Paleoproterozoic crustal evolution and Mesoproterozoic overprint in the Roosevelt-Guariba Transpressive Belt, Juruena Terrain, Southeastern Amazonas, Brazil

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Marcelo Esteves Almeida
Antônio Charles da Slva Oliveira
João Orestes Schneider dos Santos
Gilles Ruffet
Joseneusa Brilhante Rodrigues

Abstract

The Juruena Terrain (Rondônia-Juruena Province) in the southeastern Amazonas State shows a NW-SE dextral shear zones system denominated Roosevelt-Guariba Transpressive Belt (RGTB). The RGTB was generated in response to intracontinental crustal reworking, juxtaposing Paleoproterozoic Juruena granitic-gneiss and chronocorrelated supracrustal associations. This granitic-gneiss basement shows high-K calc-alkaline (Teodósia Suite) to transitional I- to A-type (Igarapé das Lontras Suite) signatures, produced in a continental magmatic arc setting around 1760-1740 Ma (zircon, titanite; U-Pb SHRIMP, LA-ICP-MS). New geochronological data about of the deformation and metamorphic rocks in the RGTB were obtained from migmatite paragneisses, amphibolites, S-type leucogranite (Quatro Cachoeiras Complex and Itamaraty Suite; zircon U-Pb SHRIMP) and protomylonites and mylonites (Igarapé das Lontras and Teodosia protholiths; amphibole-muscovite-sericite Ar-Ar step heating). The results suggest that Southeastern Amazonas (northern Juruena Terrain) was metamorphised/deformed during 1530-1460 Ma under temperatures of 900 oC (zircon) to 580oC (hornblende) and 420oC (muscovite). The geochronological data show that the granite-gneiss basement (continental magmatic arc) and supracrustal rocks (foreland basin) were reworked by a regional event with age interval of 1530 Ma (high grade and anatexis) to 1460 Ma (medium grade). Finally, the Juruena Terrain is affected by a younger low-T event (1300 Ma, muscovite Ar-Ar step heating) with wide NE-trending structures (e.g. Buiuçu Shear Zone). This 1.3 Ga event suggests a continental reactivation caused by the pericratonic deformation related to Candeias/Sunsás Orogeny during the Columbia Supercontinent break-up, before of the Rodinia Supercontinent assembly. In summary, the Juruena Terrain in the southeast Amazonas shows a complex metamorphic and structural intracontinental evolution, involving polycyclic events since late Orosirian to Ectasian in a convergent tectonic setting. Therefore, the Juruena Terrain shows similar accretionary histories with others orogens and has apparent long-lived connections with Laurentia (Yavapai Province) and Baltica (Transscandinavian Igneous Belt), forming the core of the Columbia Supercontinent.

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How to Cite
Esteves Almeida, Marcelo, Antônio Charles da Slva Oliveira, João Orestes Schneider dos Santos, Gilles Ruffet, and Joseneusa Brilhante Rodrigues. 2022. “Paleoproterozoic Crustal Evolution and Mesoproterozoic Overprint in the Roosevelt-Guariba Transpressive Belt, Juruena Terrain, Southeastern Amazonas, Brazil”. Journal of the Geological Survey of Brazil 5 (3). https://doi.org/10.29396/jgsb.2022.v5.n3.5.
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Author Biographies

Marcelo Esteves Almeida, Geological Survey of Brazil-CPRM

Av. Pasteur 404, Urca, CEP 22290-255, Rio de Janeiro, RJ, Brazil

Antônio Charles da Slva Oliveira, Geological Survey of Brazil-CPRM

Av. André Araújo 2160, Aleixo, CEP 69060-001, Manaus, AM, Brazil

João Orestes Schneider dos Santos, University of Western Australia

35 Stirling Highway Perth WA 6009, Perth, Australia

Gilles Ruffet, Université de Rennes I, CNRS (CNRS/INSU) UMR 6118

Géosciences Rennes, 35042 Rennes Cedex, France

Joseneusa Brilhante Rodrigues, Geological Survey of Brazil-CPRM

Setor Bancário Norte - SBN Quadra 02, Bloco H - Asa Norte, Ed. Central Brasília, CEP 70040-904, Brasília, DF, Brazil