Paleoproterozoic crustal evolution of the northern Borborema Province, NE Brazil: Insights from high-grade metamorphic rocks of the Canindé do Ceará Complex

Amaral, Wagner da Silva; Santos, Felipe Holanda dos; Braga, Luiz Ricardo Cunha; Pitombeira, João Paulo Araújo; Sousa, Daniel Francisco Martins de; Fuck, Reinhardt A.; Dantas, Elton Luiz; Martins, Douglas Teixeira; Veríssimo, César Ulisses Vieira; Costa, Felipe Grandjean da

doi:10.1016/j.precamres.2022.106941

Cited by 2 publications

(1 citation statement)

References 118 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These Archean units of the Borborema Province generally occur in continuity with Paleoproterozoic complexes (Dantas et al 2004Souza et al 2016;Lira Santos et al 2017;Ganade et al 2017;Vale et al 2023;Costa et al 2019Costa et al , 2021Ferreira et al 2020;Brito Neves et al 2020). This association between Archean and Paleoproterozoic rocks suggests accretionary collision processes (e.g., Souza et al 2016;Neves 2015;Lira Santos et al 2015Ferreira et al 2020;Amaral et al 2023) that resulted in the formation of the basement of the Neoproterozoic sedimentary basins, which was later deformed and metamorphosed in the Brasiliano/Pan-African Orogeny (e.g., Van Schmus et al 2003;Arthaud et al 2008;Oliveira et al 2010;Brito Neves et al 2015, 2018Caxito et al 2016). This Neoproterozoic orogenic cycle was accompanied by extensive granitic magmatism that intruded all geological domains of the province (e.g., Ferreira et al 1998;Santos and Medeiros 1999;Neves et al 2000;Guimarães et al 2004), but partially preserved the Archean nuclei, where records of such intrusions are rare.…”

Section: Regional Geological Contextmentioning

confidence: 94%

Gamma-ray spectrometry, magnetic and gravity signatures of Archean nuclei of the Borborema Province, Northeastern Brazil

Oliveira,

Domingos,

Medeiros

et al. 2024

JGSB

View full text Add to dashboard Cite

Gamma-ray spectrometry, as well as magnetic and gravity data, are used to investigate the geophysical signatures of the Archean nuclei of the Borborema Province. Natural radioactivity, magnetic anomalies, and residual Bouguer gravity anomalies of the Archean nuclei exhibit distinct signatures in relation to adjacent Proterozoic domains. Gamma-ray spectrometry data reveal eTh enrichment in relation to K and eU contents in Archean units. Assuming that K and U were the dominant isotopes, this relative enrichment of eTh can be explained by the fact that Th radioisotopes have a longer half-life than the other two radionuclides and that 4.56 Ga has elapsed since Earth's formation. The intensity of the total magnetic gradient in Archean units is greater than in Proterozoic units in most nuclei. The Archean units underwent deformation and metamorphism in the Brasiliano/Pan-African Orogeny; therefore, the magnetic characteristics now observed in Archean mafic-ultramafic rocks, iron formations and gneissmigmatite complexes are the joint result of their primary properties and the superposed effects of the orogeny. All Archean nuclei of the Borborema Province show positive residual Bouguer gravity anomalies. This could be due to the conservation of the main petrophysical properties of the Archean lithosphere, and their preservation during the intense granitization that occurred in the Brasiliano/Pan-African Orogeny. As magnetic and gravity methods provide information from depth, it is possible to infer the continuity of some Archean nuclei beyond the limits established by surface geological data. Based on these results, it will be possible to use geophysical signatures to investigate the possible existence of unknown Archean units in the province.

show abstract