Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil
Autor(a) principal: | |
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Data de Publicação: | 2001 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFBA |
Texto Completo: | http://repositorio.ufba.br/ri/handle/ri/18090 |
Resumo: | Texto completo: acesso restrito. p. 303–329 |
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Misi, AroldoSanches, Andreia LimaAzmy, KaremVeizer, JanDardenne, Marcel Auguste2015-10-09T18:46:34Z20010301-9268http://repositorio.ufba.br/ri/handle/ri/18090v. 112, n. 3-4Texto completo: acesso restrito. p. 303–329The Vazante Formation consists of approximately 1700 m of mainly microbial mats and stromatolitic reefal lenses that were deposited on shallow marine platform and have been entirely dolomitized. Samples representing different dolomite generations were taken from three boreholes covering the entire spectrum of the Vazante carbonates. Dolomites can be classified, based on petrography and geochemistry, into four generations ranging in crystal size between ∼4 μm (almost micritic) and 3 mm and occurring as both replacements and cements. The Sr/Ca molar ratios, calculated for the dolomitizing fluid (0.0006–0.0138), suggest a contribution from a non-marine, possibly meteoric, water component. The δ18O and δ13C values vary from −0.1 to −14.3‰ (PDB) and 0.2 to −2.3‰ (PDB), respectively. Fluid-inclusion study suggests that dolomitization must have commenced at a temperature lower than about 50 °C. A mixing-zone model of dolomitization for Dolomites I–III satisfies the constraints from elemental chemistry, δ18O, 87Sr/86Sr and fluid inclusions. The petrographic and chemical criteria of the latest generation, Dolomite IV, reflect conditions of deep burial environment at temperatures above 120–130 °C. The δ13C values show only small variations at the base of the formation, followed by a major negative plunge (∼4‰) at the top, this plunge correlated with the Sturtian glacial phase. In contrast to C-isotopes, only few samples may have retained their near-primary 87Sr/86Sr values of 0.70614–0.70734. The lowest 87Sr/86Sr value (0.70614), from fibrous cement in the upper part of the formation, correlates with the negative δ13C shift and is also consistent with the Sr-isotope signature proposed for the glacial Sturtian seawater. The δ34S values, obtained from sulfates trapped in carbonates, range between 10.8 and 16.9‰ with a jump to 21.3‰ in the overlying formation. All isotope signals are within the range suggested for the early Neoproterozoic seawater, but the Precambrian baseline is poorly known and additional work is required to confirm this tentative assignment.Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-02-05T14:23:11Z No. of bitstreams: 1 Aroldo Misi.pdf: 1475684 bytes, checksum: 2cf690d3f8ad6bc11020176429d6cd67 (MD5)Approved for entry into archive by Rodrigo Meirelles (rodrigomei@ufba.br) on 2015-10-09T18:46:34Z (GMT) No. of bitstreams: 1 Aroldo Misi.pdf: 1475684 bytes, checksum: 2cf690d3f8ad6bc11020176429d6cd67 (MD5)Made available in DSpace on 2015-10-09T18:46:34Z (GMT). No. of bitstreams: 1 Aroldo Misi.pdf: 1475684 bytes, checksum: 2cf690d3f8ad6bc11020176429d6cd67 (MD5) Previous issue date: 2001http://dx.doi.org/10.1016/S0301-9268(01)00194-2reponame:Repositório Institucional da UFBAinstname:Universidade Federal da Bahia (UFBA)instacron:UFBAProterozoic carbonatesDolomitesGeochemistryIsotope stratigraphyVazante FormationBrazilDolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, BrazilPrecambrian Researchinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article10000-01-01Brasilinfo:eu-repo/semantics/openAccessengORIGINALAroldo Misi.pdfAroldo Misi.pdfapplication/pdf1475684https://repositorio.ufba.br/bitstream/ri/18090/1/Aroldo%20Misi.pdf2cf690d3f8ad6bc11020176429d6cd67MD51LICENSElicense.txtlicense.txttext/plain1345https://repositorio.ufba.br/bitstream/ri/18090/2/license.txtff6eaa8b858ea317fded99f125f5fcd0MD52TEXTAroldo Misi.pdf.txtAroldo Misi.pdf.txtExtracted texttext/plain76447https://repositorio.ufba.br/bitstream/ri/18090/3/Aroldo%20Misi.pdf.txt34fbbbda43d678a0f0c287e84666abfaMD53ri/180902022-03-23 