Les Foraminifères des carottages holocènes de la plate-forme continentale sarde

Abstract

The object of this work is to present the foraminifera associations found in seven cores of holocoenic period from the continental shelf of southern Sardinia. The percentage of benthos is always definitely greater than 82,5 % . The benthic species are very numerous. There are no extinct species or species which present a paleoclimatic interest. The top-core samples collected from the infralittoral zone present two different associations based on its granulometry (sand and silt). The species most commonly found in sand are : Cibicides lobatulus, Ammonia beccarii, Rosalina globularis, Asterigerinata mamilla, Gavelinopsis praegeri, Buccella frigida granulata, Eponides répandus, Quinqueloculina aspera, etc. The species most commoly found in silt are Rosalina globularis, R. obtusa, Cibicides lobatulus. The presence of Posidonia oceanica may lead to a greater peercentage of some species (i.e. Nubecularia lucifuga, Rosalina bradyï). They may be referred respectively to the biocenose of well calibrated fine sands ("SFBC" of Peres & Picard, 1964) and to the biocenose of the "herbier" of Posidonie ("HP" of Peres & Picard, 1964). The species most commoly found in the top-core samples of the circalittoral zone are Asterigerinata mamilla, Cibicides pseudoungerianus, C. lobatulus, Neoconorbina terquemi, Ammonia beccarii, Spiroplectammina wrighti, etc. The planktonic foraminifera are mostly represented by Globorotalia truncatulinoides, Globigerina bulloides, Globorotalia inflata, Neogloboquadrina pachyderma, Globigerinoides trilobus. The association may be attributed, with great probability, to the biocenose of the coastal detritus ("DC" of Peres & Picard, 1964). Along the cores, the associations present characteristics similar to those of the surface samples.