Geotechnical and sedimentological properties of the late quaternary sediments of the Nigerian continental Shelf and Upper Slope, West Africa

Abstract

The growing demand for fossil has been a motivating factor in geological research in Nigeria, West Africa. With estimated oil and gas reserves of 16.5 billion barrels and 34.8 trillion cubic feet, respectively, the Niger Delta is one of the world's richest oil and gas provinces. The growing interest in the hydrocarbon reserves found on the Nigerian continental margin provided the opportunity for Texas A&M University's (TAMLD oceanographic research vessel, the R(V Gyre, to spend August through November 1991 coring and surveying the Nigerian Shelf and Upper Slope. Researchers aboard the Gyre recovered a total of 735 6-m piston cores, 567 of which were included in the sedimentological and geotechnical portion of the TAMU Geochemical and Environmental Research Group's (GERG) Nigerian Shelf and Upper Slope Study. Approximately 10% of the 567 cores were sampled, tested, and evaluated at high resolution spacing. The results of the high resolution core analyses, in conjunction with the subbottom profiles from each of the sites, provided the basis for an evaluation of the significance of the geotechnical and sedimentological properties of the Nigerian Shelf and Upper Slope sediments to the sedimentary processes and sediment distribution observed in the smdy area, particldarly in the region of the Niger Delta. Special consideration was given to the bathymetric and oceanographic conditions observed, hence, establishing a foundation for future sedimentological research in this area. The primary result of the study is a thorough characterization of the study area with respect to the relationships between sediment type and behavior and the environment of deposition based upon the results of the geotechnical and sedimentological testing program. The results of the present study successfijdly corroborated and expanded upon earlier work which focused primarily on the inner shelf region using techniques including index property and grain size determination, bulk and day mineralogical analyses, and consolidation testing. The data available from the 1991 RIV Gyre cruise also permitted making a preliminary assessment of the role of submarine canyons in modern day sediment transport.in the study area and provided a synoptic view of the physical oceanographic factors important in sediment transport.