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THE GEOLOGY OF BUTAWA, KAFIN MAGAJI AND THEIR ENVIRONS, PART OF SHEET 79 (MULUMFASHI) NE.

NIGERIA.

BY ADAMU BELLO SULEIMAN U12GL1032

A THESIS SUBMITED TO DEPARTMENT OF GEOLOGY, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILMENT OF THE REQUIMENTS FOR THE AWARD OF B. Sc. (HONS) DEGREE IN GEOLOGY

SEPTEMBER, 2016

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DECLARATION I ADAMU BELLO SULEIMAN with registration number U12GL1032 hereby declare that this project titled

“The Geology of Butawa, Kafin Magaji and its environs, part of sheet 79

(MULUMFASHI) NE Nigeria.” has been prepared by me and is a record of my own research work. It has not been presented in any form for the award of any degree in any other institution of higher learning. All quotations and the sources of information are indicated and duly acknowledged by means of references. Signature: _________________

Date: ___________________

Name: ADAMU BELLO SULEIMAN Registration Number: U12GL1032

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CERTIFICATION This project titled “The Geology of Butawa, Kafin Magaji and its environs, part of sheet 79 (MULUMFASHI) NE Nigeria.” is written by ADAMU BELLO SULEIMAN to meet the requiment governing the award of the degree of Bachelor of Science in Geology Department, Ahmadu Bello University, Zaria.

_______________________ Dr. I. HAMIDU Supervisor

_____________________ Date

________________________ Prof. H. Hamza Head of Department, H.O.D

_____________________ Date

_______________________ Dr. I. HAMIDU Project Coordinator

_____________________ Date

________________________ External Supervisor

_____________________ Date

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DEDICATION I dedicate this work to Almighty ALLAH (SWA).

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ACKNOWLEDGEMENT I sincerely wish to express my profound gratitude to the Almighty Allah, the author and finisher of all knowledge, wisdom and understanding, from where my help comes despite the challenges. My special appreciation goes to my supervisor, Dr I. Hamidu who was a source of inspiration to me throughout the field work. He ensures everything was done the right way, appreciation also goes to other lecturers in the Geology Department and also to my group members, I say thanks a lot for without your support, persistence and assistance no meaningful achievement would have been made. You are truly wonderful partners. My gratitude goes to my dad, Alhaji Adamu Sule and my mum, Hajiya Hauwa Adamu who sponsored my education. You are a pillar of strength, and to my siblings for their moral and financial support. My appreciation is further extended to my colleagues at school and friends, thank you for your encouragement, feedback and creative ideas. You are inspiring.

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ABSTACT An extensive 14 days field work was carried out around Kafin Magaji and its environs. The major rock types mapped are gneiss, granite gneiss and coarse grained granite with minor rocks which include pegmatites, gniess xenoliths and aplite dykes. Structural features such as joints, faults and veins were recorded and are generally trending in the N-S direction, which is interpreted to be related to the Pan-African orogeny. The gneissic rock are the oldest rock unit within the sequence in the study area and constitute firmly of similar grain size. The granites within the study area are the youngest and are mainly distinctive of a coarse grained types and as well dominates the hilly part of the study area. The pegmatites occurring as minor rock unit within the study area are granitic in composition made up of large crystal of quartz and feldspathic materials. Tectonically, the rocks are classify as volcanic arc and syn-collisional and possibly late-to- post-collisional granitic rocks with respect to the Pan-African orogeny. The geological structure observed in this area include: faults, quartz vein, folds, joints, pegmatite and foliation. The dominant structures were observed to aligned in the NE- SW direction. Water supply can be said to be fairly moderate, because most of the rivers are ephemeral consequently are dry as at the time of the field work though majority of the wells have considerable amount of water.

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Table of Contents DECLARATION ................................................................................................................................................  i   CERTIFICATION  .............................................................................................................................................  ii   DEDICATION  ................................................................................................................................................  iii   ACKNOWLEDGEMENT  .................................................................................................................................  iv   ABSTACT  .......................................................................................................................................................  v   LIST  OF  PLATES  ............................................................................................................................................  ix   LIST  TABLES  ..................................................................................................................................................  x   CHAPTER  ONE  ...............................................................................................................................................  1   GENERAL  INTRODUCTION  ........................................................................................................................  1   1.2          AIM  AND  OBJECTIVES  .....................................................................................................................  1   1.3          LOCATION  AND  ACCESSIBILITY  OF  THE  STUDY  AREA  ......................................................................  1   1.4  

TOPOGRAPHY AND  DRAINAGE  PATTERN  ....................................................................................  2  

1.5

CLIMATE  AND  VEGETATION  .......................................................................................................  2  

1.6

HUMAN GEOGRAPHY  AND  LAND  USE  ........................................................................................  3  

1.7  

SCOPE AND  METHODOLOGY  ......................................................................................................  4  

1.8

PREVIOUS WORK  ON  THE  STUDY  AREA  ......................................................................................  4  

CHAPTER TWO  ..............................................................................................................................................  7   LITERATURE  REVIEW  ................................................................................................................................  7   2.0  REGIONAL  GEOLOGY  OF  NIGERIAN  BASEMENT  COMPLEX  AND  TECTONIC  SETTING  .........................  7   2.3  REVIEW  OF  GENERAL  GEOLOGY  OF  THE  NIGERIAN  BASEMENT  COMPLEX  ....................................  9   2.3.1  MIGMATITE-­‐GNEISS  COMPLEX  ....................................................................................................  9   2.3.2  METASEDIMENT  (SCHIST  BELT)  .................................................................................................  10   2.3.3  OLDER  GRANITES  .......................................................................................................................  10   2.3.4      Volcanic  and  Hypabyssal  rocks  (Younger  Granite  series)  ........................................................  12   2.4  GEOCHRONOLOGY  ...........................................................................................................................  13   Table  1.0  Generalized  Geochronology  of  Nigerian  Basement  Complex,  source:  Grant  (1970,  1971),   Harper  et  al.,  (1973).  ..................................................................................................................................  14   CHAPTER  THREE  .........................................................................................................................................  15   3.0FIELD  GEOLOGY  AND  PETROGRAPHIC  DESCRIPTIONS  OF  ROCKS  .....................................................  15   3.1  INTRODUCTION  ............................................................................................................................  15   3.2   DESCRIPTION  OF  MAJOR  ROCK  TYPES  (LITHOLOGICAL  TYPE)  ...................................................  15   vi    


3.2.1

GNEISS ..................................................................................................................................  15  

a. .............................................................................................................................................................  15   3.2.2  COARSE  GRAINED  GRANITE  .......................................................................................................  20   3.3  

MINOR ROCK  WITHIN  THE  STUDY  AREA  ...................................................................................  25  

