Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6432444 | Geomorphology | 2014 | 17 Pages |
â¢First multibeam bathymetry map of the Palomares Margin (western Mediterranean)â¢New clues in source to sink processes in a tectonically active marginâ¢First sedimentary processes assessment in the Gata and the AlÃas-Almanzora canyonsâ¢Differences in canyons' genetic-spatial development controlled by regional tectonicsâ¢First identification of sediment waves in the AlÃas-Almanzora Canyon mouth
The Palomares Margin, an NNE-SSW segment of the South Iberian Margin located between the Alboran and the Algerian-Balearic basins, is dissected by two major submarine canyon systems: the Gata (in the South) and the AlÃas-Almanzora (in the North). New swath bathymetry, side-scan sonar images, accompanied by 5Â kHz and TOPAS subbottom profiles, allow us to recognize these canyons as Mediterranean examples of medium-sized turbidite systems developed in a tectonically active margin.The Gata Turbidite System is confined between residual basement seamounts and exhibits incised braided channels that feed a discrete deep-sea fan, which points to a dominantly coarse-grained turbiditic system. The AlÃas-Almanzora Turbidite System, larger and less confined, is a good example of nested turbiditic system within the canyon. Concentric sediment waves characterize the AlÃas-Almanzora deep-sea fan, and the size and acoustic character of these bedforms suggest a fine-grained turbidite system. Both canyons are deeply entrenched on a narrow continental shelf and terminate at the base of the continental slope as channels that feed deep sea fans. While the AlÃas-Almanzora Turbidite System is the offshore continuation of seasonal rivers, the Gata Turbidite System is exclusively formed by headward erosion along the continental slope. In both cases, left-lateral transpressive deformation influences their location, longitudinal profiles, incision at the upper sections, and canyon bending associated with specific fault segments.