




































Asian Review of Environmental 

and Earth Sciences 
ISSN: 2313-8173 
Vol. 1, No.3, 66-83, 2014 

http://www.asianonlinejournals.com/index.php/AREES 

 
 

 

* Corresponding Author 

 

 

66 

 

Petrostructural and Mineralogical Assessment of the 

Precambrian Rocks in Ikere Area, Southwestern Nigeria 
 

Olusiji Samuel Ayodele
1*

 --- Segun Ajayi Akinyemi
2
 

 
1,2

Department of Geology, Ekiti State University, Ado-Ekiti. Nigeria  

 

Abstract 

 

 

 

 

 

 

 

 

 

 

 

 

 
 

 

 

 

 

 

 

 
This work is licensed under a Creative Commons Attribution 3.0 License 

Asian Online Journal Publishing Group 
 

Contents 
1. Introduction ............................................................................................................................................................................... 67 

2. Location of the Study Area ....................................................................................................................................................... 67 

3. Charnockites .............................................................................................................................................................................. 68 

4. Results ........................................................................................................................................................................................ 68 

5. Discussion ................................................................................................................................................................................... 81 

6. Conclusion .................................................................................................................................................................................. 82 

References ...................................................................................................................................................................................... 82 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Petrological and mineralogical evaluation of the basement rocks in Ikere Ekiti, southwestern Nigeria 

was carried out with the aim of determining the petrological characteristics and mineral composition 

of the various rock units dominating the study area in an attempt to unravel the pattern of 

deformation on the rocks. The method of investigation includes systematic geologic mapping to 

determine the underlying rock units, petrographic studies of the thin sections using light transmitting 

Petrological Microscope and; analysis and interpretation of the structural elements inherent in the 

rocks using rosette diagrams. Seventeen (17) rock samples were collected on the field out of which 

ten (10) fresh rock samples were selected and prepared for thin section studies using standard 

procedures. Geologic mapping of the studied area revealed that the rocks occured as plutons (older 

granite) while the charnockites and granites occur as pegmatitic intrusions into the older rock 

sequence. The granites and charnockites were extensively dissected by a network of intersecting or 

crosscutting quartzo-feldspathic stringers or veins/veinlets of various widths and dykes, which is an 

indication of the relevant post-tectonic deformation episodes and deuteric alteration in the 

evolutionary history of the rocks. Also, the rocks are rich in quartz and feldspar with significant 

amounts of heavy minerals such as zircon, tantalite, tourmaline, heamatite, topaz and opaque 

minerals such as casiterite, chalcopyrite, sulphide and pyrrhotite.  
 

      Keywords: Rock units, Petrography, Rosette diagram, Photomicrographs, Minerals, Structures. 

http://creativecommons.org/licenses/by/3.0/


Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

67 

 

1. Introduction 
The basement complex of southwestern Nigeria lies within the reactivated part of the Pan-African mobile belt 

between the West African and Congo Cratons [1, 2]. The basement complex is believed to have evolved as a result of 

at least four major orogenic cycles of deformation, metamorphism and remobilization corresponding to the Liberian 

(2,700Ma), Eburnean (2000Ma), Kibaran (1,100Ma) and the Pan-African cycle (600Ma). The first three cycles were 

characterized by intense deformation and isoclinal folding accompanied regional metamorphism, migmatization and 

extensive granitization and gneissification which produced syntectonic granites and homogeneous gneisses [3]. The 

lithologies in the studied area are highly weathered making it difficult to identify minerals and possible geologic 

structures that could be used to determine the geologic history as well as collection of fresh rock samples.  

Several geoscientists have worked in the study area and similar areas, some of which are; Rahaman [4], Grant 

[5], Anifowose and Borode [6] amongst others giving account of the geology of the area. Anifowose, et al. [7] noted 

that joints ranging from minor to larger ones are found in all the rock types. Some of them are filled with quartz, 

feldspar, or a combination of both. They lie generally in the NW-SE direction with minor variation in NNE-SSW and 

NE-SW direction, while Boesse and Ocan [8] reported that the basement complex of south western Nigeria has been 

affected by three phases of deformation namely D1, D2, D3. The first phase D1 produced tight to isoclinal folds, 

followed by the second phase D2 which is characterized by more open folds of variable styles and large vertical 

NNE-SSN trending faults. Okunlola and Jimba [9] carried out petrographic and geochemical evaluation of pegmatite 

bodies around Aramoko, Ara and Ijero area and concluded that majority of the samples are lepidolite sub class while 

some pegmatite bodies may have undergone mild post magmatic alteration, especially those outcropping around 

Ijero area. Caby and Boesse [10] have also indicated the presence of nappes from shallow dips of foliations, shear 

zones, low angle thrusts and associated recumbent folds in the Ife-Ilesha area. Oyinloye [11] also worked on the 

geology and geochemistry of banded and granite gneisses in Ilesha area and concluded that the elements used to 

discriminate between tectonic settings for volcanic rocks are vulnerable to metamorphic alteration. 

