Three Dimensional Seismic Reflection Investigation of Fluid Flow and Structural Evolution in the Frontal Part of the Accretionary Prism of the Northern Barbados Trench

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The mechanics of accretionary wedge growth along deep sea trenches is a fundamental problem in plate tectonics. Although models exist which predict seafloor shape, sparse information exists on the geometry of deformation structures, strength of the accreting sediments, or shear resistance along the base of the fault zone which controls underthrusting. It is well recognized that fluids play a crucial role in sediment accretion, deformation, diagenesis, and metamorphism in accretionary zones, but study of fluid pathways and timing of dewatering have just begun. The importance of fluids in controlling the strength of rocks and shear resistance is recognized, but little data exists to investigate these properties spatially or temporally. The present project will conduct a high-resolution three- dimensional seismic reflection survey of the accretionary prism offshore Barbados in the zone of initial off-scraping, underplating and deformation of sediments. The objectives are to characterize the structural geometries, and identify fluid pathways in the frontal part of the accretionary prism. The seismic data will be constrained by an extensive suite of other geophysical data, as well as the results of previous ocean drilling in the region. Results from this project will be used in planning additional drilling in Barbados.