scholarly journals Fe3+and Al solubilities in MgSiO3perovskite: implication of the Fe3+AlO3substitution in MgSiO3perovskite at the lower mantle condition

2005 ◽  
Vol 32 (16) ◽  
Author(s):  
Daisuke Nishio-Hamane
Keyword(s):  
Lower Mantle ◽  
Mantle Condition

scholarly journals Density functional theory calculations and thermodynamic analysis of bridgmanite surface structure

2019 ◽  
Vol 21 (3) ◽  
pp. 1009-1013 ◽  
Author(s):  
Ming Geng ◽  
Hannes Jónsson
Keyword(s):  
Density Functional Theory ◽  
Surface Structure ◽  
Thermodynamic Analysis ◽  
Lower Mantle ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Chemical Potentials ◽  
Mantle Condition

Bridgmanite surface structure variations as a function of chemical potentials of Mg and O at the upper most of the Earth's lower mantle condition (∼660 km).

Stabilities of SiO2stishovite and CaSiO3perovskite under lower mantle condition

1990 ◽  
Vol 5 (1-6) ◽  
pp. 699-701 ◽  
Author(s):  
T. Yagi ◽  
Y. Tsuchida ◽  
S. Kusanagi ◽  
Y. Fukai
Keyword(s):  
Lower Mantle ◽  
Mantle Condition

PRESSURE-RELATED PHASE STABILITY OF MgSiO3and(Mg0.75, Fe0.25)SiO3 AT LOWER MANTLE CONDITION

2009 ◽  
Vol 23 (16) ◽  
pp. 3323-3329
Author(s):  
LI-WEI DENG ◽  
JI-JUN ZHAO ◽  
HONG LIU ◽  
DI WU ◽  
ZI-ZHENG GONG
Keyword(s):  
Equation Of State ◽  
Phase Stability ◽  
First Principles ◽  
Relative Stability ◽  
Lower Mantle ◽  
Relative Phase ◽  
Orthorhombic Phase ◽  
Pbnm Space Group ◽  
Mantle Condition ◽  
Related Phase

Relative stability of different phases for MgSiO 3 and ( Mg 0.75, Fe 0.25) SiO 3 within 0–110 GPa are investigated using first-principles method. For MgSiO 3, the computed equation of state for orthorhombic phase of Pbnm space group agrees well with experimental results. The relative stability reduces from observed Pbnm orthorhombic phase to intermediated tetragonal P4mbm phase, and then to hypothetical cubic [Formula: see text] phase. For ( Mg 0.75, Fe 0.25) SiO 3, the same sequence of relative phase stability is observed. Thus, the low-symmetric orthorhombic MgSiO 3 should be favored in the lower mantle condition, while adding Fe into MgSiO 3 will make it less stable at the same depth.

scholarly journals Feedbacks between a non-Newtonian upper mantle, mantle viscosity structure and mantle dynamics

2020 ◽  
Vol 224 (2) ◽  
pp. 961-972
Author(s):  
A G Semple ◽  
A Lenardic
Keyword(s):  
Upper Mantle ◽  
Lower Mantle ◽  
Mantle Convection ◽  
Mantle Flow ◽  
Mantle Dynamics ◽  
Plate Motions ◽  
Low Viscosity ◽  
Mantle Viscosity ◽  
Flow Feature ◽  
Mantle Rheology

SUMMARY Previous studies have shown that a low viscosity upper mantle can impact the wavelength of mantle flow and the balance of plate driving to resisting forces. Those studies assumed that mantle viscosity is independent of mantle flow. We explore the potential that mantle flow is not only influenced by viscosity but can also feedback and alter mantle viscosity structure owing to a non-Newtonian upper-mantle rheology. Our results indicate that the average viscosity of the upper mantle, and viscosity variations within it, are affected by the depth to which a non-Newtonian rheology holds. Changes in the wavelength of mantle flow, that occur when upper-mantle viscosity drops below a critical value, alter flow velocities which, in turn, alter mantle viscosity. Those changes also affect flow profiles in the mantle and the degree to which mantle flow drives the motion of a plate analogue above it. Enhanced upper-mantle flow, due to an increasing degree of non-Newtonian behaviour, decreases the ratio of upper- to lower-mantle viscosity. Whole layer mantle convection is maintained but upper- and lower-mantle flow take on different dynamic forms: fast and concentrated upper-mantle flow; slow and diffuse lower-mantle flow. Collectively, mantle viscosity, mantle flow wavelengths, upper- to lower-mantle velocities and the degree to which the mantle can drive plate motions become connected to one another through coupled feedback loops. Under this view of mantle dynamics, depth-variable mantle viscosity is an emergent flow feature that both affects and is affected by the configuration of mantle and plate flow.

The Dupal anomaly as a trace of the upwelling lower mantle

Nature ◽  
1988 ◽  
Vol 336 (6200) ◽  
pp. 667-670 ◽  
Author(s):  
Pat Castillo
Keyword(s):  
Lower Mantle

scholarly journals From Slater to Mott physics by epitaxially engineering electronic correlations in oxide interfaces

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Carla Lupo ◽  
Evan Sheridan ◽  
Edoardo Fertitta ◽  
David Dubbink ◽  
Chris J. Pickard ◽  
...  
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Charge Transfer ◽  
Lower Mantle ◽  
Random Structure ◽  
Titanium Oxides ◽  
Oxide Interfaces ◽  
Electronic Correlations ◽  
Epitaxial Strain ◽  
Magnetic Switching

AbstractUsing spin-assisted ab initio random structure searches, we explore an exhaustive quantum phase diagram of archetypal interfaced Mott insulators, i.e. lanthanum-iron and lanthanum-titanium oxides. In particular, we report that the charge transfer induced by the interfacial electronic reconstruction stabilises a high-spin ferrous Fe2+ state. We provide a pathway to control the strength of correlation in this electronic state by tuning the epitaxial strain, yielding a manifold of quantum electronic phases, i.e. Mott-Hubbard, charge transfer and Slater insulating states. Furthermore, we report that the electronic correlations are closely related to the structural oxygen octahedral rotations, whose control is able to stabilise the low-spin state of Fe2+ at low pressure previously observed only under the extreme high pressure conditions in the Earth’s lower mantle. Thus, we provide avenues for magnetic switching via THz radiations which have crucial implications for next generation of spintronics technologies.

Formation of Mg-Orthocarbonate through the Reaction MgCO3 + MgO = Mg2CO4 at Earth’s Lower Mantle P–T Conditions

2021 ◽  
Author(s):  
Pavel N. Gavryushkin ◽  
Dinara N. Sagatova ◽  
Nursultan Sagatov ◽  
Konstantin D. Litasov
Keyword(s):  
Lower Mantle
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