Rheological inheritance controls the formation of segmented rifted margins in cratonic lithosphere

Observations from rifted margins reveal that significant structural and crustal heterogeneity develops through the process of continental extension and breakup. While a clear link exists between distinct margin structural domains and specific phases of rifting, the origin of strong segmentation along the length of margins remains relatively enigmatic and may reflect multiple competing factors. Given that rifting frequently initiates on complex tectonics sutures, structural inheritance is frequently invoked as an origin of margin segmentation, although to date no studies have clearly elucidated the link between inheritance and 3D rifted margin geometries. Here, we use recent observations from the Labrador Sea and thermal-mechanical simulations of continental rifting to constrain the effects of inherited variable lithospheric properties on margin segmentation. The modelling results demonstrate that N-S variations in lithospheric thickness, crustal structure, and rheology within the pre-rift Canadian Shield produce sharp gradients in rifted margin width and the timing of breakup, leading to strong margin segmentation across a range of geophysically-constrained rift parameters.