Prosopsis Fm

Mango Depression in the central-southern parts of the basin

Bongor Basin (SW Chad).

Reference: Chen et al., 2018; Wang et al., 2022; Dou et al., 2023

[Fig. 2: Stratigraphic chart for the Bongor Basin showing the positions of producing reservoirs, source rocks and seals (from Dou et al., 2020)]

[Fig. 1: Simplified map of the West and Central African Rift System (WCARS) showing the major features discussed in the text and the location of the Melut Basin in South Sudan (modified from Genik, 1993)]

The Prosopsis Fm is made up of dark grey mudstones interbedded with thin- to thick-bedded, fine- to coarse-grained sandstones and conglomerates (Chen et al., 2018; Wang et al., 2022). On the basis of seismic interpretation, the maximum thickness of the Prosopsis Formation in the Mango Depression in the central-southern part of the basin is 3500 m, while drilling reveals that it is relatively thin in the Northern Slope (<1500 m) (Dou et al., 2023). The lower member contains a large set of sandstone primarily, with a basal conglomerate developed at the edge of the basin while the upper member is composed of mudstone intercalated with sandstone layers (Dou et al., 2023).

ostracod (Bisulcocypris, Lycopterocypris, cf. Bisulcocypris lubimova, B. defense, B. cf. defensum, Cypridea cf. prognata, C. cf. subconcina, Triangulicypris cf. longissima, Darwinula leguminella and Mantelliana sp..), Pollens (Classopollis, Cicatricosisporites, Callialasporites, Dicheropollis, ),

Valanginian

Fan Delta – subaqueous fan – deep to semi-deep lake (Chen et al., 2018; Wang et al., 2022).