The high-viscosity layer near 2,000 km depth results in a re-organization of flow from short to long horizontal length scales, which agrees with seismic tomographic observations of very long wavelength structures in the deep mantle. The high-viscosity region also strongly suppresses flow-induced ...
Mineralogy of mantle peridotite along a model geotherm up to 700 km depth. In: Manghnani, M.H., Syono, Y. (Eds.), High-Pressure Research in Mineral Physics. AGU, Wash- ington, pp. 427-437.Takahashi, E. & Ito, E., 1987. Mineralogy of mantle peridotite along a model geotherm up ...
In contrast, at 660 km depth both the olivine and nonolivine transitions generate multiple discontinuities and gradients, which could be visible to Pds signals. Seismic observations of a simple 410 km signal and a complex 660 km signal might therefore be expected from the predictions of mineral ...
A better knowledge of the structures at lithospheric and upper mantle scales across the main lithospheric units such as the Siberian craton, the Mongolian plateau, its Hangay dome, and the Gobi–Altay range is required in order to constrain the large-scale processes at depth in this northernmost...
If confirmed, this model would link processes occurring at 2,800 km depth in the Earth to the environmentally catastrophic formation of large igneous provinces at its surface. Trela et al.8 characterize hot komatiitic lavas that erupted relatively recently, in geological terms, above the ...
Finite element numerical modeling has been carried out in order to investigate the effect of the depth- and temperature-dependent viscosity on the thermal convection occurring in the Earth's mantle. Calculations were made in a 2D spherical shell domain applying Boussinesq approximation. It was establi...
The depth extent, density, and dynamical role of apparent subcontinental keels are investigated by using constraints provided by the very long-wavelength representations of several geophysical fields. We first consider local cross correlations between the nonhydrostatic free-air gravity field, the map of...
The Earth's core–mantle boundary (CMB) is the largest density discontinuity in our planet, separating the rocky oxide mantle from the liquid metal core. The structure and dynamics of the CMB region are central to major questions such as the depth extent of lithospheric subduction, the thermal...
The dashed lines from top to bottom mark the 410 km, 660 km discontinuity, and 2791 km (100 km above the core–mantle boundary). B Events and Sdiff ray paths on the background tomography model SEMUCB_WM1 at 2791 km depth50. Beachballs of events plotted in different colors ...
The exothermic phase change from olivine to spinel at a depth of 400 km in the mantle mitigates the effects of the dynamically and thermally dominant endothermic phase transition. 展开 关键词: ANISOTROPY BODY WAVES POLARIZATION SEISMIC-WAVE PROPAGATION DOI: 10.1016/0264-3707(95)00019-6 ...