The REE patterns of primitive ore soutions in the Ailaoshan gold belt are char-acterized by significant enrichment of LREE, a weak negative anomaly of Eu and a ratherstrong negative anomaly of Ce. In conjunction with ...The REE patterns of primitive ore soutions in the Ailaoshan gold belt are char-acterized by significant enrichment of LREE, a weak negative anomaly of Eu and a ratherstrong negative anomaly of Ce. In conjunction with the tension crust in the region, the ore so-lutions are thought to be originated from a CO2-rich fluid as a result of mantle degassing.展开更多
Observations made in different superlarge\|large gold deposits in Ailaoshan gold metallogenic belts, Yunnan Province, China, on the eastern margin of the Qingzang (Himalayas—Karakoram—Tibet) were investigated. Geote...Observations made in different superlarge\|large gold deposits in Ailaoshan gold metallogenic belts, Yunnan Province, China, on the eastern margin of the Qingzang (Himalayas—Karakoram—Tibet) were investigated. Geotectonically, the study area is situated in the conjoint between the Tethys and Himalayas tectonic domain, characterized by very complex geological structure, with strongly influenced by the Himalayas in late development.1\ Regional geology and gold deposits\;Ailaoshan gold metallogenic belts is localized between Ailaoshan super lithospheric faults and Jiujia—Anding brittle\|ductile shear zone, with NNW\|trending about 250km long. To southward, Zhenyuan supergiant gold deposits, Mojiang large gold deposits, and Daping giant gold deposits hosted in low metamorphic volcanic\|sedimentary rocks (D—C). Ore types include gold\|bearing quartz veins, gold\|bearing altered rocks, and the mixing of the two types. Most of gold orebodies took their positions in the substructures of the brittle\|ductile shear zone.展开更多
The Chang＇an gold ore deposit in western Yunnan is located at the southern segment of the Ailaoshan metallogenic belt.The ore bodies are preserved in fractured Ordovician sedimentary clastic rocks.The gold-bearing mi...The Chang＇an gold ore deposit in western Yunnan is located at the southern segment of the Ailaoshan metallogenic belt.The ore bodies are preserved in fractured Ordovician sedimentary clastic rocks.The gold-bearing minerals occur dominantly in sulfide-quartz veins.Fluid inclusion analysis shows that the Chang＇an gold ore deposit is characterized by epithermal gold mineralization at temperatures between 200℃and 280℃at a shallow crustal level.The mineralizing fluids have intermediate to low salinity（6%-18%） and low densities（0.72-1.27 g/cm^3）.The ore minerals haveδ^（34）S in a range from -13‰to 3.57‰,concentrated from -2.06‰to 3.57‰with an average of 1.55‰.The ^（206）Pb/^（204）Pb,^（207）Pb/^（204）Pb and ^（208）Pb/^（204）Pb values are 18.9977-19.5748,15.7093-15.784,39.3814-40.2004 respectively.These isotope data suggest that the ore-forming elements were mainly derived from mixed crustal and mantle sources.The Chang＇an gold ore deposit and Tongchang Cu-Mo deposit are closely related to each other in their spatial distribution and age of formation.They have similar sources of mineralizing elements and identical ore-forming metal elements,and show a close relationship in physical and chemical conditions of mineralization.The two deposits constitute an epithermal-porphyry -skarn type Cu-Mo-Au mineralization system in the Tongchang-Chang＇an area,which is related to the Cenozoic high-K alkaline magmatism.展开更多
Zhenyuan gold deposit is the largest super large gold deposit in the Ailaoshan gold belt,but its precise mineralization age is still lack.Re-Os isotopic age of the auriferous pyrite from the Zhenyuan gold deposit was ...Zhenyuan gold deposit is the largest super large gold deposit in the Ailaoshan gold belt,but its precise mineralization age is still lack.Re-Os isotopic age of the auriferous pyrite from the Zhenyuan gold deposit was determined by using a high-resolution inductively coupled plasma mass spectrometry(HR-ICP-MS).The pyrite samples were decomposed in carius tubes,Os was separated by distillation and Re was extracted by acetone,respectively.The results show that the Re-Os isochron age is 229±38 Ma(MSWD=2.0,confidence level is 95%),with an initial 187 Os/188 Os value of 0.68±0.24 and a corresponding Os value of 442±91.The Re/Os ratios of the pyrite vary from 40.8 to 100.5.The data suggest that at least one important ore-forming event was occurred during Indosinian epoch,and the ore-forming materials probably derived from mixed sources of crustal and mantle,while the later dominated.The Ailaoshan composite orogen experienced complicated evolutional processes,including formation of Precambrian-Early Paleozoic basement,subduction and orogenesis of Late Paleozoic era,collisional orogenesis of Late Hercynian-Indosinain epoch,and extensional or striking orogenesis of Yanshainan-Cenozoic epoch.The polycycle tectonic evolution and magmatism in this area caused multi-stage and superposition metallization characteristics of the Zhenyuan gold deposit:the mineralization probably occur mainly during the Indosinian collisional orogeny,while the minor gold ores of altered granite-porphyry and altered lamprophyre may be formed in the late superposition metallization.展开更多
