The Huanggang intrusive complex in northern Tongbai area was formed in Early Paleozoic. It mainly consists of ultra basic, basic, intermediate and acid rocks, dominated by intermediate and basic rocks. The complex be...The Huanggang intrusive complex in northern Tongbai area was formed in Early Paleozoic. It mainly consists of ultra basic, basic, intermediate and acid rocks, dominated by intermediate and basic rocks. The complex belongs to calc alkaline series. Geochemical characteristics of major and trace elements show that the complex was derived from the fractional crystallization of co source magma. It is suggested that the complex was formed in island arc tectonic environment and was closely related to the northward subduction of the Erlangping back arc basin. Thus, the subduction of the back arc basin can induce the island arc type magmatism similar to the one formed in the setting of ocean plate subduction.展开更多
The Duolong area is the most important part of the Western Bangong-Nujiang Suture Zone porphyry Cu（Au） metallogenic belt, in Tibet, China. Here new detailed data are presented from LAICP-MS zircon U-Pb, whole-rock g...The Duolong area is the most important part of the Western Bangong-Nujiang Suture Zone porphyry Cu（Au） metallogenic belt, in Tibet, China. Here new detailed data are presented from LAICP-MS zircon U-Pb, whole-rock geochemical, and in-situ zircon Hf isotope analyses for igneous rocks in the large Naruo deposit（2.51 Mt of Cu and 82 t of Au） which is located ~2 km NE of the Duolong（Duobuza and Bolong） super-large gold-rich porphyry copper deposit. We integrated our results with previous research of other porphyry deposits in the Duolong area and have identified the timing, geodynamic setting, and petrogenesis of the mineralization-associated magmatic events. Based on the measurements, the Duolong area porphyry Cu（Au） deposit formations are associated with Early Cretaceous intermediate-felsic magmatism, which is consistent with U-Pb zircon ages of 120 Ma. All the main intrusive rocks in the ore-concentrated area have similar lithogeochemical characteristics; they show a relative enrichment in both light rare earth elements（LREEs） and large-ion lithophile elements（LILEs： Rb, Ba, K, etc.） and relative depletion in both heavy rare earth elements（HREEs） and high field strength elements（HFSEs： Nb, Ta, Zr, Hf, etc.）. Moreover, the granite porphyry shows positive εHf（t） values between 1.38–7.37 suggesting that magmas were potentially derived from the partial melting of a depleted mantle wedge that had been metasomatized by subducted slab-derived fluids or melts. This paper points out that the formation of the porphyry-epithermal Cu（Au） deposit in the Duolong area was dominated by northward subduction of the Bangongco Tethys Plate beneath the Qiangtang block in the Early Cretaceous（124–114 Ma）, when the subducted oceanic crust reached 50–70 km underground and generated different degrees of phase transformation, which lead to a melt produced by dehydration of amphibole minerals, a metasomatized mantle wedge, and induced mantle partial melting that produced the magma. Those deposits occurred in a continental arc tectonic setting, which is similar to the continental margin arc environment of the ocean-continent subduction setting of the Andes metallogenic belt in South America.展开更多
