基于文献报道的实验数据,采用相图计算(CALPHAD:CALculation of PHAse Diagrams)方法对V-M(M=Li,Na,K,Sc,Ag)5个二元系进行相图热力学研究。通过热力学优化计算获得了一套描述液相、(V)、(Li)、(Na)、(K)、(αSc)、(βSc)和(Ag)相的热...基于文献报道的实验数据,采用相图计算(CALPHAD:CALculation of PHAse Diagrams)方法对V-M(M=Li,Na,K,Sc,Ag)5个二元系进行相图热力学研究。通过热力学优化计算获得了一套描述液相、(V)、(Li)、(Na)、(K)、(αSc)、(βSc)和(Ag)相的热力学参数。V-Li、V-Na和V-K体系中的气相视为由组元V、Li、Li2、Na、Na2、K和K2混合的理想气体。与实验相图数据对比表明,获得的热力学参数能够准确地描述实验相平衡数据。展开更多
基于密度泛函理论的第一性原理的Vienna Ab initio Simulation Package(VASP)软件系统研究了Mg7TMH16(TM=Sc,Ti,V,Y,Zr,Nb)的晶体结构和电子性能.分析了结合能和形成焓,计算得到的结合能显示Mg7TiH16和Mg7NbH16的稳定性最强,形成焓的变...基于密度泛函理论的第一性原理的Vienna Ab initio Simulation Package(VASP)软件系统研究了Mg7TMH16(TM=Sc,Ti,V,Y,Zr,Nb)的晶体结构和电子性能.分析了结合能和形成焓,计算得到的结合能显示Mg7TiH16和Mg7NbH16的稳定性最强,形成焓的变化表明Mg7TMH16具有比MgH2更低的分解温度,电子态密度显示Mg7TMH16表现出明显的金属特性.展开更多
Porphyry copper deposits(PCDs)supply the majority of the world's copper(Cu)as well as significant amounts of molybdenum(Mo)and gold(Au).The formation of these deposits is controlled by a variety of geological fact...Porphyry copper deposits(PCDs)supply the majority of the world's copper(Cu)as well as significant amounts of molybdenum(Mo)and gold(Au).The formation of these deposits is controlled by a variety of geological factors,among which the magmatic oxidation is one of the focuses of current research.This study investigates the redox characteristics of arc magmas by analyzing the ratio of vanadium(V)to scandium(Sc)and its correlation with the oxygen fugacity(fO2)of magmas from arcs of various crustal thicknesses globally.We compiled an extensive dataset of published V/Sc values and studied the partition coefficients of Vand Sc between minerals and silicate melts across various magmatic environments.The results demonstrate that fractional crystallization of magnetite markedly reduces V/Sc values of the residual melt.Furthermore,magnesium number(Mg#)at the onset of magnetite fractionation is strongly positively correlated with fO_(2)of the equilibrium magma.Based on this,the oxidation of arc magmas from different crustal thicknesses can be evaluated.The result suggests that magmas generated in crusts thicker than 20 km tend to be more oxidized with increasing crust thickness.This trend is attributed to enhanced intracrustal differentiation processes involving garnet and amphibole,particularly in mature island and continental arcs.In contrast,magmas in thinner arc crusts(<20 km),which are significantly influenced by subducted slab materials,display higher oxidation states than most of their thicker crust counterparts.These findings suggest that both subduction dynamics and crustal thickness play a vital role in determining the oxidation state of arc magmas and,consequently,their capacity to generate PCDs.Highly oxidized,primitive arc magmas are less favorable for PCD formation due to that they tend to experience magnetite fractionation and thus sulfide saturation in the early stage of magma evolution,a process leading to copper depletion.On the contrary,thick arcs where magnetite crystallization is widely suppressed and therefore more conducive to retaining Cu in evolved magmas.This study highlights the coupled roles of subduction input and intra-crustal differentiation in the genesis of arc magmatic oxidation,and provides geochemical indications for the metal endowment of porphyry copper deposits based on the V/Sc systematics.展开更多
文摘基于文献报道的实验数据,采用相图计算(CALPHAD:CALculation of PHAse Diagrams)方法对V-M(M=Li,Na,K,Sc,Ag)5个二元系进行相图热力学研究。通过热力学优化计算获得了一套描述液相、(V)、(Li)、(Na)、(K)、(αSc)、(βSc)和(Ag)相的热力学参数。V-Li、V-Na和V-K体系中的气相视为由组元V、Li、Li2、Na、Na2、K和K2混合的理想气体。与实验相图数据对比表明,获得的热力学参数能够准确地描述实验相平衡数据。
文摘基于密度泛函理论的第一性原理的Vienna Ab initio Simulation Package(VASP)软件系统研究了Mg7TMH16(TM=Sc,Ti,V,Y,Zr,Nb)的晶体结构和电子性能.分析了结合能和形成焓,计算得到的结合能显示Mg7TiH16和Mg7NbH16的稳定性最强,形成焓的变化表明Mg7TMH16具有比MgH2更低的分解温度,电子态密度显示Mg7TMH16表现出明显的金属特性.
基金supported by the National Natural Science Foundation of China(Grant Nos.41921003,42230810,41902089)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2023B1212060048)the Guangzhou Basic and Applied Basic Research Subject(Young Doctor Sailing Project)(Grant No.2024A04J4828)。
文摘Porphyry copper deposits(PCDs)supply the majority of the world's copper(Cu)as well as significant amounts of molybdenum(Mo)and gold(Au).The formation of these deposits is controlled by a variety of geological factors,among which the magmatic oxidation is one of the focuses of current research.This study investigates the redox characteristics of arc magmas by analyzing the ratio of vanadium(V)to scandium(Sc)and its correlation with the oxygen fugacity(fO2)of magmas from arcs of various crustal thicknesses globally.We compiled an extensive dataset of published V/Sc values and studied the partition coefficients of Vand Sc between minerals and silicate melts across various magmatic environments.The results demonstrate that fractional crystallization of magnetite markedly reduces V/Sc values of the residual melt.Furthermore,magnesium number(Mg#)at the onset of magnetite fractionation is strongly positively correlated with fO_(2)of the equilibrium magma.Based on this,the oxidation of arc magmas from different crustal thicknesses can be evaluated.The result suggests that magmas generated in crusts thicker than 20 km tend to be more oxidized with increasing crust thickness.This trend is attributed to enhanced intracrustal differentiation processes involving garnet and amphibole,particularly in mature island and continental arcs.In contrast,magmas in thinner arc crusts(<20 km),which are significantly influenced by subducted slab materials,display higher oxidation states than most of their thicker crust counterparts.These findings suggest that both subduction dynamics and crustal thickness play a vital role in determining the oxidation state of arc magmas and,consequently,their capacity to generate PCDs.Highly oxidized,primitive arc magmas are less favorable for PCD formation due to that they tend to experience magnetite fractionation and thus sulfide saturation in the early stage of magma evolution,a process leading to copper depletion.On the contrary,thick arcs where magnetite crystallization is widely suppressed and therefore more conducive to retaining Cu in evolved magmas.This study highlights the coupled roles of subduction input and intra-crustal differentiation in the genesis of arc magmatic oxidation,and provides geochemical indications for the metal endowment of porphyry copper deposits based on the V/Sc systematics.
