rich in tin resources,and contains many types of tin deposits.Among the tin deposit types,the cassiterite-sulfide type,skarn type and quartz vein type occupy a large proportion of tin resources and reserves.F...China is rich in tin resources,and contains many types of tin deposits.Among the tin deposit types,the cassiterite-sulfide type,skarn type and quartz vein type occupy a large proportion of tin resources and reserves.From the aspect of exploitation and utilization,the most important types are cassiterite-sulfide type and quartz vein type.The cassiterite-sulfide type tin deposits are mainly located in Northern Guangxi and Eastern Yunnan,skarn type deposits are mainly distributed in the ore-concentration areas of South Hunan in Middle Nanling,and the quartz vein type tin deposits are mainly distributed in South China,such as Western Fujian,Middle Jiangxi,Northern Guangzhou and Southern Hunan.The most important metallogenic epoch for tin deposits is the Mesozoic era.The metallogenic geotectonic background is mainly continental environments after orogeny process,with strong tectonic changes,interlaced deep fracture and frequent magmatism.And the most distinctive feature is the well developed Mesozoic granites,which have a close relationship with tin mineralization.Based on the detailed study of the data from 873 tin deposits in China,this paper summarized the metallogenic regularity of tin deposits,classified 20 important metallogenic series of tin or tin-associated deposits,and inferred that the cassiterite-sulfide type,skarn type,quartz vein type and greisen type are the main prediction types of tin resources.Forty-four tin-mineralization belts were divided,among which,19 belts are the most important.In addition,a series of maps about tin metallogenic belts and tin metallogenic regularity were compiled,aiming to provide theoretical basis for potential estimation and prediction of tin mineral resources.展开更多
Objective The Yangbin porphyry tin deposit in Taishun County of Zhejiang Province is one of the few porphyry-type tin deposits in South China, which is located in the middle portion of the Mesozoic volcanic active bel...Objective The Yangbin porphyry tin deposit in Taishun County of Zhejiang Province is one of the few porphyry-type tin deposits in South China, which is located in the middle portion of the Mesozoic volcanic active belt on the southeastern coast of China. The Yangbin granite porphyry is closely related to the tin mineralization in this region. Based on petrologic and Sr-Nd-Pb isotopic展开更多
Through studies on the element geochemistry, alteration of country rocks, ore-forming fluids and isotopegeochemistry of the Arno tin deposit in the metamorphic rocks of the Upper Proterozoic Ximeng Group, theauthors c...Through studies on the element geochemistry, alteration of country rocks, ore-forming fluids and isotopegeochemistry of the Arno tin deposit in the metamorphic rocks of the Upper Proterozoic Ximeng Group, theauthors consider that the concentration of the B-F-Li-Rb-Cs-Sn association is related to acidic magmatism inthe study area. The Fe-Mg-Li tourmaline in the ore is the replaced product of the country rocks byhypothermal fluid. The δ^(18)O values of mineral separates are +2.01- +13.16‰ and their δ^(34)S values, +2.6-+7.2‰. The ore-forming materials were derived from hydrothermal fluid of granitic magma. For themineralization, the temperature is 450°-350℃, the pressure, 450-1000×10~5 Pa, and the age, Himalayan(21.5 Ma). According to the geochemical characteristics, a minerogenic model is established: the deposit is ahypothermal cassiterite-quartz vein type tin deposit controlled by the hidden Himalayan granites.展开更多
No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical anal...No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical analysis to study the types of association of main ore-forming elements at different temperatures and pressures and their distribution in the deposit. On that basis combined with the structural analysis of the deposit, the recto-geochemical features of No.6 East tin deposit have been revealed and the direction and channel of migration of the ore solutions in faults and the deposit have been deduced. This research can appropriately elucidate the control of faults on the migration of ore solutions and the sites where ore solutions are dispersed and accumulated, thus providing the theoretical basis for the prediction of hydrothermal deposits in question.展开更多
