| 1 |
Author(s):
Ale, T.O., Ogunribido, T.H.T, Olatunji, Y.I..
Page No :
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Engineering Properties of Soil Samples From Stable and Failed Sections: An Example of Akure-Idanre Road, Southwestern Nigeria
Abstract
The engineering properties of the subsoil determine the longevity of the structure placed above it. This study is aimed
at determining the engineering properties of the subsoil taken from both the failed and stable sections of Idanre road,
south western Nigeria. Both Index and strength tests were conducted on the sampled soils. The grain size analysis
shows that the coarse contents of the sampled soils range between 73.3% and 93.9% while the fine content range
between 6.2% and 26.7% The natural moisture content, liquid limit, plastic limit, plasticity index, linear shrinkage
and specific gravity tests range from 4.1% to 13.0%, 22.2% to 40.8%, 0.0% to 25.2%, 2.9% to 38.5%, 6.4% to 10.7%
and 2.53 to 2.66 respectively. These tests results show that all the sampled soils are within the acceptable limit of a
Nigeria soil. The sampled soils are classified as either silty sand or sand. AASHTO classification shows that the
3 3 sampled soils have ratings of good to excellent. The MDD values range from 1492kg/m to 1607kg/m while the OMC
range from 10.0% to16.0%. The CBR values range from 22% to 54% which means that the soils are good as
subgrade/subbase materials and not as base materials.
| 2 |
Author(s):
Obasi, A.I, Offor, C, Igwe, E.O., Akpunonu, E.O..
Page No :
|
Integrating Spontaneous Potential and Resistivity Methods in the Delineation of Pb–Zn Mineralized Veins in the Albian Shales in Enyigba-Abakaliki, Southern Benue Trough, Nigeria
Abstract
The characters of the lead-Zinc (Pb-Zn) sulphide filled veins in response to the spontaneous potential (SP) and
electrical resistivity methods of geophysics were evaluated in eight (8) different locations around some active Pb-Zn
mines in Enyigba-Abakaliki area. Results of the survey indicate that the range of the SP values in the locations are (-
67.4 – 10.26; -118 – 30.05; -109.50 – 21.00; -99.50 – 11.81; -78.50 – 14.78; -80.50 – 11.26; 10.77 – 42.01; -64.56 –
4.23) mV, while that of resistivity are (27.34 – 147.41; 22.63 – 160.29; 27.34 – 167.21; 61.92 – 151.81; 27.34 –
176.64; 49. 35 – 148.35; 77.00 – 180.72; 62.23 - 163.44) ? m. The SP values of ≤ -50 mV and resistivity values of < 50
? m were associated with structural veins hosting Pb-Zn sulphide ores in the area. Lower values suggest higherquality deposits. The SP method displayed higher efficacy in delineating ore veins in this study. Hence, at points
where the results of both surveys were not in agreement, the result of the SP survey was preferred.
| 3 |
Author(s):
Egwuonwu, G.N, Umeobika, M.N, Okpala, P.K, Orji, O.
Page No : 1-13
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Geoelectric Investigation of Shallow Subsurface Stability at Oko-Nanka Prominent Gully Erosion Site in Niger Delta Basin, South-Eastern Nigeria
Abstract
The shallow subsurface horizons at vicinity of Oko-Nanka prominent gully erosion site in Niger Delta Basin were
surveyed. Using two-dimensional electrical resistivity tomography (2DERT) geophysical technique, the survey was
aimed at inferring the stability gully's wall and its surrounding for engineering development. The 2DERT was carried
out along accessible survey lines laid parallel and perpendicular to the flanks of the gully. Apparent resistivity data
6
collected ranging from low to high resistivity (1.22 to 1.0 x 10 Ùm) were processed using modelling software namely
Res2DInv version 3.56 hence, 2DERT models obtained with the registered data. The tomographic models obtained
show that the gully erosion site is predominantly characterized by unconsolidated earth materials. Holistic
interpretation unveils the fact that weak formations such saturated sand, sandy clay and some consolidated soil
occurrences at various depths predominates the gully site. Based on resistivity model values, the Oko and Nanka
flanks were noticed to bear significant contrast comparatively Oko-flank bearing lower resistivity range. The landsliding tendency was found to be lower at Nanka side of the gully compared Oko flank of it. Predominantly,
differential saturation was observed to be more across the profiles surveyed at the Oko side compared with those at the
Nanka side of the gully site. The variations the 2DERT models resistivity values have provided useful information for
measures of various civil engineering constructions and superstructures at the Oko-Nanka gully vicinity
| 4 |
Author(s):
Enebeli, V.C, Okorafor, C.N., Usiabulu, G.I..
Page No : 17-24
|
Geophysical Investigation for the Delineation of Lithology at Novena University, Ogume, Delta State Using the Vertical Electrical Sounding (VES) Method and Electrical Profiling
Abstract
Lithology is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of
mapping and correlation between areas. Geophysical investigation for the delineation of lithology has been carried
out at Novena University, Ogume, Delta State using the Vertical Electrical Sounding (VES) method and electrical
profiling. The major aim of this research work is to obtain the internal distribution of physical properties of a
subsurface geological structure or materials within the study area so as to guide against the challenge of dry water
wells, effective drainage channels and other geotechnical issues. The VES was acquired using Schlumberger array.
