Morphometric analysis and genetic implications of pro-deltaic sea-floor undulations in the northern Alboran Sea margin, western Mediterranean Basin

Abstract

Several fields of seafloor undulations from pro-deltaic wedges in the northern margin of Alboran Sea, Western Mediterranean Basin, are described in this paper. A series of elongated, subparallel bathymetric undulations are distinguished in the foreset-to-bottomsets regions of the Holocene pro-deltaic wedges related with the Guadalfeo and Verde–Seco rivers. Multibeam data, surficial sediment samples and high-resolution seismic profiles have been used in this study, and integrated in a Geographical Information System. Quantitative measurement of key morphometric parameters (wave-length, height, asymmetry, length and wave-form index) was performed on multibeam data and seismic profiles using the ArcGis software. Wave-form index and depth data were analysed statistically, and a cluster analysis was carried out in each area. According to these results, we infer that sea-floor undulations in the study areas are best explained by the influence of strong sediment flows normal to bathymetric contours, probably coupled with the effect of subsequent slow sediment deformation processes such as sediment creeps. The influence of bottom-current activity is considered less likely, as the position of river mouths and the very high slope gradients seems to be the key factors which control the development of these sea-floor undulations. The Alboran Sea sea-floor undulations are compared with those of other fields in shallow-water environments and the different processes of formation evaluated.