The Damiao Fe-Ti-P ore deposit,hosted in the;.74 Ga Damiao anorthosite complex,is the only known anorthosite-hosted deposit in China.The deposit contains hundreds of ore bodies occurring as irregular lenses,veins
The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sh...The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sharp contacts against anorthosite and gabbronorite.This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures,including blocky,lamellar,and cloth-like forms.In this study,we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process.Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms:oxy-exsolution due to titanomagnetite oxidation;subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe,Ti,Cr,Co,and Ni;and exsolution related to lattice defects caused by rapid cooling.Thermodynamic modeling using Gibbs free energy calculations,and the QUILF program indicates that blocky,lamellar,and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity.Additionally,our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al,due to the oxidation of titanomagnetite,rather than interactions between ilmenite and adjacent clinopyroxene.Reconstruction of the cooling history suggests that the oxygen fugacity of oxide-apatite gabbronorites was significantly higher than that of Fe-Ti-P ores.This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility,leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.展开更多
Magmatic oxide deposits in the～260 Ma Emeishan Large Igneous Province（ELIP）,SW China and northern Vietnam,are important sources of Fe,Ti and V.Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua,Hongg...Magmatic oxide deposits in the～260 Ma Emeishan Large Igneous Province（ELIP）,SW China and northern Vietnam,are important sources of Fe,Ti and V.Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua,Hongge,and Baima deposits,are well described in the literature and are hosted in layered mafic-ultramafic intrusions in the Panxi region,the central ELIP.The same type of ELIP- related deposits also occur far to the south and include the Anyi deposit,about 130 km south of Panzhihua,and the Mianhuadi deposit in the Red River fault zone.The Anyi deposit is relatively small but is similarly hosted in a layered mafic intrusion.The Mianhuadi deposit has a zircon U-Pb age of～260 Ma and is thus contemporaneous with the ELIP.This deposit was variably metamorphosed during the Indosinian orogeny and Red River faulting.Compositionally,magnetite of the Mianhuadi deposit contains smaller amounts of Ti and V than that of the other deposits,possibly attributable to the later metamorphism.The distribution of the oxide ore deposits is not related to the domal structure of the ELIP.One major feature of all the oxide deposits in the ELIP is the spatial association of oxide-bearing gabbroic intrusions,syenitic plutons and high-Ti flood basalts.Thus,we propose that magmas from a mantle plume were emplaced into a shallow magma chamber where they were evolved into a field of liquid immiscibility to form two silicate liquids,one with an extremely Fe-Ti-rich gabbroic composition and the other syenitic.An immiscible Fe-Ti-（P） oxide melt may then separate from the mafic magmas to form oxide deposits.The parental magmas from which these deposits formed were likely Fe-Ti-rich picritic in composition and were derived from enriched asthenospheric mantle at a greater depth than the magmas that produced sulfide-bearing intrusions of the ELIP.展开更多
P/M Ti-Fe-Mo-Y alloys with different Rare-earth Y Content are prepared by blend element method, its sintering and hot deformation behaviors are studied together with microstructure and mechanical properties. The micro...P/M Ti-Fe-Mo-Y alloys with different Rare-earth Y Content are prepared by blend element method, its sintering and hot deformation behaviors are studied together with microstructure and mechanical properties. The microstructures and properties of the alloying titanium were testified by the analysis of Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM).The result indicated that Y element absorbs free oxygen and purify the Ti powder surface, promoting densification process. With appropriate vacuum and temperature, the blend element metal powder sintering relative density can reach more than 97%. Microstructure and mechanical properties analysis shown that Y element composed Y2O3 particles which refine grains and improve plasticity, elevate alloy distortion ability. After hot deformation, grains crashed and flow line appears, the mechanical properties of Ti-Fe-Mo-Y alloy prompted which also validated by large amount of dimples appear in tensile fracture surface.展开更多
文摘The Damiao Fe-Ti-P ore deposit,hosted in the;.74 Ga Damiao anorthosite complex,is the only known anorthosite-hosted deposit in China.The deposit contains hundreds of ore bodies occurring as irregular lenses,veins
基金funded by the National Natural Science Foundation of China(grant 42102094)Natural Science Foundation of Hebei(Grant D2022402028).
