Mineralogy of peridotite and basalt at the earth's lower-mantle pressures

CaSiO3 perovskite at lower mantle pressures

[1] We investigate by first-principles the structural behavior of CaSiO3 perovskite up to lower mantle pressures. We confirm that the cubic perovskite modification is unstable at all pressures. The zero Kelvin structure is stabilized by SiO6 octahedral rotations that lower the symmetry to tetragonal, orthorhombic, rhombohedral, or to a cubic supercell. The resulting structures have comparable e...

Deformation of polycrystalline MgO at pressures of the lower mantle

[1] Room temperature investigations on the shear strength, elastic moduli, elastic anisotropy, and deformation mechanisms of MgO (periclase) are performed in situ up to pressures of 47 GPa using radial X-ray diffraction and the diamond anvil cell. The calculated elastic moduli are in agreement with previous Brillouin spectroscopy studies. The uniaxial stress component in the polycrystalline MgO...

Plastic deformation of MgGeO3 post-perovskite at lower mantle pressures.

Polycrystalline MgGeO3 post-perovskite was plastically deformed in the diamond anvil cell between 104 and 130 gigapascals confining pressure and ambient temperature. In contrast with phenomenological considerations suggesting (010) as a slip plane, lattice planes near (100) became aligned perpendicular to the compression direction, suggesting that slip on (100) or (110) dominated plastic deform...

2.03 Mineralogy of the Earth – Phase Transitions and Mineralogy of the Lower Mantle

2.03.

Calculating melting temperatures and pressures of peridotite protoliths: Implications for the origin of cratonic mantle