3.3.1    FAULT  ROCK  .............................................................................................................................  25   3.3.2      PEGMATITE  ..............................................................................................................................  26   3.3.3  VEINS  .........................................................................................................................................  26   3.3.4      XENOLITH  .................................................................................................................................  27   3.3.5     SUPERFICIAL  DEPOSITS  .........................................................................................................  28   LATERITE  .............................................................................................................................................  28   CHAPTER  FOUR  ...........................................................................................................................................  29   STRUCTURAL  GEOLOGY  AND  METAMORPHISM  IN  THE  STUDY  AREA  ...................................................  29   4.1  STRUCTURAL  FEATURES  ...................................................................................................................  29   4.2  FOLIATION  ........................................................................................................................................  29   4.3  FOLDS  ...............................................................................................................................................  30   4.4      JOINTS  .............................................................................................................................................  30   4.5  FAULTS  ..............................................................................................................................................  31   4.6  XENOLITH  .........................................................................................................................................  32   CHAPTER  5  ..................................................................................................................................................  33   ECONOMIC  GEOLOGY  AND  HYDROGEOLOGY  ........................................................................................  33   5.1  

ECONOMIC GEOLOGY  ...............................................................................................................  33  

5.1.1 LATERITE  ....................................................................................................................................  33   5.1.2     CLAY  ......................................................................................................................................  33   5.1.3  SAND  ..........................................................................................................................................  34   5.1.4   5.2  

ROCK .....................................................................................................................................  34   HYDROGEOLOGY  .......................................................................................................................  34  

5.2.1   SURFACE  WATER  ..................................................................................................................  35   5.2.2  

GROUNDWATER  ..................................................................................................................  35  

CHAPTER SIX  ...............................................................................................................................................  39   6.0  DISCUSSION,  CONCLUSION  AND  RECOMMENDATION  ....................................................................  39   6.1  

DISCUSSION ..............................................................................................................................  39  

6.2

CONCLUSION .............................................................................................................................  40   vii  


RECOMMENDATION ...............................................................................................................................  40   The aggregate rocks of the study area could serve as source of income and job creation if well exploited. The study area is characterized by many different types of trees which if the habit of afforestation is employed, the trees could serve as source for domestic fuel and construction works. The government and local authority should also try to stop indiscriminate hunting and cutting down of trees in the study area to preserve the remaining wildlife and to maintain and preserve the forestry. Hydrogeological investigation using geophysical survey method should be employed to boost productivity of water in the study area hence it will help to improve the water problems in the area both for domestic and for irrigation purposes. ....................................................................................................................................................................  40   The students should be provided with more field equipment such as GPS, compass clinometers to address the problem of shortage of equipment, this will enhance a better mapping and save time on field. Also, the orientation of students by the supervisors (departmental staff) prior to the field mapping gives insight on what is expected of the students on field and helps students to relate theoretical knowledge with field experience. Hence,will make them good geologist. Therefore, this should be maintained.  .......................  41   REFERENCE  .................................................................................................................................................  42   APPENDIX  1  ................................................................................................................................................  43   APPENDIX  2  ................................................................................................................................................  45    

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LIST OF PLATES Plate 1:  Outcrop of Gniess in the study area ……………………………………………………………………..16   Plate  2:  Photomicrograph  of  Gniess  under  XPL  and  PPL……………………………..………………………….20   Plate  3:  Outcrop  of  coarse  grained  granite  in  the  study  area…………………………………….……………21   Plate  4:  Photomicrograph  of  coarse  grained  granite……………………………………………………………….24   Plate  5:  Exposure  of  fault  rock  in  the  study  area………………………………………………………………………16   Plate  6:  Photograph  of  pegmatite  dyke  …………………………………………………………………………………..26   Plate  7:  Photograph  of  quartz  vein  ……………………………………………………………………………………......27   Plate  8:  Photograph  of  gaping  joints………………………..………………………………………………………………30   Plate  9:  Photograph  of  dextral  fault…………..…………………………………………………………………………….31   Plate  10:  Photograph  of  xenoliths…………………………………………………….……………………………………..32   Plate  11:  Local  brick  blocks  in  the  study  area……………………………………………………………………………34   Plate  12:  Photograph  of  a  hand  dug  well  in  the  study  area…………….………………………………………..36  

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LIST TABLES Table 1.0: Generalization Geochoronology of the Nigerian Basement Complex, source; Grant(1970, 1971) , Harper et, al (1973)……………………………………………………14 Table 2.0: Average modal analysis of Gniess……………………………………………..17 Table 3.0: Average modal analysis of Coarse Grained Granite……………………………22 Table 4.0: Well inventory and groundwater level in wells in the mapped area……………38

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CHAPTER ONE GENERAL INTRODUCTION 1.2

AIM AND OBJECTIVES The aim of this project work was to carryout detailed geologic mapping of the area.

Which can be achieved through the following objectives; Identify the various rock types possible mineralization, their mode of occurrence in field and structural relationship, petrography, hydrogeology, geological history. Also to have the concrete knowledge on Nigeria basement complex.This field work entails locating, mapping and sampling of outcrops and producing a geological map, which is partial fulfilment of the requirements of the award of Bachelor of Science degree in geology. other objectives of this project work is to present techniques involves in detailed geological field mapping exercise, interpretation as well as writing of scientific reports which will be of benefits to the student. In addition to preparing the much needed geological map of the study area at 1:25,000 scale.

1.3

LOCATION AND ACCESSIBILITY OF THE STUDY AREA

The area mapped falls between latitude N110 53’ 42.9” to N110 58’ 6.9” and longitude 70 57’ 13.7” to 80 00’ 00” (fig1) part of MULUMFASHI SHEET 79 NE. It covers a total of about 40 square kilometre (km2). It was geologically mapped on a scale of 1:25000. The area is located in Kano State Nigeria. The area is accessible by a major road that cut across the study area, which lead to Gwarzo L.G.A Kano state to the west and to Husure town to the east of the study area. 1  


Another major road from Gwarzo passes through the northeastern part of the study area through Ungwan Bawo to Pagwe Shanono town. Networks of footpaths which makes it possible to access the settlements located in the study area such as Salahawa, Hayin Murabus, Kanya Gurgu, Kafin Magaji, Yartaya, Riji, Butawa, and Zango.

1.4

TOPOGRAPHY AND DRAINAGE PATTERN

The topography of the area reflects the geology of the underlying rock. Some areas were observed to be hilly with gentle slope which is due to weathering and erosion. The general topographic relief of the study area is undulating with alternating massive hilly and low lying fragmented outcrops which are seen at various locations. The reliefs are of two types i.e. highland and lowland. Most of the rivers and streams found in the area are seasonal and both the drainage and hydrogeology of the area are influence by climate, rock structures and human activities. The drainage is topographically controlled. Erosional features such as gullies which the lithologies are sometimes found along the river channel.

