Opin vísindi

Measuring the degree of “nanotilization” of volcanic glasses: Understanding syn-eruptive processes recorded in melt inclusions

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dc.contributor Háskóli Íslands
dc.contributor University of Iceland
dc.contributor.author Di Genova, Danilo
dc.contributor.author Caracciolo, Alberto
dc.contributor.author Kolzenburg, Stephan
dc.date.accessioned 2019-10-02T13:11:04Z
dc.date.available 2019-10-02T13:11:04Z
dc.date.issued 2018-10
dc.identifier.citation Di Genova, D., Caracciolo, A., & Kolzenburg, S. (2018). Measuring the degree of “nanotilization” of volcanic glasses: Understanding syn-eruptive processes recorded in melt inclusions. Lithos, 318-319, 209-218. doi:https://doi.org/10.1016/j.lithos.2018.08.011
dc.identifier.issn 0024-4937
dc.identifier.uri https://hdl.handle.net/20.500.11815/1282
dc.description Publisher's version (útgefin grein)
dc.description.abstract Iron and water content substantially affect the physical properties of natural silicate melts and may, therefore, influence magmatic and volcanic processes such as crystallization, degassing, flow behaviour and eruptive style. Here we present Raman spectroscopic data for a set of synthetic and natural multicomponent glasses with varying iron oxidation state and water content. We systematically study the effect of different Raman excitation sources on the spectral response of both crystal free and magnetite nanolite bearing glasses spanning basaltic to calc- and per-alkaline rhyolitic compositions. Based on these data we document changes in Raman spectra resulting from the formation of nano-scale crystals. We show that the peak located at ~970 cm−1 is directly related to the presence of Fe2O3 dissolved in the quenched melt structure and that this feature is present regardless of the chemical composition of the sample and the Raman excitation source. We further show that a peak between 670 and 690 cm−1, which is not related to any other spectral feature of the glass structure, reveals the presence of nanolites. Based on systematic spectral investigations of this feature, we present a new index that allows to identify if iron is present in the nanocrystalline state and/or bound in the glass structure. Since the melt structural and physical effects of the formation of nanolites can heavily affect the flow behaviour of melts and the eruptive style of volcanoes, the results presented in this study significantly broaden the application of Raman spectroscopy for investigations of nano-heterogeneity in synthetic and natural glasses. We apply this method to study both the degree of nanolitization as well as the H2O content and iron oxidation state of groundmass glasses as well as melt inclusions and glass embayments in explosive products from Pantelleria island (Italy). We observe that the process of nanotilization is not purely restricted to magnetite nanolites but that Raman spectroscopy may also identify the incipient crystalization of pyroxene and feldspar at sub-micron scale. The data document that nanolite formation correlates well with the observed intensity of the respective eruptions suggesting that structural changes in the melt, caused by incipient crystallization play an important role in defining the eruptive style of relatively low viscosity magmas.
dc.description.sponsorship D. Di Genova was supported by the NSFGEO-NERC “Quantifying disequilibrium processes in basaltic volcanism” (reference: NE/N018567/1). A. Caracciolo was supported by the Erasmus+ traineeship program from Pisa University (Italy). S. Kolzenburg acknowledges funding from H2020 MSCA grant “DYNAVOLC” (#795044).
dc.format.extent 209-218
dc.language.iso en
dc.publisher Elsevier BV
dc.relation info:eu-repo/grantAgreement/EC/H2020/795044
dc.relation.ispartofseries Lithos;318-319
dc.rights info:eu-repo/semantics/openAccess
dc.subject Glass
dc.subject Iron
dc.subject Nanoscale
dc.subject Raman spectroscopy
dc.subject Melt inclusion
dc.subject Volcanic eruption
dc.subject Málmar
dc.subject Járn
dc.subject Litrófsgreining
dc.subject Eldgos
dc.title Measuring the degree of “nanotilization” of volcanic glasses: Understanding syn-eruptive processes recorded in melt inclusions
dc.type info:eu-repo/semantics/article
dcterms.license This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Contents lists available atScienceDirectLithosjournal homepage:www.elsevier.com/locate/lithos
dc.description.version Peer Reviewed
dc.identifier.journal Lithos
dc.identifier.doi 10.1016/j.lithos.2018.08.011
dc.contributor.department Jarðvísindastofnun (HÍ)
dc.contributor.department Institute of Earth Sciences (UI)
dc.contributor.school Verkfræði- og náttúruvísindasvið (HÍ)
dc.contributor.school School of Engineering and Natural Sciences (UI)

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