Field Investigation of Volcanic Rocks and Their Economic Potential in Plateau State

The Jos Plateau in Plateau State, North Central Nigeria, is underlain by a suite of younger granites, rhyolites, and basaltic rocks associated with Jurassic to Tertiary magmatic activity, offering significant economic potential in construction aggregates, dimension stone, and associated mineralisation. This study undertakes a systematic field investigation of volcanic and associated igneous rock occurrences across three localities in Plateau State, with emphasis on petrographic description, geochemical classification, and economic evaluation. Hand specimen and thin section descriptions were conducted to characterise mineral assemblages, textures, and alteration products. Whole-rock major element geochemistry was determined by X-ray fluorescence spectrometry and plotted on standard classification diagrams. Assessment of physical engineering properties including uniaxial compressive strength and Los Angeles abrasion value was performed on selected aggregate samples in accordance with the Nigerian Industrial Standards. The study evaluates the suitability of identified rock types for road construction, building stone, and as host rocks for cassiterite and columbite mineralisation documented in the region. Findings contribute to the mineral resource inventory of Plateau State and support informed decision-making by the Jos Plateau Minerals Development Company. Recommendations for sustainable quarrying practices compatible with environmental regulations are also presented. This research provides an accessible introductory framework for undergraduate geological field investigation of magmatic terrains. Keywords: volcanic rocks, Jos Plateau, petrography, geochemistry, economic geology.