The Dahongshan Group,situated at the southwestern margin of the Yangtze Block,represents a geological unit characterized by relatively high-grade metamorphism in the region.This paper investigates the garnet-biotite s...The Dahongshan Group,situated at the southwestern margin of the Yangtze Block,represents a geological unit characterized by relatively high-grade metamorphism in the region.This paper investigates the garnet-biotite schist from the Laochanghe Formation of the Dahongshan Group,employing an integrated approach that includes petrological analysis,phase equilibrium modeling,and zircon U-Pb dating.The schist is mainly composed of garnet,biotite,plagioclase,quartz,rutile,and ilmenite.Phase equilibrium modeling revealed the peak metamorphic conditions of 8-9 kbar and 635-675°C.By further integrating the prograde metamorphic profile of garnet and geothermobarometric results,a clockwise P-T metamorphic evolution path is constructed,which includes an increase in temperature and pressure during the prograde stage.LA-ICP-MS zircon U-Pb dating and zircon Ti thermometry constrains the post-peak metamorphic age of 831.2±7.2 Ma.Integrated with previously reported results,it is revealed that the southwestern margin of the Yangtze Block experienced a large-scale regional metamorphism during the Neoproterozoic(890-750 Ma),which is related to the collisional orogenic process.This may be associated with the late-stage assembly of the Rodinia supercontinent or with local compression and subduction processes during the breakup of the Rodinia supercontinent.展开更多
1 Introduction After the Dongchuan Orogenic movement(Hudsonian Orogeny,ca.1800 Ma±),the tectonic basement layer of the continental crust on the Yangtze massif could have been formed.And then tectonic-magmatic emp...1 Introduction After the Dongchuan Orogenic movement(Hudsonian Orogeny,ca.1800 Ma±),the tectonic basement layer of the continental crust on the Yangtze massif could have been formed.And then tectonic-magmatic emplacement展开更多
The Dahongshan Fe-Cu(-Au)deposit is a superlarge deposit in the Kangdian metallogenic belt,southwestern China,comprising approximately 458 Mt of Fe ores(40%Fe)and 1.35 Mt Cu.Two main types of Fe-Cu(-Au)mineralization ...The Dahongshan Fe-Cu(-Au)deposit is a superlarge deposit in the Kangdian metallogenic belt,southwestern China,comprising approximately 458 Mt of Fe ores(40%Fe)and 1.35 Mt Cu.Two main types of Fe-Cu(-Au)mineralization are present in the Dahongshan deposit:(1)early submarine volcanic exhalation and sedimentary mineralization characterized by strata-bound fine-grained magnetite and banded Fe-Cu sulfide(pyrite and chalcopyrite)hosted in the Na-rich metavolcanic rocks;(2)late hydrothermal(-vein)type mineralization characterized by Fe-Cu sulfide veins in the hosted strata or massive coarse-grained magnetite orebodies controlled by faults.While previous studies have focused primarily on the early submarine volcanic and sedimentary mineralization of the deposit,data related to late hydrothermal mineralization is lacking.In order to establish the metallogenic age and ore-forming material source of the late hydrothermal(-vein)type mineralization,this paper reports the Re-Os dating of molybdenite from the late hydrothermal vein Fe-Cu orebody and H,O,S,and Pb isotopic compositions of the hydrothermal quartz-sulfide veins.The primary aim of this study was to establish the metallogenic age and ore-forming material source of the hydrothermal type orebody.Results show that the molybdenite separated from quartz-sulfide veins has a Re-Os isochron age of 831±11 Ma,indicating that the Dahongshan Fe-Cu deposit experienced