scholarly journals Upper Mantle Composition beneath Yakutian Kimberlite Province

2019 ◽  
Keyword(s):  
Upper 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.

Lithospheric domains and controls on kimberlite emplacement, Slave Province, Canada: Evidence from elastic thickness and upper mantle composition

2005 ◽  
Vol 6 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yvette H. Poudjom Djomani ◽  
William L. Griffin ◽  
Suzanne Y. O'Reilly ◽  
Buddy J. Doyle
Keyword(s):  
Upper Mantle ◽  
Mantle Composition ◽  
Slave Province
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