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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Reviewing the puzzling intracontinental termination of the Aracuai-West Congo orogenic belt and its implications for orogenic development

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Author(s):
Cavalcante, Carolina [1] ; Fossen, Haakon [2] ; de Almeida, Renato Paes [3] ; Hollanda, Maria Helena B. M. [3] ; Egydio-Silva, Marcos [3]
Total Authors: 5
Affiliation:
[1] Univ Fed Parana, Dept Geol, Ave Coronel Francisco H dos Santos 100, BR-81531980 Curitiba, Parana - Brazil
[2] Univ Bergen, Museum Nat Hist, Dept Earth Sci, Allegaten 41, N-5007 Bergen - Norway
[3] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508900 Sao Paulo, SP - Brazil
Total Affiliations: 3
Document type: Review article
Source: Precambrian Research; v. 322, p. 85-98, MAR 2019.
Web of Science Citations: 0
Abstract

Palinspastic reconstructions suggest that the late Proterozoic-Cambrian Brasiliano/Pan-African orogenic belt in southeast Brazil and west Congo terminated northwards into an embayment within the Sao Francisco-Congo cratonic unit. The orogenic shortening that created the Aracuai-West Congo orogen in this embayment has been explained by tightening of the horseshoe-shaped Sao Francisco-Congo craton in a fashion referred to as ``nutcracker tectonics{''}. We show that this model is incompatible with the general orogenic evolution proposed in recent literature, which involves (1) similar to 50 m.y. of subduction of oceanic crust and associated arc formation, followed by (2) collisional orogeny and crustal thickening. Quantitative considerations show that the original nutcracker model is too rigid to explain even the second, crustal thickening part, let alone any long pre-collisional history. To soften the model, we suggest that the so-called Sao Francisco - Congo bridge was broken by a similar to 150 km wide orogenic corridor along the current African Atlantic margin. This corridor adds sufficient mobility to the system to explain the orogenic thickening of the crust to 60-65 km. However, even with this additional softening the confined nature of this orogen is incompatible with prolonged arc development. We therefore suggest that oceanic crust was nonexistent or very limited in the Macaubas basin, and reject the widely published model involving similar to 50 m.y. of subduction of oceanic crust and related arc development. Instead, we find strong support for a hot intracontinental orogen model in the currently available P-T, geochronologic, petrographic and structural data. In this model, extensive melting and flow of the middle crust is likely to have caused spreading of the upper crust in an orogenic setting that was created by collisions along the N, W and S margins of the Sao Francisco craton from similar to 630 Ma. (AU)

FAPESP's process: 10/03537-7 - Tectonoseismic Study of the Carlos Chagas Leucogranite and Adjacent Units, Araçuaí Belt (Eastern Brazil).
Grantee:Geane Carolina Gonçalves Cavalcante
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 14/10146-5 - Rheological evolution of the continental crust: microstructures and deformation mechanisms in the Além-Paraíba-Pádua shear zone (Ribeira Belt)
Grantee:Geane Carolina Gonçalves Cavalcante
Support type: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 15/23572-5 - From orogeny to rifting and drifting: a study of the Eastern Brazilian orogenic belt and comparison with the North Atlantic Scandinavian orogenic belts/continental margins
Grantee:Renato Paes de Almeida
Support type: Research Grants - Visiting Researcher Grant - International
FAPESP's process: 13/19061-0 - Rheological evolution of the continental crust: microstructures and deformation mechanisms in the Além Paraíba-Pádua shear zone (Araçuaí-Ribeira belt)
Grantee:Geane Carolina Gonçalves Cavalcante
Support type: Scholarships in Brazil - Post-Doctorate