New Ice-Core Evidence Challenges the 1620sBCage for the Santorini (Minoan) Eruption

Determining a reliable calendrical age of the Santorini (Minoan) eruption is necessary to place the impact of the eruption into its proper context within Bronze Age society in the Aegean region. The high-resolution record of the deposition of volcanically produced acids on polar ice sheets, as available in the SO42−time series from ice cores (a direct signal), and the high-resolution record of the climatic impact of past volcanism inferred in tree rings (a secondary signal) have been widely used to assign a 1628/1627BCage to the eruption. The layer of ice in the GISP2 (Greenland) ice core corresponding to 1623±36BC, which is probably correlative to the 1628/1627BCevent, not only contains a large volcanic-SO42−spike, but it contains volcanic glass. Composition of this glass does not match the composition of glass from the Santorini eruption, thus severely challenging the 1620sBCage for the eruption. Similarly, the GISP2 glass does not match the composition of glass from other eruptions (Aniakchak, Mt. St. Helens, Vesuvius) thought to have occurred in the 17th centurybcnor does it match potential Icelandic sources. These findings suggest that an eruption not documented in the geological record is responsible for the many climate-proxy signals in the late 1620sBC. Although these findings do not unequivocally discount the 1620sBCage, we recommend that 1628/1627BCno longer be held as the “definitive” age for the Santorini eruption.