Artículos (Ciencias del Mar)
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Examinando Artículos (Ciencias del Mar) por Autor "Alcántara-Carrió, J"
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Ítem Combined beach - inner shelf erosion in short and medium term (Maspalomas, Canary Islands)(Faculty of Geology, Martí i Franquès, 2012-12-01) Fontán, A; Alcántara-Carrió, J; Correa-Arango, Ivan D.; Universidad EAFIT. Departamento de Geología; Ivan D. Correa-Arango (icorrea@eafit.edu.co); Ciencias del MarThe analysis of the accurate topo-bathymetric digital elevation model (DEM), the cartography of the submarine sedimentary cover and the monitoring of short (seasonal) and medium-term (2000-2009) morphological changes have permitted depicting the erosional trend in the short and medium-term of the Maspalomas sedimentary system. Short-term analysis showed intense sedimentary fluxes between the beaches and the inner shelf, and sedimentary exchanges with other sectors of the inner shelf, while the steep slope inner shelf fronting La Bajeta cape was identified as a sink area. In the medium-term the sediment budget showed high erosion of the supratidal and intertidal sectors of the beaches due to storm waves in the 2005-2006 winter, followed by accretion over the next four years, but which did not reach the initial sedimentary state. The inner shelf and subtidal sector of the beaches showed negative budgets in the short and medium-term. Interannual variability of the wave and wind regimes determines decadal beach erosion-accretion cycles, while long-term climatic change, evidenced at the study area by a decrease of trade winds and NE wave intensity in 2005, is expected to produce a possible increase of erosion at the El Inglés inner shelf and consequently a decrease in sediment inputs to the El Inglés beach and Maspalomas dune field. Finally, the influence of the geological heritage is depicted by the Fataga gully’s control of the present coastal morphology, and by the island relief control of the wind, waves and current directions in the study area.Ítem Historical and recent shore erosion along the Colombian Caribbean Coast(COASTAL EDUCATION & RESEARCH FOUNDATION, INC., 2005) Correa-Arango, Ivan D.; Alcántara-Carrió, J; González R., D.A; Universidad EAFIT. Departamento de Geología; Ivan D. Correa-Arango (icorrea@eafit.edu.co); Ciencias del MarThe analysis of historical charts, aerial photographs, satellite images and fieldwork provides a general picture of the magnitudes, rates and some of the possible causes of the main shoreline changes occurred along the littoral since 1794 until present. Net littoral accretion took place mostly on localized deltaic zones, but cliff and beach retreat has been by far the dominant trend in this coast, particularly along the coastline to the south of Sierra Nevada de Santa Marta. Data concerning the Guajira Peninsula and Sierra Nevada de Santa Marta shores suggest a coastline retreat of 20-30 m in the last century, while for the southern Caribbean, between the Magdalena delta and the Gulf of Urabá, accurate charts of XVIII-XIX centuries evidence littoral retreat up to 12 km and maximum rates of erosion up to 40 myr-1 at some areas. Shore erosion and consequent flooding along the Caribbean coast of Colombia had induced important land losses, both in non-developed and developed areas, and is impacting severely the infrastructure of all the inhabited littoral sectors. Available data for the most critical areas demonstrates that natural instability and/or pre-existing erosive trends are facilitated by soft lithologies and were dramatically accelerated in the last eight decades by intensive human interventions, including the chaotic building up of hard rock coastal defenses, the diversion of low river courses and the intensive beach and river sand extraction.