Petrological and geochemical studies of Neo-proterozoic metagabbros were carried out in the Muiswirab area,South Eastern Desert of Egypt.The Muiswirab area comprises of ophiolitic metagabbroic rocks(MOM),which are tec...Petrological and geochemical studies of Neo-proterozoic metagabbros were carried out in the Muiswirab area,South Eastern Desert of Egypt.The Muiswirab area comprises of ophiolitic metagabbroic rocks(MOM),which are tectonically thrusted over a thick pile of metavolcanic rocks and intruded by syn-and post-tectonic granitoid rocks.The whole-rock geochemical variations coupled with chemical compositions of mineral constituents are used to attain the genesis and tectonic evolution of the studied metagabbros.The geothermobarometric investiga-tion of the analyzed amphiboles from(MOM)revealed that these metagabbros underwent regional metamorphism under lower to upper greenschist facies(biotite zone)conditions(at a temperature of 450 to 500℃and pressure of 1-3 kbar).Geochemically,the metagabbros(MOM)show tholeiitic affinity and cxhibiting both arc-and MORB-like characters as evidenced by their clinopyrox-ene compositions and the Ti/V ratios(11.84-31.65),which considered as prominent features of forearc tectonic regime.The geochemical features suggest a probable fractionation of olivine±clinopyroxene±plagioclase as well as insignificant crustal contamination.The parental magma of the investigated MOM rocks seems to be developed in a sub-arc mantle wedge setting due to the enrichments of LILE(e.g..Rb,Ba,Sr,Pb)over HFSE(e.g,Ti,Nb,Y,Zr,Hf,Ta).The studied MOM rocks have lower values of Nb/U relative to MORB and OIB indicating that their geochemical variation produced due to the enrichment of a lithosphere mantle by OIB like components.The ratios of Zn/Fet,La/Sm,Sm/Yb,Th/Yb and Nb/Yb indicate that the MOM rocks represent a fragment of oceanic crust originated at a supra-subduction zone environment and their parental magma developed by 5-30%partial melting of a spinel lherzolite mantle rather than pyroxenite in an island arc setting and conformable with most of the Egyptian ophiolitic metagabbros.展开更多
It has been five years since the Belt and Road Initiative (BRI) was first introduced. Though there has been a growing body of literature on regional cooperation between covered countries, Japan and South Korea have be...It has been five years since the Belt and Road Initiative (BRI) was first introduced. Though there has been a growing body of literature on regional cooperation between covered countries, Japan and South Korea have been barely discussed. This paper starts with the consensus-based mechanism of a China-Japan-South Korea Free Trade Area (FTA) to probe the approach of its alignment with the BRI in terms of the sequence of “master plans,”“viability of cooperation,” and “embedding of rules.” This inquiry found that the three countries have a shared interest in cooperation in Central Asia to which China prefers a pragmatic approach, while Japan and South Korea an approach combining idealism with pragmatism. Given the huge potential of cooperation between the trio, it is suggested that a “Central Asia chapter” be incorporated in the negotiation framework of this trilateral FTA, and that the design feature three aspects;fundamental principles, specific rules, and an executive body with a view to functionally contributing to regional trade integration in Asia. This approach may also be applied to the alignment of other Asian areas with the BRI.展开更多
文摘The Huanggang intrusive complex in northern Tongbai area was formed in Early Paleozoic. It mainly consists of ultra basic, basic, intermediate and acid rocks, dominated by intermediate and basic rocks. The complex belongs to calc alkaline series. Geochemical characteristics of major and trace elements show that the complex was derived from the fractional crystallization of co source magma. It is suggested that the complex was formed in island arc tectonic environment and was closely related to the northward subduction of the Erlangping back arc basin. Thus, the subduction of the back arc basin can induce the island arc type magmatism similar to the one formed in the setting of ocean plate subduction.
