Melting of the Earth’s inner core

@article{Gubbins2011MeltingOT,
  title={Melting of the Earth’s inner core},
  author={D. Gubbins and B. Sreenivasan and J. Mound and S. Rost},
  journal={Nature},
  year={2011},
  volume={473},
  pages={361-363}
}
The Earth’s magnetic field is generated by a dynamo in the liquid iron core, which convects in response to cooling of the overlying rocky mantle. The core freezes from the innermost surface outward, growing the solid inner core and releasing light elements that drive compositional convection. Mantle convection extracts heat from the core at a rate that has enormous lateral variations. Here we use geodynamo simulations to show that these variations are transferred to the inner-core boundary and… Expand
View on Nature
people.virginia.edu
107 Citations
Highly Influential Citations
5
Background Citations
17
Methods Citations
4
Results Citations
2

107 Citations

Citation Type

Citation Type

On mantle-induced heat flow variations at the inner core boundary
Abstract Seismic shear wave velocity variations in the Earth’s lower mantle have led to the inference that fluid motion in the core can be controlled by the mantle. Non-axisymmetric features of the… Expand
Thermal convection in Earth's inner core with phase change at its boundary
Inner core translation, with solidification on one hemisphere and melting on the other, provides a promising basis for understanding the hemispherical dichotomy of the inner core, as well as the… Expand
Regional stratification at the top of Earth's core due to core–mantle boundary heat flux variations
Earth’s magnetic field is generated by turbulent motion in its fluid outer core. Although the bulk of the outer core is vigorously convecting and well mixed, some seismic, geomagnetic and geodynamic… Expand
Earth science: A deep foundry
TLDR
Geodynamo simulations showing that variations in heat flow at the core–mantle boundary are transferred to the inner core boundary are presented, finding that the variations can be large enough to cause heat to flow into the inner cores and, if this were to occur in the Earth, to cause localized melting. Expand
Ancient dynamos of terrestrial planets more sensitive to core-mantle boundary heat flows
Abstract The early dynamos of Earth and Mars probably operated without an inner core being present. They were thus exclusively driven by secular cooling and radiogenic heating, whereas the present… Expand
Response of Earth's magnetic field to large lower mantle heterogeneity
Abstract A simplified two-fold pattern of convection in the Earth's core is often used to explain the non-axisymmetric magnetic flux concentrations in the present day geomagnetic field. For large… Expand
Melting of Iron at Earth’s Inner Core Boundary Based on Fast X-ray Diffraction
Hot Enough to Melt Iron Earth's core is divided into a fluid outer core and a solid inner core, both composed predominately of iron at extremely high pressures and temperatures. The boundary between… Expand
Earth’s solid inner core: Seismic implications of freezing and melting
Seismic P velocity structure is determined for the upper 500 km of the inner core and lowermost 200 km of the outer core from differential travel times and amplitude ratios. Results confirm the… Expand
Mantle-induced temperature anomalies do not reach the inner core boundary
Temperature anomalies in Earth’s liquid core reflect the vigour of convection and the nature and extent of thermal core–mantle coupling. Numerical simulations suggest that longitudinal temperature… Expand
Bottom-up control of geomagnetic secular variation by the Earth’s inner core
TLDR
To match the observed pattern of geomagnetic secular variation, the solid material forming the inner core must now be in a state of differential growth rather than one of growth and melting induced by convective translation. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 34 REFERENCES
Thermochemical flows couple the Earth's inner core growth to mantle heterogeneity
TLDR
It is shown that a single model of thermochemical convection and dynamo action can account for all these effects by producing a large-scale, long-term outer core flow that couples the heterogeneity of the inner core with that of the lower mantle. Expand
Melting-induced stratification above the Earth’s inner core due to convective translation
TLDR
It is shown that this layer can be generated by simultaneous crystallization and melting at the surface of the Earth’s inner core, and that a translational mode of thermal convection in the inner core can produce enough melting and crystallization on each hemisphere respectively for the dense layer to develop. Expand
The role of the Earth's mantle in controlling the frequency of geomagnetic reversals
A series of computer simulations of the Earth's dynamo illustrates how the thermal structure of the lowermost mantle might affect convection and magnetic-field generation in the fluid core. Eight… Expand
Correlation of Earth’s magnetic field with lower mantle thermal and seismic structure
Abstract Variations in the Earth’s lower mantle appear to influence the geodynamo operating in the liquid core. We present a solution to the full dynamo equations with lateral variations in heat flux… Expand
On the cooling of the Earth's core.
Abstract We have constructed a self-consistent model for cooling of the Earth's core in which the thermal history of the core is computed as a function of the time evolution of the heat flux… Expand
Dynamos with weakly convecting outer layers: implications for core-mantle boundary interaction
Convection in the Earth's core is driven much harder at the bottom than the top. This is partly because the adiabatic gradient steepens towards the top, partly because the spherical geometry means… Expand
Lopsided Growth of Earth's Inner Core
TLDR
It is proposed that the growth of the solid core implies an eastward drift of the material, driven by crystallization in the Western Hemisphere and melting in the Eastern Hemisphere, which generates an asymmetric distribution of sizes of iron crystals, which grow during their translation. Expand
A thermochemical boundary layer at the base of Earth's outer core and independent estimate of core heat flux
SUMMARY Recent seismological observations suggest the existence of a ≈150-km-thick density-stratified layer with a P-wave velocity gradient that differs slightly from PREM. Such a structure can only… Expand
Convection in the Earth’s core driven by lateral variations in the core–mantle boundary heat flux
Moving core fluid maintains an isothermal core-mantle boundary (CMB), so lateral variations in the CMB heat flow result from mantle convection. Such variations will drive thermal winds, even if the… Expand
Gross thermodynamics of two-component core convection
We model the inner core by an alloy of iron and 8 per cent sulphur or silicon and the outer core by the same mix with an additional 8 per cent oxygen. This composition matches the densities of… Expand
...
1
2
3
4
...