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A dynamic model of Venus's gravity field
Author(s) -
Kiefer Walter S.,
Richards Mark A.,
Hager Bradford H.,
Bills Bruce G.
Publication year - 1986
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/gl013i001p00014
Subject(s) - mantle convection , venus , mantle (geology) , geophysics , geology , geoid , asthenosphere , mantle wedge , gravity anomaly , ocean surface topography , lithosphere , geodesy , astrobiology , physics , tectonics , seismology , paleontology , oil field , measured depth
Unlike on Earth, long‐wavelength gravity anomalies and topography correlate well on Venus. Venus's admittance curve from spherical harmonic degree 2 to 18 is inconsistent with either Airy or Pratt isostasy but is consistent with dynamic support from mantle convection. A model using whole mantle flow and a high viscosity near‐surface layer overlying a constant viscosity mantle reproduces this admittance curve. On Earth, the effective viscosity deduced from geoid modeling increases by a factor of 300 from the asthenosphere to the lower mantle. These viscosity estimates may be biased by neglect of lateral variations in mantle viscosity. The different effective viscosity profiles for Earth and Venus may reflect their convective styles, with tectonism and mantle heat transport dominated by hot plumes on Venus and by subducted slabs on Earth.