Produção Nacional
Polycyclic evolution of Camboriú Complex migmatites, Santa Catarina, Southern Brazil: integrated Hf isotopic and U-Pb age zircon evidence of episodic reworking of a Mesoarchean juvenile crust
2013; Sociedade Brasileira de Geologia; Volume: 43; Issue: 3 Linguagem: Inglês
10.5327/z2317-48892013000300002
ISSN2317-4889
AutoresMiguel Ângelo Stipp Basei, Mário da Costa Campos Neto, Angela Pacheco Lopes, Allen P. Nutman, Dunyi Liu, Kei Sato,
Tópico(s)Geochemistry and Elemental Analysis
ResumoCamboriú Complex is the only gneissic-migmatitic inlier within the Neoproterozoic Brusque Group supracrustal rocks, in the northernmost part of the Dom Feliciano Belt, Southern Brazil.It comprises Morro do Boi migmatites and diatexitic Ponta do Cabeço Granite.Zircon U-Pb dating of migmatites and associated granitic neosomes shows that the crustal evolution started in the Paleo-Mesoarchean (from 3.3 to 3.0 Ga), continued with events through the Neoarchean and Paleoproterozoic, and ended in the Neoproterozoic (from 0.64 to 0.61 Ga).Integration of zircon Hf isotopic data and U-Pb ages indicates that juvenile crustal accretion was restricted to the Archean and that, afterwards, the intracrustal reworking predominated.The exception to this is the ca.1.56 Ga xenoliths (basic dike remnants?),whose magmatic zircons have juvenile Hf isotopic signatures.This basic magmatism marks an extension of the earlier Precambrian complex.Although the Camboriú Complex is dominated by early Precambrian crustal additions, it was so strongly reworked in the Neoproterozoic that melts derived from it intruded the adjacent Neoproterozoic Brusque Group supracrustal rocks.Due to this strong overprint, the Camboriú Complex is regarded as a Neoproterozoic (Ediacaran) geotectonic unit.In terms of its history, the Camboriú Complex most closely matches the Atuba Complex, the basement of Curitiba microplate that occurs further to the North, close to the Ribeira Belt, which is another Neoproterozoic orogen in Southern Brazil.
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