Base Metal Mineralization in the Precambrian Rocks of Okemesi-Ijero Area, Southwestern Nigeria

Scientific Review
ISSN(e): 2412-2599, ISSN(p): 2413-8835
Vol. 2, No. 4, pp: 57-67, 2016
URL: http://arpgweb.com/?ic=journal&journal=10&info=aims
*Corresponding Author
57
Academic Research Publishing Group
Base Metal Mineralization in the Precambrian Rocks of
Okemesi-Ijero Area, Southwestern Nigeria
Ayodele O.S.* Department of Geology and Applied Geophysics, Ekiti State University, P.M.B. 5363 Ado Ekiti,
Nigeria
Madukwe Y. Henry Department of Geology and Applied Geophysics, Ekiti State University, P.M.B. 5363 Ado Ekiti,
Nigeria
Azeez M.A. Department of Chemistry, Ekiti State University, P.M.B. 5363 Ado Ekiti, Nigeria
Awokunmi E.E. Department of Chemistry, Ekiti State University, P.M.B. 5363 Ado Ekiti, Nigeria
1. Introduction
The search for concealed mineral deposits has led to the development of numerous sampling media that can
unravel such hidden mineral deposits. Some of the important geochemical sampling media that have been used
successfully in the recent past include soil, stream sediment, and termitarium or termite mound [1, 2] Rock as a
medium for reconnaissance geochemical prospecting for mineral deposits is not used as much as soil and stream
sediments. This is because of the difficulty involved in sampling representative rocks and the pattern of distribution
of outcrops within an area [3]. Whole rock sample analysis can however, provide important information concerning
the range of trace elements present, their primary dispersion in rock and the mineralogical relationships [4]. Putman
and Burnham [5] used whole-rock analyses in a regional study of a part of the Arizona copper province. The
Geological Survey of Canada, according to Sakrison [6] carried out regional geochemical survey using whole-rock
samples.
The understanding of „base metals‟ differs in different disciplines. While an electrochemist explains them in
reference to metals in the lower end of the electrochemical series [7] while metallurgist understands them as the
bases on which other elements are coated [8]. To geologist, base metal refers to high volume, low-value metallic
elements such as copper, lead and zinc. Mumbfu, et al. [9] explored for gold using stream sediments from the Ngo
Vayang area of southern Cameroon. The study revealed that the Au-Hf element association from the R-mode factor
analysis indicated gold mineralization while U-Th-Pb-W, Nb-Ta-Co-V, Au-Hf-Cu associations reflected lithologic
controls. Emmanuel, et al. [10] carried out geochemical investigation of the southern part of Ilesha using
multivariate analysis to obtain the coefficient of principal components. The elemental association ratio revealed high
metallic concentrations, which led to the mineralization trend in southern Ilesa [10]. Okunlola and Okorojafor [11],
studied the geochemical and petrogenetic features of the schistose rocks of the Okemesi fold belt, and revealed that
the metasedimentary assemblages which form the inner portion of the Okemesi antiform are continental post
Abstract: The evaluation of base metals in the bedrocks of Okemesi / Ijero area, southwestern Nigeria has
been carried out to assess their potentials, level of accumulation and enrichment. The methodology included
systematic geological and geochemical mapping of the rocks using grid-controlled sampling method at a
sampling density of one sample per 500m. Ten rock samples were collected at different locations of the study
area. The results obtained showed that the major oxides such as SiO2, Al2O3, TiO2, Fe2O3, MnO, MgO, CaO,
Na2O, K2O and P2O5 were detected in variable proportions. While SiO2 varied between 70.59% and 98.70%,
Al2O3 ranged between 15.73% and 0.61%. There is abundance of barium (Ba), silver (Ag) and gold (Au) with
concentration values of 1.6-9.8, 1.24-7.1 and 0.05-10.00 ppm respectively. Base metals such as Cu, Zn, Pb, Bi
and Cr enrichment factors and their geo-accumulation index indicates moderately significance to very high
enrichment of Cu (10 – 70%) , Pb (20 – 40%) and Bi (10 – 40%). The geo-accumulation indices suggest
geogenic concentration of the base metals in the host rocks rather than anthropogenic inputs. The PCA elements
loaded Au, As, Ag, Pt and Os on the same factor and they are pathfinder elements of Gold. Correlation
coefficients indicate strong positive correlations between the elements. This implies that they are strongly related
and therefore of the same source, also suggesting geogenic sources.
