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Article Dans Une Revue Géomorphologie : relief, processus, environnement Année : 2008

Relative roles of structure, climate, and of a tsunami event on coastal evolution of the Falkland Archipelago

Résumé

The relative importance of structural or climatic controls on coastal evolution is debatable. The Falkland Archipelago (52° S – 59° W) comprises many small scattered islands. They correspond to an appalachian folding in various sandstones and many bays are located in synclines. Differential erosion explains the local scale location of headlands and embayments. Faultlines are associated with high cliffs. All the islands are exposed to broadly the same wind and wave climate. Dominant westerlies impart a strong sediment flux down drift (i.e. West to East), displaying, at a local scale, a source to sink distribution of coastal features. A tsunami deposit has been identified in the Falkland Islands, and its relative role upon the geomorphic evolution of the coast is discussed and compared to structural and climate controls. The tsunami hit the north-western islands but not the southern ones. A north-south comparison shows that the tsunami has disrupted some key elements of the sedimentary flux leading to areas of non deposition and local reversal of the sediment cell direction (i.e. East to West). A few 14C dates indicate that the tsunami probably occurred about 1500 radiocarbon years BP. Today its impacts are slowly disappearing and a“usual” West to East drift-controlled behaviour is redeveloping.

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Géographie

Dates et versions

hal-00319896 , version 1 (09-09-2008)

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Citer

Hervé Regnauld, Olivier Planchon., Jales R. Goff. Relative roles of structure, climate, and of a tsunami event on coastal evolution of the Falkland Archipelago. Géomorphologie : relief, processus, environnement, 2008, 14 (1), pp.33-44. ⟨10.4000/geomorphologie.5383⟩. ⟨hal-00319896⟩
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