Explosive eruptive history of Pantelleria, Italy : repeated caldera collapse and ignimbrite emplacement at a peralkaline volcano

Jordan, Nina; Rotolo, Silvio; Williams, Rebecca; Speranza, Fabio; McIntosh, William; Branney, Michael J.; Scaillet, Stéphane

Abstract

A new, pre-Green Tuff (46 ka) volcanic stratigraphy is presented for the peralkaline Pantelleria Volcano, Italy. New ⁴⁰Ar/³⁹Ar and paleomagnetic data are combined with detailed field studies to develop a comprehensive stratigraphic reconstruction of the island. We find that the pre-46 ka succession is characterised by eight silica-rich peralkaline (trachyte to pantellerite) ignimbrites, many of which blanketed the entire island. The ignimbrites are typically welded to rheomorphic, and are often associated with lithic breccias and/or pumice deposits. They record sustained radial pyroclastic density currents fed by low pyroclastic fountains. The onset of ignimbrite emplacement is typically preceded (more rarely followed) by pumice fallout with limited dispersal, and some eruptions lack any associated pumice fall deposit, suggesting the absence of tall eruption columns. Particular attention is given to the correlation of well-developed lithic breccias in the ignimbrites, interpreted as probable tracers of caldera collapses. They record as many as five caldera collapse events, in contrast to the two events reported to date. Inter-ignimbrite periods are characterised by explosive and effusive eruptions with limited dispersal, such as small pumice cones, as well as pedogenesis. These periods have similar characteristics as the current post-Green Tuff activity on the island, and, while not imminent, it is reasonable to postulate the occurrence of another ignimbrite-forming eruption sometime in the future.

Citation

Jordan, N., Rotolo, S., Williams, R., Speranza, F., McIntosh, W., Branney, M. J., & Scaillet, S. (2018). Explosive eruptive history of Pantelleria, Italy : repeated caldera collapse and ignimbrite emplacement at a peralkaline volcano. Journal of Volcanology and Geothermal Research, 349, 47-73. https://doi.org/10.1016/j.jvolgeores.2017.09.013

• Acceptance Date: Sep 17, 2017
• Online Publication Date: Oct 13, 2017
• Publication Date: 2018-01
• Deposit Date: Oct 12, 2017
• Publicly Available Date: Oct 16, 2018
• Journal: Journal of volcanology and geothermal research
• Print ISSN: 0377-0273
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 349
• Pages: 47-73
• DOI: https://doi.org/10.1016/j.jvolgeores.2017.09.013
• Keywords: Peralkaline volcanism; Pantelleria; Ignimbrites; Caldera collapse; Eruptive history; ⁴⁰Ar/³⁹Ar dating
• Public URL: https://hull-repository.worktribe.com/output/455608
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0377027317300781
• Additional Information: This is the accepted manuscript of an article published in Journal of volcanology and geothermal research, 2018. The version of record is available at the DOI link in this record.
• Contract Date: Oct 12, 2017