Gongila Fm

This section of the Gongola Arm was divided: the Lower sequence is the Gongila Fm and the Upper Sequence is the Pindiga Fm. The type locality of the Gongila Formation is at the Quarry of the Ashaka Cement Company at Ashaka, while that of Pindiga Fm is at Pindiga village.

References: Falconer, 1911; Carter et al., 1963; Reyment,1965; Adeleye,1975; Kogbe,1976; Dessauvagie, 1975; Petters, 1978; Offodile, 1980; Whiteman, 1982; Avbovbo et al., 1986; Benkhelil, 1989; Okosun, 1992; Guiraud, 1993; Akandeet al., 1998; Zaborskiet al., 1998; Jauroet al., 2007; Obaje,2009; Nwajide, 2013

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

Lithologically, these formations (Gongila Fm and Pindiga Fm) are characterized by the dark/black carbonaceous shales and limestones, intercalating with pale colored limestones, shales and minor sandstones. The Gongila Fm is composed of thin to moderately thick interbeds of calcareous gray to dark shales and silty sandstones deposited in a shallow-marine environment and said to be a rough equivalent of the Yolde Fm in the Northern Benue Trough by Carter et al. (1963). The limestones near the base of this sequence include non-fossiliferous and shelly limestones and rather impure limestones which contains numerous ammonites. Although no certain thickness has been established for this formation, Okosun (2013) estimated the thickness to be about 1,200m using the log from the Kanadi-1 well. In Benue Trough North, it is also reported that the Gongila Fm has an average thickness ranging from 100 to 150meters and the Pindiga Fm average about 300 to 500 meters.