Print this page(Palae)Oceanographic, Structural and Biogenic Controls from Contourite Depositional Systems Along the Northern Pathway of the Mediterranean Outflow Water
David Van Rooij1, Francisco Javier Hernandez-Molina2, Jorgei Iglesias3, Gemma Ercilla3, Maria Gomez-Ballesteros4, Estefania Llave5, Ben De Mol6, Dominique Blamart7, Ian Nicholas McCave8, and Jean-Pierre Henriet1
1Renard Centre of Marine Geology, Ghent University, Gent, Belgium
2Universidad de Vigo, Vigo, Spain
3CMIMA-CSIC, Barcelona, Spain
4Instituto Espanol de Oceanografia, Madrid, Spain
5Instituto Geologico y Minero de Espana, Madrid, Spain
6Universitat de Barcelona, Barcelona, Spain
7LSCE-IPSL-UVSQ, Gif-sur-Yvette, France
8Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom
A large amount of contourite drifts has been described outside the deep thermo-haline circulation. These smaller-sized drifts are located along mid-slope continental margin sites and have, beside the obvious palaeoceanographic control, a distinct morphostructural or even biogenic control. The most impressive of these contourite depositional systems (CDS) is related to the Mediterranean Outflow Water (MOW) in the Gulf of Cadiz. Its evolution and morphology are controlled by the temporally variable outflow and branches of the MOW since the Upper Pliocene. Outside the Gulf of Cadiz, the MOW follows northward course in the Atlantic Ocean. Evidently, the kinetic flow of the MOW diminishes through mixing with other water masses. Nevertheless, here we present two CDS which are located and interconnected along this northerly MOW pathway. Their characteristics provide insight in the temporally variable steering, geometry and occurrence of CDS along margins. The first CDS is located in an intraslope basin, located between the Cantabrian margin and the Le Danois Bank. The dominant steering of this CDS happens through interaction of the MOW with the Le Danois Bank and the morphotectonic setting of the intraslope basin. Its depositional architecture and evolution is largely similar with the Cadiz CDS, in spite the morpho-tectonic features which have shaped and conditioned the distribution and formation of different types of contourites. The second CDS has a longer geological history, but has also been affected by the northernmost MOW occurrence. Along the eastern slope of the Porcupine Seabight (Ireland), the introduction of the MOW was responsible for a drastic change in palaeoenvironment, enabling the growth of deep-water coral banks. The presence of these biogenic structures together with a pronounced glacial influence has shaped several contourite drift types.
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