However, this study attempts to carry out petrographic and mineralogical studies of the various rock units through 

thin sections, using the Research Petrological Microscope under transmitted light and assess the impact of tectonic 

deformation in the study area. 

 

2. Location of the Study Area 
The studied area is situated within Ikere and its environs. It is located between latitudes 7

0  
00’N and 7º35N and  

longitudes 5º10’|E and 5º15’|E respectively covering a total area of 346.5km
2
. The mapped area is generally 

accessible with network of footpaths linking parts of the towns and to the outcrops. The settlement pattern in the area 

is nucleated and the major occupation of the inhabitants are farming and hunting (Fig.1).  

 

2.1. Local Geology of Ikere Ekiti 
Ikere- Ekiti and its environs is dominated by crystalline rocks such as migmatite-gneiss-quartzite complex, older 

granites, charnockites, fine-medium grained granite. There is close association between the charnockitic rocks and 

non-charnockitic  granitic rocks due to their field relations as explained in the geology of the basement complex 

rocks of Nigeria [12]; Rahaman [13]; [14, 15] and Hubbard [16]. The underlying rock units are as follows; 

 

2.2. Migmatite-Gneiss-Quartzite Complex 
The migmatite-gneiss-quartzite complex is the oldest of the rock types in Ikere-Ekiti. It occupies about 80% of 

the study area and appears to be undifferentiated in pattern within the area. 

 

 
Fig-1. Map of Ekiti showing the Study Area. 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

68 

 

It is characterized mostly by alternating light and dark coloured bands of minerals. The minerals are hornblende 

or biotite. According to Olarewaju [17], quartz and plagioclase feldspar constitutes large percentage of minerals in 

the migmatite while the gneiss is medium grained and strongly foliated. The quartzite occurs as ridges and range 

from massive to schistose types. The schistocity is as a result of the presence of flaky minerals such micas and 

chlorite. They have simple mineralogy with quartz occurring as one of the essential minerals in addition to biotite, 

mymakite and microcline feldspar in the rock.  
 

3. Charnockites  
 Charnockites also abound in the study area. The geological map of the area produced by Olarewaju [12] 

revealed that the charnockites occupy more than 70% of the land mass of Ikere-Ekiti. The prominent outcrops are 

found around Ikere- Ise road, comprehensive high school, Afao, Temidire Ikere- Ekiti (Fig.2). The three main 

textural types of charnockites distinguished on the field conforms with Olarewaju [18] classification and are coarse 

grained porphyritic charnockite, fine-medium grained charnockite  and fine grained charnockite. Most charnockite 

bodies in the basement complex of Ikere- Ekiti occur as low –lying outcrops in form of smooth elongated rounded 

boulders. 

 

  
Fig-2. Geological and cross-sectional map of the study area 

 

3.1. Method of Study 
The method adopted for this research includes field examination of the rocks and structures; and laboratory 

preparation of the rocks for thin sections. Grid sampling method with the aid of base map of the study area, and at a 

scale of 1:50,000 was adopted, coupled with the use of Global positioning system (GPS) for accurate geographical 

location of the various localities, and at a sampling density of one sample per 5 square km. Seventeen (17) rock 

samples were collected from the studied area, which were clearly labeled and put into sample bag to avoid mix up. 

The general trend, attitudes of the rocks were observed and measured using compass clinometer. Mega and micro 

structures such as folds, fractures, joints, veins and solution holes were also observed. All measurements were 

recorded in the field notebook and photographs of identified features on the outcrops such as joints, folds, fractures, 

xenoliths, solution cavities, tension gashes and foliations were taken. Also, the orientations of structures such as 

veins, fractures and joints were plotted and represented in rosette diagrams.  Ten (10) fresh rock samples were 

selected from the bulk samples collected and were prepared for thin sectioning in other to identify the minerals 

embedded in the rocks using standard procedures of preparation. The slides were later mounted for microscopic 

studies using the Research Petrological Microscope. 

