Chrono-stratigraphy of the youngest (last 1500 years) rhyolitic eruptions of Lipari (Aeolian Islands, Southern Italy) and implications for distal tephra correlations

The youngest (last 1500 years) volcanic eruptions of Lipari, within the Aeolian Archipelago, produced the prominent pumice cone of Monte Pilato and the obsidian lava flows of Rocche Rosse and Forgia Vecchia, concentrated in the north-eastern sector of the island as well as highly dispersed white-coloured, fine-grained tephra layers of rhyolitic composition in terrestrial and marine settings on the regional scale. Here we describe in detail the stratigraphy of pyroclastic successions and lava flows erupted by different vents - Monte Pilato, Forgia Vecchia, Lami, and Rocche Rosse - combining field observations, sedimentological characteristics of the tephra deposits, and major and trace element compositions of the volcanic glass. All the pyroclastic materials consist of aphyric pumice lapilli and ash with a largely homogeneous rhyolitic composition. The Monte Pilato and Forgia Vecchia deposits primarily consist of highly vesicular pumice fragments and subordinate obsidian clasts, whilst Rocche Rosse and Lami are characterized by moderately vesicular juvenile fragments with a more significant fraction of obsidian. The Lami tephra also contains peculiar pumice clasts with a fibrous texture and breadcrust bombs.

Stratigraphic relationships, and paleomagnetic and 14C ages of the lava and pyroclastic deposits are combined with the archaeological information and historical reports, enabling us to provide an accurate chrono-stratigraphic framework for the youngest eruptions of Lipari. Following the 8th century CE eruption of Monte Pilato, which produced a pumice cone and a obsidian lava flow, activity resumed in the second half of 13th century CE with the explosive eruption of Forgia Vecchia that culminated in the emission of a bilobate obsidian lava flow. This eruption was shortly followed by the explosive eruptions of Lami and Rocche Rosse, the latter concluded with the emission of the widely renowned obsidian lava flow.

By integrating stratigraphy and geochemistry of tephra deposits with a new chronological scheme, our work facilitates the refinement of proximal-to-distal correlation of Lipari's rhyolitic tephra in continental marine environments of the central Mediterranean area in the last 1500 years. A fine-grained, rhyolitic ash found on Stromboli (~40 km NE from Lipari) has an origin from the Monte Pilato and thus, constrains tephra dispersion towards the NE. Very similar ash beds dispersed southwards and interlayered within the near-source deposits of La Fossa, Vulcano island (~10 km from Lipari) exhibit features that are consistent with the younger activities of the Rocche Rosse eruption. A possible link between previously identified rhyolitic ash layers identified in marine cores of the Ionian Sea and the Forgia Vecchia eruption are postulated, although the age and textural characteristics of these distal tephra are not univocal in indicating a correlation to either Monte Pilato or Forgia Vecchia.