For Profiling, data acquisition was executed with 5m inter electrodes spacing in Wenner configuration. The
Petrozenith Earth Resistivity Meter was used for the field measurement in both cases. For the VES, the apparent
resistivity data were input into IP2WIN software running on personal computer. The data was inverted to obtain the
subsurface true resistivity. The VES reveals that at a probing point of about 10.11m, a resistivity less than 100? m was
encountered originating from the surface. This suggests that the near surface layer is made up of sandy clay / clay just
underlain by an unsaturated coarse sand. Beneath it is a high resistivity material of 6857? m. The high resistivity is
probably due to very low water content since the upper layer, sandy clay and clay has very low permeability for water
to reach the coarse sand layer. The line plot gotten from the profiling indicates that the near- surface geologic section
investigated is not homogeneous. The curve of profile 2 is more irregular than that of profile1. This is most likely due
to lateral changes in water content, sand grading, clay content and mineralogical compositions or texture of near
surface sand changes laterally.
| 5 |
Author(s):
Okunlola, O.A., Adeosun, B., Olisa, O.G.
Page No : 25-31
|
Compositional Features and Industrial Appraisal of Talcose Rocks around Arigbabu South-Western Nigeria
Abstract
Talc bearing rocks around Arigbabu area, in the Ife-Ilesha schist belt, were studied to delineate their compositional
features, petrogenesis and their suitability as industrial raw material. Systematic geological mapping was carried out
to identify talcose bodies in the area; petrographic studies and X -ray Diffraction (XRD) were carried out to identify
the minerals in the talcose bodies, geochemical analysis to determine elemental concentration was carried out using
Inductively Coupled Plasma Mass Spectrometry (ICPMS). Samples were also subjected to firing and geotechnical
test to determine its geotechnical properties. Results revealed the talc deposit are closely association with mafic -
ultramafic rocks, quartzite, mica schist and granites. Petrographic and XRD studies revealed that the talcose body are
composed of talc, tremolite, chlorite and anthophyllite while geochemical analysis revealed mean values of 56.02%,
25.27%, 6.6%, 2.92% and 1.13 % for SiO MgO, Fe O , Al O and CaO respectively which are comparable to other 2, 2 3 2 3
talc occurrences of southwestern Nigeria. Firing of the talc samples revealed an average Loss On Ignition (LOI) of
6.74%, average linear shrinkage value of 1.52% and mean values of water absorption capacity and pH are 10.36% and
8.08 respectively. Economic appraisal of the talc deposits indicates they are suitable as raw materials for paint,
fertilizer, paper, rubber and ceramic manufacturing, subject to appropriate beneficiation.
| 6 |
Author(s):
Okunlola, O.A., Babatunde, D.A., Olisa, O.G..
Page No : 33-41
|
Mineralisation Potential of Feldspar and Muscovite Extracts from Olode Pegmatite, Southwestern Nigeria
Abstract
Rare metal mineralisation potential of pegmatites in different pegmatite fields of Nigeria are being studied to
understand the type and level of rare metal mineralisation and provide guidelines for small and large scale mining in
the pegmatite fields of Nigeria. The Olode pegmatites in the Ibadan- Osogbo field intrudes biotite gneiss and granite
gneiss; they are characterized by large crystals of quartz, muscovite and k-feldspar with subordinate plagioclase,
while schorl and beryl are accessory minerals. Samples of pegmatites were obtained during systematic geological
mapping and minerals extracts were extracted from the samples and analyzed using Inductively Coupled Plasma
Mass Spectrometry (ICPMS). Geochemical analysis results revealed high SiO values in feldspar extract compared to 2
muscovite extracts and higher Al O value in muscovite extracts compared to feldspars extracts. The muscovite 2 3
extracts are enriched in rare metals compared to the feldspar extracts; Na/K ratio low (less than 1.0), this indicates
poor degree of albitization and this is responsible for poor mineralization of Sn. Average concentration (ppm) are 131,
24, 796 and 79 for Ba, Cs, Rb and Sr respectively in feldspar extracts and average values (ppm) are 120, 144, 42, 11
and 20 for Ga, Nb, Sn, Ta and W respectively in muscovite extracts. Plot of K/Rb against Rb showed that pegmatite
has characteristics of a unmineralised muscovite class pegmatite and Nb is mineralized in preference to Ta in the
muscovite extracts. Geochemical plots such as the Ta against Cs plot, Ta against Ga plot all show that Olode pegmatite
is a rare metal depleted pegmatite as the mineral extracts plots below the limes of mineralisation.
| 7 |
Author(s):
Aniwetalu, E., Ilechukwu, J, Ikegwuonu, O., Omoja, U.