 

4. Results 
 

Table-1. Field Data 

S/N  Location  GPS Reading  Rock type  Lithology  Texture  Structure  

1  First Baptist 

Church Ise- 

Road  

7029ʹ53.55ʹʹN  

5013ʹ50.39ʹʹE  

Metamorphic 

rock  

Migmatite  Coarse 

grained  

Foliation , 

Jointing 

fracture  

2  Iroke-Ikere  

Equity  

7029ʹ54.68ʹʹ N  

5014148.4511E  

Igneous rock  porphytic 

granite  

Medium 

grained  

Fracture 

joints  

3  Irokin, Ise- 

Road  

7029ʹ55.86ʹʹ N  

5014ʹ50.38ʹʹE  

Igneous rock  Charnockite  Medium 

grained  

Joint 

Fracture  

      Continue 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

69 

 

4  Temidire area  7029ʹ55.08ʹʹ N  

5014ʹ48.02ʹʹE  

Igneous rock  Granite  Coarse 

grained  

Fracture, 

Cracks, 

Joints  

5  Irokin, Ikere-

Ekiti  

7029ʹ56.46ʹʹ N  

5014ʹ50.57ʹʹE  

Igneous rock  Light-coloured 

granite  

Fine grained  Veins, 

Joints, 

Cracks  

6  Keepers 

Church  

Araromi 

7029ʹ59.03ʹʹ N  

5014ʹ52.21ʹʹE 

Igneous rock  Granite  Coarse 

grained  

Fault, 

Joints,  

Xenoliths  

7  Araromi Area  7029ʹ53.27ʹʹ N  

5014ʹ51.95ʹʹE  

Igneous rock  Charnockite  Fine grained  Joints, 

Cleavages  

8  State 

Specialist 

Hospital, Ise-

Equity  

7029Ꞌ42.50 ꞋꞋ N  

5015Ꞌ15.64 ꞋꞋ E  

Igneous rock  Granite  Medium 

grained  

Joint, 

Fracture  

9  Oke-Ikere  7029ʹ50.15ʹʹ N  

5013Ꞌ38.85 ꞋꞋ E  

Igneous rock  Charnockite  Medium 

grained  

Xenolith, 

Dyke  

10  Oke-Kajola  7030’18.395”N  

5013’39.66 “ E  

Igneous rock  Charnockite  Medium 

grained  

Joints, 

Xenolith, 

Solution 

cavity  

11  Oke-igbo 

Olobe  

7030’18.30 “ N  

5013’37.37 “ E  

Igneous rock  Charnockite  Medium 

grained  

Dyke, 

veins, Joint  

12  Temidire Afao  7030’14.97 “ N  

5013’35.96 “ E  

Igneous rock  Charnockite  Medium 

grained  

Dyke, vein, 

joint  

13  Oke 

Igbogbeyin  

7030’8.47 “ N  

5013’40.81”E  

Igneous rock  Charnockite  Medium 

grained  

Dyke, 

solution 

cavity ,  

14  Ijoka area  7029’33.81” N  

5013’41.55 “ E  

Igneous rock  Porphytic 

granite  

Coarse 

grained  

fracture, 

Joints  

 
Table-2. Modal analysis of the rock samples 

Minerals  S1  S2  S3  S4  S5  S6  S7  S8  S9  S10  

Quartz  58  56  70  54  60  63  68  74  65  68  

Plagioclase  15  13  10  11  12  13  8   15  8  

microcline    2 4  5     4  

Myrmekite     4  5       

Biotite  23  25  4  15  12  19  20  26  20  8  

orthoclase    5  5       3 

Opaque  4  6  3 2   5 4   7 

Hornblende     2 4  11     2  

 
Table-3. Description of Samples 

S/N Slide Rock Name Location 

1  S1  Charnockite  Araromi  

2  S2  Charnockite  Temidire Afao  

3  S3  Charnockite  Oke-kere  

4  S4  Pegmatite dyke  Oke-gbogbeyin  

5  S5  Porphyritic granite  Ijoka  

6  S6  Porphyritic granite  Araromi Ise-road  

7  S7  Fined-grained granite  State speacialist hospital  

8  S8  Coarsed-grained granite  Iroki-Ise road  

9  S9  Medium-grained granite  Ise-road  

10  S10  Fine-grained granite  Keepers church araromi  

 

