High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte

Detalhes bibliográficos
Autor(a) principal: Souza, T. G.L. [UNESP]
Data de Publicação: 2022
Outros Autores: Matos, S. A. [UNESP], Varejão, F. G., Rodrigues, M. G. [UNESP], Ribeiro, A. C., Freitas, B. T., Warren, L. V. [UNESP], Assine, M. L. [UNESP], Simões, M. G. [UNESP]
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://dx.doi.org/10.1016/j.palaeo.2022.110908
http://hdl.handle.net/11449/223591
Resumo: We report the Amargosa Biota from the middle part of the Lower Cretaceous Marizal Formation (Central Tucano Sub-Basin, NE Brazil), as a new Konservat-Lagerstätte. Exceptionally preserved fossils are confined to the lower part of an up to 15-m-thick, mud-dominated succession, named Amargosa Bed. Seven bedding planes (L0-L6) with distinct sedimentological and taphonomic attributes were identified in the type section (Amargosa Village, Euclides da Cunha County, Bahia State), distributed in an ~1-m-thick succession of well-laminated claystone, mudstone, siltstone, and very fine-grained sandstone. These contain ostracods, spinicaudatan carapaces, palaemonid shrimps, fish, and comminuted plant remains. Fossils occur in high concentration on at least four bedding planes (i.e., L2, L3, L5, and L6), forming polytypical assemblages that are dominated by one of the fossil groups. Assemblages are formed mainly by autochthonous to parautochthonous elements, representing variable, but limited, temporal mixing. A key attribute of some fossil-rich strata (L3, L5, and L6) is the preservation of poorly biomineralized organisms and/or of complete soft-bodied parts, which are typically prone to destruction due to rapid decay or bioturbation. The polytypical nature of these fossil assemblages, interbedded with non-fossiliferous intervals, suggests mass mortality events, probably caused by abrupt changes in water parameters (anoxia, salinity, pH, among others). The dark greenish gray color (yellowish when weathered), and the finely laminated nature of the claystone, siltstone, and mudstone containing members of the Amargosa Biota indicates that the benthic infaunal life was absent or, at least, very scarce in a locally, relatively deep, oxygen-poor lake bottom. Anoxia and high salinity, linked with local semi-arid conditions during the Lower Cretaceous may have played key roles in the exceptional preservation of some fossils (shrimps, fish). Finally, our data provide a more comprehensive understanding of the temporal distribution of taxa and taphonomic processes associated with the complex genesis of the fossil-bearing interval of the Amargosa Bed in its type locality.
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spelling High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-LagerstätteAptianExceptional fossilizationMarizal FormationPaleoenvironmentWe report the Amargosa Biota from the middle part of the Lower Cretaceous Marizal Formation (Central Tucano Sub-Basin, NE Brazil), as a new Konservat-Lagerstätte. Exceptionally preserved fossils are confined to the lower part of an up to 15-m-thick, mud-dominated succession, named Amargosa Bed. Seven bedding planes (L0-L6) with distinct sedimentological and taphonomic attributes were identified in the type section (Amargosa Village, Euclides da Cunha County, Bahia State), distributed in an ~1-m-thick succession of well-laminated claystone, mudstone, siltstone, and very fine-grained sandstone. These contain ostracods, spinicaudatan carapaces, palaemonid shrimps, fish, and comminuted plant remains. Fossils occur in high concentration on at least four bedding planes (i.e., L2, L3, L5, and L6), forming polytypical assemblages that are dominated by one of the fossil groups. Assemblages are formed mainly by autochthonous to parautochthonous elements, representing variable, but limited, temporal mixing. A key attribute of some fossil-rich strata (L3, L5, and L6) is the preservation of poorly biomineralized organisms and/or of complete soft-bodied parts, which are typically prone to destruction due to rapid decay or bioturbation. The polytypical nature of these fossil assemblages, interbedded with non-fossiliferous intervals, suggests mass mortality events, probably caused by abrupt changes in water parameters (anoxia, salinity, pH, among others). The dark greenish gray color (yellowish when weathered), and the finely laminated nature of the claystone, siltstone, and mudstone containing members of the Amargosa Biota indicates that the benthic infaunal life was absent or, at least, very scarce in a locally, relatively deep, oxygen-poor lake bottom. Anoxia and high salinity, linked with local semi-arid conditions during the Lower Cretaceous may have played key roles in the exceptional preservation of some fossils (shrimps, fish). Finally, our data provide a more comprehensive understanding of the temporal distribution of taxa and taphonomic processes associated with the complex genesis of the fossil-bearing interval of the Amargosa Bed in its type locality.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Departamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Avenida 24A 1515, SPInstituto de Biociências Universidade Estadual Paulista, Distrito de Rubião Júnior, SPDepartamento de Geologia Escola de Minas Universidade Federal de Ouro Preto, Morro do Cruzeiro, MGDepartamento de Biologia e Zoologia Universidade Federal de Mato Grosso, Avenida Fernando Corrêa da Costa 2367, MTFaculdade de Tecnologia Universidade Estadual de Campinas, Rua Paschoal Marmo 1888, SPDepartamento de Geologia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Avenida 24A 1515, SPInstituto de Biociências Universidade Estadual Paulista, Distrito de Rubião Júnior, SPFAPESP: 2017/20803-1Universidade Estadual Paulista (UNESP)Universidade Federal de Ouro PretoUniversidade Federal de Mato GrossoUniversidade Estadual de Campinas (UNICAMP)Souza, T. G.L. [UNESP]Matos, S. A. [UNESP]Varejão, F. G.Rodrigues, M. G. [UNESP]Ribeiro, A. C.Freitas, B. T.Warren, L. V. [UNESP]Assine, M. L. [UNESP]Simões, M. G. [UNESP]2022-04-28T19:51:32Z2022-04-28T19:51:32Z2022-04-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1016/j.palaeo.2022.110908Palaeogeography, Palaeoclimatology, Palaeoecology, v. 592.0031-0182http://hdl.handle.net/11449/22359110.1016/j.palaeo.2022.1109082-s2.0-85126007997Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengPalaeogeography, Palaeoclimatology, Palaeoecologyinfo:eu-repo/semantics/openAccess2022-04-28T19:51:32Zoai:repositorio.unesp.br:11449/223591Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T17:09:43.286601Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
title High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
spellingShingle High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
Souza, T. G.L. [UNESP]
Aptian
Exceptional fossilization
Marizal Formation
Paleoenvironment
title_short High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
title_full High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
title_fullStr High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
title_full_unstemmed High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
title_sort High-resolution taphonomy of the Lower Cretaceous “Amargosa Biota”, Central Tucano Sub-Basin, Bahia, Brazil: Implications for the paleoenvironmental dynamics of a new Konservat-Lagerstätte
author Souza, T. G.L. [UNESP]
author_facet Souza, T. G.L. [UNESP]
Matos, S. A. [UNESP]
Varejão, F. G.
