Uplift and erosion of an intraforeland topographic high: implication for the evolution of the Gondwanian Transantarctic foreland

The Transantarctic Basin is a continental basin system developed for ca 200 Myr, from the Devonian to the Early Jurassic, along the Panthalassa margin of Gondwana and above the peneplained Ross Orogeny rocks. The Beacon Supergroup strata form the clastic sedimentary infill of the Transantarctic Basin.

Geodynamic interpretation of the Transantarctic Basin is not univocal and likely geodynamic conditions accounting for basin subsidence have been changed in space and time. Involvement of the basin into the Gondwanian orogenic deformation is a key question for defining the geodynamic setting and the tectonic environment during the Beacon Supergroup deposition. Nonetheless, involvement of  Beacon Supergroup  in orogenic shortening is  poorly assessed for the limited exposed rocks and because formation of the Cenozoic  Transantarctic rift shoulder modified the Paleozoic geometry of the Beacon strata.

Here we explored the exhumation pattern and thermal evolution of the basement rocks and the immediately overlain Beacon sandstones through low-temperature apatite fission track and (U-Th)/He zircon thermochronology along the Prince Albert Mts, where Beacon deposits are particularly thin to suppose a relevant erosional event during the Paleozoic. Thermochronological data and thermal modelling pointed out that basement rocks and Beacon sandstones of the Prince Albert Mts have preserved evidence of a Late Paleozoic erosional event that allows to infer an actively eroding topographic high that lasted from Early to Late Paleozoic times, as a consequence of the far-field stress transmitted from the active Gondwanian convergent margin.