An embayment in the East Antarctic basement constrains the shape of the Rodinian continental margin

Abstract East Antarctic provinces lay at the heart of both Rodinian and Gondwanan supercontinents, yet poor exposure limited geophysical data provide few constraints on region’s tectonic evolution. The shape Mawson Continent, stable nucleus Antarctica, is one Antarctica’s most important, but contested features, with implications for global plate reconstructions local models. Here we show a major marginal embayment 500–700 km wide, cuts into basement in South Pole region. This embayment, defined by new aeromagnetic other data, truncates which distinct from flanking Weddell Sea. We favour late Neoproterozoic rifting model formation discuss analogies continental margins. associated help define supercontinental reconstructions, while inherited geometry likely influenced evolution paleo-Pacific margin Gondwana.