Age of the Valle del Bove formation and chronology of the post-collapse flank eruptions, Etna volcano (Italy)

The Valle del Bove is a profound and wide scar on the east Etna flank witnessing the Holocene main volcanotectonic
event of the volcano, frequently invaded by lava flows during the last centuries. The Valle del Bove
slope failure produced the Milo debris avalanche deposit on the lower east flank that is partially covered by the
Mongibello lavas and a pyroclastic succession. In this paper, we constrain for the first time the age of the Milo
debris avalanche deposit and the overlying lava succession exposed at three quarries recently caved at the valley
mouth through a multidisciplinary approach integrating stratigraphic and petrographic analyses, 14C, and
paleomagnetic dating. In particular, 14C age determinations of the Milo debris avalanche deposit indicate that the
initial stage of the catastrophic flank collapse of the Valle del Bove occurred at 7478–7134 BCE during the
Mesolithic age. Conversely, the main portion of the lava succession filling the valley floor emplaced after the sub-
Plinian picritic eruption occurred at 2579–2278 BCE (FS tephra layer) consistently with the increasing occurrence
frequency of flank eruptions documented in the geological record of Etna during the past 4000 yrs.
Paleomagnetic dating highlighted that in the study area the sub-Plinian eruption was followed by two quasicontemporaneous
flank eruptions during the Late Copper age (2600–2400 BCE), whereas other two flank
eruptions occurred during Greek-Roman and Medieval ages. These results have relevant implications on the
stratigraphy and evolution of Etna, particularly on the Valle del Bove initial collapse and the relative
emplacement of the Chiancone detritic-alluvial sequence.