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This is the complete lecture note for MNE104 Physical Geology and Earth History. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • Course code: MNE104 • Course title: Physical Geology and Earth History • Course credit load: 2 Series 1: Planet Earth and Its Composition Series outline • 1.1 Internal Structure of the Earth o 1.1.1 Core o 1.1.2 Mantle o 1.1.3 Crust • 1.2 Composition and Materials of the Earth o 1.2.1 Major Elements and Minerals o 1.2.2 Rock Types and Distribution • 1.3 Dynamic Processes within the Earth o 1.3.1 Heat Flow and Convection o 1.3.2 Plate Tectonics and Movement • 1.4 Planetary Context and Evolution o 1.4.1 Earth in the Solar System o 1.4.2 Geological Time and Earth History Introduction Planet Earth is our home, yet it remains a dynamic and complex system that continues to evolve. From its deep interior to the surface we live on, the Earth is made up of layers and materials that interact to shape the landscapes, resources, and processes we study in geology. Understanding the composition of the Earth is fundamental, because it provides the basis for explaining how landforms develop, how minerals are deposited, and how energy resources are distributed. This Series will therefore set the stage for your journey into physical geology and earth history.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS The aim of this Series is to introduce you to the structure, composition, and dynamic processes of the Earth, and to help you appreciate how these elements connect to the broader geological history of our planet. We shall commence this Series by examining the internal structure of the Earth, focusing on the core, mantle, and crust. Next, we will explore the composition and materials of the Earth, including major elements, minerals, and rock types. Following that, we will consider the dynamic processes within the Earth, such as heat flow, convection, and plate tectonics. Finally, we will wrap up by situating the Earth in its planetary context and evolution, looking at its place in the solar system and its geological time scale. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define the major layers of the Earth and describe their characteristics, • SLO 1.2 explain the composition of the Earth in terms of elements, minerals, and rock types, • SLO 1.3 analyse the dynamic processes within the Earth, including heat flow, convection, and plate tectonics, and • SLO 1.4 evaluate the Earth’s planetary context and geological evolution over time. 1.1 Internal Structure Of The Earth 1.1.1 Core The core is the innermost layer of the Earth, composed mainly of iron and nickel. It is divided into two parts: the solid inner core and the liquid outer core. The inner core is extremely hot, yet remains solid due to immense pressure, while the outer core is molten and responsible for generating the Earth’s magnetic field through the movement of liquid metals. Fill in the blank: The Earth’s ______ core is liquid and generates the magnetic field.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Cross-sectional diagram showing Earth’s internal layers with emphasis on the core. Figure 1.1: Structure of the Earth’s core 1.1.2 Mantle The mantle lies above the core and extends to the crust. It is composed of silicate minerals rich in magnesium and iron. The mantle is semi-solid, and convection currents within it drive plate tectonics. These currents are caused by heat transfer from the core, leading to the slow movement of tectonic plates on the Earth’s surface. Fill in the blank: Convection currents in the ______ are responsible for plate tectonics.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Diagram showing mantle convection currents and their role in plate movement. Figure 1.2: Convection currents in the mantle 1.1.3 Crust The crust is the outermost layer of the Earth, where we live and interact with geological processes. It is relatively thin compared to the mantle and core, and is divided into two types: continental crust, which is thicker and composed mainly of granite, and oceanic crust, which is thinner and composed mainly of basalt. The crust is broken into plates that float on the mantle, and their movement leads to earthquakes, volcanic activity, and the formation of mountains. Fill in the blank: The ______ crust is thicker and mainly composed of granite.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Photograph of a mountain range representing continental crust. Plate 1.1: Continental crust represented by mountain ranges Pilot questions 1.1 1. Which metals primarily make up the Earth’s core? 2. What is the difference between the inner core and the outer core? 3. Which process in the mantle drives plate tectonics? 4. What are the two types of crust, and how do they differ? 5. Which type of crust is thinner and composed mainly of basalt? 1.2 Composition And Materials Of The Earth 1.2.1 Major elements and minerals The Earth is composed of a variety of elements, which are basic chemical substances that cannot be broken down further. The most abundant elements in the Earth’s crust are oxygen, silicon, aluminium, iron, calcium, sodium, potassium, and magnesium. These elements combine to form minerals, which are naturally occurring inorganic substances with a definite chemical composition and crystalline structure. Minerals are the building blocks of rocks and are essential for understanding geological processes. Fill in the blank: The most abundant element in the Earth’s crust is ______.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Table 1.1: Major elements in the Earth’s crust and their approximate percentages 1.2.2 Rock types and distribution Rocks are solid aggregates of one or more minerals. They are classified into three main types based on their origin: • Igneous rocks, formed from the cooling and solidification of molten magma or lava. • Sedimentary rocks, formed from the accumulation and compaction of sediments. • Metamorphic rocks, formed when existing rocks are altered by heat, pressure, or chemical processes. The distribution of these rock types varies across the Earth. For example, igneous rocks are common in volcanic regions, sedimentary rocks dominate basins and plains, while metamorphic rocks are often found in mountain belts. Fill in the blank: Rocks formed from the cooling of magma are called ______ rocks.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Diagram showing the rock cycle and the interrelationship between igneous, sedimentary, and metamorphic rocks. Figure 1.3: The rock cycle Pilot questions 1.2 1. List three of the most abundant elements in the Earth’s crust. 2. Define a mineral and explain its importance in geology. 3. What are the three main types of rocks, and how are they formed? 4. Which type of rock is most commonly found in volcanic regions? 5. What process leads to the formation of metamorphic rocks? 1.3 Dynamic Processes Within The Earth 1.3.1 Heat flow and convection Heat flow refers to the movement of thermal energy from the Earth’s interior towards the surface. This energy originates mainly from the decay of radioactive elements and residual heat from the planet’s formation. The transfer of heat drives important geological processes, including the movement of molten material in the mantle. Convection is the circulation of material caused by differences in temperature and density. In the mantle, hotter and less dense material rises, while cooler and denser material sinks. This slow but continuous movement is a key mechanism behind plate tectonics, influencing the creation of new crust at mid-ocean ridges and the destruction of old crust at subduction zones.
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