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Siderian to Rhyacian evolution of the Juiz de Fora Complex: Arc fingerprints and correlations within the Minas-Bahia Orogen and the Western Central Africa Belt.

Authors :
Araujo, Lucas Eduardo de Abreu Barbosa
Heilbron, Monica
Teixeira, Wilson
Dussin, Ivo Antônio
de Morisson Valeriano, Claudio
Bruno, Henrique
Sato, Kei
Paravidini, Gabriel
Castro, Matheus
Source :
Precambrian Research. Jul2021, Vol. 359, pN.PAG-N.PAG. 1p.
Publication Year :
2021

Abstract

• Siderian-Rhyacian orogeny formed the Juiz de Fora Complex. • Juvenile accretion at ca. 2.44 Ga marks a primitive intra-oceanic arc setting. • Coeval TTG-Sanukitoid suites at ca. 2.20 Ga marks the mature arc setting. • ca. 2.03 Ga metamorphic zircon records the collision with the Mantiqueira Complex. The Juiz de Fora Complex (JFC) is one of the basement units of the Occidental Terrane, Central Ribeira belt, in the Neoproterozoic framework of Western Gondwana, regarded as part of the reworked border of the São Francisco Paleocontinent. The JFC comprises Paleoproterozoic granitoid rocks with TTG, calc-alkaline, sanukitoid, and tholeiite-type geochemical compositions. They exhibit complex deformational fabrics associated with two episodes of granulite-facies metamorphism, occuring in the early Orosirian and the Ediacaran. The new U-Pb (SHRIMP) isotopic ages and Lu-Hf (LA-MC-ICPMS) data combined with available lithogeochemical, whole-rock Sm-Nd and Rb-Sr isotopic data constrain the tectonic evolution of the JFC to a Siderian-Rhyacian evolved arc system. Five samples were selected for U-Pb geochronology and Lu-Hf analysis on zircon grains: a low-K tholeiite, one TTG, two sanukitoids, and a mafic tholeiite. Combined whole-rock Sm-Nd, Rb-Sr isotopes, and zircon Lu-Hf isotopic data suggest the following evolution: an initial moderately juvenile (2445 Ma) low-K tholeiitic magmatism (εNd(t) of − 0.1; εHf(t) from − 8 to + 3), followed by a moderately juvenile to evolved (2200–2182 Ma) coeval TTG-sanukitoid pulse (εNd(t) from − 0.6 to − 4.8; εHf(t) from − 11.7 to + 2.5), and eventually by a moderately juvenile (2130 Ma) tholeiitic magmatism (εNd(t) = − 0.05). The integrated information provides preliminary petrogenetic insights for these magmatic episodes, such as interaction between mantle sources and supracrustal subducted material, melting of the oceanic slab, and crustal assimilation. A ca. 2035 Ma collisional granulite event recorded in metamorphic rims and neoformed zircon grains in leucosomes, possibly marks the amalgamation of the JFC onto the Mantiqueira Complex. Geochronological and isotopic correlations with coeval terranes of the Minas-Bahia Orogen in the Brazilian and African counterparts are addressed for tectonic implications at a broader scale. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
03019268
Volume :
359
Database :
Academic Search Index
Journal :
Precambrian Research
Publication Type :
Academic Journal
Accession number :
150207796
Full Text :
https://doi.org/10.1016/j.precamres.2021.106118