Crustal structure of the Gamburtsev Mountains, East Antarctica, from S-wave receiver functions and Rayleigh wave phase velocities

The Gamburtsev Subglacial Mountains (GSM), located in central East Antarctica, are one of the most enigmatic tectonic features on Earth. Buried beneath several kilometers of ice, the mountains are characterized by peak elevations reaching ~. 3000. m above sea level. In this study, new data from the Gamburtsev Antarctic Mountains Seismic Experiment (GAMSEIS) are presented, which substantially improve constraints on the crustal and upper mantle structure in this region. S-wave receiver functions and Rayleigh wave phase velocities are used to analyze data from the GAMSEIS deployment and to improve estimates of crustal thickness beneath the East Antarctic craton and the GSM. Our results indicate that the cratonic crust surrounding the GSM is ~. 40-45. km thick. Beneath the GSM, the crust thickens to ~. 55-58. km and provides isostatic support for the high mountain elevations. It has been suggested that thicker crust beneath the GSM may reflect magmatic underplating associated with a mantle plume. However, considering our results with those from other previous and ongoing studies, we instead favor models in which the GSM are an old continental feature associated with either Proterozoic or Paleozoic tectonic events.