Rodrigues, M. G. [UNESP]
Ribeiro, A. C.
Freitas, B. T.
Warren, L. V. [UNESP]
Assine, M. L. [UNESP]
Simões, M. G. [UNESP]
author_role author
author2 Matos, S. A. [UNESP]
Varejão, F. G.
Rodrigues, M. G. [UNESP]
Ribeiro, A. C.
Freitas, B. T.
Warren, L. V. [UNESP]
Assine, M. L. [UNESP]
Simões, M. G. [UNESP]
author2_role author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Universidade Estadual Paulista (UNESP)
Universidade Federal de Ouro Preto
Universidade Federal de Mato Grosso
Universidade Estadual de Campinas (UNICAMP)
dc.contributor.author.fl_str_mv Souza, T. G.L. [UNESP]
Matos, S. A. [UNESP]
Varejão, F. G.
Rodrigues, M. G. [UNESP]
Ribeiro, A. C.
Freitas, B. T.
Warren, L. V. [UNESP]
Assine, M. L. [UNESP]
Simões, M. G. [UNESP]
dc.subject.por.fl_str_mv Aptian
Exceptional fossilization
Marizal Formation
Paleoenvironment
topic Aptian
Exceptional fossilization
Marizal Formation
Paleoenvironment
description We report the Amargosa Biota from the middle part of the Lower Cretaceous Marizal Formation (Central Tucano Sub-Basin, NE Brazil), as a new Konservat-Lagerstätte. Exceptionally preserved fossils are confined to the lower part of an up to 15-m-thick, mud-dominated succession, named Amargosa Bed. Seven bedding planes (L0-L6) with distinct sedimentological and taphonomic attributes were identified in the type section (Amargosa Village, Euclides da Cunha County, Bahia State), distributed in an ~1-m-thick succession of well-laminated claystone, mudstone, siltstone, and very fine-grained sandstone. These contain ostracods, spinicaudatan carapaces, palaemonid shrimps, fish, and comminuted plant remains. Fossils occur in high concentration on at least four bedding planes (i.e., L2, L3, L5, and L6), forming polytypical assemblages that are dominated by one of the fossil groups. Assemblages are formed mainly by autochthonous to parautochthonous elements, representing variable, but limited, temporal mixing. A key attribute of some fossil-rich strata (L3, L5, and L6) is the preservation of poorly biomineralized organisms and/or of complete soft-bodied parts, which are typically prone to destruction due to rapid decay or bioturbation. The polytypical nature of these fossil assemblages, interbedded with non-fossiliferous intervals, suggests mass mortality events, probably caused by abrupt changes in water parameters (anoxia, salinity, pH, among others). The dark greenish gray color (yellowish when weathered), and the finely laminated nature of the claystone, siltstone, and mudstone containing members of the Amargosa Biota indicates that the benthic infaunal life was absent or, at least, very scarce in a locally, relatively deep, oxygen-poor lake bottom. Anoxia and high salinity, linked with local semi-arid conditions during the Lower Cretaceous may have played key roles in the exceptional preservation of some fossils (shrimps, fish). Finally, our data provide a more comprehensive understanding of the temporal distribution of taxa and taphonomic processes associated with the complex genesis of the fossil-bearing interval of the Amargosa Bed in its type locality.
publishDate 2022
dc.date.none.fl_str_mv 2022-04-28T19:51:32Z
2022-04-28T19:51:32Z
2022-04-15
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://dx.doi.org/10.1016/j.palaeo.2022.110908
Palaeogeography, Palaeoclimatology, Palaeoecology, v. 592.
0031-0182
http://hdl.handle.net/11449/223591
10.1016/j.palaeo.2022.110908
2-s2.0-85126007997
url http://dx.doi.org/10.1016/j.palaeo.2022.110908
http://hdl.handle.net/11449/223591
identifier_str_mv Palaeogeography, Palaeoclimatology, Palaeoecology, v. 592.
0031-0182
10.1016/j.palaeo.2022.110908
2-s2.0-85126007997
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv Palaeogeography, Palaeoclimatology, Palaeoecology
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.source.none.fl_str_mv Scopus
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
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