 
Fig-3. Chart showing (%) concentration of minerals in various samples. 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

70 

 

 
Fig-4a. Photomicrograph of medium grained granite slide under PPL  X40 

 

 
Fig-4b. Photomicrograph of medium grained granite slide under PPL  X40 

 

 
Fig-5a. Photomicrograph of fine grained granite slide under CNL X40 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

71 

 

 
Fig-5b. Photomicrograph of fine grained granite slide under PPL X40 

 

 
Fig-7a. Photomicrograph of porphyritic granite slide under CNL X40 

 

 
Fig-7b. Photomicrograph of porphyritic granite slide under PPL X40 

B 

 

 

 

 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

72 

 

 
Fig-8a. Photomicrograph of porphyritic granite slide under CNL X40 

 

 
Fig-8b. Photomicrograph of porphyritic granite slide under PPL X40 

 

 
Fig-9a. Photomicrograph of charnockite slide  under CNL  X40 

 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

73 

 

 
Fig-9b. Photomicrograph of Charnockite under PPL X40 

 

 
Fig-10a. Photomicrograph of Charnockite slide under CNL X40 

 

 
Fig-10b. Photomicrograph of Charnockite slide under PPL X40 

 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

74 

 

 
Fig-11a. Photomicrograph of charnockite slide under CNL X40 

 

 
Fig-11b. Photomicrograph of Charnockite slide under (PPL) X40 

 

 
Fig-12a. Photomicrograph of pegmatite slide under CNL X40 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

75 

 

 
Fig-12b. Photomicrograph of pegmatite slide under PPL X40 

 

 
Fig-13a. Photomicrograph of coarse grained granite  under CNL X40 

 

 
Fig-13b. Photomicrograph of coarse grained granite under PPL X40 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

76 

 

 
Fig-14. Joint on charnockite at Araromi, Ikere 

 

 
Fig-15a. Quartz veinlet on charnockite at Oke-Ikere 

 

 
Fig-15b. Quartz vein on chrnockites at Temidire, Afao. 

 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

77 

 

 
Fig-16a. Pegmatite Dyke on Charnockite at Ijoka 

 

 
Fig-16b. Pegmatite Dyke on granitic rock at Temidire. 

 

 
Fig-17. Cross-cutting relationship between a dyke and a vein at gbogeyin 

 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

78 

 

 
Fig-18. Solution cavity on granite at Afao, Ikere-Ekiti 

 

 
Fig-19. Xenolith on granitic rock at Afao, Ikere Ekiti 

 

 
Fig-20. Exfoliation on migmatites at keepers church, Ise road, Ikere 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

79 

 

 
Fig-21. Tension gashes on charnockite at Ijoka 

 

 
Fig-22. Pinch and swell structure on charnockite at Afao 

 

 
Fig-23. Mineral Inclusions on charnockites at Oke-Ikere 

 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

80 

 

 
Fig-24. Ptygmatic Fold on charnockitic rock at Araromi. 

 

 
Fig-25. Rosette Diagram of veins in the study area 

 

 
Fig-26. Rosette diagram of Joints in the study area 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

81 

 

5. Discussion 
The result of the field data acquired is presented in Table.1. Modal analysis of the different rock samples are 

shown in Table.2, while Table. 3 presents the sample locations and the % concentration of minerals in various 

samples. The photomicrographs of the thin section from the rocks are also shown  (Figs4-13), while the photographs 

of the various structural elements  identified are presented (Figs14-24) and the rosette plots of the veins and joints in 

the study area are shown (Figs 25-26) respectively. 

 

5.1. Petrographic Description of some Prominent Minerals in the Slides 
The thin section was studied with the aid of Petrological Microscope and the slides were analyzed under plane 

polarized light and crossed nicols. 
 

5.2. Quartz (SiO2)  
The mineral quartz is colourless under the plane-polarized light, with no pleochroism, and twinning. The habit is 

subhedral to anhedral. Birefringence is also 1st order with extinction angle occurring at ~30°, 40° and 80°. Habit is 

anhedral to subhedral. Birefringence is 3rd order with extinction angle at angle ~37°, 30° and 32°. The hornblende is 

deep green, pleochroic prismatic crystals in thin section with 1st order birefringence. Twining and extinction angle 

are totally absent. 
  

