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Questions and Answers
Which mineral is primarily found in the Western and Southwestern greenstone belt?
Which mineral is primarily found in the Western and Southwestern greenstone belt?
The Southern greenstone belt is also known as the Adola belt.
The Southern greenstone belt is also known as the Adola belt.
True
Name one site where gold occurrences are found in the Northern greenstone belt.
Name one site where gold occurrences are found in the Northern greenstone belt.
Terakemti
The Southern greenstone belt includes primary gold deposits at ________ and Sakaro.
The Southern greenstone belt includes primary gold deposits at ________ and Sakaro.
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Match the following mineral occurrences with their respective belts:
Match the following mineral occurrences with their respective belts:
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What is the primary focus of geology?
What is the primary focus of geology?
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The Big Bang theory suggests that the universe was once concentrated into a single point.
The Big Bang theory suggests that the universe was once concentrated into a single point.
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Who proposed the theory of continental drift?
Who proposed the theory of continental drift?
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According to the Big Bang theory, the universe is made up of approximately _____% Hydrogen.
According to the Big Bang theory, the universe is made up of approximately _____% Hydrogen.
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Match the following geological methods with their descriptions:
Match the following geological methods with their descriptions:
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Which of the following statements about the early universe is true?
Which of the following statements about the early universe is true?
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Little attention was given to Alfred Wegener's theory of continental drift at its inception.
Little attention was given to Alfred Wegener's theory of continental drift at its inception.
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The explosion that led to the formation of the universe is known as the _____ theory.
The explosion that led to the formation of the universe is known as the _____ theory.
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What was the name of the supercontinent that existed over 200 million years ago?
What was the name of the supercontinent that existed over 200 million years ago?
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Gondwanaland included present-day North America.
Gondwanaland included present-day North America.
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Name two geological processes classified as internal processes.
Name two geological processes classified as internal processes.
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Pangaea began to break apart into two supercontinents: ________ and ________.
Pangaea began to break apart into two supercontinents: ________ and ________.
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Which of the following supports the idea of continental drift based on fossil distribution?
Which of the following supports the idea of continental drift based on fossil distribution?
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Match the following groups of geological processes with their classifications:
Match the following groups of geological processes with their classifications:
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Paleoclimatic evidence shows that rocks from different continents exhibit signs of ancient glaciations.
Paleoclimatic evidence shows that rocks from different continents exhibit signs of ancient glaciations.
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What observation did early map makers make regarding the continents?
What observation did early map makers make regarding the continents?
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What is NOT a structural effect of the Rift Valley formation?
What is NOT a structural effect of the Rift Valley formation?
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The Aden volcanic activities are primarily located in the northern region of the Rift Valley.
The Aden volcanic activities are primarily located in the northern region of the Rift Valley.
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During which geological period did the major climatic changes occur, including the last Ice Age?
During which geological period did the major climatic changes occur, including the last Ice Age?
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The _____ series includes numerous freshly preserved volcanic cones and extensive lava fields.
The _____ series includes numerous freshly preserved volcanic cones and extensive lava fields.
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Match the following lakes with their respective combined lake groups:
Match the following lakes with their respective combined lake groups:
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Which phenomenon caused the excessive surface flow and the merging of lakes during the Quaternary period?
Which phenomenon caused the excessive surface flow and the merging of lakes during the Quaternary period?
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The rate of evaporation increased after the Pluvial Rains, resulting in smaller lake sizes.
The rate of evaporation increased after the Pluvial Rains, resulting in smaller lake sizes.
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Name one characteristic feature of the volcanic landscape in the Aden region.
Name one characteristic feature of the volcanic landscape in the Aden region.
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What major geological process occurred during the Cenozoic Era?
What major geological process occurred during the Cenozoic Era?
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The Upper Sandstone is the oldest sedimentary rock in the geological timeline.
The Upper Sandstone is the oldest sedimentary rock in the geological timeline.
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What is the primary geological activity associated with the uplifting of the Arabo-Ethiopian landmass?
What is the primary geological activity associated with the uplifting of the Arabo-Ethiopian landmass?
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The sedimentary rock known as _____ limestone was formed during the Jurassic Period.
The sedimentary rock known as _____ limestone was formed during the Jurassic Period.
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Match the geological periods with their associated activities:
Match the geological periods with their associated activities:
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Which layer of marine sediment is considered to have formed first?
