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Paleo- and Neoproterozoic magmatic and tectonometamorphic evolution of the Isla Cristalina de Rivera (Nico Pérez Terrane, Uruguay) |
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| Authors: | Pedro Oyhant?abal Martin Wagner-Eimer Klaus Wemmer Bernhard Schulz Robert Frei Siegfried Siegesmund |
| Institution: | 1. Departamento de Geología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay 2. Geoscience Centre of the Georg-August University G?ttingen, Goldschmidtstr. 3, 37077, G?ttingen, Germany 3. Institut für Mineralogie der TU Bergakademie, Freiberg, Saxony, Germany 4. Department of Geography and Geology, University of Copenhagen, Oester Voldgade 10, 1350, Copenhagen, Denmark |
| Abstract: | The Isla Cristalina de Rivera crystalline complex in northeastern Uruguay underwent a multistage magmatic and metamorphic evolution. Based on SHRIMP U–Pb zircon, Th–U–Pb monazite (CHIME-EPMA method) and K–Ar age data from key units several events can be recognized: (1) multistage magmatism at 2,171–2,114?Ma, recorded on zircon of the granulitic orthogneisses and their 2,093–2,077?Ma overgrowths; (2) a distinct amphibolite facies metamorphism at ~1,980?Ma, recorded by monazite; (3) greenschist facies reworking and shearing at ca. 606?Ma (monazite and K–Ar on muscovite) along the Rivera Shear Zone, and finally (4) intrusion of the post-tectonic Sobresaliente and Las Flores granites at around 585?Ma. Lithological similarities, geographic proximity and coeval magmatic and metamorphic events indicate a similar tectonometamorphic evolution for the Isla Cristalina de Rivera, the Valentines Block in Uruguay and the Santa María Chico Granulitic Complex in southern Brazil, since at least 2.1?Ga. |
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