Petrophysical Signatures and Mineral Endowment: The Piché Group, Augmitto–Bouzan Sector, Québec, Canada

Hydrothermal alteration plays a crucial role in the precipitation of gold and other metals, particularly within orogenic gold deposits hosted in mafic and ultramafic rocks. This alteration significantly modifies the rock matrix, leading to changes in its petrophysical properties. In this study, we focus on two key processes: quartz‐carbonate vein formation and sulfidation, both of which have distinct effects on geophysical measurements. The investigation centres on the Piché Group within the Augmitto–Bouzan sector of Rouyn Property, a primary target for gold exploration. Quartz‐carbonate vein formation, characterized by the direct precipitation of resistive minerals such as quartz and carbonates, has a pronounced effect on resistivity logs, leading to increased resistivity values. These changes are also evident in sonic logs, where P‐wave and S‐wave velocities increase due to the presence of these minerals. Sulfidation, in contrast, reflects metasomatic alteration of the host rock and is primarily captured through induced polarization (IP) and spontaneous potential (SP) logs. The crystallization of sulfide minerals, such as pyrite and arsenopyrite, not only leads to increased IP and decreased SP values but also results in a high degree of variability in IP values, reflecting the heterogeneous distribution of sulfides in the host rocks. These findings are further supported by micro‐XRF data, confirming the presence and distribution of sulfide minerals in key alteration zones. Our results suggest a relationship between these petrophysical signatures and gold endowment, with increased resistivity (presence of quartz‐carbonate veins) and elevated IP values (sulfidation) correlating with a higher probability for gold concentrations. By focusing on the distinct effects of quartz‐carbonate veins and the sulfidation process, this study provides valuable insights into the identification of alteration zones and their potential for mineralization. These results contribute to a deeper understanding of alteration within the Piché Group and offer a framework for more targeted exploration efforts in similar geological environments.