The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy
This paper presents a thorough analysis of foraminiferal assemblages ranging in age from the Bedoulian-Gargasian transition to the middle Gargasian in the Cassis-La Bédoule area (SE France), the historical stratotype of the Lower Aptian substage. This region is particularly suitable for detailed stu...
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Association Carnets de Geologie
2005
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ftdoajarticles:oai:doaj.org/article:e41cc3412a604d1580aff958d1e391dd 2023-10-01T03:59:01+02:00 The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy Bellier Jean-Pierre Tronchetti Guy Moullade Michel 2005-04-01T00:00:00Z https://doaj.org/article/e41cc3412a604d1580aff958d1e391dd EN FR eng fre Association Carnets de Geologie http://paleopolis.rediris.es/cg/CG2005_A02/index.html https://doaj.org/toc/1765-2553 https://doaj.org/toc/1634-0744 1765-2553 1634-0744 https://doaj.org/article/e41cc3412a604d1580aff958d1e391dd Carnets de Géologie, Vol CG2005, p A02 (2005) Early Cretaceous Aptian historical stratotype Foraminifera biostratigraphy taxonomy evolution Geology QE1-996.5 Paleontology QE701-760 Stratigraphy QE640-699 article 2005 ftdoajarticles 2023-09-03T00:38:27Z This paper presents a thorough analysis of foraminiferal assemblages ranging in age from the Bedoulian-Gargasian transition to the middle Gargasian in the Cassis-La Bédoule area (SE France), the historical stratotype of the Lower Aptian substage. This region is particularly suitable for detailed studies of Aptian foraminifera owing to rapid and continuous sediment depositional rates and well-diversified microfaunas. The ranges of benthic forms appear to be fairly stable but some species (Praedorothia praeoxycona, Lenticulina cf. nodosa, Astacolus crepidularis, Globorotalites bartensteini) become extinct at the end of the Bedoulian and thus can be used to separate this substage from the Gargasian. The stratotypic area also offers an opportunity to follow the evolution of planktonic forms step by step at a crucial period of their history, when modalities of speciation and phylogenetic relationships appear to be particularly complex. The important morphologic variability of Aptian planktonic foraminifera does not help finding stable stratigraphic markers; nevertheless, we are able to propose a biozonation comprising five zones (Cabri, Luterbacheri, Ferreolensis, Barri, Algerianus) for the interval under consideration, usually subdivided into three zones. Our study of foraminiferal assemblages and species took into account the range of variability among populations and not just the characteristics of a single specimen, such as the holotype. As a result this paper provides new taxonomic precisions on certain planktonic species hitherto controversial or possibly of doubtful validity. Article in Journal/Newspaper Planktonic foraminifera Directory of Open Access Journals: DOAJ Articles |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English French |
topic |
Early Cretaceous Aptian historical stratotype Foraminifera biostratigraphy taxonomy evolution Geology QE1-996.5 Paleontology QE701-760 Stratigraphy QE640-699 |
spellingShingle |
Early Cretaceous Aptian historical stratotype Foraminifera biostratigraphy taxonomy evolution Geology QE1-996.5 Paleontology QE701-760 Stratigraphy QE640-699 Bellier Jean-Pierre Tronchetti Guy Moullade Michel The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy |
topic_facet |
Early Cretaceous Aptian historical stratotype Foraminifera biostratigraphy taxonomy evolution Geology QE1-996.5 Paleontology QE701-760 Stratigraphy QE640-699 |
description |
This paper presents a thorough analysis of foraminiferal assemblages ranging in age from the Bedoulian-Gargasian transition to the middle Gargasian in the Cassis-La Bédoule area (SE France), the historical stratotype of the Lower Aptian substage. This region is particularly suitable for detailed studies of Aptian foraminifera owing to rapid and continuous sediment depositional rates and well-diversified microfaunas. The ranges of benthic forms appear to be fairly stable but some species (Praedorothia praeoxycona, Lenticulina cf. nodosa, Astacolus crepidularis, Globorotalites bartensteini) become extinct at the end of the Bedoulian and thus can be used to separate this substage from the Gargasian. The stratotypic area also offers an opportunity to follow the evolution of planktonic forms step by step at a crucial period of their history, when modalities of speciation and phylogenetic relationships appear to be particularly complex. The important morphologic variability of Aptian planktonic foraminifera does not help finding stable stratigraphic markers; nevertheless, we are able to propose a biozonation comprising five zones (Cabri, Luterbacheri, Ferreolensis, Barri, Algerianus) for the interval under consideration, usually subdivided into three zones. Our study of foraminiferal assemblages and species took into account the range of variability among populations and not just the characteristics of a single specimen, such as the holotype. As a result this paper provides new taxonomic precisions on certain planktonic species hitherto controversial or possibly of doubtful validity. |
format |
Article in Journal/Newspaper |
author |
Bellier Jean-Pierre Tronchetti Guy Moullade Michel |
author_facet |
Bellier Jean-Pierre Tronchetti Guy Moullade Michel |
author_sort |
Bellier Jean-Pierre |
title |
The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy |
title_short |
The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy |
title_full |
The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy |
title_fullStr |
The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy |
title_full_unstemmed |
The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy |
title_sort |
gargasian (middle aptian) strata from cassis-la bédoule (lower aptian historical stratotype, se france): planktonic and benthic foraminiferal assemblages and biostratigraphy |
publisher |
Association Carnets de Geologie |
publishDate |
2005 |
url |
https://doaj.org/article/e41cc3412a604d1580aff958d1e391dd |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_source |
Carnets de Géologie, Vol CG2005, p A02 (2005) |
op_relation |
http://paleopolis.rediris.es/cg/CG2005_A02/index.html https://doaj.org/toc/1765-2553 https://doaj.org/toc/1634-0744 1765-2553 1634-0744 https://doaj.org/article/e41cc3412a604d1580aff958d1e391dd |
_version_ |
1778532422297583616 |