Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions
Autor(a) principal: | |
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Data de Publicação: | 2010 |
Outros Autores: | , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/20068 https://doi.org/10.1016/j.marmicro.2010.02.002 |
Resumo: | Quantitative analysis of Early Jurassic calcareous nannofossil assemblages from the Peniche section in Portugal have been performed in order to interpret palaeoenvironmental changes occurring in the Lusitanian Basin during the Late Pliensbachian Davoei, Margaritatus and Spinatum Ammonite Zones. Nannofossil data are compared to already published carbon and oxygen stable isotope data, organic matter content (wt.%Total Organic Carbon, TOC), and biomarker analysis. A signi!cant change in calcareous nannofossil assemblages and species diversity at the transition between the Margaritatus and Spinatum Ammonite Zones matches with the pattern shown by geochemical data. This suggests that a profound change in environmental conditions occurred at that time. In the Davoei and Margaritatus Ammonite Zones, in a context of general sea-level rise, the Lusitanian Basin was characterized by water column strati!cation that favoured the sedimentation and preservation of organic matter. Biomarkers and oxygen isotope trends suggest that strati!cation of water masses occurred because of low salinity in surface waters. The shallowest part of the water column, characterized by oligotrophic conditions, was inhabited by the (probable) calcareous dinocyst Schizosphaerella spp., while the deep-dweller Crepidolithus crassus "ourished in the lower photic-zone layers. In the Spinatum Ammonite Zone, a regressive trend occurred and a salinity increase is inferred on the basis of oxygen isotope values. Water masses were probably less strati!ed at that time. The upper photic-zone nannofossil assemblages were still dominated by Schizosphaerella spp. whilst, in the deep photic-zone, Mitrolithus jansae (a Mediterranean taxon) replaced C. crassus (a taxon with NW-European af!nity). This pattern may indicate a change in palaeoceanographic conditions related to surface current circulation. The sea-level fall occurring during the Spinatum Ammonite Zone may have resulted in the partial isolation of the Lusitanian Basin from the NW-Europe basins because of the creation of a threshold. Alternatively, tectonic drowning of North African carbonate platforms in the Late Pliensbachian may have promoted better exchanges of nannoplankton between the Lusitanian Basin and the Mediterranean Tethys via the creation of new seaway connections. |
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Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructionsEarly JurassicPliensbachianCalcareous nannofossilsPalaeoenvironmentLusitanian BasinPortugalQuantitative analysis of Early Jurassic calcareous nannofossil assemblages from the Peniche section in Portugal have been performed in order to interpret palaeoenvironmental changes occurring in the Lusitanian Basin during the Late Pliensbachian Davoei, Margaritatus and Spinatum Ammonite Zones. Nannofossil data are compared to already published carbon and oxygen stable isotope data, organic matter content (wt.%Total Organic Carbon, TOC), and biomarker analysis. A signi!cant change in calcareous nannofossil assemblages and species diversity at the transition between the Margaritatus and Spinatum Ammonite Zones matches with the pattern shown by geochemical data. This suggests that a profound change in environmental conditions occurred at that time. In the Davoei and Margaritatus Ammonite Zones, in a context of general sea-level rise, the Lusitanian Basin was characterized by water column strati!cation that favoured the sedimentation and preservation of organic matter. Biomarkers and oxygen isotope trends suggest that strati!cation of water masses occurred because of low salinity in surface waters. The shallowest part of the water column, characterized by oligotrophic conditions, was inhabited by the (probable) calcareous dinocyst Schizosphaerella spp., while the deep-dweller Crepidolithus crassus "ourished in the lower photic-zone layers. In the Spinatum Ammonite Zone, a regressive trend occurred and a salinity increase is inferred on the basis of oxygen isotope values. Water masses were probably less strati!ed at that time. The upper photic-zone nannofossil assemblages were still dominated by Schizosphaerella spp. whilst, in the deep photic-zone, Mitrolithus jansae (a Mediterranean taxon) replaced C. crassus (a taxon with NW-European af!nity). This pattern may indicate a change in palaeoceanographic conditions related to surface current circulation. The sea-level fall occurring during the Spinatum Ammonite Zone may have resulted in the partial isolation of the Lusitanian Basin from the NW-Europe basins because of the creation of a threshold. Alternatively, tectonic drowning of North African carbonate platforms in the Late Pliensbachian may have promoted better exchanges of nannoplankton between the Lusitanian Basin and the Mediterranean Tethys via the creation of new seaway connections.2010info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/20068http://hdl.handle.net/10316/20068https://doi.org/10.1016/j.marmicro.2010.02.002engREGGIANI, L. [et al.] - Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions. "Marine Micropaleontology". ISSN 0377-8398. 75:1-4 (2010) 1-160377-8398Reggiani, L.Mattioli, E.Pittet, B.Duarte, L. V.Oliveira, L. C. Veiga deComas-Rengifo, M. J.info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2021-05-25T08:22:50Zoai:estudogeral.uc.pt:10316/20068Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:55:11.905344Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