In recent years, with its application and development in the geological research fields,the ESR dating technique has become a new method to study the age of gold deposits.Some researchers at home and abroad have used ...In recent years, with its application and development in the geological research fields,the ESR dating technique has become a new method to study the age of gold deposits.Some researchers at home and abroad have used this method to study some younger uranium deposits, and got ore-forming ages similar to those acquired from U-Pb dating method. In this note, we chose some quartz paragenous with gold to study the age of three typical gold deposits in Ailaoshan gold belt by ESR method. Finally, we will discuss the genesis of the deposits.展开更多
After determining that sulfur is the main mineralizer of ore forming fluid of Ailaoshan gold mineralization belt in west Yunnan Province of China, the S, He and Ar isotope compositions and geological events related to...After determining that sulfur is the main mineralizer of ore forming fluid of Ailaoshan gold mineralization belt in west Yunnan Province of China, the S, He and Ar isotope compositions and geological events related to gold mineralization are studied. It is revealed that the ore forming fluid of the belt is a mixture of high temperature S rich deep seated fluid and low temperature S depleted meteoric groundwater. That the gold mineralization occurred in early Himalayan period resulted dominantly from the mantle degassing which was associated with the crust extension at that time. The forming and evolving process of ore forming fluid can be determined as: S rich deep seated fluid ascended and added to S depleted meteogenic fluid cycling in shallow fracture systems of the belt in early Himalayan period →the S depleted meteogenic fluid converted to the mixing fluid containing sufficient S→gold in surrounding rocks was extracted by the mixing fluid, and then precipitated at a suitable place to form the gold deposits.展开更多
IN the previous studies of hydrothermal deposits much attention was paid to their material sources ratherthan the mechanisms of dynamic association of ore-forming fluids. In recent years many studies haveshown that or...IN the previous studies of hydrothermal deposits much attention was paid to their material sources ratherthan the mechanisms of dynamic association of ore-forming fluids. In recent years many studies haveshown that ore-forming elements were transferred into ore-forming solutions after some suitable mineralizerwas incorporated into hydrothermal solutions. Therefore, the time at which the mineralizer is incorporated into hydrothermal solutions could, to a great extent, reflect the time of ore deposition. In the dynamic study of the origin of ore deposits on a trial basis the author took the Ailaoshan gold belt in YunnanProvince as an example and carried out investigations into the sources of mineralizers (the anion coordinates of stable complexes of gold in hydrothermal solutions) in ore-forming hydrothermal solutions and theconstraints of relevant geological events on gold mineralization.展开更多
文摘The REE patterns of primitive ore soutions in the Ailaoshan gold belt are char-acterized by significant enrichment of LREE, a weak negative anomaly of Eu and a ratherstrong negative anomaly of Ce. In conjunction with the tension crust in the region, the ore so-lutions are thought to be originated from a CO2-rich fluid as a result of mantle degassing.
文摘Observations made in different superlarge\|large gold deposits in Ailaoshan gold metallogenic belts, Yunnan Province, China, on the eastern margin of the Qingzang (Himalayas—Karakoram—Tibet) were investigated. Geotectonically, the study area is situated in the conjoint between the Tethys and Himalayas tectonic domain, characterized by very complex geological structure, with strongly influenced by the Himalayas in late development.1\ Regional geology and gold deposits\;Ailaoshan gold metallogenic belts is localized between Ailaoshan super lithospheric faults and Jiujia—Anding brittle\|ductile shear zone, with NNW\|trending about 250km long. To southward, Zhenyuan supergiant gold deposits, Mojiang large gold deposits, and Daping giant gold deposits hosted in low metamorphic volcanic\|sedimentary rocks (D—C). Ore types include gold\|bearing quartz veins, gold\|bearing altered rocks, and the mixing of the two types. Most of gold orebodies took their positions in the substructures of the brittle\|ductile shear zone.
