Tectonic modulation of caldera volcanism on the South Aegean island arc

Authors

• A Metcalfe, Université Clermont Auvergne
• Tim Druitt, Laboratoire Magmas et Volcans, Clermont-Ferrand
• Katharina Pank, Helmholtz Centre for Ocean Research Kiel
• Steffen Kutterolf, Helmholtz Centre for Ocean Research Kiel
• Jonas Preine, University of Hamburg
• Sarah Beethe, Oregon State University
• Axel K. Schmitt, Heidelberg University
• Christian Hübscher, University of Hamburg
• Paraskevi Nomikou, National and Kapodistrian University of Athens
• Thomas A. Ronge, Alfred Wegener Institute - Helmholtz Centre for Polar and Marine Research
• Carole Berthod, CNRS
• Hehe Chen, China University of Geosciences, Beijing
• Shun Chiyonobu, Akita University
• Acacia Clark, University of Tasmania
• Susan DeBari, Western Washington University
• Ralf Gertisser, Keele University
• Raymond Johnston, University of South Florida
• Olga Koukousioura, Aristotle University of Thessaloniki
• Michael Manga, University of California at Berkeley
• Molly McCanta, Tufts University
• Iona McIntosh, Japan Agency for Marine-Earth Science and Technology
• Ally Peccia, Columbia University
• Masako Tominaga, Woods Hole Oceanographic Institution
• Yuzuru Yamamoto, Japan Agency for Marine-Earth Science and Technology
• Adam Woodhouse, University of Texas at Austin
• Alexis Bernard, Université de Pau et des Pays de l'Adour
• Tatiana Fernandez-Perez, Kent State University
• Christopher Jones, University of California at Riverside
• Kumar Batuk Joshi, National Centre for Earth Science Studies
• Günther Kletetschka, University of Alaska Fairbanks

Document Type

Article

Abstract

Many highly hazardous, caldera-forming explosive eruptions occur in extensional tectonic regimes, but the role of lithospheric rifting in modulating caldera volcanism remains enigmatic. IODP Expedition 398 deep-drilled the volcano-sedimentary infills of submarine half-grabens around Santorini caldera on the continental South Aegean Volcanic Arc. Here we use the volcanic tephra archives to produce a high-resolution eruptive chronostratigraphy for Santorini, to ground-truth seismic stratigraphy, and to extract an integrated timeline of volcano-tectonic couplings. The rift basins contain several submarine volcaniclastic megabeds from the caldera-forming eruptions of Santorini and one from the Kos caldera. The thickest megabed succession is < 250,000 yrs old and lies on a seismic reflection onlap surface that records a phase of rapid rifting. Sedimentation lagged behind subsidence during this rifting phase, creating bathymetric troughs. Integrating submarine core-seismic and onland datasets, we propose that rifting may have driven the transition of Santorini from a prolonged state of effusive and minor explosive activity (∼550 – 250 ka) typical of arc stratovolcanoes to one of repeated caldera-forming eruptions (<250 ka). Rapid rifting may have amplified the normal internal dynamics of the magmatic system in three ways, driving the volcano into a sustained, highly explosive state: (1) an increase in the supply of mantle-derived basalt, (2) enhanced shearing, permeability, and melt percolation in the transcrustal magmatic system, and (3) the development of horizontally extensive magma reservoirs. Broadly simultaneous transitions into caldera-forming activity of the widely separated Santorini and Kos Volcanoes suggest that the two magmatic systems are linked by plate-scale lithospheric stresses.

DOI Link

10.1016/j.epsl.2025.119633

Publication Date

2025-12-01

Publication Title

Earth and Planetary Science Letters

Volume

671

ISSN

0012-821X

Acceptance Date

2025-09-06

Deposit Date

2026-10-05

Funding

This research was supported by IODP (participation of shipboard scientists on IODP Expedition 398), IODP France (A.Me and T.D), GEOWARN project contract no: IST-1999- 12310 (P.N.), Seafloor mapping of the Santorini-Amorgos region OCE-1548026 (P.N.), German Research Foundation (DFG) IODP priority programme KU2685/17-1, project number: 527924707 (S.K. and K.P.) and German Science Foundation grant numbers 434763330 and 506199584 (C.H. and J.P.).

Keywords

Caldera, Tectonic modulation, Megabed, Explosive eruption, Thermal runaway, Ignimbrite flare-up

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Metcalfe, A., Druitt, T., Pank, K., Kutterolf, S., Preine, J., Beethe, S., Schmitt, A., Hübscher, C., Nomikou, P., Ronge, T., Berthod, C., Chen, H., Chiyonobu, S., Clark, A., DeBari, S., Gertisser, R., Johnston, R., Koukousioura, O., Manga, M., McCanta, M., McIntosh, I., Peccia, A., Tominaga, M., Yamamoto, Y., Woodhouse, A., Bernard, A., Fernandez-Perez, T., Jones, C., Joshi, K., & Kletetschka, G. (2025) 'Tectonic modulation of caldera volcanism on the South Aegean island arc', Earth and Planetary Science Letters, 671. Available at: 10.1016/j.epsl.2025.119633