Advancing Gold Mineralization Detection in Northern New Brunswick Through Portable X-ray and Micro-X-ray Fluorescence Spectrometry with Multivariate Compositional Data Analysis (CoDA) and Clustering for Pathfinder Elements and Alteration Analysis

The New Brunswick segment of the Canadian Appalachians contains a variety of gold deposits and occurrences that formed at different stages of the Appalachian orogeny. The Tobique-Chaleur Zone, situated in the northern part of New Brunswick hosts several orogenic and epithermal gold mineralization systems that are spatially related to large-scale crustal faults or their subsidiary splays, e.g., the Rocky Brook-Millstream Fault. Although gold mineralization in northern New Brunswick is hosted by auriferous quartz veins, finding pathfinder elements, indicator minerals, and alteration associated with gold mineralization remains challenging. Herein, the portable X-ray fluorescence (pXRF, Olympus Vanta™) spectrometer, in conjunction with micro-X-Ray Fluorescence (µXRF) Energy Dispersive Spectrometry (EDS), was applied to selected core intervals from four gold systems in the region, namely the Williams Brook, McIntyre Brook, Mulligan Gulch, and Simpson Field occurrences. We generated pXRF-based multielement datasets from selected intervals, then applied compositional data analysis (CoDA), including principal component analysis (biplots) and cluster analysis, to interpret them. Although the pXRF analysis and subsequent multivariate compositional data analysis provide geochemical patterns and highlight indicator elements associated with gold mineralization, the study also includes a comprehensive mineralogical analysis. The pXRF geochemical data help the interpretation of the mineralogy, but the explicit mineralogical composition is confirmed through detailed petrographic and μ XRF analyses. Gold-bearing minerals were further identified by µXRF-EDS analysis, revealing that gold is mainly associated with sulfide minerals, namely pyrite, chalcopyrite, pyrrhotite, stibnite, and arsenopyrite. In addition to the above, our mineralogical studies further indicate that fine-grained muscovite and illite, produced by potassic and silicification alteration styles, are associated with gold-bearing quartz veins.