O Terreno Tectonoestratigráfico São Pedro: Oeste da Zona Transversal – Província Borborema

Neves, Benjamim Bley de Brito; Dantas, Elton Luiz; Santos, Ticiano José Saraiva dos

doi:10.11606/issn.2316-9095.v22-197489

Cited by 2 publications

(5 citation statements)

References 13 publications

(20 reference statements)

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“…This typology characterizes granitic rocks that occur in post-collisional settings, corroborating a younger Neoarchean event. This information adds to the U-Pb geochronology data in the 2.6 to 2.5 Ga interval already available in the literature (Silva 1997;Martins 2017;Pitarello et al 2019;Gomes et al 2021;Brito Neves et al 2022). The representativeness of these data shows that crustal growth during the Neoarchean was notable, mainly characterized by the intrusion of type A 2 rocks in the lithotypes of the Granjeiro Complex.…”

Section: Neoarchean Crustal Growthsupporting

confidence: 53%

“…48 Ga,, indicating sources in the interval between the Paleoproterozoic and Paleoarchean for these units. The U-Pb Ages obtained for different orthogneisses comprised an age range between 3.5 and 2.3 Ga. Based on this information, Brito Neves et al (2022) suggest that the region in which the Granjeiro Complex is located, called São Pedro Terrain in this study, may represent an extension of the Gavião Block, the northern portion of the São Francisco Cráton.…”

Section: Granjeiro Complexmentioning

confidence: 61%

“…The ages of the intervals attributed to metamafic and metaultramafic rocks in the literature correspond to two distinct intervals: 3.0 Ga (Freimann 2014) and 2.8 to 2.6 Ga (Bautista 2012;Ancelmi 2016;Pitarello et al 2019;Brito Neves et al 2022). Freimann's (2014) geochronological information for hornblendite was excluded from the regional analysis due to high uncertainty, due to the high MSWD associated with it.…”

Section: Tectono-magmatic Characterization Of the Granjeiro Complexmentioning

confidence: 92%

“…In the southwestern portion of the Granjeiro Complex, the work of Martins (2017), Pitarello et al (2019) and Brito Neves et al (2022). The first author reported dates on tonalitic and syenogranitic orthogneisses, obtaining ages of 3.42 and 2.66 Ga, respectively.…”

Section: Granjeiro Complexmentioning

confidence: 99%

“…The mineralogical and geochemical patterns observed suggest a subdivision into three distinct groups: deposition of chemical sediments from seawater in regions further away from the continent, with a low influx of terrigenous sediments; deposition close to the continent; and chemical sediments precipitated from seawater with postdepositional or hydrothermal alteration processes. Brito Neves et al (2022) carried out a series of geochronological dates using the Sm-Nd and U-Pb method on the lyotypes that make up the complex. The results revealed TDM values varying between 2.29 and 3.…”

Section: Granjeiro Complexmentioning

confidence: 99%

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Lithogeochemistry and zircon U-Pb geochronology of the Granjeiro Complex and associated units, Curral Novo do Piauí, NW-Borborema Province, Brazil: implications for Archean to Paleoproterozoic crustal evolution

Vale,

Monteiro,

Basto

et al. 2023

JGSB

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The Curral Novo Iron District, located in the center-east of the state of Piauí, is hosted in the Granjeiro Complex in its southwestern section, located in the Rio Piranhas-Seridó Domain, northern subprovince of Borborema Province. In this district, the banded iron rocks have an average content of approximately 27% Fe, with an estimated potential of more than one million tons of ore. Through the integration of petrographic, isotopic, geochemical and geochronological field data, a comprehensive characterization of the lithotypes present in the complex (orthogneisses, migmatites and a metavolcano-sedimentary unit) and associated units (syenogranitic orthogneisses and pegmatite granites) was carried out, focusing on the evolutionary discussion of this Archean complex, as well as the origin of metasomatism present in the iron district. Tonalitic and granodioritic orthogneisses include calcic to alkali-calcic rocks with low mafic mineral content. These rocks have low concentrations of lithophile elements and high field potential elements, significant fractionation of light rare earth elements and slightly negative Eu anomalies. U-Pb geochronology in tonalitic orthogneiss zircon from the Granjeiro Complex indicates the age of the protolith in the Paleoarchean at 3349 Ma. The metavolcano-sedimentary unit is made up of amphibolites, magnesian schists, serpentinites and banded iron rocks. Such rocks derived from mafic and ultramafic protoliths have a komatiitic and basaltic composition and have a genesis associated with the subduction phase of oceanic plates, presenting a geochemical affinity similar to that of modern island arc rocks. The iron rocks present sedimentary facies of the oxide and silicate types, with strong impoverishment of high field potential elements and rare earth elements and negative Ce anomalies. These units are intruded by syenogranitic plutons, collisional powders, type A2, aged 2651 Ma. Chemically, these granites are metaluminous to peraluminous, alkali-calcic and ferrous types, having a slight enrichment of light rare earth elements in relation to heavy rare earth elements and high contents of lithophile elements and high field potential elements. The rocks of the Granjeiro Complex show records of strong crustal reworking in the Paleoproterozoic, starting from the Riacian, with a metamorphic peak in metavolcanosedimentary rocks indicated by U-Pb dating in amphibolite zircon at 2200 Ma. An important magmatic event related to the global process of extension of continental masses during the Statherian period, aged 1759 Ma, represented by several intrusive plutons in all units of the area, promoted hydrothermal alteration in the surrounding amphibolites and iron rocks, causing silicification, albitization, potassification, carbonatization, sulfidation and reconcentration of iron. δ 34 S values = -3.11 to +2.3 per mil in hydrothermal sulfides suggest magmatic sources for the sulfur associated with the hydrothermal system. The incorporation of the analysis of these diverse geological data, made it poss...

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Section: Neoarchean Crustal Growthsupporting

confidence: 53%

Section: Granjeiro Complexmentioning

confidence: 61%