First evidence of a main channel generated by the Mediterranean Outflow Water after its exit from the Gibraltar Strait

An extensive terrace comprising sandy sheeted drifts characterises the proximal sector (close to the Straits of Gibraltar) of the Contourite Depositional System (CDS) of the Gulf of Cadiz and the western continental margin of Portugal. A novel morphosedimentary study over this terrace has been executed based on new multibeam echosounder data, seismic profiles, and surficial sediments samples collected during the CONTOURIBER-1 Cruise (2010). Based on that study, an impressive large channel laterally connected with the central part of the Strait of Gibraltar (Camarinal Sill) has been identified. It is associated southwestward with a huge contourite levee (sand bank), which has been generated by overflow processes related to the Mediterranean Outflow Water (MOW). In the middle to the distal part of the terrace, there are other minor channels, erosional scour alignments and depositional features. The mapping of all these features coupled with CTD data allows to further understand the pathway and deceleration of the MOW, in addition to aid the conceptual identification of contourite terrace.El sector proximal del Sistema Deposicional Contornítico (SDC) del Golfo de Cádiz y oeste de Portugal se caracteriza por una extensa terraza contornítica en la que se desarrollan drifts laminares arenosos. Sobre esta terraza se ha realizado un novedoso estudio morfosedimentario en base a datos batimétricos de ecosonda multihaz, registros sísmicos y muestras superficiales, adquiridos en la campaña oceanográfica CONTOURIBER-1 (2010). Se ha identificado un extenso canal sobre dicha terraza conectado lateralmente con la parte central del Estrecho de Gibraltar (Umbral de Camarinal) y bordeado por el SO por un dique (levee) contornítico (banco arenoso). La génesis del canal se relaciona con el desbordamiento sucesivo de la Masa de Agua Mediterránea de Salida (MOW) en el Golfo de Cádiz. En la parte media y distal de la terraza contornítica existen canales menores, surcos erosivos y rasgos deposicionales, cuya cartografía, junto al análisis de datos de CTD, permite entender mejor la circulación y deceleración de la MOW, así como la caracterización conceptual de las terrazas contorníticas.Publicado