1.5

CLIMATE AND VEGETATION

The area falls within the Tropical Continental Climatic Zone; with two distinct seasons: dry and wet seasons. This climatic zone is characterized by sultry conditions during the dry season. Rainfall lasts for five months from May to September, with an annual average of about 835mm (Morgan, 1983). The relative humidity is frequently below 10% at midday while insulations and radiation are intense resulting in large daily range of temperatures. Maximum temperatures are very high (>40oC), and minimum temperatures are very low (21oC). 2 The dry season lasts for about seven months from October-April and is characterized by dismal range of temperatures and extreme dryness. This brings a succession of Study sharp contrast. The area falls within the Sudan 2   


Savannah Vegetation type. The trees have small leaves or leaflet and thorns, such as the Acacia Specie that is characteristics of dry conditions, grasses are shorter and slender. Bush stunted trees and shrubs are very common near water courses. Natural vegetation covers less than 5% of the land area and even then degraded. Common species include Adansonia digitata(Kuka), Diospyros mespiliformis(Kanya) and tamarindus indica(tsamiya) provide edible fruits while moringa oleifera(zogale)

provide

edible

leaves.

Others

include

parkia

clappertoniana(dorawa),leiocarpus(marke) and khaya segalensis(madaci) are popular fuel wood species. During the dry season; the grasses turn yellow and the trees shade their leaves. The land is extensively cultivated mainly during the wet season and a little irrigation farming in the dry season. Rearing of animals is also another land utilization activity observed in the area.

1.6

HUMAN GEOGRAPHY AND LAND USE

The area mapped is sparsely to moderately populated. The area is inhabited by the Hausa speaking people and the nomadic Fulani, The Hausas live in small villages while the Fulani live in isolated compounds that are scattered within the study area. The villages are sparsely populated with a disperse settlement pattern. The houses are far from each other by farmlands separating one family from another while some others are scattered in form of hamlets. The main soil type in the study area is lateritic and sandy along the river channels and banks. The soil cover in the area is suitable for agricultural activities. Human activities are mainly agricultural, generally involving annual crops and livestock production (animal husbandry). The land is intensively used for cultivation of food crops like guinea corn, millet, maize, and vegetables. The soil also provides good grazing grasses for cattle and sheep. Most of the farm activities are done

3   


along the river channels. lateritic soil is used for making of bricks for construction of houses by the locals.

1.7

SCOPE AND METHODOLOGY The geological mapping of the area involved the study and identification of different rock

types and identify structures on these rocks and their mineralogical composition. With the information gathered, the geological map of the study area is produced. These are portrayed on a base map on a scale of 1:25,000, which forms part of Mulumfashi sheet 79 NE. The technique of the mapping exercise involved traversing along footpaths and dry river channels to locate outcrops; pacing round and across the outcrops to measure their dimensions. The compass- clinometers was used to determine the strikes and dips of outcrops and structural features like veins, joints, and dyke. Also, it was used to take bearings, directions. The Global Positioning System (GPS) was used to locate the actual position of the outcrops, hand dug wells and borehole with their respective elevations above mean sea level. Using the hand lens, the sizes, shapes and proportions of individual mineral grains in the rocks were described. The measuring tape was used to measure the depth to water level in open wells and the length and width of some structural features. Photographs of Some of these features were taken. With the aid of a geological hammer, fresh samples were collected, labeled and kept in a sample bag for further study. The report of each day activities were all recorded in a field note book. The geological mapping lasted from 18th April to 1th of May, 2016.

1.8

PREVIOUS WORK ON THE STUDY AREA The basement complex of Nigeria, has been studied by various workers such as Falconer

(1911), Truswell (1962), Turner (1971), and Ajibade et al. (1987). The earliest study was done by 4   


Falconer (1911) during which he introduced and distinguished between the Younger Granites and the Older Granites.

Truswell (1962) studied the geology of the crystalline basement of the

northwestern Nigeria and gave a review of the petrography and distribution of the various rock types in the area. McCurry (1971) carried out a reconnaissance survey and mapped part of the Basement Complex of Nigeria on a scale of 1:100,000 based mainly on photo geological interpretation and selected traverses. She postulated that the rocks in the area belong to the Basement Complex of Nigeria and are Precambrian to Early Paleozoic in age. She classified the rocks into three groups namely; a crystalline complex of gneisses, migmatite, and remnants of an ancient metasedimentary sequence (felspathic, quartzites) which constitute the oldest rocks. Ajibade (1976) gave classification and correlation of the Basement complex of Nigeria. The three classifications goes as follow 1.

Migmatite-gneiss complex

2.

Metasediment

3.

Older Granite A late Proterozoic sequence of sediment folded and metamorphosed into synclinoral belt

within the crystalline complex and metamorphosed to phyllites, quartzites, pelitic and psammitic schists and calcareous rocks of low to medium metamorphic grade (Green-schist facies) (McCurry, 1971).

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Figure 4.0 A Geological map of Nigeria showing Basement Complex and sedimentary areas (after Obaje et al 2006).

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CHAPTER TWO LITERATURE REVIEW 2.0 REGIONAL GEOLOGY OF NIGERIAN BASEMENT COMPLEX AND TECTONIC SETTING The rocks observed in the study area are typical of the Nigerian Basement Complex which falls within the Pan African mobile belt. The Pan African mobile belt evolved by plate tectonics processes which involves the collision between the passive continental margin of the West African Craton and the active continental margin of the Tuareg Shield (Pharusian Belt) about 600 Ma ago. The collision at the plate margin is believed to have led to the reactivation of the internal region of the belt. The Nigerian Basement Complex lied in the reactivated part of the belt (Togo-BeninNigeria Shield) aggregation. Radiometric dating indicates that the Nigerian Basement Complex is polycyclic and Include rocks of various orogenic events shown in Table 2.1. The Nigerian Basement Complex forms the southern part of the Trans-Saharan mobile belt (Caby, 1989) of Neo-proterozoic (750-500 Ma) age situated between the ArcheanPaleoproterozoic blocks of the West African Craton in the west, the Congo Craton in the southeast and the East Saharan block in the northeast (Figure5). The Nigerian Basement Complex comprises gneisses, migmatites and supracrustal sequences which have yielded relict Archean, Paleoproterozoic, as well as Neoproterozoic ages (Oversby, 1975; Rahaman, Emofurieta, and Caen Vachette, 1983; Annor, 1995; Dada, 1998; Dada, Briqueu, and Birck, 1998; Ekwueme and Kroner, 1993; Ferre, Caby, Peucat, Capdevilla, and Monie, 1998).

