FORMACION DE MEGACRISTALES DE FELDESPATO POTASICO EN EL SECTOR SUR DEL BATOLITO CERRO ASPERO-ALPA CORRAL (32°40'S y 64°50'W), SIERRAS PAMPEANAS, CÓRDOBA, ARGENTINA

PINOTTI LUCIO PEDRO; ANA MARÍA ESPARZA; CONIGLIO JORGE

ESTUDIOS GEOLOGICOS

CONSEJO SUPERIOR INVESTIGACIONES CIENTAFICAS

Lugar: Madrid; Año: 1992 p. 211 - 219

0367-0449

The surrounding rocks of studied area are composed by a metamorphic sequence whichincludes gneisses, schists, amphibolites, marbles and heterogeneous migmatites in non-conformity intruded by a granitic pluton. All this sequence is dated as having late-Precambricto mid-Paleozoic age.Three facies, mostly of monzogranitic composition, were identified. This study focuseson the porphiric facies; detailed petroestructural studies being performed, the orientationof large microcline crystal and associated microgranular enclaves being measured.Different primary flow directions were determined with track variation of microcline megacrystal and enclaves from subvertical to nearly horizontal positions.These changes have been interpreted as a convective system within the pluton.The presence of a marked planar fabric in microcline megacrystals along with phenomena such a size-variation of crystal, synneusis, crystal trending at the enclave´s border andcrystal accumulation, proves their early magmatic origino The enclaves show a cinematic ofdeformation produced by simple shear.