Keywords: Bedrocks; Mineralization; Base metals; Enrichment factor; Index of geo-accumulation.

Scientific Review, 2016, 2(4): 57-67
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Archean supracrustals. Stream sediment geochemistry can aid in recognizing variations in upstream geology in
several high grade metamorphic litho-tectonic units having different metamorphic and tectonic histories [12]. The
aim of this research is to evaluate the base metal potentials in the bedrocks of Okemesi/Ijero Area, southwestern
Nigeria with the objectives of harnessing it for economic and industrial development of Ekiti State. The study areas
(Okemesi and Ijero) lies between latitudes 7°46′N to 7°53 ′N and longitudes 5°00′E to 5°07′E (Figure 1).
Figure-1. Map of Ekiti State showing the study area
2. Geologic Setting
The study area is located within Ekiti State and is underlain by crystalline rocks of Precambrian basement
complex of southwestern Nigeria, which is also part of the basement complex rocks of Nigeria. The rocks in the area
have different textural classes ranging from coarse to fine grained. Structural complexity is a common feature of the
basement complex of Nigeria [13]. The rocks in the study area are most likely products of multiple folding, igneous
and metamorphic activities and polycyclic deformation [14]. All the rocks encountered during field examination of
the area have been compiled to produce a working geological map of the study area (Figure 2).The study area is also
part of the regional Dahomeyide fold belt defined by Affaton, et al. [15] and it is not an exception to the structural
and deformational episodes that pervaded Nigeria‟s Precambrian basement complex.
Within the basement complex, tectonic deformation has completely obliterated primary structures [16] except in
a few places where they survived deformation [14]. The Ifewara fracture zone separates the rock of Ilesha schist belt
into two structural units of contrasting lithologies [17-20]. Other researchers [21-24] have provided evidences in
support of the existence of the structure as well as its significance in terms of tectonic movements. Also, sutures
have been proposed along the two transcurrent fault zones, and in particular within the Ife-Ilesha schist belt, which
has been interpreted as a back-arc marginal basin [13], and east-verging nappes [25]. It is worthy of note that the
Ilesha schist belt hitherto thought to be devoid of iron ore deposits has been reported to host some deposits of
“banded iron formation” [26]. The Nigerian basement complex forms part of the Pan – African mobile belt and lies
between the West African and Congo cratons and south of the Tuareg shield [27]. It is intruded by the Mesozoic
Calc-alkaline ring complexes (Younger granites) of the Jos plateau and is unconformably overlain by Cretaceous and
younger sediments. The Nigerian basement complex was affected by the 600Ma Pan African orogeny and it
occupies the reactivated region, which resulted from plate collision between the passive continental margin of the
West African craton and the active Pharusian continental margin [28, 29]. The Basement rocks are believed to be the
results of at least four major orogenic cycles of deformation, metamorphism and remobilization corresponding to the
Liberian (2,700Ma), the Eburnean (2500Ma), the Kibaran (1100Ma), and the Pan-African cycles (600Ma). The first
three cycles were characterized by intense deformation and isoclinals folding accompanied by regional
metamorphism, which was further followed by extensive migmatization. The Pan-African deformation was
accompanied by a regional meta-induced syntectonic granites and homogenous gneisses. Late tectonic emplacement
of granites and granodiorites and associated contact metamorphism accompanied the end stages of this last
deformation. The end of the orogeny was marked by faulting and fracturing [30]. Anifowose [24] was of the opinion
that the granitic emplacement was probably controlled by fractures within the basement, and also showed outcrop
pattern indicating that the older granite cut across all other structures with sharp and chilled contact. Within the

59
basement complex of Nigeria, four major petro-lithological units are distinguishable [29], namely; the migmatite –
gneiss-quartzite complex, the schist belts, the Pan African granitoids and under formed acid and basis dykes. Major
rivers in the study area include river Osun found along Okemesi road, river Oyi, which flows in a southerly
direction. A waterfall was encountered around Oke-Ila called Ayikunnugba waterfalls and river Isa etc. The streams
spread out from a central point, forming dendritic drainage pattern as a result of its branching (Figure 3).