Which layer of marine sediment is considered to have formed first?
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Dinosaurs emerged during the Cenozoic Era.
Dinosaurs emerged during the Cenozoic Era.
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What significant uplift occurred during the Eocene epoch associated with the Arabo-Ethiopian landmass?
What significant uplift occurred during the Eocene epoch associated with the Arabo-Ethiopian landmass?
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Which of the following is NOT a subdivision of the Geological Time Scale?
Which of the following is NOT a subdivision of the Geological Time Scale?
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The Carbon-14 Technique is used for relative dating of rocks.
The Carbon-14 Technique is used for relative dating of rocks.
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What is the approximate half-life of Carbon-14?
What is the approximate half-life of Carbon-14?
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The _____ Era is known as the age of reptiles.
The _____ Era is known as the age of reptiles.
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Which technique can be used to date entire rock samples?
Which technique can be used to date entire rock samples?
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Name one way to determine the relative age of rocks.
Name one way to determine the relative age of rocks.
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Match the following Geological Eras with their characteristics:
Match the following Geological Eras with their characteristics:
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Environmental conditions have no impact on the Geological Time Scale.
Environmental conditions have no impact on the Geological Time Scale.
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Study Notes
Course Information
- Course Title: Geography of Ethiopia and the Horn
- Course Code: GeES 1011
- Credit hours: 3
- Instructor's Name: Ashenafi Z. (PhD Candidate)
- Date: Nov, 2024
Chapter Two: The Geology of Ethiopia and the Horn
2.1 The Geology of Ethiopia and the Horn
- Geology is the Earth science that studies the evolution of the planet, its materials, and the processes that affect it.
- Much of geology focuses on events from the distant past, and features located deep within the Earth, which are not directly observable.
- Understanding relies heavily on indirect evidence and inferences based on what can be seen and measured on the surface.
- Clues include various rock and landform observations, and indirect methods like geophysics (studying earthquake waves), geochemistry (analyzing rock composition), and geochronology (determining rock ages).
2.2 Origin of the Universe: The Big Bang Theory
- The universe is all of space and everything within it.
- The Big Bang theory explains the universe's origin as the result of a massive explosion from a high-density, high-temperature point.
- All the matter in the known universe was once concentrated in a single point, known as a cosmic egg.
- After the explosion, the universe expanded, and cooled down to form an expanding cloud of gases, primarily hydrogen (73%) and helium (27%).
- Thermonuclear fusion occurred, giving rise to stars. The Sun's first rays arose from a tremendous temperature of 11 million °C about 4.5 billion years ago after the birth of the stars and formation of the first galaxies.
- The Earth formed from the collapsing nebular material and took about 700 million years to cool down and solidify.
2.3 The Theory of Continental Drift
- Alfred Wegener, a German meteorologist, proposed the theory of continental drift.
- Wegener's theory suggests that the Earth's continents were once joined together as a single large landmass called Pangaea.
- Pangaea was surrounded by a vast ocean known as Panthalassa.
- Pangaea broke apart into Gondwanaland and Laurasia during the Mesozoic era, roughly 200 million years ago.
- Gondwanaland further separated into South America, Africa, the Arabian Peninsula, India, Australia, and Antarctica.
- Laurasia separated into North America and Eurasia.
- Supporting evidence for the theory includes the fit of continents, similarities in mountain belts and rock types, distribution of fossils, and similar ancient climates.
2.4 The Geological Processes
- Geological processes are broadly categorized into internal (endogenic) and external (exogenic) processes.
- Internal processes (endogenic): include earthquakes, volcanism, mountain building, and landmass sinking.
- External processes (exogenic): include weathering, mass transfer, erosion, and deposition.
- The landforms of Ethiopia are formed by the combined effect of both types of processes.
2.5 The Geological Time Scale
- The Geological Time Scale is a record of Earth's history, organized into four major divisions: Eon, Eras, Periods, and Epochs.
- This scale is structured based on significant geological events, major shifts in life forms, and environmental changes.
- The categories do not have uniform lengths of time.
2.5.1 Age Dating Techniques
- Scientists use two main techniques of determining rock ages:
- Relative dating: uses geological evidence to show comparative ages of fossils, identifying which layer is older or younger.
- Absolute dating (Radiometric): determines the actual age of rocks, using radioactive decay to calculate the age.
