Please use this identifier to cite or link to this item: http://doi.org/10.25358/openscience-278
Authors: Müller, Sebastian
Helo, Christoph
Keller, Franziska
Taddeucci, J.
Castro, Jonathan
Title: First experimental observations on melting and chemical modification of volcanic ash during lightning interaction
Online publication date: 23-Jan-2019
Language: english
Abstract: Electrification in volcanic ash plumes often leads to syn-eruptive lightning discharges. High temperatures in and around lightning plasma channels have the potential to chemically alter, re-melt, and possibly volatilize ash fragments in the eruption cloud. In this study, we experimentally simulate temperature conditions of volcanic lightning in the laboratory, and systematically investigate the effects of rapid melting on the morphology and chemical composition of ash. Samples of different size and composition are ejected towards an artificially generated electrical arc. Post-experiment ash morphologies include fully melted spheres, partially melted particles, agglomerates, and vesiculated particles. High-speed imaging reveals various processes occurring during the short lightning-ash interactions, such as particle melting and rounding, foaming, and explosive particle fragmentation. Chemical analyses of the flash-melted particles reveal considerable bulk loss of Cl, S, P and Na through thermal vaporization. Element distribution patterns suggest convection as a key process of element transport from the interior of the melt droplet to rim where volatiles are lost. Modeling the degree of sodium loss delivers maximum melt temperatures between 3290 and 3490 K. Our results imply that natural lighting strikes may be an important agent of syn-eruptive morphological and chemical processing of volcanic ash.
DDC: 550 Geowissenschaften
550 Earth sciences
Institution: Johannes Gutenberg-Universität Mainz
Department: FB 09 Chemie, Pharmazie u. Geowissensch.
Place: Mainz
DOI: http://doi.org/10.25358/openscience-278
Version: Published version
Publication type: Zeitschriftenaufsatz
License: CC BY
Information on rights of use: https://creativecommons.org/licenses/by/4.0/
Journal: Scientific reports
8
Pages or article number: Art. 1389
Publisher: Macmillan Publishers Limited, part of Springer Nature
Publisher place: London
Issue date: 2018
ISSN: 2045-2322
Publisher URL: http://dx.doi.org/10.1038/s41598-018-19608-3
Publisher DOI: 10.1038/s41598-018-19608-3
Appears in collections:JGU-Publikationen

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