Magmatismo devónico de las Sierras de Córdoba: fuente posible de flúor de las mineralizaciones mesozoicas. El ejemplo del batolito Cerro Áspero.

CONIGLIO, JORGE; D'ERAMO, FERNANDO; PINOTTI, LUCIO; DEMARTIS, MANUEL; PETRELLI, HUGO

Buenos Aires

Congreso; VIII Congreso de Mineralogía y Metalogenia; 2006

The main Mesozoic epithermal fluorite veins of southern Sierras Pampeanas occur in porphyritic biotite monzogranites belonging to the Cerro Aspero batholith (Upper Devonian). The fluorite veins were formed by fluid-rock interaction processes with the fluids being dominantly composed of meteoric water. The chemical composition of the granitic rocks and biotite of the Cerro Aspero batholith are similar to the granites from other fluorite districts in the world, which usually belong to the high K magmatic series.The Cerro Aspero batholith is an anormally F-rich specialized granite. The average F content in these granitic rocks is 1210 ppm, which is higher than in the hosting metamorphic rocks and in some Famatinian granitoids of the Sierras de Córdoba. We suggest that the breakdown of F-rich biotite and fluor-apatite by hydrothermal alteration in fracture zones is the most plausible source of fluorine for the epithermal veins formation. According to this idea it is not necessary to invocate an hypothetical external source.