Pumice deposits of the Santorini Lower Pumice 2 eruption on Anafi island, Greece: Indications for a Plinian event of exceptional magnitude.

Abstract: Isolated patches of Santorini pumice deposits are analysed from the non-volcanic island of Anafi at a distance of 31–38km east from the centre of the Santorini caldera. The deposits are Plinian fall profiles with a primary thickness at this distance of 1.2–1.5m and MP (maximum pumice) and ML (maximum lithic) diameters of 5 and 4cm, respectively. The characteristic profile sequence of the analysed Anafi deposits corresponds perfectly with the Plinian sequence of the Lower Pumice 2 (LP2) profiles on Thera, the main island of the Santorini group, with the sub-divisions into LP2-A2-1, LP2-A2-2 and LP2-A3. Pumice glass chemistry, phenocryst assemblage and the significant content of grey cauliform scoriae make the compositional correlation with the Plinian LP2 eruption of Santorini unambiguous. With the new identification of LP2 deposits on Anafi, together with an ~4–5 times greater thickness in the main axis of dispersal of the proximal Plinian LP2 deposits compared to the Minoan fallout on Thera, the Plinian opening phase of the 172ka LP2 eruption (LP2-A) is regarded by far as the most voluminous of all Plinian eruptive phases on Santorini. [Copyright &y& Elsevier]