Figure-2. Geological map of the study area [31]
Figure-3. Drainage map of the study area [31]
3. Method of Study
The field operation was essentially geologic mapping of the study area, to determine the underlying bedrock
units. The geologic mapping was carried out at a scale of 1:50,000 using grid-controlled sampling method at a
sampling density of one sample per 4sq km2
for the collection of rock samples. Ten rock samples were obtained. The

60
rock samples were collected from different localities within the study area, after which they were labeled
accordingly to avoid mix up. The location of each outcrops were determined with the aid of a Global Positioning
Systems (GPS) and the lithologic and field description of each samples were correctly recorded. The samples were
bagged and transported to Petroc Laboratory, Ibadan, where it was pulverized and crushed using standard
procedures. The samples were later digested using the total digestion method. 40g of the digested samples were
introduced into containers provided and properly labeled, and were sent to ACME Laboratories, East Vancouver,
Canada for geochemical analysis to determine the major oxides using atomic absorption spectroscopy (AES). Trace
and rare earth elements were determined using inductively-coupled-plasma mass spectrometry (ICP-MS). Bivariate
and multivariate statistical analysis was applied on the geochemical data using SPSS statistical software package to
obtain elemental correlation coefficients, base metal and gold paragenesis,. The Pearson linear correlation coefficient
[32] is a statistical method of checking for linear relationships between two variables. A value of 1 indicates a
perfect positive or direct relationship between two variables. A value of -1 indicates a perfect negative or inverse
relationship, while a value of zero indicates a lack of any correlation.
4. Results and Discussion
4.1. Geological Field Mapping
The field description and characteristics of the various rock units mapped in the study area have been compiled
a geological map (Figure 3). The geological map revealed the dispositions of the various rock units in the area. Also,
from the geological map, migmatites are the oldest rocks in the study area, a few lithologies such as the pegmatites,
mica schists, charnockites and granites occur as intrusive bodies within the migmatite-gneiss, and others such as
granite-gneiss, calc-gneiss etc. form discrete, disseminated and linear bodies within the massive quartzites and the
schistose types. The strike values of the quartzite (schistose and massive) range from 024°-046° in some places.
Also, the rocks dip in the western direction, with values such as 40°W - 80°W in some areas of study, while other
areas also dip in the eastern direction with dips such as 72°E - 80°E respectively. The high dip values could be
attributed to several episodes of deformation that characterize the rocks in the area, which is manifested in the brittle
nature of the quartzites. These display several joints and fracture sets and control the drainage pattern in the area.
Also, there is existence of structures in the area as can be seen on the cross-section map. This confirmed the presence
of folding on the rocks especially on the schistose quartzites; this type of fold is an antiform.
