Investigations on the S\u2019Ozzastru section from the northern part of the Mt Albo area (central-eastern
Sardinia, Italy) for integrated litho- bio- and chemostratigraphy allowed the identification of the Valanginian Weissert
Oceanic Anoxic Event (OAE), testified by a positive carbon isotope excursion (CIE). The section, which represents
the deepest-water succession of the Valanginian in Sardinia, is composed of the Schiridd\ue8 Limestone followed by
the Siniscola Marl, both proposed as new lithostratigraphic units. The presence among the ammonites of Busnardoites
campylotoxus allows the attribution of the Schiridd\ue8 Limestone to the upper Lower Valanginian Inostranzewi Zone of
Reboulet et al. 2014. Further characterization of this unit was not possible since it is barren/almost barren of nannofossils.
The Siniscola Marl can be ascribed to the lower Upper Valanginian on the basis of the ammonite fauna indicating
the Verrucosum Zone, and of the nannofossil content suggesting the Zone NK3. The carbon isotope record in
the Siniscola Marl is characterized by a positive excursion with values up to 2.98 \u2030. In the nannofossil assemblages,
nannoconids are not particularly abundant and are found, among others, together with C. oblongata, D. lehmanii, and
pentaliths. The scarcity of nannoconids is regarded as a biostratigraphic support for the identification of the Weissert
OAE, as it possibly reflects the \u201cnannoconid decline\u201d interval which characterizes this event. The end of the Weissert
OAE CIE is not recorded probably because of suppression of the upper part of the succession for tectonic causes