In this paper the authors present the REE concentrations and Sr and Nd isotopic compositions of fluorites from the Bailashui tin deposit of the Furong ore field,southern Hunan Province. The results showed that the tot...In this paper the authors present the REE concentrations and Sr and Nd isotopic compositions of fluorites from the Bailashui tin deposit of the Furong ore field,southern Hunan Province. The results showed that the total amount of REE in fluorites is usually low,ranging from 0.705 to 8.785 μg/g with the chondrite-normalized REE dis-tribution patterns similar to those of the Qitianling granites in the study area,characterized by LREE-enrichment patterns with pronounced negative Eu anomalies. The fluorites vary in Sr isotopic composition within the range of 0.7083-0.7091,the values are lower than those of the granites and higher than those of the host carbonate rocks in this area. The εNd(t) values of fluorites vary between -9.4 and +10.3,revealing that both the crust-and mantle-source materials were involved in the ore-forming hydrothermal fluids. Combined with previous studies on this ore deposit,the Bailashui tin deposit is temporally and spatially closely related with granitic magmatism in this area. The hydro-thermal fluorites are the product of fluid/rock interactions between granitic magmatic hydrothermal fluid and marine carbonate rocks. The REE and F in the ore-forming fluid were derived from the granites,whereas Sr in the ore-forming fluid came mainly from the granitic magmatic hydrothermal fluid and marine carbonate rocks,although variations in Sr isotopic composition cannot be explained by a simple mixture of these two end-members. Evidence demonstrated that the ore-forming fluids are of crustal-mantle mixing origin,but that the fluids were probably in-completely homogenized and this may be caused by inhomogeneous mixing of the fluids of different sources.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
Xitian tin-polymetallic deposit, located in the eastern Hunan Province, SE China, hosts quartz vein and skarn in the contact zone between carbonate and two stages granites. Critical geodynamic questions for South Chin...Xitian tin-polymetallic deposit, located in the eastern Hunan Province, SE China, hosts quartz vein and skarn in the contact zone between carbonate and two stages granites. Critical geodynamic questions for South China are whether different types of mineralization form in the same time and how the magmatism–tectonic system controls the ore-forming process. Based on the distribution of the orebodies, six cassiterite samples from different types of mineralization are collected for dating. In-situ LA-MCICP-MS U–Pb isotopic data yielded concordia low intercept ages between 154 and 157 Ma, indicating that different types of mineralization belong to the same magmatism–mineralization system. Coupled with the study of the kinematic indicators, it suggests that the structural control of the wall rocks constrain the types of mineralization. These results provide further evidence of a close temporal link between the structure and the tin-polymetallic mineralization in Xitian deposit. Considering the structure in the district, granite dome plays an important role in the ore-forming process. The age and structural signatures in Xitian deposit are the response to the subduction of Pacific Plate.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
No. 22 ore of Dafulou deposit was systematically analyzed for sulfur isotopes. The results show that the δ34S values of sulfide minerals, ranging from 0.154 to +0.218% and with an average value of +0.114 1%, are most...No. 22 ore of Dafulou deposit was systematically analyzed for sulfur isotopes. The results show that the δ34S values of sulfide minerals, ranging from 0.154 to +0.218% and with an average value of +0.114 1%, are mostly positive and characterized by rich sulfur(S) content. This suggests that the sulfur of the Dafulou ore deposit is derived from magma and relates to the Longxianggai concealed granite, which points to the important role of magma during mineralization and implyies the product of the active continental margin. By comparison between the Dafulou and the Kengma tin deposit, significant differences exist in the sulfur isotope composition. In the Kengma deposit, the sulfur isotope composition is characterized by the high negative value, which is different from the Dafulou tin-polymetallic deposit. The difference of the enrichment and fractionation of the sulfur isotope is the synthesized result of the metallogenic conditions. It also has the difference in the metallogenic environment and metallogenic characteristics of the deposit in the same ore belt.展开更多