Page No : 43-52
|
Time-lapse Porosity and Velocity Analysis Using Rock Physics Models in Niger Delta, Nigeria
Abstract
In reservoir characterization, modeling the effects of production-related changes on elastic properties of the reservoir
is a very challenging task because of the non-uniqueness and uncertainty of reservoir system. However, the analysis
of 3-D and time-lapse seismic data has offered the possibility of dynamic characterization of the porosity and velocity
changes in the reservoir during hydrocarbon production using rock physics models and vertical information available
from the well logs. The changes in the fluid properties as production progresses was analysed using fluid substitution
and depth domain seismic velocity models. The result of the initial average porosity of the reservoirs was 29.50% with
a very low water saturation of 12%. The oil and gas drive maintained average saturation of 40% and 48% respectively.
The average compressional and shear wave velocities is 2905m/s and 1634m/s respectfully with velocity increasing
with decrease in porosity. However, in fluid substitution modeling, the results reflect a change in fluid properties
where average gas and oil saturation assume new status of 34% and 24% which indicates a decrease by 14% and 16%
respectively.The average water saturation increases by 30% with an average value of 42%. The decrease in
hydrocarbon saturation and increase in the water saturation influence the elastic moduli of the reservoir rocks,
pressure, temperature and porosity. Thus, porosity decreased by 4.16% which probably arose from the closure of the
aspect ratio crack due to pressure increase. The velocity depth model of the monitor shows significant increase in
velocity and water saturation that are gradually replacing hydrocarbon in the reservoir which is an indication of
reservoir depletion.
| 8 |
Author(s):
Ogbahon, O.A, Opeloye, S.A., Oluwajana, O.A.
Page No : 53-61
|
Paleoecology and Paleodepositional Environment of Ostracod from Igumale Formation, Southern Benue Trough, Nigeria
Abstract
Ostracod fauna from Igumale Formation of the Cenomanian-Turonian Eze Aku Group in the Southern Benue Trough
have been studied to document the assemblage, paleoecology and depositional environment of the sediment in the
stratigraphic interval. Seventeen core samples spanning a stratigraphic interval of 85.34 m were analyzed for
ostracod. The lithologic composition of lithostratigraphic unit consists of siliciclastic-carbonate sequences with the
carbonates more conspicuous at the upper portion of the stratigraphic section. A total number of eight species
belonging to five genera and five families were recovered from the samples. The recorded ostracod taxa are
Bythocypris sp., Bairdia malzi, Bairdia illaroensis, Bairdia sp., Cytherella aegyptopuntata, Cytherella farafraensis,
Xestoleberis sp.and Paracosta parakefensis listed in order of decreasing abundance. Of the total population
abundance of 138, Bythocypris sp is the dominant taxa, accounts for 69.6 % of the population. Its distribution is
however cyclical, suggesting fluctuation in sea level. Based on the low species diversity, environmental preferences
of the recorded taxa and distributional pattern, shallow marine depositional environment (inner to middle shelf) is
deduced for the fossiliferous portion of the section with dissolved oxygen levels fluctuating between well oxygenated
and disaerobia
| 9 |
Author(s):
Ogunsanwo, F.O., Olurin, O.T, Ozebo, V.C., Saheed, G.A..
Page No : 63-73
|
Application of Enhancement and Filtering Technique to Aeroradiometric data of Ogun State, South-Western, Nigeria
Abstract
Enhancement and filtering primarily design for potential field problem have gained more importance in the recent
time since it can now be successfully applied to non-potential field data. They are found mostly applicable for
smoothing, noise reduction and in source edge detection. In this study, these techniques were applied to airborne
radiometric data (non-potential field) of Ogun State, in order to identify some areas which are subtle for radioelement
deposition and possible geomorphic activities attached. Three enhancement techniques, namely; Analytical Signal
Amplitude (ASA), Horizontal Gradient Magnitude (HGM) and Tilt Derivatives (TDR) were used. Filtering
techniques such as Upward Continuation, Low Pass and High Pass Filter were as well employed. The result obtained
shows variation in the responses of radiometric flux for different enhancement techniques with respect to the
geological and bedrock composition. ASA and HGM revealed unique similar trend in the radioelement distribution
compared to TDR. Upward continuation distance at 100 and 1000m was demonstrated to investigate the magnitude of
enhancement or attenuation of the radioelements and their total count. Low pass (regional) filter results revealed the
amplitude of radioelement to approach the original value while that of high pass (residual) filter approaches zero.
High pass (residual) filter result therefore shows anomalous feature similar to HGM. In this study, ASA and HGM
were found most suitable and appropriate in enhancing the trend/ pattern of distribution of radioelements and their
total count. Hence, the enhancement and filtering techniques should not be limited to only potential field but to other
non-potential, in particular, radiometric field data.
| 10 |
Author(s):
Aigbadon, G.O., Okoro, A.U, Ocheli, A.
Page No : 75-83
|
Geochemical analysis of Cenozoic Usani sandstone reservoirs, Niger Delta Basin, Nigeria: implications for reservoir quality and petroleum geology.
