Tuesday, May 10, 2016

Uruguay's Nico Pérez Terrane was Largely Created During the Archean

The Nico Pérez Terrane (Uruguay): from Archean crustal growth and connections with the Congo Craton to late Neoproterozoic accretion to the Río de la Plata Craton


Oriolo et al


New U–Pb and first Hf data were obtained from the Nico Pérez and Piedra Alta terranes as well as from the Congo Craton. Results indicate that the Nico Pérez Terrane was mostly built during Archean episodic crustal growth and this crust underwent significant Paleo- and Neoproterozoic crustal reworking at ca. 2.2–2.0, 1.7 and 0.6 Ga. The Piedra Alta Terrane of the Río de la Plata Craton, in contrast, records only Paleoproteorozoic crustal growth. These evidences together with available geological, geochrological and isotopic data indicate the allochthony of the Nico Pérez Terrane. Furthermore, data point to an African origin of the Nico Pérez Terrane, particularly related to the southwestern Congo Craton. After Cryogenian rifting from the latter during Rodinia break–up, the Nico Pérez Terrane was accreted to the eastern Río de la Plata Craton along the Sarandí del Yí Shear Zone and underwent further crustal reworking during the evolution of the Dom Feliciano Belt.

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