Epithermal fluids evolution related to an IOCG system in Cerro Colorado Chico

• Autores: Bazan Santa Cruz, Orlando, Torres Guerra, Jesús Alberto
• Formato: artículo
• Fecha de Publicación: 2023
• Institución: Universidad Nacional Mayor de San Marcos
• Repositorio: Revistas - Universidad Nacional Mayor de San Marcos
• Lenguaje: español
• OAI Identifier: oai:ojs.csi.unmsm:article/24710
• Enlace del recurso: https://revistasinvestigacion.unmsm.edu.pe/index.php/iigeo/article/view/24710
• Nivel de acceso: acceso abierto
• Materia: Cerro Colorado Chico; epithermal fluids; fluid inclusions; microthermometry; quartz POD; cuarzo POD; fluidos epitermales; inclusiones fluidas; microtermometría

Cerro Colorado Chico located in Ancash region, northern coast of Peru. Brecciated siliceous bodies occur with restricted halos of advanced argillic alteration silica-pyrophyllite-alunite and extensive silica-sericite-pyrite alteration, breccias and hematite bodies, hematitized horizons into volcano-sedimentary rocks of the Casma Group. A microthermometry study of fluid inclusions has been carried out in 4 samples with a total of 55 primary and secondary fluid inclusions in quartz. Two stages are distinguished, the first at mesothermal temperatures between 605° and 560° C with salinities of 47.66% to 44.82% NaCl eq., and the second at epithermal temperatures between 329° and 138° C with salinities of 0.7%. to 9.73% NaCl eq., with complex fluids evolution processes as cooling, dilution, mixing and boiling. This study permit to explain the processes that take place in the epithermal environment of IOCG-type magmatic-hydrothermal systems from fluids derived of silica-rich silicate melts that partition from poorly differentiated magmas, when decompressed separate into a dense saline liquid phase and a low-density vapor phase that rises to the upper levels and is responsible for the formation of the brecciated siliceous bodies and the advanced argillic alteration.