Resúmenes sobre el VIII Simposio MIA15, Málaga del 21 al 23 de Septiembre de 2015 Acoustic evidences of along-slope processes associated with mass movement deposits on the Madeira Island lower slope (Eastern Central Atlantic) Evidencias acústicas de procesos paralelos al talud asociados con depósitos de movimiento en masa en el talud inferior de la Isla de Madeira (Atlántico Central Oriental) C. Roque (1,2), P. Madureira (1), F.J. Hernández-Molina (3), A. Santos de Campos (1), R. Quartau (2,4), G. Carrara (5), F. Brandão (1), J.T. Vázquez (6) & L. Somoza (7) (1) EMEPC-Estrutura de Missão para a Extensão da Plataforma Continental, Paço de Arcos, Portugal cristina.roque@emepc.mamaot.pt cristina.roque@ipma.pt (2) IDL- Instituto Dom Luiz, Campo Grande, Lisboa, Portugal (3) Royal Holloway, University of London, UK (4) IPMA- Instituto Português do Mar e da Atmosfera, Lisboa, Portugal (5) GEOPHI Srl, Bologna, Italy (6) IEO- Instituto Español de Oceanografía, Málaga, Spain (7) IGME- Instituto Geológico y Minero de España, Madrid, Spain Abstract: The Madeira Island lower slope has been build-up mostly by along slope-processes associated with mass movement deposits as seen in GEBCO bathymetry, multibeam bathymetry, Parasound echosounder profiles and multichannel seismic reflection profiles. A plastered contourite drift (Madeira Drift) developed on this lower slope, being composed of seismic units D1, D2 and D3. The most probable water mass responsible for its deposition is the Antarctica Bottom Water (AABW). The youngest sediments of seismic units D2 and D3 are affected by gravity-driven processes, probably slumps and debris flows, which moved downslope towards west. Parasound profiles show evidences of such mass movements on present-day seabottom (e.g. diffraction hyperbolae echoes) but also of past-events buried within the contourite sediments. These older debris flows are recognized by semitransparent/transparent acoustic facies and lenticular shape. Keywords: along-slope processes, mass movements, Madeira lower slope, Madeira drift, Central Atlantic 1. INTRODUCTION The knowledge of the sedimentary processes acting on the Madeira Island slope remains scarce. The idea that the deep marine realm was a quiet and steady place changed over the last decades, due to technological improvements. For instance, bottom- current activity is more important than thought before, being testified worldwide by the occurrence of thick contourite drifts. This is the case for instance of Argentina Basin (e.g. Hernández-Molina et al., 2009). The joint occurrence of contourite drifts and several types of mass movement deposits (MMD), such as debris flows and slumps, is recognized independently of the geological and oceanographic settings and at different time-scales (e.g. Bryn et al., 2005). Nevertheless, despite the studies done so far regarding these questions, little is known about the interaction between along-slope and down-slope processes in volcanic islands slopes. While several volcanic islands occur in the Eastern Central Atlantic, the majority of the works have been focused either on large landslides or broad turbidite systems (e.g. Wynn et al., 2000). However, an extensive contourite drift, the Madeira Drift, is located in western lower slope of the Madeira Island (Fig. 1). The Madeira Drift was scarcely studied in the pioneer work of Embley et al. (1978) and remained almost unknown since then. Recently, Hernández-Molina et al. (2011) predicted the presence of contourite drifts on the Madeira lower slope based on numerical modeling of water masses circulation. The present work shows new acoustic evidence of along-slope processes on Madeira lower slope and its association with mass movement processes. 2. DATA AND METHODS The dataset used in this work is multiscale and includes GEBCO bathymetry, multibeam bathymetry, Parasound ecosounder profiles and multichannel reflection seismic profiles (Fig. 1). Multibeam bathymetry was acquired by EMEPC in the scope of 583