20:24:03.536oai:repositorio.ufba.br:ri/18090VGVybW8gZGUgTGljZW7vv71hLCBu77+9byBleGNsdXNpdm8sIHBhcmEgbyBkZXDvv71zaXRvIG5vIFJlcG9zaXTvv71yaW8gSW5zdGl0dWNpb25hbCBkYSBVRkJBLgoKIFBlbG8gcHJvY2Vzc28gZGUgc3VibWlzc++/vW8gZGUgZG9jdW1lbnRvcywgbyBhdXRvciBvdSBzZXUgcmVwcmVzZW50YW50ZSBsZWdhbCwgYW8gYWNlaXRhciAKZXNzZSB0ZXJtbyBkZSBsaWNlbu+/vWEsIGNvbmNlZGUgYW8gUmVwb3NpdO+/vXJpbyBJbnN0aXR1Y2lvbmFsIGRhIFVuaXZlcnNpZGFkZSBGZWRlcmFsIGRhIEJhaGlhIApvIGRpcmVpdG8gZGUgbWFudGVyIHVtYSBj77+9cGlhIGVtIHNldSByZXBvc2l077+9cmlvIGNvbSBhIGZpbmFsaWRhZGUsIHByaW1laXJhLCBkZSBwcmVzZXJ2Ye+/ve+/vW8uIApFc3NlcyB0ZXJtb3MsIG7vv71vIGV4Y2x1c2l2b3MsIG1hbnTvv71tIG9zIGRpcmVpdG9zIGRlIGF1dG9yL2NvcHlyaWdodCwgbWFzIGVudGVuZGUgbyBkb2N1bWVudG8gCmNvbW8gcGFydGUgZG8gYWNlcnZvIGludGVsZWN0dWFsIGRlc3NhIFVuaXZlcnNpZGFkZS4KCiBQYXJhIG9zIGRvY3VtZW50b3MgcHVibGljYWRvcyBjb20gcmVwYXNzZSBkZSBkaXJlaXRvcyBkZSBkaXN0cmlidWnvv73vv71vLCBlc3NlIHRlcm1vIGRlIGxpY2Vu77+9YSAKZW50ZW5kZSBxdWU6CgogTWFudGVuZG8gb3MgZGlyZWl0b3MgYXV0b3JhaXMsIHJlcGFzc2Fkb3MgYSB0ZXJjZWlyb3MsIGVtIGNhc28gZGUgcHVibGljYe+/ve+/vWVzLCBvIHJlcG9zaXTvv71yaW8KcG9kZSByZXN0cmluZ2lyIG8gYWNlc3NvIGFvIHRleHRvIGludGVncmFsLCBtYXMgbGliZXJhIGFzIGluZm9ybWHvv73vv71lcyBzb2JyZSBvIGRvY3VtZW50bwooTWV0YWRhZG9zIGVzY3JpdGl2b3MpLgoKIERlc3RhIGZvcm1hLCBhdGVuZGVuZG8gYW9zIGFuc2Vpb3MgZGVzc2EgdW5pdmVyc2lkYWRlIGVtIG1hbnRlciBzdWEgcHJvZHXvv73vv71vIGNpZW5077+9ZmljYSBjb20gCmFzIHJlc3Ryae+/ve+/vWVzIGltcG9zdGFzIHBlbG9zIGVkaXRvcmVzIGRlIHBlcmnvv71kaWNvcy4KCiBQYXJhIGFzIHB1YmxpY2Hvv73vv71lcyBzZW0gaW5pY2lhdGl2YXMgcXVlIHNlZ3VlbSBhIHBvbO+/vXRpY2EgZGUgQWNlc3NvIEFiZXJ0bywgb3MgZGVw77+9c2l0b3MgCmNvbXB1bHPvv71yaW9zIG5lc3NlIHJlcG9zaXTvv71yaW8gbWFudO+/vW0gb3MgZGlyZWl0b3MgYXV0b3JhaXMsIG1hcyBtYW5077+9bSBhY2Vzc28gaXJyZXN0cml0byAKYW8gbWV0YWRhZG9zIGUgdGV4dG8gY29tcGxldG8uIEFzc2ltLCBhIGFjZWl0Ye+/ve+/vW8gZGVzc2UgdGVybW8gbu+/vW8gbmVjZXNzaXRhIGRlIGNvbnNlbnRpbWVudG8KIHBvciBwYXJ0ZSBkZSBhdXRvcmVzL2RldGVudG9yZXMgZG9zIGRpcmVpdG9zLCBwb3IgZXN0YXJlbSBlbSBpbmljaWF0aXZhcyBkZSBhY2Vzc28gYWJlcnRvLgo=Repositório InstitucionalPUBhttp://192.188.11.11:8080/oai/requestopendoar:19322022-03-23T23:24:03Repositório Institucional da UFBA - Universidade Federal da Bahia (UFBA)false |
dc.title.pt_BR.fl_str_mv |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
dc.title.alternative.pt_BR.fl_str_mv |
Precambrian Research |
title |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
spellingShingle |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil Misi, Aroldo Proterozoic carbonates Dolomites Geochemistry Isotope stratigraphy Vazante Formation Brazil |
title_short |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
title_full |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
title_fullStr |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
title_full_unstemmed |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
title_sort |
Dolomitization and isotope stratigraphy of the Vazante Formation, São Francisco Basin, Brazil |
author |
Misi, Aroldo |
author_facet |
Misi, Aroldo Sanches, Andreia Lima Azmy, Karem Veizer, Jan Dardenne, Marcel Auguste |
author_role |
author |
author2 |
Sanches, Andreia Lima Azmy, Karem Veizer, Jan Dardenne, Marcel Auguste |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Misi, Aroldo Sanches, Andreia Lima Azmy, Karem Veizer, Jan Dardenne, Marcel Auguste |
dc.subject.por.fl_str_mv |
Proterozoic carbonates Dolomites Geochemistry Isotope stratigraphy Vazante Formation Brazil |
topic |
Proterozoic carbonates Dolomites Geochemistry Isotope stratigraphy Vazante Formation Brazil |
description |
Texto completo: acesso restrito. p. 303–329 |
publishDate |
2001 |
dc.date.issued.fl_str_mv |
2001 |
dc.date.accessioned.fl_str_mv |
2015-10-09T18:46:34Z |
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://repositorio.ufba.br/ri/handle/ri/18090 |
dc.identifier.issn.none.fl_str_mv |
0301-9268 |
dc.identifier.number.pt_BR.fl_str_mv |
v. 112, n. 3-4 |
identifier_str_mv |
0301-9268 v. 112, n. 3-4 |
url |
http://repositorio.ufba.br/ri/handle/ri/18090 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
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openAccess |
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Brasil |
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http://dx.doi.org/10.1016/S0301-9268(01)00194-2 |
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reponame:Repositório Institucional da UFBA instname:Universidade Federal da Bahia (UFBA) instacron:UFBA |
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Universidade Federal da Bahia (UFBA) |
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