Evaluación geoquímica-metalogenética de la subcuenca Antabamba para determinar clusters potenciales de pórfidos de cobre-molibdeno, Apurímac

Abstract

This study was conducted in the Antabamba sub-basin, located in the Apurímac region, with the aim of identifying potential exploratory clusters for copper porphyries in the proximity of Andahuaylas-Yauri Batholith. In this area, intrusive rocks of diorites and tonalites related to Eocene-Oligocene mineralization outcrop, alongside the Cu-Mo porphyry deposits of La Yegua, Los Chancas, Antilla, Utupara, and Trapiche. The geochemical information from 962 sediment samples collected from streams, provided by INGEMMET between 2008 and 2014, was standardized. These samples were analyzed using mass spectrometry (ICP-MS) with aqua regia dilution. Subsequently, values below the detection limit were corrected, resulting in a global average of 161 ppm Cu, 33 ppm Pb, 117 ppm Zn, and 45 ppm As. To delineate the exploratory clusters, a probability map was created by calculating mineralogical index based on the chemical association of Cu-Pb-Zn-Mo-As-Sb-Bi. lt was concluded that micro-basin 02 exhibits the highest potential, containing an average of 324 ppm copper, 41 ppm Pb, 55 ppm Zn, and 68 ppm As. Alterations related to porphyries are evidenced, such as silicification in the western part of the sub-basin, propylitic-argillic alterations in the center, and granodiorite-diorite rocks with average values of 685 ppm Cu, 131 ppm As, and 35 ppm Zn, with maximum values found in areas of potassic-argillic alteration.