Preliminary evaluation of major and trace elements content of Cretaceous – Palaeogene Formation of the Sokoto Basin, Northwestern Nigeria

No. of 21 shale, limestone and gypsum samples belonging to the Palaeocene Sokoto Group and 19 sandstone, shale, lignite and gypsum samples from Maastrichtian age the Rima Group of the Sokoto Basin were collected from five traverses across hills and pits, and analyzed for major and trace elements using XRF and AAS analytical techniques. The SiO2/Al2O3 ratio of the Taloka Formation in the Rima Group is high (3.48 21.60 wt%), indicating higher silt contents while in Dukamaje Formation in the same group the ratio is low (4.60 5.9 wt%), indicating lower silt content. The high concentration of Fe2O3 of the Taloka Formation coupled with the lignite occurrence suggests a deposition under a reducing environment. The Dukamaje Formation is generally calcareous shale with gypsum seam/beds which points to marine environment. Major elements in the Palaeocene sediments indicates low silt contents and a tendency towards marine conditions as reflected in its low SiO2/Al2O3 ratio (1.37 5.80 wt%). The higher Fe2O3 content (average > 4 wt%) indicate a reducing environment of deposition. Utilizing the discriminant function diagram for provenance signatures of the sediments using major elements shows that samples of Sokoto Group have intermediate to mafic igneous provenance while the Rima Group sediments have quartzose sedimentary to mafic igneous provenance.