The Earth Crust | Jamb(UTME) Geography

The Earth Crust

1. Earth's Crust - The outermost layer of the Earth, consisting of solid rock.
2. Thickness of the Crust - The crust varies in thickness, ranging from 5 to 70 kilometers.
3. Continental Crust - The crust beneath the continents, thicker (about 30–50 km) and less dense.
4. Oceanic Crust - The crust beneath the oceans, thinner (5–10 km) and denser than continental crust.
5. Composition of the Crust - The crust is primarily composed of silicate minerals like granite and basalt.
6. Moho Discontinuity - The boundary between the Earth's crust and the mantle.
7. Tectonic Plates - Large slabs of the Earth's lithosphere, which include both the crust and the uppermost part of the mantle.
8. Earthquakes - Movements along faults in the crust that release energy.
9. Subduction Zones - Areas where one tectonic plate moves beneath another, often causing earthquakes and volcanic activity.
10. Crust Formation - The crust forms from the cooling of the Earth's molten surface.
    paragraph

The Structure of the Earth (Internal and External)

11. Inner Core - The solid, innermost part of the Earth, made mostly of iron and nickel.
12. Outer Core - A molten layer surrounding the inner core, responsible for Earth's magnetic field.
13. Mantle - A thick layer of semi-solid rock between the crust and the core, involved in convection currents.
14. Lithosphere - The rigid outer layer of the Earth, consisting of the crust and upper mantle.
15. Asthenosphere - The semi-fluid layer of the mantle beneath the lithosphere, where convection currents occur.
16. Lower Mantle - The deeper part of the mantle, denser and more solid.
17. Crust-Mantle Boundary - The boundary between the Earth's crust and the upper mantle, marked by the Moho.
18. Outer and Inner Core Boundary - The boundary between the molten outer core and the solid inner core.
19. Earth's Layers - Earth’s structure includes the crust, mantle, outer core, and inner core.
20. Plate Tectonics - The theory that Earth's lithosphere is divided into plates that move and interact.
    paragraph

Relationships Among the Four Spheres

21. Atmosphere - The layer of gases surrounding the Earth, crucial for weather and climate.
22. Biosphere - The part of Earth that contains life, including all ecosystems and living organisms.
23. Hydrosphere - All the water on Earth, including oceans, rivers, lakes, and groundwater.
24. Geosphere - The solid Earth, including the crust, mantle, and core.
25. Interdependence - The four spheres interact with each other in various ways, such as water cycle and climate change.
26. Energy Flow - Energy from the Sun drives processes in the atmosphere, biosphere, and hydrosphere.
27. Carbon Cycle - The movement of carbon between the atmosphere, biosphere, hydrosphere, and geosphere.
28. Water Cycle - The continuous movement of water through evaporation, condensation, precipitation, and infiltration.
29. Earth’s Heat - Geothermal energy from the Earth's interior affects both the geosphere and atmosphere.
30. Life and the Spheres - Life in the biosphere is directly impacted by conditions in the atmosphere, hydrosphere, and geosphere.
    paragraph

Types of Rocks

31. Igneous Rocks - Rocks formed from the cooling and solidification of molten magma or lava.
32. Sedimentary Rocks - Rocks formed from the accumulation and compaction of sediments.
33. Metamorphic Rocks - Rocks that have been altered by heat, pressure, or chemical processes.
34. Intrusive Igneous Rocks - Igneous rocks that form inside the Earth, such as granite.
35. Extrusive Igneous Rocks - Igneous rocks that form on the Earth's surface, such as basalt.
36. Clastic Sedimentary Rocks - Formed from the compression of fragments of other rocks, like sandstone.
37. Chemical Sedimentary Rocks - Formed from the evaporation of water, leaving minerals behind, like limestone.
38. Organic Sedimentary Rocks - Formed from the remains of plants and animals, like coal.
39. Foliated Metamorphic Rocks - Rocks that exhibit a layered structure due to pressure, like slate.
40. Non-foliated Metamorphic Rocks - Metamorphic rocks without a layered structure, like marble.
    paragraph

