Resumen de Arquitectura estratigráfica de los depósitos contorníticos del Pleistoceno Superior del Golfo de Cádiz: implicaciones paleoceanográficas de los eventos de Heinrich
Estefanía Llave Barranco, J. Schönfeld, Francisco Javier Hernández Molina, Thierry Mulder, Luis Somoza, Víctor Díaz del Río Español
A detailed stratigraphic analysis of Late Pleistocene-Holocene sedimentary series in the northernand central part of middle slope's contourite system in the Culf of Cadiz is presented. This work is based on a network of high- and very high-resolution seismic reflection profiles (Sparker, 3.5 kHzand Topas), and several up to 20 m long Calypso piston cores recovered during the IMAGES Vcruise on the RV Marion Dufresne 2. Both data allowed determining a stratigraphic stacking pattern of four depositional sequences (a-d) that are internally structured into W subunits. Subunits areformed of transparent seismic facies at the base that evolve into smooth, parallel reflectors of moderate to high amplitude facies in the upper part. This cyclicity in the acoustic architecture is likely related to lithological changes including coarsening-upward sequences. A chronostratigraphic framework using data from piston cores revealed that the subunits periodicity is related to Heinrichevents (H6 to HI). These data indicate that the Heinrich events have not only shut down the North Atlantic thermohaline circulation, but also influenced the spatial and vertical fluctuations of the Mediterranean Outflow Water in the whole Gulf of Cadiz.
