Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin
The nanoflora and microfauna from the Agrio Formation are analyzed in three different areas of the Neuquén Basin to establish its age and paleonvironmental variations. In the northern area of the basin, the oldest Agrio Fomation sedimentites are recognized and assigned to the Lower Valanginian throu...
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I28-R145-paper_00044822_v65_n2_p342_Concheyro_oai2024-08-16 Concheyro, A. Lescano, M. Caramés, A. Ballent, S. 2009 The nanoflora and microfauna from the Agrio Formation are analyzed in three different areas of the Neuquén Basin to establish its age and paleonvironmental variations. In the northern area of the basin, the oldest Agrio Fomation sedimentites are recognized and assigned to the Lower Valanginian through ammonites. A monospecific Epistomina loncochensis Ballent microfauna is recovered from these levels, which indicates disoxic environments. Up to the top of the section, siltstones contain a diverse foraminifera microfauna of normal shelves, which are replaced by an impoverished fauna related to shallowing processes. The age defined by calcareous nannofossils is Late Valanginian-Late Hauterivian. In the central and southern position of the Neuquén Basin, the nannofossil assemblages indicate the Upper Valanginian-Upper Hauterivian for the Agrio Formation. The benthic microfauna suggests frequent eustatic variations ranging from shelves to shallow marine environments. In the austral sector of the basin, a poorly diversified foraminiferal assemblage is recorded and a high ostracods/foraminifera ratio indicates a restricted marine environment, and normal salinity. The presence of a level with abundant attached foraminifera indicates high energy episodes. The high diversified Platycopida ostracods suggest warm-temperate to subtropical waters. Fil:Concheyro, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Lescano, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Caramés, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. application/pdf http://hdl.handle.net/20.500.12110/paper_00044822_v65_n2_p342_Concheyro info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Rev. Asoc. Geol. Argent. 2009;65(2):342-361 Argentina Biostratigraphy Mesozoic Microfossils Nannofossils Paleoecology biostratigraphy calcareous alga fauna foraminifera fossil assemblage Mesozoic microfossil micropaleontology paleoecology paleoenvironment Argentina Neuquen Basin Epistomina Foraminifera Ostracoda Platycopida Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v65_n2_p342_Concheyro_oai |
institution |
Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-145 |
collection |
Repositorio Digital de la Universidad de Buenos Aires (UBA) |
topic |
Argentina Biostratigraphy Mesozoic Microfossils Nannofossils Paleoecology biostratigraphy calcareous alga fauna foraminifera fossil assemblage Mesozoic microfossil micropaleontology paleoecology paleoenvironment Argentina Neuquen Basin Epistomina Foraminifera Ostracoda Platycopida |
spellingShingle |
Argentina Biostratigraphy Mesozoic Microfossils Nannofossils Paleoecology biostratigraphy calcareous alga fauna foraminifera fossil assemblage Mesozoic microfossil micropaleontology paleoecology paleoenvironment Argentina Neuquen Basin Epistomina Foraminifera Ostracoda Platycopida Concheyro, A. Lescano, M. Caramés, A. Ballent, S. Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin |
topic_facet |
Argentina Biostratigraphy Mesozoic Microfossils Nannofossils Paleoecology biostratigraphy calcareous alga fauna foraminifera fossil assemblage Mesozoic microfossil micropaleontology paleoecology paleoenvironment Argentina Neuquen Basin Epistomina Foraminifera Ostracoda Platycopida |
description |
The nanoflora and microfauna from the Agrio Formation are analyzed in three different areas of the Neuquén Basin to establish its age and paleonvironmental variations. In the northern area of the basin, the oldest Agrio Fomation sedimentites are recognized and assigned to the Lower Valanginian through ammonites. A monospecific Epistomina loncochensis Ballent microfauna is recovered from these levels, which indicates disoxic environments. Up to the top of the section, siltstones contain a diverse foraminifera microfauna of normal shelves, which are replaced by an impoverished fauna related to shallowing processes. The age defined by calcareous nannofossils is Late Valanginian-Late Hauterivian. In the central and southern position of the Neuquén Basin, the nannofossil assemblages indicate the Upper Valanginian-Upper Hauterivian for the Agrio Formation. The benthic microfauna suggests frequent eustatic variations ranging from shelves to shallow marine environments. In the austral sector of the basin, a poorly diversified foraminiferal assemblage is recorded and a high ostracods/foraminifera ratio indicates a restricted marine environment, and normal salinity. The presence of a level with abundant attached foraminifera indicates high energy episodes. The high diversified Platycopida ostracods suggest warm-temperate to subtropical waters. |
format |
Artículo Artículo publishedVersion |
author |
Concheyro, A. Lescano, M. Caramés, A. Ballent, S. |
author_facet |
Concheyro, A. Lescano, M. Caramés, A. Ballent, S. |
author_sort |
Concheyro, A. |
title |
Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin |
title_short |
Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin |
title_full |
Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin |
title_fullStr |
Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin |
title_full_unstemmed |
Micropaleontology of the Agrio Formation (Lower Cretaceous) in different areas of the Neuquén Basin |
title_sort |
micropaleontology of the agrio formation (lower cretaceous) in different areas of the neuquén basin |
publishDate |
2009 |
url |
http://hdl.handle.net/20.500.12110/paper_00044822_v65_n2_p342_Concheyro https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00044822_v65_n2_p342_Concheyro_oai |
work_keys_str_mv |
AT concheyroa micropaleontologyoftheagrioformationlowercretaceousindifferentareasoftheneuquenbasin AT lescanom micropaleontologyoftheagrioformationlowercretaceousindifferentareasoftheneuquenbasin AT caramesa micropaleontologyoftheagrioformationlowercretaceousindifferentareasoftheneuquenbasin AT ballents micropaleontologyoftheagrioformationlowercretaceousindifferentareasoftheneuquenbasin |
_version_ |
1809356764833906688 |