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On ‘steady‐state’ heat flow and the rheology of oceanic mantle
Author(s) -
Korenaga Jun,
Jordan Thomas H.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016085
Subject(s) - geology , mantle convection , mantle (geology) , rheology , geoid , convection , geophysics , viscosity , mantle plume , thermodynamics , seismology , subduction , physics , lithosphere , tectonics , measured depth
A constraint on the rheology of oceanic mantle is derived on the basis of a recently established scaling law for the onset of convection with temperature‐dependent viscosity. Our approach is free from the assumption of statistically steady‐state convection, which has commonly been employed in previous studies. The estimated range of asthenospheric viscosity is 1–4 × 10 19 Pa s if the activation energy is 300 kJ mol −1 , and 4 × 10 19 – 10 20 Pa s if the activation energy is 100 kJ mol −1 . The former range is consistent with laboratory data as well as geodynamic inference based on the geoid. The latter is consistent with geodynamic inference based on seamount loading history. Different activation energies predict different temperature contrasts in convecting mantle. Seismic tomography has the potential to discriminate between these possibilities.