2.5.1.A. Carbon-14 Technique
- Using the known and predictable rate of carbon-14 decay after an organism dies. The half-life is 5730 years.
2.5.1.B. Potassium-40 Technique
- Potassium-40 decays into Argon-40, which is measured to determine the rock's age.
- The method relies on the abundance of potassium-40 in minerals like micas, feldspars and hornblendes.
- Potential problem: Leakage of Argon from a rock due to high temperatures affecting the accuracy of the measurements.
2.6 Geological Processes and the Resulting Landforms of Ethiopia and the Horn
- Covers the geologic events from 4.5 Billion years ago to the present.
2.6.1 The Precambrian Era (4.5 - 600 Million Years Ago)
- Covers the oldest and longest period of Earth's history.
- Major geological events include: crystalline basement rock formation, orogenesis (mountain building), metamorphism (formation of metallic minerals), intensive volcanic activity, and the first forms of life emerged.
- Our understanding of this era is limited due to its remoteness in time and the absence of well-preserved fossils.
2.6.2 The Paleozoic Era (600-225 million years ago)
- The second-longest and second-oldest Era.
- Major geological processes: Denudation, peneplanation (reducing mountains to a flat surface), heavy erosion, and coal formation.
- Limited significant rock formations in Ethiopia during this period due to limited deposition.
2.6.3 The Mesozoic Era (225-70 million years ago)
- The third-largest and third-oldest Era.
- Major geological processes involved in the shaping of landmasses: movement of continents (continental drift), sinking and uplifting of land masses (epeirogenesis), formation of 3 layers of marine sediments, emergence and extinction of dinosaurs, and the emergence of mammals, birds, and flowering plants.
- Landmass has experienced alternating periods of sinking and uplift, and is the period when Pangaea split into Gondwanaland and Laurasia.
2.6.4 The Cenozoic Era (70 million years ago - Present)
- This is the most recent Era.
- Major geological processes: Uplift of the Arabo-Ethiopian landmass, outpouring of huge quantities of lava, formation of the Rift Valley, and quaternary volcanism and deposition.
2.7 Rock and Mineral Resources of Ethiopia
- Rocks are naturally formed aggregates of one or more minerals. These are considered natural, inorganic substances with definite chemical compositions and specific internal structures.
- Metallic mineral occurrence primarily associated with Precambrian rocks.
- Mineral potential in Ethiopia is high but not adequately or fully utilized because of a lack of technology, skill, and capital.
2.7.1 Brief Facts and Current State of Main Minerals in Ethiopia
- Ethiopia has an abundance of resources of metals and precious metals, coal, and industrial minerals like Gold, Platinum, Tantalum, Gemstones, Potash, Gypsum, etc.
- However, there is a gap between the mineral potential and current level of utilization, due to the absence of technology, capital, and skilled personnel.
2.7.2 Mineral Potential Sites of Ethiopia
- Based on Ethiopian geological surveys, the potential mineral occurrence areas include three major greenstone belts and other formations. These areas (Western and South-Western, Southern, and Northern) are known to contain various mineral types including, primary gold, platinum, base metals, etc.,
3. Quaternary Volcanic Eruptions and Depositions
- Recent volcanic activities after the formation of the Rift Valley during Pliocene-Pleistocene Epochs.
- Volcanic activity is generally limited to Rift Valley floor and the region south of Lake Tana, with more extensive activity in the Afar region.
- Well-preserved volcanic morphological features are readily seen in the Afar area owing to their recent occurrence. (volcanic cones, hills, mountains, lava fields, ridges).
Quaternary Deposition
- Earth experienced marked climatic change with alternating warmer and colder periods during the Quaternary. Pluvial periods (periods with heavy rainfall) also occurred in Africa.
- Excessively increased pluvial rainfall caused significant effects on land including increased surface flow, river erosion of the Ethiopian plateau, sediment and water transport by the rivers, and creation of numerous lakes.
- These effects have led to the formation of lacustrine, fluvial, and glacio-fluvial deposits which cover considerable areas in the form of lakebeds, river valleys, etc.
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Description
Test your knowledge on geology topics including greenstone belts, mineral occurrences, and fundamental theories like the Big Bang and continental drift. This quiz will challenge your understanding of both mineralogy and the history of the universe. Get ready to explore the fascinating world of geology!
