It really helped us understand the processes involved with rifting
," says Cecile Doubre, a tectonophysicist at the Institut de Physique du Globe in Strasbourg.
Thus, the continent--ocean transition is more complex than previously thought, and depth-dependent stretching and/or simple shear have been invoked to explain how mantle could be exhumed during the rifting
process, and lead to asymmetrical conjugate margins.
These are the only directly observable rocks formed during the rifting
event that separated America and Africa.
Finding the rift extension led the team to propose that the mountains are actually the result of multiple orogenies, or mountain building episodes, involving a unique combination of continental collision, rifting
and uplift processes not previously seen together in other mountain ranges.
The reappearance of banded iron is more likely related to episodes of continental rifting
in the Neoproterozoic and deposition in enclosed or restricted rift basins close to hydrothermal vents along incipient mid-ocean ridges.
Many researchers view the rifting
as a passive process driven by tectonic stress from the distant collision between India and Asia.
This work is a breakthrough in our understanding of continental rifting
leading to the creation of new ocean basins," said Ken Macdonald, professor emeritus in the Department of Earth Science at the University of California, Santa Barbara, and who is not affiliated with the research.
The age and style of rifting
describe the nature of the continental breakup phase preceding orogeny.