Abstract
Geochemical (XRD), gamma-ray log, thin section, porosity, and permeability data were integrated to interpreting the
depositional environments and evaluate the diagenetic changes, and then assess the reservoir quantity and quality of
the wells from the Usani field, Niger delta basin, Nigeria. Gamma-ray log suites and core samples descriptions show
that the reservoirs are made up of fine, medium to coarse sandstone lithofacies capped by mudstone and shale
lithofacies of different depositional settings ranging from storm dominated shelf, offshore bar to offshore regressive
bar depositional environments. The XRD and thin section data show that the dominating mineral is quartz with the
presence of feldspar, illite- smectite, siderite, and traces of hematite, pyrites minerals. The high cation exchange
capacity values of 8.10 - 8.40meq/100g for reservoirs A, A2, C2, A3, B4, B4 in the wells indicate high clay contents,
coupled with the presence of kaolinite, siderite, feldspar, illite-smectite, illite in reservoirs A, A2, C2, A3, B4, B4 at a
o
depth range of 9400 to 11800ft within a temperature range of 98-110 C in the wells in the field. These characteristics
make the sediments of the reservoirs respond faster to diagenetic changes such as compaction and cementation which
result in variation in reservoir quantity and quality by reducing the primary porosity of the Usani sandstone reservoirs
as the depth of burial increases which contribute to a decline in the quantity of hydrocarbon. The presence of sulphur
contents from the pyritic coatings affects the quality of hydrocarbon in terms of worldwide ranking.
| 11 |
Author(s):
Odunlami, B.E, Olatunji, A.S.
Page No : 85-97
|
Delineation of Hydrothermally Altered Zones in Tegina Area, North Central Nigeria
Abstract
Hydrothermally altered areas have been known to be good prospects for gold and copper mineralisation but are
difficult to map. Airborne Geophysical data (airborne radiometric and aeromagnetic) and Advanced Spaceborne
Thermal Emission and Reflection Radiometer (ASTER) data have been used to circumvent this challenge in many
places. This study was aimed at delineating possible hydrothermally altered areas around Tegina and its adjoining
areas using Geophysical and ASTER data. Surface structures were extracted from Aeromagnetic data, while Airborne
Radiometric and ASTER data using Band ratio and Spectral Angler Mapper (SAM) classification were used to
delineate zones of possible hydrothermal alterations. Geological mapping of two selected areas (A and B) were
undertaken for the validation of the results from the remotely delineated zones of presumed anomalies, while the soil
mineralogical composition was determined by X-ray diffractometer (XRD) technique. The interpreted ASTER data
revealed areas of with suspected hydrothermal alterations. These areas also coincided with areas with anomalous
K/Th ratios calculated from the radiometric data. Chlorite, montmorillonite, and kaolinite were the minerals
identified these areas confirming possible hydrothermal alterations. The structural orientation of these possible
hydrothermal trends in the NE-SW and E-W directions from the interpreted aeromagnetic data while the field
structural elements were in the NNE-SSW directions. The alteration anomalies were more pronounced in Area A than
B as observed from the mineral constituents of the soil samples from A. Argillic alteration is affirmed to be
preponderant in Area A and absent in the soil samples from Area B.
| 12 |
Author(s):
Agidi, B.M, Eze, C.I, Schoeneich, K, Irefin, M.O..
Page No : 99-108
|
Geology and Groundwater Potential of Doma 230 Topographical Sheet NE, Middle Benue Trough, Nigeria.
Abstract
Geology and Groundwater Potential of Doma 230 Topographical Sheet NE,
Middle Benue Trough, Nigeria.
| 13 |
Author(s):
Offor, C, Obasi, A.I., Ezeh, H.N, Igwe, E.O..
Page No : 109-116
|
Integrating both Air and Ground Magnetic Data in Evaluating the Magnetic Properties of the Ironstone Deposits in Lokoja Area, North Central Nigeria
Abstract
Both air and ground magnetic data were integrated into determining the magnetic character of the ironstone deposits
in Lokoja area, northcentral Nigeria. The result of the analysis indicates that their susceptibilities in residual
aeromagnetic data range from 146.68 – 168.17 nT. The susceptibility of the ores varies between those in the basement
section and those in the sedimentary environment within the study area. Those in the basement section have a lower
residual magnetic susceptibility range (194.410 – 292.99 nT) as compared with their counterparts in the sedimentary
area (375.46 – 631.27 nT). This implies that the ores in the sedimentary basins are richer in metalliferous materials
than those hosted by the basement rocks. The influence of the host rocks on the residual susceptibility anomalies in the
study area is quite minimal. The popular trend of the iron ores in the basement section is east-west direction, while
those in the sedimentary basin trend majorly in the north-south direction. The significant difference in the residual
susceptibilities of the ores from the two geologic environments, coupled with differences in their orientations
suggests that they are of different geologic ages, and could have been formed under different geologic conditions. An
analysis of the depth of occurrence of the ores indicates that they are shallow sited ( 150 m)
| 14 |
Author(s):
Akpofure, E., Debekeme, E.S..
