Upper Mantle Shear Wave Velocity Structure beneath the Northern Transantarctic Mountains

Abstract: Using data from the Transantarctic Mountains (TAMs) Northern Network, the shear wave velocity structure beneath the northern TAMs was investigated with surface wave tomography. Rayleigh wave phase velocities were calculated using a two-plane wave approximation and were then inverted for shear velocity structure. The resulting model shows a low velocity zone (~4.24 km/s) at ~160 km depth offshore and adjacent to Mt. Melbourne that extends inland and vertically upwards to ~100 km depth beneath the northern TAMs and Victoria Land. Another low velocity zone (~4.16-4.24 km/s) is also seen at ~150 km depth beneath Ross Island, and relatively slow velocities (~4.24-4.32 km/s) along the Terror Rift connect the two low velocity zones. This structure has been interpreted to reflect rift-related decompression melting along the TAMs front, which would provide thermal buoyancy to uplift the mountain range.