Antarctic upper mantle rheology
Open Access
- 17 November 2021
- journal article
- Published by Geological Society of London in Geological Society, London, Memoirs
- Vol. 56 (1), 267-294
- https://doi.org/10.1144/m56-2020-19
Abstract
The Antarctic mantle and lithosphere are known to have large lateral contrasts in seismic velocity and tectonic history. These contrasts suggest differences in the response timescale of mantle flow across the continent, similar to those documented between the northeastern and southwestern upper mantle of North America. Glacial isostatic adjustment and geodynamical modelling rely on independent estimates of lateral variability in effective viscosity. Recent improvements in imaging techniques and the distribution of seismic stations now allow resolution of both lateral and vertical variability of seismic velocity, making detailed inferences about lateral viscosity variations possible. Geodetic and palaeosea-level investigations of Antarctica provide quantitative ways of independently assessing the 3D mantle viscosity structure. While observational and causal connections between inferred lateral viscosity variability and seismic velocity changes are qualitatively reconciled, significant improvements in the quantitative relations between effective viscosity anomalies and those imaged by P- and S-wave tomography have remained elusive. Here we describe several methods for estimating effective viscosity from S-wave velocity. We then present and compare maps of the viscosity variability beneath Antarctica based on the recent S-wave velocity model ANT-20 using three different approaches.Keywords
Funding Information
- National Aeronautics and Space Administration (NNH13ZDA001N-SLR)
- National Aeronautics and Space Administration (NNH19ZDA001N-GRACEFO)
- National Aeronautics and Space Administration (NNH16ZDA001N-SLCT)
- National Aeronautics and Space Administration (NNH15ZDA001N-ESI)
- National Aeronautics and Space Administration (NNH13ZDA001N-SLR)
- National Aeronautics and Space Administration (NNH19ZDA001N-GRACEFO)
- National Aeronautics and Space Administration (NNH16ZDA001N-SLCT)
- National Aeronautics and Space Administration (NNH15ZDA001N-ESI)
This publication has 180 references indexed in Scilit:
- An investigation of Glacial Isostatic Adjustment over the Amundsen Sea sector, West AntarcticaGlobal and Planetary Change, 2012
- Shallow upper mantle rheology and secular ice sheet fluctuationsTectonophysics, 2011
- Thermodynamics of the Earth's MantleReviews in Mineralogy and Geochemistry, 2010
- Structure of the upper mantle under the Antarctic Plate from surface wave tomographyGeophysical Research Letters, 2001
- Rock deformation tests to large shear strains in torsionJournal of Structural Geology, 2000
- Thermal-mechanical effects of low-temperature plasticity (the Peierls mechanism) on the deformation of a viscoelastic shear zoneEarth and Planetary Science Letters, 1999
- Low‐frequency shear attenuation in polycrystalline olivine: Grain boundary diffusion and the physical significance of the Andrade model for viscoelastic rheologyJournal of Geophysical Research, 1998
- Transient creep in natural and synthetic, iron-bearing olivine single crystals: Mechanical results and dislocation microstructuresTectonophysics, 1994
- A seismic equation of state II. Shear properties and thermodynamics of the lower mantlePhysics of the Earth and Planetary Interiors, 1987
- Shear modulus and Q of forsterite and dunite near partial melting from forced-oscillation experimentsPhysics of the Earth and Planetary Interiors, 1982