Biostratigraphy and Paleoenvironmental Interpretation of the Eyasi-Wembere Rift Basin, Tanzania: Implications for Hydrocarbon Potential

We present biostratigraphic findings from three shallow stratigraphic boreholes (Nyalanja-1, Kininginila-1, and Luono-1) drilled in the Eyasi-Wembere Basin. Rift Basin. Ninety (90) s amples were analyzed using the standard palynological and micropaleontological methods. The samples yielded fair to well-preserved terrestrial palynomorphs and ostracods except samples from the Kininginila-1 borehole, which were mostly barren. Based on documented palynological and ostracod assemblages, Pliocene to Holocene age is inferred in Njalanja-1 and Luono-1 boreholes. A shallow lake environment, with intermittent periods of lake expansion during the wet season, characterizes the deposition environment. This is further supported by the higher abundance of ostracods (Candona spp.) observed in deeper intervals of the Njalanja-1 borehole. The hydrocarbon potential assessment especially in the Njalanja-1 borehole revealed a high abundance of amorphous organic matter (kerogen type I/II) capable of producing oil. The source rock is marginally mature.