Tectonically-induced strontium isotope changes in ancient restricted seas : the case of the Ediacaran-Cambrian Bambuí foreland basin system, east Brazil.

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dc.contributor.authorGuacaneme, Cristian
dc.contributor.authorBabinski, Marly
dc.contributor.authorBedoya Rueda, Carolina
dc.contributor.authorSantos, Gustavo Macedo de Paula
dc.contributor.authorCaetano Filho, Sergio
dc.contributor.authorAmaral, Matheus Henrique Kuchenbecker do
dc.contributor.authorReis, Humberto Luis Siqueira
dc.contributor.authorTrindade, Ricardo Ivan Ferreira da
dc.date.accessioned2022-09-14T19:26:42Z
dc.date.available2022-09-14T19:26:42Z
dc.date.issued2021pt_BR
dc.description.abstractThe Bambuí Group is a marine sedimentary record of an intracratonic foreland basin developed at the terminal Ediacaran and early Cambrian during the assembly of West Gondwana. Here we present a basin-scale high- resolution Sr isotope stratigraphy for the basal Bambuí Group, aiming to understand the spatial and temporal var- iations of the 87Sr/86Sr ratios and to explore the controls over the Sr isotope system in intracontinental marine environments. Assessment of the stratigraphic evolution of both Sr concentrations and Sr isotopes shows a major increase in Sr/Ca ratios (up to 0.004) and a decrease in the 87Sr/86Sr ratios from 0.7086 to 0.7076 in the high stand system tract of the basal 2nd-order sequence. These changes precede a large positive δ13C excursion typically found across the basin in the middle Bambuí Group. The high variability of both 87Sr/86Sr and Sr/Ca ra- tios was not caused by globally uniform changes in isotopic compositions of seawater, but rather likely reflect marine restriction and paleogeographic changes of the depositional environments at basin scale. This would re- sult from the tectonic uplift of Neoproterozoic orogenic belts around the São Francisco craton, which generated an isolated foreland marine basin. Compared to the global ocean, such a smaller intracontinental reservoir would be more sensitive to the Sr isotope composition from the different rock sources. We suggest that changes on the balance between carbonate production and accommodation associated with tectonically-related flexural subsi- dence progressively modified the continental drainage patterns, sedimentary sources and the chemical weathering regimes, altering the strontium influxes and isotopic compositions of the seawater in the early Bambuí basin cycle. Similar anomalies in the strontium isotope record are also recorded in coeval marine basins across West Gondwana and suggest that tectonics might have played an important role on seawater chemistry at the Neoproterozoic-Paleozoic transition.pt_BR
dc.identifier.citationGUACANEME, C. et al. Tectonically-induced strontium isotope changes in ancient restricted seas: the case of the Ediacaran-Cambrian Bambuí foreland basin system, east Brazil. Gondwana Research, v. 93, 2021. Disponível em: <https://www.sciencedirect.com/science/article/pii/S1342937X21000678>. Acesso em: 29 abr. 2022.pt_BR
dc.identifier.doihttps://doi.org/10.1016/j.gr.2021.02.007pt_BR
dc.identifier.issn1342-937X
dc.identifier.urihttp://www.repositorio.ufop.br/jspui/handle/123456789/15266
dc.identifier.uri2https://www.sciencedirect.com/science/article/pii/S1342937X21000678pt_BR
dc.language.isoen_USpt_BR
dc.rightsrestritopt_BR
dc.subjectSão Francisco Basinpt_BR
dc.titleTectonically-induced strontium isotope changes in ancient restricted seas : the case of the Ediacaran-Cambrian Bambuí foreland basin system, east Brazil.pt_BR
dc.typeArtigo publicado em periodicopt_BR
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