Grenville-age basement provinces in East Antarctica; evidence for three separate collisional orogens

Three Grenville-age provinces can be distinguished in East Antarctica with U-Pb zircon data. The Maud, Rayner, and Wilkes provinces each have a distinctive age signature for late Mesoproterozoic-early Neoproterozoic magmatism and high-grade metamorphism and are correlated with similar rocks in the Namaqua-Natal (Africa), Eastern Ghats (India), and Albany-Fraser (Australia) provinces, respectively. These crustal segments represent three separate collisional orogens. They are separated by regions of intense late Neoproterozoic-Early Cambrian tectonism, consistent with their juxtaposition during the final assembly of Gondwana and indicating that previous models for a single, continuous, Grenville-age mobile belt around the East Antarctic coastline should be discarded.