Estudio mineralógico y paragenético de estructuras mineralógicas en el sector Bellavista, cantón Palanda

Abstract

Abstract: This study provides a mineralogical and paragenetic characterization of the mineralized structures in the Bellavista sector, Palanda Canton (Zamora Chinchipe, Ecuador), using X-ray diffraction (XRD), X-ray fluorescence (XRF), macroscopic description, thin-section petrography, and polished-section analysis of host-rock and vein samples. The host rock is an intermediate-composition diorite (SiO2 50․6-54․6%) which is cut by granodiorite-tonalite dikes belonging to the Zamora Batholith․ The diorite is propylitically- to calcically-altered with chlorite actinolite epidote diopside and sericite (200-350 °C)․ The ore includes chalcopyrite bornite magnetite and native gold along with covellite and supergene iron oxides․ A mineralogical-textural assemblage defined three stages: the igneous hydrothermal-mineralizing and the supergene stages․ Native gold represents approximately 30 45% of the area occupied by opaque minerals observed in ore microphotographs from samples M03, M04, and M05, and is mainly associated with microfractures and margins of copper sulfides, suggesting late-stage precipitation. These characteristics support the interpretation of the mineralization as a Cu-Au porphyry-type system associated with the Jurassic metallogenic belt of Zamora Chinchipe and provide a basis for future regional exploration campaigns.