Iron-rich post-perovskite and the origin of ultralow-velocity zones.
The boundary layer between the crystalline silicate lower mantle and the liquid iron core contains regions with ultralow seismic velocities. Such low compressional and shear wave velocities and high Poisson's ratio are also observed experimentally in post-perovskite silicate phase containing up to 40 mol% FeSiO3 endmember. The iron-rich post-perovskite silicate is stable at the pressure-temperature and chemical environment of the core-mantle boundary and can be formed by core-mantle reaction. Mantle dynamics may lead to further accumulation of this material into the ultralow-velocity patches that are observable by seismology.
Mao
Wendy L
WL
Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. wmao@lanl.gov
Mao
Ho-Kwang
HK
Sturhahn
Wolfgang
W
Zhao
Jiyong
J
Prakapenka
Vitali B
VB
Meng
Yue
Y
Shu
Jinfu
J
Fei
Yingwei
Y
Hemley
Russell J
RJ