What can potential field data really tell us about Continent-Ocean transitions?

define the distribution of crustal types at continental margins, with specific focus on the conjugate Australia- Antarctica margins. Previous studies have used features in gravity maps as a proxy for the pre-rift location of plate boundaries. Instead, we discuss the use of potential field data to define the boundaries of stretched continental crust on a regional scale, and demonstrate this process for the conjugate margins of South Australia and Antarctica. In a companion paper (Whittaker et al, 2010) we show how these boundaries are used along with estimates of crustal thickness to determine the location of the plate boundaries prior to rifting, and ultimately to derive full-fit plate tectonic reconstructions.