Geology and Petrochemistry of Granitic Pegmatite in Jema’a Pegmatite Field, Kaduna State

Table of Contents

1.0 INTRODUCTION

1.1 General Statement

1.2 Statement of the Problem

1.3 Aims and Objectives of the Present Work

1.4 Scope of the Present Work

2.0 LITERATURE REVIEW

2.1 Geologic Setting

3.0 MATERIALS AND METHODS

3.1 Materials Required

3.2 Exploration Method

3.2.1 Field Methods

3.2.1.1 Sampling

3.2.2 Laboratory Methods

3.2.2.1 Field Analysis

3.2.2.2 Sample Preparation

3.2.2.3 Sample Analysis

3.3 Conceptual Model Theories

3.3.1 Past

3.3.2 The Present

4.0 RESULTS

4.1 Petrographic Studies

4.1.1 Macro and Microscopic Studies

4.1.1.1Granitoids

4.1.1.2 Host Rocks

4.1.1.3 Feldspars

4.1.1.4 Mica

4.1.1.5 Tourmaline

4.2 Geochemistry

4.2.1 Major and Minor Elements Geochemistry

4.2.1.1 Interpretations of CIPW Norm

4.2.1.2 Thomton and Turtle, (1960) Differentiation Index

4.2.1.3 Interpretation of Niggli Norm

4.2.1.4 Classification of Granites after Chappell and White (1974)

4.2.1.5 Evidence from Magmatic Experiments

4.2.2 Petrochemistry of Rare Elements Granitoids and Pegmatites

4.2.2.1 Aluminum Saturation Index (A/CNK)

4.2.2.2 Variation (wt %) of CaO – NaO – K2O in Granitoids and Pegmatites

4.2.2.3 Classification of Granitoids using Q – A – P Diagram

4.2.2.4 Variation (ppm) of Rb – Ba – Sr for Differentiation of Granitoids

4.2.3 Trace Element Geochemistry

4.2.3.1 Trace Elements

4.3 Mineral Chemistry

4.3.1 Feldspars

4.3.2 Micas

4.3.3 Tourmaline

4.4 Tectonic Setting Discrimination of the Research Area

4.4.1 Fertile Granite in Aluminum Saturation Index Diagram coded by Tectonic affiliation and Geochemical signature

4.4.2 Tectonic Classification based on SiO2 Content and K2O/Na2O ratio

4.4.3 Rb (ppm) versus Nb + Y (ppm)

4.5 Lithological and Structural Relationships

CHAPTER FIVE

5.0 DISCUSSION OF RESULTS

5.1 Granitoids

5.2 Rare Elements as Exploration Tool

5.3 Feldspars

5.4 Muscovites

5.5 Tourmalines

5.6 Petrogenesis

5.6.1 Petrogenic Model

CHAPTER SIX

6.0 CONCLUSIONS AND RECOMMENDATION

6.1 Conclusions

6.2 Recommendations

Objectives and Research Themes

This thesis aims to conduct a systematic geological and geochemical study of the granitic pegmatites within the Jema’a pegmatite field in Kaduna State, Nigeria. The central research objective is to evaluate the geological evolution, geochemical characteristics, and economic potential of these pegmatites in relation to the surrounding granitoid bodies to better understand their mineralization, particularly regarding rare-element deposits.

• Geological and geodynamic evolution of granitic pegmatites.
• Mineralogical and geochemical characterization of granitoids and pegmatites.
• Evaluation of economic mineral potential with a focus on rare-element mineralization.
• Tectonic classification and petrogenetic modeling of the research area.
• Use of rare elements as exploration tools for identifying mineralized zones.

Excerpt from the Book

Summary of Chapters

1.0 INTRODUCTION: This chapter introduces the Jema'a pegmatite field within the Nigerian pegmatite belt and outlines the scope, aims, and objectives of the research.

2.0 LITERATURE REVIEW: This section covers the regional geological setting of the Nigerian Basement complex and the tectonic framework of the Pan-African orogenic belt.

3.0 MATERIALS AND METHODS: This chapter details the field mapping, sampling, and analytical techniques (e.g., AAS, XRF, INAA) used to generate geochemical data.

4.0 RESULTS: This section presents the comprehensive petrographic and geochemical data obtained from granitoids, host rocks, and mineral separates.

5.0 DISCUSSION OF RESULTS: The chapter interprets the findings, providing insights into petrogenesis, tectonic settings, and the utility of rare elements as exploration tools.

6.0 CONCLUSIONS AND RECOMMENDATION: This final chapter synthesizes the study's conclusions regarding the pegmatite field and offers recommendations for future economic evaluation.

Keywords

Granitic Pegmatites, Jema'a Pegmatite Field, Petrochemistry, Geochemistry, Rare Elements, Fractionation, S-type Granites, Mineralization, Pan-African Orogeny, Aluminum Saturation Index, Feldspars, Muscovite, Tourmaline, Tectonics, Nigeria.

Frequently Asked Questions

What is the core focus of this research?

The research focuses on the geology and petrochemistry of granitic pegmatites in the Jema’a pegmatite field, Kaduna State, to determine their formation and mineralization potential.

Which pegmatite field is being studied?

The study is conducted in the Jema’a pegmatite field, which is the northwestern terminal point of the 400km Nigerian pegmatite belt.

What is the primary objective of the work?

The primary objective is to evaluate the economic significance of rare-element pegmatites by analyzing their mineralogical and geochemical relationships with associated granitoids.

What scientific methods were employed?

The methodology includes systematic 1:50,000 geological mapping, thin-section petrographic analysis, and geochemical analysis using Atomic Absorption Spectrometry, X-Ray Fluorescence, and Instrumental Neutron Activation Analysis.

What does the main body of the work cover?

The main body covers detailed petrochemical results, including major/trace element geochemistry, mineral chemistry of feldspars, micas, and tourmalines, and tectonic setting discrimination.

How is the research characterized by its keywords?

The research is characterized by terms such as Granitic Pegmatites, Geochemistry, Fractionation, S-type Granites, and Rare Elements, reflecting the focus on magmatic evolution and mineral exploration.

What is the significance of the "Albite subtype" classification mentioned?

The study concludes that the Jema'a pegmatites belong to the Albite subtype within the Lithium-Cesium-Tantalum (LCT) family, which is significant for understanding the melt's degree of fractionation.

How do the authors link pegmatites to the surrounding host rocks?

The authors demonstrate that the metasomatized host rocks (amphibolite/migmatite) indicate the migration of pegmatite-derived fluids, serving as a vital exploration tool for discovering mineralized zones.