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The Neoproterozoic (Pan-African) orogenic imprints in the Nigerian Basement Complex were characterized by high grade metamorphism, folding, faulting and widespread granite plutonism. These granitic rocks termed the “Older Granites” in Nigeria have been dated severally at 750-500 Ma (van Breemen, Pidgeon, and Bowden, 1977; Rahaman et al., 1983; Fitches, Ajibade, Egbuniwe, Holt, and Wight, 1985; Ferre et al., 1998; Ekwueme and Kroner, 1998). Granite magmatism is commonly associated with several tectonic settings and various stages during orogenic evolution (Pitcher, 1983; Pearce, Harris, and Tindle, 1984; Whalen, Currie, and Chappell, 1987; Maniar & Piccoli, 1989; C. Frost, B. Frost, Chamberlain, and Edwards, 1999).

                   Figure5: Tectonic setting of Nigerian Basement Complex (After Ferre et al; 2002).

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2.3 REVIEW OF GENERAL GEOLOGY OF THE NIGERIAN BASEMENT COMPLEX Northern Nigeria is underlain by gneisses, migmatites and meta-sediments of Precambrian age which have been intruded by a series of granitic rocks of Late Precambrian to Lower Palaeozoic age. These rocks have been variably metamorphosed and granitised through at least two tectono-metamorphic cycles so that they have been largely converted to migmatites and granitic-gneiss (McCurry 1971).

2.3.1 MIGMATITE-GNEISS COMPLEX The gneisses and the migmatites with entrained supracrustal relics, their metamorphism is generally in the amphiblolites facies grade. These rocks are mainly quartzites, amphibolites, calcareous rocks, biotite-hornblende gneisses, quartz schist and biotite-hornblende schist. Three main components of the migmatite-gneiss complex have been distinguished (Black, 1980). These include: (a)

A grey foliated biotite and biotite-hornblende-quartzo-feldspathic gneiss.

(b)

Basic schist.

(c)

Basic schist with felsic components (the felsic components here are represented by granitegneiss, pegmatite and aplite). These rocks may not however, be represented in a single rock type of migmatite-gneiss.

Many workers proposed that the rocks of the basement complex of Nigeria are mainly of sedimentary origin with associated igneous rocks, which have been variably altered by granitisation, migmatisation and metamorphism.The gneisses and migmatites represent the oldest rocks in the Basement complex of Nigeria. However, Ajibade et al. (1987) and Rahaman (1988) have shown that there are at least two generations of migmatite-gneiss within the basement complex 9   


of Nigeria. Isotopic ages ranging from Liberian (2,500 Ma) to Pan-African (600 ± 150 Ma) have been determined from the migmatite-gneiss. Pan-African ages have been interpreted as due to rehomogenization of the pre-existing rocks during the Pan-African orogeny.

2.3.2 METASEDIMENT (SCHIST BELT) The schist belts are composed of low-medium grade, deformed, supracrustal assemblages whose metamorphism is in the green schist facies. The belts are considered to be of the upper proteroizoic rocks which have been infolded into the migmatite gneiss complex. The schists form a narrow belt which generally occupies the north-south trending synformal trough that are well developed and are made up of pelitic and semi-pelitic schist and phyllites, quartzites, conglomerates, iron formations, marbles, calc-silicate rocks and subordinate meta- igneous rocks (Adekoya, 1996). These diverse rocks types occur in varying proportions in the different belts. Ajibade (1976) and Turner (1983) attempted a provisional classification and correlation of the schist belt of northwestern Nigeria and identified ten main schist belts, which are considered to have been laid down contemporaneously on the migmatite-gneiss complex. The schist belts are the Birnin-Gwari schist belt, Kushaka schist belt, Wonaka schist belt, Anka metaconglomerate schist belt, Karau-Karau schist belt, Zungeru psammite formation, Zuru schist belt, Maru schist belt, Ushama schist belt, and Kazaure schist belt. The bulk of the rocks in the belt are pelites, semipelites, and greywackes (Rahaman, 1976).

2.3.3 OLDER GRANITES The Older Granites are the youngest of the three main rock types forming the Precambrian to lower Palaeozoic rocks of the Basement Complex of Nigeria. They occur as distinct plutons often of batholithic dimension. They are considered as syntectonic to late tectonic Pan–African granitiods. They intrude both the migmatite gneiss complex and the schist belts. Earlier granitiods 10  


are calc-alkaline granodiorite intrusions, while the later underformed post tectonic intrusions are monzonitic, sub alkaline to alkaline in character McCurry, 1989. Other rock varieties are: diorites, gabbros, charnokites and late tectonic high level volcanic and hypabysal rocks. The Older Granites normally form large plutons of batholithic sizes extending in N-S direction, an example of which is the Zaria Batholith. The Zaria granitic batholith belongs to a suite of syn and late tectonic granites and the granodiorite that marked the intrusive phase of the late Precambrian to lower Paleaozoic Pan African Orogeny in Nigeria (McCurry, 1973). These granites and granodioirite intrudes the low grade metasediments and gniesses and were collectively called the older granites to distinguish them from the Mesozioc Younger Granites (Falconer 1911) of the Jos Plateau and surrounding area. The Older Granite plutons of the mapped area are regarded as part of a single batholith, extending in a north-south direction for at least 90 Km, and up to 22 Km wide. The batholith extends from Zaria southward to the vicinity of Kaduna and the name “Zaria Granite Batholith” was proposed to it by Webb (1972). Four types of granites were recognized in this batholith: (a)

A porphyritic granite characterized by closely packed elongate microcline phenocrysts, aligned in parallel fashion, and imparting a strong planar fabric to the rock. This type occurs around Zaria and to the north and west.

(b)

Another porphyritic type, but the phynocryst are equant, and not so close together. It occurs west and south-west of Wurara.

(c)

Granodiorite occur at Wurara, not veined by later granite of type (d), and also as discrete intrusion in the south-west corner of sheet 124.

(d)

Medium to coarse-grained granite, rarely porphyritic and contain xenoliths of (a)-(c).

11  


In addition, all of the above may be cut by later, fine-grained granite veins and pegmatites. The nature of the batholith’s contacts with the country rocks suggests that the granite was intruded in a liquid condition, and did not originate in situregional granitisation of gneiss Webb (1972). The Zaria Granite Batholith is a suite of syn-and late-tectonic granites and granodiorites that mark the intrusive phase of the late Precambrian to early Paleozoic orogeny in Nigeria (McCurry, 1973).

2.3.4 Volcanic and Hypabyssal rocks (Younger Granite series)

They are either partly or wholly intrusive in older granites bodies. They occur in many places in north-western and north-eastern parts of Nigeria. These rocks are believed to have been emplaced during epi-orogenic uplift and regional cooling. Rocks belonging to these group include; Andesites, Basalts and Granite porphyries.

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Figure 6: Geological map of Nigeria showing the three major rock units in the basement as well the Jurassic granites which intruded the basement (modified after Oyawoye, 1972).

