Fluidal pyroclasts reveal the intensity of peralkaline rhyolite pumice cone eruptions

Benjamin Clarke, Eliza Calder, Firawalin Dessalegn, Karen Fontijn, Joaquin Alberto Cortes, Mark Naylor, Ian Butler, William Hutchison, Gezahegn Yirgu

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Peralkaline rhyolites are medium to low viscosity, volatile-rich magmas typically associated with rift zones and extensional settings. The dynamics of peralkaline rhyolite eruptions remain elusive with no direct observations recorded, significantly hindering the assessment of hazard and risk. Here we describe uniquely-preserved, fluidal-shaped pyroclasts found within pumice cone deposits at Aluto, a peralkaline rhyolite caldera in the Main Ethiopian Rift. We use a combination of field-observations, geochemistry, X-ray computed microtomography (XCT) and thermal-modelling to investigate how these pyroclasts are formed. We find that they deform during flight and, depending on size, quench prior to deposition or continue to inflate then quench in-situ. These findings reveal important characteristics of the eruptions that gave rise to them: that despite the relatively low viscosity of these magmas, and similarities to basaltic scoria-cone deposits, moderate to intense, unstable, eruption columns are developed; meaning that such eruptions can generate extensive tephra-fall and pyroclastic density currents.
Original languageEnglish
Article number2010
JournalNature Communications
Publication statusPublished - 1 May 2019


Dive into the research topics of 'Fluidal pyroclasts reveal the intensity of peralkaline rhyolite pumice cone eruptions'. Together they form a unique fingerprint.

Cite this