Imagen de Portada

First Observation of Quenched Davemaoite to Ambient Conditions: Its Electron Diffraction Pattern

Guardado en:
Publicado en:Geophysical Research Letters vol. 52, no. 19 (Oct 16, 2025)
Autor principal: Miyajima, Nobuyoshi
Otros Autores: Wang, Lin, Katsura, Tomoo
Publicado:
John Wiley & Sons, Inc.
Materias:
Amorphization
Electron microscopy
Transmission electron microscopy
Electron diffraction
Cameras
Silicates
Minerals
Electrons
Spectrum analysis
Cubic lattice
Static pressure
Diffraction
Symmetry
Pressure
Molar volume
Diffraction patterns
Perovskites
Calcium
Environmental
Acceso en línea:Citation/Abstract
Full Text
Full Text - PDF
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
Resumen:Calcium‐rich silicate perovskite (davemaoite) has been for the first time investigated at ambient pressure by electron diffraction in transmission electron microscopy. The obtained diffraction pattern in comparison to that of the coexisting Mg‐rich silicate perovskite (bridgmanite) has revealed the cubic symmetry, Pm3‾ $\overline{3}$m, the lattice parameter a = 0.3561(4) nm and the volume V0 = 45.16(10) Å3 (27.19 cm3/mol), which is still larger molar volume than that of the coexisting bridgmanite (25.49 cm3/mol). With large volume difference davemaoite and bridgmanite coexist at equilibrium under the conditions at 40 GPa and 2,000°C. The nanometer‐sized crystalline davemaoite (4.27 g/cm3) is mantled by the amorphous CaSiO3 (2.82 g/cm3). This core‐mantle structure prevents amorphization of the unstable high‐pressure mineral at the core due to a static pressure, 1.2(10) GPa generated by volume expansion on the transition at the mantle. This mechanism is the same as that of high‐pressure minerals preserved in shocked meteorites.
ISSN:0094-8276
1944-8007
DOI:10.1029/2025GL115280
Fuente:Science Database