Stratigraphic approach to geological mapping of the late-Quaternary volcanic island of Lipari (Aeolian archipelago, Southern Italy).

Geological mapping of the island of Lipari at a 1:10,000 scale is performed by adopting a stratigraphic approach based on the integrated use of lithostratigraphic units, lithosomes, and unconformity-bounded units (UBU). This approach allows the geological peculiarity of this volcanic area to be reproduced through documenting and interpreting the different rock types (using lithostratigraphic units), and defining the geometry of rock bodies (using lithosomes), or highlighting unconformities in the volcano-sedimentary architecture (using UBUs). In particular, by concentrating on accurate tephrostratigraphy and deposits formed during periods of prolonged volcanic quiescence (e.g. marine deposits and epiclastic products), UBUs provide the main stratigraphic constraints at regional level. Two first-order unconformities (UI and UII), represented by surfaces of erosion bounding marine deposits emplaced during marine oxygen-isotope stage (MIS) 5, can be correlated across most of the Aeolian archipelago. Furthermore, four second-order and seven third-order unconformities represented by erosion and non-deposition surfaces formed during main periods of dormancy 2 or minor sea-level fluctuations of MIS 5 are introduced. The reconstructed unconformitybounded stratigraphy, together with other rock-stratigraphic units, provides an effective reconstruction of the geological evolution of Lipari, ranging between ca. 220 ka and the present time, as the result of the interplay between volcanic activity of local and external provenance, sea-level fluctuations, and regional fault systems. In this framework, Lipari’s eruptive history encompasses five successive eruptive epochs characterized by distinctive centres of eruption (eastwards shifting), eruption type (from mainly strombolian to hydromagmatic), and chemical composition (from calcalkaline basalt-andesite to high-K calcalkaline rhyolite).