Titre :

Contrasting sand beach morphodynamics in a mud-dominated setting: Cayenne, French

Auteur(s) :

Anthony, E. J. [Auteur]
Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement [CEREGE]
Dolique, F. [Auteur]
Université de Guyane [UG]
Université des Antilles [UA]
Gardel, Antoine [Auteur]
Université du Littoral Côte d'Opale [ULCO]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Marin, Denis [Auteur]
Université du Littoral Côte d'Opale [ULCO]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]

Titre de la revue :

Journal of Coastal Research
Special Issue 64: PROCEEDINGS OF THE 11th INTERNATIONAL COASTAL SYMPOSIUM ICS2011

Pagination :

30-34

Éditeur :

Coastal Education and Research Foundation

Date de publication :

2011

ISSN :

0749-0208

Mot(s)-clé(s) en anglais :

beach rotation
Amazon mud supply
mud banks
longshore drift
muddy beach

Discipline(s) HAL :

Planète et Univers [physics]/Sciences de la Terre/Océanographie

Résumé en anglais : [en]

The 15 km-long bedrock promontory of Cayenne, French Guiana, comprises three headland-bound fringing sandy beaches (>2< 5 km-long and referred to as type 1 beaches), and numerous, more or less highly embayed, short ...
Lire la suite >The 15 km-long bedrock promontory of Cayenne, French Guiana, comprises three headland-bound fringing sandy beaches (>2< 5 km-long and referred to as type 1 beaches), and numerous, more or less highly embayed, short pocket beaches (0.1-1 km-long, type 2 beaches) exhibiting variable morphodynamic changes in response to mud banks migrating from the Amazon. Aerial photographs, satellite images and field studies of these mudaffected beaches show alternations between 'mud-bank' phases, when mud banks migrating northwestwards from the mouth of the Amazon River attain the Cayenne area, leading to extensive wave energy dissipation, 'inter-bank' phases, characterised by relative scarcity of mud and enhanced wave activity, and transitions between these two phases. During inter-bank phases, higher incident waves lead to the cleanout of mud from the intertidal beach and induce 'normal' beach morphodynamics. Transitional phases are associated with the variable presence of mud on these beaches, and result in the largest morphodynamic variability on the longer type 1 beaches. These beaches undergo alternations in longshore drift direction that are associated with a rare form of beach rotation induced by wave-mud interaction. These phases are associated with short-lived sand bed collapse features affecting the intertidal beach profile. Profile changes on type 2 beaches are much weaker, and are basically cross-shore, with little or no evidence of longshore sand drift, because of the poor propensity for development of longshore gradients in wave energy in these short embayed beaches. The presence of mud alters the behavioural patterns of beaches on the Amazon-influenced coast of South America, which is normally influenced by seasonal changes in wave energy due to trade-wind activity. ADDITIONAL INDEX WORDS: Amazon mud supply, mud banks, longshore drift, muddy beach, beach rotationLire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Collections :

• Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL