Answers are grounded in this paper and cite their sources.
There are three sets of data (L = wavelength, tr = relaxation time) by using which we can determine the viscosity distribution within the Earth. They are the Fennoscandian uplift, Earth oblateness and a Pleistocene lake uplift. It is shown in the present paper that these are compatible only with a thin viscous channel in the upper mantle. The result seems to preclude lower mantle convection.
No takes yet. Share an insight, caveat, or question.
Takeuchi et al. (1965) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: