The Ni-Cu-PGE mineralized Brejo Seco mafic-ultramafic layered intrusion, Riacho do Pontal Orogen: Onset of Tonian (ca. 900 Ma) continental rifting in Northeast Brazil

Salgado, Silas Santos; Filho, César Fonseca Ferreira; Caxito, Fabrício de Andrade; Uhlein, Alexandre; Dantas, Elton Luiz; Stevenson, Ross

doi:10.1016/j.jsames.2016.06.001

Cited by 42 publications

(36 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These values indicate roughly the same spectra of source areas for both units. A shift can be observed from the bottom units from the Vazante Group (Serra do Garrote, Morro do Calcário and Serra do Poço Verde formations), with high negative εNd (900) of about -10.0, increasing to -5.0 in the Serra da Lapa Formation. Calculated εNd (900) for the Canastra Group is concordant to the upper units of the Vazante Group (Serra da Lapa Formation).…”

Section: Resultsmentioning

confidence: 93%

“…A shift can be observed from the bottom units from the Vazante Group (Serra do Garrote, Morro do Calcário and Serra do Poço Verde formations), with high negative εNd (900) of about -10.0, increasing to -5.0 in the Serra da Lapa Formation. Calculated εNd (900) for the Canastra Group is concordant to the upper units of the Vazante Group (Serra da Lapa Formation). The range of calculated initial 87 Sr/ 86 Sr ratios (900 Ma) is also similar for both Canastra and Vazante groups, i.e., from 0.740703 to 0.975134 and from 0.737624 to 0.915732, respectively (Fig.…”

Section: Resultsmentioning

confidence: 93%

“…Ranges of εNd (900) values and ratios of 147 Sm/ 144 Nd also express this upward shift. Units of the inferior portion of the Vazante group column show more negative εNd (900) ranges than the upper Serra da Lapa Formation and rocks from the Canastra Group. Results for the Serra do Garrote vary from -8 to -13, and between -10 to -12 for the Morro do Calcário and Serra do Poço Verde formations.…”

Section: Discussionmentioning

confidence: 89%

“…Calculated isotope ratios for 0.90 Ga result in much narrower ranges of εNd (900) for the Vazante and Canastra groups, from -4.8 to -14.3 and from -4.8 to -16.0, respectively (Fig. 3).…”

Section: Resultsmentioning

confidence: 97%

See 3 more Smart Citations

The Vazante and Canastra groups revisited: Sm-Nd and Sr isotopes - evidence for contribution from Tonian intraplate magmatism during passive margin development along the SW São Francisco margin, Brazil

et al. 2019

View full text Add to dashboard Cite

Combined Sm-Nd isotope studies and U-Pb ages of detrital zircons have shown significant differences between the provenance patterns of Neoproterozoic metasedimentary successions in the Southern Brasília belt. The Vazante and Canastra groups are passive margin deposits with source areas in the Archean/Paleoproterozoic São Francisco Craton basement and Mesoproterozoic cover units. In literature, the younging trend of Nd model ages observed in the Vazante Group is interpreted as resulting from the contribution of the Neoproterozoic Goiás Magmatic Arc. Also, detrital zircons younger than 0.90 Ga were not recorded in the Vazante or Canastra groups, which zircon populations are older than 0.93 Ga. This work presents new Sm-Nd and Sr isotope data of metasedimentary rocks from the Vazante and Canastra groups, collected in a 400 km2 area in northwest Minas Gerais, Brazil. The improved database of previously published and new data corroborates with the younging pattern of TDM along the Vazante Group. Isochronic diagrams show that samples from Vazante and Canastra groups scatter along mixing lines between the fields defined by the older cratonic rocks and the more juvenile ones. Here we present the Tonian Intraplate Magmatism within the São Francisco Craton as the juvenile source.

