Lithofacies, bounding surfaces and sedimentary architectural elements exposed in two ridges at Uturu being quarried for construction sands were analysed to determine the paleoenvironment of deposition and the factors that control the deposition of sand units. Mainly outcropped is Ajali Formation overlying locally exposed Mamu Formation in Western Afikpo basin. Lithofacies identified include: Trough cross bedded medium- to coarse-grained (St), Planar cross bedded fine- to coarse-grained sandstone (Sp), Small scale planar cross bedded sandstone (SSp), Lenticular mudstone (Fm), Heterolithic sandstone/mudstone (Fsm), Horizontal stratified sandstone (Sh), Cross ripple laminated sandstone (Sr), Reddish muddy sand (Fl), Siltstone (SSm) and Shale (Fsh). The associations of lithofacies and bounding surfaces gave four fluvial and one marine architectural element. The fluvial elements which mainly characterized the Ajali Formation include: Channel-fill (CH), Macroforms Accretion (MA). Flood-Plain Fines (FF) and Channel Abandonment Fines (CAF). Offshore-shoreface fines (OSF) element defined marine Mamu Formation. The profiles of the ridges show dominance of MA followed by CH while FF is limited in occurrence and in some zones pinch-out to lenticular inter-bar mudstone. The MA is characterized by planar cross beddings, reactivation surfaces, internal grading, steep dipping ferruginized accretion surfaces and abrupt flat top which indicate mid-channel bars deposition in typical sandy braided fluvial depositional system. Generally, there is vertical aggradation/ amalgamation of channel deposits and dominance of sheet alluvial architecture. Low rate of channel avulsion, moderate rate of lateral migration and aggradation, variable discharge rate and high rate of sediment supply and subsidence were considered as factors that controlled the deposition and preservations of sand units. This study provided an understanding of mesoscopic heterogeneities and compartmentalization style inherent in hydrocarbon bearing sandy braided reservoirs which can be used as analog model for its development.

Sediment deposition has increased at a meander section of Mbaa river resulting in a drastic reduction of water storage. It has necessitated calls for sand-mining or periodic dredging which could have far-reaching impacts on the aquatic ecosystem, depending on the texture and chemical compositions of the sediment. Therefore, surficial sediments samples were analyzed for textural characteristics, mineralogy and chemical compositions. Grain sizes and mineralogical analysis showed that the sediments were moderately sorted, mesokurtic, near symmetrical - slightly positive skewed, subangular – subrounded medium grained-sands, and consist of about 2.5% feldspar, 2.7% rock fragments, 5.4% hematite and 89% quartz. Mean TOC and pH were 0.39 wt% and 6.48 respectively. Atomic Absorption Spectrophotometer (AAS) analysis results showed general low concentrations of metal elements: mean values of alkali/alkali earth metals ranged from 1.33 - 3.72ppm, transition metals ranged from 0.12 - 23.07ppm; while Pb (a poor metal) was not detected. General low concentrations of metals and TOC; and non-detection of Pb suggest lack of mineralization zones and minimal anthropogenic impacts in the upstream areas.  Textural and chemical characteristics and moderate energy of river water flow suggest that human resuspension of the sediment deposit will result in minimal lateral dispersion of sediment in the water column, except during heavy rainfall. Therefore, periodic dredging or sand mining will cause minimal impact on the aquatic ecosystem, especially in the distant downstream areas, whereas within the meander section and nearby areas of the river, it is expected that there will be a significant change in water quality parameters due to the increase in the concentrations of suspended and dissolved compounds.

Precambrian Pegmatite veins in Igarra were studied and analyzed in order to group the veins based on their structures, orogenic episodes and modal composition. Pegmatite veins are found more in granodiorites, Migmatite-Gneiss and undifferentiated mixed rocks in the study area.  The studied veins were predominantly dykes and sills while some were folded into irregular shapes. Exposed studied veins have minimum length of 2.5m and maximum of 10m.  A minimum width of 43cm and maximum of 2m were also recorded. Structural elements like strike directions analyzed using rose diagrams suggest that the emplacement of pegmatite veins is related to a dominant structural control orogenic event. Two major deformational episodes were recorded on the pegmatite veins studied. The irregular recumbent folded pegmatite veins represent a ductile phase deformation which resulted in the formation of planar structures in the study area. The second deformation that impacted the pegmatites was a brittle phase deformation that resulted to fractures found in basement rocks many which were filled with pegmatites and quartz veins. Results showed that the dominant strike directions of veins were mainly in the NE-SW and N-S directions. Also recorded were few veins which trend in the NW-SE direction both which were likely the imprint of Pan-African orogeny in the study area. Modal composition of minerals from thin section results on samples shows they are predominantly feldspathic pegmatites with k-feldspar between (32 to 46%) with mean value of 40.9% and plagioclase (18 to 30%) with mean value of 21.5%.The NE-SW veins have more biotite than the NW-SE pegmatite veins. Perthitic structures (mask effect of albitic plagioclase) were recorded in the NE-SW veins. Sericitization of feldspars (hydrothermal alteration) was also seen in the NE-SW pegmatite veins. The mineral Tourmaline is associated with NE-SW veins as seen in thin section petrography while Sphene (Titanite) can be found in the NW-SE pegmatite veins.