4.2. Major Oxide Geochemistry
The analytical geochemical results of the various rocks mapped are presented in Table 1. From the result
obtained, the most prominent oxides in the samples are SiO2, Al2O3, Na2O and K2O with average values of 80.58%,
14.78%, 2.73%, and 2.52% respectively. The SiO2 content of the sample from the study area ranges between 70.59%
and 98.70%) with an average value of 80.57%. Also, from the result presented, SiO2 has the highest concentration in
all the rocks analysed. Al2O3 content is moderate in all the samples analyzed except in Ajindo sample which is
relatively higher than others. The values range from 0.71% to 46.22% with an average value of 14.78%. The TiO2
values vary between 0.01% and 1.21% with an average value of 0.22% and are considerably very low in all the
analysed samples. Its concentration is highest in the samples
Table-1.The major oxides in the rocks (%)
from Ajindo. The Fe2O3 values range between 0.01% and 3.19% with an average value of 0.81% of the total rock content. The highest
concentration (3.19%) is detected from Ajindo which is underlain by ferruginous quartzite. MnO and MgO values ranges between (<0.01%-
0.08%) and (<0.01%-0.44%) respectively with average values of 0.06% and 0.19% respectively. Other oxides such as CaO, P2O5, Na2O and K2O
have fair to low concentration in all the rocks analysed.
4.3. Trace Elements Geochemistry
The trace elements analysed in the rocks are as follows: Cu, Zn, *As, *Pb, Rb, *Ir, Sr, *Pt, Zr, *Os, *Ag, Ba,
Re, Eu, Au, V, Cr and Bi (Table 2). The results revealed that the concentrations of *Ag, Au, V are considerably high
when compared with other trace elements and rare earth metals. Barium (Ba) and Gold (Au) have high
concentrations in the range (1.60-9.80) and (0.05-10.00) in all the locations. The concentrations of the metals present
in ppm are: Cu (0.02-0.33); Zn (0.004-0.01); Rb (0.01 and 0.021) and Sr (0.042-0.94); *As and*Pb (0.01- 0.04). The
latter elements are pathfinder elements for Au, the values indicate low Au potential in the areas under

61
investigation.*Ir, *Pt and *Os concentration ranges between 0.0050 and 0.024) respectively. Pt shows minimum
presence in samples from Ipoti and Odo-Owa while Os is only present in the
Table-2. Concentration of Trace and Rare Earth Metals in the rocks (ppm)
BDL- below Detection Limit, MDL- Mean Detection Limit, (*)-pathfinder elements of gold Sample from Ipoti. Zr, Re, and Eu have average
values of 0.018 ppm, 0.41Lppm and 0.018 ppm respectively. Rhanium, established more pronounced presence in almost all the samples than Zr
and Eu. Cr and Bi values range from 0.002 to 0.04 ppm and 0.004 to 0.49 ppm with average values of 0.022ppm and 0.087ppm respectively. Cr is
of relatively high concentration in Okemesi.
Particularly useful ratios include K2O/Na2O, SiO2/CO2, and SiO2/total volatiles; the volatiles commonly include
H2O, CO2, S, as and B [33]. According to Horsnail [33], many types of mineral deposits are characterized by a
consistent increase in the ratio K2O/Na2O, which is essentially a manifestation of increasing potassic alteration.
Similarly, a number of mineral deposits, particularly those enriched in gold and silver, are marked by a consistent
decrease in the ratio SiO2/CO2 as ore is approached. The ratio SiO2/total volatiles exhibits considerable variation
among the various types of mineral deposits; in most cases, skarns excepted, there is a consistent decrease in the
ratio as mineralization is approached [33]. The K2O/Na2O ratio for the samples range between 0.03 and 144.5, the
highest value came from Ajindo while the lowest are from Ijero quarries. The Ajindo due to its high potassic
alteration might be a good area for mineralization. The correlation plot of K2O vs. Na2O (fig. 4) gives a negative
correlation an indication of potassic alteration. The ratio SiO2/total volatiles for the samples range from 122 to 235;
this is high which suggests that the areas are far from mineralization and a plot of SiO2 against the volatiles indicates
negative correlation (fig.5).
