40Ar/39Ar geochronology of gold mineralization in Brasiliano strike-slip shear zones in the Borborema province, NE Brazil

Araújo, Maria Rizoneide Negreiros de; Vasconcelos, Paulo; Silva, Fernando C. Alves Da; Sá, Emanuel Ferraz Jardim de; Sá, Jaziel Martins

doi:10.1016/j.jsames.2005.06.009

Cited by 35 publications

(18 citation statements)

References 28 publications

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“…In contrast, Ebert (1970) argued in favor of a palingenteic origin of the BPP pegmatitesbecause of the lack of a clear fi eld relation with a particular granite type or intrusion. Pegmatite ages using U/Pb isotopes in columbite group minerals, 40/39 Ar in biotites, and in a Sm/Nd in whole rock/garnet/K-feldspar isochron range respectively between 509± to 515± Ma, 523±2.5Ma and 494±15Ma respectively (Baumgartner et al 2006, Araújo et al 2005 and this contribution).…”

Section: Granitic Sourcementioning

confidence: 86%

The Borborema pegmatite Province, NE-Brazil revisited

Beurlen¹,

Barreto²,

Martin³

et al. 2024

Est. Geol.

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Section: Granitic Sourcementioning

confidence: 86%

The Borborema pegmatite Province, NE-Brazil revisited

Beurlen¹,

Barreto²,

Martin³

et al. 2024

Est. Geol.

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“…The Ar-Ar biotite ages (Araújo et al 2005) and U-Pb columbite ages (Baumgartner et al 2006), more recently obtained on pegmatites with low degree of fractionation and weak internal zoning, are 525 and 509-515 Ma, respectively. All these geochronological data of pegmatites are much younger than the 570-Ma (or older) ages, so far obtained for some of the main, larger, G3 and G4 granite intrusions Fig.…”

Section: Geologymentioning

confidence: 94%

Nb–Ta–(Ti–Sn) oxide mineral chemistry as tracer of rare-element granitic pegmatite fractionation in the Borborema Province, Northeastern Brazil

et al. 2007

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The Borborema Pegmatitic Province (BPP), northeastern Brazil, is historically important for tantalum mining and also famous for top-quality specimens of exotic Nb-Ta oxides and, more recently, for the production of gem quality, turquoise blue, 'Paraíba Elbaite.' With more than 750 registered mineralized rare-element granitic pegmatites, the BPP extends over an area of about 75 by 150 km in the eastern part of the Neoproterozoic Seridó Belt. The Late Cambrian pegmatites are mostly hosted by a sequence of Neoproterozoic cordierite-sillimanite biotite schists of the Seridó Formation and quartzites and metaconglomerates of the Equador Formation. The trace-element ratios in feldspar and micas allow to classify most pegmatites as belonging to the beryl-columbite phosphate subtype. Electron microprobe analyses (EMPA) of columbite, tapiolite, niobiantantalian rutile, ixiolite and wodginite group minerals from 28 pegmatites in the BPP are used to evaluate the effectiveness of Nb-Ta oxide chemistry as a possible exploration tool, to trace the degree of pegmatite fractionation and to classify the pegmatites. The columbite group mineral composition allows to establish a compositional trend from manganoan ferrocolumbite to manganocolumbite and on to manganotantalite. This trend is typical of complex spodumene-and/or lepidolite-subtype pegmatites. It clearly contrasts with another trend, from ferrocolumbite through ferrotantalite to ferrowodginite and ferrotapiolite compositions, typical of pegmatites of the beryl-columbite phosphate subtype. Large scatter and anomalous trends in zoned crystals partially overlap and conceal the two main evolution patterns. This indicates that a large representative data set of heavy mineral concentrate samples, collected systematically along cross-sections, would be necessary to predict the metallogenetic potential of individual pegmatites. Other mineral species, e.g. garnets and/or tourmaline, with a more regular distribution than Nb-Ta oxides, would be more appropriate and less expensive for routine exploration purposes. The currently available Nb-Ta oxide chemistry data suggest the potential for highly fractionated Ta-Li-Cs pegmatites in the BPP, so far undiscovered, and encourages further, more detailed research.

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“…The columbotantalite grains yielded U-Pb ages between 514.9 ± 1.1 and 509.5 ± 2.9 Ma, which represents the minimum age for the Brasiliano orogeny in the Seridó Belt (Baumgartner et al, 2006). Argon-argon isotope data from mica samples from the Seridó Belt indicate a stage of late-orogenic cooling between 500 and 480 Ma (Cunha de Souza, 1996;Corsini et al, 1998;Araújo et al, 2005;Hollanda et al, 2010).…”

Section: Geologic Settingmentioning

confidence: 99%