Variations in crustal structure across the transition from West to East Antarctica , Southern Victoria Land

S U M M A R Y The crustal structure beneath Ross Island and the Transantarctic Mountains (TAM) in Southern Victoria Land, Antarctica, is inferred using non-linear inversion of receiver functions, derived from teleseismic earthquake data. Intermediate-period waveforms from more than 160 teleseismic earthquakes recorded between January 1994 and January 2000 were used in the analysis. The inversion results confirm a crustal thickness of 19–21 km beneath Ross Island, consistent with previous multichannel seismic work. In addition we observe a crustal thickness of 18–20 km beneath the Ross Sea coastline immediately adjacent to the TAM. Further inland, beneath the TAM, the estimated Moho depths range from 30–33 km (∼30 km from the coast) to 36–40 km (∼85 km from the coast), deepening away from the coast beneath the TAM. These results are in broad agreement with previous seismic and gravity interpretations. Beneath the TAM a sharp mid-crustal discontinuity is present at 8–14 km depth beneath the eastern-most stations, but absent on the western side of the TAM, indicating a spatial change in the mid-crustal composition.