RELATIONSHIP BETWEEN GEOLOGY AND TRACE ELEMENTS STUDIES OF GRANITE AT GBALEOSU SOUTH
| Format: Ms Word | 1-5 Chapters | Table of Content|
INSTANT PROJECT MATERIAL DOWNLOAD
Study Level: BTech, BSc, BEng, BA, HND, ND or NCE
Amount: ₦2,500.00
CHAPTER ONE
INTRODUCTION
- Statement of the problem
Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy. The word “granite” comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a holocrystalline rock. Strictly speaking, granite is an igneous rock with at least 20% quartz and up to 60% alkali feldspar by volume. The term “granitic” means granite-like and is applied to granite and a group of intrusive igneous rocks with similar textures and slight variations in composition and origin. These rocks mainly consist of feldspar, quartz, mica, and amphibole minerals, which form an interlocking, somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole (often hornblende) peppering the lighter color minerals. Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is known as granite porphyry. Granite differs from granodiorite in that at least 35% of the feldspar in granite is alkali feldspar as opposed to plagioclase; it is the potassium feldspar that gives many types of granite a distinctive pink color. The extrusive igneous rock is equivalent to granite rhyolite. Granite is classified according to the QAPF for coarse grained plutonic and named according to the percentage of quartz (Harvey Blatt & Robert J. Tracy 1997).Granite is nearly always massive (lacking any internal structures), hard and tough, and therefore it has gained widespread use throughout human history, and more recently as a construction stone.
The study area lies within the Western region of Nigeria. Nigeria can broadly be subdivided into three major geological components and these are: the Basement, Granites and Sedimentary Basins (Obaje, 2009). The basement (Precambrian in age) is further subdivided into five regions on the basis of the occurrence of sedimentary basins. These are the Western Nigerian Basement, North Central Nigerian Basement, Adamawa Highland, Eastern Nigerian Basement and the Oban Massif. As discussed by Obiora et al (2009) and references cited within, the basement consists of “migmatitic gneisses, including banded varieties; the schist belts constituted by mica-schists, tremolite-schists, graphite-schists, with occasional marbles and dolomites, calc-silicate rocks, meta-conglomerates and banded iron formation (BIF) and Precambrian granites including porphyritic/porphyroblastic muscovite granites, biotite granites, hornblende-biotite granites, non-porphyritic/non-porphyroblastic granites, aplites, granodiorites, diorites, quartz diorites, syenites, quartz-enstatite granites and enstatite granites (charnockites).”
Two generations of granites can be identified and these are prominent within the basement rocks. The older granites as termed by Falconer (1911) range widely in composition and age from 750 Ma to 450 Ma (Obaje, 2009). The younger granites (Jurassic in age) are prominently distributed in the North Central Nigerian Basement and occur as ring complexes which form part of a wider province of alkaline anorogenic magmatism (Obaje., 2009). Broadly speaking, the sedimentary basins can be stratigraphically divided into formations, the older Cretaceous sedimentary basins of which the Benue Trough, Bida–, and Sokoto Basins are the most prominent. The youngest sequence is the Tertiary Sedimentary Basins of which the Chad Basin is the most prominent as well as the sedimentary sequences of the Niger Delta. The geology of the area of interest in this present study falls within the Western Nigerian Basement of which the basement rocks cover almost 100% of the total land surface in this state (Oyedokun and Igonor, 2013). The study presents the results of the characterisation of granite samples obtained from a deposit site in Gbaleosu, South Western Nigeria and focused on the geology, major elements and composition of granite.
- Aim and objectives of study
The main aim of this study is to undertake the trace elements study of granite from Gbaleosu. Other objectives of this study include:
- To produce an accurate geological map of the area.
- To identify the different rock lithologies present in the study area.
- To understand and establish the geologic history of the area.
- To analyze structural data acquired and their relevance to the current geology of the study area.
- To generally analyze the economic value of the rock lithology found in the area
- To examine and report all structural features
- Justification of study
A lot of studies have been undertaken in this area, but this study specifically aims to investigate the trace elements composed of granite from Gbaleosu the study area.
1.4 Scope and Method
This study is restricted to the relationship between geology and trace elements studies of granite at Gbaleosu south western Nigerian. Geological field mapping was undertaken in order to collect, identify and study the field occurrences of granite in Gbaleosu, the method use are the thin section preparation for petrographic analysis and sample preparation for geochemical analysis. 10 fresh rock samples which were cut into thin section will then be move further for the laboratory studies.
- Study Location and Accessibility
The study area, Gbaleosu is in Oluyole local government of south western Nigeria Oyo state, Gbaleosu is situated southeast of Ibadan in South western Nigeria which is part of the Precambrian basement complex of Nigeria, it’s bounded by latitudes 7.76’00N to 7.93’00N while the longitudes 3.54’00E to 4.00’00E within Ibadan (fig 1.1). The area is bounded by Lagunji at the Western part while Akintola ogibun is at the North eastern part. Motor cycle is the major means of transportation in Gbaleosu Community. There are minor road linking Gbaleosu with some other neighboring villages. In general the study area is easily accessible through a network of minor, major and footpath
Figure1.1: Map of south western Nigerian showing the location of study area
- Physiographic setting
Physiographic setting is the study of the features of the area which occur by certain effect of geographical factors such as drainage pattern, climate and vegetation, relief and topography.
