Excitation of hide waves in the core due to transient-spatially periodic stress in the lower mantle

1973 ◽  
Vol 109 (1) ◽  
pp. 1781-1788
Author(s):  
Rishi Narain Singh
Keyword(s):  
Lower Mantle ◽  
The Core ◽  
Spatially Periodic ◽  
Periodic Stress

Applications of the modified Rydberg–Vinet equation-of-state to the lower mantle and core

2016 ◽  
Vol 30 (04) ◽  
pp. 1650015
Author(s):  
Zheng-Hua Fang
Keyword(s):  
Equation Of State ◽  
Reference Point ◽  
Lower Mantle ◽  
Earth Planet ◽  
The Core ◽  
Fitting Parameters ◽  
Fitting Accuracy

A modified Rydberg–Vinet equation-of-state (mRV EOS) with an arbitrary nonzero-pressure reference point, as is derived strictly from the related Rydberg potential, has been applied to the mantle and the core. The tests and comparisons demonstrate that mRV EOS is superior to the reciprocal [Formula: see text]-primed equation [see F. D. Stacey and P. M. Davis, Phys. Earth Planet. Inter. 142 (2004) 137] not only because of its higher fitting accuracy but also because it has fewer fitting parameters and is easier to use.

scholarly journals Sir Harold Jeffreys, 2 April 1891 - 18 March 1989

1990 ◽  
Vol 36 ◽  
pp. 301-333 ◽  
Keyword(s):  
Small Group ◽  
20Th Century ◽  
Lower Mantle ◽  
Seismic Waves ◽  
Classical Mechanics ◽  
The Core ◽  
New Methods ◽  
The Earth ◽  
Physical Study ◽  
Primitive Condition

Harold Jeffreys stood out among the small group of pioneers who developed the physical study of the Earth from its primitive condition at the beginning of the 20th century to its state at the launch of the first Sputnik . He, above all, applied classical mechanics to investigate the interior of the Earth. He showed that the core of the Earth is liquid and that there is a substantial difference between the upper and lower mantle, as we now call them. His massive analyses of travel times of seismic waves (with K.E. Bullen, F.R.S.) are still standards of reference and are currently being brought up to date. Jeffreys retired from his Chair at Cambridge (but certainly not from active study) just after the first Sputnik had been launched, and as powerful new methods in seismology and marine geophysics were coming into use. Geophysics has since expanded out of all recognition so that it is easy to lose sight of Jeffreys’s earlier contributions. There have been considerable changes in the concepts and methods of geophysics from some that he established, yet the major spherically symmetrical elements of the structure of the Earth that he did so much to elucidate, are the basis for all subsequent elaboration, and generations of students learnt their geophysics from his book The Earth .

Deep carbon cycle and geodynamics: the role of the core and carbonatite melts in the lower mantle

2012 ◽  
Vol 53 (11) ◽  
pp. 1117-1132 ◽  
Author(s):  
N.L. Dobretsov ◽  
A.F. Shatskiy
Keyword(s):  
Carbon Cycle ◽  
Lower Mantle ◽  
The Core

scholarly journals Hydrous SiO2 in subducted oceanic crust and water transport to the core-mantle boundary

2020 ◽  
Author(s):  
Yanhao Lin ◽  
Qingyang Hu ◽  
Jing Yang ◽  
Yue Meng ◽  
Yukai Zhuang ◽  
...  
Keyword(s):  
Partial Melting ◽  
Oceanic Crust ◽  
Lower Mantle ◽  
Oceanic Lithosphere ◽  
Low Velocity ◽  
Water Storage Capacity ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
The Core ◽  
Subducted Oceanic Crust

Abstract Subduction of oceanic lithosphere transports surface water into the mantle where it can have remarkable effects, but how much can be cycled down into the deep mantle, and potentially to the core, remains ambiguous. Recent studies show that dense SiO2 in the form of stishovite, a major phase in subducted oceanic crust at depths greater than ~300 km, has the potential to host and carry water into the lower mantle. We investigate the hydration of stishovite and its higher-pressure polymorphs, CaCl2-type SiO2 and seifertite, in experiments at pressures of 44–152 GPa and temperatures of ~1380–3300 K. We quantify the water storage capacity of these dense SiO2 phases at high pressure and find that water stabilizes CaCl2-type SiO2 to pressures beyond the base of the mantle. We parametrize the P-T dependence of water capacity and model H2O storage in SiO2 along a lower mantle geotherm. Dehydration of slab mantle in cooler slabs in the transition zone can release fluids that hydrate stishovite in oceanic crust. Hydrous SiO2 phases are stable along a geotherm and progressively dehydrate with depth, potentially causing partial melting or silica enrichment in the lower mantle. Oceanic crust can transport ~0.2 wt% water to the core-mantle boundary region where, upon heating, it can initiate partial melting and react with the core to produce iron hydrides, providing plausible explanations for ultra-low velocity regions at the base of the mantle.

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