Thermochronologic constraints on Jurassic rift flank denudation in the Thiel Mountains, Antarctica

The Thiel Mountains are part of the Transantarctic Mountains (TAM) and occupy a strategic position close
to the East-West Antarctic boundary. They occur in a region of relatively subdued topography distal from high
topography and high relief of most of the TAM adjacent to the West Antarctic rift system. Low-temperature
thermochronology on samples collected from the Reed Ridge granite on the north flank of the Thiel Mountains
constrain the thermal and hence tectonic history. Apatite fission track data plus thermal models indicate cooling from
ca. 165-150 Ma. In conjunction with ⁴⁰Ar/³⁹Ar K-feldspar data, the results indicate cooling was due to relatively slow
erosional denudation, and not thermal relaxation following Jurassic tholeiitic magmatism. Denudation was most likely
associated with the formation of the Jurassic rift system across Antarctica that marked the initial breakup of Gondwana.
This is the oldest episode of denudation associated with formation of the present day TAM