Page No : 117-121
|
Estimated Iron (Fe) Percentage in Weathered and Ferruginized Ajali Sandstone in Western Anambra Basin, Nigeria
Abstract
A total of Ten (10) samples from Ajali Sandstone in Ayogwiri, in Etsako West Local Government Area of Edo State,
Nigeria, were collected: five representing fresh Sandstone and five representing ferruginized, weathered section of
the Sandstones. They were taken to the laboratory for quantitative determination of some chemical elements: Fe, Cu,
Mg, Na and Mn, in order to quantify the Fe percentage, using Atomic absorption spectroscopy (AAS). The result
shows that the percentage of iron ranges from 18.4% – 32.2% with an average of 26.34% in the ferruginized sandstone
- Ironstone, whereas, the percentage of iron ranges from 0.19% - 2-81% with an average of 1.61% in the fresh
sandstone samples. There is also, a slight increase in the concentration of Manganese (Mn) in the Ironstone but no
much noticeable difference in the concentration of Cu, Mg, and Na in both fresh sandstone samples and ironstone
samples. The increase of Fe percentage in the Ironstone results from weathering, leaching and accumulation of
released elements from the top layer of the Sandstone to a lower level and the hardening of the sesquioxide - rich
materials and secondary minerals. The result indicates the viability of the "Ajali Ironstone" with an average Fe
percentage of about 26.34% for the smelting of Fe at both small and large scale as the weathered zone is pervasive
| 15 |
Author(s):
Abija, F.A, Abam, T.K.S, Teme, S.C, Eze,C.L.
Page No : 129-146
|
Predicting the potential for induced earthquakes due to long term oil/gas production in the Niger Delta basin, Nigeria
Abstract
Production induced reservoir pressure dissipation causes stress changes leading to reduction in magnitude and
rotation of the horizontal stresses on fault planes. Abrupt, stick-slip and spontaneous shear displacement of the
downthrown block on crustal faults which can be due to stress perturbations is the causative mechanism of induced
earthquakes in energy production. In this studies, production induced depletion has been estimated as percentage of
predicted reservoir pore pressure at the well-fault plane interface in a horizon interval of 3500 – 3980m. The structural
attitudes of three representative fault planes were also measured from depth structure map and dynamically derived in
situ stresses determined. Fault reactivation tendency was assessed based on the Coulomb - Mohr and composite
Coulomb - Griffiths fault strength criteria to determine the optimal window for critically stressed and optimally
oriented faults for slippage. The static frictional coefficient of the reservoir bounding faults vary from 0.43 – 0.46,
0
phyllosilicate cataclastic infilling suspected for the low values. The horizontal stress orientation rotated through 3.2
0 0 0 to 17.5 causing the new orientation of the maximum horizontal stress to rotate through 108.22 to 122.5 and the
0 0 minimum horizontal stress rotated through 18.22 at 10% to 32.5 at 99% reservoir pressure dissipation on the
frictionally unstable fault plane 1. The magnitude of the maximum horizontal stress reduced from 51.2mPa to
41.5mPa and minimum horizontal stress from 36.1mPa to 26.0mPa at 99% reservoir pressure depletion. Predicted
potential for induced earthquakes increased with depletion as the optimal fault reactivation window widened from
0 0 0 0 78.1 and 36.1 under in situ conditions to 77.1 and 37.5 for all steeply dipping faults with poles within the window
and parallel to the maximum horizontal stress to reactivate and generate felt seismicity. A wider window at full
reservoir depletion imply possibility of increased number of faults and their potential risk of slippage. Injection in
water flooding operations to maintain reservoir pressure as well as enhance hydrocarbon recovery is recommended
| 16 |
Author(s):
Nwankwo, I.L., Igwe, O., Oyesanya, O..
Page No : 147-158
|
Quantifying the Ecological Risk Posed by Heavy Metals in Oil Spill Remediated Soil and Sediment in Parts of the Niger Delta
Abstract
The metal pollution status of soil and sediment was assessed using ecological risk posed by trace heavy metals in oil
spill remediated soil and sediment in parts of the Niger Delta. Remediated soil (0-15cm top and 15-30 cm bottom) and
sediment samples collected between 2010-2018 were evaluated for Lead (Pb), Cadmium (Cd), Chromium (Cr),
Nickel (Ni), Vanadium (V) Copper Cu, and Zinc (Zn) in line with the Department of Petroleum Resources guideline in
Environmental Guideline and Standard for Petroleum Industries in Nigeria. Descriptive univariate analysis which
preceded the single ecological risk index (Ei) and the potential ecological risk index (PERI) were used to evaluate the
average concentration trends of heavy metals, trace heavy metal pollution status of the study area and the impact of
the remedial measures on soil and sediment over years. With respect to their DPR target values, the result revealed
reduction in the concentration of Cr, Cd, Ni, and Zn in the topsoil and upward trend in the average concentration levels
of Cu and Pb. In the bottom soil and sediment, Zn showed an upward but its average values were much below the
given target.Similarly, sediment samples from remediated sites showed downward trends in concentration levels of
Cr, Pb, Cu, Cd and Ni Cd showed downward trend intop, bottom soil and sediment although with concentration values
above the DPR target.70% and 73% of the remediated soil sites (topsoil and bottom) and sediment, respectively, had
low ecological risk index. The general pollution status of the study area with respect to heavy metal pollution showed
increasing improvement in soil and sediment qualities in recent years.
| 17 |
Author(s):
Kwache, J.B.
