Contrasting structures and hydrocarbon accumulation of passive continental-margin basins along both sides of the Atlantic

This study investigates the structural and petroleum system heterogeneity across the conjugate passive margins of the Atlantic Ocean. Through an integrated analysis of seismic, geological, and geochemical data, the margins are subdivided into five major tectonic segments comprising six distinct basin types. Each basin type exhibits a three-stage tectono-stratigraphic evolution: intracratonic rifting, transitional intercontinental rifting, and passive-margin drifting. Detailed analysis of giant fields reveals type-specific accumulation models. In the Southern South Atlantic, syn-rift and passive-margin source rocks charge rift and fan reservoirs. The Central South Atlantic is characterized by extensive evaporite deposits, which facilitate major sub-salt carbonate and post-salt turbidite plays. The Northern South Atlantic is marked by thick passive-margin sedimentary wedges that host slope-confined giant turbidite reservoirs. The Central Atlantic is dominated by shelf-edge delta and deepwater fan plays, whereas the North Atlantic primarily relies on structural traps sourced from rift-related systems. Deltaic basins (e.g., the Niger Basin) develop self-sourced hydrocarbon accumulations organized within four concentric structural zones. This segmentation framework clarifies controls on giant field distribution and guides future exploration.