5.3. Biotite (Mg,Fe)3 AlSi3O10(OH,F)2 

Biotite shows grey to brown coloration, with subhedral to anhedral habit and no twining. Birefringence is 1st 

order and the mineral possess no extinction angles. Biotite forms interstitial lamellae with brown pleochroism. 

Commonly, an inner zone of deep green hornblende is surrounded by an outer biotite and quartz; this is shown in the 

digitized sketches of the slides in (plates 1-10). Biotite has some inclusion of accessary minerals like apartite, zircon, 

rutile and mymrkite. 

  

5.4. Plagioclase Feldspars (NaAISi3O8-Ca2AI2Si2O8)  
The crystals of plagioclase are colourless in plane polarized light but exhibit first order grey colour when the 

polar is crossed. It can be distinguished from other types of feldspar because of its polysynthetic twining visible in 

the crystals. Plagioclase occurs in some slides as phenocrysts. The more prevalent twining in the plagioclase is the 

albite with an extinction angle parallel to the cleavage direction.  

 

5.5. Hornblende (Ca2(Mg,Fe)5(AI,Si)8O22(OH)2 

It appears as greenish black under plane polarized and shows pleochroism from green to brown. Under plane 

polarized light, a few hornblende crystals showed the characteristics shape and two cleavages at 120º. In crossed 

polar, twinnings were seen in a few of the hornblende crystals and the highest interference colour seen, is a second-

order blue.  
 

5.6. Interpretation of the Thin Sections 
The petrographic examinations of the thin sections revealed the various mineral distribution such as quartz, 

biotite, hornblende, opaque, mymakite and feldspar (orthoclase, plagioclase and microcline). Quartz and feldspar 

alone constitute up to 78% of the thin section. Quartz is the most abundant and dominant mineral in all the slides and 

this indicated that the rocks are products of acidic magma crystallization. Feldspar is second to quartz in abundance 

while ferro-magnesian and opaque minerals constitute the coloured minerals. This is illustrated in slide 1-10 (table 2) 

which depicts the sketches of the Precambrian rocks around Ikere-Ekiti and their mineralogical components. 

 

5.7. Q-Quartz, P-Plagioclase, B-Biotite, O-Orthoclase, Op-Opaque, M-Microcline, My-Mrmykite, 

PPL- Plane Polarized Light, CNL-Cross Nicol 

5.7.1. Rosette Diagrams 
This is a diagram that shows the direction and minor images of joints and veins. Rosette diagram are essential 

histograms into a circle to give a true angular plot. The data for plotting a rosette diagram was obtained from the 

field. Rosette diagram is aimed at displaying the direction of the dominant tectonic force responsible for the 

deformation of the outcrops. The veins and joints data obtained on the field were used in plotting the rosette 

diagrams (Figs 25&26) using Grapher and Rosetta sotwares.  

 

5.7.2. Interpretation of the Rosette Diagrams 
The structural feature observed includes veins and joints. These were measured and plotted on a rosette diagram 

and consequently used in the interpretation of the direction of the major tectonic forces or stresses that caused the 

deformation of the rock in the mapped area. The largest arc from the rosette diagram plotted represents the direction 

of the major tectonic force, so the rosette diagram of all the structures indicate a NE-SW direction and NW-SE 

direction which is an indication of the direction of dominant tectonic forces prevailing in the studied area.  
 

5.7.3. Economic Geology of the Study Area 
The economic potentials of the various lithologic units in the studied area can be used as dimension stones . 

Granites of the studied area which is composed of red potassium-rich feldspar orthoclase feldspar, white and cream-

colored plagioclase feldspar, dark and shiny flakes of biotite mica and gray irregular quartz grains of vitreous luster. 

The fact that the mineral grains are tightly interlocked gives it a greater strength and makes it a good material for 

buildings and sculptures as well as for construction purposes. The petrographic analysis has shown that quartz occur 

abundantly in the studied area and this makes quartz very useful in the silica industries, gemstone, wrist watch, floor 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

82 

 

tiles and many other compounds of commercial importance. Also, The varying colours of charnokites as seen in the 

photomicrograph (Fig.11a) explains its chances and usefulness as a dimension stones especially in the building of 

houses, tiles making, slabs and kitchen tops etc. 

