Recent seismological studies demonstrate the presence of strong deep-mantle elastic heterogeneity and anisotropy, consistent with a dynamic environment having chemical anomalies, phase changes, and partially molten material. The implications for deep-mantle plume genesis are discussed in the light of the seismological findings. Nearly antipodal large low–shear velocity provinces (LLSVPs) in the...

Recent seismological evidences imply that the boundary between the lithosphere and asthenosphere is a compositional boundary in the oceanic upper mantle, and a rapid increase of viscosity at this boundary is suggested. We modeled a thermal convection in the oceanic mantle numerically using the finite element method, and investigated geodynamical consequences of such a rheological layering. Earl...

[1] Mars Odyssey Gamma-Ray Spectrometer (GRS) neutron spectrometer data are analyzed to determine the concentration and boundary of buried water ice near the south pole. The measurements are consistent with a circumpolar layer of average ice concentration from 35 to 100% by weight and superposed dust with thickness density product 30 to 40 g/cm. The region of buried water ice extends from near ...

In situ observations of the perovskite–CaIrO3 phase transition in MgSiO3 and in pyrolitic compositions were carried out using a laser-heated diamond anvil cell interfaced with a synchrotron radiation source. For pure MgSiO3, the phase boundary between the orthorhombic Mg-perovskite and CaIrO3-type phases in the temperature range of 1300–3100 K was determined to be P (GPa)=130 (F3)+0.0070 (F0.00...

We pursue accurate numerical techniques to obtain theoretical seismic waves for realistic three dimensional (3-D) Earth models using Spectral-Element Method. We have tried to solve forward problem, that is, to calculate synthetic seismic waveform for fully 3-D Earth model. We introduce a heterogeneous region at Earth's core-mantle boundary by combining a small, strongly anomalous region to a la...

[1] Anomalous boundary layer structure at the core-mantle boundary (CMB) is investigated using a global set of broadband SKS and SPdKS waves from permanent and portable broadband seismometer arrays. SPdKS is an SKS wave that intersects the CMB at the critical angle for ScP, thus initiating a diffracted P wave (Pdiff) along the CMB at the core entry and exit locations. The waveshape and timing o...

Hot spot volcanism may originate from the deep mantle in regions exhibiting the Earth’s most pronounced lateral S-wave velocity gradients. These strong gradient regions display an improved geographic correlation over S-wave velocities to surface hot spot locations. For the lowest velocities or strongest gradients occupying 10% of the surface area of the core–mantle boundary (CMB), hot spots are...

The effect on composition and evoconvection with the entire mantle passing through lution of the mantle of the recently-observed the partial melt zone. Thus the lower mantle was strong concentration of iron in (Mg, Fe)O-magnedepleted of iron relative to both the upper siow•stite (row) at the expense of (Mg, Fe)SiO•mantle and the mantles of the small terrestrial perovskite (pv) structure is stud...

Almost no in situ seismic data are available for Venus; therefore, we can constrain the deep structure of this planet only from geodetic obtained by spacecraft. Of particular interest is Venus’s core-mantle boundary, which holds clues about origin and evolution celestial body. In study, build a series different mantle/core models Venus based on several mantle composition compare their associate...

Extreme variations of Earth's magnetic field occurred in the Levant region around 1000 BC, when the field intensity rapidly rose and fell by a factor of 2. No coherent link currently exists between this intensity spike and the global field produced by the core geodynamo. Here we show that the Levantine spike must span >60° longitude at Earth's surface if it originates from the core-mantle bound...