文摘The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sharp contacts against anorthosite and gabbronorite.This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures,including blocky,lamellar,and cloth-like forms.In this study,we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process.Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms:oxy-exsolution due to titanomagnetite oxidation;subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe,Ti,Cr,Co,and Ni;and exsolution related to lattice defects caused by rapid cooling.Thermodynamic modeling using Gibbs free energy calculations,and the QUILF program indicates that blocky,lamellar,and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity.Additionally,our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al,due to the oxidation of titanomagnetite,rather than interactions between ilmenite and adjacent clinopyroxene.Reconstruction of the cooling history suggests that the oxygen fugacity of oxide-apatite gabbronorites was significantly higher than that of Fe-Ti-P ores.This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility,leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.
基金supported by the Research Grant Council of Hong Kong(HKU707012P)to MFZfrom a Chinese National "973" project (2011CB808903)+1 种基金a "CAS Hundred Talents" project under Chinese Academy of Sciences to CYWSouth African National Science Foundation Grant SA/China Project 67220 to SP and MFZ
文摘Magmatic oxide deposits in the～260 Ma Emeishan Large Igneous Province（ELIP）,SW China and northern Vietnam,are important sources of Fe,Ti and V.Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua,Hongge,and Baima deposits,are well described in the literature and are hosted in layered mafic-ultramafic intrusions in the Panxi region,the central ELIP.The same type of ELIP- related deposits also occur far to the south and include the Anyi deposit,about 130 km south of Panzhihua,and the Mianhuadi deposit in the Red River fault zone.The Anyi deposit is relatively small but is similarly hosted in a layered mafic intrusion.The Mianhuadi deposit has a zircon U-Pb age of～260 Ma and is thus contemporaneous with the ELIP.This deposit was variably metamorphosed during the Indosinian orogeny and Red River faulting.Compositionally,magnetite of the Mianhuadi deposit contains smaller amounts of Ti and V than that of the other deposits,possibly attributable to the later metamorphism.The distribution of the oxide ore deposits is not related to the domal structure of the ELIP.One major feature of all the oxide deposits in the ELIP is the spatial association of oxide-bearing gabbroic intrusions,syenitic plutons and high-Ti flood basalts.Thus,we propose that magmas from a mantle plume were emplaced into a shallow magma chamber where they were evolved into a field of liquid immiscibility to form two silicate liquids,one with an extremely Fe-Ti-rich gabbroic composition and the other syenitic.An immiscible Fe-Ti-（P） oxide melt may then separate from the mafic magmas to form oxide deposits.The parental magmas from which these deposits formed were likely Fe-Ti-rich picritic in composition and were derived from enriched asthenospheric mantle at a greater depth than the magmas that produced sulfide-bearing intrusions of the ELIP.
基金National Key Technology R&D Program (2007BAE07B05)
文摘P/M Ti-Fe-Mo-Y alloys with different Rare-earth Y Content are prepared by blend element method, its sintering and hot deformation behaviors are studied together with microstructure and mechanical properties. The microstructures and properties of the alloying titanium were testified by the analysis of Optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM).The result indicated that Y element absorbs free oxygen and purify the Ti powder surface, promoting densification process. With appropriate vacuum and temperature, the blend element metal powder sintering relative density can reach more than 97%. Microstructure and mechanical properties analysis shown that Y element composed Y2O3 particles which refine grains and improve plasticity, elevate alloy distortion ability. After hot deformation, grains crashed and flow line appears, the mechanical properties of Ti-Fe-Mo-Y alloy prompted which also validated by large amount of dimples appear in tensile fracture surface.
