LITHOFACIES ANALYSIS AND HEAVY MINERAL ANALYSIS OF THE EBENEBE SANDSTONE OF THE IMO FORMATION IN ISIAGU, SOUTHEAST NIGERIA

ABSTRACT This study investigates the lithofacies characteristics and heavy mineral composition of the Ebenebe Sandstone of the Imo Formation, southeastern Nigeria, with the aim of reconstructing its depositional environment, provenance, sediment maturity and tectono-sedimentary setting. Detailed field geological mapping and lithologic description were carried out, followed by laboratory-based geochemical and heavy mineral analyses of representative sandstone samples. Lithofacies analysis shows that the Ebenebe Sandstone is dominated by medium- to coarse-grained massive and cross-bedded sandstone facies, with subordinate fine-grained sandstone and shale interbeds. The vertical facies arrangement displays an overall upward coarsening trend, which is characteristic of a progradational deltaic to shallow marine depositional system. These lithofacies associations indicate deposition under high-energy hydrodynamic conditions, controlled by wave, tidal and current processes. Heavy mineral and geochemical analysis of sample LE 1B reveals a very high silica content (SiO₂ ≈ 97.65 wt%), indicating a quartz-rich sandstone. Elevated Zr, Hf and TiO₂ concentrations indicate dominance of ultra-stable heavy minerals such as zircon and rutile, while high Cr and V values suggest a minor contribution from mafic source rocks. These geochemical signatures indicate a mixed felsic–mafic provenance and a high degree of mineralogical maturity. The dominance of quartz and ultra-stable heavy minerals suggests that the sediments experienced intense chemical weathering, long-distance transport and repeated hydraulic reworking prior to final deposition. The Integrated lithofacies and heavy mineral data indicate that the Ebenebe Sandstone was deposited in a high-energy shallow marine to delta-front environment within a passive margin to post-orogenic tectonic setting. This study provides valuable insights into the sedimentological evolution of the Imo Formation and contributes to the understanding of sandstone provenance, depositional processes and reservoir potential in southeastern Nigeria.