Geología del área granítica y metamórfica al Oeste de Ciudad Rodrigo (Salamanca): II. Las rocas graníticas

Abstract

This paper deals with the petrography, geochemistry and petrogénesis in an area localized in the west side of Ciudad Rodrigo (Salamanca). Eight different faciès were found, some of them showed the following differentiation suite : granodiorite - monzonitic granite - leucogranite. Muscovitization, silicification and some type of albitization phenomena originated by late and postmagmatic processes are the more remarkable pétrographie aspects. From a geochemical point of view marked anomalies in the amount of such trace element as Li, Rb, Sr y Ba were found. Because of the behaviour of these elements during the partial melting, fractional cristallization and pegmatitic - neumatolytic processes, those anomalies could be explained. The whole granitic series may be considered as a very evolved epizonal granites belonging to a calcoalcaline suite contaminated by mesoerustal rocks and very transformed by postmagmatic processes.