Analyzing Sedimentary Rocks to Determine Hydrodynamic Conditions of Anambra Basin, South-Eastern Nigeria

Abstract

The Anambra Basin in southeastern Nigeria is a notable sedimentary basin with a complex geological history shaped by marine, fluvial, and deltaic processes. This study examines the sedimentary rock formations within the basin, focusing on the Nkporo, Mamu, Ajali, and Nsukka Formations. The main goal is to reconstruct past hydrodynamic conditions and sediment transport mechanisms that influenced sediment deposition. Using a combination of field observations and quantitative methods, we estimated key paleohydrodynamic parameters such as channel depth, bedform height, sediment transport modes, and flow velocities. Analyzing these parameters provides insights into the ancient environmental conditions during deposition. Our findings reveal diverse depositional environments in the Anambra Basin. The Nsukka Formation is linked to transitional flow conditions with moderate sediment suspension, indicating a balance between transport and settling. In contrast, the Ajali Formation reflects a stable environment dominated by bed load transport, suggesting consistent flow. The Mamu Formation indicates dynamic and turbulent flow conditions that facilitated both bed load and suspended sediment transport. Additionally, the Owelli Sandstone Formation shows transitional flow characteristics typical of coastal or shallow marine environments influenced by both marine and continental processes. This study enhances our understanding of sedimentary processes in the Anambra Basin and lays a foundation for future research on its geological history and sedimentary dynamics.

Keywords

• deposition
• environments
• formations
• quantitative
• sediments