DEPARTMENT OF GEOLOGY

The study incorporates inorganic geochemistry for a comprehensive stratigraphic analysis. To further elucidate sediment provenance, paleo-redox conditions, tectonic settings, and sandstone classification, ditch cutting samples were collected from the Osedestiny well in the Niger Delta Basin. The geochemical results revealed trace element ratios of V/Cr and U/Th, suggesting an oxic environment for deposition. The sediments' source was identified as felsic rock through bivariate plots of Ni vs Tio2, La/Sc vs Th/Co, and trace elemental ratios including Th/Sc, Th/Co, Cr/Th, and La/Sc. Graphical representations of K2O/Na2O versus SiO2 and Log (K2O/Na2O) versus Log (SiO2/Al2O3) predominantly fell within the passive margin zone. Various chemical sandstone classification systems classified the sediments as sublitharenite, Fe-rich sand, and with minimal content of quartzarenite. This comprehensive geochemical approach enhances the understanding of sediment characteristics and depositional environments in the Niger Delta Basin.

Geochemical and mineralogical determination of clay deposits with
integrated sedimentological characterization of their physical properties are fundamental in bridging the knowledge gap and raw material feed for industrial processes and applications. In this study, I investigated clays at locations with relatively little or no investigations carried out to discover the untapped mineral deposits. The clay deposits situated at Iguoriakhi, Ofunmwengbe and environs were investigated using several analytical techniques; X Ray Diffractometry (XRD), X Ray Fluorescence Spectroscopy (XRF), Hydrometer Method, Wet Sieving Analysis and other geotechnical techniques. The average abundance of minerals in the samples derived from the XRD Peaks indicates that Clay minerals present include; Kaolinite, ranges between (19.52% - 22.33%) and (24.24% - 28.60%), Montmorillonite (10.49% and 4.6%), Illite (5.24% and 4.07%) and associated non clay minerals include; Mica (5.50% - 7.02%) and (4.88% - 6.03%), Feldspar (6.02% - 6.53%) and (3.03% - 3.50%), quartz (49.77% - 52.80%) and (54.11.0% - 55.99%) for Iguoriakhi and Ofunmwengbe samples respectively. Geochemical signatures Al2O3/TiO2 ratio for clastic rocks used to determine origin indicates that the Al2O3/TiO2 for Iguoriakhi and Ofunmwengbe clays range between (23.73 – 50.40) and (22.92 – 51.88) respectively signifying that the clays originated from
intermediate to felsic igneous rocks. The high Chemical Index of
Alteration (CIA) ranges between 86.14 - 93.57 and 86.05-93.47, Chemical Index of Weathering (CIW) between 93.59 - 97.71 and 93.55
- 97.67 and Weathering Index of Parker (WIP) between 10.27 - 12.02
and 10.04 - 12.1.

There has recently been an increase for the usage of clay minerals. Hence, the driving force for this research work which was carried out to determine the chemical composition and basic geotechnical and physical characteristics of Ogiso and Okhoro clay deposits in Edo State, Southern Nigeria. In this study, ten (10) fresh clay samples were randomly collected, three(3) from Okhoro and seven(7) from Ogiso and were subjected to X-ray-Diffraction (XRD), Xray-Fluorescence (XRF) and geotechnical analysis to determine their mineralogy, chemical composition and engineering behaviour so as to evaluate their economic potential. The XRD analysis revealed that the basic mineralogy of the samples studied is made up of kaolinite, quartz and hematite with traces of zircon, illite and anatase occurring in minor amounts in some of the samples. The XRF analysis revealed the occurrence of 10 elemental oxides and 10 elemental trace elements. The major elemental oxides include SiO2 with a range of 55.82 – 61.41wt %, Al2O3 with a range of 21.12 – 24.42% and Fe2O3 with a range of 6.05 – 9.06% while the major elemental trace elements are zircon with a range of 0.89 – 1.78wt%, zinc with a range of 0 – 1.51%, copper with a range of 0 – 1.39wt% and chromium with a range of
0.01 – 0.11wt%. The geotechnical analysis revealed that the samples are of low to medium plastic inorganic clay with percentage fines fraction of 76.84 – 78.45%

