To facilitate an evaluation of hydrocarbon systems elements in offshore eastern Trinidad, we generated regional cross sections and a 1000-km-long conceptual, lithospheric-scale cross section from the Aves ridge to the Demerara plateau. The sections are based on interpretation of 2-D and 3-D seismic data, gravity and magnetics surveys, and published literature. Our results indicate that convergent-margin tectonism and rapid sedimentation first impacted the deep-water area of offshore eastern Trinidad in the latest Miocene. As much as 12 km of post-middle Miocene sediments are present south and east of the Caribbean–South American Plate boundary zone in the Columbus basin foredeep. The basin formed in response to subduction, tectonic loading, and progradation of the Orinoco delta. Well-imaged, northeast-trending buckle folds occur above the detachment fault(s) and are an important trap-forming element in the deep-water area. Deep-penetrating, active growth faults are the principal hydrocarbon migration pathways on the continental shelf but are absent in the deep-water exploration area. Seismic quality diminishes rapidly to the north of 11N latitude, in an area where highly irregular sea-floor topography marks active deformation and dewatering in the internal part of the Barbados accretionary complex.

We propose that the change in crustal type across the Mesozoic passive margin of northern South America controls the style and magnitude of strain above the main dcollement associated with the Cenozoic convergent margin. Contractional structures developed in Trinidad when continental lithosphere of the South American plate impinged on the subduction zone at the leading edge of the Caribbean plate. The positive buoyancy of continental lithosphere resists subduction, resulting in more earthquakes, a fold and thrust belt from eastern Venezuela to offshore eastern Trinidad with as much as 100-km shortening, and the southern limit of the Lesser Antilles volcanic arc. The transition to oceanic crust in offshore eastern Trinidad marks a change in tectonic environment from continental fold and thrust belt to accretionary prism above subducting oceanic crust.