core/ A9135E Earth core and lower mantleIn this paper we elaborate on suggestions in the recent literature that the mantle convects uniformly through its entire depth. The main novel feature introduced here, which leads to a satisfactory account of earth temperatures, it the assumption of a ...
The phase change significantly heats plumes that rise from the lower mantle and penetrate into the upper mantle. 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...
discontinuities seems to reflect a level of separation between the top of the transition zone and the base.;Plate-scale processes represented by the subduction of the Farallon plate, are observed to influence both the 410 and the 660, supporting penetration of the slab into the lower mantle. Ev...
As a consequence, lower temperature, higher viscosity and less vigorous flow system characterized the mantle convection. This research has been supported by the Hungarian Scientific Research Fund (OTKA K-72665) and it was implemented thanks to the scholarship in the framework of the TÁMOP 4.2.4...
This convection pattern is inconsistent with that inferred from the geodesic observation of the Venus or Mars. Additional effect of the stratified viscosity at the upper/lower mantle (the viscosity contrast is varied from 30 to 300) are investigated. It is found that the combination of the ...
Carbon in the upper mantle controls incipient melting of carbonated peridotite and so acts as a critical driver of plate tectonics. The carbon-rich melts that form control the rate of volatile outflux from the Earth’s interior, contributing to climate evolution over geological times. However, att...
Convective circulation of the mantle causes deflections of the Earth's surface that vary as a function of space and time. Accurate measurements of this dynamic topography are complicated by the need to isolate and remove other sources of elevation, arising from flexure and lithospheric isostasy. The...
Comparison of the chemical and crustal distributions between ancient and current N-MORB show that the oceanic crust older than 80 Ma has significantly lower Na8.0,Zr/Y, Sm/YbN, and higher CaO/Al2O3,Fe8.0 and crustal thickness. Quantitative modeling of these results suggests that the mantle ...
H Bunge,MA Richards,JR Baumgardner - 《Journal of Geophysical Research Solid Earth》 被引量: 212发表: 2007年 Dynamical consequences in the lower mantle with the post-perovskite phase change and strongly depth-dependent thermodynamic and transport properties We have carried out numerical simulations of...
It has been proposed that Earth's interior has a fundamental discontinuity at mid-mantle depths of ∼400-1000 km, marking the mantle transition zone (MTZ) between mantle layers below and above (e.g., Bullen, 1940, 1947). The lower boundary of the MTZ was later reclassified as the 660...