Twenty-two samples were collected from Egboha well in Imo Formation, from which ten(10) samples were used to identify the different lithologies, Degree of effervescence were carried out to determine samples with carbonate minerals. Geochemical analyses were also carried out to get the geochemical data using ICP-MS and ICP-OES. Geochemical data for Imo Formation are presented and applied as proxies for deciphering paleo-environment (detrital influx, redox conditions, paleo-productivity) and providing insight to paleo-environmental conditions responsible for sedimentary geochemistry of Imo Formation. The detrital influx proxies used for this work [Si/Al having values ranging from (5.386-2.976) and Ti/Al having values ranging from (0.099-0.061)], show an increase in detrital influx (rate of deposition) and coarse grain at two depths, and at the other depths there is a decrease in detrital influx and fine grain. Paleo-redox proxies used for this work [Mo/Al having values ranging from (0.539-2.429), Ni/Al having values ranging from (7.181-16.194), U/Al having values ranging from (0.467-2.065)], show an enrichment of (U, Mo, Ni) and the oxygen level being suboxic - anoxic environment. Paleo-productivity proxies [Ba/Al having values ranging from (43.088-27.935)] shows an increase in the paleo- productivity at three depths which indicates high productivity of organisms during the Paleocene period, while at other depths, low productivity of organisms can be observed. Paleo-salinity [Sr/Ba having values ranging from (0.065-0.112)] shows an increase in paleo-salinity, which indicates high salt content at two depths and at other depths low paleo-salinity can be observed at
other depths. The result shows that elemental geochemistry can be applied to Study the paleo environment, paleoclimate, and depositional conditions

The extent of groundwater and soil pollution arising from an open dumpsite was carried out to examine the physico-chemical and trace metals status in Osubi, Delta State. Twenty two (22) soil samples were collected randomly at depths of 0-15 cm, and 15-30 cm and one control (natural environment). While sixteen (16) groundwater samples were collected through random sampling technique for analysis. The soil samples were digested into solution using aqua regia and analyzed using the Atomic Absorption Spectrometer (AAS), [buck model 210 VGP]. The results of the analysis was then subjected to statistical treatment (One-way Analysis of Variance), Spearman’s Correlation Coefficient and Pollution Load Index to ascertain significant difference among the trace metals, association and status of contamination/pollution respectively. Result from the analysis showed that both groundwater and soil samples in the study area is acidic with pH values ranging from 5.28-5.96, and 2.30-6.20 respectively. The level of average metal contents obtained from soil samples at the different depths is as follows: Arsenic; 10.58-20.4 mg/kg, Manganese; 1.42-3.58 mg/kg, cadmium; 1.05-3.46 mg/kg, Chromium; 1.61-4.55 mg/kg, Lead; 2.11-3.71 mg/kg, Zinc; 5.77-15.5 mg/kg, Copper; 1.69-3.23 mg/kg, Cyanide; 0-0.005 mg/kg, Nickel; 1.31-4.59 mg/kg and Vanadium; 1.24-0.3.95 mg/kg which were much higher than that of the control. The correlation result between the analyzed parameters in hand-dug wells and borehole samples, revealed positive and negative correlation coefficients at r(0.01) and r(0.05) indicating strong association between them, which probably reflects their related source of contamination. However, correlation was also not significant among some parameters in the groundwater samples indicating an uncommon source of contamination. Calculated pollution load index (PLI) indicated that location SS8 had maximum pollution load index of 2.15 and a minimum pollution load index value of 1.80 was obtained at location SS6. The order of pollution load index per location for the sediments is as follows: SS8 > SS5 > SS9 > (SS4=SS7=SS10) > SS2 > SS3 > SS6. While the order of contamination factor (CF) revealed among the heavy metals is as follows: Mn> V > Cr > Ni > Cd > Zn > As >Pb> Cu. The results revealed that both the groundwater and soil were slightly- moderately contaminated. It is hereby reco mended that groundwater monitoring and proactive steps be taken to minimize gradual accumulation of these contaminants from the dumpsite.

