113-2 Compositional Features of Ironstone Occurrences around Amore-Idiayin area, Ise Formation, Dahomey Basin, Southwestern Nigeria

Session: Mineralogical Characterization of Economic Resources: From Critical Minerals to Gemstones (Posters)

Poster Booth No.: 247

Presenting Author:

Innocent OFIA

Authors:

OFIA, Innocent Chinedu¹, OKUNLOLA, Olugbenga Adedeji²

(1) Department of Geology, University of Ibadan, Ibadan, Oyo State, Nigeria; Siberia school of Geoscience, Irkutsk National Research Technical University, Irkutsk, Irkutsk, Russia, (2) Department of Geology, University of Ibadan, Ibadan, Oyo State, Nigeria,

Abstract:

The study investigates the mineralogical and geochemical characteristics of ironstone occurrences in the Idi-Ayin area, located within the Ise Formation of the Dahomey Basin, southwestern Nigeria. Iron, being a crucial industrial metal, necessitates detailed exploration to enhance Nigeria's economic development and industrialization efforts. Despite extensive research on ironstone deposits in other Nigerian basins, the Dahomey Basin remains underexplored.   Fieldwork involved reconnaissance, systematic sampling, and petrographic analyses. Twenty ironstone samples were collected and analyzed using X-ray Diffraction (XRD), X-ray Fluorescence (XRF), and Scanning Electron Microscopy (SEM) to determine mineral composition and geochemical properties. Results indicate that the ironstones predominantly comprise goethite, hematite, and magnetite, with significant silica and alumina content. The SiO₂ content varies between 9.08% and 23.53%, while Fe₂O₃ ranges from 56% to 73.83%, suggesting a high iron concentration with potential economic viability.   The geochemical data reveal that the ironstones are Oolitic and pisolitic with oolitic dominating, this indicates deposition in a high-energy, shallow marine environment. The Al₂O₃-SiO₂-Fe₂O₃ triangular plot suggests a diagenetic origin, while elemental variation indicate lateritization and extensive ferruginization. The study also compares the geochemical characteristics of the Idi-Ayin ironstones with other Nigerian and global ironstone deposits, confirming their significant iron enrichment and economic potential.The oolitic ironstone showed high iron content and very low deleterious components, which makes suitable for steel production. This research provides critical insights into the genesis, composition, and economic feasibility of ironstone deposits in the Dahomey Basin. Findings contribute to Nigeria’s mineral resource development strategies and support industrial applications in steel production.   Keywords: Ironstone, Dahomey Basin, Geochemistry, Mineralogy, Ise Formation, Economic Feasibility

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

doi: 10.1130/abs/2025AM-4382

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