Tectonostratigraphic Evolution of the Barbados Accretionary Prism and Surrounding Sedimentary Basins within the Southeastern Caribbean- South America Plate Boundary Zone



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This dissertation presents an integrated, mega-regional, subsurface study of the southeastern Caribbean plate margin that incorporates observations from gravity, seismic refraction, outcrop, and ~20,000 line km of high-resolution, 2D seismic reflection data tied to wells. The objective of the study is to better understand the tectonic and basinal transitions from the Lesser Antilles subduction zone (LASZ) - characterized by the subduction of the South American oceanic crust beneath the overriding Caribbean plate and the ~300-km-wide, deepwater Barbados Accretionary Prism (BAP) - to the arcuate, obliquely-convergent and transpressional southeastern Caribbean- South American plate boundary zone - characterized by a complex suite of uplifted transpression provinces, foreland basins, and hybrid sedimentary basins. Early Cretaceous allochthonous, arc terranes, including the island of Tobago and its offshore component, the Tobago-Barbados Ridge (TBR) were accreted along the deeply-buried, lithospheric trace of the LASZ, and tectonically transported along northern South America to their present-day position at the leading eastern edge of the Caribbean plate where the terranes form a backstop for the Barbados accretionary prism. Along-strike changes in structures of the BAP are related to progressive phases of deformation that involve thickening of prism strata against the TBR backstop, frontal accretion, horizontal shortening, mud diapirism, rotation and uplift of structures, and backthrusting. The Galera Tear Fault Zone (GTFZ) that formed along the Mesozoic continent-ocean boundary of the northeastern South American plate accommodates the differential deformation between provinces of the Barbados Accretionary Prism within the LASZ to the northeast and provinces of the oblique collision and strike-slip zone near Trinidad. Basins affected by subduction-to-strike-slip plate boundary interaction undergo superimposed areas of compressional-transpressional, extensional-transtensional, and strike-slip deformation. The elongate, V-shaped, and southward-tapering Barbados piggy-back basin acts as a depressed sink for sediments derived from source areas on the uplifted, continental provinces affected by the oblique collision and strike-slip zone. Deformation along the margins of the Barbados basin influence the observed geometry, shape, and dimensions of mass transport complexes (MTCs), which are up to 500 m thick and are funneled down the synclinal basin axis.



Basins, Tectonics


Portions of this document appear in: Gomez, Shenelle, Dale Bird, and Paul Mann. "Deep crustal structure and tectonic origin of the Tobago-Barbados ridge." Interpretation 6, no. 2 (2018): T471-T484. doi: 10.1190/INT-2016-0176.1. Note that modifications have been made to this chapter so its content is not identical to the published version.