Characteristics of Rocks

41. Hardness - A measure of a rock's resistance to scratching, influenced by mineral composition.
42. Porosity - The amount of empty space within a rock that can store fluids like water or oil.
43. Density - The mass of a rock per unit volume, influenced by mineral content.
44. Color - The color of a rock is influenced by its mineral composition and weathering.
45. Texture - The size, shape, and arrangement of the minerals in a rock.
46. Strata - Layers of sedimentary rock formed over time.
47. Grain Size - The size of the individual mineral particles in a rock.
48. Cementation - The process by which minerals crystallize and bind particles together in sedimentary rocks.
49. Metamorphic Foliation - The alignment of mineral grains in a metamorphic rock due to pressure.
50. Crystal Formation - The process by which minerals in igneous rocks form crystals as the magma cools.
    paragraph

Modes of Formation of Rocks

51. Cooling of Magma - Igneous rocks form from the cooling of molten magma or lava.
52. Compaction and Cementation - Sedimentary rocks form from the compression of sediments over time.
53. Heat and Pressure - Metamorphic rocks form from the alteration of pre-existing rocks under heat and pressure.
54. Lava Flow - The solidification of lava on the Earth’s surface forms volcanic rocks.
55. Sediment Deposition - Sedimentary rocks form as sediments are deposited in layers and compacted.
56. Contact Metamorphism - Metamorphic rocks form when rocks are heated by contact with molten lava or magma.
57. Regional Metamorphism - Metamorphism that occurs over large areas due to tectonic forces, forming foliated rocks.
58. Evaporation - Chemical sedimentary rocks form when water evaporates, leaving minerals behind.
59. Biological Activity - Organic sedimentary rocks form from the accumulation of plant and animal materials.
60. Exhumation - The process by which rocks formed deep in the Earth are brought to the surface through tectonic forces.
    paragraph

Uses of Rocks

61. Building Materials - Rocks like granite and limestone are used in construction.
62. Energy Sources - Coal, oil, and natural gas are derived from sedimentary rocks.
63. Raw Materials - Rocks provide materials for industrial processes, such as iron ore for steel.
64. Landscaping - Rocks like granite and sandstone are used in landscaping and decorative features.
65. Cultural Significance - Certain rocks, such as marble, have cultural and historical significance.
66. Gemstones - Precious stones like diamonds, rubies, and emeralds come from specific rock types.
67. Soil Formation - Weathered rock contributes to the formation of fertile soils.
68. Agricultural Use - Certain rocks are ground into powders and used as fertilizers.
69. Art and Sculpting - Marble and other rocks are carved into statues and sculptures.
70. Road Construction - Crushed rock is used in the construction of roads and highways.
    paragraph

Earth’s Movement

71. Earth's Rotation - The Earth rotates on its axis every 24 hours, causing day and night.
72. Earth's Revolution - The Earth orbits the Sun once every 365.25 days, causing the seasons.
73. Axial Tilt - The tilt of Earth's axis causes seasonal variations in the amount of sunlight different regions receive.
74. Precession - The slow wobble of Earth’s axis, affecting the positions of the stars over long periods.
75. Nutations - Smaller periodic oscillations in Earth's axis superimposed on precession.
76. Earth's Orbital Eccentricity - Earth's orbit is slightly elliptical, affecting the Sun's distance during different times of the year.
77. Orbital Inclination - The slight tilt of Earth’s orbit relative to the plane of the solar system.
78. Earth’s Speed - The Earth moves around the Sun at an average speed of about 30 kilometers per second.
79. Tidal Forces - The gravitational pull of the Moon and Sun causes the tides on Earth.
80. Solar Day vs. Sidereal Day - A solar day is 24 hours, while a sidereal day is approximately 23 hours and 56 minutes.
    paragraph

