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 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.

LITHOSPHERE STRUCTURE AND MANTLE DYNAMICS AT THE WESTERN EDGE OF THE LAURENTIAN CRATON

2020 ◽  
Author(s):  
Claire Currie ◽  
◽  
Andrew J. Schaeffer ◽  
Pascal Audet ◽  
Deirdre Mallyon
Keyword(s):  
Mantle Dynamics ◽  
Lithosphere Structure

The Paving Stone Theory of World Tectonics

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Indian Ocean ◽  
Plate Tectonics ◽  
Earth Science ◽  
Transform Faults ◽  
Plate Motions ◽  
Euler’S Theorem ◽  
History Of ◽  
New Ideas ◽  
Entire History ◽  
The Indian Ocean

Tuzo Wilson introduces the concept of transform faults, which has the effect of transforming Earth Science forever. Resistance to the new ideas is finally overcome in the late 1960s, as the theory of moving plates is established. Two scientists play a major role in quantifying the embryonic theory that is eventually dubbed ‘plate tectonics’. Dan McKenzie applies Euler’s theorem, used previously by Teddy Bullard to reconstruct the continents around the Atlantic, to the problem of plate rotations on a sphere and uses it to unravel the entire history of the Indian Ocean. Jason Morgan also wraps plate tectonics around a sphere. Tuzo Wilson introduces the idea of a fixed hotspot beneath Hawaii, an idea taken up by Jason Morgan to create an absolute reference frame for plate motions.

scholarly journals Living benthic foraminiferal assemblages of a transect in the Rockall Trough (NE Atlantic)

2021 ◽  
pp. 103509
Author(s):  
Bianca Lintner ◽  
Michael Lintner ◽  
Patrick Bukenberger ◽  
Ursula Witte ◽  
Petra Heinz
Keyword(s):  
Ne Atlantic ◽  
Rockall Trough
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