Localisation et organisation interne de récifs coralliens immatures sur un cône alluvial du Quaternaire ancien de la Mer Rouge (Sud de l'Egypte)

Localisation and internai organisation of immature coral reefs on an Early Quaternary alluvial fan, NW Red Sea. Egypt. The excellent quality of southern Egypt outcrops enables a precise study of the initial stages of Early Quaternary reef installation and development during a brief period of relative sea level high. The reefs grew on an alluvial fan whose coarse constituents were reworked by littoral hydrodynamics recorded by beach gravels, boulder concentrations and a sand spit. Tectonic influence is expressed by the instability of relative sea level and by small fautls which cut the initial reefs and their terrigenous substratum : alluvial fan and sand spit, the later affected by synsedimentary lithification. Finally, a lowering of relative sea level is indicated by seawards migration of reef growth resulting in a more classical, fringing-type reef whose growth is displaced progresively towards the South as a result of long-shore terrigenous supply. Architecture and biologic composition of the successive constructions are interpreted as the result of local hydrodynamics, coarse sediment supply and tectonic uplift or drawning.Au sud de l'Egypte, la qualité remarquable des affleurements permet d'analyser précisément les conditions de l'installation et du développement de récifs quaternaires, pendant la durée limitée d'un haut niveau marin, sur le front d'un cône modérément grossier remanié par la dynamique littorale : plages à galets, concentration de blocs, flèche littorale sableuse. L'influence de la tectonique se manifeste par l'instabilité du niveau marin relatif et par des failles affectant les premiers récifs aussi bien que leur substratum terrigène : cône et flèche sableuse lithifiée précocément. Enfin, une baisse relative du niveau marin décale la zone de croissance récifale vers le large et induit une construction plus classique, de type récif frangeant, progressivement repoussée vers le sud par les apports terrigènes de la dérive littorale.Plaziat J.-Cl., Purser Bruce Harold, Soliman M. Localisation et organisation interne de récifs coralliens immatures sur un cône alluvial du Quaternaire ancien de la Mer Rouge (Sud de l'Egypte). In: Géologie Méditerranéenne. Tome 16, numéro 2-3, 1989. genèse, diagenèse et intérêt économique des récifs. Actes du colloque tuniso-français de sédimentologie-récifs (Tunis, 26-29 mai 1988) pp. 41-59

Correlation of messinian carbonate platforms

Esteban M., Clauzon Georges, Cornée Jean-Jacques, Cunningham K., Ferrandini Jean, Franseen E., Görür Naci, Guieu Gérard, Grasso M., Hôffling R., Meyers N., Muller J., Pedley Martyn, Plaziat J.-Cl., Suballyuva A., Suc Jean-Pierre, Valleri G., Van buchem Frans S. P. Correlation of messinian carbonate platforms. In: Géologie Méditerranéenne. Tome 21, numéro 1-2, 1994. Récifs et plates-formes carbonatées miocènes de Méditerranée / Miocene reefs and carbonate platforms of the Mediterranean. Interim colloquium R.C.M.N.S. (Marseille 3-6 mai 1994) sous la direction de Jean-Paul Saint-Martin et Jean-Jacques Cornée. pp. 159-163

Colonization and shift of mollusc assemblages as a restoration indicator in planted mangroves in the Philippines

We compared the mollusc assemblages of planted mono-specific Rhizophora mangroves of known different ages. As forest age increased, there was a shift in species composition, abundance and biomass of mollusc assemblages for all faunal types (infauna, epifauna and arboreal fauna). This shift was correlated with the changes in vegetation (increasing forest cover and above-ground biomass) and sediment characteristics (increasing organic matter and decreasing sand content). Some species dominate in young plantations (\u3c10 years old; Pirenella cingulata) and in intermediate plantations (10–15 years old; Nerita polita), while other species only occur in mature plantations and natural mangrove stands (\u3e15 years; Terebralia sulcata, Nerita planospira). The two former groups of species are mostly species of infaunal and epifaunal habitats, while the latter group is mainly composed of arboreal species. The shift in mollusc species composition and dominance may serve as a useful indicator of restoration patterns in planted mangroves