hydrothermal superimposed mineralization in Neoproterozoic.The molybdenite has a Re concentration of 99.7-382.4 ppm,indicating that the Re of the hydrothermal vein ores were primarily derived from the mantle.The δ^(34)S values of sulfides from the hydrothermal ores are 2‰-8‰ showing multi-peak tower distribution,suggesting that S in the ore-forming period was primarily derived from magma and partially from calcareous sedimentary rock.Furthermore,the abundance of radioactive Pb increased significantly from ore-bearing strata to layered and hydrothermal vein ores,which may be related to the later hydrothermal transformation.The composition of H and O isotopes within the hydrothermal quartz indicates that the ore-forming fluid is a mixture of magmatic water and a small quantity of water.These results further indicate that the late hydrothermal orebodies were formed by the Neoproterozoic magmatic hydrothermal event,which might be related to the breakup of the Rodinia supercontinent.Mantle derived magmatic hydrothermal fluid extracted ore-forming materials from the metavolcanic rocks of Dahongshan Group and formed the hydrothermal(-vein)type Fe-Cu orebodies by filling and metasomatism.展开更多
洋板块地质学是新一代中国区域地质志编撰专家组倡导的地质新理论(Ding Xiaozhong et al.,2020;李廷栋等,2019),其以俯冲增生杂岩带、蛇绿岩带等为研究对象,重点研究洋壳在洋中脊形成至海沟俯冲消亡的复杂洋陆转换过程(李廷栋等,2019)...洋板块地质学是新一代中国区域地质志编撰专家组倡导的地质新理论(Ding Xiaozhong et al.,2020;李廷栋等,2019),其以俯冲增生杂岩带、蛇绿岩带等为研究对象,重点研究洋壳在洋中脊形成至海沟俯冲消亡的复杂洋陆转换过程(李廷栋等,2019)。近年研究发现,湖北省发育中—新元古代庙湾蛇绿混杂岩、大洪山俯冲增生杂岩、吕王—高桥蛇绿混杂岩(图1).展开更多
Objective The Huashan group（composed of the lower Hongshansi Formation and the upper Liufangzui Formation）is an important Neoproterozoic stratigraphic unit along the northern margin of the Yangtze Block.Previous doc...Objective The Huashan group（composed of the lower Hongshansi Formation and the upper Liufangzui Formation）is an important Neoproterozoic stratigraphic unit along the northern margin of the Yangtze Block.Previous documents have focused on the geochronological and geochemical aspects of the Neoproterozoic sedimentary basin in the Dahongshan region.However.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42162012,42072094)the Key Laboratory of Sanjiang Metallogeny and Resource Exploration and Utilization,Ministry of Natural Resources(Project No.ZRZYBSJSYS2022001).
文摘The Dahongshan Group,situated at the southwestern margin of the Yangtze Block,represents a geological unit characterized by relatively high-grade metamorphism in the region.This paper investigates the garnet-biotite schist from the Laochanghe Formation of the Dahongshan Group,employing an integrated approach that includes petrological analysis,phase equilibrium modeling,and zircon U-Pb dating.The schist is mainly composed of garnet,biotite,plagioclase,quartz,rutile,and ilmenite.Phase equilibrium modeling revealed the peak metamorphic conditions of 8-9 kbar and 635-675°C.By further integrating the prograde metamorphic profile of garnet and geothermobarometric results,a clockwise P-T metamorphic evolution path is constructed,which includes an increase in temperature and pressure during the prograde stage.LA-ICP-MS zircon U-Pb dating and zircon Ti thermometry constrains the post-peak metamorphic age of 831.2±7.2 Ma.Integrated with previously reported results,it is revealed that the southwestern margin of the Yangtze Block experienced a large-scale regional metamorphism during the Neoproterozoic(890-750 Ma),which is related to the collisional orogenic process.This may be associated with the late-stage assembly of the Rodinia supercontinent or with local compression and subduction processes during the breakup of the Rodinia supercontinent.
基金financial support by The Researchon Occurrence State of Element and Tectonic Lithofacies Mapping Technique for the Iron -Oxide Copper Gold Deposits (2011EG115022, 2013EG115018)
文摘1 Introduction After the Dongchuan Orogenic movement(Hudsonian Orogeny,ca.1800 Ma±),the tectonic basement layer of the continental crust on the Yangtze massif could have been formed.And then tectonic-magmatic emplacement
基金supported by the NSFC Project(Grant Nos.42162012 and 42072094)the Open Research Project from the Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,MNR(Grant No.ZRZYBSJSYS2022001)。
文摘The Dahongshan Fe-Cu(-Au)deposit is a superlarge deposit in the Kangdian metallogenic belt,southwestern China,comprising approximately 458 Mt of Fe ores(40%Fe)and 1.35 Mt Cu.Two main types of Fe-Cu(-Au)mineralization are present in the Dahongshan deposit:(1)early submarine volcanic exhalation and sedimentary mineralization characterized by strata-bound fine-grained magnetite and banded Fe-Cu sulfide(pyrite and chalcopyrite)hosted in the Na-rich metavolcanic rocks;(2)late hydrothermal(-vein)type mineralization characterized by Fe-Cu sulfide veins in the hosted strata or massive coarse-grained magnetite orebodies controlled by faults.While previous studies have focused primarily on the early submarine volcanic and sedimentary mineralization of the deposit,data related to late hydrothermal mineralization is lacking.In order to establish the metallogenic age and ore-forming material source of the late hydrothermal(-vein)type mineralization,this paper reports the Re-Os dating of molybdenite from the late hydrothermal vein Fe-Cu orebody and H,O,S,and Pb isotopic compositions of the hydrothermal quartz-sulfide veins.The primary aim of this study was to establish the metallogenic age and ore-forming material source of the hydrothermal type orebody.Results show that the molybdenite separated from quartz-sulfide veins has a Re-Os isochron age of 831±11 Ma,indicating that the Dahongshan Fe-Cu deposit experienced hydrothermal superimposed mineralization in Neoproterozoic.The molybdenite has a Re concentration of 99.7-382.4 ppm,indicating that the Re of the hydrothermal vein ores were primarily derived from the mantle.The δ^(34)S values of sulfides from the hydrothermal ores are 2‰-8‰ showing multi-peak tower distribution,suggesting that S in the ore-forming period was primarily derived from magma and partially from calcareous sedimentary rock.Furthermore,the abundance of radioactive Pb increased significantly from ore-bearing strata to layered and hydrothermal vein ores,which may be related to the later hydrothermal transformation.The composition of H and O isotopes within the hydrothermal quartz indicates that the ore-forming fluid is a mixture of magmatic water and a small quantity of water.These results further indicate that the late hydrothermal orebodies were formed by the Neoproterozoic magmatic hydrothermal event,which might be related to the breakup of the Rodinia supercontinent.Mantle derived magmatic hydrothermal fluid extracted ore-forming materials from the metavolcanic rocks of Dahongshan Group and formed the hydrothermal(-vein)type Fe-Cu orebodies by filling and metasomatism.
文摘洋板块地质学是新一代中国区域地质志编撰专家组倡导的地质新理论(Ding Xiaozhong et al.,2020;李廷栋等,2019),其以俯冲增生杂岩带、蛇绿岩带等为研究对象,重点研究洋壳在洋中脊形成至海沟俯冲消亡的复杂洋陆转换过程(李廷栋等,2019)。近年研究发现,湖北省发育中—新元古代庙湾蛇绿混杂岩、大洪山俯冲增生杂岩、吕王—高桥蛇绿混杂岩(图1).
基金financially supported by the National Natural Science Foundation of China(grant No. 41402103,41502114 and 41372124)
文摘Objective The Huashan group（composed of the lower Hongshansi Formation and the upper Liufangzui Formation）is an important Neoproterozoic stratigraphic unit along the northern margin of the Yangtze Block.Previous documents have focused on the geochronological and geochemical aspects of the Neoproterozoic sedimentary basin in the Dahongshan region.However.