2.4 GEOCHRONOLOGY Northern Nigeria is underlain by gneisses, migmatites and meta-sediments of Precambrian age which have been intruded by series of granitic rocks of late Precambrian to lower Palaeozoic ages. The oldest rocks are represented by a series of older meta-sediments and gneisses believed to be of Birrimian age and older. Table 1 below gives the geochronology of the basement complex of Nigeria.

13  


Table 1.0 Generalized Geochronology of Nigerian Basement Complex, source: Grant (1970, 1971), Harper et al., (1973). Age (ma)

Period(or epoch)

Activity

Remark

540±40

Late Pan- African

Uplift, cooling, faulting, high level magmatic activity.

650-580

Pan-African

650-580

Granitic intrution, pegmatites and aplite

Older granites

development

Magmatism

Orogenesis: deformation, metamorphism, migmatisation and reactivation of pre-

800-1000

1900±250

(Main phase)

existing rocks

Katangan

Geosynclinal deposition, intrusion of

Katangan

hypersthenes- bearing rocks

metasediments

Granites intrusion,

Eburnean granites

Eburnean

Orogenesis: folding, metamorphism and reactivation of pre-existing rocks. 2500

Birrimian

Geosynclinal deposition

Birrimian metasediments

3100-2750

Liberian Cycle

Orogenesis and metamorphism

Dada(1997)

Emplacement of granodioritic magma

3500

Dahomeyan

Crystalline basement

Dada(1997)

14  

Crustal addition


CHAPTER THREE 3.0FIELD GEOLOGY AND PETROGRAPHIC DESCRIPTIONS OF ROCKS 3.1 INTRODUCTION This chapter describes the different rock units in the mapped area in terms of there field relationship as well as the petrographic examination in hand specimen and thin section. The mapped area consists of rocks such as gneiss which cover more than 70% of the area mapped and mostly occurring along river channels and granite found at the northeastern part of the mapped area (Fig 1) and they both harbor some of intrusions such as pegmatite, quartz veins and dykes. Therefore the major rock types are Gneiss (which is found along river channel) and coarse grained granite while the minor rock types are, fault rock, Pegmatite, Vein and xenolith. These rocks are described below from field appearance and hand sample observations aided by a hand lens; also further study were established from a microscopic observation on thin section slide with the aid of a polarizing microscope to establish their mineralogical composition and abundance to ascertain their classification.

3.2

DESCRIPTION OF MAJOR ROCK TYPES (LITHOLOGICAL TYPE)

3.2.1 GNEISS a.

Field Description Outcrop of gneisses exposure observed at northeastern part of the study area where it has

a boundary with granite. Boulders Exposures of Gneisses also occur along the south eastern part where it long stretch along the stream, trending in a north-south direction and foliation appear to

15  


trend north-south. In some case it is highly weathered and may be mistaken for schist. This believe to be part of migmatite complex which later intruded by older granite series.

Plate 1:  Outcrop  of  gneiss  which  is  found  along  the  river  channel  at  around  Butawa  SE  (N11°  54’  25.3  and   E07°58ʹ33.2ʺ).     b.  

Megascopic/Hand Sample  Description  of  Gneiss  

A fresh sample from an outcrop of gneiss was collected and viewed with a hand lens and without. The sample of rock is pinkish in color due to the dominance of orthoclase minerals. Texturally it is generally medium grained when fresh and becomes coarse grained when weathered. The constituent minerals are foliated, this is a reflection of re-crystallization and re-orientation of mafic

16  


and felsic minerals. The mineralogical composition of the rock includes plagioclase feldspar (5%), biotite mica (30%), quartz (10%) and orthoclase (55%). c.

Microscopic Description  of  Gneiss  (Slide  number  BB2)  

The rock is medium grained with some of the crystals having perfect boundaries. The minerals in the rock include: Microcline, Plagioclase, Orthoclase, Quartz, Biotite, and Muscovite. Table  2.0:  Average  Modal  Analysis  of  Gneiss  

Mineral

Visual Estimation %

Microcline

33

Plagioclase

8

Quartz

20

Orthoclase

26

Biotite

5

Muscovite

8

Total

100

           

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PIE CHAT  SHOWING   THE  COMPOSITION  OF   MINERAL   IN  GNEISS  SAMPLE   Microcline Plagioclase Quartz Orthoclase Biotite muscovite

Microcline:

It occurs as anhedral – subhedral crystals, low relief, no pleochroism and a good cleavage, thus it shows a sign of incipient alteration giving it a sort of roughly scratchy appearance in plane polarized light. In cross polarized light (XPL) the microcline below display cross-hartched twinning while others display wavey/spindly appearance,

it’s white to gray, low

birefringence with normal or undulose extinction. It constitutes about 33% of the entire mineral composition of the viewed sample of the rock. Plagioclase:

It constitutes about 26% of the entire mineral composition of the rock. The plagioclase is undergoing alteration to clay (sericite) which is the type of clay responsible for the presence of brown colour observed, it occurs as anhedral crystals, low relief, poorly developed cleavage in plane polarized light (PPL). In cross polarized light (XPL) it is gray, displays albite twinning and low birefringence. 18


Quartz:

It is monocrystalline in nature. It is clear, anhedral in form, low relief, fractures, display no pleochroism and cleavage in plane polarized light. It is cloudy to light grey (weak birefringence), and exhibit a characteristics phenomenon known as undulose extinction at 360 in cross polarized light as the stage is rotated. It constitute about 20% of the total mineral present in the slide.

Orthoclase:

It occurs as anhedral crystal, colorless with low relief in plane polarized light. It is grayish, low birefringence (first order), oblique extinction and a simple carlsbad twinning in cross polarized light. It constitutes about 26% of the entire mineralogy observed in the slide.

Biotite Mica:

This mineral is strongly pleochroic in shades of brown to dark brown, as the stage is turn with no sign of alteration, it has a good cleavage, which is anhedral to subhedral in form with moderate relief in plane polarized light. It displays a near parallel extinction and exhibits a high birefringence in cross polarized light. It occurs in traces; occupy about 5% of the entire mineral composition of the rock.

Accessory minerals: Sericite (altered microcline) and perthite are also observed on the thin section. Some minerals are also observed to be opaque both under plane and crossed polarized light. Muscovite:

It occurs as euhedral crystal, colorless, perfect cleavage with low relief, no pleochroism in plane polarized light. It is pale gray to red brown, high birefringence in cross polarized light. It occurs in traces; occupy about 8% of the entire mineral composition of the rock.

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Plate 2: (Slide no BB2): Photomicrograph of Gneiss under plane polarized light (PPL) and cross polarized light (XPL) dominantly composed of M – Microcline, P –Plagioclase, O – Orthoclase, Q – Quartz, B – Biotite, Mu – Muscovite.

