Melt stripping and agglutination of pyroclasts during the explosive eruption of low viscosity magmas

Jones, Thomas J.; Russell, James K.; Brown, Richard J.; Hollendonner, Lea

Abstract

Volcanism on Earth and on other planets and satellites is dominated by the eruption of low viscosity magmas. During explosive eruption, high melt temperatures and the inherent low viscosity of the fluidal pyroclasts allow for substantial post-fragmentation modification during transport obscuring the record of primary, magmatic fragmentation processes. Here, we show these syn-eruption modifications, in the form of melt stripping and agglutination, to be advantageous for providing fundamental insights into lava fountain and jet dynamics, including eruption velocities, grain size distributions and melt physical properties. We show how enigmatic, complex pyroclasts termed pelletal lapilli form by a two-stage process operating above the magmatic fragmentation surface. Melt stripping from pyroclast surfaces creates a spray of fine melt droplets whilst sustained transport in the fountain allows for agglutination and droplet scavenging, thereby coarsening the grain size distribution. We conclude with a set of universal regime diagrams, applicable for all fluidal fountain products, that link fundamental physical processes to eruption conditions and melt physical properties.

Citation

Jones, T. J., Russell, J. K., Brown, R. J., & Hollendonner, L. (2022). Melt stripping and agglutination of pyroclasts during the explosive eruption of low viscosity magmas. Nature Communications, 13(1), https://doi.org/10.1038/s41467-022-28633-w

• Journal Article Type: Article
• Acceptance Date: Feb 2, 2022
• Online Publication Date: Feb 22, 2022
• Publication Date: 2022
• Deposit Date: May 16, 2022
• Publicly Available Date: May 16, 2022
• Journal: Nature Communications
• Electronic ISSN: 2041-1723
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 1
• DOI: https://doi.org/10.1038/s41467-022-28633-w
• Public URL: https://durham-repository.worktribe.com/output/1208443