The temperature,pH,f O 2 and Cl-activity have been considered to be significant physicochemical parameters which controlled sulphide mineralization.Especially,the change of pH is considered to play one of the key role...The temperature,pH,f O 2 and Cl-activity have been considered to be significant physicochemical parameters which controlled sulphide mineralization.Especially,the change of pH is considered to play one of the key roles in skarn deposit because of the involvement of marble.But few scholars have evaluated the impact of each parameter on mineralization.In this study,the authors have constructed thermodynamic model,calculated the important aqueous species activities in Baiyinnuo er deposit,and evaluated the influence of these parameters on the solubility of Pb and Zn.The results show that the log f O 2 decreased from-33.834 to-39.256,pH decreased from 4.0 to 3.7 and the Cl-activity increased from 0.25 to 0.30 in the main mineralization stage.The effect of f O 2 was readily ruled out because the reaction of Pb and Zn precipitation did not involve changes in the valence of the element.The decreased pH was impossible to be a mineralization factor,which was confirmed by metal solubility evaluation.The Cl-activity was also considered to be a negative factor.In fact,the dominant factor of mineralization was temperature,not the combination of various parameters as previously thought.Even in the skarn stage,the main factor to make the metal solubility>10%was also the high temperature.A significant increase in pH only occurred in the post-ore stage in response to the production of large amount of calcite.展开更多
1 Introduction The Huize Zn-Pb district is located in the tectonic composite position,became one of the important production areas of zinc,lead and germanium in China.In the Huize lead-zinc deposit,the interlayer faul...1 Introduction The Huize Zn-Pb district is located in the tectonic composite position,became one of the important production areas of zinc,lead and germanium in China.In the Huize lead-zinc deposit,the interlayer faults are most展开更多
The Baiyinnuo’er deposit in northern China is located in the south section of the Great Xing’an Range,and it is the largest skarn Zn–Pb deposit in the region.Skarn and Zn–Pb orebodies mainly occur between the diff...The Baiyinnuo’er deposit in northern China is located in the south section of the Great Xing’an Range,and it is the largest skarn Zn–Pb deposit in the region.Skarn and Zn–Pb orebodies mainly occur between the different units of the Permian Huanggangliang Formation,or within the contact zone between the intrusive rocks and the marble.Although Baiyinnuo’er has been well investigated previously,the timing of the Zn–Pb mineralization is still controversial,largely due to the lack of appropriate ore or alteration minerals that could be directly used for isotopic dating.In this study,we report the results of Rb–Sr isotopic analysis for sphalerite and pyrite samples from the Baiyinnuo’er orebodies,which yielded two isochron ages of 137.4±3.4 and 140.0±7.8 Ma,respectively,constraining the Zn–Pb mineralization time of the deposit as the Early Cretaceous.The data are also consistent with the age of the granitoids in the mining area,indicating a potential genetic relationship between the Early Cretaceous magmatism and mineralization.Many other intrusion-related hydrothermal deposits(including the two typical skarns,Huanggang and Haobugao)in the southern Great Xing’an Range also share similar mineralization ages(i.e.,140–130 Ma).Together,these data suggest an Early Cretaceous mineralization event in this region,and this largescale mineralization could be related to the regional tectonic regime transition from compression to extension as a result of the rollback of the subducted Paleo-Pacific plate.The initial87 Sr/86 Sr ratios of the sphalerite and pyrite samples are 0.70569 and 0.70616,respectively,implying that the ore-forming material could have a significant contribution from the mantle components.The current study shows that sulfide Rb–Sr dating could be used in deciphering the timing of skarn deposit formation.展开更多
The numerous non-sulfide zinc ore deposits were the historical basis for the development of zinc mining in Iran.They include the Mehdiabad,Irankouh and Angouran world-class deposits,as well as the Zarigan and Haft-har...The numerous non-sulfide zinc ore deposits were the historical basis for the development of zinc mining in Iran.They include the Mehdiabad,Irankouh and Angouran world-class deposits,as well as the Zarigan and Haft-har deposits.These deposits were formed by supergene oxidation of primary sulfide minerals during the complex interplay of tectonic uplift,karst development,changes in the level of the water table,and weathering.Zn(Pb)carbonates,Zn-hydrosilicates and associated hydrated phases directly replace the primary ore bodies or fill cavities along fractures related to uplift tectonics.Direct replacement of primary sulfides is accompanied by distal precipitation of zinc non-sulfide minerals in cavities or internal sediments filling.The mineralogy of the non-sulfide mineralization in all six deposits is generally complex and consists of smithsonite,hydrozincite,and hemimorphite as the main economic minerals,accompanied by iron and manganese oxy-hydroxides and residual clays.Commonly,non-sulfide minerals in these deposits consist of two types of ore:red zinc ore(RZO),rich in Zn,Fe,Pb-(As)and white zinc ore(WZO),typically with very high zinc grades but low concentrations of iron and lead.Typical minerals of the RZO are Fe-oxyhydroxides,goethite,hematite,hemimorphite,smithsonite and/or hydrozincite and cerussite.Common minerals of the WZO are smithsonite or hydrozincite and only minor amounts of Fe-oxyhydroxides and hemimorphite.展开更多
基金Self-determined Foundation of Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources(No.DBY-ZZ-18-12).
