In a study to be published in the AGU journal "Tectonics", seismic data and analog modeling results revealed that a system of elongated extensional trenches (of the "basin-&-range" type) developed in the thickest zone of the Barbados accretionary prism. Synchronous with this extension, compression occurred at the front of the accretionary prism (frontal accretion zone), and compression was also active at the inner edge of the prism (characterized by back-thrusting). The interpretation proposed in this study involves a spreading of the superficial part of the accretionary prism due to a viscous response associated with tectonic thickening of the deepest parts of the prism. This interpretation is consistent with the fact that extension is limited to the axial part of the prism and coincides with the zone where the prism is thickest. The deep zone of viscous behavior is interpreted as shale-rich sedimentary domains intensely deformed by penetrative deformation. Analog sand-silicone models controlled by X-ray scanner were used to simulate the deformation distribution compared to the Barbados accretionary prism, as observed on available seismic reflection data. A bilayer model with an upper brittle zone and a lower ductile part is best suited to account for the observed deformation. We present here the data on which this study is based: (1) seismic data acquired as part of an industrial consortium under the auspices of the “Comité d'Etudes Pétrolières et Marines” (CEPM), and (2) raw data from analog modeling experiments made at IFPEN. The seismic data comprise time-migrated data from CEPM's CRV128 and AN107 profiles, and a depth conversion of the AN107 profile. Raw 2D tomography data from analog experiments 1385_214, 1385_114 and 01258. 3D serial sections of experiment 01258 are also shown.