The giant Huize Zn-Pb ore field in Yunnan Province, southwestern China, comprises the Qilinchang and Kuangshanchang deposits. The deposits are large in scale (more than 5 Mt of Zn and Pb) and high in grade (average gr...The giant Huize Zn-Pb ore field in Yunnan Province, southwestern China, comprises the Qilinchang and Kuangshanchang deposits. The deposits are large in scale (more than 5 Mt of Zn and Pb) and high in grade (average grade of total Zn and Pb is 30%). Reported in this paper are the results of Rb-Sr isotopic dating of sphalerite from this ore field. Two precise ages (223.5±3.9 Ma and 226±6.4 Ma) have been obtained from two isochrons. These two ages are close to the reported ages of native copper mineralizations related to the Emeishan flood basalts in this region, which are 226 Ma to 228 Ma. Previous studies showed that the magnitude of uplift resultant from the Emeishan flood basalts is greater than 1000 m, indicating that the Kuangshanchang and Qilinchang deposits were formed during the same geological event and originated by fluid migration during uplifting resultant from the Emeishan flood basalts.展开更多
On the basis of detailed geological studies of the Wulong gold deposit, three metallogenic stages can be identified. With quartz fluid inclusions as an object of study, the authors investigated phase characteristics, ...On the basis of detailed geological studies of the Wulong gold deposit, three metallogenic stages can be identified. With quartz fluid inclusions as an object of study, the authors investigated phase characteristics, compositional variations, temperature and pressure changes, fluid evolution, Pb isotope tracing and Rb-Sr isotopic dating of fluid inclusions entrapped in the above three metallogenic stages. The results show that Na+ is decreased obviously with metallogenic evolution, while K+ and other cations and gas compositions (H2, CO, CH4 and CO2) are increased slightly, and that the temperature and salinity vary in a pulsating manner along with the metallogenic evolution. Inverse calculation of hydrogen and oxygen isotopes indicate that at the first metallogenic stage the fluids were magmatic water, at the second stage they were dominated by magmatic water with a minor amount of meteoric water involved, and at the third stage, i.e., the final stage of metallogenesis, the fluids were composed completely of meteoric water. Its Pb isotopic composition implicates that the ore lead has some affinities with the lead in the Sanguliu granite, but the linear array of the ore-lead isotopic data reflects a mixing source of two end members. It can be deduced that the ore-forming materials and magma were both derived mainly from the same magma source region at depths. The Rb-Sr isotopic ages of the fluid inclusions are 112.2±3.2 Ma, indicating that the Wulong gold deposit was formed during the Yanshanian period.展开更多
Zircon U-Pb dating by the LA-ICP-MS method was applied to determining the ages of different units of the Guposhan granite complex, among which the East Guposhan unit is 160.8±1.6 Ma, the West Guposhan unit is 165...Zircon U-Pb dating by the LA-ICP-MS method was applied to determining the ages of different units of the Guposhan granite complex, among which the East Guposhan unit is 160.8±1.6 Ma, the West Guposhan unit is 165.0±1.9 Ma, and the Lisong unit is 163.0±1.3 Ma in age. Much similarity in ages of the three units has thus proved that the whole Guposhan granite complex was formed in the same period of time. They were the products of large-scale granitic magmatism through crust-remelting in the first stage of the Middle Yanshanian in South China. However, the three units have differences both in petrology and in geochemistry. Besides the differences in major, trace and rare-earth elements, they are distinct in their Rb-Sr and Sm-Nd isotopic compositions. The East Guposhan unit and Lisong unit and its enclaves have a similar (87Sr/86Sr)i value of 0.7064 with an average of εNd(t)=-3.03, indicating that more mantle material was evolved in the magma derivation; whereas the West Guposhan unit has a higher (87Sr/86Sr)i value of 0.7173 but a lower εNd(t) value of -5.00, and is characterized by strong negative Eu anomalies and higher Rb/Sr ratios, suggesting that its source materials were composed of relatively old crust components and new mantle-derived components. In addition, an inherited zircon grain in the East Guposhan unit (GP-1) yielded a 206Pb/238U age of 806.4 Ma, which is similar to the ages of the Jiulin cordierite granite in northern Jiangxi and of the Yinqiao migmatic granite in Guangxi in the HZH granite zone. All this may provide new evidence for Late Proterozoic magmatism in the HZH granite zone.展开更多
