Structure and Geodynamics of the Gulf of Cadiz
M.A. Gutscher
A recent marine seismic survey imaged an active accretionary wedge west of the Gibralter region. The Gibralter region has several different features that if taken together with new seismic, tomographic, and GPS data indicate that there is active subduction east of the Gulf of Cadiz. These features include the arcuate Betic-Rif mountain, belt, the western Alboran Sea and a chaotic sedimentary melange in the Gulf of Cadize.

 Figure 1: Map of the Gulf of Cadize.

Evidence for this subduction is provided by a new tomographic cross-section model that Images an east dipping, high p-wave velocity body that extends from the surface in the Atlantic domain west of the Gibralter arc, east to 660 km depth beneath the western Alboran sea.

Figure 2: Tomographic model of Gulf of Cadize and Gibralter Region

Multichannel seismic data images an eastward thickening wedge of deformed sediment (the aforementioned melange) that overlays gently dipping undeformed sediment. The step like deformation of these sediments is interpreted to be thrusts that bound imbricate slices within an active accretionary wedge.

Figure 3: Multichannel seismic image of Cadize Accretionary wedge.