Journal ArticleDOI
Dynamical influences from thermal‐chemical instabilities at the core‐mantle boundary
Ulrich Hansen,David A. Yuen +1 more
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In this article, two-dimensional, time-dependent calculations show that the thermal and flow structures can be influenced by lower-mantle thermal-chemical instabilities, and that the amplitude of CMB hills is reduced greatly from the depth-dependent of thermal expansivity, found in recent high-pressure experiments.Abstract:
Two-dimensional, time-dependent calculations show that the thermal and flow structures can be influenced by the lower-mantle thermal-chemical instabilities. The style of the core-mantle boundary (CMB) deformation in thermal-chemical convection is different from that obtained in thermal convection. The amplitude of CMB hills is reduced greatly from the depth-dependence of thermal expansivity, found in recent high-pressure experiments.read more
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Journal ArticleDOI
Compositional stratification in the deep mantle
TL;DR: A boundary between compositionally distinct regions at a depth of about 1600 kilometers may explain the seismological observations pertaining to Earth's lower mantle, produce the isotopic signatures of mid-ocean ridge basalts and oceanic island basalts, and reconcile the discrepancy between the observed heat flux and the heat production of the mid-Ocean ridge basalt source region.
Journal ArticleDOI
Segregation of subducted oceanic crust in the convecting mantle
TL;DR: In this paper, the authors study both the geodynamical and geochemical aspects of this hypothesis in two-dimensional numerical convection models, in which plate motion is imposed by a velocity boundary condition.
Journal ArticleDOI
Compositional heterogeneity in the bottom 1000 kilometers of earth's mantle : Toward a hybrid convection model
TL;DR: A range of geophysical evidence indicates that compositionally distinct mantle domains may exist in the bottom 1000 kilometers of the mantle, which implies that mantle convection is more complex than envisaged by conventional end-member flow models.
Journal ArticleDOI
Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures
Elise Knittle,Raymond Jeanloz +1 more
TL;DR: The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 kilometers of Earth's mantle, the D" layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy ofEarth's core.
Book ChapterDOI
Three‐Dimensional Simulations of Mantle Convection with a Thermo‐Chemical Basal Boundary Layer: D″?
TL;DR: In this paper, numerical simulations in both two and three-dimensions are performed to investigate the hypothesis that D is a thermo-chemical boundary layer, and the authors show that the layer forms a spoke pattern with entrainment in upwelling cylinders, even for systems which are heated entirely from within.
References
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Journal ArticleDOI
Large-scale mantle convection and the aggregation and dispersal of supercontinents
TL;DR: In this article, the first time-dependent numerical simulations of continental aggregation and dispersal demonstrate a dynamic feedback between the motion of continental plates and mantle convection, which is in agreement with the present geophysical state of the mantle and the geological record over the last 200 million years.
Journal ArticleDOI
Topography of the core–mantle boundary and lateral homogeneity of the liquid core
TL;DR: In this article, separate inversions of travel-time residuals of waves reflected from and transmitted through the core-mantle boundary yield similar results in terms of spherical harmonic expansion of its topography up to degree and order 4.
Journal ArticleDOI
Convection in a compressible fluid with infinite Prandtl number
Gary T. Jarvis,Dan McKenzie +1 more
TL;DR: In this article, an approximate set of equations is derived for a compressible liquid of infinite Prandtl number, referred to as the anelastic liquid equations, which are solved in two dimensions and a systematic investigation of compressible convection is presented in which d/HT is varied from 0·1 to 1·5.
Journal ArticleDOI
Surface deformation, gravity anomalies and convection
TL;DR: In this paper, the long-wavelength gravity and residual depth anomalies in the North Atlantic and Pacific Oceans resemble those obtained from numerical experiments on convective flow, and the ratio of these anomalies, 2, is obtained as a function of wavelength for a variety of simple two-dimensional convective flows.
Journal ArticleDOI
Plume formation in the D-double prime-layer and the roughness of the core-mantle boundary
TL;DR: In this paper, a series of very high-resolution finite element calculations of plume formation in the D-double prime-layer has been performed for several plausible rheologies and boundary conditions in order to study both the early and later stages of boundary layer development.
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Segregation of subducted oceanic crust in the convecting mantle
Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures
Elise Knittle,Raymond Jeanloz +1 more