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Showing 1 to 20 of 53 for “"Mantle Convection"”.
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Characterization of secondary mantle convection from geophysical data and models
Small-scale convection or secondary convection has been studied using the geophysical data and models such as seismic tomography models and geoid anomalies. We used three seismic tomography models, SEMUCB-WM1, SAVANI and S40RTS to infer the lithosphere/asthenosphere boundary, and the …
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Constraints on mantle convection from seismic tomography and flow modeling
… and realistic flow modeling to constrain mantle convection. The bulk of the data used in the tomographic imaging are millions of P, pP and pwP travel time residuals, read from high frequency seismic records. The distribution of earthquakes and stations results in uneven data coverage and …
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Does the theory of parameterized conveciton apply to layered mantle convection?
There are numerous models for convection of the Earth's mantle, the end cases of which are whole-mantle convection and layered convection. Heat flow is an important consideration in the evalution of these models. Simple thermal evolution models based on boundary layer theory have in the past been …
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The Influence of Curvature on Mantle Convection featuring a Temperature-dependent Viscosity
Convection in the silicate mantles or ice layers of terrestrial planets and moons is characterized by a strongly temperature-dependent viscosity. Mantle convection regime is first examined in 2D and 3D spherical geometry with varying mantle curvature (core-to-surface radii-ratio, f) and constant …
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Mantle convection, melt migration and the generation of basalts at mid-ocean ridges
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, and Woods Hole Oceanographic Institute, 1991.
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Effects Of Subduction History On Mantle Convection: Implications For True Polar Wander And Dynamic Topography
… is the subduction of oceanic crust into the mantle along convergent margins; this process of recycling Earth materials destroys the geological data used to reconstruct plate history. To reconcile the long-debated subduction history of the circum-Pacific, this study implements two contrasted …
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The characterization of seismic earth structures and numerical mantle convection experiments using two-point correlation functions
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1995.
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The effect of a shallow low viscosity zone on mantle convection and its expression at the surface of the earth
… a shallow low viscosity layer in the uppermost mantle on mantle flow and its geoid, topography, gravity and heat flow expression is explored. A simple numerical model is employed of convection in a fluid which has a low viscosity layer lying between a rigid bed and a constant viscosity region. …
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The effect of a shallow low viscosity zone on mantle convection and its expression at the surface of the earth
… a shallow low viscosity layer in the uppermost mantle on mantle flow and its geoid, topography, gravity and heat flow expression is explored. A simple numerical model is employed of convection in a fluid which has a low viscosity layer lying between a rigid bed and a constant viscosity region. …
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Geochemical and rheological constraints on the dynamics of the oceanic upper mantle
I provide constraints on mantle convection through observations of the rheology and composition of the oceanic upper mantle. Convection cannot be directly observed, yet is a fundamental part of the plate tectonic cycle. Relative motion among plates is accommodated by localized deformation at their …
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Geochemical and rheological constraints on the dynamics of the oceanic upper mantle
I provide constraints on mantle convection through observations of the rheology and composition of the oceanic upper mantle. Convection cannot be directly observed, yet is a fundamental part of the plate tectonic cycle. Relative motion among plates is accommodated by localized deformation at their …
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Geochemical Implications of Stirring and Mixing in the Earth's Mantle
… the melting, melt migration, and solid state convection that occurs in the Earth's mantle, but to do so requires suitable quantitative models. A new statistical model is introduced to better understand the observed heterogeneity in isotopic ratios 143Nd/144Nd, 87Sr/86Sr, …
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Thermal evolution of a compositionally stratified earth, including plates
… dissipation, which changes the energy balance of mantle convection and influences the thermal history of the Earth. To parameterize these effects, a subduction zone was included in a small region of a finite element model for the mantle, which also features an asthenosphere and a mid-oceanic …
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Understanding late Cenozoic western United States mantle dynamics and surface tectonics using forward-adjoint data assimilation models
Understanding mantle evolution is essential for investigating many processes of the Earth’s surface and interior. A straightforward way to study mantle evolution is through mantle convection simulation. However, a self-consistent and fully dynamic representation of past mantle convection for the …
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Seismic anisotropy and mantle flow beneath Africa and Arabia
… phenomena involve edge-driven small-scale mantle convection and the thermal or dynamic effects of one or more mantle plumes. In this study we use continental scale shear-wave splitting (SWS) measurements to provide additional constraints on the various models of rifting, uplifting, and …
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Mantle Heterogeneity Through Mid-Ocean Ridge Basalts
The chemical heterogeneity of Earth's upper mantle is often examined through mid-ocean ridge basalts (MORB), which contest the prevalent assumption of a well-mixed convecting mantle. This dissertation delves into studying mantle heterogeneity from a local to regional scale. Initially, petrological …
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Low viscosity channels and the stability of long wavelength convection
Mantle convection simulations with a low viscosity channel, akin to the Earth's asthenosphere, are characterized by long wavelength flow structure. Boundary layer theory predicts that as the viscosity of the channel decreases, the wavelength that maximizes heat transfer increases. As a pattern …
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INFERRED RHEOLOGY AND UPPER MANTLE CONDITIONS OF WESTERN NEVADA AND SOUTHERN CALIFORNIA-NORTHWEST MEXICO
… the viscous strength (rheology) of the mantle is essential for understanding the dynamics and evolution of the Earth. Rheology affects many geologic processes such as mantle convection, the earthquake cycle, and plate tectonics. This study uses tectonic (postseismic) and non-tectonic …
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Inside-out diversity of rocky planets
… bare-minimum, dynamic topography due directly to mantle convection, by finding scaling laws of dynamic topography with convective parameters. For increasingly massive planets, topography almost disappears. Smaller ocean basins might suggest flooded worlds, all else equal. Yet large portions of a …
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Mantle thermal evolution of tidally-locked super-earths
… of fixed stellar flux on an Earth-like planet's mantle convection structure and evolution using an axisymmetric finite element fluid convection code, SSAXC. Three punctuating evolutionary steps have been identified. First, a sequence of three initial downwellings form at the antistellar point, …
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