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Mantle phase transitions and the free air gravity anomalies over Fennoscandia and Laurentia
Author(s) -
Peltier W. R.,
Wu Patrick
Publication year - 1982
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/gl009i007p00731
Subject(s) - geology , deglaciation , laurentia , mantle (geology) , geophysics , post glacial rebound , mantle convection , lithosphere , paleontology , tectonics , glacial period
The interpretation of free air gravity anomalies over present day centers of postglacial rebound has always been controversial. We show that the observed gravity anomalies over both Fennoscandia and Laurentia and the associated relative sea level variations since deglaciation are explicable with a simple Newtonian viscoelastic model of the earth if the earth model includes the density jumps in the mantle associated with the phase transitions at 420 and 670 km depth. The result has important implications for mantle convection since the observed free air anomalies are very sensitive to the viscosity of the mantle beneath the deepest phase transition.