Tectonic and Paleomagnetic Insights into Southern North Atlantic Rifting: An Integrated Onshore-Offshore Study of the Newfoundland Margin, Eastern Canada

Abstract

The tectonic and plate kinematic evolution of the Newfoundland margin, a key part of the eastern Canadian continental margin, was shaped by protracted rifting during the breakup of North America and Europe during the Mesozoic era. Through an integrated analysis of offshore seismic data, fault kinematics, and paleomagnetic records, the study investigates how inherited crustal structures, multi-phase extension, and plate-scale motion collectively influenced the development of this rifted margin. Three regions are central to this investigation: the Flemish Pass Basin, the southwestern Grand Banks, and the Notre Dame Bay Magmatic Province. In the Flemish Pass Basin, high-resolution 3D seismic reflection data reveal a complex fault network formed through multiple, non-coaxial rifting events. The vertical propagation and repeated reactivation of fault systems point to the influence of mechanical anisotropy and evolving stress orientations. These observations challenge simplified models of passive margin evolution and emphasize the role of structural inheritance. In the southwestern Grand Banks, 2D seismic data and slip tendency analysis demonstrate that inherited Mesozoic faults continue to accommodate strain under the present-day stress regime, underscoring the long-term persistence of crustal weaknesses. This has important implications for offshore seismic hazard. New paleomagnetic data from ~148 Ma Mesozoic intrusions in the Notre Dame Bay constrain plate motion during the final stages of rifting. The characteristic remanence directions confirm that the Newfoundland Block moved coherently with the North American plate, supporting models of tectonic stability and refining the Jurassic segment of the North American apparent polar wander path. Together, these results reconstruct a more dynamic picture of rifted margin evolution, demonstrating how fault reactivation, inherited structures, and stable plate motion collectively shaped the Newfoundland margin, with implications for plate tectonics, seismic hazard, and subsurface exploration.