Cerro de los Viejos (38°28'S-64°26'O): cizallamiento dúctil en el sudeste de La Pampa.

HUGO TICKYJ,; LUIS DIMIERI; EDUARDO LLAMBÍAS,; ANA SATO,

Revista de La Asociación Geológica Argentina

Asociación Geológica Argentina

Lugar: Buenos Aires; Año: 1997 vol. 52 p. 311 - 321

0004-4822

The Cerro de Los Viejos (south-east of La Pampa province) are granitic and mylonitic gneisses that were developed in an intense ductile shear zone during late Palaeozoic times. The shearing event developed a planar fabric with mean orientation N34°0/27S0 and a mineral lineation N42°E/25°S0. Kinematic indicators, such as S-C fabrics and asymmetric porphyroclasts, indicate NE compression.The orientation of these structures is coincident with others in metamorphic rocks of the same region. The analysisof the deformational microstructures and mineral paragenesis shows that metamorphic conditions would have reached amphibolite facies. The orogenic features of the deformation could be related to active compression of Patagonia against South America in Late Palaeozoic times.