Variations in Earth's 1D viscosity structure in different tectonic regimes

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Authors

Anthony Osei Tutu , Christopher Harig

Abstract

Past estimates of Earth’s mantle viscosity profile using the long-wavelength geoid suggest an increase in viscosity from the upper to lower mantle of roughly 2-3 orders of magnitude. We use a spatio-spectral localization technique with the geoid to estimate a series of locally constrained viscosity profiles covering two unique regions, the Pacific and Atlantic hemispheres. The Pacific region exhibits the conventional Earth's 1D rheology with a factor of roughly 80-100 increase in viscosity occurring at transition zone depths. The Atlantic region in contrast does not show significant viscosity jumps with depth, and instead has a near uniform viscosity in the top 1000 km. Our inferred viscosity variations between the two regions could be due to the prevalence of present-day subduction in the Pacific region and the relative infrequence of slabs in the Atlantic, combined with a possible hydrated transition zone and mid-mantle in the Atlantic region by ancient subduction.

DOI

https://doi.org/10.31223/X5WG9Q

Subjects

Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Keywords

Mantle viscosity | spatiospectral localization | geoid | subduction

Dates

Published: 2022-01-14 06:31

Last Updated: 2022-06-02 13:50

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License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
The authors declare no conflict of interest

Data Availability (Reason not available):
code will be provided our Github accounts

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