Unveiling the Volcanic History of Ancient Pompeii (Italy): New Insights from the Late Pleistocene to Holocene (Pre-79 CE) Stratigraphy

Abstract

Many volcanological and geoarchaeological studies in the ancient city of Pompeii (Italy) have been devoted to the 79 CE Plinian eruption of Vesuvius, which sealed the city under a thick pyroclastic sequence. Only fragmentary information exists regarding the stratigraphy of the volcanic sediments sandwiched between the 79 CE street level and the volcanic rocks that form the geological framework of the hill on which Pompeii was built, which constitutes the “Pompeii bedrock”. The stratigraphic survey of twenty-one trenches throughout the city, coupled with a geochemical characterization, highlighted that the pre-79 CE stratigraphy includes at least eight late Pleistocene to Holocene tephra layers. Six eruptions were sourced from Somma–Vesuvius (Pomici di Base, Mercato, AP1 to AP4) and two originated from Campi Flegrei (Neapolitan Yellow Tuff and Soccavo 4). The Pompeii bedrock is the product of local vents, the last activity of which possibly shortly predates the 22 ka Pomici di Base eruption. From a geoarchaeological perspective, a relevant result is the absence of the 3.9 ka Avellino tephra in all trenches. This evidence, along with the reappraisal of the stratigraphy of the nearby archaeological site of S. Abbondio, suggests that the Avellino eruption possibly only marginally affected the Pompeii area during the Early Bronze Age.