Continental ribbons within the southern North Atlantic rift system: attributes, origins, and consequences

Tectonic inheritance often plays a significant role in the evolution from continental rifts to passive rifted margins in extensional settings. Continental ribbons, which constitute intact continental fragments that remain tethered to their parent plates within rift systems, can form through interacting propagating rifts in pristine lithosphere but can also represent the lasting manifestation of pre-rift lithospheric heterogeneity. In the southern North Atlantic rift system, which transects the vestiges of the older Paleozoic Appalachian-Caledonian orogen, large continental ribbons are plentiful, arguably more so than anywhere else in the entire Atlantic Ocean. The spatial distribution of these ribbons, wrenched away from the North American, European, and Iberian plates during Mesozoic rifting and breakup of the Pangean supercontinent, provides insights into the pre-rift orogenic architecture of the lithosphere. This complex inheritance would go on to influence strain partitioning and sedimentary basin evolution during subsequent rifting and extensional reactivation. Studying these key components of rift systems and their consequences is often complicated by sparse seismic coverage due to their limited resource potential and their more distal locations. Yet, the characterization of continental ribbons at the lithospheric scale is necessary for their faithful incorporation into basin and plate reconstructions. To that end, alternate and complementary geophysical methodologies, such as potential field analysis, are needed to infill sparse seismic constraints and properly capture the physical characteristics of these impactful features. In this presentation, I will discuss the continental ribbons of the southern North Atlantic, the methods used to characterize their attributes, their likely tectonic origins, and how this information can be used to improve and quantify their contribution to reconstructions of the region.