3.2.2 COARSE GRAINED GRANITE a.

Field Description  

The outcrop occupies 25% of the study area; the general trend is basically north-south of area mapped. An elevated ridge of granite of about 12m and more are widely distributed in the area constituting granitic rocks which are characterize by orthogonal jointing consequently distributing boulders of granite within the mapped area. Also within the outcrop of granite are network of joints (filled, unfilled and cross cutting joint); other types of structure and intrusion observed within the granite are fault, veins and xenoliths. So also within the granite outcrop are wide mostly of pegmatite mostly simple type are encountered. Mineralogical composition of the granite include basically quartz, alkali feldspar, plagioclase feldspar and mica minerals biotite and muscovite According to the distribution of grain size within the granite outcrop; granite observed in the mapped area are medium grain. 20  


Plate 3: A coarse grained granite which comprise of various types of joint located northeast of the area mapped (11057’59.1’’ and 07058’7.3’’)

b.

Megascopic Description  of  Coarse  grained  Granite  

The rock is light-coloured due to dominance of felsic mineral. In terms of its mineral content is called a granite, and consists of pinkish feldspar (40%), quartz (30%), flaky black biotite mica (20%) and dark gray plagioclase feldspar (10%) estimated from a fresh hand sample. The texture is of cause porphyritic. c.  Microscopic  Description  of  Medium  grained  granite  (Slide  number  S1)  

Generally granitic rocks in the mapped area constitute almost similar mineralogical composition; therefore the microscopic study of the medium grained type with individual

21  


phenocryst mineral grain been well developed. The minerals in the rock include: Microcline, Olivene, Orthoclase, Quartz, and Biotite. Table 3.0:  Average  Modal  Analysis  of  coarse  grained  granite.  

Mineral

Visual Estimation %

Microcline

7

Olivine

10

Orthoclase

40

Quartz

27

Biotite

10

Fluorite(accessory)

6

Total

100

22  


Pie chart  showing  mineral  present  in  Coarse   grained  granite Microcline Olivine Orthoclase Quartz Biotite Fluorite

Biotite:

It appeared as brown colour mineral with prismatic shape and perfect cleavage. It has moderate relief, anhedral-subhedral inform and moderately pleochroic under plane polarized light. It shows interference colour from brown to green. The mineral constitute 10% of slide

Microcline:

It appear as colourless in plane polarized light, anhedral crystals, broken surface with cross-hatched twinning under cross polarized light. It has a grey colour, low relief and weak birefringence. It makes up 7% of the entire slide.

Orthoclase:

The most abundant, orthoclase appear as red colour mineral with one directional cleavage shows twinning by exolution, the line shows orthoclase changing to plagioclase under cross polarized light. Anhedral to subhedral form. It makes about 40% of the slide

Quartz:

It is mono-crystalline in nature. It is clear, anhedral in form, low relief, fractures, display no pleochroism, alteration and cleavage in plane polarized 23


light. It is cloudy to light grey (weak birefringence), and exhibit a characteristics phenomenon known as undulose extinction in cross polarized light. It constitute about 27% of the total mineral present in the slide. Olivine:

Highest temperature mineral found in granite, it makes up 13% of the rock which is greenish in colour, plochroic and it shows alteration at the edge appear colourless under plane polarized light.

Fluorite:

The accessory mineral found which appear black (opaque) both in cross polarized light and plane polarized light. A

B

                   

Plate4 A & B (Slide no S1): Photomicrographs of Coarse grained granite under (a)plane polarized light (PPL) and (b)cross polarized light (XPL) M – Microcline, O – Orthoclase, Q – Quartz and B – Biotite.

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3.3

MINOR ROCK WITHIN THE STUDY AREA

This deals  with  description  of  Bodies  of  rock  whose  names  are  based  on  their  size  and  shapes,  as  well  as   their  relationship  to  surrounding  rocks.  They  are  usually  emplaced  during  or  after  the  formation  of  the   original  host/country  rock.  In  the  study  area  fine  grained  granite  and  fault  rocks  are  among  the  minor   lithologies.  And  also  veins  and  pegmatite  dyke  are  the  only  forms  of  intrusion  in  the  area  which  are   found  to  be  younger  than  the  parent  rock  with  the  exception  of  xenolith  which  are  older.    

3.3.1 FAULT ROCK          The   fault   rock   in   form   of   a   low   lying   body   (probably   mylonite)   occurs   as   a   tectonically   deformed  rock,  probably  derived  from  the  crystallizing  silica  and  lots  of  epidote  veins  and  jointing   found  along  the  slicking  sides.  Fault  Rocks  are  indication  of  a  fault  zone  nearby  and  a  little  is  seen   around   the   northestern   part   of   the   study   area.   Texturally   it   is   fine   grained   which   composed   mainly  of  light  colour  minerals.  They  are  usually  light  brown  or  brownish-­‐red  in  colour.  

Plate 5:  fault  rock  (mylonite)  located  east  of  Ungwan  Bawo  at  N110  57’30.8’’,  E0070  59’0.5’’

25  


3.3.2 PEGMATITE This is a very coarse grained igneous rock with phenocryst of about 2cm and above in length, usually granitic in composition and typically forms during the final stages of magma chamber crystallization. It occurs widely in the study area as a surface phenomenon found on the coarse granitic rock. The mineralogy of the pegmatites is essentially large crystals quartz and orthoclase feldspars with little mica.

 

Plate  6:  Outcrop  of  granite  showing  pegmatite  dyke  at  located  west  of  Ungwan  Bawo  at  N110   54’ 16.8” E0070  59’ 49.2”  

3.3.3 VEINS Veins are minor rock types in the study area. They are usually younger than the host rock and either quartz/quartzite or quartzo-feldspartic in composition ( formed as a result of recrystallization of silicate grain in the rock crevices/joint which are being filled with hydrothermal fluid which is mainly quartz and feldspar and later solidifying). Some of the vein serves as marker

26  


bed in fault plane. This structure  was  mapped  in  some  of  the  outcrop  visited  in  study  area.  Trends   of  veins  where  recorded  and  the  major  stress  are  in  the  NE-­‐SW  direction  which  is  in  conformity   with  the  Pan  African  Orogeny.  (Appendix1).  

Plate  7:  Outcrop  of  granite  showing  quartz  vein  located  east  of  Ungwan  Bawo  at  N110  57’  59.1’’   E070  58’  7.3’’  

3.3.4 XENOLITH                              Xenoliths  are  the  inclusion  of  pre-­‐existing  rock  found  in  the  younger  outcrop.  They  

are remnants  of  the  country  rock  or  fragment  of  an  earlier  solidified  portion  having  a  different   composition.  Xenoliths  found  in  the  study  area  trending  NNE-­‐SSW.  Xenoliths  are  observed  on   major  outcrop  (granite)  in  the  study  area  (plate  10).    

27  


3.3.5 SUPERFICIAL DEPOSITS

Superficial deposits in the area include widespread laterite, alluvium deposit and soil cover which formed as products of weathering of the basement rocks.

