Rift to drift evolution and crustal structure of the Central Atlantic: the Sidi Ifni-Nova Scotia conjugate margins

The breakup of Pangaea in Early Mesozoic times initiated first in the Central Atlantic region, where Triassic to Early Jurassic lithosphere extension led to continental breakup and oceanic accretion. The Central Atlantic rifted margins of NW Africa and eastern North America exhibit complex along-strike variations in structural configuration, crustal geometries, and magmatic budget at breakup. Quantifying these lateral changes is essential to understand the tectonic and geodynamic processes that dominated rifting and continental breakup. The existing seismic refraction lines along the African side and its American conjugate provide good constraints on the 2D crustal architecture of several Central Atlantic margins. However, they are insufficient to quantify the ambiguous lateral variations.

This work examines the central segment of the Moroccan Atlantic margin, which is named here the Sidi Ifni-Tan Tan margin. Using 2D seismic reflection and well data, we quantify the stratigraphic and structural architecture of the margin. We then use this to constrain 2D and 3D gravity models, to predict crustal thickness and types. Ultimately, our results are integrated with previous findings from the conjugate Nova Scotia margin, on the Canadian side, to propose a rift to drift model for this segment of the Central Atlantic and discuss the tectonic processes that dominated rifting and decided the fate of continental breakup.