Geochemical Assessment of Dolerite from Oghi, Mansehra, Khyber Pakhtunkhwa, Pakistan

Abstract

A detailed ICP-MS based trace element geochemical analysis of sixteen dolerite samples (SS1–SS16) from Oghi, Mansehra with the primary objective of identifying and interpreting critical minerals as defined by the United States Geological Survey (USGS) Final 2025 List of Critical Minerals have been conducted. A total of 68 minerals were measured across all samples, with concentrations reported in parts per million (ppm) and qualitative designations of Above Detection Limit (ADL), and Below Detection Limit (BDL). Out of the 60 minerals on the USGS 2025 critical minerals list, 56 are represented by measured elements within this dataset, making this the first systematic critical mineral assessment of mafic intrusions in the Oghi Mansehra region. Palladium was detected in 15 of 16 samples (0.0185–0.1873 ppm), co-occurring with Platinum (11 samples) and Ruthenium/Iridium (6 samples each), indicating a pervasive PGE signature linked to sulfide-phase control (sulfur ADL in 10/16 samples). Copper appears in all samples (mean 0.239 ppm, max 0.5458 ppm), alongside elevated Te, Sb, Ag, and As. REEs show universal Eu, Gd, and Y detection, plus V and Ti. Niobium occurs in 12 samples (up to 0.1292 ppm in SS2), with moderate Ta and BDL Cr. High K (ADL in 10/16 samples), universal Rb (mean 0.251 ppm), and universally ADL P were also observed. Fe, Ca, Na, and S levels confirm a ferro-magnesian mafic composition, while low Th/U in SS1 (Th: 0.0251 ppm, U: 0.4130 ppm) suggests possible secondary uranium mobility. Nonetheless, the findings show that dolerites from Oghi can serve as meaningful repositories of critical elements and provide a baseline for future investigation. Recommended follow-up work includes denser sampling, identification of mineral host phases, sequential extraction, fluid inclusion and isotopic studies, and structural mapping, all of which are necessary before any responsible assessment of resource potential can be made.