| Hydrocarbon potential of the passive continental margin of Tanzania has been influenced by sea level changes, tectonics, and climate, all of which had an impact on the deposition of sediments in the area. Previous work had concluded that the region has lean terrestrial source rocks with no potential for the generation of commercial liquid hydrocarbons; however, investigations by the author indicate that potential Jurassic marine source rocks were deposited in the area. The deposition of potential source, reservoir, and cap rock sediments has been influenced by the interaction of eustasy, subsidence, and climate. The potential source rocks and seals are deposited as transgressive systems. Potential reservoir rocks are deposited as highstand and lowstand systems. The deposition of Bajocian and Bathonian potential source rocks can be traced to a transgressive system associated with the opening of the Indian Ocean during the fragmentation of the southeastern Gondwanaland. Transgressive surfaces and condensed sequences, such as Posidonia shales and marls in the upper Jurassic, are associated with potential source rocks. The Neocomian lowstand of sea level has influenced the deposition of basinal fans and slope fans that are potential reservoir rocks. The transgressive shales of the upper Cretaceous constitute a potential seal. Modelling of the upper Cretaceous sequence indicates high rates of deposition that may have partly influenced the development of overpressuring. |
