The high pressure and high temperature(HPHT) method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O an...The high pressure and high temperature(HPHT) method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O and Al2(SiO3)3.Through the HPHT method, the amorphous glass material is entirely converted into crystalline jadeite. We can obtain the good-quality jadeite by optimizing the reaction pressure and temperature. The measurements of x-ray diffraction(XRD),scanning electron microscopy(SEM), Fourier-transform infrared(FTIR) and Raman scattering indicate that the properties of synthesized jadeite at 1260℃ under 3.5 GPa are extremely similar to those of the natural jadeite. What is more, the results will be valuable for understanding the formation process of natural jadeite. This work also reveals the mechanism for metamorphism of magma in the earth.展开更多
Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron ...Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron diffraction (SAED) and the high resolution electron microscopy (HREM) are used in this work to study the microstructures and ultrastructures of garnets in the jadeite quartzite from Dabie Mountains, China. The microstructures of the garnet occur mainly as free dislocations, dislocation walls, stacking faults, dislocation networks and sub grain boundaries. The dislocation density is ρ=n ×10 8/cm 2 ( n =1.7—7.5) and the deformation mechanism is the dislocation glide and dynamic recovery. The superstructures of the garnet crystal revealed by HREM occur mainly as dislocations, faults, domain structures and lattice deformations, indicating the strong stress during the formation of the jadeite quartzite.展开更多
Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects...Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects in jadeite by the plane-wave pseudo-potential method based on density functional theory, and optimized the atomic positions and lattice constants in all configurations (different defective systems). Incorporation mechanisms considered for hydrogen (H) in jadeite include: (1) hydrogen incorporating with the 02 site oxygen and coexisting with M2 vacancy; (2) one H atom combined with an AI atom replacing Si in tetrahedron; (3) 4H atoms directly replacing Si in tetrahedron and (4) 3H atoms replacing Al on the M1 site. The four incorporation mechanisms mentioned above form the corresponding VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects. The molecular dynamics simulation to the ideal, VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects under the P-T conditions of 900 K, 2 GPa, the Vsa-Hi and Alsi-Hi point defects under different pressures at T = 900 K, and Alsj-Hj point defects under different temperatures at P = 3 GPa was performed to examine the preferential mode of hydrogen incorporation in jadeite by means of first-principles calculations. The calculations show that the averaged O-H bond-length in the hydrogen point defects system decreased in the order of Alsi-Hi, VNa-HI, Vsl-4Hf and VAI-3Hi. VNa-HI complex defects result in a contraction of the jadeite volume and the presence of Alsi-Hi, Vsi-4H~ and VAI-3Hi defects could increase the superceli volume, which is the most obvious in the VAt-3Hi defects. The energy of formation of Also-HI and VA[-3HI complex defects was much lower than that of other defect systems. The VAI-3Hi defects system has the lowest energy and the shortest O-H bond-length, suggesting that this system is the most favorable. The analytical results of vacancy formation energy, O-H bond- length, and the stability of the hydrogen defects in jadeite have suggested that the preferred hydration incorporation mode in jadeite is VAI-3Hi complex defect.展开更多
A lot of liquid-gas and liquid-gas-solid inclusions were found in Pharkant jadeitites, northwestern Myanmar and their characteristics, geological setting and porphyroclastic jadeites with inclusions in them were descr...A lot of liquid-gas and liquid-gas-solid inclusions were found in Pharkant jadeitites, northwestern Myanmar and their characteristics, geological setting and porphyroclastic jadeites with inclusions in them were described in detail. The results analyzed by Raman spectrometer showed that the component of liquid-gas phase and solid phase (daughter minerals) in fluid inclusions is H2O + CH4 and jadeite separately. The results indicated that Pharkant jadeitites were crystallized from H2O + CH4 bearing jadeitic melt which may originate from mantle. The P-T conditions in which the jadeitites were crystallized were speculated to be T】650℃, P】1.5 GPa.展开更多
Diamonds commonly occur in kimberlites, lamproites and relative alluvial sediments. Some examples of diamonds discovered in ultramafics have heen reported. Sobolev and Shatsky reported diamonds from high-pressure meta...Diamonds commonly occur in kimberlites, lamproites and relative alluvial sediments. Some examples of diamonds discovered in ultramafics have heen reported. Sobolev and Shatsky reported diamonds from high-pressure metamorphic rock from northern Kazakhstan and considered it to be the source of the alluvial diamonds in Pridneprovie region of western U. S. S. R. Diamonds reported here show some similarity to those in northern Kazakhstan, and are the second occurrence in the world, but the first one in China.展开更多
The structural properties of jadeite at high pressures (0.000 1-30 GPa) are investigated using plane-wave pseudopotential density functional theory method. As a function of pressure, the monoclinic cell parameters w...The structural properties of jadeite at high pressures (0.000 1-30 GPa) are investigated using plane-wave pseudopotential density functional theory method. As a function of pressure, the monoclinic cell parameters were calculated and the compressibility coefficients are 0.002 6, 0.002 3 and 0.002 6 GPal, respectively. The bond length, bond angle and distortion variation were studied in order to obtain the information of polyhedral compression. The pressure-volume equation of state was con- sidered in order to obtain the bulk modulus K0. Comparison between the calculated K0 values and the experimental data suggested that the model provides reasonable insights into crystallographic and physical properties of jadeite.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51172089 and 51171070)the Graduate Innovation Fund of Jilin University,China(Grant No.2016065)
文摘The high pressure and high temperature(HPHT) method is successfully used to synthesize jadeite in a temperature range of 1000℃–1400℃ under a pressure of 3.5 GPa. The initial raw materials are Na2SiO3·9H2O and Al2(SiO3)3.Through the HPHT method, the amorphous glass material is entirely converted into crystalline jadeite. We can obtain the good-quality jadeite by optimizing the reaction pressure and temperature. The measurements of x-ray diffraction(XRD),scanning electron microscopy(SEM), Fourier-transform infrared(FTIR) and Raman scattering indicate that the properties of synthesized jadeite at 1260℃ under 3.5 GPa are extremely similar to those of the natural jadeite. What is more, the results will be valuable for understanding the formation process of natural jadeite. This work also reveals the mechanism for metamorphism of magma in the earth.
