Estudio geoquímico y petrográfico de las rocas subvolcánicas del área Arquia-Chirapotó (Antioquia-Caldas)

Se presentan en este trabajo los resultados de un estudio geoquimico y petrografico realizado en un area de 25 Km. cuadrados al norte de Marmato (Caldas) donde se encuentra un ambiente geologico con caracteristicas muy similares a las de esta importante zona aurifera. Un total de 50 muestras de roca fueron analizadas por el metodo de absorcion atomica para determinar el contenido de metales basicos, principalmente cobre y molibdeno. Simultaneamente se estudiaron petrograficamente 41 muestras de rocas porfidicas que permitieron definir en ellas una extensa alteracion propilitica, secundaria en importancia se encontro una alteracion filica. El analisis estadistico de los resultados encontrados se efectuo mediante los metodos de Lepeltier, promedio movil, y el analisis factorial. El tratamiento indica una relacion entre los metales analizados que permite establecer dos asociados muy importantes: 1. cobre-molibdeno-plata, 2. zinc-plomo-plata. / Abstract: The results of a geochemical and petrographic study of on 25 sq km area North of Marmato (Caldas), with a similar geological environment as the well known gold producing area are presented in this thesis. A total of 50 porphyritic rock samples were analyzed by atomic absorption to determine the contents of the following Basic metals: copper, molybdenium, zinc, lead and silver with the greatest interest in the first two. Forty-one of the same samples were analyzed petrographically demonstrating that they were affected by an extensive propylite alteration followed by a filic phose of secundary important. The results were analyzed by Lepeltier’s, the moving average and factorial analysis methods. The treatments indicate, importantly that the following associations are statically related: 1.Cooper – molybdenium – silver, 2.Zinc-lead-silver. The distribution of these associations is zonal with the maximum concentration of the first towards the Q. Chirapoto, while the second is Strong in the Q. la Guavita. These two associations indicate the existent of areas with geochemical anomalies which are correlated with lode mineralization.