Geología de los granitoides del sector septentrional de la Sierra Chica de Córdoba

PÉREZ, M.B.; RAPELA, C.W.; BALDO, E.G

Buenos Aires

Simposio; Simposio Internacional “Proto-Andean Margin of Gondwana”, XIII Congreso Geológico Argentino; 1996

Asociación Geológica Argentina

The northern sector of the Sierra Chica of Córdoba is characterized by a series of granitoid plutons of early Paleozoic age emplaced in a medium-grade polymetamorphic basement. The Iatter is composed of diopsidic marbles, tonalitic orthogneisses, biotite-muscovite schists and amphibolites. Textural relations and mineral associations suggest the following succession of events: (a) medium grade regional rnetamorphism (T = 500-700 °C, P = 4-6 kb); (b) Metasomatism in the marbles associated to the granitoid intrusion; (c) Strong ductile, medium grade rnylonitic deformation and (d) retrograde (epidote-chlorite) metamorphism. Four main plutonic units have been distinguished. A common characteristic to all of them is a foliation produced by ductile deformation and ubiquitous epidote in the mineral assemblages. Some plutons are dominated by rnetaluminous, medium-K calc-alkaline suites of hornblende-biotite tonalites, biotite tonalites, porphyritic granodiorites and granites. Dioritic enclaves are widespread. Others are more homogeneous, composed by peralminous, low-to-medium K trondhjemite, with scarce tonalitic enclaves.