基金supported by the National Key Basic Research and Development(973)Project (2009CB421001)China Geological Survey (1212010661311)+1 种基金Ministry of Land and Resources (200811008)the Ministry of Education,Project 111 (B07011)
文摘The Chang＇an gold ore deposit in western Yunnan is located at the southern segment of the Ailaoshan metallogenic belt.The ore bodies are preserved in fractured Ordovician sedimentary clastic rocks.The gold-bearing minerals occur dominantly in sulfide-quartz veins.Fluid inclusion analysis shows that the Chang＇an gold ore deposit is characterized by epithermal gold mineralization at temperatures between 200℃and 280℃at a shallow crustal level.The mineralizing fluids have intermediate to low salinity（6%-18%） and low densities（0.72-1.27 g/cm^3）.The ore minerals haveδ^（34）S in a range from -13‰to 3.57‰,concentrated from -2.06‰to 3.57‰with an average of 1.55‰.The ^（206）Pb/^（204）Pb,^（207）Pb/^（204）Pb and ^（208）Pb/^（204）Pb values are 18.9977-19.5748,15.7093-15.784,39.3814-40.2004 respectively.These isotope data suggest that the ore-forming elements were mainly derived from mixed crustal and mantle sources.The Chang＇an gold ore deposit and Tongchang Cu-Mo deposit are closely related to each other in their spatial distribution and age of formation.They have similar sources of mineralizing elements and identical ore-forming metal elements,and show a close relationship in physical and chemical conditions of mineralization.The two deposits constitute an epithermal-porphyry -skarn type Cu-Mo-Au mineralization system in the Tongchang-Chang＇an area,which is related to the Cenozoic high-K alkaline magmatism.
基金supported by the National Natural Science Foundation of China(40830425,40673045 and 40373027)the National Basic Research Program of China(2009CB421006 and 2002CB412610)+1 种基金Research Fund for the Doctoral Program of Higher Education of China(200805580031)the Project Supported by Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2011)
文摘Zhenyuan gold deposit is the largest super large gold deposit in the Ailaoshan gold belt,but its precise mineralization age is still lack.Re-Os isotopic age of the auriferous pyrite from the Zhenyuan gold deposit was determined by using a high-resolution inductively coupled plasma mass spectrometry(HR-ICP-MS).The pyrite samples were decomposed in carius tubes,Os was separated by distillation and Re was extracted by acetone,respectively.The results show that the Re-Os isochron age is 229±38 Ma(MSWD=2.0,confidence level is 95%),with an initial 187 Os/188 Os value of 0.68±0.24 and a corresponding Os value of 442±91.The Re/Os ratios of the pyrite vary from 40.8 to 100.5.The data suggest that at least one important ore-forming event was occurred during Indosinian epoch,and the ore-forming materials probably derived from mixed sources of crustal and mantle,while the later dominated.The Ailaoshan composite orogen experienced complicated evolutional processes,including formation of Precambrian-Early Paleozoic basement,subduction and orogenesis of Late Paleozoic era,collisional orogenesis of Late Hercynian-Indosinain epoch,and extensional or striking orogenesis of Yanshainan-Cenozoic epoch.The polycycle tectonic evolution and magmatism in this area caused multi-stage and superposition metallization characteristics of the Zhenyuan gold deposit:the mineralization probably occur mainly during the Indosinian collisional orogeny,while the minor gold ores of altered granite-porphyry and altered lamprophyre may be formed in the late superposition metallization.
文摘In recent years, with its application and development in the geological research fields,the ESR dating technique has become a new method to study the age of gold deposits.Some researchers at home and abroad have used this method to study some younger uranium deposits, and got ore-forming ages similar to those acquired from U-Pb dating method. In this note, we chose some quartz paragenous with gold to study the age of three typical gold deposits in Ailaoshan gold belt by ESR method. Finally, we will discuss the genesis of the deposits.
文摘After determining that sulfur is the main mineralizer of ore forming fluid of Ailaoshan gold mineralization belt in west Yunnan Province of China, the S, He and Ar isotope compositions and geological events related to gold mineralization are studied. It is revealed that the ore forming fluid of the belt is a mixture of high temperature S rich deep seated fluid and low temperature S depleted meteoric groundwater. That the gold mineralization occurred in early Himalayan period resulted dominantly from the mantle degassing which was associated with the crust extension at that time. The forming and evolving process of ore forming fluid can be determined as: S rich deep seated fluid ascended and added to S depleted meteogenic fluid cycling in shallow fracture systems of the belt in early Himalayan period →the S depleted meteogenic fluid converted to the mixing fluid containing sufficient S→gold in surrounding rocks was extracted by the mixing fluid, and then precipitated at a suitable place to form the gold deposits.
文摘IN the previous studies of hydrothermal deposits much attention was paid to their material sources ratherthan the mechanisms of dynamic association of ore-forming fluids. In recent years many studies haveshown that ore-forming elements were transferred into ore-forming solutions after some suitable mineralizerwas incorporated into hydrothermal solutions. Therefore, the time at which the mineralizer is incorporated into hydrothermal solutions could, to a great extent, reflect the time of ore deposition. In the dynamic study of the origin of ore deposits on a trial basis the author took the Ailaoshan gold belt in YunnanProvince as an example and carried out investigations into the sources of mineralizers (the anion coordinates of stable complexes of gold in hydrothermal solutions) in ore-forming hydrothermal solutions and theconstraints of relevant geological events on gold mineralization.
