Rifted margins classification and forcing parameters

Rifted margins are the result of the successful process of thinning and breakup of continents leading to the formation of new oceanic lithosphere. Observations on rifted margins are now integrating an increasing amount of multi-channel seismic data and drilling of several Continent-Ocean Transitions. Based on large scale geometries and domains observed on high-quality long-offset seismic lines, we illustrate a simple classification based on mechanical behavior and magmatic production. Therefore, rifted margins are not divided into opposing types, but described as a combination and continuum that can evolve through time and space from ductile to brittle mechanical behavior on one hand and from magma-poor to magma-rich on the other hand.

For instance, margins such as the Mauritania-Senegal Basin evolve north to south from a magma-poor to a magma-rich margin. Margins such as the Vøring one suffered different rifting episodes evolving from ductile deformation in the Devonian to more brittle and magma-poor rifting in the Cretaceous prior to a final magma-rich breakup in the Paleogene.

Thanks to these examples and to some others, we show the variability of the rifted margins worldwide but also along strike of a single segment and through time along a single margin in order to explore and illustrate some of the forcing parameters that can control the initial rifting conditions but also their evolution through time.