Interpretazione paleoambientale di microifaune a foraminiferi nel Pleistocene inferiore di Capo Milazzo (Sicilia)

Abstract

The present study deals with planktonic and benthonic Foraminifera of Early Pleistocene age from 6.5-7 m thick clayey-sandy marls outcropping at Punta Mazza (Capo Milazzo, Sicily). A climatic curve constructed by summing the percentages of warm water indicators (Globigerinoides ruber, G. sacculifer, G. trilobus, Globorotalia truncatulinoidcs excelsa, Hastigerina siphonifera, Orbulina universa), with positive values, and the percentages of cold water indicators (Globigerina bulloides, G. quinqueloba, Globorotalia scitula, Neogloboquadrina pachyderma), with negative values, shows two short warm intervals separated by a longer cold interval; the upper part of the section seems to be deposited in a period characterized by climatic instability. Benthic Foraminifera suggest deposition in the upper epibathyal zone. The percentages of all benthic species (in a total of about 300 specimens in each sample) were used to calculate the faunal diversity (Benthic Foraminiferal Number = BFN), expressed as number of benthic specimens/gram of sediment, the faunal diversity expressed as number of specimens/number of species and the specialization degree, expressed as cumulative percentages of the five most abundant taxa. The 50 most frequent benthonic species were elaborated with Cluster Analysis and reduced to dendrograms showing similarity between the taxa and between the samples. The lower part of Punta Mazza section is characterized by sandy marls and by the presence of inner-outer neritic species; the upper part shows silty-clayey sediments, with deeper and/or cold taxa. The Punta Mazza marls can be compared with upper epibathyal marls of the surrounding area; they can partially be correlated to the lower part of the Rometta (Messina, Sicily) marls (Early Pleistocene), but are older than Lazzaro (Reggio Calabria, Calabria) ones (Early to Middle Pleistocene).