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Consequences of experimental transient rheology
Author(s) -
Sabadini Roberto,
Smith Brad K.,
Yuen David A.
Publication year - 1987
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/gl014i008p00816
Subject(s) - rheology , geoid , geology , viscosity , discontinuity (linguistics) , transient (computer programming) , geophysics , creep , mechanics , mantle (geology) , physics , thermodynamics , mathematics , mathematical analysis , computer science , operating system , measured depth
Recent analyses of transient creep data for lower crustal and upper mantle substances show that the parameters of the Burgers’ body rheological model, used up to now by geodynamicists, have much lower ratios of the short‐term to long‐term viscosities than the laboratory values. We have used these data to constrain the viscosity contrast across the 670 km discontinuity. Our results show that the previously inferred viscosity variations are now reduced by about a factor of ten in the new transient models. This finding is in agreement with the revised viscosity estimate based on long‐wavelength geoid anomalies and seismic tomography. We find that time‐dependent perturbations to the gravity field from recent ice movements are not at all small.