This paper introduces the petrological, mineralogical and geochemical fea. tures of the rocks hosting the Sareshik tin deposit—an independent tin deposit related to Hercynian A-type granites discovered in China in 19...This paper introduces the petrological, mineralogical and geochemical fea. tures of the rocks hosting the Sareshik tin deposit—an independent tin deposit related to Hercynian A-type granites discovered in China in 1987. A comparison with the features of A-type granites at home and abroad indicates that some of their petrological features are more typical than those of famous A-type granites of Nigeria. The geological features of the tin deposit are salient and notably different from those of some famous tin deposits in China, so the deposit may represent China’s deposits associated with anorogenic granites. This tin deposit was formed in the Hercynian Stage. This type of tin deposit was for the first time discovered in China and is also rare in the world. It is a new type of tin deposit in China.展开更多
By means of multivariance analysis and finite element on the basis of the analysis of generation andevolution of structural systems and structural system of syn-metallogenesis in the orefield,the authorsmade a researc...By means of multivariance analysis and finite element on the basis of the analysis of generation andevolution of structural systems and structural system of syn-metallogenesis in the orefield,the authorsmade a research into the interrelation between tecto-geochemistry and structural stress field,revealedthe mechanism of metallogenesis by magma and ore-forming fluids driven under dynamic forces,andproposed a tecto-geochemistry model for the formation of the ore deposits,so as to suggest a basis oftheory for the prognoses of location and magnitude of hidden deposits.展开更多
The TiN films were synthesized with an alternate process of depositing titanium from a E-gun evaporation source and 40 keV N^+ bombarding onto the target.It is shown from the composi- tion analysis and structure inves...The TiN films were synthesized with an alternate process of depositing titanium from a E-gun evaporation source and 40 keV N^+ bombarding onto the target.It is shown from the composi- tion analysis and structure investigations using RBS,AES,TEM,XPS and X-ray diffraction spectrum that the formed fihns are mainly composed of TiN phase with grain size of 30—40 nm and without preferred orientation,the nitrogen content in the film is much less than that in case without N^+ bombarding,and an intermixed region about 40 nm thick exists between the film and the substrate.The films exhibt high microhardness and low friction. ZHOU Jiankun,Ion Beam Laboratory,Shanghai Institute of Metallurgy,Academia Sinica, Shanghai 200050,China展开更多
A new method for preparation of hard TiN films has been developed by using electron beam evaporation-deposition of Ti and bombardment with 40 keV Xe^+ ion beam in a N_2 gas environment.The synthesized TiN films were s...A new method for preparation of hard TiN films has been developed by using electron beam evaporation-deposition of Ti and bombardment with 40 keV Xe^+ ion beam in a N_2 gas environment.The synthesized TiN films were superior to PVD and CVD ones in respects of improved adhesion to substrate and low preparing temperature.They exhibited good wear resistance and high hardness up to 2200 kg/mm^2.Some industrial applications have been reported.展开更多
Titanium nitride ceramic thin films on 317L stainless steel(SS317L) substrate were deposited by Ion Beam Assisted Deposition (IBAD). The composition of the TiN films were investigated by Auger electron spectroscopy(AE...Titanium nitride ceramic thin films on 317L stainless steel(SS317L) substrate were deposited by Ion Beam Assisted Deposition (IBAD). The composition of the TiN films were investigated by Auger electron spectroscopy(AES), while the preferential orientation of the deposited film and phase composition were determined by X-ray diffraction(XRD). Adhesion was measured through Micro Scratch Tester(MST), and the corrosion resistance was evaluated by the electrochemical corrosion experiments in Hamk’s simulated human plasma. Specially, the biocompatibility of SS317L and TiN thin films were studied with fibroblast and marrow cell cultures in vitro. The results show that TiN thin films deposited on SS317L by means of IBAD can make remarkable changes on the structure and properties of the surface. At 37℃ Hank’s simulated plasma, free corrosion potential (E corr ) and breakthrough potential of pitting corrosion (E b) were both improved by coating TiN films . The culture results show that ion beam assisted TiN coatings exhibit a higher degree of cytocompatibility than that of SS317L and the cells grow better on those proper rough surfaces.展开更多
