Agbani Fm

The name “Agbani Sandstone” was used by Murat (1972) and outcrop East of Enugu. The formation has also been studies in wells; Bopo-1, Okpaya-1, Adoka-1, Aiddo-1, Ikem-1, and Amansiodo-1 (Whiteman, 1982). Some publications consider this to be a member of the Awgu Fm; or a formation within an Awgu Gr (as used in South Benue Trough)

Synonym: Agbani Sandstone Fm; Agbani Member of Awgu Fm

References: Reyment, 1965; Adeleye, 1975; Dessauvagie, 1975; Kogbe,1976; Petters, 1978; Offodile, 1980; Whiteman, 1982; Benkhelil, 1989; Okosun, 1992; Guiraud, 1993; Akande et al., 1998; Zaborski et al., 1998; Jauro et al., 2007 ; Obaje,2009; Nwajide, 2013

[Fig. 1. Stratigraphic successions in the Benue Trough and the Nigerian sector of the Chad Basin]

[Fig. 2. Sedimentary Basins of Nigeria (Obaje, 2009)]

[Fig. 3. Stratigraphic packaging in the Southern Benue Trough (based on Reynment, 1965; Murat, 1972; Whiteman, 1982)]

The lithofacies are mainly white, medium to coarse, pebbly (quartz and clay chips), poorly sorted sandstone occurring above the Awgu Shale. The thickness of the Agbani Fm is about 40m in the subsurface, as noted in well Adoka-1 (Agagu et al., 1985). There are interbeds of brown laminated clays and carbonaceous shales. Large-scale planar cross-beds are present, and locally show westerly dips up to 20°. In the Otukpo area, the sands are finer and better sorted. There are also interbeds of dark grey micaceous, calcareous, pyritic shales.

Fluviatile – deltaic depositional environment which consists of arenaceous component of the Santonian fluvial clastic influx that terminated during the Coniacian–Santonian marine sedimentation documented by the Awgu Fm. Thus, the Awgu Fm in the subsurface could be the prodelta of the Agbani Delta (Agagu et al., 1985).