Oceanographic processes and morphosedimentary products along the Iberian margins: A new multidisciplinary approach

Special issue The contourite log-book: significance for palaeoceanography, ecosystems and slope instability.-- Hernández-Molina, Francisco J. ... et al.-- 30 pages, 19 figures, 1 table, supplementary data https://dx.doi.org/10.1016/j.margeo.2015.12.008

Our understanding of bottom-currents and associated oceanographic processes (e.g., overflows, barotropic tidal currents) including intermittent processes (e.g., vertical eddies, deep sea storms, horizontal vortices, internal waves and tsunamis) is rapidly evolving. Many deep-water processes remain poorly understood due to limited direct observations, but can generate significant depositional and erosional features on both short and long term time scales. This paper represents a review work, which describes for the first time these oceanographic processes and examines their potential role in the sedimentary features along the Iberian continental margins. This review explores the implications of the studied processes, given their secondary role relative to other factors such as mass-transport and turbiditic processes, and highlights three major results: a) contourite depositional and erosional features are ubiquitous along the margins, indicating that bottom currents and associated oceanographic processes control the physiography and sedimentation; b) the position of interfaces between major water masses and their vertical and spatial variation in time specifically appears to exert primary control in determining major morphologic changes along the slope gradient, including the contourite terraces development; and c) contourites deposits exhibit greater variation than the established facies model suggests. Therefore, a consistent facies model however faces substantial challenges in terms of the wide range of oceanographic processes that can influence in their development. An integrated interpretation of these oceanographic processes requires an understanding of contourites, seafloor features, their spatial and temporal evolution, and the near-bottom flows that form them. This approach will synthesize oceanographic data, seafloor morphology, sediments and seismic images to improve our knowledge of permanent and intermittent processes around Iberia, and evaluate their conceptual and regional role in the margin's sedimentary evolution. Given their complexes, three-dimensional and temporally-variable nature, integration of these processes into sedimentary, oceanographic and climatological frameworks will require a multidisciplinary approach that includes Geology, Physical oceanography, Paleoceanography and Benthic Biology

This contribution is a product of the IGCP-619 and INQUA-1204 projects, and is partially supported through the CTM 2008-06399-C04/MAR (CONTOURIBER); CTM 2012-39599-C03 (MOWER); CTM 2010-21229/MAR projects and MARUM project GALIOMAR, as well as the Continental Margins Research Group (CMRG) at Royal Holloway University of London (UK).

Peer Reviewed