Multi-phase intra-plate rifting and deformable plate modelling of the Northeast Atlantic back to the Permian

Abstract

The Northeast Atlantic was one of the last regions of the Pangea supercontinent to undergo complete break-up, experiencing over 200 million years of episodic continental stretching before final separation. This prolonged tectonic evolution has been studied using recent geological and geophysical data obtained from the mid-Norwegian and East Greenland margins, which provide constraints on the timing, location, amount, and direction of extension. To analyse these parameters, we adopt a basin-to-plate scale approach and develop a deformable plate reconstruction. We implement four discrete phases of rifting: Phase I (264–247 Ma), Phase II (166–140 Ma), Phase III (125–110 Ma), Phase IV (80–56 Ma), with a progressive shift in extension direction from east-west to southeast-northwest. A key component of our methodology is the restoration of basin hinges for each rift episode. These hinges mark the outermost rigid boundaries of the deforming region and provide essential structural constraints. Over time, the width of the rifting domain narrows from approximately 300 km to 220 km, depending on margin location. Our model predicts cumulative stretching ranging from 240 km in the north to 310 km in the south of the domain. Extension rates and amounts vary by phase; for a mid-margin location, Phase I accounts for approximately 90 km of extension at 0.5 cm/yr, Phase II for 30 km at 0.13 cm/yr, Phase III for 90 km at 0.58 cm/yr, and Phase IV for 80 km at 0.32 cm/yr. By comparing forwards- and backwards-in-time crustal thickness reconstructions, our results suggest an initial crustal thickness exceeding 35 km before the onset of Permian rifting, and that lateral variations of non-linear stretching were likely. Our framework indicates that both rigid and deforming reconstructions should be developed in tandem with regional basin-scale constraints. Our model will form the basis for additional regional temporal and structural investigations including the Barents Sea, North Sea, and Northwest North Atlantic.