The Jinshan gold deposit is located in the Northeast Jiangxi province,South China,which related to the ductile shear zone.It contains two ore types,i.e.the alteration-type ore and the goldbearing quartz vein ore.Rb-Sr...The Jinshan gold deposit is located in the Northeast Jiangxi province,South China,which related to the ductile shear zone.It contains two ore types,i.e.the alteration-type ore and the goldbearing quartz vein ore.Rb-Sr age dating is applied to both gold-bearing pyrite in the alteration-type ore and fluid inclusion in the gold-bearing quartz vein to make clear the time of the gold mineralization of the Jinshan deposit.Analytical results of this study yielded that the age of the alteration-type ore bodies is about 838±110Ma,with an initial 87Sr/86Sr value of 0.7045±0.0020.However,the age of the gold-bearing quartz vein-type ore is about 379±49Ma,and the initial 87Sr/86Sr is 0.7138±0.0011.Based on the age data from this work and many previous studies,the authors consider that the Jinshan gold deposit is a product of multi-staged mineralization,which may include the Jinninian,Caledonian,Hercynian,and Yanshanian Periods.Among them,the Jinninian Period and the Hercynian Period might be the two most important ore-forming periods for Jinshan deposit.The Jinninian Period is the main stage for the formation of alteration-type ore bodies,while the Hercynian Period is the major time for ore bodies of gold-bearing quartz vein type.The initial values of the 87Sr/86Sr from this study,as well as the previous isotope and trace element studies,indicate that the ore-forming materials mainly derived from the metamorphic wall rocks,and the ore-forming fluids mainly originated from the deep metamorphic water.展开更多
The Hongdonggou Pb-Zn polymetallic ore deposit, located in the southwestern part of the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore mineralization in Henan Province, China, is an important part of the East Qinling metall...The Hongdonggou Pb-Zn polymetallic ore deposit, located in the southwestern part of the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore mineralization in Henan Province, China, is an important part of the East Qinling metallogenic belt. The orebodies in the deposit, which are vein, bedded and lenticular, are mainly hosted in the syenite porphyry, and formed within the carbonate and clastic rocks of the Yuku and Qiumugou formations partially. The genesis of the deposit has previously been argued to be of hydrothermal-vein type or of skarn-hydrothermal type. In this study, we report the results of Rb-Sr isotopic dating based on sphalerites from the main orebody of the Hongdonggou Pb-Zn polymetallic ore deposit, which yield an isochron age of 135.7 ± 3.2 Ma, constraining the timing of mineralization as early Cretaceous. The age is close to those reported for the Pb-Zn deposits in the Luanchuan ore belt. The （87Sr/86Sr）i values of the sphalerites （0.71127± 0.00010） are lower than that of terrigenous silicates （0.720） and higher than the mantle （0.707）, suggesting that the metallogenic components were mainly derived through crust-mantle mixing. Combining the results from this study with those from previous work, we propose that the Hongdonggou Pb-Zn polymetallic ore deposit is a hydrothermal-vein deposit associated with the early Cretaceous tectonothermal event, and the mineralization is controlled by NW- and near EW-trending faults in the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore concentration belt.展开更多
This paper discusses the Rb-Sr geochemical behaviour of illites in the sedimentary process, and points out that illites of the lmd and lm types could reach Sr-isotopic equilibrium with its environmental medium during ...This paper discusses the Rb-Sr geochemical behaviour of illites in the sedimentary process, and points out that illites of the lmd and lm types could reach Sr-isotopic equilibrium with its environmental medium during the sedimentary process and initial stage of diagenesis, and illite grains of different sizes have various Rb contents. A new dating method for sedimentary rocks----a dating model of illite grain Rb-Sr isochron----is established, in consideration of the geochemical process of Sr-isotopic homogenization and differentiation in the course of their formation and evolution. In addition, the paper concerns the application of the dating model to the Precambrian unmetamorphosed sedimentary rocks in western Henan Province, which gives satisfactory results coincident with the geological facts.展开更多
