Rheology of the Upper Mantle: A Synthesis

  title={Rheology of the Upper Mantle: A Synthesis},
  author={Shun‐ichiro Karato and Patrick Wu},
  pages={771 - 778}
Rheological properties of the upper mantle of the Earth play an important role in the dynamics of the lithosphere and asthenosphere. However, such fundamental issues as the dominant mechanisms of flow have not been well resolved. A synthesis of laboratory studies and geophysical and geological observations shows that transitions between diffusion and dislocation creep likely occur in the Earth's upper mantle. The hot and shallow upper mantle flows by dislocation creep, whereas cold and shallow… 

Is the lower‐mantle rheology Newtonian today?

The issue concerning the dominant creep mechanism in mantle convection has been studied numerically with a rheology incorporating both linear and non-linear elements. We have employed a rheology

Rheology of the Upper Mantle and the Mantle Wedge: A View from the Experimentalists

In this manuscript we review experimental constraints for the viscosity of the upper mantle. We first analyze experimental data to provide a critical review of flow law parameters for olivine

Superplasticity in Earth's Lower Mantle: Evidence from Seismic Anisotropy and Rock Physics

In contrast to the upper mantle, the lower mantle of the Earth is elastically nearly isotropic, although its dominant constituent mineral [(Mg,Fe)SiO3 perovskite] is highly anisotropic. On the basis

Can hotter mantle have a larger viscosity

In the diffusion creep regime which is believed to be appropriate for the lower mantle of the Earth, the viscosity of rocks depends on the grain size. The grain size is normally assumed to be

The anisotropic and rheological structure of the oceanic upper mantle from a simple model of plate shear

SUMMARY We have developed a channel flow model that dynamically couples plate motion and mantle stress with a composite rheology (diffusion creep and dislocation creep) to study the rheological and

Numerical models of convection in a rheologically stratified oceanic upper mantle: Early results

Recent seismological evidences imply that the boundary between the lithosphere and asthenosphere is a compositional boundary in the oceanic upper mantle, and a rapid increase of viscosity at this

Viscous and frictional strength of the lithospheric mantle: Microstructural characterization of experimentally deformed polycrystalline Olivine

Convection in Earth’s mantle is the major driving force behind the movement of tectonic plates. While the lower parts of the upper mantle deform in a ductile way, the plates themselves are

Mantle convection: A review




Some geodynamical effects of anisotropic viscosity

Summary. Rheological anisotropy in the mantle may arise from various causes, the most important are the preferred orientation of single crystals, and the orientation of streaks of eclogitic material

Rheology of olivine and the strength of the lithosphere

In order to throw some light on the rheological behavior of the upper mantle of the Earth, a detailed series of high-temperature deformation experiments has been performed on olivine single crystals

On the rheology of the upper mantle

Mechanisms permitting the steady state deformation of crystalline solids are critically reviewed, and an approximate constitutive relationship is derived for fluid phase transport in a partial melt.

Creep laws for the mantle of the Earth

  • J. Weertman
  • Geology
    Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
  • 1978
It is concluded that no large strain, steady-state creep process in mantle rock can account for a Newtonian, constant viscosity mantle and it is suggested that small strain, transient creep and not steady- state creep is involved in the isostatic rebound phenomenon.

Upper mantle seismic anisotropy and lithospheric decoupling

The lithosphere underlying stable continental shield regions is thought to extend to a depth of ∼200 km. Compressional wave velocity models derived from a recent approximately NS refraction profile