Estudio mineralógico y paragenético de las estructuras mineralizadas en la concesión minera Pinta Brava II, distrito minero Chinapintza, cantón Paquisha, provincia de Zamora Chinchipe, Ecuador

Abstract

Abstract: This study characterizes the mineralogy and paragenetic sequence of the mineralized structures in the Pinta Brava II concession, located in the Chinapintza district, Zamora Chinchipe province. The study combined field observations, targeted sampling, and petrographic analyses using transmitted and reflected light. In the surveyed areas, quartz-carbonate veins hosted within volcanic and subvolcanic rocks were identified. The mineralization consists mainly of galena, sphalerite, pyrite, and chalcopyrite, in addition to small amounts of covellite. The gangue consists of quartz and pink carbonates, preliminarily interpreted as possible rhodochrosite. Based on textural relationships, a relative sequence was proposed that includes propylitic alteration of the host rock, early formation of pyrite, subsequent precipitation of sphalerite, chalcopyrite, and galena, and a late phase of covellite consistent with possible supergene replacement. The fine chalcopyrite inclusions in sphalerite are comparable to the chalcopyrite disease texture, although they do not allow for the determination of a specific temperature. Taken together, the results suggest a preliminary affinity with a low- to intermediate-sulfidation polymetallic epithermal system.