Looking for clues to paleoceanographic imprints: A diagnosis of the Gulf of Cadiz contourite depositional systems

Abstract

A new morphosedimentary map of the Gulf of Cadiz is presented, showing the contourite depositional system on the gulf's middle slope. This map is constructed from a broad database provided by the Spanish Research Council and the U.S. Naval Research Laboratory. Our map shows that this contourite depositional system comprises five morphosedimentary sectors: (1) proximal scour and sand ribbons; (2) overflow sedimentary lobe; (3) channels and ridges; (4) contourite deposition; and (5) submarine canyons. The Gulf of Cadiz contourite depositional system stems directly from the interaction between Mediterranean Outflow Water and the seafloor; its morphosedimentary sectors are clearly related to the systematic deceleration of the Mediterranean Outflow Waters westward branches, bathymetric stress on the margin, and the Coriolis force. The slope's depositional system can be considered as a mixed contourite and turbidite system, i.e., a detached combined drift and fan.

Ferromanganese nodules and micro-hardgrounds associated with the Cadiz Contourite Channel (NE Atlantic): Palaeoenvironmental records of fluid venting and bottom currents

“…Kenyon and Belderson, 1973;García et al, 2009). The GDR forms a topographic high that constricts the MOW circulation pathways, dividing the current into minor branches (Nelson et al, 1993;Hernández-Molina et al, 2003). The lower core ofthe MOW has acted with different intensity in the CCC during the Late Quaternary.…”

“…It also has several depositional and erosive features such as contourite channels, furrows and marginal valleys (e.g. Hernández-Molina et al, 2003Llave et al, 2006;García et al, 2009). Part of the CDS has developed on the offshore extension of the Betic Chain.…”

“…1), named the channel and ridge sector because of its morphosedimentary characteristics (Llave et al, 2001;Hernández-Molina et al, 2003). In this sector, tectonics-and especially diapirismplaya major role in controlling the architecture of the CDS.…”

“…The MOW is a strong current that circulates across the slope of the Gulf of Cadiz from the SE to the NW (e.g. Madelain, 1970;Melieres, 1974;Loubere, 1987;Ochoa and Bray, 1991;Hernández-Molina et al, 2003;. The MOW divides into two main cores: Mediterranean upper and lower waters, moving across the upper slope (500-800 m) and the middle slope (800-1200 m), respectively (e.g.…”

“…Kenyon and Belderson, 1973;Faugeres et al, 1984;Llave et al, 2001;Hernández-Molina et al, 2003;. This CDS is composed of five morphosedimentary sectors: the proximal scour and sand ribbon sector; the overflow sedimentary lobe sector; the channel and ridge sector; and the contourite drift and submarine canyon sector Hernández-Molina et al (2003).…”