Figure-4. Correlation plot of K2O vs. Na2O
y = -0.1805x + 3.1764
R² = 0.0286
0
1
2
3
4
5
6
7
8
9
0 2 4 6 8 10
Na2O(%)
K2O (%)

62
Figure-5. Correlation plot of SiO2O vs. volatiles
4.4. Correlation Coefficients and Principal Component Analysis
The interrelationship between elements in the rocks is presented in Table.3. The result shows a strong positive
correlation between the elements. This implies that they are strongly related and therefore of the same source,
suggesting geogenic sources.
With regards to the PCA, the concentration dataset is divided into subsets, represented by different factors. The
elements in each subset are correlated with one another and are largely independent of the elements in the other
subsets (Table 4). According to Deng, et al. [34] factors should be representative of the underlying geological and
metallogenical process that created the correlations among these variables. Based on PCA, the elements were
classified into two factors. The second factor is important because Au, As, Ag, Pt and Os are situated on this factor
and they are pathfinder elements of Gold. Figure 6 is a plot of the components showing metallic affinities.
Table-3. Bivariate and multivariate statistical analysis of trace and rare metals using Spearman correlation coefficients
y = -0.0004x + 0.5375
R² = 0.0021
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 20 40 60 80 100 120
Volatikes(%)
SiO2 (%)
Cu Zn As Pb Rb Ir Sr Pt Zr Os Ag Ba Fe Eu Au V Cr Bi
Cu 1
Zn 0.999523 1
As 0.99923 0.999619 1
Pb 0.999634 0.999723 0.999441 1
Rb 0.999369 0.999574 0.999423 0.999559 1
Ir 0.999293 0.999174 0.999441 0.998991 0.999179 1
Sr 0.999138 0.999634 0.999592 0.999418 0.999196 0.998581 1
Pt 0.99997 0.999999 0.999969 0.999929 0.999986 0.99979 0.999958 1
Zr 0.999664 0.99987 0.999602 0.99976 0.999821 0.999512 0.999403 0.999997 1
Os 0.999977 0.999999 0.999965 0.999987 0.99999 0.999873 0.999974 1 1 1
Ag 0.998989 0.999409 0.999646 0.999548 0.999584 0.999401 0.99903 0.999912 0.999639 0.999945 1
Ba 0.999551 0.999551 0.999322 0.999686 0.999767 0.999104 0.99935 0.999985 0.999794 0.999989 0.999409 1
Fe 0.99945 0.999566 0.999288 0.999516 0.999867 0.99912 0.999065 0.999962 0.999805 1 0.999379 0.99979 1
Eu 0.999355 0.99933 0.999566 0.999302 0.999584 0.999143 0.99932 0.99996 0.99948 1 0.999228 0.999588 0.999539 1
Au 0.998709 0.999064 0.999466 0.999101 0.999384 0.999519 0.9985 0.999884 0.999389 0.999921 0.999835 0.998985 0.999039 0.998966 1
V 0.999241 0.999637 0.998977 0.999356 0.99945 0.998502 0.999028 0.999961 0.999505 0.999966 0.998781 0.999308 0.999507 0.999291 0.998458 1
Cr 0.998846 0.999502 0.99974 0.999254 0.999723 0.999089 0.999358 0.999979 0.999557 0.999996 0.999642 0.999314 0.99946 0.999536 0.999527 0.999186 1
Bi 0.998853 0.999252 0.998995 0.99873 0.998231 0.997868 0.999481 0.999966 0.998712 0.999977 0.997854 0.998368 0.998378 0.998668 0.997261 0.998816 0.998462 1

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Table-4. Principal Component Analysis (PCA) of trace and rare metals
Component
1 2
Zn 0.867 0.145
Bi 0.776 -0.04
Sr 0.77 0.039
Zr 0.752 0.176
V 0.671 -0.314
*Pb 0.61 0.043
Re 0.581 -0.136
Cu 0.503 -0.306
Ba 0.474 -0.339
Rb 0.406 -0.037
Eu 0.249 -0.092
*Pt -0.221 0.916
*Ag 0.015 0.885
Au -0.246 0.867
*As 0.408 0.717
*Os -0.209 0.706
Cr 0.308 0.591
*Ir -0.151 0.532
Figure-6. Component plot in rotated space of the studied samples
4.5. Enrichment Factor
The results of the enrichment factor on the base metals, statistical summary and percentage enrichment factor
are shown in Tables 5, 6 and 7 respectively while the histogram of distribution of the base and precious metals in the
rocks is shown in Figure 7.