Page No : 159-171
|
Geochemistry and Petrogenetic Affinity of the Rocks of Pella and Environs, Hawal Massif Northeast Nigeria
Abstract
Pella and environs is situated on Hawal Massif of northeastern Basement Complex of Nigeria. It covers an area of
2
about 216.8km . The rocks in the area has for long been described as undifferentiated Basement Complex. This paper
is aimed at differentiating and suggesting the petrogenetic affinity of the rocks by combing field data with
petrography and geochemistry. Stream, compass and road traversing were employed to geologically map
outcropping components. Petrographic studies of four thin sections were studied using Steindorff Mel Sobel
Petrological Microscope. Atomic Absorption Spectrometry (AAS) method was employed to analyze eighteen
pulverized samples. The geochemical results were interpreted using PetroGraph version 2 beta software. These
results differentiated the rocks into migmatite-gneiss, granite gneiss, Older Granites and basalts. Major mineral
modes in migmatite-gneiss, granite gneiss and the Older granites are quartz, feldspars and biotite while basalt is
dominated by plagioclase, olivine and sanidine. Migmatite-gneiss, granite gneiss and the Older Granites have
similarities of geochemical data with enrichment in SiO ranging from 67.52 - 71.02 wt. %, K O ranges from 3.35 - 2 2
4.40 wt. % and Na O ranges from 1.87 - 4.00 wt. %. Basalts are enriched in MgO with ranges from 5.99 - 6.78 wt. %, 2
TiO ranges from 3.27 - 4.35 wt. %, Fe O3 ranges from 14.1 - 15.5 wt. % and CaO ranges from 7.11 - 7.64 wt. %. 2 2
Pegmatite are enriched in K O with ranges from 9.98 - 11.4 wt. % but depleted in CaO with ranges from 0.40 - 0.76 wt. 2
% and TiO from 0.06 - 0.12 wt. %. Some selected oxides and trace elements plotted on Harker using SiO for gneisses, 2 2
granites and pegmatite and MgO for basalts as fractionation index revealed that Fe O , CaO, Co, Sr, Al O and K O 2 3 2 3 2
shows a continuous negatively correlated well-defined linear trend. The chondrite-normalized Rare Earth Elements
(REE) patterns of most of the rocks are characterized by enrichment in Light Rare Earth Elements (LREE) relative to
depletion in Heavy Rare Earth Elements (HREE). The negative anomalies shown by Eu are prominent in the rocks.
Total-Alkaline-Silica (TAS) discrimination plot of SiO vs. Na O + K O revealed that granite gneiss and granite falls 2 2 2
within granitic field. Alumina-Iron-Magnesium (AFM) diagrams for gneisses, granites and pegmatite revealed Calcalkaline while basalt is tholeiitic. Discrimination plots of Rb vs. (Yb + Ta) for granite gneiss and granites revealed
Syn-Collision (Syn-COLG) and Volcanic Arc Granite (VAG). The granites are I-type, metaluminous to weakly
peraluminous and have continental crust affinity. Basalts are Mid Oceanic Ridge (MORB) with mantle affinity. All
the rocks suggest fractionation and igneous progenitor.
| 18 |
Author(s):
Olayiwola, M.A, Aderogba, A.A., Durugbo, U.E., Fajemila, T.O..
Page No : 173-188
|
Palaeoenvironmental Reconstruction and Hydrocarbon Potential of some Mid-Upper Cretaceous and Late Eocene-Early Oligocene Sediments from Two Southern Nigerian Inland Basins: Insights from Palynology and Palynofacies
Abstract
This study investigates the paleoenvironment and hydrocarbon potentiality of mid-upper Cretaceous and late
Eocene-early Oligocene sediments from two southern Nigerian inland basins. Therefore, palynological and
palynofacies analyses were carried out on 15 outcrop samples from Calabar Flank and 112 ditch-cutting samples from
Dahomey Basin. The stratigraphic distribution of the palynofacies assemblage defined just one palynofacies unit with
very high percentage of phytoclast and very low percentages of AOM and palynomorphs all through the samples.
Palynofacies analysis of the Calabar Flank (mid-upper Cretaceous) sediments indicates deposition of their organicrich shale, calcareous shale and marl in nearshore shelf environments under dysoxic conditions, comprising mainly
kerogen types I and II. On the contrary, Dahomey Basin (late Eocene-early Oligocene) sediments signifies deposition
of organic-rich shale in shallow marine shelf environments under dysoxic–anoxic conditions containing mainly
kerogen of types I and III. The Calabar Flank and Dahomey Basin Sediments that are characterized by kerogen types I
and II, and types I and III, respectively, have capability to generate gas at depth. The findings in this present study will
be useful in understanding the depositional environments and hydrocarbon potential of Calabar Flank and Dahomey
Basin regions.
| 19 |
Author(s):
Obrike, S.E., Oleka, A.B., Ojuola, B.S., Anudu, G.K..