文摘The temperature,pH,f O 2 and Cl-activity have been considered to be significant physicochemical parameters which controlled sulphide mineralization.Especially,the change of pH is considered to play one of the key roles in skarn deposit because of the involvement of marble.But few scholars have evaluated the impact of each parameter on mineralization.In this study,the authors have constructed thermodynamic model,calculated the important aqueous species activities in Baiyinnuo er deposit,and evaluated the influence of these parameters on the solubility of Pb and Zn.The results show that the log f O 2 decreased from-33.834 to-39.256,pH decreased from 4.0 to 3.7 and the Cl-activity increased from 0.25 to 0.30 in the main mineralization stage.The effect of f O 2 was readily ruled out because the reaction of Pb and Zn precipitation did not involve changes in the valence of the element.The decreased pH was impossible to be a mineralization factor,which was confirmed by metal solubility evaluation.The Cl-activity was also considered to be a negative factor.In fact,the dominant factor of mineralization was temperature,not the combination of various parameters as previously thought.Even in the skarn stage,the main factor to make the metal solubility>10%was also the high temperature.A significant increase in pH only occurred in the post-ore stage in response to the production of large amount of calcite.
基金Funds for the Programs of the National Natural Science Foundation(Noes.41572060,U1133602)Projects of YM Lab(2011)Innovation Team of Yunnan province and KMUST(2008,2012)
文摘1 Introduction The Huize Zn-Pb district is located in the tectonic composite position,became one of the important production areas of zinc,lead and germanium in China.In the Huize lead-zinc deposit,the interlayer faults are most
基金the National Natural Science Foundation of China(41602083)the 111 Project of the Ministry of Science and Technology(BP0719021)the Fundamental Research Funds for the Central Universities(2652019045)。
文摘The Baiyinnuo’er deposit in northern China is located in the south section of the Great Xing’an Range,and it is the largest skarn Zn–Pb deposit in the region.Skarn and Zn–Pb orebodies mainly occur between the different units of the Permian Huanggangliang Formation,or within the contact zone between the intrusive rocks and the marble.Although Baiyinnuo’er has been well investigated previously,the timing of the Zn–Pb mineralization is still controversial,largely due to the lack of appropriate ore or alteration minerals that could be directly used for isotopic dating.In this study,we report the results of Rb–Sr isotopic analysis for sphalerite and pyrite samples from the Baiyinnuo’er orebodies,which yielded two isochron ages of 137.4±3.4 and 140.0±7.8 Ma,respectively,constraining the Zn–Pb mineralization time of the deposit as the Early Cretaceous.The data are also consistent with the age of the granitoids in the mining area,indicating a potential genetic relationship between the Early Cretaceous magmatism and mineralization.Many other intrusion-related hydrothermal deposits(including the two typical skarns,Huanggang and Haobugao)in the southern Great Xing’an Range also share similar mineralization ages(i.e.,140–130 Ma).Together,these data suggest an Early Cretaceous mineralization event in this region,and this largescale mineralization could be related to the regional tectonic regime transition from compression to extension as a result of the rollback of the subducted Paleo-Pacific plate.The initial87 Sr/86 Sr ratios of the sphalerite and pyrite samples are 0.70569 and 0.70616,respectively,implying that the ore-forming material could have a significant contribution from the mantle components.The current study shows that sulfide Rb–Sr dating could be used in deciphering the timing of skarn deposit formation.
文摘The numerous non-sulfide zinc ore deposits were the historical basis for the development of zinc mining in Iran.They include the Mehdiabad,Irankouh and Angouran world-class deposits,as well as the Zarigan and Haft-har deposits.These deposits were formed by supergene oxidation of primary sulfide minerals during the complex interplay of tectonic uplift,karst development,changes in the level of the water table,and weathering.Zn(Pb)carbonates,Zn-hydrosilicates and associated hydrated phases directly replace the primary ore bodies or fill cavities along fractures related to uplift tectonics.Direct replacement of primary sulfides is accompanied by distal precipitation of zinc non-sulfide minerals in cavities or internal sediments filling.The mineralogy of the non-sulfide mineralization in all six deposits is generally complex and consists of smithsonite,hydrozincite,and hemimorphite as the main economic minerals,accompanied by iron and manganese oxy-hydroxides and residual clays.Commonly,non-sulfide minerals in these deposits consist of two types of ore:red zinc ore(RZO),rich in Zn,Fe,Pb-(As)and white zinc ore(WZO),typically with very high zinc grades but low concentrations of iron and lead.Typical minerals of the RZO are Fe-oxyhydroxides,goethite,hematite,hemimorphite,smithsonite and/or hydrozincite and cerussite.Common minerals of the WZO are smithsonite or hydrozincite and only minor amounts of Fe-oxyhydroxides and hemimorphite.
