Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1016/j.jvolgeores.2017.11.010 http://hdl.handle.net/11449/170391 |
Resumo: | The Cretaceous trachydacites and dacites of Chapecó type (ATC) and dacites and rhyolites of Palmas type (ATP) make up 2.5% of the ~ 800.000 km3 of volcanic pile in the Paraná Magmatic Province (PMP), emplaced at the onset of Gondwana breakup. Together they cover extensive areas in southern Brazil, overlapping volcanic sequences of tholeiitic basalts and andesites; occasional mafic units are also found within the silicic sequence. In the central region of the PMP silicic volcanism comprises porphyritic ATC-type, trachydacite high-grade ignimbrites (strongly welded) overlying aphyric ATP-type, rhyolite high- to extremely high-grade ignimbrites (strongly welded to lava-like). In the southwestern region strongly welded to lava-like high-grade ignimbrites overlie ATP lava domes, while in the southeast lava domes are found intercalated within the ignimbrite sequence. Characteristics of these ignimbrites are: widespread sheet-like deposits (tens to hundreds of km across); absence of basal breccias and basal fallout layers; ubiquitous horizontal to sub-horizontal sheet jointing; massive, structureless to horizontally banded-laminated rock bodies locally presenting flow folding; thoroughly homogeneous vitrophyres or with flow banding-lamination; phenocryst abundance presenting upward and lateral decrease; welded glass blobs in an ‘eutaxitic’-like texture; negligible phenocryst breakage; vitroclastic texture locally preserved; scarcity of lithic fragments. These features, combined with high eruption temperatures (≥ 1000 °C), low water content (≤ 2%) and low viscosities (104–7 Pa s) suggest that the eruptions were characterized by low fountaining, little heat loss during collapse, and high mass fluxes producing extensive deposits. |
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Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern BrazilHigh-grade ignimbritesLow explosivity eruptionsParaná Magmatic ProvinceSilicic volcanismThe Cretaceous trachydacites and dacites of Chapecó type (ATC) and dacites and rhyolites of Palmas type (ATP) make up 2.5% of the ~ 800.000 km3 of volcanic pile in the Paraná Magmatic Province (PMP), emplaced at the onset of Gondwana breakup. Together they cover extensive areas in southern Brazil, overlapping volcanic sequences of tholeiitic basalts and andesites; occasional mafic units are also found within the silicic sequence. In the central region of the PMP silicic volcanism comprises porphyritic ATC-type, trachydacite high-grade ignimbrites (strongly welded) overlying aphyric ATP-type, rhyolite high- to extremely high-grade ignimbrites (strongly welded to lava-like). In the southwestern region strongly welded to lava-like high-grade ignimbrites overlie ATP lava domes, while in the southeast lava domes are found intercalated within the ignimbrite sequence. Characteristics of these ignimbrites are: widespread sheet-like deposits (tens to hundreds of km across); absence of basal breccias and basal fallout layers; ubiquitous horizontal to sub-horizontal sheet jointing; massive, structureless to horizontally banded-laminated rock bodies locally presenting flow folding; thoroughly homogeneous vitrophyres or with flow banding-lamination; phenocryst abundance presenting upward and lateral decrease; welded glass blobs in an ‘eutaxitic’-like texture; negligible phenocryst breakage; vitroclastic texture locally preserved; scarcity of lithic fragments. These features, combined with high eruption temperatures (≥ 1000 °C), low water content (≤ 2%) and low viscosities (104–7 Pa s) suggest that the eruptions were characterized by low fountaining, little heat loss during collapse, and high mass fluxes producing extensive deposits.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista (UNESP)Faculdade de Ciências and Instituto Dom Luiz Universidade de LisboaInstituto de Geociências e Ciências Exatas Universidade Estadual Paulista (UNESP)CAPES: PDSE-2998/13-0CNPq: 484657/2011-9Universidade Estadual Paulista (Unesp)Universidade de LisboaLuchetti, Ana Carolina F. [UNESP]Nardy, Antonio J.R. [UNESP]Madeira, José2018-12-11T16:50:36Z2018-12-11T16:50:36Z2018-04-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article270-286application/pdfhttp://dx.doi.org/10.1016/j.jvolgeores.2017.11.010Journal of Volcanology and Geothermal Research, v. 355, p. 270-286.0377-0273http://hdl.handle.net/11449/17039110.1016/j.jvolgeores.2017.11.0102-s2.0-850344411722-s2.0-85034441172.pdfScopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal of Volcanology and Geothermal Research1,483info:eu-repo/semantics/openAccess2023-10-05T06:05:45Zoai:repositorio.unesp.br:11449/170391Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462023-10-05T06:05:45Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