Page No : 189-201
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Hydro-Geophysical Assessment of Groundwater Potential and Aquifer Vulnerability of the Turonian Makurdi Formation in North Bank area, Makurdi, Middle Benue Trough, Nigeria
Abstract
Electrical resistivity investigation was carried out in North Bank and its environs in Makurdi, Benue State, with a
view to determining the depth to aquifer, aquifer thickmess, groundwater potential of the area and aquifer
vulnerability. Twenty-one (21) Vertical electrical sounding (VES) was carried out using the Schlumberger electrode
array with the aid of ABEM Terrameter (SAS 3000C) with maximum electrode spacing of 200m. The VES data
obtained were interpreted using partial curve matching approach and modelled using WinResist software. Modelled
field curves reveal essentially three to four geo-elcetrical layers and two main aquiferous zones corresponding to the
upper silty-sandstone and lower medium to coarse grained felspathic sandstones of the Makurdi Formation. The
upper silty-sandstone aquifer is characterized by low to moderate resistivity value distribution (37 - 2039 ohm-m)
with layer thickness in the range of 3m to 15m. Computed hydraulic and geo-electric characteristics (Zarrouk
parameters, hydraulic conductivity and transmissivity) depicts it as unconfined, vulnerable to infiltrating surface
2 -1 2 -1 contaminants, with low groundwater potential (0.63 m day < T 199.65 m day ) and only suitable for small
community water supply projects and private consumption. The lower felspathic sandstone aquifer is characterized
by relatively thicker sequence of aquiferous materials (3m – 54m). The aquiferous zone is generally unconfined to
2 -1 2 -1 semi-confined in nature, with groundwater potential (30.96 m day < T ≤ 542.73 m day ) seen to be largely
moderate. The aquifer is deemed suitable for industrial, irrigational and municipal water supply purposes
| 20 |
Author(s):
Obasi, P.N, Akakuru, O.C., Nweke, O.M., Okolo C.M.
Page No : 211-227
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Groundwater Assessment and Contaminant Migration in Fractured Shale Aquifers of Abakaliki Mining Areas, Southeast Nigeria
Abstract
Mineralization and mining activities in the Abakaliki area generate Metallic Trace Elements (MTEs) which disperses
and contaminate the environment. This could have serious environmental and health effects both in the vicinity of the
mines and offsite. The migration and transport of these MTEs have not been studied and could have an important role
in the degradation of groundwater in the area. This study was undertaken to evaluate the levels of hydrogeological
-
parameters, pH, Electrical conductivity, groundwater levels in wells, and geochemical assessment of Mg, Ca, Cl ,
2- SO , As, Cr, Mn, Pb, Cd, Fe, Hg, Ag, Ni, Se, Co, and Zn using atomic absorbtion spectrophotometric method. 4
Furthermore, the extent of the influence of fractures on the migration, flow direction and subsequent transport of
contaminant in the fractured shales aquifers was done using geohydrological studies and field mapping. Result
indicates that MTEs are transported in the saturated zone through fracture network which trends mainly in the NW –
SE direction, this controls groundwater occurrence and hydrothermal mineralization in the area. The distribution of
geochemical elements indicates higher concentrations in wells within the mining areas and downstream. This is be
- 2- due to non connectivity of fractures; formations of water divide; and soil/ rock/ water interaction. Levels of Cl , SO , 4
As, Mn, Pb, Cd, Fe, Hg and Se in some wells are above the World Health Organization and Standard Organization of
Nigeria guidelines for drinking water. No principal flow direction was indicated, but Northeasterly and Southeasterly
groundwater flow vectors were observed. Conceptual models reveal predominance of recharge area in the central
parts while the northern and southern parts form the discharge areas. This is useful for proper water resources and
waste management planning. The hydrogeological and geochemical investigations show that the contaminants are
geogenic rather than anthropogenic.
| 21 |
Author(s):
Ominigbo, O.E.
Page No : 229-236
|
Evolution of the Nigerian Basement Complex: Current Status and Suggestions for Future Research
Abstract
The polycyclic basement rocks of Nigeria have been the subject ofseveral isolated and localstudies. Despite the huge
amount of studies on the basement however, the geodynamic evolution of the basement remains a subject of debate.
