Abstract
Seismic anisotropy provides insight into past episodes of lithospheric
deformation and the orientations of strain in the underlying
asthenosphere. The Greenland mantle has played host to a rich history of
tectonic processes, including multiple orogenies and plume-lithosphere
interactions. This study presents new measurements of SKS splitting that
reveal strong variations in fast polarization direction with
back-azimuth that are consistent across Greenland, including at stations
where splitting measurements have not previously been reported. We
compared observed fast polarization directions to the predictions of
two-layer models with olivine-orthopyroxene anisotropy. The family of
models which provides acceptable misfits at 95% confidence indicates an
upper layer olivine a-axis azimuth of 226 +/- 2.9{degree sign} and a
lower layer olivine a-axis azimuth of 124 +/- 2.7{degree sign} and
non-zero axis dips are required. These models are consistent with
asthenospheric anisotropy aligned approximately parallel to the
direction of plate motion and lithospheric anisotropy due to Proterozoic
and Archean orogenic fabrics.