LATERITE

This is a residual deposit found in-situ. It consists essentially of hydrated iron oxide, silica, alumina and manganese. They are reddish brown in colour, formed within coarse grained granite in the mapped area. Fig1.

b.

ALLUVIUM DEPOSITS  

Alluvial deposit are deposits of resistant minerals (resistates) which are derived from mechanical breakdown (weathering) of rocks, transported and deposited by water. In the study area, the alluvial deposits are found along streams and river channels, they are products of weathering and erosion of the basement rocks. Large chunks of alluvial deposit were observed along the river channels where trucks come to fetch sand. This sand is used for building purposes, especially in the mould of blocks and as fine aggregate in concrete as observed in all the mapped area, it is also used in plastering of houses when mixed with cement.

28  


CHAPTER FOUR STRUCTURAL GEOLOGY AND METAMORPHISM IN THE STUDY AREA Regional metamorphism was one of these events that accompanied the Pan-African deformation (Abaa, 1983).This has resulted in the formation of structures such as faulting and fracturing (Olayinka, 1992), folding, jointing, veins, intrusions, foliation and mineral lineation. This chapter describe, spatial representation, and analysis of foliations, joints and veins structures measured in the study area. The different ways of presenting such information are Rosette diagram, line diagram, point diagram and stereographic plotting. Rosette diagram is used here to evaluate the portion of the tectonic forces that affected rocks in the study area and characterize the extent of the deformation.

4.1 STRUCTURAL FEATURES Both ductile and brittle deformational structures have been mapped in the study area. Ductile structures include foliations and folds while the brittle structures include joints and faults.

4.2 FOLIATION This can be described as a planar arrangement or orientation of mafic minerals and felsic minerals into a distinct band.  Foliation in the study area is observed in banded gneiss and is defined by alternating quartz-feldspathic materials and biotite flakes. Most of the foliation strikes NNE – SSW and follow the general tectonic North -South trend. Foliation of rocks is tectonically controlled and occurs mostly in metamorphic rocks.

29  


4.3 FOLDS Folds are not well developed in the area, as the one observed to occur in the granite outcrop. The folds are displayed by pegmatite veins which occur as discordant E-W trending intrusion into the coarse grained granite towards the NE part of the study area.

4.4 JOINTS Joints are abundant structural features observed in the field. They have been observed in most of the exposures, but the granitic rocks displayed a comprehensive jointing pattern with a NNE – SSW trend. Some of the joints were mapped cross-cutting each other showing that they are formed from different orogenic events. According to McCurry, (1971) and Danbatta, (1999) the joints often result from contraction on cooling and are believed to be associated with a single episode of cooling and fracturing during epirogenic uplift.

Plate 8: Photograph showing the occurrence of gaping joint in granite exposures (Location: N110 57' 45.8" and E070 58' 41.6"). 30  


The rose diagram of joints within the study area indicate that the major stress is in the North – South direction while the minimum stress is in the East – West direction which conform to the Pan African Orogeny. (Appendix 2)

4.5 FAULTS Faults are brittle fractures within crustal rocks along which relative movement or displacement has taken place on either side of the plane. They are, thus planes of shear failure as a result of brittle fracture.There are two main categories of faults; a.   Dextral fault, this is typical fault identified if the block on the side of the fault opposite to the observer appears to have moved to the right.

Plate 9: photograph showing dextral Fault on a granite exposure located at N110 57’58.7’’ E070 58’32.5’’ b. Sinistral fault, is a strike slip fault which appears if the block has apparently moved to the left, the displacement is left-side. Faults in the study area are not well exposed but their effects on rocks and some quartz veins have been documented. Minor localized faults were observed in few localities such as

31  


displacement of Quartz veins that are more of sinistral than dextral. Some of the rivers and streams in the area are possibly flowing along the fault planes.

4.6 XENOLITH Xenoliths of lensoidal shape occur mainly in the coarse grained granite. They range from few centimeters to about 40 cm and a width of few centimeters to about 15 cm. The xenoliths show a general trend of NNE-SSW. Below is  a  picture  of  xenolith  observed  on  the  coarse  grained  Pan   Africa  granite  with  xenoliths  dark  in  colour.    

Plate 10:  Photograph  of  Xenolith  of  Gneiss  on  coarse  grained  granite  located  west  of  Gutawa  at     N110  57’  59.1’’    E070  58’  7.3’’      

32  


CHAPTER 5 ECONOMIC GEOLOGY AND HYDROGEOLOGY 5.1

ECONOMIC GEOLOGY This deals with the economic importance of geological materials mapped within the study

area. In this study area crystalline rock in form of granite, pegmatite, vein, laterite and alluvial deposits are mapped to be of economic value. The economic importance of these rocks is discussed below. 5.1.1 LATERITE This is the product of chemical weathering of rocks. In the study area, it resulted from the weathering of in-situ parent rock, essentially when the parent rock is rich in iron. This laterite can be used in construction works such as road construction and filling of foundations. Laterite could also be smelted locally for iron production, but the iron ore content is low for commercial exploitation. In the study area, laterite is used locally in making bricks blocks which are used in building local houses in the mapped area. 5.1.2 CLAY Clays are formed in-situ due to chemical weathering of the parent rocks mainly those rich in alumina-silicate minerals. Clay is plastic when wet but becomes hard when dry. This property of clay has been used in making domestic clay and ceramic products such as cooking wares, pots and water jars. It is also used locally for molding bricks for construction as witnessed in some area.

33   


Plate 11:  local  Brick  Blocks  made  from  clay  Located  at  Butawa  (11025’19.8”N  and  07058’5.3”)     5.1.3 SAND Sand could be obtained in large quantities along river and stream channels. Sand can be put to use in the construction industry. A major area where this is observed was along major stream channel. 5.1.4 ROCK It is useful as aggregate materials in construction of roads, houses, embankment or even foundation materials. It can also be put to use in construction of bridges, railway tracts and dams.

5.2

HYDROGEOLOGY Water supply in the mapped area is adequate because almost all the wells mapped as at the

time of this fieldwork had water in reasonable amount and some of the rivers were flowing 34  


although not with large volumes of water. The hydrogeology of the area can be discussed under two subdivisions: surface water and groundwater.

5.2.1 SURFACE WATER Surface water in the area is in form of streams and rivers that flow from North South down in a dendritic manner. It is seasonal and perennial. At the time of geological mapping most of the stream and rivers are dry which confirmed them to be ephemeral. Some amount of water is retained in the shallow subsurface within the voids of alluvial sand, this also provide water for domestic use during the early part of the dry season.

