Jurassic silicic volcanism in the Transantarctic Mountains: Was it related to plate margin processes or to Ferrar magmatism?

Silicic volcanism in the Transantarctic Mountains, represented by rhyolitic tuff that mainly precedes
emplacement of the Ferrar Large Igneous Province, is important in interpretation of the tectonic evolution of the
Antarctic sector of Gondwana. Sr and Nd isotope data indicate that the tuffs are not directly related to Ferrar
magmatism nor to melting of the underlying Ross orogen crust yet zircon gives a U-Pb age of 182.7±1.8 Ma, similar to
the U/Pb age for the Ferrar. Distribution of the silicic tuffs along 1400 km of the Transantarctic Mountains suggests,
alternatively, a relationship to the Gondwana plate margin. Although West Antarctica comprises Mesoproterozoic
crustal terrains, few analyzed rocks are compatible isotopically with the Lower Jurassic tuffs. The source of the tuffs
must lie in unexposed Early Jurassic magmatic centers in West Antarctica or an unexposed crustal terrain beneath the
Transantarctic Mountains.