As a part of a giant trending fault system in the Asian continent and one where a strong zone of left strikeslip fault is present,the Altyn Orogenic belt(AOB)has become an important focus for research.Magmatic rocks a...As a part of a giant trending fault system in the Asian continent and one where a strong zone of left strikeslip fault is present,the Altyn Orogenic belt(AOB)has become an important focus for research.Magmatic rocks are widely distributed across the AOB.However,many investigations have focused primarily on Paleozoic igneous rocks;discussion of Mesozoic related igneous activity is often ignored.Here we present the result of studies of representative diorite and granite rocks outcropping in the AOB,within the Xinjiang Uygur Autonomous Region,South Altyn,China.We present new zircon LA-ICP-MS U-Pb age,geochemical,and Sr-Nd-Pb-Hf isotopic data for these sample suites,identifying them as typical igneous rocks formed between 238±1.5 and 238.8±1.1 Ma.The rocks that we studied fall into the alkaline series,also enriched in light rare earth elements(LREE),some large ion lithophile elements(LILE;e.g.,Rb,Ba,Sr,and K),Pb,Th and U,and depleted in heavy rare earth elements(HREE),Nb,Ta,Hf,and Ti.The granite and diorite have high initial 87Sr/86Sr ratios(0.7062-0.7114),negativeεNd(t)values(-8.8 to-11.3),εHf(t)values(-8.7 to-18.7),and relatively constant Pb isotopic ratios((206-Pb/204Pb)i=6.74-17.884,(207Pb/204Pb)i=15.51-15.58,and(208Pb/204Pb)i=35.36-38.04),respectively.This suggests that the magmas parental to these rocks were generated from the partial melting of the ancient crust.The parental magmas to these rocks experienced a degree of fractionation of plagioclase,K-feldspar,and hornblende,possibly during rapid magma ascent.Based on these studies,we propose a reasonable model for the origin of the investigated rocks from the Xinjiang Uygur Autonomous Region of South Altyn,which involves crustal thickening,lithospheric extension,and asthenosphere upwelling,that induced crustal melting.展开更多
Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at ...Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet.Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization.LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1±0.2 Ma and 19.0±0.2 Ma for greisenized monzogranite and fresh monzogranite,respectively.The monzogranites are characterized as strongly peraluminous,with high contents of SiO2,Al2O3,K2O and Na2O as well as a high differentiation index.They are enriched in light rare earth and large ion lithophile elements with significant negative Eu anomalies and depleted high fieldstrength elements.Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites,derived from remelting of crustal materials in a post-collisional setting.The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution.The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 40573036, 40502011)
文摘The giant Huize Zn-Pb ore field in Yunnan Province, southwestern China, comprises the Qilinchang and Kuangshanchang deposits. The deposits are large in scale (more than 5 Mt of Zn and Pb) and high in grade (average grade of total Zn and Pb is 30%). Reported in this paper are the results of Rb-Sr isotopic dating of sphalerite from this ore field. Two precise ages (223.5±3.9 Ma and 226±6.4 Ma) have been obtained from two isochrons. These two ages are close to the reported ages of native copper mineralizations related to the Emeishan flood basalts in this region, which are 226 Ma to 228 Ma. Previous studies showed that the magnitude of uplift resultant from the Emeishan flood basalts is greater than 1000 m, indicating that the Kuangshanchang and Qilinchang deposits were formed during the same geological event and originated by fluid migration during uplifting resultant from the Emeishan flood basalts.
基金This research project was supported by the Outstanding Young Scientists Foundation(Grant No 49625304)the Ministry of Sciences and Technology of China(Grant No 95-pre-39).
文摘On the basis of detailed geological studies of the Wulong gold deposit, three metallogenic stages can be identified. With quartz fluid inclusions as an object of study, the authors investigated phase characteristics, compositional variations, temperature and pressure changes, fluid evolution, Pb isotope tracing and Rb-Sr isotopic dating of fluid inclusions entrapped in the above three metallogenic stages. The results show that Na+ is decreased obviously with metallogenic evolution, while K+ and other cations and gas compositions (H2, CO, CH4 and CO2) are increased slightly, and that the temperature and salinity vary in a pulsating manner along with the metallogenic evolution. Inverse calculation of hydrogen and oxygen isotopes indicate that at the first metallogenic stage the fluids were magmatic water, at the second stage they were dominated by magmatic water with a minor amount of meteoric water involved, and at the third stage, i.e., the final stage of metallogenesis, the fluids were composed completely of meteoric water. Its Pb isotopic composition implicates that the ore lead has some affinities with the lead in the Sanguliu granite, but the linear array of the ore-lead isotopic data reflects a mixing source of two end members. It can be deduced that the ore-forming materials and magma were both derived mainly from the same magma source region at depths. The Rb-Sr isotopic ages of the fluid inclusions are 112.2±3.2 Ma, indicating that the Wulong gold deposit was formed during the Yanshanian period.
