New inferences of mantle viscosity from joint inversion of long‐wavelength mantle convection and post‐glacial rebound data

We perform joint inversions for mantle viscosity of geophysical observables associated with both mantle convection and glacial isostatic adjustment (GIA). Our data include coefficients of the non-hydrostatic geoid (up to degree 8) and decay times associated with post-glacial relative sea level (RSL) variations in Hudson Bay and Fennoscandia. We find that both data sets may be reconciled using a single profile of mantle viscosity which is characterized by a significant increase, with depth, across this region. This result weakens previous arguments that the mantle rheology has significant transient effects. The viscosity profiles we obtain are found to reconcile the observed free air gravity anomaly over Hudson Bay.

[1]  J. Mitrovica,et al.  Haskell [1935] revisited , 1996 .

[2]  W. Peltier,et al.  Constraints on mantle viscosity based upon the inversion of post-glacial uplift data from the Hudson Bay region , 1995 .

[3]  A. Dziewoński,et al.  Joint inversions of seismic and geodynamic data for models of three—dimensional mantle heterogeneity , 1994 .

[4]  F. Niu,et al.  Seismic evidence for a 920-km discontinuity in the mantle , 1994, Nature.

[5]  W. Peltier,et al.  Present-day secular variations in the zonal harmonics of earth's geopotential , 1993 .

[6]  Guy Masters,et al.  An inversion for radial viscosity structure using seismic tomography , 1992 .

[7]  W. R. Peltier,et al.  Validation of the ICE‐3G Model of Würm‐Wisconsin Deglaciation using a global data base of relative sea level histories , 1992 .

[8]  R. Peltier,et al.  Viscous flow models of global geophysical observables: 1. Forward problems , 1991 .

[9]  K. Lambeck,et al.  Late Pleistocene and Holocene sea‐level change in the Australian region and mantle rheology , 1989 .

[10]  R. Parker,et al.  Occam's inversion; a practical algorithm for generating smooth models from electromagnetic sounding data , 1987 .

[11]  New constraints on transient lower mantle rheology and internal mantle buoyancy from glacial rebound data , 1985, Nature.

[12]  D. Yuen,et al.  The effects of transient rheology on the interpretation of lower mantle viscosity , 1985 .

[13]  M. Meier.  Contribution of Small Glaciers to Global Sea Level , 1984, Science.

[14]  B. Hager,et al.  Geoid Anomalies in a Dynamic Earth , 1984 .

[15]  B. Hager.  Subducted slabs and the geoid: Constraints on mantle rheology and flow , 1983 .

[16]  N. A. Haskell.  The Motion of a Viscous Fluid Under a Surface Load , 1935 .