COMMON AND RARE LOWER PLIOCENE AGGLUTINATED FORAMINIFERS OF PIEDMONT (NORTHWESTERN ITALY): DISTRIBUTION, TAXONOMY AND PALEOENVIRONMENT

Agglutinated foraminiferal taxa from five stratigraphic sections and eightheen small outcrops of Lower Pliocene deposits were quantitatively analyzed for paleoenvironmental purposes. The studied area is located in Piedmont, northwestern Italy, and includes the northeastern Monferrato, the southern margins of the Turin Hill, the Astigiano, the Albese and part of the Langhe. Studied samples were mainly collected in the marine Argille Azzurre (AA) Formation, and cover a time interval ranging from the MPl1 zone to the MPl4a subzone in the Pliocene Mediterranean Foraminiferal Zonation. Most of the agglutinated assemblages are dominated, or exclusively made, by calc-agglutinated infaunal species of elongated tapered or subcylindrical shape, mainly represented by Bigenerina nodosaria and Martinottiella communis. The deep-water infaunal Cylindroclavulina rudis, Eggerella bradyi and Martinottiella perparva characterized the open-sea basinal facies deposited in the central part of the Piedmont region during the earliest Pliocene. These taxa progressively decreased in abundance until to disappear, and were replaced in the upper silty succession by shelf taxa, dominated by Bannerella gibbosa and Textularia aciculata. In particular, T. aciculata showed its highest abundances in infralittoral to shallow circalittoral muddy sediments of probable fluvial origin, widespread in the Astigiano area, and could be suggested as a typical species of shallow marine delta deposits. Among the 42 agglutinated species here determined, Cyclammina cancellata and Reophax scorpiurus were seldom reported in previous works, Ammobaculites agglutinans, Ammoscalaria spp., Cribrostomoides subglobosus subglobosus, Haplophragmoides canariensis, Psammosphaera spp., and Psammolingulina papillosa were not previously found. The occurrence of these rare taxa could be the proxy of particular sea-floor conditions during the MPl3 zone, characterized by a locally active bottom circulation and mesotrophic waters

FORAMINIFERI ATTUALI IN SEDIMENTI INFRALITORALI E CIRCALITORALI A NORD DI MESSINA (SICILIA, ITALIA)

Quantitative micropaleontological analyses are carried out on eleven samples from inner neritic to outer neritic sands of the sicilian coast, north of Messina. Three groups are described: 1) fossil taxa, mainly from Pliocene sediments in the terrigenous discharges, 2) live and 3) dead specimens of recent species. The distribution of benthic specimens seems largely controlled by the amounts and the sites of terrigenous sediments deposition and by the patchiness of algal biocoenoses. Percentages of live forms are higher in the northern samples, less affected by reworked or winnowed sediments: sessile foraminifers (Glabratellidae, Discorbidae) are dominant. On the contrary, dead specimens of miliolids, elphidiids, rare rotaliids ecc. are common in the thanatocoenoses of the southern and deeper samples

CONTRIBUTI ALLO STUDIO DEL NEOGENE DELLE LANGHE SUD-OCCIDENTALI (MONDOVI')

The Miocene-Pliocene sedimentary succession of southwestern Piedmont Tertiary Basin, outcropping near Mondovì, is here briefly described. Planktonic and benthic foraminifers are analyzed with the aim to date the sediments and to investigate their paleoenvironmental conditions. In the southern and western outcrops, marls and silty marls from the N7 Zone (Late Burdigalian) to the N10 Zone (Serravallian) seem to testify a continue sedimentation at an upper epibathyal depth. A gap could separate these sediments from the overlying silty marls, attributable to the N16 Zone (Tortonian) of outer neritic or upper epibathyal zone. In the northeastern outcrops, clayey and sandy marls seem to be sedimented during the Early Pliocene in the outer neritic or upper epibathyal zone. Coarser sediments (silts, silty sands, sandy gravels) yield outer neritic to inner neritic foraminiferal associations, probably Pliocene in age. They might be more recent than the Early Pliocene marls or may represent heteropic facies