BASEMENT CONFIGURATION OF THE NOSSOP-NCOJANE BASINS,NW BOTSWANA, USING GRAVITY AND MAGNETIC DATA

The Nossop - Ncojane sedimentary basins (NCB), located in southwestern Botswana, form part of a suite of several sub-basins that comprise the Neoproterozoic Nama Basin (NB). The NCB were first discovered during a reconnaissance aeromagnetic survey in the late 1970s as magnetic minima occur over >15 km of sedimentary rocks. Since their discovery, the NCB have been the focus of several hydrocarbon exploration exercises with no success. The tectonic origin of the basins is thought to be orogenic collision forming a foreland basin based on limited geological and geophysical analyzes. Thus, the exact origin of the basin is under question. The aim of the current study is to determine the basin configuration of the NCB, and to the map basement structures associated with the basins. The Nossop basin is characterized by 93 nT and 14 mGal negative magnetic and gravity anomalies, respectively, and has a surface area of 21,000 km². On the other hand, the 12,800 km² Ncojane basin is characterized by a 283 nT negative magnetic anomaly and a 5 mGal positive anomaly. The Moho depths beneath both basins range from 32-40 km. These basins will be analyzed by enhancing the gravity and magnetic fields over both of the basins. decompensative and isostatic residual gravity anomaly fields will be used to map the extent of the basins and structures associated with them. Euler deconvolution and 2D forward modeling will be used in the analysis ot the depth extent of the basin and aid in determining a tectonic origin of the basin.