Seismic anisotropy in the Slave craton, northern Canada: inferences from a new shear-wave splitting compilation

The Slave craton in northwest Canada is characterized by thick, cold, depleted lithosphere, and its surface geology includes some of the oldest rocks on the planet. In addition, the central Slave has proven economic importance, with a thriving diamond industry fed by suites of Miocene kimberlites. Previous studies of Slave craton architecture and anisotropy suggested a stratified lithosphere within the central Slave, likely associated with craton formation processes and subsequent metasomatism.

Since the original shear-wave splitting studies carried out in the central Slave craton, new seismograph installations have been carried out which permit an expanded view of the architecture of the craton as a whole, as well as its margins. Here we measure (or remeasure) shear wave splitting parameters for the complete dataset, which spans up to three decades for the longest-running stations. This systematic approach allows for a comprehensive comparison of anisotropic parameters across the craton.

Preliminary results suggest that NE-SW fast-polarization orientations dominate the craton at a large scale, though with significant local variability in the central Slave, suggesting lateral variability in lithospheric properties. We look for azimuthal variations in splitting measurements that may indicate stratified anisotropy, and we compare the results with models of azimuthal anisotropy from recent surface wave tomography studies.