biostudies-literatureClarke BRCUK | Natural Environment Research CouncilMedical Research CouncilRCUK | Natural Environment Research Council (NERC)Natural Environment Research Council2010https://www.ebi.ac.uk/biostudies/studies/S-EPMC6494994biostudies-literatureUnknown10(1)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 characterNature communicationsFluidal pyroclasts reveal the intensity of peralkaline rhyolite pumice cone eruptions.PMC6494994NE/L013932/1smru10001NE/L002558/11645430MR/S033505/1Dessalegn FCortes JAClarke BFontijn KYirgu GButler IHutchison WNaylor MCalder ESfalseFluidal pyroclasts reveal the intensity of peralkaline rhyolite pumice cone eruptions.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 character2019-01-01T00:00:00Z2019 May2025-05-18T12:50:49.162Z2025-05-18T12:50:49.162ZS-EPMC64949943104361610.1038/s41467-019-09947-8