基金Granted jointly by the State Key Fundamental Research Project （Grant No. 1999CB403209） the National Natural Science Foundation of China （Grant No. 40132010）.
文摘Zircon U-Pb dating by the LA-ICP-MS method was applied to determining the ages of different units of the Guposhan granite complex, among which the East Guposhan unit is 160.8±1.6 Ma, the West Guposhan unit is 165.0±1.9 Ma, and the Lisong unit is 163.0±1.3 Ma in age. Much similarity in ages of the three units has thus proved that the whole Guposhan granite complex was formed in the same period of time. They were the products of large-scale granitic magmatism through crust-remelting in the first stage of the Middle Yanshanian in South China. However, the three units have differences both in petrology and in geochemistry. Besides the differences in major, trace and rare-earth elements, they are distinct in their Rb-Sr and Sm-Nd isotopic compositions. The East Guposhan unit and Lisong unit and its enclaves have a similar (87Sr/86Sr)i value of 0.7064 with an average of εNd(t)=-3.03, indicating that more mantle material was evolved in the magma derivation; whereas the West Guposhan unit has a higher (87Sr/86Sr)i value of 0.7173 but a lower εNd(t) value of -5.00, and is characterized by strong negative Eu anomalies and higher Rb/Sr ratios, suggesting that its source materials were composed of relatively old crust components and new mantle-derived components. In addition, an inherited zircon grain in the East Guposhan unit (GP-1) yielded a 206Pb/238U age of 806.4 Ma, which is similar to the ages of the Jiulin cordierite granite in northern Jiangxi and of the Yinqiao migmatic granite in Guangxi in the HZH granite zone. All this may provide new evidence for Late Proterozoic magmatism in the HZH granite zone.
基金supported by the National Natural Science Foundation of China (No. 41202083, 40373025)the Research Award Fund for Outstanding Middle-aged and Young Scientist of Shandong Province (BS2013HZ024)
文摘The Jinshan gold deposit is located in the Northeast Jiangxi province,South China,which related to the ductile shear zone.It contains two ore types,i.e.the alteration-type ore and the goldbearing quartz vein ore.Rb-Sr age dating is applied to both gold-bearing pyrite in the alteration-type ore and fluid inclusion in the gold-bearing quartz vein to make clear the time of the gold mineralization of the Jinshan deposit.Analytical results of this study yielded that the age of the alteration-type ore bodies is about 838±110Ma,with an initial 87Sr/86Sr value of 0.7045±0.0020.However,the age of the gold-bearing quartz vein-type ore is about 379±49Ma,and the initial 87Sr/86Sr is 0.7138±0.0011.Based on the age data from this work and many previous studies,the authors consider that the Jinshan gold deposit is a product of multi-staged mineralization,which may include the Jinninian,Caledonian,Hercynian,and Yanshanian Periods.Among them,the Jinninian Period and the Hercynian Period might be the two most important ore-forming periods for Jinshan deposit.The Jinninian Period is the main stage for the formation of alteration-type ore bodies,while the Hercynian Period is the major time for ore bodies of gold-bearing quartz vein type.The initial values of the 87Sr/86Sr from this study,as well as the previous isotope and trace element studies,indicate that the ore-forming materials mainly derived from the metamorphic wall rocks,and the ore-forming fluids mainly originated from the deep metamorphic water.
