Continent-Ocean Transitions, how do they form? An example from Sergipe Alagoas, Brazil

Traditional views of the boundary between ocean and continent tend towards relatively simple models, partly due to the lack of geophysical data that image these areas. We present an example of an ocean-continent transition spanning an area of over 22000km2 from the Sergipe Alagoas Basin, a volcanic rifted margin offshore central Brazil. Using recently acquired, high resolution 2D seismic data it is possible to define the ‘building blocks’ of the ocean continent transition in this area, consisting primarily of seaward dipping reflectors and large areas of volcanic deposits. The geometries recorded in seaward dipping reflectors are interpreted to represent a steady increase in accommodation due to extension. The large volcanic areas are interpreted to represent areas of lesser extension and a relatively fixed magma source. These new observations based on geophysical data from these settings could have important implications for our view on the early processes of continental break up.