Daniel Alejandro Castano Madrigal MSc

High-grade gold controls and spatial chemical zonation at the Snip North prospect of the Iskut project

D. Castano Madrigal1
1Department of Earth, Environmental and Resource Sciences, The University of Texas at El Paso, El Paso, Texas, United States of America, El Paso, Texas, United States of America

The Iskut project, located in northwestern British Columbia, Canada, is located in a tectonically active region within the Intermountain Belt, formed by the convergence of the Pacific and North American plates. This subduction environment has generated a complex geologic history, characterized by intense magmatic activity, faulting and folding. Lithological units in the area include a Triassic-Jurassic volcano-sedimentary sequence composed of shales, sandstones and basalts, intruded by Cretaceous monzodiorites and younger intrusive bodies related to hydrothermal events.

At the Snip North prospect, multiple vein systems intersecting all lithologies have been identified, defining at least three stages of mineralization. Stage 1 includes veinlets with pyrite, chalcopyrite and carbonates, representing the earliest stage. Stage 2, the most economically significant, is composed of quartz, chalcopyrite, pyrite, sphalerite, gold and carbonates. Finally, Stage 3 corresponds to late veinlets dominated by carbonates, quartz and pyrite, occasionally accompanied by chalcopyrite.

Spatially, Stage 2 veinlets with white mica halos (~20 cm wide) predominate at shallow levels and are associated with the highest gold grades. At greater depths, veinlets with secondary biotite halos are observed, linked to pervasive biotite alteration in the host rock, which is cut by vein-related alterations. Monzodiorite quartz intrusions present at depths greater than 1 km are associated with increased molybdenum concentrations, suggesting their connection to deep stages of mineralization.

Micro-XRF analysis and detailed observations have revealed that copper is not always associated with sulfides, as it also appears disseminated in the host rock, suggesting the presence of sulfosalts. In addition, high concentrations of magnetite have been identified distributed throughout the deposit, along with smaller zones of hematite, indicating local variations in oxidation conditions during hydrothermal events. These features highlight the complexity of the deposit and underscore the need for further analysis to understand the controls on mineralization.

This geological and mineralogical context provides a basis for developing more efficient exploration strategies, optimizing resource estimation and advancing the comprehensive understanding of the Snip North prospect within the Iskut project.