Patti Fm

Reference section: 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 Mid-Niger Basin (also known as Bida or Nupe Basin)]

with occasional soft sedimentary structures (e.g. slumps), and other structures such as wave ripples, convolute laminations, load structures. Trace fossils (especially Thallasanoides) are frequently preserved. Interbedded claystones are generally massive and kaolinitic, whereas the interbedded grey shales are frequently carbonaceous. This formation consists of fine to medium, grey to white sandstones, carbonaceous silts and shales and oolitic ironstones (Jones, 1958). There are thin coal seams and massive, white sandy clays are common. Overall, the maximum exposed thickness is about 70m which thins out completely northwards (Nwajide, 2013). The abundance of woody and plant materials comprising mostly land-derived organic matter, suggestsprevailing fresh water conditions. However, biostratigraphic and paleoecologic studies by Petters (1986) have revealed the occurrence of arenaceous foraminifera in the shales of the Patti Formation with an assemblage of Ammobaculites, Milliamina, Trochaminaand Textularia(Fig. 7.3) which are essentially cosmopolitanmarsh species similar to those reported in the Lower Maastrichtian marginal marineMamu Formation (the lateral equivalent) in the adjacent Anambra Basin (Gebhardt,1998).