Refletions on the Recôncavo Series, Brazil
Chronostratigraphic units are of prime importance in geology. Their limits provide the basis for reliable chrono-correlations, both locally and globally. Of the several criteria used nowadays for the definition and characterization of chronostratigraphic units, fossil events are particularly impor...
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| Format: | Article |
| Language: | English |
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Universidade Federal do Rio de Janeiro
2018-08-01
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| Series: | Anuário do Instituto de Geociências |
| Subjects: | |
| Online Access: | http://www.anuario.igeo.ufrj.br/2018_2/2018_2_276_296.pdf |
| _version_ | 1797967952192995328 |
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| author | Rogério Loureiro Antunes Ricardo Latgé Milvard de Azevedo Janaína Teixeira Lobo |
| author_facet | Rogério Loureiro Antunes Ricardo Latgé Milvard de Azevedo Janaína Teixeira Lobo |
| author_sort | Rogério Loureiro Antunes |
| collection | DOAJ |
| description | Chronostratigraphic units are of prime importance in geology. Their limits provide the basis for reliable chrono-correlations,
both locally and globally. Of the several criteria used nowadays for the definition and characterization of chronostratigraphic units,
fossil events are particularly important. This article presents a brief review of chronostratigraphic units and their applicability, with
special emphasis on the Recôncavo Series and the current correlation of its stages with those of the Upper Jurassic-Lower Cretaceous. Some lines of research are suggested, including Rb/Sr radiometric datings by the total rock method. Limited evidence based
on the latter challenges the classic correlation of the Recôncavo Series with the Upper Jurassic-Lower Cretaceous. This is the case of
the Dom João and the base of Rio da Serra stages, dated radiometrically as Triassic. Lastly, it is suggested that the base of the Albian
Stage (i.e, the top of Alagoas Stage) coincides with the base of a distinctive, thick salt layer (Ibura Event) which is widely represented
in basins Santos through Sergipe-Alagoas. This interpretation contrasts with the new tendency noted in some recent Brazilian papers, which place the Aptian-Albian boundary within post-evaporite marine (carbonatic shelf) sediments of those same basins, on the
basis of microfossils, particularly planktonic foraminifera. This apparent contradiction could simply reflect the diachronous LADs
of some index species. The magnitude of the evaporitic event in the South Atlantic proto-ocean (originated from the Tethys Sea to
the north) could have triggered major paleoenvironmental disturbances in oceanic surface waters over much of the planet. A possible
consequence of such changes was the faunal turnover noted in foraminiferal successions across the Aptian-Albian boundary, in its
type section and elsewhere in the world. |
| first_indexed | 2024-04-11T02:39:22Z |
| format | Article |
| id | doaj.art-cd3bedde3633472f80cc07198b28e54a |
| institution | Directory Open Access Journal |
| issn | 0101-9759 1982-3908 |
| language | English |
| last_indexed | 2024-04-11T02:39:22Z |
| publishDate | 2018-08-01 |
| publisher | Universidade Federal do Rio de Janeiro |
| record_format | Article |
| series | Anuário do Instituto de Geociências |
| spelling | doaj.art-cd3bedde3633472f80cc07198b28e54a2023-01-02T19:35:05ZengUniversidade Federal do Rio de JaneiroAnuário do Instituto de Geociências0101-97591982-39082018-08-01412276296http://dx.doi.org/10.11137/2018_2_276_296Refletions on the Recôncavo Series, BrazilRogério Loureiro Antunes0Ricardo Latgé Milvard de Azevedo1Janaína Teixeira Lobo2Universidade Federal do Rio de JaneiroUniversidade Federal do Rio de JaneiroUniversidade Federal do Rio de JaneiroChronostratigraphic units are of prime importance in geology. Their limits provide the basis for reliable chrono-correlations, both locally and globally. Of the several criteria used nowadays for the definition and characterization of chronostratigraphic units, fossil events are particularly important. This article presents a brief review of chronostratigraphic units and their applicability, with special emphasis on the Recôncavo Series and the current correlation of its stages with those of the Upper Jurassic-Lower Cretaceous. Some lines of research are suggested, including Rb/Sr radiometric datings by the total rock method. Limited evidence based on the latter challenges the classic correlation of the Recôncavo Series with the Upper Jurassic-Lower Cretaceous. This is the case of the Dom João and the base of Rio da Serra stages, dated radiometrically as Triassic. Lastly, it is suggested that the base of the Albian Stage (i.e, the top of Alagoas Stage) coincides with the base of a distinctive, thick salt layer (Ibura Event) which is widely represented in basins Santos through Sergipe-Alagoas. This interpretation contrasts with the new tendency noted in some recent Brazilian papers, which place the Aptian-Albian boundary within post-evaporite marine (carbonatic shelf) sediments of those same basins, on the basis of microfossils, particularly planktonic foraminifera. This apparent contradiction could simply reflect the diachronous LADs of some index species. The magnitude of the evaporitic event in the South Atlantic proto-ocean (originated from the Tethys Sea to the north) could have triggered major paleoenvironmental disturbances in oceanic surface waters over much of the planet. A possible consequence of such changes was the faunal turnover noted in foraminiferal successions across the Aptian-Albian boundary, in its type section and elsewhere in the world.http://www.anuario.igeo.ufrj.br/2018_2/2018_2_276_296.pdfChronostratigraphyGeochronologyRecôncavo Series |
| spellingShingle | Rogério Loureiro Antunes Ricardo Latgé Milvard de Azevedo Janaína Teixeira Lobo Refletions on the Recôncavo Series, Brazil Anuário do Instituto de Geociências Chronostratigraphy Geochronology Recôncavo Series |
| title | Refletions on the Recôncavo Series, Brazil |
| title_full | Refletions on the Recôncavo Series, Brazil |
| title_fullStr | Refletions on the Recôncavo Series, Brazil |
| title_full_unstemmed | Refletions on the Recôncavo Series, Brazil |
| title_short | Refletions on the Recôncavo Series, Brazil |
| title_sort | refletions on the reconcavo series brazil |
| topic | Chronostratigraphy Geochronology Recôncavo Series |
| url | http://www.anuario.igeo.ufrj.br/2018_2/2018_2_276_296.pdf |
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