A common approach to estimate how much rocks and sediments are impacted (naturally and anthropogenically)
with metal is by calculating the Enrichment Factor (EF). According to Sutherland [35], EF of a metal in sediment
can be calculated using the expression:
[ ]
[ ]
where Cmetal and Cnormalizer are the concentrations of metal and normalizer in sample and in unpolluted control.
Al has a constant value of 1 throughout the analysis which showed that it is the base element for the analysis.
Minerals like Cu, Pb and Bi showed moderately to extremely high enrichment (10 – 70%, 20 – 40% and 10 – 40%),
while Ti was noted to exhibit extremely high enrichment of 100%.

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4.6. Index of Geoaccumulation (Igeo)
The index of geo-accumulation of the base metals is shown in Table 8 while the statistical summary is presented
in Table 9. The fact that all the value indicated in the geo-accumulative statistics table is below 1 implies that the
metals are from geogenic sources (they are all naturally occurring elements). Therefore, all the base metals are from
geogenic sources with little or no anthropogenic contribution.
Table-5. Enrichment Factors (EF) for the base metals
Sample ID EF (Cu) EF (Pb) EF (Zn) EF (Ag) EF (Bi) EF (Cr) EF (Ti) EF (Al)
Okemesi 1 Qtz 83.755 11.965 2.393 0.55039 97.7142 0.31907 5721.39 1
Okemesi 2 Qtz 89.8421 17.152 1.63349 0.58397 24.5024 0.0245 3814.67 1
Ijero Quarry A 64.3685 14.304 1.10857 1.14433 12.1585 0.0143 238.601 1
Ijero Quarry B 12.2482 2.2563 0.12893 0.70266 1.28929 0.25786 107.53 1
Ijero Quarry C 91.8743 8.3522 0.25057 0.51227 15.3124 0.03898 92.8799 1
Itawure 1 Qtz 7.23958 1.9051 1.14309 0.87256 3.81031 0.30482 1525.4 1
Itawure 2 Qtz 118.643 4.1267 1.03168 0.72733 5.1584 0.05158 1204.63 1
Ajindo Qtz 2.29014 0.5725 0.0458 0.14199 0.57254 0.03893 4622.31 1
Ipoti Quarry 182.718 56.705 12.6012 39.0638 63.0062 3.78037 2101.96 1
Odo-Owa Quarry 149.085 298.170 16.3993 52.9252 14.9085 5.9634 2486.83 1
Table-6. Statistical Summary for the Enrichment Factor
Enrichment Factor MIN MAX AVER STDEV
EF (Cu) 2.2901 182.718 80.206 60.769
EF (Pb) 0.5725 298.17 41.550 91.647
EF (Zn) 0.0458 16.399 3.6735 5.8200
EF (Ag) 0.1419 52.925 9.7224 19.395
EF (Bi 0.5725 97.714 23.843 31.764
EF (Cr) 0.0143 5.963 1.0793 2.0674
EF (Ti) 92.879 5721.39 2191.62 1974.21
EF (Al) 1 1 1 0
Table-7. Percentage Enrichment of the base metals
Class Sediment Quality Cu Pb Zn Ag Bi Cr Ti
Percent
EF <2
Deficiency to
Mineral Enrichment 0 20 70 80 20 80 0
EF= 2- 5
Moderate
Enrichment 10 20 10 0 10 10 0
EF=5-20
Significant
Enrichment 20 4020 0 40 10 0
EF = 20-40
Very High
Enrichment 0 0 0 0 10 0 0
EF >40
Extremely High
Enrichment 70 20 0 20 20 0 100

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Figure-7. Histogram showing Base metal distribution in the rocks
Table-8. Index of geo-accumulation of the base metals
ELEMENTS Cu Pb Zn Ag Bi Cr Ti Al