基金This paperis supported by the National Natural Science Foundation of China( No.49872 0 69)
文摘Garnet is an important rock forming mineral of high pressure and ultrahigh pressure metamorphic rocks. Its popular isomorphism complicates its chemical composition and crystal structure. The selected area electron diffraction (SAED) and the high resolution electron microscopy (HREM) are used in this work to study the microstructures and ultrastructures of garnets in the jadeite quartzite from Dabie Mountains, China. The microstructures of the garnet occur mainly as free dislocations, dislocation walls, stacking faults, dislocation networks and sub grain boundaries. The dislocation density is ρ=n ×10 8/cm 2 ( n =1.7—7.5) and the deformation mechanism is the dislocation glide and dynamic recovery. The superstructures of the garnet crystal revealed by HREM occur mainly as dislocations, faults, domain structures and lattice deformations, indicating the strong stress during the formation of the jadeite quartzite.
基金supported by the National Natural Science Foundation of China (grants No.41172051 and 41472042)the Specialized Research Fund for the Doctoral Program of Higher Education of China (grant No.20060491504)
文摘Hydrogen incorporation is critical for explaining defect energies, structure parameters and other physical characteristics of minerals and understanding mantle dynamics. This work analyzed the hydrogen complex defects in jadeite by the plane-wave pseudo-potential method based on density functional theory, and optimized the atomic positions and lattice constants in all configurations (different defective systems). Incorporation mechanisms considered for hydrogen (H) in jadeite include: (1) hydrogen incorporating with the 02 site oxygen and coexisting with M2 vacancy; (2) one H atom combined with an AI atom replacing Si in tetrahedron; (3) 4H atoms directly replacing Si in tetrahedron and (4) 3H atoms replacing Al on the M1 site. The four incorporation mechanisms mentioned above form the corresponding VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects. The molecular dynamics simulation to the ideal, VNa-Hi, Alsi-Hi, Vsi-4Hi and VAr3Hi point defects under the P-T conditions of 900 K, 2 GPa, the Vsa-Hi and Alsi-Hi point defects under different pressures at T = 900 K, and Alsj-Hj point defects under different temperatures at P = 3 GPa was performed to examine the preferential mode of hydrogen incorporation in jadeite by means of first-principles calculations. The calculations show that the averaged O-H bond-length in the hydrogen point defects system decreased in the order of Alsi-Hi, VNa-HI, Vsl-4Hf and VAI-3Hi. VNa-HI complex defects result in a contraction of the jadeite volume and the presence of Alsi-Hi, Vsi-4H~ and VAI-3Hi defects could increase the superceli volume, which is the most obvious in the VAt-3Hi defects. The energy of formation of Also-HI and VA[-3HI complex defects was much lower than that of other defect systems. The VAI-3Hi defects system has the lowest energy and the shortest O-H bond-length, suggesting that this system is the most favorable. The analytical results of vacancy formation energy, O-H bond- length, and the stability of the hydrogen defects in jadeite have suggested that the preferred hydration incorporation mode in jadeite is VAI-3Hi complex defect.
文摘A lot of liquid-gas and liquid-gas-solid inclusions were found in Pharkant jadeitites, northwestern Myanmar and their characteristics, geological setting and porphyroclastic jadeites with inclusions in them were described in detail. The results analyzed by Raman spectrometer showed that the component of liquid-gas phase and solid phase (daughter minerals) in fluid inclusions is H2O + CH4 and jadeite separately. The results indicated that Pharkant jadeitites were crystallized from H2O + CH4 bearing jadeitic melt which may originate from mantle. The P-T conditions in which the jadeitites were crystallized were speculated to be T】650℃, P】1.5 GPa.
基金Project supported by the National Natural Science Foundation of China and Anhui Bureau of Geology and Minerol Resources.
文摘Diamonds commonly occur in kimberlites, lamproites and relative alluvial sediments. Some examples of diamonds discovered in ultramafics have heen reported. Sobolev and Shatsky reported diamonds from high-pressure metamorphic rock from northern Kazakhstan and considered it to be the source of the alluvial diamonds in Pridneprovie region of western U. S. S. R. Diamonds reported here show some similarity to those in northern Kazakhstan, and are the second occurrence in the world, but the first one in China.
基金supported by the National Natural Science Foundation of China(Nos.41172051,40872039 and 90714002)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20060491504)
文摘The structural properties of jadeite at high pressures (0.000 1-30 GPa) are investigated using plane-wave pseudopotential density functional theory method. As a function of pressure, the monoclinic cell parameters were calculated and the compressibility coefficients are 0.002 6, 0.002 3 and 0.002 6 GPal, respectively. The bond length, bond angle and distortion variation were studied in order to obtain the information of polyhedral compression. The pressure-volume equation of state was con- sidered in order to obtain the bulk modulus K0. Comparison between the calculated K0 values and the experimental data suggested that the model provides reasonable insights into crystallographic and physical properties of jadeite.