How to fragment peralkaline rhyolites: Observations on pumice using combined multi-scale 2D and 3D imaging

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dc.identifier.uri http://dx.doi.org/10.15488/1654
dc.identifier.uri http://www.repo.uni-hannover.de/handle/123456789/1679
dc.contributor.author Hughes, Ery C.
dc.contributor.author Neave, David A.
dc.contributor.author Dobson, Katherine J.
dc.contributor.author Withers, Philip J.
dc.contributor.author Edmonds, Marie
dc.date.accessioned 2017-06-21T06:56:18Z
dc.date.available 2017-06-21T06:56:18Z
dc.date.issued 2017
dc.identifier.citation Hughes, E.C.; Neave, D.A.; Dobson, K.J.; Withers, P.J.; Edmonds, M.: How to fragment peralkaline rhyolites: Observations on pumice using combined multi-scale 2D and 3D imaging. In: Journal of Volcanology and Geothermal Research 336 (2017), S. 179-191. DOI: https://doi.org/10.1016/j.jvolgeores.2017.02.020
dc.description.abstract Peralkaline rhyolites are volatile-rich magmas that typically erupt in continental rift settings. The high alkali and halogen content of these magmas results in viscosities two to three orders of magnitude lower than in calc-alkaline rhyolites. Unless extensive microlite crystallisation occurs, the calculated strain rates required for fragmentation are unrealistically high, yet peralkaline pumices from explosive eruptions of varying scales are commonly microlite-free. Here we present a combined 2D scanning electron microscopy and 3D X-ray microtomography study of peralkaline rhyolite vesicle textures designed to investigate fragmentation processes. Microlite-free peralkaline pumice textures from Pantelleria, Italy, strongly resemble those from calc-alkaline rhyolites on both macro and micro scales. These textures imply that the pumices fragmented in a brittle fashion and that their peralkaline chemistry had little direct effect on textural evolution during bubble nucleation and growth. We suggest that the observed pumice textures evolved in response to high decompression rates and that peralkaline rhyolite magmas can fragment when strain localisation and high bubble overpressures develop during rapid ascent. eng
dc.description.sponsorship EPSRC/EP/F007906/1
dc.description.sponsorship EPSRC/EP/I02249X/1
dc.description.sponsorship EVOKES ERC 247076
dc.description.sponsorship NERC NE/M01687/1
dc.description.sponsorship Alexander von Humboldt Foundation
dc.language.iso eng
dc.publisher Amsterdam : Elsevier B.V.
dc.relation.ispartofseries Journal of Volcanology and Geothermal Research 336 (2017)
dc.rights CC BY 4.0 Unported
dc.rights.uri https://creativecommons.org/licenses/by/4.0/
dc.subject Fragmentation eng
dc.subject Peralkaline rhyolite eng
dc.subject Textural analysis eng
dc.subject X-ray microtromography eng
dc.subject Alkalinity eng
dc.subject Geologic models eng
dc.subject Scanning electron microscopy eng
dc.subject Strain rate eng
dc.subject Fragmentation eng
dc.subject Fragmentation process eng
dc.subject Peralkaline rhyolites eng
dc.subject Strain localisation eng
dc.subject Textural analysis eng
dc.subject Textural evolution eng
dc.subject Three orders of magnitude eng
dc.subject Volatile-rich magma eng
dc.subject Granite eng
dc.subject.ddc 550 | Geowissenschaften ger
dc.subject.ddc 551 | Geologie, Hydrologie, Meteorologie ger
dc.title How to fragment peralkaline rhyolites: Observations on pumice using combined multi-scale 2D and 3D imaging
dc.type article
dc.type Text
dc.relation.issn 0377-0273
dc.relation.doi https://doi.org/10.1016/j.jvolgeores.2017.02.020
dc.bibliographicCitation.volume 336
dc.bibliographicCitation.firstPage 179
dc.bibliographicCitation.lastPage 191
dc.description.version publishedVersion
tib.accessRights frei zug�nglich


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