Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal

The Armorican Quartzite is one of the most characteristic units of the Paleozoic of SW Europe, being represented in the Lower Ordovician succession of Brittany and Normandy (western France), and also over most of the Hesperian and Iberian massifs of the Iberian Peninsula (in the clarified sense of S...

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Autores: Sá, Artur A., Gutiérrez-Marco, J. C., Piçarra, José Manuel, García-Bellido, Diego, Vaz, N., Aceñolaza, Guillermo F.
Tipo de recurso: otro
Fecha de publicación:2011
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/61070
Acceso en línea:http://hdl.handle.net/10261/61070
Access Level:acceso abierto
Palabra clave:Iberian Peninsula
Ordovician
Armorican quartzite facies
Cruziana stratigraphy
Regional Geology
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spelling Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central PortugalSá, Artur A.Gutiérrez-Marco, J. C.Piçarra, José ManuelGarcía-Bellido, DiegoVaz, N.Aceñolaza, Guillermo F.Iberian PeninsulaOrdovicianArmorican quartzite faciesCruziana stratigraphyRegional GeologyThe Armorican Quartzite is one of the most characteristic units of the Paleozoic of SW Europe, being represented in the Lower Ordovician succession of Brittany and Normandy (western France), and also over most of the Hesperian and Iberian massifs of the Iberian Peninsula (in the clarified sense of San José, 2006), with the exception of the Ossa-Morena and South-Portuguese zones (Gutiérrez-Marco et al., 2002; Vera, 2004; Ribeiro, 2006). In Portugal and from north to south, the Armorican Quartzite facies is equivalent to the Marão Formation of Trás-os-Montes (Sá et al., 2005), the Santa Justa Formation of the Tabagón-Valongo-Tamames domain (Romano and Diggens, 1974), the Armorican Quartzite Formation of the Buçaco and Amêndoa-Mação areas (Young, 1988; Romão, 2000a) and the Serra do Brejo Formation in the Dornes area (Cooper, 1980). In spite of the generalized absence of biostratigraphical ties for correlation other than ichnofossils and a few chitinozoan or graptolite data, the latter generally coming from the overlying shales, the Armorican Quartzite in Portugal have been considered as involving a diachronism in sedimentation from Arenig to Llandeilo, becoming younger from west to east (Ribeiro, 1974) according to regional data from the Valongo to Trás-os-Montes areas. These data have been compiled in some syntheses (Hammann et al., 1982; Romano, 1982; Oliveira et al., 1992). However, the single paleontological argument in support of such diachronism, a Llandeilian trilobite found in the middle part of the Marão Formation at Moncorvo (Teixeira and Rebelo, 1976) was later reviewed by Gutiérrez- Marco et al. (1995), and Sá et al. (2003, 2009), who demonstrated that the supposed trilobite was in reality the trace fossil Rusophycus carleyi (James), also recorded in other Gondwanan areas within the Arenigian succession (Seilacher, 1970; Gibb et al., 2010). No other authors were able to demonstrate the claimed diachronism in the sedimentation of the Armorican Quartzite, whose deposit took place entirely in the Eremochitina brevis chitinozoan biozone (Paris, 1981, 1990; Paris et al., 1982, 2007), regarded as “early-mid Arenigian” or as late Floian according to the global scale (Paris et al., 2007; Videt et al., 2010). Romão et al. (2010) recently questioned the current age of the Armorican Quartzite in the southern Central Iberian Zone, and supported a local late Cambrian age for this formation in the Amêndoa- Carvoeiro synform based in a couple of ichnological data, a single U-Pb dating, and some highly speculative tectonostratigraphic inferences which in our opinion are far from being demonstrated. Also with reference to this area, Romão et al. (2010) envisaged the Armorican Quartzite as a highly diachronic late Cambrian to Early Ordovician unit for the Iberian Peninsula. This statement is refuted here with the presentation of new ichnologic evidence that supports the previous Early Ordovician dating of the Armorican Quartzite in the Amêndoa-Carvoeiro synform.Peer reviewedCSIC - Instituto Geológico y Minero de España (IGME)201220122011info:eu-repo/semantics/otherhttp://purl.org/coar/resource_type/c_3248info:eu-repo/semantics/bookParthttp://hdl.handle.net/10261/61070reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglésinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/610702026-05-22T06:33:51Z
dc.title.none.fl_str_mv Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
title Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
spellingShingle Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
Sá, Artur A.
