Peritidal microbialites in the upper Araras Group : Morphotypes, potential preservation and the relation with the Ediacaran-Cambrian unconformity in the Araras-Alto Paraguai Basin, southern Amazon Craton.

dc.contributor.authorRomero, Guilherme Raffaeli
dc.contributor.authorSantos, Renan Fernandes dos
dc.contributor.authorNogueira, Afonso César Rodrigues
dc.contributor.authorRudnitzki, Isaac Daniel
dc.contributor.authorFairchild, Thomas Rich
dc.date.accessioned2023-08-22T18:11:37Z
dc.date.available2023-08-22T18:11:37Z
dc.date.issued2022pt_BR
dc.description.abstractThe Proterozoic biosphere was dominated by shallow-marine and intertidal bacterial biota, as evident from a robust record of microbialites in carbonate rocks. The lower Ediacaran successions in the southeastern Amazon Craton, Brazil represented by carbonates rocks of the Araras Group, record excellent occurrences of microbialites implying significant evidence for shallow marine colonization post-Snowball Earth Events (∼635 Ma). Microbialites occur at the lower and upper units of this group -Mirassol D'Oeste and Nobres, respectively with the lower associated to the Marinoan glaciation event. The upper unit, Nobres Formation, is here described with outcrop-based facies analysis discontinuously exposed in the Araras-Alto Paraguai basin. This allowed the paleoenvironmental reconstructions of the carbonate peritidal settings, organized in tidal flats and sabkha meter-scale cycles. Fifteen levels of microbialites have been described, with 4 morphotype associations. These microbialites colonized upper tidal flat zones forming stromatolite deposits of bulbous domes, stratiform, pseudo-columnar, and “cerebroid” forms. The recurrent cyclicity indicates a residence time of hydrodynamic and climatic variations for a long time producing minimum morphological changes without any decline evidence. In addition, no metazoan competition was observed in these strata. The siliciclastic inflow observed in the top of Nobres Formation is interpreted as seasonal variations that imprint turbidity in the shallow waters causing a diversification of the morphology of microbialites. The microbialite record in the Nobres Formation do not show any evolutionary trend or apparent decline, that has been attributed to the evolution of substrate-modifying metazoans, but suggest a continuous record truncated by the Ediacaran-Cambrian unconformity found at the upper portion of the Araras Group.pt_BR
dc.identifier.citationROMERO, G. R. et al. Peritidal microbialites in the upper Araras Group : Morphotypes, potential preservation and the relation with the Ediacaran-Cambrian unconformity in the Araras-Alto Paraguai Basin, southern Amazon Craton. Journal of South American Earth Sciences, v. 120, artigo e104085, dez. 2022. Disponível em: <https://www.sciencedirect.com/science/article/pii/S0895981122003716>. Acesso em: 15 mar. 2023.pt_BR
dc.identifier.doihttps://doi.org/10.1016/j.jsames.2022.104085pt_BR
dc.identifier.issn1873-0647
dc.identifier.urihttp://www.repositorio.ufop.br/jspui/handle/123456789/17330
dc.identifier.uri2www.sciencedirect.com/science/article/pii/S0895981122003716pt_BR
dc.language.isoen_USpt_BR
dc.rightsrestritopt_BR
dc.subjectMicrobialitespt_BR
dc.subjectNeoproterozoicpt_BR
dc.subjectAraras-Alto Paraguai basinpt_BR
dc.subjectCarbonate inner platformpt_BR
dc.subjectNobres formationpt_BR
dc.titlePeritidal microbialites in the upper Araras Group : Morphotypes, potential preservation and the relation with the Ediacaran-Cambrian unconformity in the Araras-Alto Paraguai Basin, southern Amazon Craton.pt_BR
dc.typeArtigo publicado em periodicopt_BR
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