The Liziyuan gold deposit, situated on the south side of the Shangdan suture zone, West Qinling Orogen, occurs in metamorphic volcanic rocks(greenschist facies) of the early Paleozoic Liziyuan Group and in Indosinian ...The Liziyuan gold deposit, situated on the south side of the Shangdan suture zone, West Qinling Orogen, occurs in metamorphic volcanic rocks(greenschist facies) of the early Paleozoic Liziyuan Group and in Indosinian Tianzishan monzogranite. Orebodies in the Liziyuan gold field are controlled by the ductile-brittle shear zone, and by thrusting nappe faults related to the Indosinian orogeny. In detail, this paper analyzed the geological characteristics of the Liziyuan gold field, and the Pb isotopes of the Lziyuan host rocks, granitoids(Tianzishan monzogranite and Jiancaowan syenite porphyry), sulfides, and auriferous quartz veins by multiple-collector inductively coupled plasma mass spectrometry(MC-ICPMS). In addition, previous data on the sulfur, hydrogen, and oxygen isotopes were employed to discuss the possible sources of the ore-forming fluids and materials, and to further understand the tectonic setting of the Liziyuan gold deposit. The sulfides and their host rocks(Lziyuan Group), Tianzishan monzogranite and Jiancaowan syenite porphyry, and auriferous quartz veins have similar Pb isotopic compositions.Zartman’s plumbotectonic model diagram shows that most of the data for the deposit fall near the orogenic Pb evolutionary curve or within the area between the orogenic and mantle Pb evolutionary curves. In the△β-△γ diagram, which genetically classifies the lead isotopes, most of the data fall within the range of the subduction-zone lead mixed with upper crust and mantle. This indicates that a complex source of the ore lead formed in the orogenic environment. The δ34S values of the sulfides range from 3.90 to 8.50‰(average6.80‰), with a pronounced mode at 5.00‰-8.00‰. These values are consistent with that of orogenic gold deposits worldwide, indicating that the sulfur sourced mainly from reduced metamorphic fluids. The isotopic hydrogen and oxygen compositions support a predominantly metamorphic origin of the oreforming fluids, with possible mixing of minor magmatic fluids, but the late stage was dominated by meteoric water. The characteristics of the Liziyuan gold deposit formed in the Indosinian orogenic environment of the Qinling Orogen are consistent with those of orogenic gold deposits found worldwide.展开更多
This paper aims at exploring the tectonic characteristics of the South China Continent （SCC） and extracting the universal tec- tonic rules from these characteristics,to help enrich the plate tectonic theory and bett...This paper aims at exploring the tectonic characteristics of the South China Continent （SCC） and extracting the universal tec- tonic rules from these characteristics,to help enrich the plate tectonic theory and better understand the continental dynamic system. For this purpose, here we conduct a multi-disciplinary investigation and combine it with the previous studies to reas- sess the tectonics and evolution of SCC and propose that the tectonic framework of the continent comprises two blocks, three types of tectonic units, four deformation systems, and four evolutionary stages with distinctive mechanism and tectonic characteris- tics since the Neoproterozoic. The four evolutionary stages are： （1） The amalgamation and break-up of the Neoproterozoic plates, typically the intracontinental rifting. （2） The early Paleozoic and Mesozoic intracontinental orogeny confined by plate tectonics, forming two composite tectonic domains. （3） The parallel operation of the Yangtze cratonization and intracontinental orogeny, and multi-phase reactivation of the Yangtze craton. （4） The association and differentiation evolution of plate tectonics and intraconti- nental tectonics, and the dynamic characteristics under the Meso-Cenozoic modem global plate tectonic regime.展开更多
基金jointly provided by the National Natural Science Foundation of China (Grant Nos. 41421002, 41730426, 41272092, and 41030423)MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest UniversityNorthwest University Graduate Innovation and Creativity Fund (YZZ17190)
文摘The Liziyuan gold deposit, situated on the south side of the Shangdan suture zone, West Qinling Orogen, occurs in metamorphic volcanic rocks(greenschist facies) of the early Paleozoic Liziyuan Group and in Indosinian Tianzishan monzogranite. Orebodies in the Liziyuan gold field are controlled by the ductile-brittle shear zone, and by thrusting nappe faults related to the Indosinian orogeny. In detail, this paper analyzed the geological characteristics of the Liziyuan gold field, and the Pb isotopes of the Lziyuan host rocks, granitoids(Tianzishan monzogranite and Jiancaowan syenite porphyry), sulfides, and auriferous quartz veins by multiple-collector inductively coupled plasma mass spectrometry(MC-ICPMS). In addition, previous data on the sulfur, hydrogen, and oxygen isotopes were employed to discuss the possible sources of the ore-forming fluids and materials, and to further understand the tectonic setting of the Liziyuan gold deposit. The sulfides and their host rocks(Lziyuan Group), Tianzishan monzogranite and Jiancaowan syenite porphyry, and auriferous quartz veins have similar Pb isotopic compositions.Zartman’s plumbotectonic model diagram shows that most of the data for the deposit fall near the orogenic Pb evolutionary curve or within the area between the orogenic and mantle Pb evolutionary curves. In the△β-△γ diagram, which genetically classifies the lead isotopes, most of the data fall within the range of the subduction-zone lead mixed with upper crust and mantle. This indicates that a complex source of the ore lead formed in the orogenic environment. The δ34S values of the sulfides range from 3.90 to 8.50‰(average6.80‰), with a pronounced mode at 5.00‰-8.00‰. These values are consistent with that of orogenic gold deposits worldwide, indicating that the sulfur sourced mainly from reduced metamorphic fluids. The isotopic hydrogen and oxygen compositions support a predominantly metamorphic origin of the oreforming fluids, with possible mixing of minor magmatic fluids, but the late stage was dominated by meteoric water. The characteristics of the Liziyuan gold deposit formed in the Indosinian orogenic environment of the Qinling Orogen are consistent with those of orogenic gold deposits found worldwide.
基金supported by the special grant of Ministry of Science and Technology of the People’s Republic of China for State Key Laboratory of Continental Dynamics,Northwest University,the key research project of Sinopec Group(Grant No.YPH08012)the National Natural Science Foundation of China(Grant Nos.41190072,41190073,41190074,41190070)
文摘This paper aims at exploring the tectonic characteristics of the South China Continent （SCC） and extracting the universal tec- tonic rules from these characteristics,to help enrich the plate tectonic theory and better understand the continental dynamic system. For this purpose, here we conduct a multi-disciplinary investigation and combine it with the previous studies to reas- sess the tectonics and evolution of SCC and propose that the tectonic framework of the continent comprises two blocks, three types of tectonic units, four deformation systems, and four evolutionary stages with distinctive mechanism and tectonic characteris- tics since the Neoproterozoic. The four evolutionary stages are： （1） The amalgamation and break-up of the Neoproterozoic plates, typically the intracontinental rifting. （2） The early Paleozoic and Mesozoic intracontinental orogeny confined by plate tectonics, forming two composite tectonic domains. （3） The parallel operation of the Yangtze cratonization and intracontinental orogeny, and multi-phase reactivation of the Yangtze craton. （4） The association and differentiation evolution of plate tectonics and intraconti- nental tectonics, and the dynamic characteristics under the Meso-Cenozoic modem global plate tectonic regime.