 

6. Conclusion  
The petrological and mineralogical characteristics of the Precambrian rocks in Ikere Ekiti have been carried out 

and the results presented in preceeding chapters. However, the magmatic origin of the precursor rocks of Ikere-Ekiti 

area is hereby established by the following lines of evidence: 1. The intrusive nature of the rocks, which is amply 

supported by the sharp contact relationship displayed by the various granitoid bodies with the country rocks; 2. The 

presence of a more coarser crystallinity in the core than at marginal areas of each of the granitoid bodies; 3. The 

incorporations of numerous xenolithic blocks that are often associated with slight displacements and/or rotations; 4. 

The developments of myrmekitic intergrowths at the plagioclase–alkali feldspar–quartz triple junctions, which also 

suggested the relevance of late magmatic/deuteric crystallization in the evolutionary history of the rocks. 5. The 

occurrence of microcline microperthite and complete absence of antiperthitic features in all the thin sections 

examined;  

6. The parallel alignment of flaky and platy minerals in a manner that suggest control by magmatic flux. The 

presence of xenoliths in a rock body does not only indicate the magmatic character of the parent granitic rocks, but 

also give indication of the mode of emplacements of the rock. It was observed that magma could shoulder aside 

country-rocks or “roof‟ in making space for itself and in so doing is seen to be charged with xenoliths of the 

displaced country-rocks. Xenoliths are actually evidence that a rock body was emplaced by the process of stopping. 

The modes of emplacement of magmatic rocks include shouldering aside and updoming of country rocks, a 

combination of cauldron subsidence and cauldron upheaval and stoping. The granite and charnockite of Ikere-Ekiti 

area are charged with numerous xenolithic lenses, rafts and blocks of the country rocks, therefore one of the 

mechanisms of emplacement of the parent granitic rocks may have been the process of stopping; and most likely, 

piecemeal stopping. The petrographic investigation shows that a distinct boundary can be drawn between the granite 

and charnockite in the studied area based on the textures and mineralogical composition. The texture of the pegmatite 

analyzed revealed a coarse grained type which is indicative of plutonics. It cooled very slowly close to the earth 

surface which resulted in its coarseness. Also, the petrology and petrographic investigation of the study area revealed 

that quartz has the highest percentage modal composition in all the thin sections (Table.2, Fig.3). The rocks are 

characterized by the assemblages of quartz, biotite, hornblende, plagioclase, orthoclase, microcline, mymakite and 

opaque minerals. The structural features displayed on the rocks in the studied area (Figs 14-24) are manifested on the 

charnockites and granitic rocks with structures such as joints, dykes, xenoliths, veins and veinlets seen on the 

outcrops mapped. The petrographic investigation indicates that the granites consists of minerals like quartz, biotite, 

plagioclase, and microcline, charnockite consists of minerals like quartz, plagioclase, and biotite while pegmatite 

consists of minerals like quartz, plagioclase, biotite, and microcline. 

It also showed that the rocks formed in the studied area were emplaced tectonically, based on the styles and 

magnitudes of structures detected and their disposition as seen in the rosette diagrams (Figs 25&26). These structures 

are believed to be the product of the Pan-African orogeny which affected the rocks in the studied area and are 

imprints of various stages of deformation in the area. Field and petrographic characteristics confirm that the granitic 

parent rock and charnockites most likely had magmatic origin, and that one of the mechanisms of emplacement of 

the parent granitic rocks may have been the process of piecemeal stopping. Both syn-tectonic and post-tectonic 

emplacements were probably relevant in the evolutionary history of the rock unit(s). It is hoped that further research 

work on the area, including geochemical, isotopic and geothermobarometric studies, will throw more light on the 

evolutionary history and tectonic setting of the rock unit(s). 

 

6.1. Recommendation 
The detailed petrographic and mineralogical investigation of the basement rocks in Ikere-Ekiti, south-western 

Nigeria has shown that the study area belongs to the Precambrian basement complex of Nigeria. In view of the 

research conducted in the studied area, the following recommendations are proposed to improve on the present study 

such as detailed geological mapping should be carried out to discover other secondary structures of importance 

which could elucidate further the manner and styles of deformation in the study area. Further research should be 

carried out in Ikere-Ekiti in other to delineate the impact of the various deformational episodes on geodesy and 

environment.  

 

6.2. Acknowledgement 
I hereby acknowledge the contributions and technical assistance from Kenneth Chidiebere Nwosu during field 

work and data collection stages of this work.  

 

References 
[1] W. O. Kennedy, "The structural differentiation of Africa in the Pan African thermotectonic episode," University of Leeds, Research 

Institute of African Geology, 8th Annual Rep, 1965. 

