Prebreakup Sedimentary and Volcanic Sequences on Rifted Continental Margin of Wilkes Land, Antarctica: ABSTRACT

The transition zone from continental crust to oceanic crust on the Wilkes Land, Antarctica, margin was surveyed with 24-fold multichannel seismic reflection along 1800 line-km in 1984. The northward transition from extended continental crust to normal oceanic crust is characterized by a progression through three distinct volcanic sequences. The first, deposited on extremely thin continental crust, is interpreted to be a flood basalt, presumably deposited during the late rifting stage. The second, which overlaps the first at its northern end, is a seaward-dipping reflector sequence that forms anomalously thick oceanic crust. The third, which in turn onlaps the second, is normal oceanic crust with a rough upper surface and no internal reflectors.