Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil
Main Author: | |
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Publication Date: | 2018 |
Other Authors: | , , |
Format: | Article |
Language: | eng |
Source: | Repositório Institucional da UNESP |
Download full: | http://dx.doi.org/10.1016/j.jvolgeores.2017.04.012 http://hdl.handle.net/11449/160358 |
Summary: | The 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. |
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Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern BrazilParana-Etendeka ProvinceChapeco rocksPalmas rocksSilicic volcanismHigh-grade ignimbritesThe 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.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)NSFUniv Estadual Paulista, Inst Geociencias & Ciencias Exatas, BR-13506900 Rio Claro, SP, BrazilUniv Canterbury, Dept Geol, Christchurch 8041, New ZealandVanderbilt Univ, Earth & Environm Sci, Nashville, TN 37235 USAUniv Estadual Paulista, Inst Geociencias & Ciencias Exatas, BR-13506900 Rio Claro, SP, BrazilCNPq: 484657/2011-9CAPES: PDSE-2998/13-0FAPESP: 11/10508-6NSF: EAR-1151337Elsevier B.V.Universidade Estadual Paulista (Unesp)Univ CanterburyVanderbilt UnivLuchetti, Ana Carolina F. [UNESP]Gravley, Darren M.Gualda, Guilherme A. R.Nardy, Antonio J. R. [UNESP]2018-11-26T16:03:02Z2018-11-26T16:03:02Z2018-04-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article87-97application/pdfhttp://dx.doi.org/10.1016/j.jvolgeores.2017.04.012Journal Of Volcanology And Geothermal Research. Amsterdam: Elsevier Science Bv, v. 355, p. 87-97, 2018.0377-0273http://hdl.handle.net/11449/16035810.1016/j.jvolgeores.2017.04.012WOS:000435057900008WOS000435057900008.pdfWeb of Sciencereponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal Of Volcanology And Geothermal Research1,483info:eu-repo/semantics/openAccess2023-12-28T06:21:26Zoai:repositorio.unesp.br:11449/160358Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462023-12-28T06:21:26Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
title |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
spellingShingle |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil Luchetti, Ana Carolina F. [UNESP] Parana-Etendeka Province Chapeco rocks Palmas rocks Silicic volcanism High-grade ignimbrites |
title_short |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
title_full |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
title_fullStr |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
title_full_unstemmed |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
title_sort |
Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Parana Magmatic Province, southern Brazil |
author |
Luchetti, Ana Carolina F. [UNESP] |
author_facet |
Luchetti, Ana Carolina F. [UNESP] Gravley, Darren M. Gualda, Guilherme A. R. Nardy, Antonio J. R. [UNESP] |
author_role |
author |
author2 |
Gravley, Darren M. Gualda, Guilherme A. R. Nardy, Antonio J. R. [UNESP] |
author2_role |
author author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) Univ Canterbury Vanderbilt Univ |
dc.contributor.author.fl_str_mv |
Luchetti, Ana Carolina F. [UNESP] Gravley, Darren M. Gualda, Guilherme A. R. Nardy, Antonio J. R. [UNESP] |
dc.subject.por.fl_str_mv |
Parana-Etendeka Province Chapeco rocks Palmas rocks Silicic volcanism High-grade ignimbrites |
topic |
Parana-Etendeka Province Chapeco rocks Palmas rocks Silicic volcanism High-grade ignimbrites |
description |
The 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. |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-11-26T16:03:02Z 2018-11-26T16:03:02Z 2018-04-15 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1016/j.jvolgeores.2017.04.012 Journal Of Volcanology And Geothermal Research. Amsterdam: Elsevier Science Bv, v. 355, p. 87-97, 2018. 0377-0273 http://hdl.handle.net/11449/160358 10.1016/j.jvolgeores.2017.04.012 WOS:000435057900008 WOS000435057900008.pdf |
url |
http://dx.doi.org/10.1016/j.jvolgeores.2017.04.012 http://hdl.handle.net/11449/160358 |
identifier_str_mv |
Journal Of Volcanology And Geothermal Research. Amsterdam: Elsevier Science Bv, v. 355, p. 87-97, 2018. 0377-0273 10.1016/j.jvolgeores.2017.04.012 WOS:000435057900008 WOS000435057900008.pdf |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Journal Of Volcanology And Geothermal Research 1,483 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
87-97 application/pdf |
dc.publisher.none.fl_str_mv |
Elsevier B.V. |
publisher.none.fl_str_mv |
Elsevier B.V. |
dc.source.none.fl_str_mv |
Web of Science reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
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