Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil

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dc.contributor.authorLuchetti, Ana Carolina F. [UNESP]
dc.contributor.authorGravley, Darren M.
dc.contributor.authorGualda, Guilherme A. R.
dc.contributor.authorNardy, Antonio J. R. [UNESP]
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniv Canterbury
dc.contributor.institutionVanderbilt Univ
dc.date.accessioned2018-11-26T16:03:02Z
dc.date.available2018-11-26T16:03:02Z
dc.date.issued2018-04-15
dc.description.abstractThe Parana-Etendeka Province is a Lower Cretaceous huge bimodal tholeiitic volcanic province (1 million.km(3)) that predated the Gondwana breakup. Its silicic portion makes up a total volume of at least 20,000 km(3) and in southern Brazil it comprises the Chapeco porphyritic high-Ti trachydacites-dacites and the Palmas microporphyritic-aphyric low-Ti dacites-rhyolites. The widespread silicic sheets are debated in the literature because they bear similarities between lavas and high grade ignimbrites. Here we provide new observations and interpretations for flow units with large, dark, and vesicle-poor lens-shaped blobs surrounded by a light-colored matrix. The textural features (macro- to micro-scale) of these blobs are different from typical pumice and/or fiamme and support a low explosivity pyroclastic origin, possibly low-column fountain eruptions with discharge rates high enough to produce laterally extensive high-grade ignimbrites. Such an interpretation, combined with a conspicuous absence of lithic fragments in the deposits, is aligned with a lack of identified calderas in the Parana-Etendeka Province. Maximum timescales of crystallization associated with the juvenile blobs and estimated from CSD slopes are on the order of millennia for phenocryst populations and on the order of decades for microphenocryst populations. (C) 2017 Elsevier B.V. All rights reserved.en
dc.description.affiliationUniv Estadual Paulista, Inst Geociencias & Ciencias Exatas, BR-13506900 Rio Claro, SP, Brazil
dc.description.affiliationUniv Canterbury, Dept Geol, Christchurch 8041, New Zealand
dc.description.affiliationVanderbilt Univ, Earth & Environm Sci, Nashville, TN 37235 USA
dc.description.affiliationUnespUniv Estadual Paulista, Inst Geociencias & Ciencias Exatas, BR-13506900 Rio Claro, SP, Brazil
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipNSF
dc.description.sponsorshipIdCNPq: 484657/2011-9
dc.description.sponsorshipIdCAPES: PDSE-2998/13-0
dc.description.sponsorshipIdFAPESP: 11/10508-6
dc.description.sponsorshipIdNSF: EAR-1151337
dc.format.extent87-97
dc.identifierhttp://dx.doi.org/10.1016/j.jvolgeores.2017.04.012
dc.identifier.citationJournal Of Volcanology And Geothermal Research. Amsterdam: Elsevier Science Bv, v. 355, p. 87-97, 2018.
dc.identifier.doi10.1016/j.jvolgeores.2017.04.012
dc.identifier.fileWOS000435057900008.pdf
dc.identifier.issn0377-0273
dc.identifier.urihttp://hdl.handle.net/11449/160358
dc.identifier.wosWOS:000435057900008
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofJournal Of Volcanology And Geothermal Research
dc.relation.ispartofsjr1,483
dc.rights.accessRightsAcesso aberto
dc.sourceWeb of Science
dc.subjectParana-Etendeka Province
dc.subjectChapeco rocks
dc.subjectPalmas rocks
dc.subjectSilicic volcanism
dc.subjectHigh-grade ignimbrites
dc.titleTextural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazilen
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderElsevier B.V.

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