The research looked at the sedimentary process and the exact period of environmental deposition in the imo formation. From the thirty-two (32) ditch cutting samples that were collected and processed, twelve (12) samples were forwarded to the Activation Laboratory for geochemical analysis with the aid of the Ultratrace 7 package. The sample was taken from a depth interval of 1060 feet (1,060 meters) at the Obaretin Well in Nigeria's Benin flanks, where it undergone a complete geochemical study. Twelve samples were taken, and they underwent an effervescence test using diluted hydrochloric acid (Hcl). On the sample, carbonate was detectable. There was some strong (3), moderate (2), and weak (1) effervescence notices. Applying the aforementioned elemental proxies, such as trace, major, rare element the following was determined: grain size, paleosalinity, paleoproductivity, and paleooxygenation. For the grain size, silicon and aluminum, (Si/Al), when silicon increase the aluminium decrease the grain size from sample was coaser and larger in size. While strontium and barium (Sr/Ba) were the proxies used for paleosalinity, the trend line shows that higher salinities created marine environments, while lower salinities create river channels. A decline in paleoproductivity results in a low input of terrigenous material, whereas an increase in paleoproductivity results in deposits of rich terrigenous material. Barium and aluminum (Ba/Al) were utilized as proxies in the paleoproductivity study. Oxic, suboxic, and anoxic environments are the core topics of paleo oxygenation. Numerous elemental proxies, such as Molybdenum and Vanadium (Mo/V), were employed. Environment quality is determined by paleooxygenation. This study has helped in understanding fully about the sedimentary processes and depositional environment.

Warri and its environs have been recently challenged with incidences/imminence of building collapse with frequency of four incidences in the past four (4) years. Hence, geophysical, geotechnical and mineralogical investigations were conducted in an area of failed building and other areas in Warri with a view to comparatively analyse the geotechnical and mineralogical properties of subsurface soils for future building and road developments in Warri. This involved the drilling of ten (10) boreholes in the failed area and fifteen (15) holes in other areas which were all complimented with twenty five (25) Cone Penetration Tests. Samples from boreholes were subjected to geotechnical index/foundation analyses and X-ray Diffraction analyses (XRD). Geophysical and geotechnical investigations showed that the failed area had a laterally heterogeneous two-three layer soil profile which from top to bottom consisted of sandy silt/silty sand (3m thick), clayey silt (15-17m thick) and fine-medium grained sands (2m thick). This was at variance with the other areas which had a relatively homogeneous three layer soil profile which from top to bottom consisted of loose sandy humus top soil (0.25m thick), reddish brown silty sand and fine to medium grained sands (3-8m thick). Classification characteristics using the American Association of State and Highway Transport Officials (AASHTO) showed that the superficial soils in the failed area were mainly of A-7, A-6 and A-4 characteristics with California Bearing Ratio (CBR of 3-20.5%, average: 6.25%) indicating they are competent subgrade materials but incompetent sub-base and base course materials for road construction. Similar characterization in other areas reflected soils of A-2, A-6 and A-3 characteristics with CBR (10-17.9%, average: 15.02%) indicating similar competence and deficiency to that of the failed area. Sand stabilization increased the subgrade quality of the superficial soils in both areas. Cement and composite stabilization improved all soils to sub-base and base quality materials respectively. Foundation studies showed that superficial soils in the failed area are of lower foundation quality (bearing capacity of 184-229kpa, compression indices; 0.12-0.62) than the other areas (bearing capacity of 185-575kpa, compressibility indices; 0.31-0.34). Superficial soil mineralogy showed that the failed area consisted of quartz (75.33-94.20%), kaolinite (5.79- 11.99%), smectite, muscovite and microcline which is consistent with the other areas except for the absence smectite. This showed that structural failure in the challenged area was due to soil lateral variation and poor foundation quality.

This research is focused on the sedimentological characterization and petrographic analysis of a sedimentary outlier unit at the outskirts of Ikpeshi area. The sedimentological study of sections of the rock units involved the description, measurements and sampling of various sections and samples broken off from the rock unit in situ. The laboratory studies carried out in this research include petrographic analysis involving thin section petrography. This rock unit occurs as boulders on a narrow ridge and they are
surrounded by basement complex rocks, they have a coarse texture, and contain particle size that range from about 1mm – 15mm with a dominant clast size of 2mm, they are poorly sorted and they range from sub-angular to angular in roundness. They contain about 85% quartz, 10% clay minerals and lithic fragments account for the rest. The rock unit was observed to be texturally and mineralogically immature. These rock units have been established as sandstones, made up of very coarse sands – small pebbles mineral grains, they are sub-arkosic in nature which is a function of the percentage of the mineral content and the lithic fragments. The sandstone unit consists of series of sedimentary structures which include cross beds, which formed as a result of sudden rise and fall in the depositional energy, the direction of dips of these cross beds indicates the paleocurrent direction of the transporting medium at the time of deposition. The rock unit outcrops in the Benin flank, the sandstone is described as
Pre-Santonian due to its age, the sandstone is observed to be older than sandstones that were formed in the Anambra Basin. This is evident in the compaction difference or diagenetic process that occurred between the two, the sediments as well as the depositional processes that make up these sandstones is suggested to have come from the lower Benue Trough this can be said to be true as a result of 2 the clear distinct lithological and textural characteristics of the sandstones formed in Anambra Basin and the sandstones that is been examined.

