scholarly journals Predicting the lithospheric stress field and plate motions by joint modeling of lithosphere and mantle dynamics

2013 ◽  
Vol 118 (1) ◽  
pp. 346-368 ◽  
Author(s):  
A. Ghosh ◽  
W. E. Holt ◽  
L. Wen
Keyword(s):  
Stress Field ◽  
Joint Modeling ◽  
Mantle Dynamics ◽  
Plate Motions ◽  
Lithospheric Stress

scholarly journals Feedbacks between a non-Newtonian upper mantle, mantle viscosity structure and mantle dynamics

2020 ◽  
Vol 224 (2) ◽  
pp. 961-972
Author(s):  
A G Semple ◽  
A Lenardic
Keyword(s):  
Upper Mantle ◽  
Lower Mantle ◽  
Mantle Convection ◽  
Mantle Flow ◽  
Mantle Dynamics ◽  
Plate Motions ◽  
Low Viscosity ◽  
Mantle Viscosity ◽  
Flow Feature ◽  
Mantle Rheology

SUMMARY Previous studies have shown that a low viscosity upper mantle can impact the wavelength of mantle flow and the balance of plate driving to resisting forces. Those studies assumed that mantle viscosity is independent of mantle flow. We explore the potential that mantle flow is not only influenced by viscosity but can also feedback and alter mantle viscosity structure owing to a non-Newtonian upper-mantle rheology. Our results indicate that the average viscosity of the upper mantle, and viscosity variations within it, are affected by the depth to which a non-Newtonian rheology holds. Changes in the wavelength of mantle flow, that occur when upper-mantle viscosity drops below a critical value, alter flow velocities which, in turn, alter mantle viscosity. Those changes also affect flow profiles in the mantle and the degree to which mantle flow drives the motion of a plate analogue above it. Enhanced upper-mantle flow, due to an increasing degree of non-Newtonian behaviour, decreases the ratio of upper- to lower-mantle viscosity. Whole layer mantle convection is maintained but upper- and lower-mantle flow take on different dynamic forms: fast and concentrated upper-mantle flow; slow and diffuse lower-mantle flow. Collectively, mantle viscosity, mantle flow wavelengths, upper- to lower-mantle velocities and the degree to which the mantle can drive plate motions become connected to one another through coupled feedback loops. Under this view of mantle dynamics, depth-variable mantle viscosity is an emergent flow feature that both affects and is affected by the configuration of mantle and plate flow.

scholarly journals Seamounts and oceanic igneous features in the NE Atlantic: a link between plate motions and mantle dynamics

2016 ◽  
Vol 447 (1) ◽  
pp. 419-442 ◽  
Author(s):  
Carmen Gaina ◽  
Anett Blischke ◽  
Wolfram H. Geissler ◽  
Geoffrey S. Kimbell ◽  
Ögmundur Erlendsson
Keyword(s):  
Ne Atlantic ◽  
Mantle Dynamics ◽  
Plate Motions

scholarly journals Effects of upper mantle heterogeneities on lithospheric stress field and dynamic topography

2017 ◽  
Author(s):  
Anthony Osei Tutu ◽  
Bernhard Steinberger ◽  
Stephan V. Sobolev ◽  
Irina Rogozhina ◽  
Anton A. Popov
Keyword(s):  
Heat Flow ◽  
Stress Field ◽  
Upper Mantle ◽  
Western Europe ◽  
Thermal Structure ◽  
Mantle Flow ◽  
Density Structure ◽  
Dynamic Topography ◽  
S Wave ◽  
Lithospheric Stress

Abstract. The orientation and tectonic regime of the observed crustal/lithospheric stress field contribute to our knowledge of different deformation processes occurring within the Earth's crust and lithosphere. In this study, we analyze the influence of the thermal and density structure of the upper mantle on the lithospheric stress field and topography. We use a 3D lithosphere-asthenosphere numerical model with power-law rheology, coupled to a spectral mantle flow code at 300 km depth. Our results are validated against the World Stress Map 2016 and the observation-based residual topography. We derive the upper mantle thermal structure from either a heat flow model combined with a sea floor age model (TM1) or a global S-wave velocity model (TM2). We show that lateral density heterogeneities in the upper 300 km have a limited influence on the modeled horizontal stress field as opposed to the resulting dynamic topography that appears more sensitive to such heterogeneities. There is hardly any difference between the stress orientation patterns predicted with and without consideration of the heterogeneities in the upper mantle density structure across North America, Australia, and North Africa. In contrast, we find that the dynamic topography is to a greater extent controlled by the upper mantle density structure. After correction for the chemical depletion of continents, the TM2 model leads to a much better fit with the observed residual topography giving a correlation of 0.51 in continents, but this correction leads to no significant improvement in the resulting lithosphere stresses. In continental regions with abundant heat flow data such as, for instant, Western Europe, TM1 results in relatively a small angular misfits of 18.30° between the modeled and observation-based stress field compared 19.90° resulting from modeled lithosphere stress with s-wave based model TM2.

scholarly journals Origin of the lithospheric stress field

2004 ◽  
Vol 109 (B1) ◽  
Author(s):  
Carolina Lithgow-Bertelloni ◽  
Jerome H. Guynn
Keyword(s):  
Stress Field ◽  
Lithospheric Stress

scholarly journals Effects of upper mantle heterogeneities on the lithospheric stress field and dynamic topography

Solid Earth ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 649-668 ◽  
Author(s):  
Anthony Osei Tutu ◽  
Bernhard Steinberger ◽  
Stephan V. Sobolev ◽  
Irina Rogozhina ◽  
Anton A. Popov
Keyword(s):  
Heat Flow ◽  
Stress Field ◽  
Upper Mantle ◽  
Thermal Structure ◽  
Mantle Flow ◽  
Density Structure ◽  
Dynamic Topography ◽  
S Wave ◽  
Mantle Heterogeneities ◽  
Lithospheric Stress

Abstract. The orientation and tectonic regime of the observed crustal/lithospheric stress field contribute to our knowledge of different deformation processes occurring within the Earth's crust and lithosphere. In this study, we analyze the influence of the thermal and density structure of the upper mantle on the lithospheric stress field and topography. We use a 3-D lithosphere–asthenosphere numerical model with power-law rheology, coupled to a spectral mantle flow code at 300 km depth. Our results are validated against the World Stress Map 2016 (WSM2016) and the observation-based residual topography. We derive the upper mantle thermal structure from either a heat flow model combined with a seafloor age model (TM1) or a global S-wave velocity model (TM2). We show that lateral density heterogeneities in the upper 300 km have a limited influence on the modeled horizontal stress field as opposed to the resulting dynamic topography that appears more sensitive to such heterogeneities. The modeled stress field directions, using only the mantle heterogeneities below 300 km, are not perturbed much when the effects of lithosphere and crust above 300 km are added. In contrast, modeled stress magnitudes and dynamic topography are to a greater extent controlled by the upper mantle density structure. After correction for the chemical depletion of continents, the TM2 model leads to a much better fit with the observed residual topography giving a good correlation of 0.51 in continents, but this correction leads to no significant improvement of the fit between the WSM2016 and the resulting lithosphere stresses. In continental regions with abundant heat flow data, TM1 results in relatively small angular misfits. For example, in western Europe the misfit between the modeled and observation-based stress is 18.3°. Our findings emphasize that the relative contributions coming from shallow and deep mantle dynamic forces are quite different for the lithospheric stress field and dynamic topography.

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