基金supported by the National Natural Science Foundation(grant No.41202025,41302058)Funds on basic researches for central public welfare academic institutes(grant No.K1325 and YK1401)the China Geological Survey Project(Nos.1212011220369, 1212010633903,12120114039601 and 12120114019401)
文摘China is rich in tin resources,and contains many types of tin deposits.Among the tin deposit types,the cassiterite-sulfide type,skarn type and quartz vein type occupy a large proportion of tin resources and reserves.From the aspect of exploitation and utilization,the most important types are cassiterite-sulfide type and quartz vein type.The cassiterite-sulfide type tin deposits are mainly located in Northern Guangxi and Eastern Yunnan,skarn type deposits are mainly distributed in the ore-concentration areas of South Hunan in Middle Nanling,and the quartz vein type tin deposits are mainly distributed in South China,such as Western Fujian,Middle Jiangxi,Northern Guangzhou and Southern Hunan.The most important metallogenic epoch for tin deposits is the Mesozoic era.The metallogenic geotectonic background is mainly continental environments after orogeny process,with strong tectonic changes,interlaced deep fracture and frequent magmatism.And the most distinctive feature is the well developed Mesozoic granites,which have a close relationship with tin mineralization.Based on the detailed study of the data from 873 tin deposits in China,this paper summarized the metallogenic regularity of tin deposits,classified 20 important metallogenic series of tin or tin-associated deposits,and inferred that the cassiterite-sulfide type,skarn type,quartz vein type and greisen type are the main prediction types of tin resources.Forty-four tin-mineralization belts were divided,among which,19 belts are the most important.In addition,a series of maps about tin metallogenic belts and tin metallogenic regularity were compiled,aiming to provide theoretical basis for potential estimation and prediction of tin mineral resources.
基金supported by the National Key R&D Program of China (grant No. 2016YFC0600405)the National Natural Science Foundation of China (grants No. 41672079 and 41372085)Strategic Priority Research Program (B) of the Chinese Academy of Sciences (grant No. XDB1803206)
文摘Objective The Yangbin porphyry tin deposit in Taishun County of Zhejiang Province is one of the few porphyry-type tin deposits in South China, which is located in the middle portion of the Mesozoic volcanic active belt on the southeastern coast of China. The Yangbin granite porphyry is closely related to the tin mineralization in this region. Based on petrologic and Sr-Nd-Pb isotopic
文摘Through studies on the element geochemistry, alteration of country rocks, ore-forming fluids and isotopegeochemistry of the Arno tin deposit in the metamorphic rocks of the Upper Proterozoic Ximeng Group, theauthors consider that the concentration of the B-F-Li-Rb-Cs-Sn association is related to acidic magmatism inthe study area. The Fe-Mg-Li tourmaline in the ore is the replaced product of the country rocks byhypothermal fluid. The δ^(18)O values of mineral separates are +2.01- +13.16‰ and their δ^(34)S values, +2.6-+7.2‰. The ore-forming materials were derived from hydrothermal fluid of granitic magma. For themineralization, the temperature is 450°-350℃, the pressure, 450-1000×10~5 Pa, and the age, Himalayan(21.5 Ma). According to the geochemical characteristics, a minerogenic model is established: the deposit is ahypothermal cassiterite-quartz vein type tin deposit controlled by the hidden Himalayan granites.
文摘No. 6 East tin deposit in the Songshujiao orefield, Gejiu, is characterized by one-stage hydrothermal activity and monotonous country rocks. The authors selected this deposit and used the multivariate statistical analysis to study the types of association of main ore-forming elements at different temperatures and pressures and their distribution in the deposit. On that basis combined with the structural analysis of the deposit, the recto-geochemical features of No.6 East tin deposit have been revealed and the direction and channel of migration of the ore solutions in faults and the deposit have been deduced. This research can appropriately elucidate the control of faults on the migration of ore solutions and the sites where ore solutions are dispersed and accumulated, thus providing the theoretical basis for the prediction of hydrothermal deposits in question.
