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

Abstract

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

Sandy contourite drift in the late Miocene Rifian Corridor (Morocco): Reconstruction of depositional environments in a foreland-basin seaway

“…When the bottom current was weak, secondary processes such as tidal currents or internal tides may also have become more influent on the depositional system (Shanmugam, 2006;Rebesco et al, 2014). In the Gulf of Cadiz contourite system, tides become the dominant process on the surface of channel-fills, or during periods of lateral (down-or upslope) migration of the current (Stow et al, 2013;Hernández-Molina et al, 2016b).…”

The role of Internal Solitary Waves on deep-water sedimentary processes: the case of up-slope migrating sediment waves off the Messina Strait

“…Our findings represent a quantitative study on the role of ISWs for coarse-grained sediment transport in the deep sea that may lead to a better understanding of sedimentary processes and seafloor evolution, which is critical for geohazard assessment538394041. Although the northern entrance of the Messina Strait is morphologically peculiar, we believe that ISW-induced sand waves would occur worldwide and that they have not yet interpreted in this way.…”

“…We therefore demonstrate that this kind of sand waves can be formed by ISWs, so providing a case study to recognize and quantify hydrodynamic drivers for a specific seafloor morphology. This may help to estimate flow conditions from seafloor mapping, an information of large environmental and engineering relevance3839.…”

Offshore Geological Hazards: Charting the Course of Progress and Future Directions

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