Upper mantle anisotropy from teleseismic SKS splitting beneath Lützow-Holm Bay Region, East Antarctica

Investigations of SKS wave splitting of teleseismic events from digital seismographs recorded at eight stations
around the Lützow-Holm Bay Region have lead to understanding the evolution of the Antarctic Plate. The observed delay
times of SKS splitting are up to 1.3 s, which are generally equal to the global average. A two-layer model reveals that the
lower layer anisotropy is caused by the recent asthenospheric flow, as compared with the Absolute Plate Motion by the
HS3-NUVEL1 model. The upper layer anisotropy corresponds well to polarization of NE–SW convergence direction
between East and West Gondwana in Pan-African age. We suggest that the upper layer anisotropy was formed during
Pan-African orogeny and was possibly influenced by the preexisting structure during Gondwana break-up. The origin of
anisotropy is the Lattice Preferred Orientation of olivine which was caused by both paleo-tectonic events and the recent
asthenospheric flow.