基金financially supported jointly by the Key Program of Knowledge Innovation from the Chinese Academy of Sciences (Grant KZCX-3-SW-125)the National Natural Science Foundation of China (Grant Nos.40472053 and 40673021)Special Foundation on Fundamental Scientific Research as Operating Expenses among Commonweal Scientific Research In-stitutes at National Level (Grant K2007-1-12)
文摘In this paper the authors present the REE concentrations and Sr and Nd isotopic compositions of fluorites from the Bailashui tin deposit of the Furong ore field,southern Hunan Province. The results showed that the total amount of REE in fluorites is usually low,ranging from 0.705 to 8.785 μg/g with the chondrite-normalized REE dis-tribution patterns similar to those of the Qitianling granites in the study area,characterized by LREE-enrichment patterns with pronounced negative Eu anomalies. The fluorites vary in Sr isotopic composition within the range of 0.7083-0.7091,the values are lower than those of the granites and higher than those of the host carbonate rocks in this area. The εNd(t) values of fluorites vary between -9.4 and +10.3,revealing that both the crust-and mantle-source materials were involved in the ore-forming hydrothermal fluids. Combined with previous studies on this ore deposit,the Bailashui tin deposit is temporally and spatially closely related with granitic magmatism in this area. The hydro-thermal fluorites are the product of fluid/rock interactions between granitic magmatic hydrothermal fluid and marine carbonate rocks. The REE and F in the ore-forming fluid were derived from the granites,whereas Sr in the ore-forming fluid came mainly from the granitic magmatic hydrothermal fluid and marine carbonate rocks,although variations in Sr isotopic composition cannot be explained by a simple mixture of these two end-members. Evidence demonstrated that the ore-forming fluids are of crustal-mantle mixing origin,but that the fluids were probably in-completely homogenized and this may be caused by inhomogeneous mixing of the fluids of different sources.
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financially supported by the Public Welfare Project of the Ministry of land and Resources of China (201211024-04)National Key R&D Program of China (2016YFC0600401)+1 种基金National Science Foundation of China (NSFC Grant 41273046)Research Cooperation between Institute and University of Chinese Academy of Sciences Grant (Y552012Y00)
文摘Xitian tin-polymetallic deposit, located in the eastern Hunan Province, SE China, hosts quartz vein and skarn in the contact zone between carbonate and two stages granites. Critical geodynamic questions for South China are whether different types of mineralization form in the same time and how the magmatism–tectonic system controls the ore-forming process. Based on the distribution of the orebodies, six cassiterite samples from different types of mineralization are collected for dating. In-situ LA-MCICP-MS U–Pb isotopic data yielded concordia low intercept ages between 154 and 157 Ma, indicating that different types of mineralization belong to the same magmatism–mineralization system. Coupled with the study of the kinematic indicators, it suggests that the structural control of the wall rocks constrain the types of mineralization. These results provide further evidence of a close temporal link between the structure and the tin-polymetallic mineralization in Xitian deposit. Considering the structure in the district, granite dome plays an important role in the ore-forming process. The age and structural signatures in Xitian deposit are the response to the subduction of Pacific Plate.