Soil, surface water and groundwater samples were collected for physico-chemical, microbial and heavy metal analysis from different locations in Ologbo and environs. Thirteen (13) soil samples including Three controls (Pristine environment) were randomly collected at subsurface depth of 0-30cm, Thirteen surface water samples were collected including three controls and Ten (10) Groundwater samples were collected using random sampling Technique. The samples were collected in order to evaluate the level of pollution/Contamination of the media as a result of petroleum activities, wood industries and other anthropogenic activities within the study area. The results for the groundwater analysis showed pH (5.61-5-78), EC (54.64-65.74), Turbidity (0.05-0.12NTU), Cu (0.38-0.49mg/l), Zn (0.3-0.39mg/l), Cr (0.09-0.16mg/l), Ni (0.64-0.85mg/l), Fe (0.38 2.49mg/l), Mn (0.1-0.15mg/l and Pb (0.01-0.16mg/l). The results for the surface water showed pH (5.71-6.05), turbidity (7.31-13.92NTU), EC (87.11-95.2uS/cm), Zn (0.41-0.45mg/l), Fe (1.24-1.3mg/l), Cu (0.51-0.54mg/l), Cr (0.35-0.38mg/l), Ni (0.09-0.21mg/l) and Pb (0.02- 0.06). These results were compared with world and national standards, and control samples were
collected and used for comparison where needed .The result, of the analyses were further subjected to statistical treatment such as Spearman’s correlation Co-efficient, ANOVA and concentration Factor Analysis, to ultimately ascertain the spatial relationship between sample. The ANOVA results for soil samples indicated a very strong significant difference at (p<0.01)
between control and soil samples for all parameters. Correlation results revealed positive and negative correlation Co-efficient at r (0.01) and r (0.05) indicating strong relationship between them, which probably reflects their source of Contamination. Concentration maps generated for the area showed high concentrations of Lead, Copper and Iron around the central area, increasing towards the southwestern part of the maps. The groundwater flow map showed a 2-way flow direction towards the central part where the major river dividing the map is located. The overall results revealed moderate contamination/pollution of all varieties of samples analyzed and it’s here by recommended that important steps be taken to minimize the negative effects of oil exploration and wood industries in Ologbo.

One hundred (100) ditch cutting samples from OK-1 well, Greater Ughelli Depobelt, Niger Delta Basin, Southern Nigeria, collected from Research and Development Division of Shell Petroleum Development Company was subjected to lithological analysis with the aim of identifying the lithofacies, lithozones, source rocks and seal or caprocks of the analyzed section of the well. The lithological analysis was carried out between six thousand, one hundred and forty (6140ft) and twelve thousand, seven hundred and forty (12740ft). Various lithofacies, together with their associated mineral units were observed mainly by visual examination, aking note of grain sizes, shapes, color, sorting patterns, presence of plant materials and lignitemstreaks of the samples provided. Results of the lithological analysis yielded two (2) lithofacies, which include shale and sandy shale, with presence of plant materials and streaks of lignite, and as a result six (6) lithozones were established. All the lithofacies within the analyzed section of The well were regarded as potential source rocks, because they satisfied the lithological characteristics of source rocks. Seal or caprocks potential of the analyzed section could not however be totally ascertained, because the shales and sandy shales were not observed to be deposited on a reservoir rock by reason of their stratigraphic position, despite satisfying the lithological characteristics of seal or caprock. The analyzed section 6140ft- 12740ft of the OK-1 well was inferred to be the Agbada Formation (paralic sequence) of the Niger Delta Basin, by reason of depth and lithofacies within the section which are basically shale and lesser percentages of sand particles.