This study highlights some of the major existing studies on the basement complex with a view to streamlining the
existing knowledge into a coherent perspective as well as identifying potential areas for future research that will
improve our understanding of the evolution of the Nigerian Basement Complex (NBC). The polyclicity of the
basement poses a major challenge in deciphering episodicity of the events leading to the geodynamic evolution of
the region. The reported occurrences of pre-Pan-African rocks in some parts of the basement are interpreted as
reflecting the relicts of reworked older crustal materials which cannot be regarded as juvenile earth materials. Thus,
such Eburnean orsimilar older ages cannot be inferred to represent the primary isotopic age of magmatism and other
associated thermo-tectonic events within the basement. Lack of integrated, comprehensive structural and isotopic
data is identified as part of the missing links resulting in the present poor understanding of the complex. Integrated,
regional geoscientific studies employing modern techniques and tools are needed to fully understand the geodynamic
evolution of the Nigerian basement rocks. To do this, quantitative models, structural analyses and modern
geochronological dating techniques are recommended. It is also recommended that mineral exploration should be
intensified within the Older Granites as this will not only enhance the understanding of the mineralization potentials
ofthese rocks but also provide clearerinsightsinto the general evolution ofthe basement complex.
| 22 |
Author(s):
Akudo, E.O., Egboka, B.C.E., Aniwetalu, E, Nwankwoala, H.O..
Page No : 237-245
|
Soil and Water Assessment Tool (SWAT Model) for Estimating Groundwater Recharge in Sokoto-Rima River Basin, Northwestern Nigeria
Abstract
This research was undertaken to provide a procedure to improve existing approaches to the estimations of
groundwater recharge and compute values for other hydrological parameters at sub-basin level and monthly intervals.
Using the distributed hydrological model ''Soil and Water Assessment Tool'' (SWAT), the groundwater recharge was
2
estimated for the entire Sokoto-Rima River Basin, covering 72,498.711km . The procedure involved model
calibration and validation based on measured river discharges, and statistical quantification of the goodness-of-fit
using SWAT-CUP, a semi-automated approach (SUFI-2) for sensitivity analysis. The SWAT model was calibrated
(2006-2010) and validated (2011-2014) at Kende for the entire Sokoto-Rima River Basin. The simulated river
3 3
discharge yielded a mean monthly discharge of 96.25m /s at calibration and 95.65m /s at Validation. The estimated
groundwater recharge was 182.10mm, which is 18% of the mean annual rainfall of 1019mm. The computed mean
annual potential evapotranspiration, actual evapotranspiration, and surface runoff were 1600m, 500mm, and
236.53mm respectively. A comparison of observed and simulated monthly river discharges showed a coefficient of
2 2 determination (R ) of 68.3% and Nash-Sutcliffe efficiency (NSE) of 98% for calibration and R of 65.7% and NSE of
84% for validation periods respectively. Although the modeling proved successful and was applied in estimating
groundwater recharge and other hydrological parameters, there are, however, two limitations in the Sokoto-Rima
basin model: (1) there were just 2 river discharge measuring points in the entire watershed, and (2) SWAT capabilities
were also affected by limited data on available reservoir/impoundments and agricultural management information.
| 23 |
Author(s):
Ajagbe, T.N., Akanbi, E.S.
Page No : 247-256
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Soil and Groundwater Contamination at an Active Mine Site in Kwang Rayfield Jos Plateau State Using Electrical Resistivity and Heavy Metal Analysis
Abstract
A 2-D electrical resistivity survey and heavy metal analysis was carried out at an mine site in Kwang Rayfield, Jos,
Plateau state to investigate soil and groundwater contamination. This survey was carried out using the WennerSchlumberger configuration. The 2D electrical resistivity was carried out along three profiles; two profiles at the mine
site and one profile taken far away from the mine site to serve as the control profile. The apparent resistivity data
obtained was iteratively inverted using RES2DINV software to generate the 2D resistivity sections. Relatively low
resistivity values within the subsurface of each profile followed the order Profile 1 > Profile 2> Profile 3. The results
revealed that the subsurface beneath P2 is more resistive than P1 and this could be because there was no mining
activity as of the time of the survey. Profile 3 revealed relatively high resistivity values at the top soil and it could be
due to the pressure on the field as result of people playing football. The 2D electrical resistivity survey was able to
show lateral and vertical resistivity variations beneath the profile and regions of low resistivity that indicate possible
contamination subsurface material with metals. Contents of heavy metals in soil and water was determined using Xray Fluoroscopy machine and Atomic absorption spectrometer respectively. Heavy metal concentration in soil
samples revealed the presence of heavy metals with the concentration of Strontium, Manganese, Lead, Zinc, Copper,
Chromium, Vanadium, Tin, and Nickel lower than the permissible limits. Some heavy metals were not detected in the
soil samples; Nickel in S1; Copper, Chromium, Vanadium and Tin in S2; and Copper, Chromium, Vanadium,
Uranium, Calcium, Potassium, Tin, and Nickel in S3. The heavy metal analysis on water samples revealed the
presence of heavy metals with Lead concentration more than the permissible limit given by WHO (2017) and SON
(2015); and Copper concentration more than the guideline limit given by SON (2015). The low resistivity observed in
Profile 1 where active mining was taking place and the presence of these heavy metals indicates possible heavy metal
contamination of water and soil (on the surface and within the subsurface) at the mine site.
