Por: Maylin Mendoza Mondragón, Nexa Resources.

Abstract

This study aims to characterize, through the use of lithogeochemistry, the magmatic series and the host rock that took place in the formation of the Cerro Lindo VMS; in addition, alteration lithogeochemistry was performed to determine the relationship between mineralogy, lithogeochemistry and alteration intensity, obtaining as a result, vectors towards the center of the system. The primary purpose is to bring this 2D information from lithogeochemical diagrams into a 3D approach, and thus establish correlations with other controls on mineral occurrence (structural, geophysical, geochemical and lithological). 

From the analysis and interpretations it was determined that Cerro Lindo belongs to a calc-alkaline magmatic series with a high K content, the source rock definitely corresponds to felsic volcanic with a degree of differentiation from andesite to rhyodacite according to the degree of proximity to the economic zones; that is to say, the deposit is located in the oldest felsic bimodal level of the Casma basin, and it is these first stages of the fracture that are usually better enriched in contents of economic mineralization mainly of base elements followed by the presence of Ag*-Au; it is precisely this location that makes it much more powerful than other VMS in the area.

The SerK+ChlFe (Py) alteration halo has greater thickness and dominance on lower angle deep faults, which have brought economic Zn-Cu mineralization (NW-SE and NE-SW), faults related to high grade bodies and high chargeability zones; while the shallow NW-SE faults, of higher angle, that carry low grade mineralization and related to edge bodies of low chargeability would correspond to the Ser-Chl alteration and towards the more distal zones of the system, the SerNa-Chl Mg alteration appears.