title |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
spellingShingle |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil Luchetti, Ana Carolina F. [UNESP] High-grade ignimbrites Low explosivity eruptions Paraná Magmatic Province Silicic volcanism |
title_short |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
title_full |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
title_fullStr |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
title_full_unstemmed |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
title_sort |
Silicic, high- to extremely high-grade ignimbrites and associated deposits from the Paraná Magmatic Province, southern Brazil |
author |
Luchetti, Ana Carolina F. [UNESP] |
author_facet |
Luchetti, Ana Carolina F. [UNESP] Nardy, Antonio J.R. [UNESP] Madeira, José |
author_role |
author |
author2 |
Nardy, Antonio J.R. [UNESP] Madeira, José |
author2_role |
author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) Universidade de Lisboa |
dc.contributor.author.fl_str_mv |
Luchetti, Ana Carolina F. [UNESP] Nardy, Antonio J.R. [UNESP] Madeira, José |
dc.subject.por.fl_str_mv |
High-grade ignimbrites Low explosivity eruptions Paraná Magmatic Province Silicic volcanism |
topic |
High-grade ignimbrites Low explosivity eruptions Paraná Magmatic Province Silicic volcanism |
description |
The Cretaceous trachydacites and dacites of Chapecó type (ATC) and dacites and rhyolites of Palmas type (ATP) make up 2.5% of the ~ 800.000 km3 of volcanic pile in the Paraná Magmatic Province (PMP), emplaced at the onset of Gondwana breakup. Together they cover extensive areas in southern Brazil, overlapping volcanic sequences of tholeiitic basalts and andesites; occasional mafic units are also found within the silicic sequence. In the central region of the PMP silicic volcanism comprises porphyritic ATC-type, trachydacite high-grade ignimbrites (strongly welded) overlying aphyric ATP-type, rhyolite high- to extremely high-grade ignimbrites (strongly welded to lava-like). In the southwestern region strongly welded to lava-like high-grade ignimbrites overlie ATP lava domes, while in the southeast lava domes are found intercalated within the ignimbrite sequence. Characteristics of these ignimbrites are: widespread sheet-like deposits (tens to hundreds of km across); absence of basal breccias and basal fallout layers; ubiquitous horizontal to sub-horizontal sheet jointing; massive, structureless to horizontally banded-laminated rock bodies locally presenting flow folding; thoroughly homogeneous vitrophyres or with flow banding-lamination; phenocryst abundance presenting upward and lateral decrease; welded glass blobs in an ‘eutaxitic’-like texture; negligible phenocryst breakage; vitroclastic texture locally preserved; scarcity of lithic fragments. These features, combined with high eruption temperatures (≥ 1000 °C), low water content (≤ 2%) and low viscosities (104–7 Pa s) suggest that the eruptions were characterized by low fountaining, little heat loss during collapse, and high mass fluxes producing extensive deposits. |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-12-11T16:50:36Z 2018-12-11T16:50:36Z 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.2017.11.010 Journal of Volcanology and Geothermal Research, v. 355, p. 270-286. 0377-0273 http://hdl.handle.net/11449/170391 10.1016/j.jvolgeores.2017.11.010 2-s2.0-85034441172 2-s2.0-85034441172.pdf |
url |
http://dx.doi.org/10.1016/j.jvolgeores.2017.11.010 http://hdl.handle.net/11449/170391 |
identifier_str_mv |
Journal of Volcanology and Geothermal Research, v. 355, p. 270-286. 0377-0273 10.1016/j.jvolgeores.2017.11.010 2-s2.0-85034441172 2-s2.0-85034441172.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 |
270-286 application/pdf |
dc.source.none.fl_str_mv |
Scopus 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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1797789298539364352 |