基金jointly supported by Public Science and Technology Research Funds Projects (201511017)
文摘The Duolong area is the most important part of the Western Bangong-Nujiang Suture Zone porphyry Cu（Au） metallogenic belt, in Tibet, China. Here new detailed data are presented from LAICP-MS zircon U-Pb, whole-rock geochemical, and in-situ zircon Hf isotope analyses for igneous rocks in the large Naruo deposit（2.51 Mt of Cu and 82 t of Au） which is located ~2 km NE of the Duolong（Duobuza and Bolong） super-large gold-rich porphyry copper deposit. We integrated our results with previous research of other porphyry deposits in the Duolong area and have identified the timing, geodynamic setting, and petrogenesis of the mineralization-associated magmatic events. Based on the measurements, the Duolong area porphyry Cu（Au） deposit formations are associated with Early Cretaceous intermediate-felsic magmatism, which is consistent with U-Pb zircon ages of 120 Ma. All the main intrusive rocks in the ore-concentrated area have similar lithogeochemical characteristics; they show a relative enrichment in both light rare earth elements（LREEs） and large-ion lithophile elements（LILEs： Rb, Ba, K, etc.） and relative depletion in both heavy rare earth elements（HREEs） and high field strength elements（HFSEs： Nb, Ta, Zr, Hf, etc.）. Moreover, the granite porphyry shows positive εHf（t） values between 1.38–7.37 suggesting that magmas were potentially derived from the partial melting of a depleted mantle wedge that had been metasomatized by subducted slab-derived fluids or melts. This paper points out that the formation of the porphyry-epithermal Cu（Au） deposit in the Duolong area was dominated by northward subduction of the Bangongco Tethys Plate beneath the Qiangtang block in the Early Cretaceous（124–114 Ma）, when the subducted oceanic crust reached 50–70 km underground and generated different degrees of phase transformation, which lead to a melt produced by dehydration of amphibole minerals, a metasomatized mantle wedge, and induced mantle partial melting that produced the magma. Those deposits occurred in a continental arc tectonic setting, which is similar to the continental margin arc environment of the ocean-continent subduction setting of the Andes metallogenic belt in South America.
文摘Petrological and geochemical studies of Neo-proterozoic metagabbros were carried out in the Muiswirab area,South Eastern Desert of Egypt.The Muiswirab area comprises of ophiolitic metagabbroic rocks(MOM),which are tectonically thrusted over a thick pile of metavolcanic rocks and intruded by syn-and post-tectonic granitoid rocks.The whole-rock geochemical variations coupled with chemical compositions of mineral constituents are used to attain the genesis and tectonic evolution of the studied metagabbros.The geothermobarometric investiga-tion of the analyzed amphiboles from(MOM)revealed that these metagabbros underwent regional metamorphism under lower to upper greenschist facies(biotite zone)conditions(at a temperature of 450 to 500℃and pressure of 1-3 kbar).Geochemically,the metagabbros(MOM)show tholeiitic affinity and cxhibiting both arc-and MORB-like characters as evidenced by their clinopyrox-ene compositions and the Ti/V ratios(11.84-31.65),which considered as prominent features of forearc tectonic regime.The geochemical features suggest a probable fractionation of olivine±clinopyroxene±plagioclase as well as insignificant crustal contamination.The parental magma of the investigated MOM rocks seems to be developed in a sub-arc mantle wedge setting due to the enrichments of LILE(e.g..Rb,Ba,Sr,Pb)over HFSE(e.g,Ti,Nb,Y,Zr,Hf,Ta).The studied MOM rocks have lower values of Nb/U relative to MORB and OIB indicating that their geochemical variation produced due to the enrichment of a lithosphere mantle by OIB like components.The ratios of Zn/Fet,La/Sm,Sm/Yb,Th/Yb and Nb/Yb indicate that the MOM rocks represent a fragment of oceanic crust originated at a supra-subduction zone environment and their parental magma developed by 5-30%partial melting of a spinel lherzolite mantle rather than pyroxenite in an island arc setting and conformable with most of the Egyptian ophiolitic metagabbros.
基金funded by the Fundamental Research Funds for the Central Universities
文摘It has been five years since the Belt and Road Initiative (BRI) was first introduced. Though there has been a growing body of literature on regional cooperation between covered countries, Japan and South Korea have been barely discussed. This paper starts with the consensus-based mechanism of a China-Japan-South Korea Free Trade Area (FTA) to probe the approach of its alignment with the BRI in terms of the sequence of “master plans,”“viability of cooperation,” and “embedding of rules.” This inquiry found that the three countries have a shared interest in cooperation in Central Asia to which China prefers a pragmatic approach, while Japan and South Korea an approach combining idealism with pragmatism. Given the huge potential of cooperation between the trio, it is suggested that a “Central Asia chapter” be incorporated in the negotiation framework of this trilateral FTA, and that the design feature three aspects;fundamental principles, specific rules, and an executive body with a view to functionally contributing to regional trade integration in Asia. This approach may also be applied to the alignment of other Asian areas with the BRI.