show abstract

Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 89%

“…Calculated isotope ratios for 0.90 Ga result in much narrower ranges of εNd (900) for the Vazante and Canastra groups, from -4.8 to -14.3 and from -4.8 to -16.0, respectively (Fig. 3).…”

Section: Resultsmentioning

confidence: 97%

See 2 more Smart Citations

The Vazante and Canastra groups revisited: Sm-Nd and Sr isotopes - evidence for contribution from Tonian intraplate magmatism during passive margin development along the SW São Francisco margin, Brazil

et al. 2019

View full text Add to dashboard Cite

show abstract

“…This sequence is intruded by the Brejo Seco Complex, a mafic-ultramafic intrusion that bears Ni-Cu-PGE deposits crystallized at ca. 900 Ma (Sm-Nd whole-rock isochron; Salgado et al 2016). The Brejo Seco Complex is interpreted as intruded in a continental extension setting related to the emplacement of a mantle plume (Salgado et al 2016).…”

Section: Geological Contextmentioning

confidence: 99%

New U-Pb (SHRIMP) and first Hf isotope constraints on the Tonian (1000-920 Ma) Cariris Velhos event, Borborema Province, NE Brazil

et al. 2020

Self Cite

View full text Add to dashboard Cite

Orthogneisses associated with metavolcanosedimentary successions related to the 1000-920 Ma Cariris Velhos event occur mainly in a ca. 700 km-long sigmoidal-shaped belt that crosscuts the Transversal Zone of the Borborema Province and extends to the fold belts located in its southern or external zone (part of the Riacho do Pontal and Sergipano orogens). Despite its importance, the tectonic setting and the role of those rocks in the geological evolution of the Borborema Province are contentious and not yet well understood. New zircon U-Pb SHRIMP data on an augen-gneiss sill of the Afeição Suite intruding mica-schists mapped as part of the Santa Filomena Complex yielded a Concordia Age of 974 ± 11 Ma, indicating that at least part of the metasedimentary rocks in the internal zone of the Riacho do Pontal Orogen are Tonian or older and possibly related to the Cariris Velhos event. Hf-in-zircon isotope data are presented for the first time for Cariris Velhos-related ortho-derived rocks of the Afeição Suite. Analyzed samples yielded εHf(t) in a narrow range between-1.51 and +2.41, with associated T DMHf of 1.6-1.4 Ga, similar to previously obtained Nd isotope data with εNd(t) =-1.0 to +3.1 and T DMNd of 1.5-1.2 Ga. A possible scenario to explain both the geochemical features and the moderately juvenile to slightly evolved, near-chondritic Hf and Nd isotope signatures is a continental arc setting, where fractionated melts produced in the supra-subduction zone mantle wedge carrying a Tonian juvenile signature became contaminated with discrete amounts of Archean-Paleoproterozoic continental crust during ascent, producing Mesoproterozoic model ages which represent the mixture of those two end-members.

show abstract

The Rio Preto and Riacho do Pontal Belts

Caxito

Uhlein

Dantas

et al. 2016

São Francisco Craton, Eastern Brazil

View full text Add to dashboard Cite

The Ni-Cu-PGE mineralized Brejo Seco mafic-ultramafic layered intrusion, Riacho do Pontal Orogen: Onset of Tonian (ca. 900 Ma) continental rifting in Northeast Brazil

Cited by 42 publications

References 37 publications

The Vazante and Canastra groups revisited: Sm-Nd and Sr isotopes - evidence for contribution from Tonian intraplate magmatism during passive margin development along the SW São Francisco margin, Brazil

The Vazante and Canastra groups revisited: Sm-Nd and Sr isotopes - evidence for contribution from Tonian intraplate magmatism during passive margin development along the SW São Francisco margin, Brazil

New U-Pb (SHRIMP) and first Hf isotope constraints on the Tonian (1000-920 Ma) Cariris Velhos event, Borborema Province, NE Brazil

The Rio Preto and Riacho do Pontal Belts

Contact Info

Product

Resources

About