Chevillon Christophe, Yeo G., Di Matteo A. (1996). Sediment constituents in the Great Astrolabe Reef lagoon (Fiji). In :
The Great Astrolabe Reef lagoon (Fiji) : results of the french-fijian ASTRO expedition. Papeete : ORSTOM, p. 11-16. (Océanographie.Notes et Documents ; 46). ISSN 0755-3412.
Titre du document
Sediment constituents in the Great Astrolabe Reef lagoon (Fiji)
Année de publication
1996
Type de document
Partie d'ouvrage
Auteurs
Chevillon Christophe, Yeo G., Di Matteo A.
In
The Great Astrolabe Reef lagoon (Fiji) : results of the french-fijian ASTRO expedition
Source
Papeete : ORSTOM, 1996,
p. 11-16 (Océanographie.Notes et Documents ; 46). ISSN 0755-3412
Sediments of the Great Astrolabe Reef lagoon were investigated using a Smith-McIntyre grab during the joint Fijian-French ASTRO cruise, in april 1994. This preliminary paper focused on carbonated biophase, which was studied through skeletal composition of 25 sediment samples regularly spaced in the lagoon. Counting and identification of the biogenic debris were achieved for each sample on 13 size fractions (3.98, 3, 2, 1, 0, -1, -1.32, -2, -2.32, -3, -3.32, -4 and -4.32 phi). The results indicates that the main constituents of the carbonated biophase of the lagoon are, in order of importance, Halimeda plates, foraminifers and molluscs. The lagoon as a whole, is characterized by a HALIFOR biofacies and a HaliForPel sub-facies (Halimeda-Foraminifers-Pelecypods). Three main types of biofacies are found : Halimeda biofacies (HALIMOL and HALIFOR), a foraminifer biofacies (FORAMOL) and molluscs biofacies (MOLHAL and MOLFOR). Coral reefs represent only a small part among the producers of lagoon sediments (7th rank). The excellent state of preservation of the bioclasts suggests a modern or recent sedimentation and a low impact of the hydrodynamic agents at the bottom level. The absence of lithoclasts in the sand fraction indicate a limited terrigenous influence. (Résumé d'auteur)
