The tectonic evolution of the Nova Scotian passive margin includes a Late Triassic-Early Jurassic rift phase and two major episodes of postrift subsidence spanning Jurassic to early Tertiary time. Rifting resulted in two classes of extensional basins characterized by opposite polarities of basinforming faults, and different levels of crustal detachment. Episodic passive-margin development is recorded by unconformity-bounded sequences that reflect differences in depositional systems and distribution of sedimentary facies. Seismic-stratigraphic sequences, separated by unconformities, match these cycles of rift and postrift subsidence, and reflect major reorganizations of oceanic plates.

Transfer fault zones accommodate four extensional tracts that are characterized by different extensional and postrift subsidence. The Sable extensional tract became the major postrift depocenter, as localized drainage patterns along its eastern edge fed clastics into Sable basin. Postrift structural modifications include seaward-dipping detachments within the sedimentary cover, as well as salt mobility. The combined effect of increased subsidence, structurally controlled dispersal systems, and postrift faulting resulted in the accumulation of hydrocarbons in Sable basin.