Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Outros Autores: | , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1016/j.gca.2020.01.035 http://hdl.handle.net/11449/197682 |
Resumo: | The Jacobina Basin has a well-preserved sedimentary record, including continental and marine deposits, and hosts Au-(U)Py mineralization in metaconglomerate beds similar to the Witwatersrand gold province. Based on petrographic observations, in situ trace-elements, and multiple sulfur isotope analyses (S-32, S-33, S-34, and S-36) on pyrite from alluvial and marine facies, several types of pyrite were recognized. The pyrite grains identified in the alluvial metaconglomerates resemble those found in several pre-GOE gold-bearing metaconglomerates, including detrital and epigenetic varieties. Detrital inclusion-bearing pyrite is enriched in several redox-sensitive trace-metals as well as Au, which indicate an association with carbonaceous shales. On the other hand, the sources of detrital massive pyrite are more variable and include igneous, metamorphic, and hydrothermal sources from the Paleoarchean hinterland of Jacobina Basin. Epigenetic pyrite in metaconglomerates formed during metamorphism by the recrystallization of detrital pyrite with negligible contributions from external hydrothermal fluids to the basin. Diagenetic and epigenetic pyrite are found in marine lithologies. In a metapelite sample, the pyrite grains formed near the sediment-water column interface, with S sourced from the photolytic sulfate (SO42-, D Delta S-33 < 0) dissolved in the water column. A quartzite sample, in turn, has detrital pyrite grains that were likely reworked from continental deposits, as well as pyrite formed by the assimilation of elemental sulfur (S-8, Delta S-33 > 0) that accumulated in sediment pore water during diagenesis. Significantly, the pyrite associated with terrestrial metasediments shows a wide range in delta S-34 values but quite restricted ranges in Delta S-33 and Delta S-36 values, whereas pyrite associated with the marine metasedimentary rocks exhibits limited delta S-34 values but has a wide range in Delta S-33 values and correlated Delta S-36 values close to the Archean array. These data suggest distinct preservation routes for MIF-S from atmospheric SO42- and S-8 in terrestrial and marine environments. Conditions on the terrestrial surface resulted in re-equilibration of distinct S sources, diminishing the amplitude of the Archean atmospheric signal. In contrast, SO42- dissolved in shallow marine settings while S-8 settled to the floor, favoring the preservation of MIF-S isotopic signatures. Such processes may also explain the apparent differences in interpretations of atmospheric conditions derived from uncharacterized pyrites from Archean sources. Our data suggest that the Earth's atmosphere remained anoxic, and terrestrial conditions were such as to allow the syngenetic accumulation of gold, as recently proposed for the Witwatersrand gold deposits. (C) 2020 Elsevier Ltd. All rights reserved. |
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Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) depositsAu-U-pyrite mineralizationMultiple sulfur isotopesJacobina BasinSao Francisco CratonThe Jacobina Basin has a well-preserved sedimentary record, including continental and marine deposits, and hosts Au-(U)Py mineralization in metaconglomerate beds similar to the Witwatersrand gold province. Based on petrographic observations, in situ trace-elements, and multiple sulfur isotope analyses (S-32, S-33, S-34, and S-36) on pyrite from alluvial and marine facies, several types of pyrite were recognized. The pyrite grains identified in the alluvial metaconglomerates resemble those found in several pre-GOE gold-bearing metaconglomerates, including detrital and epigenetic varieties. Detrital inclusion-bearing pyrite is enriched in several redox-sensitive trace-metals as well as Au, which indicate an association with carbonaceous shales. On the other hand, the sources of detrital massive pyrite are more variable and include igneous, metamorphic, and hydrothermal sources from the Paleoarchean hinterland of Jacobina Basin. Epigenetic pyrite in metaconglomerates formed during metamorphism by the recrystallization of detrital pyrite with negligible contributions from external hydrothermal fluids to the basin. Diagenetic and epigenetic pyrite are found in marine lithologies. In a metapelite sample, the pyrite grains formed near the sediment-water column interface, with S sourced from the photolytic sulfate (SO42-, D Delta S-33 < 0) dissolved in the water column. A quartzite sample, in turn, has detrital pyrite grains that were likely reworked from continental deposits, as well as pyrite formed by the assimilation of elemental sulfur (S-8, Delta S-33 > 0) that accumulated in sediment pore water during diagenesis. Significantly, the pyrite associated with terrestrial metasediments shows a wide range in delta S-34 values but quite restricted ranges in Delta S-33 and Delta S-36 values, whereas pyrite associated with the marine metasedimentary rocks exhibits limited delta S-34 values but has a wide range in Delta S-33 values and correlated Delta S-36 values close to the Archean array. These data suggest distinct preservation routes for MIF-S from atmospheric SO42- and S-8 in terrestrial and marine environments. Conditions on the terrestrial surface resulted in re-equilibration of distinct S sources, diminishing the amplitude of the Archean atmospheric signal. In contrast, SO42- dissolved in shallow marine settings while S-8 settled to the floor, favoring the preservation of MIF-S isotopic signatures. Such processes may also explain the apparent differences in interpretations of atmospheric conditions derived from uncharacterized pyrites from Archean sources. Our data suggest that the Earth's atmosphere remained anoxic, and terrestrial conditions were such as to allow the syngenetic accumulation of gold, as recently proposed for the Witwatersrand gold deposits. (C) 2020 Elsevier Ltd. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Australian Research Council - ARCUniv Fed Campina Grande, Unidade Acad Mineracao & Geol, Campina Grande, Paraiba, BrazilUniv Brasilia, Programa Posgrad Geol, Brasilia, DF, BrazilUniv Vale Rio dos Sinos, Programa Posgrad Geol, Sao Leopoldo, BrazilAustralian Natl Univ, Res Sch Earth Sci, Canberra, ACT 2601, AustraliaUniv Fed Sao Carlos, Dept Fis Quim & Matemat, Sorocaba, BrazilUniv Estadual Paulista, Dept Fis, Presidente Prudente, BrazilUniv Estadual Paulista, Dept Fis, Presidente Prudente, BrazilCNPq: 163459/2013-4CNPq: 202267/2014-8Australian Research Council - ARC: DP140103393Elsevier B.V.Univ Fed Campina GrandeUniversidade de Brasília (UnB)Univ Vale Rio dos SinosAustralian Natl UnivUniversidade Federal de São Carlos (UFSCar)Universidade Estadual Paulista (Unesp)Teles, Guilherme S.Chemale Jr, FaridAvila, Janaina N.Ireland, Trevor R.Dias, Airton N. C.Cruz, Daniele C. F.Constantino, Carlos J. L. [UNESP]2020-12-11T09:37:44Z2020-12-11T09:37:44Z2020-03-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article331-353http://dx.doi.org/10.1016/j.gca.2020.01.035Geochimica Et Cosmochimica Acta. Oxford: Pergamon-elsevier Science Ltd, v. 273, p. 331-353, 2020.0016-7037http://hdl.handle.net/11449/19768210.1016/j.gca.2020.01.035WOS:000514832600019Web of Sciencereponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengGeochimica Et Cosmochimica Actainfo:eu-repo/semantics/openAccess2024-06-19T12:44:50Zoai:repositorio.unesp.br:11449/197682Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T22:45:08.796601Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
title |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
spellingShingle |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits Teles, Guilherme S. Au-U-pyrite mineralization Multiple sulfur isotopes Jacobina Basin Sao Francisco Craton |
title_short |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
title_full |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
title_fullStr |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
title_full_unstemmed |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
title_sort |
Textural and geochemical investigation of pyrite in Jacobina Basin, Sao Francisco Craton, Brazil: Implications for paleoenvironmental conditions and formation of pre-GOE metaconglomerate-hosted Au-(U) deposits |
author |
Teles, Guilherme S. |
author_facet |
Teles, Guilherme S. Chemale Jr, Farid Avila, Janaina N. Ireland, Trevor R. Dias, Airton N. C. Cruz, Daniele C. F. Constantino, Carlos J. L. [UNESP] |
author_role |
author |
author2 |
Chemale Jr, Farid Avila, Janaina N. Ireland, Trevor R. Dias, Airton N. C. Cruz, Daniele C. F. Constantino, Carlos J. L. [UNESP] |
author2_role |
author author author author author author |
dc.contributor.none.fl_str_mv |
