Geophysical study of the subsurface structures of the Rufiji basin, Tanzania

This study presents detailed results of subsurface investigation of the Rufiji basin, which is one of the onshore coastal sedimentary basins in Tanzania. Despite limited number of geological and geophysical research works that have been conducted in the area, there is limited information about the structures controlling the basin and the spatial variations of sediments thickness. This study aims to delineate the subsurface geological structures controlling the basin, establish the spatial variations of sediments thickness and link between structures and the basin configuration. The results from different techniques have been obtained by combining gravity, magnetic, SRTM-DEM and geological field structural data where, Oasis Montaj, ArcGIS, Polar plots and Win tensor software’s were used to process, enhance and model the data to produce maps and Rose diagrams. Four distinct structural trends have been distinguished: the dominant were NE-SW and NW-SE, less structural trends were E-W and NNW-SSE. Gravity and Magnetic data unveiled mainly normal faults in the basin. The structural sets are mainly basement inherited and some of the trends influence the general trend and/or configuration of the basin itself. Presence of faults system and other lineaments in the basin provide a good chance to form hydrocarbon prospect. Depth estimations obtained from located Euler deconvolution, spectral analysis and modelling of the profiles indicates that the basin has a range of depth between ˂1 km to 12.78 km with the maximum depth being in the NW, SW, N and NE parts of the basin. Estimated depth from three methods suggest adequate burial depth to allow maturation of hydrocarbon. Furthermore the basin is potential for hydrocarbon exploration.