Tectonic Forces

81. Plate Tectonics - The theory that the Earth's lithosphere is divided into large plates that move and interact.
82. Convergent Boundaries - Areas where tectonic plates move toward each other, often causing mountains or subduction zones.
83. Divergent Boundaries - Areas where tectonic plates move away from each other, leading to the formation of new crust.
84. Transform Boundaries - Areas where tectonic plates slide past each other horizontally, causing earthquakes.
85. Subduction Zones - Where one plate is forced beneath another, often resulting in volcanic activity.
86. Rifting - The process by which tectonic plates move apart, forming rift valleys and oceans.
87. Earthquakes - Sudden movements of the Earth's crust caused by tectonic forces.
88. Volcanic Activity - Volcanic eruptions occur at convergent or divergent plate boundaries due to magma rising from the mantle.
89. Hotspots - Locations where plumes of hot mantle material rise, causing volcanic activity, such as the Hawaiian Islands.
90. Mountain Building - Converging tectonic plates can cause the Earth's crust to fold and form mountain ranges.
    paragraph

Major Landforms

91. Mountains - Elevated landforms created by tectonic forces, such as folding and faulting.
92. Plateaus - Flat, elevated areas often formed by volcanic activity or erosion.
93. Plains - Large, flat areas often created by sediment deposition from rivers or glaciers.
94. Coastal Landforms - Landforms along coastlines, such as beaches, cliffs, and deltas.
95. Karst Topography - Landscapes formed by the dissolution of soluble rocks, leading to features like caves and sinkholes.
96. Desert Landforms - Features such as dunes, mesas, and wadis formed in arid regions.
97. Volcanic Landforms - Landforms like craters, calderas, and lava plateaus formed by volcanic activity.
98. Glacial Landforms - Features such as valleys, moraines, and fjords formed by glacial movement.
99. River Landforms - Features like meanders, deltas, and oxbow lakes formed by river processes.
100. Delta - A landform created by the deposition of sediment at the mouth of a river.
     paragraph

Mountains

101. Fold Mountains - Mountains formed by the folding of the Earth's crust due to tectonic forces, such as the Himalayas.
102. Fault-Block Mountains - Mountains formed by faulting, where blocks of the Earth's crust are uplifted or tilted.
103. Volcanic Mountains - Mountains formed by volcanic activity, such as Mount Fuji in Japan.
104. Mountain Erosion - Over time, mountains are shaped by erosion through wind, water, and ice.
105. Mountain Chains - Long ranges of mountains formed by tectonic plate movements, such as the Andes or the Alps.
     paragraph

Plateau

106. Volcanic Plateaus - Plateaus formed by volcanic activity, such as the Deccan Plateau in India.
107. Erosion Plateaus - Plateaus formed by the erosion of surrounding land, leaving elevated flat areas.
108. Mountain Plateaus - Plateaus found in mountainous regions, such as the Tibetan Plateau.
109. Flat-Top Plateaus - Plateaus with flat surfaces and steep sides, typically formed by erosion or volcanic activity.
     paragraph

Plains

110. Alluvial Plains - Plains formed by the deposition of sediments by rivers, such as the Nile Delta.
111. Coastal Plains - Flat, low-lying plains along coastlines formed by sediment deposition.
112. Flood Plains - Plains formed by river flooding, where sediment is deposited over time.
113. Steppe Plains - Semi-arid plains with grasses and low shrubs, typically found in regions like Central Asia.
     paragraph

Coastal Landforms

114. Cliffs - Steep faces of rock formed along coastlines due to erosion.
115. Beaches - Sandy or pebbly shorelines formed by wave action and sediment deposition.
116. Deltas - Landforms at river mouths formed by sediment deposition, creating a triangular shape.
117. Headlands and Bays - Coastal features where hard rock forms a headland, and softer rock erodes to form a bay.
118. Estuaries - Coastal regions where freshwater from rivers meets saltwater from the ocean.
     paragraph

Karst Topography

119. Caves - Underground spaces formed by the dissolution of soluble rocks like limestone.
120. Sinkholes - Depressions or holes in the ground caused by the collapse of a cave or the dissolution of rock beneath the surface.

I recommend you check my article on the following: