Application of Potential Field Data for Mapping and Delineating Geological Structural Trends of the Rufiji Depression and Its Vicinity for Hydrocarbon Exploration, Tanzania

Abstract

Rufiji Depression covers mainly the Rufiji River in the southeast of Tanzania. It is one of the coast basins of Tanzania formed during the rifting events of both the failed Karoo I in the west and successful Karoo II in the east with sediments deposition from Permian to Jurassic period. This study intended at mapping and delineating geological structural trends in this region, where potential field data were utilized. The first vertical derivative (1VDR), tilt derivative (TDR) and total horizontal derivative (THD) enhancement methods were applied to the reduction to pole of the total magnetic intensity (RTP-TMI), while the 1VDR and TDR methods were applied to gravity data. After the enhancement methods to the potential field data, the geological structural trends related to regional faults with major trends: W – E, NNW – SSE, NNE – SWW, NNW – SSE and NNE –SSW were identified and delineated. Also, some new structural trends in the Massasi Spur Basement and probably Neogene structures from gravity data were detected. The regional depth to basement was computed using Power spectrum and Standard Euler Deconvolution method for magnetic and gravity data respectively. With these methods, the depth to basement was estimated in the range of (2.3 ± 0.8 – 10.5 ± 0.8) km, across the study area. Comparison of the results with other geological studies conducted across the coast basins of Tanzania indicated good correlation. Generally, the confirmed existence of structural trends in the Rufiji Depression and its vicinity controls the deposition of sediments and acts as hydrocarbon migration pathways in this region.