Earth's mantleTransition layerVelocity‐density relationsSummary This chapter contains sections titled: Introduction Density distributions for the mantle The nature of the transition layer CoreFrancis BirchAmerican Geophysical Union (AGU)Birch F., 1961; Composition of the earth's mantle, Geophys. J., ...
The composition of Earth's mantle can only be directly observed from mantle rock deposited at Earth's surface which is technically only from the upper mantle. However, through the analysis of these samples, the mantle seems to consist mostly of ultramafic rock like peridotite, which is high in...
Earth, third planet from the Sun and the fifth largest planet in the solar system in terms of size and mass. Its single most outstanding feature is that its near-surface environments are the only places in the universe known to harbor life. Learn more ab
ratios, osmium-isotope ratios and D/H, Ar/H2O and Kr/Xe ratios such that no primitive material similar to the Earth's mantle is currently represented in our meteorite collections. The 'building blocks' of the Earth must instead be composed of unsampled 'Earth chondrite' or 'Earth achondrite...
Compositional Heterogeneity in the Bottom 1000 Kilometers of Earth's Mantle: Toward a Hybrid Convection Model Tomographic imaging indicates that slabs of subducted lithosphere can sink deep into Earth's lower mantle. The view that convective flow is stratified at 660-kilometer depth and preserves a ...
Collectively, they document the tremendous progress in understanding achieved over the past decade or so, but they also demonstrate that many controversies and challenges remain for future collaborative studies of Earth's deep interior.关键词: Earth—Mantle—Research Thermochemistry—Research Seismology—...
The existence of heat-producing elements (U, Th, K) and their highly heterogeneous distribution in the Earth's mantle suggests a link between thermal and chemical properties of the mantle. Previous studies have shown that this chemical–thermal relationship has a strong influence on the mantle con...
High olivine contents of up to 87% are implied by seismic models of the western U.S. and eastern Pacific regions. In contrast, we infer less than 35% olivine under the central Pacific. Strong variations of olivine content and upper mantle lithologies near the 410 km discontinuity are ...
(2006) studied olivines from different planetary bodies (Earth, Mars, Moon and pallasite parent body), with the terrestrial olivines having a range of origins, tectonic settings and mantle source compositions, and found only small variations in the Mg isotopic compositions of these samples, ...
Nepheline crystallizes upon slow-cooling in some melts concentrated in Na 2 O and Al 2 O 3 , which can result in a residual glass phase of low chemical durability. Nepheline can incorporate many components often found in high-level waste radioactive boro