Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology

Detalhes bibliográficos
Autor(a) principal: SANTOS, João Orestes Schneider
Data de Publicação: 2003
Outros Autores: POTTER, Paul Edwin, REIS, Nelson Joaquim, HARTMANN, Léo Afraneo, FLETCHER, Ian Robert, McNAUGHTON, Neal J.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional de Geociências - RIGEO
Texto Completo: https://rigeo.cprm.gov.br/handle/doc/507
Resumo: New 207Pb/206Pb ion-microprobe dates from the basement underlying the Roraima Supergroup, from sandstones and tuffs within the supergroup, and from associated mafic intrusions establish new temporal framework for this major stratigraphic unit in northern South America. Zircons from the tuffs within the supergroup yield a Paleoproterozoic age of 1873 ± 3 Ma, Orosirian. The minimum age of the Roraima Supergroup was determined by U-Pb geochronology using baddeleyite and zircon from two mafic sills (Avanavero magmatism) and is 1782 ± 3 Ma. Zircons of some Roraima-like outliers indicate that they are post-Roraima in age and do not belong to the supergroup. This conclusion is supported by the unconformity between the Matauí and Uaimapué Formations present in the Pacaraima Plateau, which may represent a hiatus as long as 320 m.y. Thus, all the sandstones above the unconformity such as the Matauí Formation, as well as outliers such as the Serra Surucucus, Aracá, and Neblina units, do not belong to the supergroup. Rocks of the Roraima Supergroup and post-Roraima sandstones were deposited in two separate but overlapping basins, each 1,200,000 km2 in area. The Roraima Supergroup represents fill in a foreland basin that was derived mostly from the Trans-Amazon orogenic belt to the north and northeast, whereas the fill in the post-Roraima Neblina successor foreland basin was derived from both the Trans-Amazon and Tapajós-Parima orogenic belts to the east and northeast. Although most of both basins are largely flat lying or gently deformed, some of the westernmost outliers of the post-Roraima sandstones were deformed by the far-field effects of the Sunsás (Grenvillian) orogen at 1.33 Ga (Ar-Ar in muscovite). These results are based on U-Pb determinations of nine samples, Ar-Ar step-heating plateau age of one muscovite sample, and a complete review of many earlier Rb-Sr and K-Ar earlier dates
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spelling SANTOS, João Orestes SchneiderPOTTER, Paul EdwinREIS, Nelson JoaquimHARTMANN, Léo AfraneoFLETCHER, Ian RobertMcNAUGHTON, Neal J.2013-12-19T16:32:33Z2013-12-19T16:32:33Z2003SANTOS, João Orestes Schneider; POTTER, Paul Edwin; REIS, Nelson Joaquim; HARTMANN, Léo Afraneo; FLETCHER, Ian Robert; McNAUGHTON, Neal J. Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology. Geological Society of America Bulletin, Boulder, Co, v.115, n.3, p.331-348, Boulder, Co.https://rigeo.cprm.gov.br/handle/doc/507New 207Pb/206Pb ion-microprobe dates from the basement underlying the Roraima Supergroup, from sandstones and tuffs within the supergroup, and from associated mafic intrusions establish new temporal framework for this major stratigraphic unit in northern South America. Zircons from the tuffs within the supergroup yield a Paleoproterozoic age of 1873 ± 3 Ma, Orosirian. The minimum age of the Roraima Supergroup was determined by U-Pb geochronology using baddeleyite and zircon from two mafic sills (Avanavero magmatism) and is 1782 ± 3 Ma. Zircons of some Roraima-like outliers indicate that they are post-Roraima in age and do not belong to the supergroup. This conclusion is supported by the unconformity between the Matauí and Uaimapué Formations present in the Pacaraima Plateau, which may represent a hiatus as long as 320 m.y. Thus, all the sandstones above the unconformity such as the Matauí Formation, as well as outliers such as the Serra Surucucus, Aracá, and Neblina units, do not belong to the supergroup. Rocks of the Roraima Supergroup and post-Roraima sandstones were deposited in two separate but overlapping basins, each 1,200,000 km2 in area. The Roraima Supergroup represents fill in a foreland basin that was derived mostly from the Trans-Amazon orogenic belt to the north and northeast, whereas the fill in the post-Roraima Neblina successor foreland basin was derived from both the Trans-Amazon and Tapajós-Parima orogenic belts to the east and northeast. Although most of both basins are largely flat lying or gently deformed, some of the westernmost outliers of the post-Roraima sandstones were deformed by the far-field effects of the Sunsás (Grenvillian) orogen at 1.33 Ga (Ar-Ar in muscovite). These results are based on U-Pb determinations of nine samples, Ar-Ar step-heating plateau age of one muscovite sample, and a complete review of many earlier Rb-Sr and K-Ar earlier datesGEOCRONOLOGIAESTRATIGRAFIAGEOLOGIA ESTRUTURALBRASILRORAIMAAge, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronologyinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleGeological Society of America BulletinwhiteA versão pdf do editor não pode ser utilizadainfo:eu-repo/semantics/openAccessBoulder, Coengreponame:Repositório Institucional de Geociências - RIGEOinstname:Companhia de Pesquisa de Recursos Minerais (CPRM)instacron:CPRMTEXTart_santos.pdf.txtart_santos.pdf.txtExtracted texttext/plain102313http://rigeo.cprm.gov.br/jspui/bitstream/doc/507/2/art_santos.pdf.txt9d121cac1cc561ca13a7134da28a1906MD52THUMBNAILart_santos.pdf.jpgart_santos.pdf.jpgGenerated Thumbnailimage/jpeg1767http://rigeo.cprm.gov.br/jspui/bitstream/doc/507/3/art_santos.pdf.jpg3bfe1e39c65c47830f683b60036bd707MD53ORIGINALart_santos.pdfart_santos.pdfproducao cientificaapplication/pdf3979330http://rigeo.cprm.gov.br/jspui/bitstream/doc/507/1/art_santos.pdff93ce8d836934888973256ce61bc41c7MD51doc/5072023-02-13 11:10:49.088oai:rigeo.sgb.gov.br:doc/507Repositório InstitucionalONGhttps://rigeo.sgb.gov.br/oai/request https://rigeo.cprm.gov.br/oai/requestrigeo@sgb.gov.bropendoar:2023-02-13T14:10:49Repositório Institucional de Geociências - RIGEO - Companhia de Pesquisa de Recursos Minerais (CPRM)false
dc.title.none.fl_str_mv Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
title Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
spellingShingle Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
SANTOS, João Orestes Schneider
GEOCRONOLOGIA
ESTRATIGRAFIA
GEOLOGIA ESTRUTURAL
BRASIL
RORAIMA
title_short Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
title_full Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
title_fullStr Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
title_full_unstemmed Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
title_sort Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology
author SANTOS, João Orestes Schneider
author_facet SANTOS, João Orestes Schneider
POTTER, Paul Edwin
REIS, Nelson Joaquim
HARTMANN, Léo Afraneo
FLETCHER, Ian Robert
McNAUGHTON, Neal J.
