207-6 Remote Sensing, Geophysical, and Geochemical Datasets Assessment of Li-Bearing Pegmatites at Ewoyaa, Southern Ghana

Session: Honoring the Late Professor Mohamed Abdelsalam: Outstanding Researcher, Generous Colleague, Legendary Mentor, and Ambassador for the Geosciences In Africa

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Abstract:

As the global shift towards cleaner energy sources accelerates, the demand for lithium for rechargeable batteries—essential for electric vehicles, laptops, and mobile phones—continues to rise. Ghana’s Ewoyaa lithium deposit, with ore reserves of 25.6 million tons and an expected operational lifespan of 12.5 years, is projected to begin production in the second quarter of 2025. This deposit lies within the Cape Coast Basin, a Proterozoic volcano-sedimentary basin, which is part of the Early Proterozoic Birimian Supergroup. The region features metasedimentary sequences intruded by granitoids, consisting of tonalite to peraluminous granite and subvertical pegmatite dikes with mineralized units ranging from 30 to 100 m thick.

This study integrates remote sensing, geophysical, geochemical, and geological datasets to map mineralized lithium-bearing pegmatites from the surrounding rocks. High-resolution WorldView-3 and ASTER imagery, along with drone imagery at 10 cm pixel resolution, are used for spectral analysis to evaluate their effectiveness in mapping spodumene-bearing pegmatites and associated hydrothermal alteration zones. Airborne magnetic and radiometric datasets are analyzed using upward continuation, derivative filtering, and Euler deconvolution to interpret the geology and geological structural patterns contributing to the potential mineralized zones. The magnetic data show a low magnetic response in the area of interest, which is likely due to hydrothermal alteration or non-magnetic pegmatites. In contrast, the radiometric K/Th ratio shows moderate to high values, suggesting potassic alteration, which is typically associated with pegmatite formation and lithium mineralization. These anomalies point to the presence of possible structural controls, which could guide future investigations for lithium-bearing pegmatites.

To validate the mapped anomalies and improve exploration targets, geochemical data from rock and soil samples, as well as drill hole data, are examined. Elemental concentrations were determined using both Laser-Induced Breakdown Spectroscopy (LIBS) and portable X-ray fluorescence (pXRF), resulting in a full multi-element geochemical profile that includes lithium and other pathfinder elements.

In order to enhance the accuracy of target detection, machine learning techniques are used to interpret the multi-source datasets, offering a data-driven approach to lithium exploration in the Ewoyaa region.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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