Geochemical Mapping of the North-Central Portion of the Yukon-Tanana Upland, Alaska, United States: Application of Exploratory Data Analysis (EDA) to REE and PGE Mining Prospection

The demand for Rare Earth Elements (REE) and Platinum Group Elements (PGE) in advanced technologies and clean energy has highlighted concerns about China's dominance in the REE market. To reduce dependence on foreign mineral supplies crucial for national security and the economy, the United States has sought to enhance its geological knowledge and identify undiscovered critical mineral resources. This thesis focuses on the north-central region of the Yukon-Tanana Uplands in Alaska, a region of profound geological intrigue, holding the potential for significant critical mineral resource deposits. It employs advanced geochemical mapping techniques and Exploratory Data Analysis (EDA) to assess this potential with geochemical data provided by the Earth Mapping Resources Initiative (Earth MRI), carried out by the United States Geological Survey. The study identifies distinct geochemical associations, including REE´s, REE pathfinders and PGE pathfinders, through multivariate analysis (PCA) and validates these associations through bivariate analysis. Tantalum (Ta) and Titanium (Ti) are excluded from further analysis due to weak correlations. Univariate analysis generates two types of geochemical maps for REE and PGE associations, revealing distinct patterns and anomalies. Hafnium (Hf) and Zirconium (Zr) exhibit unique and different patterns within the REE group, while Chromium (Cr) differs from typical PGE patterns. Using ArcGIS, the study combines dimensionally reduced geochemical elements from EDA to produce conclusive mining potential maps. The REE mining map identifies six anomalous zones, with only zones I and II as potential candidates for hosting REE mineralization. In the PGE mining map, three anomalous zones, including zones I and II, are recognized as viable PGE prospects. Overlaying mining potential maps onto the geological map confirms the association of REE anomalous zones with Granitic peralkaline/alkaline rocks, known for their REE-hosting characteristics. Additionally, PGE occurrences are linked not only to igneous rocks but also to sedimentary and metamorphic rocks, especially those with mafic and ultramafic compositions, common PGE hosts.