Submarine Cascais Canyon as a sediment conduit to the deep sea : comparison with adjacent slopes

Submarine canyons are known to be important conduits that trap, accumulate and deliver both natural and anthropogenic sediments from the shelf to the deep sea. Ten multi-cores from the Cascais Canyon and from the neighbour slopes (off Estremadura and Sines) were dated by 21Opb methodologies and analyzed for texture, major and trace metals to evaluate the role of submarine canyons in the transport of anthropogenic metals to the abyssal plains. Higher accumulation mass rates were determined in the upper Cascais Canyon than in the lower canyon and slopes. Enrichment factors (EF) were used to evaluate the level of metal enrichment in the studied areas. EF values exceeding natural background concentrations were obtained for Pb suggesting an anthropogenic and/or diagenetic source for Pb enrichment in the Cascais Canyon, but also, to a lesser extent, in the Estremadura and Sines slopes. Studies of provenance based on the ratio of different stable Pb isotopes can help to determinethe origin of such metal in the sediments.

Keywords

Contaminação de águas Sedimentos marinhos Elementos maiores Metais pesados Canhão Submarino de Cascais (Portugal) Margem Continental Portuguesa

URI

http://hdl.handle.net/10400.9/826

Citation

Costa, A. M.; Mil-Homens, Mário; Lebreiro, Susana; De Stigter, H.; Richter, T.; Boer, Wim; Trancoso, M. Ascenção; Melo, Zenaida; Mouro, F.; Mateus, M. - Submarine Cascais Canyon as a sediment conduit to the deep sea : comparison with adjacent slopes. In: 6º Simposio sobre el Margen Ibérico Atlántico : MIA 09, Oviedo, 1-5 de diciembre de 2009

Collections

GMC - Comunicações em actas de encontros científicos internacionais

Full item page