Lithospheric structure across the Transantarctic Mountains constrained by an analysis of gravity and thermal structure

The Transantarctic Mountains demarcate the boundary between the highly extended lithosphere of the West
Antarctic Rift System and the Proterozoic East Antarctic Craton. Although the last stage of relief development was in
the Eocene, the TAM retain peak elevations in excess of 4500 m. This combination of old age and high relief are
difficult to reconcile, and the mechanism(s) responsible for uplift and support of this mountain range remain elusive and
controversial. Recent seismic studies provide key constraints on the crustal structure. Here we constrain the lithospheric
structure across this boundary by forward modeling of the gravity based on a density structure that reflects the thermal
structure. Our results show that the observed very-long wavelength (>500km) gravity anomaly can be modeled by a
West Antarctic lithosphere ~60 km thick, and an East Antarctic lithosphere ~250 km thick. In addition, the gravity
anomaly associated with the TAM can be modeled by including the thermal effects of heat producing elements
concentrated in the crust.