5.2.2 GROUNDWATER This is water tapped mostly in well and also tapped in few hand pump boreholes in the study area. There are two major types of aquifer. These aquifers are generally underground layer of porous rock or sand that allows the movement of water between layers of non-porous rocks, gravels or fractured rocks which is contained only in the shallower subsurface; the fracture crystalline aquifer and soft overburden aquifer. The soft overburden aquifer overlies the fractured overburden aquifer. Groundwater is found in the pores of the soft overburden aquifer. In the fractured crystalline aquifer, groundwater is found in the fractures. Recharge of these aquifers is mainly by rainfall directly into the soft overburden and by diffusion into the fractured crystalline aquifer. Some of the water from the rain percolates into the deep subsurface under the influence of gravity. Some of these accumulate at the water table while some are retained within the voids of sediments in the aeration zone. The ground water inventory (Table 5) shows the aeration zones (depth to water level from surface), well elevations in meters, elevation of water in wells and their location as observed in the mapped area. Table 10 shows the well inventory and the groundwater levels in the study area. 35   


Plate 12:  Hand  dug  well  located  around  Kanyan  Gurgu  of  the  area  mapped  (table 4.0: s/no 6)                       36    


TABLE 4.0:  WELL  INVENTORY  AND  GROUNDWATER  LEVEL  IN  WELLS  IN  THE  MAPPED  AREA.  23th   of  April  to  1th  of  May  2016.   S/No

Location

Coordinate

Elevation of

Depth to water level

Elevation of

wells (masbl)

from surface (meters)

water level in well(meters)

1

Ungwar Tudu

11056’6.6”N

567.13

8.53

558.6

581.7

16.5

565.2

579.0

11.0

568.0

574.8

15.9

558.9

581.4

16.4

565.0

601.1

23.8

577.3

589.9

16.9

573

590.3

11.3

579

577.0

10.5

566.5

571.0

5.0

566.0

7057’17.3” 2

Ungwar Tudu

11056’4.4”N 7057’24.5”E

3

salihawa

11056’40.0”N 7057’56.8”E

4

5.

6.

Hayin

11056’52.1”N

Murabus

7057’58.8”E

Hayin

11057’17.2”N

Murabus

7057’47”E

Kanya Gurgu

11057’45.6”N 7057’33.9”E

7.

Yar Taya

11056’13.0N 7058’30.3”E

8.

Yar Taya

11055’39.2”N 7058’13.0”E

9

Butawa

11054’46.9”N 7057’41.8”E

10.

Butawa

11054’31.4”N 7057’53.5”E

37  


11.

Zango

11054’08.6’N

573.3

7.2

566.1

571.3

6.6

564.7

7059’37.3”E 12

zango

11054’42.5”N 7059’53.1”E

38  


CHAPTER SIX 6.0 DISCUSSION, CONCLUSION AND RECOMMENDATION 6.1

DISCUSSION Evidence from the study revealed that the mapped area is part of basement complex of

Nigeria, which has undergone metamorphism and weathering. The Basement Complex rocks underlying the mapped area include gneisses and granite which are believed to be Late Precambrian to Lower-Paleozoic age in which migmatite-gneiss complex is being intruded by coarse grained granite. The various structural features or elements that are observed in the mapped area include joints, foliations, faults and quartz vein. The NE- SW trend which represents the final imprint of the Pan-African Orogeny is the last major episode that has affected the mapped area. The granites are emplaced during the Pan-Africa Orogeny, which are older granites. The granite exposed covers about 25% of the mapped area which have undergone an intense weathering. The grain size of coarse grained with a well-developed crystal shape, having an average grain size of 2cm. The morphology of the granite are low lying whale back which elevate to approximately 12m above sea leve but undergoing weathering. Mineralogical composition includes quartz, feldspar, mica (biotite) and microcline. The gneisses covers more than 70% of the study area, they are the products of metamorphism and granitization during the Pan-African Orogeny. The gneiss is believed to result from very high grade metamorphism. The occurring of gneiss is mostly restricted to river channel and some found as xenoliths within the coarse grained granite. The minerals composed majorly of biotite, quartz and feldspar (orthoclase).

39   


6.2

CONCLUSION

Evidence from the field mapping and petro-graphic studies show that the mapped area is underlain by rocks of the undifferentiated basement complex of Nigeria as well as Older-Granite suites. The evolution of the rocks has been linked to at least three past tectonic events ranging from Archean to Pan African. Structural elements such as joints, folds, foliations etc. showing either N-S or EW trends, therefore confirms the stress direction of the Pan African orogeny. Therefore in the mapped area, it is concluded that the banded gneiss is the oldest followed by the granite and the minor intrusive respectively. They rock  types  found  in  the  study  area  in  order  of  their  increasing   age,  as  shown  in  the  Geological  map.    Fault  rock  (Tectonite)    

Youngest

Pegmatite and  vein  (Inclusion)   Coarse  porphyritic  Granite   Gneiss     Xenolith  (Metasediment)  

Oldest

RECOMMENDATION

The aggregate rocks of the study area could serve as source of income and job creation if well exploited. The study area is characterized by many different types of trees which if the habit of afforestation is employed, the trees could serve as source for domestic fuel and construction works. The government and local authority should also try to stop indiscriminate hunting and cutting down of trees in the study area to preserve the remaining wildlife and to maintain and 40  


preserve the forestry. Hydrogeological investigation using geophysical survey method should be employed to boost productivity of water in the study area hence it will help to improve the water problems in the area both for domestic and for irrigation purposes. The students should be provided with more field equipment such as GPS, compass clinometers to address the problem of shortage of equipment, this will enhance a better mapping and save time on field. Also, the orientation of students by the supervisors (departmental staff) prior to the field mapping gives insight on what is expected of the students on field and helps students to relate theoretical knowledge with field experience. Hence,will make them good geologist. Therefore, this should be maintained.

   

41  


REFERENCE Abaa, S.I. (1983): The Structure and Petrography of Alkaline Rocks of the Mada Younger Granite Complex, Nigeria. Journ. Africa Earth Science 3: pp.107-113.

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APPENDIX 1 Trends of quartz vein (in degrees) on granite exposures in the study area.

43  


0080

1480

1490

0800

0220

2120

2280

2200

0340

0680

0900

2330

550

0160

0

0560

0800

074

0

070

178

0

032

0

340

  N

(9.9)

W

E

S

Rose diagram  of  quartz  vein  trending  NE-­‐SW                  

44  

0


APPENDIX 2 Table 4: Strike of joints (in degrees) on granite exposures. 025

155

066

036

028

034

015

280

045

022

345

088

024

180

228

229

099

239

022

028

104

154

103

177

102

136

038

090

150

004

146

052

152

168

048

024

N

W

E

 

S

Rose diagram  of  pegmatite  vein  trending  NE-­‐SW  

 

45  

The geology of butawa, kafin magaji and their environs, part of sheet 79 (mulumfashi) ne  

Research work.

The geology of butawa, kafin magaji and their environs, part of sheet 79 (mulumfashi) ne  

Research work.

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