Caracterización mineralógica y textural del yacimiento epitermal de baja sulfuración de la mina LOS RIOS UNO ubicada en el distrito minero Ponce Enríquez.

Abstract

Abstract: This study was based on the mineralogical, textural, and chemical characterization of the gold deposit at the Los Rios Uno Mine, located in the Ponce Enríquez Mining District, Ecuador; using analytical techniques of optical microscopy (thin sections and polished sections), X-ray diffraction (XRD), X-ray fluorescence (XRF), and short-wave infrared (SWIR) spectroscopy, which determined the paragenetic evolution and ore precipitation mechanisms. Three stages of hydrothermal evolution were identified: a high-temperature magmatic-hydrothermal event (300 400 °C) with actinolite, secondary biotite, and epidote; a main epithermal phase (200 280 °C) with sericite, illite, chamosite, quartz, and sulfides (pyrite, arsenopyrite, pyrrhotite, chalcopyrite, sphalerite), where boiling and cataclasis promoted the precipitation of native gold (10 15 &#956;m) in microfractures; and a late cooling stage (< 200 °C) with kaolinite and carbonates. The results confirm a low-sulfidation epithermal deposit with thermal telescoping overprinted on a higher-temperature magmatic-hydrothermal event. It is concluded that cataclastic textures and boiling controlled bonanza precipitation, and the use of SWIR spectral vectors and deep exploration toward the northeast is recommended.