[2] T. N. Clifford, The structural framework of Africa. In Clifford, T.N and Gass, I.G (eds). African magmatism and tectonics. Edinburg: 

Oliver & Boyd, 1970. 

[3] S. I. Abaa, "The structure and petrography of alkaline rocks of the mada younger granite complex, Nigeria," Journal of African Earth 

Science, vol. 3, pp. 107-113, 1983. 

[4] M. A. Rahaman, Recent advances in the study of the basement complex of Nigeria. In: OLUYIDE P.O, ET AL., (eds). Precambrian 

geology of Nigeria. Kaduna: Geological Survey of Nigeria Publication, 1988. 

[5] N. K. Grant, "Geochronology of precambrian basement rocks from Ibadan, Southwestern Nigeria," Earth and Planetary Science 

Letters, vol. 10, pp. 29-38, 1970. 

[6] A. Y. B. Anifowose and A. M. Borode, "Photogeological study of the fold structure in Okemesi Area, Southwestern Nigeria," 

Journal of Mining and Geology, vol. 43, pp. 125-130, 2007. 



Asian Review of Environmental and Earth Sciences, 2014, 1(3): 66-83 

 

 

 

 

83 

 

[7] A. Y. B. Anifowose, I. B. Odeyemi, and A. M. Borode, "The tectonic significance of the Ifewara-Zungeru megalineament in 

Nigeria," in Proceedings of the 1st International Workshop on Geodesy and Geodynamics . Centre for Geodesy and Geodynamics, 

Toro, Bauchi State Nigeria, February 9-11, 2005, 2006. 

[8] S. Boesse and O. Ocan, "Geology and evolution of the Ife-Ilesha schist belt, Southwestern Nigeria," In Benin-Nigeria Geotraverse. 

International Meeting on the Proterozoic Geology and Tectonics of High Grade Terrain. IGCP, 1992. 

[9] O. A. Okunlola and S. Jimba, "Compositional trends in relation to Ta-Nb mineralization in precambrian pegmatites of Aramoko-ara-

Ijero area, Southwestern Nigeria," Journal of Mining and Geology, vol. 42, pp. 113-126, 2006. 

[10] R. Caby and M. Boesse, "Pan African nappe system in Southwest Nigeria: The Ife-Ilesha schist belt," Journal of African Earth 

Sciences, vol. 33, pp. 211-225, 2001. 

[11] A. O. Oyinloye, "Geology, geochemistry and origin of the banded and granite gneisses in the basement complex of Ilesha area, 

Southwestern Nigeria," Nigerian Journal of African Earth Sciences, vol. 26, pp. 633-641, 1998. 

[12] V. O. Olarewaju, REE in the charnockitic and associated granitic rocks of Ado-Ekiti-Akure, Southwestern Nigeria. In: OLUYIDE 

P.O. ET AL (eds). Precambrian geology of Nigeria. Kaduna: Geological Survey of Nigeria Publications, 1988. 

[13] M. A. Rahaman, Review of the basement geology of Southwestern Nigeria. In: KOGBE, C.A. (ed). Geology of Nigeria. Lagos: 

Elizabethan Publishing Company, 1976. 

[14] P. G. Cooray, Notes on the charnockites of the Ado-Ekiti area, Western State, Nigeria. In: African geology Ibadan. (Eds). 

Dessauvage and whiteman, geology department. Nigeria: University of Ibadan, 1972. 

[15] P. G. Cooray, "Classification of charnockitic rocks of Nigeria," Journal of Mining and Geology, vol. 14, pp. 1-6, 1977. 

[16] F. H. Hubbard, "The association charnockite –older granite in Southwestern Nigeria," Journal of Mining and Geology, vol. 3, pp. 25-

32, 1968. 

[17] V. O. Olarewaju, "Geochemistry of the charnockite and granitic rocks of the basement complex around Ado Ekiti, Southwestern 

Nigeria," Unpublished Ph.D Thesis, University of London, 1981. 

[18] V. O. Olarewaju, The charnockitic intrusive of Nigeria. In OSHI (ed). The basement complex of Nigeria & its mineral resources (A 

Tribute to Prof. M.A.O Rahaman). Ibadan: Akin Jinad & Co, 2006. 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
Views and opinions expressed in this article are the views and opinions of the authors, Asian Review of Environmental and Earth Sciences shall not be 

responsible or answerable for any loss, damage or liability etc. caused in relation to/arising out of the use of the content. 

 


