Received date December 29, 2013; Accepted date December 30, 2014; Published date December 31, 2014
Citation: Alcántara-Carrió J, Albarracín S, Bouzas AF (2015) The Role of the Geological Inheritance in the Present Littoral – Shelf Sedimentary Interactions. J Marine Sci Res Dev 5:155. doi:10.4172/2155-9910.1000155
Copyright: © 2015 Alcántara-Carrió J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Normally, sedimentary processes in the littoral and the shelf (continental or insular shelf) are studied separately. However, there are complex interactions between them that cannot be ignored, because they are not isolated sedimentary environments. On the contrary, the fluxes of energy and materials are continuous between them. These feedbacks occur at the different geological scales, from long (centuries, thousands and millions of years), to medium (years, decades) and short (hours-days) time scale, and each one of these temporal scales has associated its spatial scale [1,2].
At long term, geomorphological evolution of the littoral and shelf is controlled by three factors: sea level oscillations, sediment supply and tectonics. Thus, sea level oscillations generate a continuous alternation of coastal and shelf sedimentary environments, resulting that sediment filling of shelves can be composed in a very significant portion by Pleistocene coastal deposits [3,4] formed during sea level falls, and even continental subaerial deposits [5-7] formed during lowstands.
At short and medium time, littoral – shelf sedimentary interactions are mainly determined by the input of energy from the outer shelf and the supply of sediments, mainly from the coast . Then, they are the two main factors controlling the sedimentary budget and recent geomorphological evolution of both, the littoral and the shelf, at this time scale. However, the three factors acting at long term scale also affect the morphodynamics in the short time, acting as a geological framework or geological inheritance. Thus, for instance, the bathymetric contour of the shelf, result of this geological inheritance, affects to the present hydrodynamic processes in the shelf and littoral, and consequently, it conditions the availability and fluxes of sediments to the beaches and dunes. Therefore, it can be highlighted that the interaction between sedimentary processes in the littoral and the shelf includes also a complex feedback between hydrodynamics and sedimentary processes at the different time scales.
Combined studies at short, medium and long term scales are really useful to determine current source of sediments to the coastal environments, pathways and mechanisms of coastal sediment transport, and impact of human disturbances in the coastal morphodynamics . In summary, sedimentary processes at the different scales are clearly related, and consequently, it is necessary to know the sedimentary processes at the long term scale to a correct understanding of the sedimentary processes in the short and medium term scale. The geological inheritance has a very important influence in present hydrodynamics and morphodynamics of both, coastal and shelf environments, and consequently in their sedimentary interactions. Unfortunately, this assumption is frequently ignored in coastal engineering studies.