Caracterización estructural y mineralógica de las vetas jorupe – tres reyes y soroche en el Distrito Minero Zaruma – Portovelo, Provincia de El Oro Génesis Bermeo Bermeo Granda

Abstract

The Zaruma-Portovelo mining district has been of great interest to Ecuador economy for over 500 years. It has remained in constant exploitation and exploration by several local and international companies. It is located in the El Oro province, namely in Zaruma and Portovelo, west of the Western Cordillera. The mining district is composed of a series of veins and is defined as an intermediate sulfidation epithermal deposit, the veins are hosted in the Portovelo unit which belongs to the Saraguro group. The studied veins orientation suggests that their formation happened during a geodynamically active system with N-S strike with slight NE-SW variations controlled by the Piñas - Portovelo and Palestina - Puente Buza dextral reverse faults. This composite fault system is the main structural feature controlling mineralization. The dominant lithologies in which the Jorupe - Tres Reyes and Soroche veins are hosted are andesites, dacites, andesitic tuffs and volcanic breccias belonging to the Portovelo Unit. These rocks show developed hydrothermal alteration, mainly propylitic, subpropylitic and silicification. The paragenetic sequence of the Jorupe - Tres Reyes and Soroche polymetallic vein system is defined in five stages.