Paleo Depositional Environment of the Tertiary Urue- Offong/ Oruko Sandstone Deposit, Akwa Ibom State, Nigeria

This research investigates the paleoenvironmental conditions of the Urue-Offong/Oruko Sandstone deposit through detailed grain size analysis and pebble morphometry. A comprehensive sampling strategy was employed, collecting sediment and pebble samples from various locations within the deposit and a total of 55 sandstone samples were collected across the study area. The grain size distribution was analyzed using sieve analysis, while pebble morphology was assessed through morphometric measurements, including elongation ratio, flatness ratio, and roundness. Results indicate that the sediments are predominantly medium- grained and well-sorted, exhibiting a skewness towards finer particles, which suggests a fluvial depositional environment. The pebble morphometric parameters reveal a dominance of compact- bladed and elongate shapes, with significant roundness values indicating moderate transport distances. Bivariate plots further support these findings by correlating roundness with elongation ratios and sphericity indices. The integration of these analyses provides insights into the sedimentary processes that shaped the Urue-Offong/Oruko Sandstone deposit, highlighting its formation in a dynamic fluvial setting. This study contributes to the understanding of the geological history of Akwa Ibom State and offers methodologies for future paleoenvironmental reconstructions in similar geological contexts. Keywords: Paleoenvironmental reconstruction, Urue-Offong/Oruko Sandstone, Grain statistical parameters, grain size analysis, pebble morphology, Akwa Ibom State.