Pliocene foraminifera of Piedmont (north-western Italy): a synthesis of recent studies

Abstract

A synthesis of recent biostratigraphical and palaeoenvironmental studies on foraminifera assemblages of
the Piedmont Pliocene (north-eastern Monferrato, Astigiano, Langhe and Monregalese) is discussed. In the
region, biozone MPl1 is documented by typical Sphaeroidinellopsis assemblages only in its central area. Rich
and diversified assemblages of MPl2 biozone, with Globorotalia margaritae Bolli & Bermudez, and MPl3
biozone, with G. margaritae and G. puncticulata (Deshayes), are indicative of the upper epibathyal zone,
and suggest palaeoenvironmental conditions similar to those of coeval pelagic successions of Sicily and the
Tyrrhenian Sea. Already along biozone MPl3, and chiefly biozone MPl4, with G. puncticulata, less diversified
assemblages become more widespread, indicating shelf palaeoenvironments, subject to heavy transport of
displaced foraminifera from more inner neritic zones. In the study area most inner neritic and shallow outer
neritic microfaunas are devoid of biostratigraphic markers; only few silty sediments yield Bulimina basispinosa
Tedeschi & Zanmatti and Globobulimina ovula (d’Orbigny), reported from the Middle Pliocene, and can be
correlated to the MPl5 biozone.