Iberian Peninsula
Ordovician
Armorican quartzite facies
Cruziana stratigraphy
Regional Geology
title_short Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
title_full Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
title_fullStr Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
title_full_unstemmed Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
title_sort Ordovician vs. “Cambrian” ichnofossils in the Armorican Quartzite of Central Portugal
dc.creator.none.fl_str_mv Sá, Artur A.
Gutiérrez-Marco, J. C.
Piçarra, José Manuel
García-Bellido, Diego
Vaz, N.
Aceñolaza, Guillermo F.
author Sá, Artur A.
author_facet Sá, Artur A.
Gutiérrez-Marco, J. C.
Piçarra, José Manuel
García-Bellido, Diego
Vaz, N.
Aceñolaza, Guillermo F.
author_role author
author2 Gutiérrez-Marco, J. C.
Piçarra, José Manuel
García-Bellido, Diego
Vaz, N.
Aceñolaza, Guillermo F.
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Iberian Peninsula
Ordovician
Armorican quartzite facies
Cruziana stratigraphy
Regional Geology
topic Iberian Peninsula
Ordovician
Armorican quartzite facies
Cruziana stratigraphy
Regional Geology
description The Armorican Quartzite is one of the most characteristic units of the Paleozoic of SW Europe, being represented in the Lower Ordovician succession of Brittany and Normandy (western France), and also over most of the Hesperian and Iberian massifs of the Iberian Peninsula (in the clarified sense of San José, 2006), with the exception of the Ossa-Morena and South-Portuguese zones (Gutiérrez-Marco et al., 2002; Vera, 2004; Ribeiro, 2006). In Portugal and from north to south, the Armorican Quartzite facies is equivalent to the Marão Formation of Trás-os-Montes (Sá et al., 2005), the Santa Justa Formation of the Tabagón-Valongo-Tamames domain (Romano and Diggens, 1974), the Armorican Quartzite Formation of the Buçaco and Amêndoa-Mação areas (Young, 1988; Romão, 2000a) and the Serra do Brejo Formation in the Dornes area (Cooper, 1980). In spite of the generalized absence of biostratigraphical ties for correlation other than ichnofossils and a few chitinozoan or graptolite data, the latter generally coming from the overlying shales, the Armorican Quartzite in Portugal have been considered as involving a diachronism in sedimentation from Arenig to Llandeilo, becoming younger from west to east (Ribeiro, 1974) according to regional data from the Valongo to Trás-os-Montes areas. These data have been compiled in some syntheses (Hammann et al., 1982; Romano, 1982; Oliveira et al., 1992). However, the single paleontological argument in support of such diachronism, a Llandeilian trilobite found in the middle part of the Marão Formation at Moncorvo (Teixeira and Rebelo, 1976) was later reviewed by Gutiérrez- Marco et al. (1995), and Sá et al. (2003, 2009), who demonstrated that the supposed trilobite was in reality the trace fossil Rusophycus carleyi (James), also recorded in other Gondwanan areas within the Arenigian succession (Seilacher, 1970; Gibb et al., 2010). No other authors were able to demonstrate the claimed diachronism in the sedimentation of the Armorican Quartzite, whose deposit took place entirely in the Eremochitina brevis chitinozoan biozone (Paris, 1981, 1990; Paris et al., 1982, 2007), regarded as “early-mid Arenigian” or as late Floian according to the global scale (Paris et al., 2007; Videt et al., 2010). Romão et al. (2010) recently questioned the current age of the Armorican Quartzite in the southern Central Iberian Zone, and supported a local late Cambrian age for this formation in the Amêndoa- Carvoeiro synform based in a couple of ichnological data, a single U-Pb dating, and some highly speculative tectonostratigraphic inferences which in our opinion are far from being demonstrated. Also with reference to this area, Romão et al. (2010) envisaged the Armorican Quartzite as a highly diachronic late Cambrian to Early Ordovician unit for the Iberian Peninsula. This statement is refuted here with the presentation of new ichnologic evidence that supports the previous Early Ordovician dating of the Armorican Quartzite in the Amêndoa-Carvoeiro synform.
publishDate 2011
dc.date.none.fl_str_mv 2011
2012
2012
dc.type.none.fl_str_mv info:eu-repo/semantics/other
http://purl.org/coar/resource_type/c_3248
dc.type.openaire.fl_str_mv info:eu-repo/semantics/bookPart
format other
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/61070
url http://hdl.handle.net/10261/61070
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv CSIC - Instituto Geológico y Minero de España (IGME)
publisher.none.fl_str_mv CSIC - Instituto Geológico y Minero de España (IGME)
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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