The role of Ediacaran synkinematic anatectic rocks and the late-orogenic charnockitic rocks in the development of the hot Araçuaí belt
Date
10/2021Author
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Abstract
The orogenic evolution of the hot Araçuaí belt is characterized by continuous magmatic activity, with magmas of different compositions recording a long-lived (∼630 to ∼530 Ma) tectono-thermal evolution in response to convergence between the Congo and São Francisco continents during the West Gondwana amalgamation. Geochemical data from the Carlos Chagas domain (CCD) and the Nova Venécia Complex (NVC), in the hinterland of this belt, show that these rocks contain high amounts of heat producing elements – HPEs – (Th, U, and K) and have a dominant peraluminous signature, suggesting that they result from partial melting of continental crust. The CCD is intruded by post-collisional charnockites that have a dominant shoshonitic signature, interpreted as representing magmas from an enriched mantle reservoir with a variable amount of crustal contamination. Detailed morphological investigations at the macro- and micro-scales show that the CCD contains remnants of residuum material from metamorphic reactions associated with textures that attest to melt crystallization. This reinforces the interpretation that the CCD is locally derived, i.e., it represents an in-source subhorizontal rheologically weak layer of migmatites and parauthoctonous granites that formed during the orogenic thickening. The CCD likely triggered the formation of an orogenic plateau and a geological setting in which high temperature conditions could be sustained for tens of millions of years. In such a setting, continuous heat supply from radiogenic decay might have been the main heat source for the compositionally diverse magmatism during most of the orogenic evolution of the Araçuaí belt.
Citation
Cavalcante , C , Meira , V T , Magalhães , N , Hollanda , M H B M & Oliveira , E 2021 , ' The role of Ediacaran synkinematic anatectic rocks and the late-orogenic charnockitic rocks in the development of the hot Araçuaí belt ' , Precambrian Research , vol. 365 , 106396 . https://doi.org/10.1016/j.precamres.2021.106396
Publication
Precambrian Research
Status
Peer reviewed
ISSN
0301-9268Type
Journal article
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Copyright © 2021 Elsevier B.V. All rights reserved. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1016/j.precamres.2021.106396
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We appreciate the Brazilian funding through the agencies FAPESP – Fundação de Amparo a Pesquisa do Estado de São Paulo –, CAPES – Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior –, and CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico – (project numbers 2010/03537-7 and BEX 4190/11-4 to CC, 404767/2016-8 to VTM and 2010/50475-7 to MHBMH).Collections
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