The Greek archipelago of Santorini consists of the remains of a powerful volcano. Members of the international IODP expedition "Hellenic Arc Volcanic Field" have now found evidence of one of the largest eruptions ever recorded in the southern Aegean Arc.
Their paper published today in the journal Communications Earth & Environment describes a newly discovered giant pumice deposit sampled from the seafloor at seven coastal sites around the island of Santorini. It shows that the Christiana-Santorini-Kolumbo volcanic field was much more explosive in the distant past than previously thought.
The data suggests that this volcanic field, encompassing over 20 volcanoes primarily underwater, has been historically volatile. Notably, an eruption occurred 3,600 years ago, potentially triggering the collapse of the Minoan civilization. However, recent findings indicate a massive submarine eruption that took place around 520,000 years ago. This eruption resulted in a pumice deposit volume exceeding 90 cubic kilometres and an impressive thickness of up to 150 meters, dwarfing deposits from known historical eruptions.
The team, led by Dr Steffen Kutterolf of the GEOMAR Helmholtz Centre for Ocean Research and Dr Timothy Druitt from the University of Clermont-Auvergne, utilized a variety of methodologies to decipher this eruption. This included micropalaeontology, physical property measurements, and chemical analyses using an electron microprobe. These techniques aided in dating the eruption, estimating the water depth, and analyzing the seafloor's chemical composition and seismic images.
While another eruption of this magnitude is considered unlikely in the near future, understanding the past is crucial for future predictions. The discovery of the submarine pumice deposit, named the Archaeos Tuff, through deep drilling, multidisciplinary shipboard datasets, and marine seismic profiles marks a significant step forward. The finding extends the explosive history of the Santorini volcanic complex and highlights the importance of deep subsea drilling in revealing the secrets of island volcanic arcs, especially in densely populated areas such as the Mediterranean. The detailed findings have been published in the Communications Earth & Environment journal.
More information: Tim Druitt et al., Giant offshore pumice deposit records a shallow submarine explosive eruption of ancestral Santorini, Communications Earth & Environment (2024). DOI: 10.1038/s43247-023-01171-z
Provided by Helmholtz Association of German Research Centres