Melting of iron–silicon alloy up to the core–mantle boundary pressure: implications to the thermal structure of the Earth’s core

2009 ◽  
Vol 37 (6) ◽  
pp. 353-359 ◽  
Author(s):  
Hidetoshi Asanuma ◽  
Eiji Ohtani ◽  
Takeshi Sakai ◽  
Hidenori Terasaki ◽  
Seiji Kamada ◽  
...  
Keyword(s):  
Thermal Structure ◽  
Earth’S Core ◽  
Earth's Core ◽  
Silicon Alloy ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
Iron Silicon ◽  
The Core

scholarly journals Reflection and transmission of seismic waves under initial stress at the earth's core-mantle boundary

1980 ◽  
Vol 3 (3) ◽  
pp. 591-598
Author(s):  
Sukhendu Dey ◽  
Sushil Kumar Addy
Keyword(s):  
Initial Stress ◽  
Seismic Waves ◽  
Reflection And Transmission Coefficients ◽  
Earth’S Core ◽  
Reflection And Transmission ◽  
Earth's Core ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
Transmission Coefficients ◽  
The Core

In the present paper the influence of the initial stress is shown on the reflection and transmission ofPwaves at the core-mantle boundary. Taking a particular value of the inherent initial stress, the variations of reflection and transmission coefficients with respect to the angle of emergence are represented by graphs. These graphs when compared with those having no initial stress show that the effect of the initial stress is to produce a reflectedPandSwaves with numerically higher amplitudes but a transmittedPwave with smaller amplitude. A method is also indicated in this paper to calculate the actual value of the initial stress near the core-mantle boundary by measuring the amplitudes of incident and reflectedPwaves.

scholarly journals Seismostratigraphy and Thermal Structure of Earth's Core-Mantle Boundary Region

Science ◽  
2007 ◽  
Vol 315 (5820) ◽  
pp. 1813-1817 ◽  
Author(s):  
R. D. van der Hilst ◽  
M. V. de Hoop ◽  
P. Wang ◽  
S.-H. Shim ◽  
P. Ma ◽  
...  
Keyword(s):  
Thermal Structure ◽  
Boundary Region ◽  
Earth’S Core ◽  
Earth's Core ◽  
Mantle Boundary ◽  
Core Mantle Boundary

scholarly journals Origins of ultralow velocity zones through slab-derived metallic melt

2016 ◽  
Vol 113 (20) ◽  
pp. 5547-5551 ◽  
Author(s):  
Jiachao Liu ◽  
Jie Li ◽  
Rostislav Hrubiak ◽  
Jesse S. Smith
Keyword(s):  
Large Scale ◽  
Thermal Structure ◽  
Melting Curve ◽  
Oceanic Lithosphere ◽  
Earth’S Core ◽  
Eutectic Melting ◽  
Earth's Core ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
Metallic Melt

Understanding the ultralow velocity zones (ULVZs) places constraints on the chemical composition and thermal structure of deep Earth and provides critical information on the dynamics of large-scale mantle convection, but their origin has remained enigmatic for decades. Recent studies suggest that metallic iron and carbon are produced in subducted slabs when they sink beyond a depth of 250 km. Here we show that the eutectic melting curve of the iron−carbon system crosses the current geotherm near Earth’s core−mantle boundary, suggesting that dense metallic melt may form in the lowermost mantle. If concentrated into isolated patches, such melt could produce the seismically observed density and velocity features of ULVZs. Depending on the wetting behavior of the metallic melt, the resultant ULVZs may be short-lived domains that are replenished or regenerated through subduction, or long-lasting regions containing both metallic and silicate melts. Slab-derived metallic melt may produce another type of ULVZ that escapes core sequestration by reacting with the mantle to form iron-rich postbridgmanite or ferropericlase. The hypotheses connect peculiar features near Earth's core−mantle boundary to subduction of the oceanic lithosphere through the deep carbon cycle.

scholarly journals Thermal conductivity of Fe-Si alloys and thermal stratification in Earth’s core

2021 ◽  
Vol 119 (1) ◽  
pp. e2119001119
Author(s):  
Youjun Zhang ◽  
Kai Luo ◽  
Mingqiang Hou ◽  
Peter Driscoll ◽  
Nilesh P. Salke ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Transport Properties ◽  
Outer Core ◽  
Earth’S Core ◽  
High Pressure And Temperature ◽  
Earth's Core ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
The Core

Light elements in Earth’s core play a key role in driving convection and influencing geodynamics, both of which are crucial to the geodynamo. However, the thermal transport properties of iron alloys at high-pressure and -temperature conditions remain uncertain. Here we investigate the transport properties of solid hexagonal close-packed and liquid Fe-Si alloys with 4.3 and 9.0 wt % Si at high pressure and temperature using laser-heated diamond anvil cell experiments and first-principles molecular dynamics and dynamical mean field theory calculations. In contrast to the case of Fe, Si impurity scattering gradually dominates the total scattering in Fe-Si alloys with increasing Si concentration, leading to temperature independence of the resistivity and less electron–electron contribution to the conductivity in Fe-9Si. Our results show a thermal conductivity of ∼100 to 110 W⋅m−1⋅K−1 for liquid Fe-9Si near the topmost outer core. If Earth’s core consists of a large amount of silicon (e.g., > 4.3 wt %) with such a high thermal conductivity, a subadiabatic heat flow across the core–mantle boundary is likely, leaving a 400- to 500-km-deep thermally stratified layer below the core–mantle boundary, and challenges proposed thermal convection in Fe-Si liquid outer core.

Hydromagnetic spin-up under conditions of the earth's core-mantle boundary

1978 ◽  
Vol 22 (3) ◽  
pp. 276-282
Author(s):  
Jozef Brestenský ◽  
Gustáv Siráň ◽  
I. Cupal
Keyword(s):  
Earth’S Core ◽  
Earth's Core ◽  
Mantle Boundary ◽  
Core Mantle Boundary
Sign in / Sign up

Export Citation Format

Share Document