Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America

Detalhes bibliográficos
Autor(a) principal: Azmy, Karem
Data de Publicação: 2006
Outros Autores: Kaufman, Alan J., Misi, Aroldo, Oliveira, Tolentino Flávio de
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UFBA
Texto Completo: http://www.repositorio.ufba.br/ri/handle/ri/6394
Resumo: RESTRITO
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spelling Azmy, KaremKaufman, Alan J.Misi, AroldoOliveira, Tolentino Flávio deAzmy, KaremKaufman, Alan J.Misi, AroldoOliveira, Tolentino Flávio de2012-07-10T15:35:46Z2012-07-10T15:35:46Z20060301-9268http://www.repositorio.ufba.br/ri/handle/ri/6394v.149, n.3-4RESTRITOThe Lapa Formation is a thick carbonate sequence (∼900 m) that constitutes the upper part of the Vazante Group on the São Francisco craton, Brazil. It conformably overlies a previously unrecognized glacial diamictite unit of poorly constrained age. The sequence, above the glacial unconformity, consists predominantly of organic-rich shale, subtidal rhythmic dolomicrites and microbialaminites, and intertidal stromatolites. Four boreholes, spanning different depositional settings, were sampled at high-resolution and investigated for their petrographic and chemical criteria to evaluate their degree of preservation. The δ13C and δ18O values of well preserved Lapa carbonate microsamples range from −8.2‰ to 3.3‰ (VPDB) and from −13.6‰ to −0.9‰ (VPDB), respectively. Each of the δ13C profiles of the investigated cores reveals two strong negative excursions of up to 8‰, an event in post-glacial dolomicrites immediately above the glaciogenic unit and a 10 m interval of organic-rich shale, and a second near the top of the sequence associated with a shale interval. Based on the observation of dropstones and sedimentary iron formation in the underlying diamictite, as well as the distinguishable carbon isotope trends, the Lapa Formation is considered as a cap carbonate lithofacies. The age of the Lapa Formation is presently unknown but the least radiogenic 87Sr/86Sr value (∼0.7068), associated with a negative carbon isotope excursion, matches that from the Rasthof Formation in Namiba on the Congo craton, which is radiometrically constrained to be younger than ca. 750 Ma.Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2012-07-10T15:35:46Z No. of bitstreams: 1 GG.pdf: 1133804 bytes, checksum: ae51a47d0d030047211f4318f71000f0 (MD5)Made available in DSpace on 2012-07-10T15:35:46Z (GMT). No. of bitstreams: 1 GG.pdf: 1133804 bytes, checksum: ae51a47d0d030047211f4318f71000f0 (MD5) Previous issue date: 2006Precambrian Researchhttp://dx.doi.org/10.1016/j.precamres.2006.07.001reponame:Repositório Institucional da UFBAinstname:Universidade Federal da Bahia (UFBA)instacron:UFBANeoproterozoic carbonatesStable isotope stratigraphyLapa FormationBrazilIsotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South AmericaPrecambrian Researchinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleenginfo:eu-repo/semantics/openAccessORIGINALGG.pdfGG.pdfapplication/pdf1133804https://repositorio.ufba.br/bitstream/ri/6394/1/GG.pdfae51a47d0d030047211f4318f71000f0MD51LICENSElicense.txtlicense.txttext/plain1762https://repositorio.ufba.br/bitstream/ri/6394/2/license.txt1b89a9a0548218172d7c829f87a0eab9MD52TEXTGG.pdf.txtGG.pdf.txtExtracted texttext/plain53630https://repositorio.ufba.br/bitstream/ri/6394/3/GG.pdf.txta86498df120e1a0cd6932ebee69d2b27MD53ri/63942022-07-05 14:03:13.516oai:repositorio.ufba.br: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Repositório InstitucionalPUBhttp://192.188.11.11:8080/oai/requestopendoar:19322022-07-05T17:03:13Repositório Institucional da UFBA - Universidade Federal da Bahia (UFBA)false
dc.title.pt_BR.fl_str_mv Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
dc.title.alternative.pt_BR.fl_str_mv Precambrian Research
title Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
spellingShingle Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
Azmy, Karem
Neoproterozoic carbonates
Stable isotope stratigraphy
Lapa Formation
Brazil
title_short Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
title_full Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
title_fullStr Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
title_full_unstemmed Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
title_sort Isotope stratigraphy of the Lapa Formation, São Francisco Basin, Brazil: Implications for Late Neoproterozoic glacial events in South America
author Azmy, Karem
author_facet Azmy, Karem
Kaufman, Alan J.
Misi, Aroldo
Oliveira, Tolentino Flávio de
author_role author
author2 Kaufman, Alan J.
Misi, Aroldo
Oliveira, Tolentino Flávio de
author2_role author
author
author
dc.contributor.author.fl_str_mv Azmy, Karem
Kaufman, Alan J.
Misi, Aroldo
Oliveira, Tolentino Flávio de
Azmy, Karem
Kaufman, Alan J.
Misi, Aroldo
Oliveira, Tolentino Flávio de
dc.subject.por.fl_str_mv Neoproterozoic carbonates
Stable isotope stratigraphy
Lapa Formation
Brazil
topic Neoproterozoic carbonates
Stable isotope stratigraphy
Lapa Formation
Brazil
description RESTRITO
publishDate 2006
dc.date.issued.fl_str_mv 2006
dc.date.accessioned.fl_str_mv 2012-07-10T15:35:46Z
dc.date.available.fl_str_mv 2012-07-10T15:35:46Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
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status_str publishedVersion
dc.identifier.uri.fl_str_mv http://www.repositorio.ufba.br/ri/handle/ri/6394
dc.identifier.issn.none.fl_str_mv 0301-9268
dc.identifier.number.pt_BR.fl_str_mv v.149, n.3-4
identifier_str_mv 0301-9268
v.149, n.3-4
url http://www.repositorio.ufba.br/ri/handle/ri/6394
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Precambrian Research
publisher.none.fl_str_mv Precambrian Research
dc.source.pt_BR.fl_str_mv http://dx.doi.org/10.1016/j.precamres.2006.07.001
dc.source.none.fl_str_mv reponame:Repositório Institucional da UFBA
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reponame_str Repositório Institucional da UFBA
collection Repositório Institucional da UFBA
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