GEO101 Introduction to Mineralogy and Petrology

Miss N. S. Mpofu
Zimbabwe School of Mines
Department of Mining Geology

Course Outline

Objectives

  • By the end of the course, the trainee should be able to:
    • Define the terms:
    • Mineral: A naturally occurring inorganic solid with a definite chemical composition and crystalline structure.
    • Crystallography: The study of crystal structures and their properties.
    • Describe physical properties of minerals:
    • Use these properties to identify minerals through hand specimen techniques.
    • Describe the symmetry of the six major crystal classes.
    • Classify and identify rocks based on their characteristics.
    • Discuss the rock cycle and volcanism: Understanding the processes involved in the formation of rocks through geological processes.
    • Describe the formation of different rock classes:
    • Igneous, metamorphic, sedimentary.
    • Adhere to international standards when naming rocks.

MINERALOGY

Introduction

  • Scope of mineralogy: Detailed study of minerals including their formation, classification, and properties.

Physical Properties of Minerals

  • Utilization in identification: Techniques for using mineral properties to accurately identify them.

Classification of Minerals

  • Mineral classes:
    • Native Elements: Pure elements that occur in nature (e.g. gold, silver).
    • Oxides and Hydroxides: Compounds consisting of oxygen and hydroxyl groups (e.g. hematite - Fe2O3Fe_2O_3).
    • Sulphides and Sulphosalts: Minerals containing sulfide ions (e.g. pyrite - FeS2FeS_2).
    • Silicates: The largest group of minerals, composed of silicon-oxygen tetrahedra.
    • Carbonates, Nitrates, and Borates: Comprising carbonate groups (e.g. calcite - CaCO3CaCO_3).
    • Chromates, Halides, Tungstates: Varied groups based on their unique chemical compositions.
    • Molybdates, Phosphates, and Arsenates: Minerals that contain molybdate, phosphate, or arsenate groups respectively.

CRYSTALLOGRAPHY

Key Concepts

  • Crystallographic Terms: Vocabulary and definitions used in the field of crystallography.

Formation of Crystals

  • Crystals from solutions: Processes involved in crystal formation, including nucleation and growth.

Crystal Morphology

  • Measurement of crystal angles: Techniques used to measure and describe the angles formed between crystal faces.

Crystal Classes

  • Identify, describe, and compare crystal classes: Understanding the distinct types of crystal systems, based on symmetry and other properties.

Twinning and Twin Crystals

  • Description and identification: Defining twinning phenomena in crystals and identifying minerals exhibiting these characteristics.

Crystal Chemistry

  • Structure and chemical composition of minerals: Overview of the elemental makeup of the Earth's crust.
    • Bonding Forces and Coordination Principle: Discuss various forces that hold crystals together and how atoms are arranged around a central atom.
    • Factors affecting crystal structure: Conditions that influence how minerals crystallize, including temperature and pressure.

PETROLOGY

Introduction to Petrology

  • Overview of the study of rocks and how geological processes affect their formation.

Igneous Petrology

Volcanism
  • Present-day igneous activity and relation to plate tectonics: Understanding current volcanic activity through the lens of plate boundaries.
  • Factors affecting eruption and types of lava flows:
    • Characteristics of lava flow types based on magma composition and eruption dynamics.
  • Submarine Volcanism: Processes and products related to underwater volcanic activity.
Magmatic Intrusions
  • Mode of Intrusion: How magma enters pre-existing rock layers.
  • Types of Magmas and Structures: Various types of magma (e.g., basaltic, andesitic) and common resulting geological structures.
Melting and Crystallization
  • Magma Generation and Fractional Crystallization: The process by which magma forms and evolves.
  • Evolution of Magmas and Bowen’s Reaction Series: The progression of magma crystallization and the order in which minerals crystallize.

Classification of Igneous Rocks

  • Identification Techniques: Methods for categorizing igneous rocks based on texture and composition.

Metamorphic Petrology

Scope of Metamorphism

  • Agents of Metamorphism: Factors that facilitate the metamorphic process, including heat, pressure, and fluids.
  • Principles of Metamorphism: Fundamental concepts guiding the metamorphic transformation of rocks.

Classification of Metamorphic Rocks

  • Foliated and Non-foliated Rocks: Distinction between rocks exhibiting foliation and those that do not.
  • Nomenclature: The naming conventions used for various types of metamorphic rocks.

Identification of Metamorphic Rocks

  • Mineralogy and Texture: Description of key mineral components and textural characteristics of common metamorphic rocks.
  • Economic Importance: Discussion of the economic significance of various metamorphic rocks.
  • Metamorphic Facies and Grade: Definitions and explanations of metamorphic facies and their grades.
  • Zones of Progressive Regional Metamorphism and Contact Metamorphism: Outline of the different metamorphic environments and their characteristics.
  • Metamorphic Fabrics: Examination of structures formed in metamorphic rocks.
  • Relate Metamorphism, Magmatism, and Orogeny: Discuss interconnections between these geological processes.

Sedimentary Petrology

Formation of Sedimentary Rocks

  • Statistical Parameters in Sediments: Statistical analyses that characterize sediment compositions.
  • Characteristics of Sedimentary Rocks: Key properties that define and distinguish sedimentary rocks.
  • Depositional Environments for Sediments: Environmental settings conducive to sedimentation processes.

Sedimentary Structures

  • Primary and Secondary Structures: Terms used to describe features formed during sediment disposal and alterations thereafter.
    • Primary Structures: Formed during deposition and include erosional, deposition, post-depositional, and biogenic structures.
    • Secondary Structures: Resulting from geological processes after initial sediment deposition.
  • Discussion on Stratigraphy of Sediments: Examination of layering and historical geology.

Classification of Sedimentary Rocks

  • Major Classes and Subdivisions: Identification of principal classes of sedimentary rocks and their subdivisions, with examples.
  • Typical Rocks in Each Class: Listing of common rocks found within each sedimentary subclass.

Identification of Sedimentary Rocks

  • Mineralogy and Texture: Techniques for determining composition and textural features of sedimentary rocks.
  • Economic Importance: Overview of the economic value of sedimentary rock classes.

References

  • Martin Okrusch and Hartwig E. Frimmel, Mineralogy: An Introduction to Minerals, Rocks and Mineral Deposits. Springer Nature, 2020.
  • Melinda Darby Dyar and Mickey E Gunter, Mineralogy and Optical Mineralogy, Second Edition. Mineralogical Society of America, 2008.
  • B. Ronald Frost and Carol D. Frost, Essentials of Igneous and Metamorphic Petrology, Second Edition. Cambridge University Press, 2019.
  • John D. Winter, Principles of Igneous and Metamorphic Petrology, 2013.
  • Dexter Perkins, Petrology: An Introduction to Igneous and Metamorphic Petrology. University of North Dakota, 2022.

Regulations

  • All practical assignments are compulsory.
  • Students cannot write an exam if they have less than 40% of points in coursework (including practical, tests, and assignments).
  • Coursework constitutes 60% of the final grade:
    • 3 practical assignments
    • 1 assignment
    • Test

Office Hours

  • Available any time if the instructor is available.