author_role author
author2 POTTER, Paul Edwin
REIS, Nelson Joaquim
HARTMANN, Léo Afraneo
FLETCHER, Ian Robert
McNAUGHTON, Neal J.
author2_role author
author
author
author
author
dc.contributor.author.fl_str_mv SANTOS, João Orestes Schneider
POTTER, Paul Edwin
REIS, Nelson Joaquim
HARTMANN, Léo Afraneo
FLETCHER, Ian Robert
McNAUGHTON, Neal J.
dc.subject.por.fl_str_mv GEOCRONOLOGIA
ESTRATIGRAFIA
GEOLOGIA ESTRUTURAL
BRASIL
RORAIMA
topic GEOCRONOLOGIA
ESTRATIGRAFIA
GEOLOGIA ESTRUTURAL
BRASIL
RORAIMA
description New 207Pb/206Pb ion-microprobe dates from the basement underlying the Roraima Supergroup, from sandstones and tuffs within the supergroup, and from associated mafic intrusions establish new temporal framework for this major stratigraphic unit in northern South America. Zircons from the tuffs within the supergroup yield a Paleoproterozoic age of 1873 ± 3 Ma, Orosirian. The minimum age of the Roraima Supergroup was determined by U-Pb geochronology using baddeleyite and zircon from two mafic sills (Avanavero magmatism) and is 1782 ± 3 Ma. Zircons of some Roraima-like outliers indicate that they are post-Roraima in age and do not belong to the supergroup. This conclusion is supported by the unconformity between the Matauí and Uaimapué Formations present in the Pacaraima Plateau, which may represent a hiatus as long as 320 m.y. Thus, all the sandstones above the unconformity such as the Matauí Formation, as well as outliers such as the Serra Surucucus, Aracá, and Neblina units, do not belong to the supergroup. Rocks of the Roraima Supergroup and post-Roraima sandstones were deposited in two separate but overlapping basins, each 1,200,000 km2 in area. The Roraima Supergroup represents fill in a foreland basin that was derived mostly from the Trans-Amazon orogenic belt to the north and northeast, whereas the fill in the post-Roraima Neblina successor foreland basin was derived from both the Trans-Amazon and Tapajós-Parima orogenic belts to the east and northeast. Although most of both basins are largely flat lying or gently deformed, some of the westernmost outliers of the post-Roraima sandstones were deformed by the far-field effects of the Sunsás (Grenvillian) orogen at 1.33 Ga (Ar-Ar in muscovite). These results are based on U-Pb determinations of nine samples, Ar-Ar step-heating plateau age of one muscovite sample, and a complete review of many earlier Rb-Sr and K-Ar earlier dates
publishDate 2003
dc.date.issued.fl_str_mv 2003
dc.date.accessioned.fl_str_mv 2013-12-19T16:32:33Z
dc.date.available.fl_str_mv 2013-12-19T16:32:33Z
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dc.identifier.citation.fl_str_mv SANTOS, João Orestes Schneider; POTTER, Paul Edwin; REIS, Nelson Joaquim; HARTMANN, Léo Afraneo; FLETCHER, Ian Robert; McNAUGHTON, Neal J. Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology. Geological Society of America Bulletin, Boulder, Co, v.115, n.3, p.331-348, Boulder, Co.
dc.identifier.uri.fl_str_mv https://rigeo.cprm.gov.br/handle/doc/507
identifier_str_mv SANTOS, João Orestes Schneider; POTTER, Paul Edwin; REIS, Nelson Joaquim; HARTMANN, Léo Afraneo; FLETCHER, Ian Robert; McNAUGHTON, Neal J. Age, source and regional stratigraphy of the Roraima Supergroup and Roraima-like outliers in northern South America based on U-Pb gechronology. Geological Society of America Bulletin, Boulder, Co, v.115, n.3, p.331-348, Boulder, Co.
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