1.6.1 Climate and vegetation
The study area falls within the tropical humid climate region where the wet and dry seasons are noticed prominently in the area. Just like any other part of the south western region of Nigeria, wet season Gbaleosu runs from march through October while dry season is between November and February. The mean maximum temperature observed is 21.42°C to 26.46°C while the annual rainfall ranged from 150 to 2500mm. Generally the vegetation of major part of southwestern Nigerian represents that of the humid forest. The vegetation of the area is similar to that of tropical rain forest where they are high tree and shrub (fig 1.2), the vegetation is characterized by the presence of thick tropical greenish forest made up of different trees and grasses e.g. pawpaw, palm tree, etc.
Fig. 1.2 Showing Ecological Map of Nigeria (CIA, 1979)
1.6.2 Relief and topography
The relief and topography of the study area is randomly an undulating feature. The eastern part of the study area has higher elevation; the upper part of the study area has elevation between 100-120m feet’s (above the mean sea level).
1.6.3 Drainage pattern
The drainage system in the area is usually marked with a proliferation of many smaller streams which are wet for some few months, especially from march to October. There is a Major River in the study area called river Omi which flow from north to the southern part of the area.
1.7 Review of Related Previous Works.
Nigeria lies approximately between longitude 40N and 150N and latitude 30E and 140E. Within the pan African mobile belt in between the west African craton in the region of late Precambrian to early Paleozoic orogenesis. The basement complex is made up of Precambrian rocks and consists of schist belts folded in them. Previous works have been carried out on a regional scale on the basement complex of Nigeria and it has been shown that this is the most abundant lithology in Nigeria such work includes, Rahaman (1988), Odeyemi (1977) and Oyawoye (1964), Grant (1978), Anifowose (2006), oyinloye (2011) among others. They gave an account of the geology of this area under a broader work.
Ejimofor et al., (1996) worked on the petrography and major element geochemistry of the basement rocks of northern Obudu area, eastern Nigeria. It was shown mineralogically that, the preference of igneous fields by the granite gneisses suggest their affinity for igneous progenitors. Elueze et al., (2004) determined the petrochemistry and petrogenesis of granite from Abeokuta area, southwestern Nigeria.
The geology of the basement complex of southwestern Nigeria Oyawoye (1964), Rahaman (19176), Odeyemi (1977) noted that the rocks in the study area show eveidence of polyphase deformation with the plutonic episode of the pan African event being the most pervasive Undeformed Acid and Basic Dykes or The minor felsic and mafic intrusives.
One of the most famous publications on the pegmatitic veins in Nigeria is that of Jacobs and Webb (1946) which identified that the pegmatites are confined to a 400km NE-SE trending belt. Recently however, Okunlola and Somorin (2006), Okunlola, (2005), Garba (2003), Okunlola and King (2003), have shown evidence that they may not be restricted to only this confine. Geochronological data from previous works (Rb – Sr whole-rock and U-Pb zircon) of Pan-African granitoids intruding the reactivated Archean to Lower Proterozoic crust of central and southwestern Nigeria show that intrusive magmatic activity in these areas lasted from at least 630 to 530 Ma (van Breemen et al., 1977; Rahaman et al., 1983; Dada et al., 1987; Matheis and Caen-Vachette, 1983; Umeji and Caen-Vachette, 1984; Akande and Reynolds, 1990). Results of the rock ages also show that pegmatites’ emplacement in the southwestern Nigeria occurred mainly after the peak of the Pan-African orogenic event in this area. Several others have carried out extensive research on geochemical and petrochemical analysis on pegmatites from southwestern Nigeria. Akintola et al (2011) examined pegmatite around Awo and concluded that the pegmatite contains accessory minerals such as tourmaline, garnet, beryl and spodumene together with some rare metals. Okunlola (2005), while studying the rare metal Ta-Nb pegmatites of Nigeria outlined seven (7) broad fields namely Kabba-Isanlu, Ijero-Aramoko, Keffi-Nasarawa, Lema- Ndeji, Oke Ogun, Ibadan- Oshogbo and Kushaka-Birnin Gwari. The Olode-Gbayo pegmatites occurrences are presumed to be members of the Ibadan-Oshogbo field occurrences. Elueze et. al. (2004) embarked on a preliminary investigation of the industrial properties of the Olode-Falansa pegmatites in southwestern Nigeria and they concluded that the pegmatites have good potential for use in refractory, glass, ceramic and construction industries. Okunlola and Jimba (2006) carried out petrographic and geochemical evaluation of pegmatite bodies around Aramoko, Ara and Ijero area and concluded that majority of the samples are subclass and magmatic pegmatite while some pegmatite may have undergone mild post-magmatic alteration distinct petrologic units especially those outcropping around Ijero area.
USE THIS MATERIALS AS A GUIDE FOR YOUR PERSONAL RESEARCH WORK (IF PROPERLY CITED)