title: Iron-rich post-perovskite and the origin of ultralow-velocity zones.
abstract: 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.
authors.affiliation: Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. wmao@lanl.gov
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Mao
authors.forename: Ho-Kwang
authors.initials: HK
authors.lastname: Mao
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sturhahn
authors.forename: Jiyong
authors.initials: J
authors.lastname: Zhao
authors.forename: Vitali B
authors.initials: VB
authors.lastname: Prakapenka
authors.forename: Yue
authors.initials: Y
authors.lastname: Meng
authors.forename: Jinfu
authors.initials: J
authors.lastname: Shu
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Fei
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Hemley