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The East Orphan, Porcupine, and Galicia Interior basins are several of the most promising basins for hydrocarbon exploration along the rifted continental margins of the southern North Atlantic Ocean. Despite having formed at similar geological times, the basins exhibit fundamental differences in symmetry, crustal thickness, sedimentary cover thickness, and amount of extension. Interpretation of seismic reflection and well data was integrated with published 3D grids of depth-to-basement and Moho proxy depth to interpret and restore select seismic reflection lines. Publicly available kinematic evolution models were also integrated to evaluate and compare the restored seismic reflection lines in a more global regional context. Interpretation of five seismo-stratigraphic units and three tectonostratigraphic megasequences along the East Orphan, Porcupine, and Galicia Interior basins reveals similar seismic character for each unit and comparable tectonic history. The structural restoration of the selected lines indicates that evolution, sedimentary cover thickness, faulting style, crustal structure, and kinematic evolution of the East Orphan and Porcupine basins differ significantly. A variable and asymmetrical crustal structure is found in the East Orphan Basin contrasting with the elongated and symmetric Porcupine and Galicia Interior basins. Rift domain maps of the three basins reveal that they are each underlain by hyperextended crust, with possible exhumed mantle in the centre of the Porcupine Basin. Based on a holistic analysis of the results obtained, the linkage between the East Orphan and the Porcupine basins seems implausible, but rather a contemporaneous relationship is interpreted. Moreover, a potential connection between the Galicia Interior Basin and the Porcupine Basin during the Early to Late Jurassic is proposed. Such scenarios imply an oblique and synchronous rifting evolution around the Bay of Biscay triple junction of the southern North Atlantic. • The connection between the East Orphan and the Porcupine basins is unlikely. • An ancient connection between the East Orphan and the Rockall basins is proposed. • A continuous basin formed by the Porcupine and Galicia Interior basins during the Early to Late Jurassic is proposed. [ABSTRACT FROM AUTHOR]

Reconstructions of the opening of the North Atlantic Ocean generally result in the Orphan Basin, offshore Newfoundland, Canada, lying approximately conjugate to the rift basins on the Irish Atlantic margin at the onset of seafloor spreading toward the end of the Early Cretaceous. Most of these plate reconstructions have involved rigid plates with plate motions based solely on the interpretation of oceanic magnetic anomalies. In particular, these reconstructions often show the Rockall Basin, west of Ireland, forming a continuous Mesozoic basin with the West Orphan Basin, offshore Newfoundland. However, more recent plate reconstructions involving deformable plates have called this conjugate relationship into question. The goal of this study is to investigate the validity of this potentially continuous basin system by reconstructing and restoring present-day seismically-constrained geological models both spatially and temporally back to their original configurations pre-rift. By comparing the reconstructions in terms of sedimentary package thicknesses and crustal thicknesses in 3D, using both rigid and deformable plate reconstructions to orient the reconstructed models, we are able to test different basin connectivity scenarios using a multidisciplinary approach. Our analysis provides subsurface geophysical support for the hypothesis that the Rockall Basin was originally conjugate to and continuous with the East Orphan Basin during Jurassic rifting, later linking to the West Orphan Basin as rifting evolved during the Early Cretaceous. This complex basin evolution example highlights the need for using 3D rifting mechanism models to properly understand the fundamental driving forces during rifting and has significant implications for assessing basin prospectivity across conjugate margin pairs. [ABSTRACT FROM AUTHOR]