Okemesi 1 Qtz -2.553 -3.397 -2.096 1.264 -2.185 -1.574 -3.320 -0.475
Okemesi 2 Qtz -2.533 -3.251 -2.273 1.280 -2.796 -2.699 -3.507 -0.486
Ijero Quarry A -2.619 -3.273 -2.383 1.630 -3.043 -2.875 -4.652 -0.428
Ijero Quarry B -3.295 -4.03 -3.273 1.463 -3.972 -1.574 -4.953 -0.383
Ijero Quarry C -2.356 -3.397 -2.921 1.389 -2.834 -2.331 -4.953 -0.319
Itawure 1 Qtz -3.596 -4.176 -2.398 1.484 -3.574 -1.574 -3.874 -0.456
Itawure 2 Qtz -2.513 -3.972 -2.574 1.274 -3.574 -2.477 -4.108 -0.587
Ajindu Qtz -3.574 -4.176 -3.273 1.218 -3.875 -1.945 -2.871 0.066
Ipoti Quarry -3.412 -3.920 -2.574 1.917 -3.574 -1.699 -4.953 -1.674
Odo-Owa Quarry -3.574 -3.273 -2.533 1.9762 -4.273 -1.574 -4.953 -1.747
Table-9. Statistical Summary of Index of Geo-accumulation for the base metals
Geo-accum MIN MAX AVER STDEV
Igeo Cu -3.596 -2.356 -3.003 0.525
Igeo Pb -4.176 -3.252 -3.686 0.398
Igeo Zn -3.273 -2.096 -2.629 0.401
Igeo Ag 1.218 1.976 1.489 0.271
Igeo Bi -4.273 -2.184 -3.369 0.640
Igeo Cr -2.875 -1.574 -2.032 0.516
Igeo Ti -4.954 -2.871 -4.215 0.789
Igeo Al -1.748 0.066 -0.649 0.586
5. Conclusion
This study has provided useful information on the lithological characteristics and geochemical background
values of the various base metals present in the bedrocks of Okemesi/Ijero area, which serves as a useful guide in
exploration and exploitation of these metallic resources. The rocks contain high silicon content and moderate
aluminum, sodium and potassium oxide contents. This high content of silica is responsible for their hardness and
their high resistance to weathering, which could make them useful construction raw materials. Also, the enrichment
factor result showed that Cu, Pb and Bi has moderate to extremely high enrichment, while Ti has extremely high
enrichment. Also, there is structurally-controlled type of mineralization as observed in the pattern of emplacement of
the bedrocks. The results also suggest possible showings of gold mineralization in the studied area, though a further
geochemical assertion is still required to delineate the auriferous zones. It can however be concluded that the base
metals analyzed are from geogenic sources, as there no trace of anthropogenic inputs in their geo-accumulation
0
20
40
60
80
100
120
Cu Pb Zn Ag Bi Cr Ti
EnrichmentFactor(%)
Elements
EF <2, Deficiency to Mineral Enrichment EF= 2- 5, Moderate Enrichment
EF=5-20, Significant Enrichment EF = 20-40, Very High Enrichment
EF >40, Extremely High Enrichment

66
index. Radiometric dating of the rocks to determine its petrogenetic characteristics and detailed structural mapping
of the studied area to identify nappe structures are recommended. The Correlation coefficients indicate strong
positive correlations between the elements. The PCA elements loaded Au, As, Ag, Pt and Os on the same factor and
they are pathfinder elements of Gold.
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