A Deep-sea Channel in the Northwestern Mediterranean Sea: Morphology and seismic structure of the Valencia Channel and its surroundings |
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Authors: | Belen Alonso Miquel Canals Alberto Palanques Jean-Pierre Rehault |
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Institution: | (1) Dept. de Geologia Marina i Oceanografia Física, Institut de Ciències del Mar, CSIC, Passeig Joan de Borbó s/n, 08039 Barcelona, Spain;(2) Grup de Recerca en Geociències Marines, Dept. de Geologia Dinàmica, Geofísica i Paleontologia, Universitat de Barcelona, 08071 Barcelona, Spain;(3) Département des Sciences de la Terre, Université de Bretagne Occidentale, Avenue Le Gorgeu, 29287 Brest, France |
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Abstract: | The 400 km long Valencia Channel occupies the axis of the Valencia Trough in the Northwestern Mediterranean. Four different types of seismic reflection profiles were used to analyze the morphology and structure of the Valencia Channel with regard to the role played by both margins, Balearic and Iberian, of the Valencia Trough. From a detailed morphoseismic analysis of the Valencia Channel, its upper, middle, and lower courses can be characterized as follows: (1) in the upper course, tributaries are short and only slightly incised, with recent mass-transport deposits occurring on the adjacent continental slopes; (2) in the middle course, the channel deepens, and tributary valleys merge into it; and (3) the lower course begins after a sudden change in the direction of the channel, has a meandering path, is flanked by levees, and is fed by some valleys.During the Pliocene and Quaternary, at least four erosional and filling phases are observed in seismic profiles of the lower course of the Valencia Channel. The varying intensity of mass-transport processes and associated retrogressive slumping, which are related with fluctuations in sediment supply and relative sea-level changes, have played a major role in the formation, maintenance and deepening of the Valencia Channel. In addition to these sedimentary processes, a basement tectonic control and some morphostructural features affect the direction of the Valencia Channel locally. |
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Keywords: | Deep-sea channel Mediterranean morphostructure Valencia Trough |
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