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


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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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):221-49.
Research Papers
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