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Seismic Stratigraphy and Structure of the Crest of the Barbados Prism and Adjacent Tobago Basin

Nysha Chaderton, Lesli Wood, and Paul Mann
The University of Texas at Austin, Austin, TX

The Barbados Accretionary Prism (BAP), located along the east margin of the Caribbean Plate, represents the only prism in the world with active oil and gas production along with natural seeps on Barbados Island and on the surrounding seafloor. Recent oil geochemistry of samples from Barbados and offshore areas indicates the presence of a widespread source-rock facies. To further investigate this unique petroleum system, we present 2D seismic data illustrating the structural and stratigraphic framework, the crest of the prism along the Barbados ridge and the adjacent Tobago Forearc Basin (TFB). The boundary between the Barbados ridge and the Tobago basin is a fold and thrust belt active from the Eocene to the present. Wedging of sequences in the Tobago basin show that thrusting produced accommodation space filled by deepwater clastic sediments mainly derived from the south. Large low-angle thrusts form major anticlinal highs. The Barbados ridge itself is a large arch developed on the hanging wall of this thrust system. Flexure of the ridge produces a system of ridge-parallel normal faults. The Oceanic Formation on Barbados can be traced into the adjacent deep water areas. The paleobathymetry of the Oceanic Formation on Barbados shows that the arching and uplift of the Barbados ridge occurred in Mid-Miocene time. The Oceanic Formation on Barbados forms a sealing for hydrocarbons trapped in Eocene deep marine clastic reservoirs of the deformed prism. Analogous areas offshore are illustrated using seismic profiles.