Recent geophysical surveys were designed to investigate the breakup process between India and East Antarctica and the effect of igneous activity on the formation of the Antarctic passive margin and the crust between the Kerguelen Plateau and Antarctica in the Princess Elizabeth Trough (PET). The Kerguelen Plateau marks one of the two most voluminous Large Igneous Provinces (LIP) in an oceanic setting and is attributed to a mantle hotspot emplaced at 120 Ma ago, about 15 m.y. after the previously suggested onset of seafloor spreading between India and Antarctica. Geophysical data analyses and modeling reveal a wide zone of highly extended continental crust on the Antarctic margin of Mac.Robertson Land. The partial continental affinity of the Southern Kerguelen Plateau, as indicated by earlier seismic data and ODP drill samples further north, continues to the southernmost limit of the plateau. Here, the continental crust must have been enormously thinned and fragmented as part of the rifting process between India and Antarctica. Ocean-bottom seismograph data indicate a narrow corridor of oceanic-type crust beneath the PET. Magmatic accretion to the crust is widely observed on both the plateau and the PET region.