Combined use of Sm–Nd isotopes and lithogeochemistry in the sedimentary provenance of the southern Ediacaran-Cambrian Bambuí foreland basin system, Brazil.

Simple item page
dc.contributor.authorParavidini, Gabriel
dc.contributor.authorReis, Humberto Luis Siqueira
dc.contributor.authorHeilbron, Monica da Costa Pereira Lavalle
dc.contributor.authorCarvalho, Manuela de Oliveira
dc.contributor.authorAguiar Neto, Carla Cristine
dc.contributor.authorValeriano, Claudio de Morisson
dc.date.accessioned2022-09-14T19:19:31Z
dc.date.available2022-09-14T19:19:31Z
dc.date.issued2021pt_BR
dc.description.abstractSedimentary provenance analysis based on lithogeochemistry and isotope data has been extensively applied in the investigation of ancient sedimentary successions. This approach contributes to understand the tectonic setting in which these strata were deposited and to recognize major provenance patterns in time and space. The Ediacaran to Cambrian Bambuí Group is exposed in the Sao ̃ Francisco craton (SE Brazil) and represents the sedimentary record of a foreland basin system developed during the assembly of the West Gondwana. Different lines of evidence indicate that this basin system evolved into a confined setting, due to the overloads imposed on the western and eastern margins of the Sao ̃ Francisco paleoplate by the diachronic Brasília and Araçuaí orogenic systems, respectively. New whole-rock lithogeochemistry and Sm–Nd isotopic data were applied to evaluate the overall sedimentary provenance patterns of the Bambuí strata exposed in the southern portion of the Sao ̃ Francisco craton (i.e., within the Sete Lagoas basement high) and to identify its possible sources. Coupled (La/Yb)n and Th/Sc ratios with 147Sm/144Nd and εNd isotopes allowed the recognition of three contrasting source patterns associated with different 2nd order sequences. The lower sequence comprises carbonate ramp deposits and shows highly heterogeneous and more negative εNd ranging from − 10.5 to − 4.5, as well as Th/Sc and (La/Yb)n ratios between 0.6 and 0.7 and 0.54 and 0.76, respectively. The provenance patterns point toward intermediate-dominated and isotopically evolved crustal sources, with mean TDM model ages between 1.5 and 2.0 Ga. The overlying 2nd-order sequence is composed of fine-to medium-grained siliciclastics grading upward into platformal oolitic calcarenites and calcilutites. This succession exhibits homo- geneous and less negative εNd(t) values between − 6.8 and − 5.2, with low Th/Sc (0.6–0.8) and (La/Yb)n (0.60–0.84) ratios. The uppermost Bambuí 2nd-order sequence, marked by greenish siltstones and arkoses grading upward into storm-bedded arkoses and lithic sandstones, shows homogeneous εNd(t) ranging from − 8.5 to − 6.1, slightly more negative than the underlying successions, and relatively higher Th/Sc and (La/Yb)n ratios ranging from 0.7 to 1.3 and 0.85 to 1.28, respectively. The Sm–Nd isotopic signature of the upper deposits indicates felsic-dominated and more isotopically juvenile crustal sources with TDM model ages of 1.5–1.7 Ga, characteristics compatible with Ediacaran arc-related rocks and post-tectonic granites exposed in the Araçuaí orogen. Our data indicate that the Proterozoic cratonic covers, their correlatives in the surrounding orogens, and magmatic rocks from the Araçuaí orogen acted as major sedimentary sources during the first evolutionary stages of the Bambuí basin-cycle in the Sete Lagoas basement high, which behaved as a forebulge depocenter. During the deposition of the overlying sequences, the Araçuaí orogen rocks became increasingly important in sourcing the Ediacaran- Cambrian foreland system in this depocenter. Besides revealing the major provenance patterns through the evolution of an ancient and partially confined foreland basin system, our data also demonstrates that even minor changes in the Sm–Nd system might be useful as reliable elements on the provenance analysis of sedimentary systems elsewhere.pt_BR
dc.identifier.citationPARAVIDINI, G. et al. Combined use of Sm–Nd isotopes and lithogeochemistry in the sedimentary provenance of the southern Ediacaran-Cambrian Bambuí foreland basin system, Brazil. Journal of South American Earth Sciences, v. 111, 2021. Disponível em: <https://www.sciencedirect.com/science/article/pii/S0895981121002765>. Acesso em: 29 abr. 2022.pt_BR
dc.identifier.doihttps://doi.org/10.1016/j.jsames.2021.103429pt_BR
dc.identifier.issn0895-9811
dc.identifier.urihttp://www.repositorio.ufop.br/jspui/handle/123456789/15264
dc.identifier.uri2https://www.sciencedirect.com/science/article/pii/S0895981121002765pt_BR
dc.language.isoen_USpt_BR
dc.rightsrestritopt_BR
dc.subjectSm–Nd systematicspt_BR
dc.subjectWest – Gondwanapt_BR
dc.subjectBambuí grouppt_BR
dc.titleCombined use of Sm–Nd isotopes and lithogeochemistry in the sedimentary provenance of the southern Ediacaran-Cambrian Bambuí foreland basin system, Brazil.pt_BR
dc.typeArtigo publicado em periodicopt_BR
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
ARTIGO_CombinedUseSm.pdf
Size:
9.05 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
DEGEO - Artigos publicados em periódicos