基金supported by the National Science and Technology Support Project of the 12th"Five-Year Plan"(Grant No.2011BAB04B06)the Fundamental Research Funds for the Central Universities of China University of Geosciences,Beijing(Grant No.2-9-2012-143)the National Natural Science Foundation of China(Grant No.41572318)
文摘The Hongdonggou Pb-Zn polymetallic ore deposit, located in the southwestern part of the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore mineralization in Henan Province, China, is an important part of the East Qinling metallogenic belt. The orebodies in the deposit, which are vein, bedded and lenticular, are mainly hosted in the syenite porphyry, and formed within the carbonate and clastic rocks of the Yuku and Qiumugou formations partially. The genesis of the deposit has previously been argued to be of hydrothermal-vein type or of skarn-hydrothermal type. In this study, we report the results of Rb-Sr isotopic dating based on sphalerites from the main orebody of the Hongdonggou Pb-Zn polymetallic ore deposit, which yield an isochron age of 135.7 ± 3.2 Ma, constraining the timing of mineralization as early Cretaceous. The age is close to those reported for the Pb-Zn deposits in the Luanchuan ore belt. The （87Sr/86Sr）i values of the sphalerites （0.71127± 0.00010） are lower than that of terrigenous silicates （0.720） and higher than the mantle （0.707）, suggesting that the metallogenic components were mainly derived through crust-mantle mixing. Combining the results from this study with those from previous work, we propose that the Hongdonggou Pb-Zn polymetallic ore deposit is a hydrothermal-vein deposit associated with the early Cretaceous tectonothermal event, and the mineralization is controlled by NW- and near EW-trending faults in the Luanchuan Mo-W-Pb-Zn-Ag polymetallic ore concentration belt.
基金This research was financially supported by the Academia Sinica Foundation
文摘This paper discusses the Rb-Sr geochemical behaviour of illites in the sedimentary process, and points out that illites of the lmd and lm types could reach Sr-isotopic equilibrium with its environmental medium during the sedimentary process and initial stage of diagenesis, and illite grains of different sizes have various Rb contents. A new dating method for sedimentary rocks----a dating model of illite grain Rb-Sr isochron----is established, in consideration of the geochemical process of Sr-isotopic homogenization and differentiation in the course of their formation and evolution. In addition, the paper concerns the application of the dating model to the Precambrian unmetamorphosed sedimentary rocks in western Henan Province, which gives satisfactory results coincident with the geological facts.
基金supported by the National Natural Science Foundation of China(Grant No.:41573022)。
文摘As a part of a giant trending fault system in the Asian continent and one where a strong zone of left strikeslip fault is present,the Altyn Orogenic belt(AOB)has become an important focus for research.Magmatic rocks are widely distributed across the AOB.However,many investigations have focused primarily on Paleozoic igneous rocks;discussion of Mesozoic related igneous activity is often ignored.Here we present the result of studies of representative diorite and granite rocks outcropping in the AOB,within the Xinjiang Uygur Autonomous Region,South Altyn,China.We present new zircon LA-ICP-MS U-Pb age,geochemical,and Sr-Nd-Pb-Hf isotopic data for these sample suites,identifying them as typical igneous rocks formed between 238±1.5 and 238.8±1.1 Ma.The rocks that we studied fall into the alkaline series,also enriched in light rare earth elements(LREE),some large ion lithophile elements(LILE;e.g.,Rb,Ba,Sr,and K),Pb,Th and U,and depleted in heavy rare earth elements(HREE),Nb,Ta,Hf,and Ti.The granite and diorite have high initial 87Sr/86Sr ratios(0.7062-0.7114),negativeεNd(t)values(-8.8 to-11.3),εHf(t)values(-8.7 to-18.7),and relatively constant Pb isotopic ratios((206-Pb/204Pb)i=6.74-17.884,(207Pb/204Pb)i=15.51-15.58,and(208Pb/204Pb)i=35.36-38.04),respectively.This suggests that the magmas parental to these rocks were generated from the partial melting of the ancient crust.The parental magmas to these rocks experienced a degree of fractionation of plagioclase,K-feldspar,and hornblende,possibly during rapid magma ascent.Based on these studies,we propose a reasonable model for the origin of the investigated rocks from the Xinjiang Uygur Autonomous Region of South Altyn,which involves crustal thickening,lithospheric extension,and asthenosphere upwelling,that induced crustal melting.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC2905001)the National Natural Science Foundation of China(Grant Nos.42272093,42230813)+1 种基金the Basic Research Fund of the Chinese Academy of Geological Sciences(Grant Nos.JKYZD202316,KK2116)the China Scholarship Council project and the Geological Survey project(Grant No.DD20230054).
文摘Rubidium(Rb)deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites.This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet.Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization.LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1±0.2 Ma and 19.0±0.2 Ma for greisenized monzogranite and fresh monzogranite,respectively.The monzogranites are characterized as strongly peraluminous,with high contents of SiO2,Al2O3,K2O and Na2O as well as a high differentiation index.They are enriched in light rare earth and large ion lithophile elements with significant negative Eu anomalies and depleted high fieldstrength elements.Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites,derived from remelting of crustal materials in a post-collisional setting.The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution.The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.
