Ondas de sedimento de origen turbidítico en los márgenes y cuencas profundas del Atlántico

Abstract

Sediment wave fields located on the slope of the Selvage Islands (eastern Atlantic), south margin of the Orinoco Valley (Lesser Anti Has Sea), and distal continental margin of Colombia (Caribbean Sea) have been studied based on multibeam bathymetry Topas seismic profiles and sediment cores. These sediment waves occur on deep-sea areas (> 3.300 m water depth), and they are mostly characterised by large waves with crests oriented roughly parallel to the regional slope, assymetric cross-sections that indicate upslope migration, and a progressive downslope decrease in their dimensions. Seismically, they are defined by wavy bedding facies with a thicker sedimentary sequence on the upslope flank than that on the downslope flank. An unchannelised turbidity current origin has been proposed for these sediment wave fields. The sediment waves on the Agadir Basin are manteined by turbidity currents largely sourced from the Selvage volcanic islands; turbidity currents responsible for the Orinoco sediment wave field are interpreted being sourced from the Venzuela, Guyana and Surinam continental margins; and the sediment waves on the Colombia continental margin have been formed beneath turbidity currents which may result from the downslope evolution of slumps and mass-flows