Por: Elí Cerna y Williams Mata, Volcan Compañía Minera.

Abstract

Hydrothermal veinlets in porphyry copper deposits constitute an essential record of the magmatic-hydrothermal evolution associated with mineralization. This paper presents a technical systematization of their classification and evolutionary sequence (DQ → A → BMQ → B → C → D), based on a critical review of specialized literature and macroscopic observation of twenty representative samples from the collection of the Mineral Deposits Research Center (CIDM, Centro de Investigación de Depósitos Minerales) at the Universidad Nacional de Ingeniería (UNI). 

Published analytical data (mineralogy, physicochemical conditions, geochemistry, and instrumental techniques) obtained from the literature are integrated with the textural evidence and crosscutting relationships identified through macroscopic observation of the aforementioned samples. 

The main veinlet types are described, ranging from deep quartz (DQ) veinlets, which are poor in sulfides, to late sericitic veinlets with pyrite, identifying local variations and overlaps within the proposed sequence (Seedorff et al., 2005; Sillitoe, 2010; Reed et al., 2013; Cernuschi et al., 2023). Likewise, the early EDM (Early Dark Micaceous), PGS (Pale-Green Sericite), and GRS (Green Sericite) halos are characterized in terms of diagnostic minerals, spatial distribution, and their potential as early vectoring indicators. 

To illustrate regional variability, published studies documenting porphyry deposits in Peru, Chile, the United States, Indonesia, Argentina, Ecuador, and Canada were compared, as detailed in the bibliography. The results show that integrating veinlet and halo zonation with bibliographic evidence constitutes a useful tool for guiding exploration campaigns toward domains with greater Cu-Mo potential and for strengthening geometallurgical models. In this regard, preliminary operational criteria for vectoring and Cu-Mo domain modeling are discussed, aimed at optimizing target identification and the design of sampling and drilling programs. Finally, interpretative limitations derived from telescoping, remobilization, and exhumation are acknowledged, and priorities are proposed for analytical and chronological validation in future research.