Abstract
The Transantarctic Mountains (TAM) represent a major rift margin with enigmatic uplift history. We analyze P-wave receiver functions from 55 broadband seismic stations deployed across the central TAM to constrain crustal thickness (H) and Vp/Vs ratio. Using H-κ stacking and joint inversion of receiver functions with Rayleigh wave dispersion, we obtain robust estimates of crustal properties. Crustal thickness varies from 35 km near the Ross Sea coast to 50 km beneath the highest topography, with an average of 42 km. Vp/Vs ratios range from 1.78 to 1.85, indicative of felsic to intermediate bulk composition. A pervasive mid-crustal discontinuity at ~20 km depth is observed, interpreted as a relict suture zone. Comparison with previous studies reveals lateral heterogeneity consistent with inherited crustal blocks. Our results support a model of crustal thickening by magmatic underplating during Jurassic rifting, followed by flexural isostatic uplift. The mid-crustal feature may correspond to a Paleozoic accretionary boundary. These findings reconcile conflicting uplift models and highlight the role of pre-existing structure in rift margin evolution.
Keywords
receiver functions, Transantarctic Mountains, crustal thickness, Vp/Vs ratio, tectonic evolution, rift margin, Antarctica, crustal structure