Seismic observations recorded by an African seismic array reveal a low velocity anomaly at the base of the mantle beneath the Indian Ocean, with steeply dipping edges, rapidly varying thicknesses and geometries, and anomalously low shear wave velocities decreasing from 32% at 200 km above the core^mantle boundary to 39% to 312% at the core^ mantle boundary (relative to the preliminary reference...

[1] The ‘‘transition zone water filter’’ model of mantle convection attempts to reconcile geochemical evidence for isolated mantle reservoirs with geophysical evidence for whole mantle circulation by decoupling incompatible elements from bulk mantle circulation via a melt layer above the 410 km discontinuity. This would result in a stratified heating distribution similar to layered convection m...

Paleomagnetic data provide one of the few probes available to interrogate early evolution of the core. Here we apply this probe by examining the latitudinal dependence of paleosecular variation (PSV) data derived from high-quality paleomagnetic data collected from Proterozoic and Neoarchean rocks. These data define a Neoarchean geomagnetic field that was more dipolar than that during Proterozoi...

The propagation of shear waves in an anisotropic fluid saturated porous layer over a prestressed semi-infinite homogeneous elastic half-space lying under an elastic homogeneous layer with irregularity present at the interface with rigid boundary has been studied. The rectangular irregularity has been taken in the half-space. The dispersion equation for shear waves is derived by using the pertur...

Continent–continent collisions are an important tectonic process and have played a fundamental role in the evolution of the modern continents. A combination of geological and geophysical data has provided new constraints on the structure and temporal evolution of these orogens. Magnetotelluric (MT) studies have been an important part of these studies since they can constrain the fluid content a...

Abstract The electrical conductivity is an important geophysical parameter connected to the thermal, chemical, and mineralogical state of Earth’s mantle. In this paper, we apply previously developed methodology forward inverse EM induction modeling latest version satellite-derived spherical harmonic coefficients external internal magnetic field, obtain first 3-D mantle models with contributions...

We consider three independent methodologies for calculating thermal equation of state (EOS) of the major earth-forming mineral, orthorhombic MgSiO3 perovskite: molecular dynamics (MD), lattice dynamics (LD) and Debye model (DM). Using the most recent developments in the GULP code, we derive a new interatomic potential, which is demonstrated to be extremely robust at both high temperatures and h...

Mantle plumes are hypothetical hot, narrow mantle upwellings that are often invoked to explain hotspot volcanism with unusual geophysical and geochemical characteristics. The mantle plume is a well-established geological structure in computer modeling and laboratory experiments but an undisputed seismic detection of one has yet to be made. Vertically continuous low shear velocity anomalies in t...

In this study, we determined the lithospheric electrical structure beneath Handan-Xingtai district and its adjacent regions using magnetotelluric sounding data. To west of district, crust upper mantle Taihang Mountains are mainly characterized by high resistivity (>1000 Ωm, which interpreted to be relic cratonic lithosphere. contrast, lithosphere North China Plain east shows high-conductivit...