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Project(41202051) supported by the National Natural Science Foundation of ChinaProject(2012M521721) supported by China Postdoctoral Science FoundationProject(CSUZC2013021) supported by Valuable Equipment Open Sharing Fund of Central South University,China
文摘No. 22 ore of Dafulou deposit was systematically analyzed for sulfur isotopes. The results show that the δ34S values of sulfide minerals, ranging from 0.154 to +0.218% and with an average value of +0.114 1%, are mostly positive and characterized by rich sulfur(S) content. This suggests that the sulfur of the Dafulou ore deposit is derived from magma and relates to the Longxianggai concealed granite, which points to the important role of magma during mineralization and implyies the product of the active continental margin. By comparison between the Dafulou and the Kengma tin deposit, significant differences exist in the sulfur isotope composition. In the Kengma deposit, the sulfur isotope composition is characterized by the high negative value, which is different from the Dafulou tin-polymetallic deposit. The difference of the enrichment and fractionation of the sulfur isotope is the synthesized result of the metallogenic conditions. It also has the difference in the metallogenic environment and metallogenic characteristics of the deposit in the same ore belt.
文摘This paper introduces the petrological, mineralogical and geochemical fea. tures of the rocks hosting the Sareshik tin deposit—an independent tin deposit related to Hercynian A-type granites discovered in China in 1987. A comparison with the features of A-type granites at home and abroad indicates that some of their petrological features are more typical than those of famous A-type granites of Nigeria. The geological features of the tin deposit are salient and notably different from those of some famous tin deposits in China, so the deposit may represent China’s deposits associated with anorogenic granites. This tin deposit was formed in the Hercynian Stage. This type of tin deposit was for the first time discovered in China and is also rare in the world. It is a new type of tin deposit in China.
文摘By means of multivariance analysis and finite element on the basis of the analysis of generation andevolution of structural systems and structural system of syn-metallogenesis in the orefield,the authorsmade a research into the interrelation between tecto-geochemistry and structural stress field,revealedthe mechanism of metallogenesis by magma and ore-forming fluids driven under dynamic forces,andproposed a tecto-geochemistry model for the formation of the ore deposits,so as to suggest a basis oftheory for the prognoses of location and magnitude of hidden deposits.
文摘The TiN films were synthesized with an alternate process of depositing titanium from a E-gun evaporation source and 40 keV N^+ bombarding onto the target.It is shown from the composi- tion analysis and structure investigations using RBS,AES,TEM,XPS and X-ray diffraction spectrum that the formed fihns are mainly composed of TiN phase with grain size of 30—40 nm and without preferred orientation,the nitrogen content in the film is much less than that in case without N^+ bombarding,and an intermixed region about 40 nm thick exists between the film and the substrate.The films exhibt high microhardness and low friction. ZHOU Jiankun,Ion Beam Laboratory,Shanghai Institute of Metallurgy,Academia Sinica, Shanghai 200050,China
文摘A new method for preparation of hard TiN films has been developed by using electron beam evaporation-deposition of Ti and bombardment with 40 keV Xe^+ ion beam in a N_2 gas environment.The synthesized TiN films were superior to PVD and CVD ones in respects of improved adhesion to substrate and low preparing temperature.They exhibited good wear resistance and high hardness up to 2200 kg/mm^2.Some industrial applications have been reported.
基金This project is supported by Tianjin Nature Fundation (contract No:0 2 36 136 11)
文摘Titanium nitride ceramic thin films on 317L stainless steel(SS317L) substrate were deposited by Ion Beam Assisted Deposition (IBAD). The composition of the TiN films were investigated by Auger electron spectroscopy(AES), while the preferential orientation of the deposited film and phase composition were determined by X-ray diffraction(XRD). Adhesion was measured through Micro Scratch Tester(MST), and the corrosion resistance was evaluated by the electrochemical corrosion experiments in Hamk’s simulated human plasma. Specially, the biocompatibility of SS317L and TiN thin films were studied with fibroblast and marrow cell cultures in vitro. The results show that TiN thin films deposited on SS317L by means of IBAD can make remarkable changes on the structure and properties of the surface. At 37℃ Hank’s simulated plasma, free corrosion potential (E corr ) and breakthrough potential of pitting corrosion (E b) were both improved by coating TiN films . The culture results show that ion beam assisted TiN coatings exhibit a higher degree of cytocompatibility than that of SS317L and the cells grow better on those proper rough surfaces.