Constraints on Lower Mantle Composition fromP-V-TMeasurements of (Fe, Mg)SiO3-Perovskite and (Fe, Mg)O

2013 ◽  
pp. 183-189 ◽  
Author(s):  
R. J. Hemley ◽  
L. Stixrude ◽  
Y. Fei ◽  
H. K. Mao
Keyword(s):  
Lower Mantle ◽  
Mantle Composition

Density and composition of the lower mantle

1989 ◽  
Vol 328 (1599) ◽  
pp. 377-389 ◽  
Keyword(s):  
High Pressure ◽  
Density Distribution ◽  
Upper Mantle ◽  
Lower Mantle ◽  
Mineral Assemblage ◽  
Geophysical Data ◽  
Density Difference ◽  
Depth Range ◽  
Density Measurements ◽  
Mantle Composition

The observed density distribution of the lower mantle is compared with density measurements of the (M g,Fe)SiO 3 perovskite and (Mg,Fe)O magnesiowtistite highpressure phases as functions of pressure, tem perature and composition. We find that for plausible bounds on the composition of the upper mantle (ratio of magnesium to iron + magnesium components x M g ^ 0.88) and the temperature in the lower mantle ( T ^ 2000 K), the high-pressure mineral assemblage of upper-mantle composition is at least 2 .6 ( ± 1 ) % less dense than the lower m antle over the depth range 1000-2000 km. Thus, we find that a model of uniform m antle composition is incompatible with the existing mineralogical and geophysical data. Instead, we expect that the mantle is stratified, with the upper and lower m antle convecting separately, and we estimate that the compositional density difference between these regions is about 5 ( + 2) %. The stratification may not be perfect (‘leaky layering’), but significant intermixing and homogenization of the upper and lower m antle over geological timescales are precluded.

Discriminating lower mantle composition

2020 ◽  
Vol 308 ◽  
pp. 106552
Author(s):  
C. Houser ◽  
J.W. Hernlund ◽  
J. Valencia-Cardona ◽  
R.M. Wentzcovitch
Keyword(s):  
Lower Mantle ◽  
Mantle Composition

scholarly journals Perspective for elasticity of minerals in the Earth's top lower mantle

2020 ◽  
Author(s):  
Zhu Mao ◽  
Ningyu Sun ◽  
Wei Wei
Keyword(s):  
High Pressure ◽  
Lower Mantle ◽  
Seismic Anisotropy ◽  
Theoretical Work ◽  
Low Velocity ◽  
Mantle Composition ◽  
Temperature Conditions ◽  
Recent Advances

Abstract The elasticity of minerals under high pressure-temperature conditions is crucial for constraining mantle composition. This perspective highlights recent advances in experimental and theoretical work in determining the elasticity of minerals to resolve the origin of low-velocity layers and the seismic anisotropy in the top lower mantle.

Reaction between magnesiowusite of lower mantle composition and core-forming Fe-Ni alloy at 1-40 GPa

1997 ◽  
Vol 82 (5-6) ◽  
pp. 526-533 ◽  
Author(s):  
S. Kesson ◽  
A. E. Ringwood ◽  
W. Hibberson ◽  
J. Fitz Gerald ◽  
N. Ware
Keyword(s):  
Lower Mantle ◽  
Mantle Composition ◽  
Ni Alloy
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