title |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
spellingShingle |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions Reggiani, L. Early Jurassic Pliensbachian Calcareous nannofossils Palaeoenvironment Lusitanian Basin Portugal |
title_short |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
title_full |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
title_fullStr |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
title_full_unstemmed |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
title_sort |
Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions |
author |
Reggiani, L. |
author_facet |
Reggiani, L. Mattioli, E. Pittet, B. Duarte, L. V. Oliveira, L. C. Veiga de Comas-Rengifo, M. J. |
author_role |
author |
author2 |
Mattioli, E. Pittet, B. Duarte, L. V. Oliveira, L. C. Veiga de Comas-Rengifo, M. J. |
author2_role |
author author author author author |
dc.contributor.author.fl_str_mv |
Reggiani, L. Mattioli, E. Pittet, B. Duarte, L. V. Oliveira, L. C. Veiga de Comas-Rengifo, M. J. |
dc.subject.por.fl_str_mv |
Early Jurassic Pliensbachian Calcareous nannofossils Palaeoenvironment Lusitanian Basin Portugal |
topic |
Early Jurassic Pliensbachian Calcareous nannofossils Palaeoenvironment Lusitanian Basin Portugal |
description |
Quantitative analysis of Early Jurassic calcareous nannofossil assemblages from the Peniche section in Portugal have been performed in order to interpret palaeoenvironmental changes occurring in the Lusitanian Basin during the Late Pliensbachian Davoei, Margaritatus and Spinatum Ammonite Zones. Nannofossil data are compared to already published carbon and oxygen stable isotope data, organic matter content (wt.%Total Organic Carbon, TOC), and biomarker analysis. A signi!cant change in calcareous nannofossil assemblages and species diversity at the transition between the Margaritatus and Spinatum Ammonite Zones matches with the pattern shown by geochemical data. This suggests that a profound change in environmental conditions occurred at that time. In the Davoei and Margaritatus Ammonite Zones, in a context of general sea-level rise, the Lusitanian Basin was characterized by water column strati!cation that favoured the sedimentation and preservation of organic matter. Biomarkers and oxygen isotope trends suggest that strati!cation of water masses occurred because of low salinity in surface waters. The shallowest part of the water column, characterized by oligotrophic conditions, was inhabited by the (probable) calcareous dinocyst Schizosphaerella spp., while the deep-dweller Crepidolithus crassus "ourished in the lower photic-zone layers. In the Spinatum Ammonite Zone, a regressive trend occurred and a salinity increase is inferred on the basis of oxygen isotope values. Water masses were probably less strati!ed at that time. The upper photic-zone nannofossil assemblages were still dominated by Schizosphaerella spp. whilst, in the deep photic-zone, Mitrolithus jansae (a Mediterranean taxon) replaced C. crassus (a taxon with NW-European af!nity). This pattern may indicate a change in palaeoceanographic conditions related to surface current circulation. The sea-level fall occurring during the Spinatum Ammonite Zone may have resulted in the partial isolation of the Lusitanian Basin from the NW-Europe basins because of the creation of a threshold. Alternatively, tectonic drowning of North African carbonate platforms in the Late Pliensbachian may have promoted better exchanges of nannoplankton between the Lusitanian Basin and the Mediterranean Tethys via the creation of new seaway connections. |
publishDate |
2010 |
dc.date.none.fl_str_mv |
2010 |
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://hdl.handle.net/10316/20068 http://hdl.handle.net/10316/20068 https://doi.org/10.1016/j.marmicro.2010.02.002 |
url |
http://hdl.handle.net/10316/20068 https://doi.org/10.1016/j.marmicro.2010.02.002 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
REGGIANI, L. [et al.] - Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions. "Marine Micropaleontology". ISSN 0377-8398. 75:1-4 (2010) 1-16 0377-8398 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
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openAccess |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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