Explosive volcanic activity in Central-Southern Italy during Middle Pleistocene: A tale from tephra layers of the Acerno basin

The cored succession of the Acerno basin, a tectonic palaeolake located in the southern Apennines (Italy), represents a key point of the Italian tephrostratigraphic network for the Quaternary. Trace element and isotope (⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd) data have been acquired on bulk rock, glassy groundmass and separated minerals (feldspar and pyroxene phenocrysts) from twenty-one tephra layers, dated between ∼570 and 470 ka, embedded in the lacustrine sediments of the basin. The already available major element compositions have been here combined with the newly acquired data. The whole dataset provides a full geochemical characterization of the tephra that strengthens and improves previous attempts to identify their volcanic sources and potential correlatives. In this context, several previously proposed correlations among distal archives have been here confuted. The geochemical fingerprints highlight that the volcanic record preserved in the Acerno lacustrine succession can be attributed to the explosive activity of the Roccamonfina, Colli Albani, Sabatini, Pontian islands (Latium region, Central Italy) and the Neapolitan Volcanic Area (Campania region, South Italy), providing new insights to enhance the current knowledge on the Middle Pleistocene volcanic record in Italy. Moreover, tephra attributions suggest still unknown eruptive activity of such volcanoes during the Quaternary. From this perspective, our study testifies how difficult it is to precisely correlate different geological archives even in a very short time interval. Such a difficulty arises from a large number of volcanic events concentrated in a relatively short time span, with products of similar chemical composition, and from the incomplete characterization of the successions in proximal outcrops. A thorough reconstruction of the eruptive history of these volcanic complexes requires a wider and denser study of distal archives, alongside further investigations in proximal areas.