Regional characterization of suspected land Punta del Este ( east of the Republica Oriental del Uruguay )

Field Suspect Punta del Este (TSPE) is located in the easternmost portion of Uruguay (Figure 1). This is bounded to the west by Shear Zone Punta del Este-Cordillera (Masquelin, 1990; Preciozzi et al., 1999; 2002), while the east with Rocha makes Formation (Hasui et al, 1975;.. Sanchez-Bettucci and Mezzano, 1993). The TSPE is represented by gneisses and Migmatites formed in the range of 1100 and 630 Ma (Preciozzi et al, in prep.) and have been intensively reworked during Rio Doce orogeny (ca. 600 Ma). Field Suspect Punta del Este (TSPE) is separated from the Neoproterozoic granitoids or granitoids by central Shear Zone Punta del Este-Cordillera represented by a thin strip of mylonite s and gneisses mylonitic able to anatexis. Granitoids are sub alkaline trend throughout of this guideline. The mylonitic foliation has a general direction between N15ºE and N40ºE with sub vertical slope where development ductile quartz and muscovite bands observed (Figure 2). The base of TSPE consists essentially of porphyritic granitoids deformed with biotite and muscovite, and ortho gneisses oftalmíticos granitoids, showing an attenuation of that reaching isotropic deformation terms. From studies in zircons from a sample of ortho gneisses (UCUR 03) by U / Pb conventional and SHRIMP ages of 753 ± 14 Ma for the edge obtained (consistent with the conventional age) and 1000 Ma for zircon center. This has allowed us to recognize in the protoliths one Grenvillian heritage in this area, preserved during crustal melting processes. Also, new U / Pb (Preciozzi et al., In prep.) Data show a orogénesis penicontemporánea to the Brasiliano cycle would be responsible for most of the generation of the rocks that make up the TSPE