Univ Fed Campina Grande Universidade de Brasília (UnB) Univ Vale Rio dos Sinos Australian Natl Univ Universidade Federal de São Carlos (UFSCar) Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Teles, Guilherme S. Chemale Jr, Farid Avila, Janaina N. Ireland, Trevor R. Dias, Airton N. C. Cruz, Daniele C. F. Constantino, Carlos J. L. [UNESP] |
dc.subject.por.fl_str_mv |
Au-U-pyrite mineralization Multiple sulfur isotopes Jacobina Basin Sao Francisco Craton |
topic |
Au-U-pyrite mineralization Multiple sulfur isotopes Jacobina Basin Sao Francisco Craton |
description |
The Jacobina Basin has a well-preserved sedimentary record, including continental and marine deposits, and hosts Au-(U)Py mineralization in metaconglomerate beds similar to the Witwatersrand gold province. Based on petrographic observations, in situ trace-elements, and multiple sulfur isotope analyses (S-32, S-33, S-34, and S-36) on pyrite from alluvial and marine facies, several types of pyrite were recognized. The pyrite grains identified in the alluvial metaconglomerates resemble those found in several pre-GOE gold-bearing metaconglomerates, including detrital and epigenetic varieties. Detrital inclusion-bearing pyrite is enriched in several redox-sensitive trace-metals as well as Au, which indicate an association with carbonaceous shales. On the other hand, the sources of detrital massive pyrite are more variable and include igneous, metamorphic, and hydrothermal sources from the Paleoarchean hinterland of Jacobina Basin. Epigenetic pyrite in metaconglomerates formed during metamorphism by the recrystallization of detrital pyrite with negligible contributions from external hydrothermal fluids to the basin. Diagenetic and epigenetic pyrite are found in marine lithologies. In a metapelite sample, the pyrite grains formed near the sediment-water column interface, with S sourced from the photolytic sulfate (SO42-, D Delta S-33 < 0) dissolved in the water column. A quartzite sample, in turn, has detrital pyrite grains that were likely reworked from continental deposits, as well as pyrite formed by the assimilation of elemental sulfur (S-8, Delta S-33 > 0) that accumulated in sediment pore water during diagenesis. Significantly, the pyrite associated with terrestrial metasediments shows a wide range in delta S-34 values but quite restricted ranges in Delta S-33 and Delta S-36 values, whereas pyrite associated with the marine metasedimentary rocks exhibits limited delta S-34 values but has a wide range in Delta S-33 values and correlated Delta S-36 values close to the Archean array. These data suggest distinct preservation routes for MIF-S from atmospheric SO42- and S-8 in terrestrial and marine environments. Conditions on the terrestrial surface resulted in re-equilibration of distinct S sources, diminishing the amplitude of the Archean atmospheric signal. In contrast, SO42- dissolved in shallow marine settings while S-8 settled to the floor, favoring the preservation of MIF-S isotopic signatures. Such processes may also explain the apparent differences in interpretations of atmospheric conditions derived from uncharacterized pyrites from Archean sources. Our data suggest that the Earth's atmosphere remained anoxic, and terrestrial conditions were such as to allow the syngenetic accumulation of gold, as recently proposed for the Witwatersrand gold deposits. (C) 2020 Elsevier Ltd. All rights reserved. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-12-11T09:37:44Z 2020-12-11T09:37:44Z 2020-03-15 |
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.gca.2020.01.035 Geochimica Et Cosmochimica Acta. Oxford: Pergamon-elsevier Science Ltd, v. 273, p. 331-353, 2020. 0016-7037 http://hdl.handle.net/11449/197682 10.1016/j.gca.2020.01.035 WOS:000514832600019 |
url |
http://dx.doi.org/10.1016/j.gca.2020.01.035 http://hdl.handle.net/11449/197682 |
identifier_str_mv |
Geochimica Et Cosmochimica Acta. Oxford: Pergamon-elsevier Science Ltd, v. 273, p. 331-353, 2020. 0016-7037 10.1016/j.gca.2020.01.035 WOS:000514832600019 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Geochimica Et Cosmochimica Acta |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
331-353 |
dc.publisher.none.fl_str_mv |
Elsevier B.V. |
publisher.none.fl_str_mv |
Elsevier B.V. |
dc.source.none.fl_str_mv |
Web of Science 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) |
repository.mail.fl_str_mv |
|
_version_ |
1808129458124619776 |