New constraints on the upper mantle structure of the Slave craton from Rayleigh wave inversion

摘要: [1] Rayleigh wave phase and amplitude data are analyzed to provide new insight into the velocity structure of upper mantle beneath Slave craton, in northwestern Canadian Shield. We invert for velocities at periods between 20 s–142 s (with greatest sensitivity depths 28–200 km) using crossing ray paths from events recorded by POLARIS broadband seismic network Yellowknife array. Phase obtained province comparable those other cratons shorter periods, but exceed global average ∼2% above 60 s, suggesting that craton may be an end member terms its high degree depletion. The one-dimensional inversion yields upper-mantle S-wave 4.7 ± 0.2 km/s persist 220 65 km depth thus define cratonic lithosphere. Azimuthal anisotropy is well resolved all with a dominant fast direction N59°E 20°, influenced both lithospheric fabric sub-lithospheric flow.